The URL can be used to link to this page

WPCP Facility Plan_Strand Associates IDNR SubmissionTHE CITY OF DUBUQUE Masterpiece on the Mississippi Dubuque All-American City 2007 TO: The Honorable Mayor and City Council Members FROM: Michael C. Van Milligen, City Manager SUBJECT: WPCP Facility Planning Recommendation DATE: May 27, 2008 Consistent with the direction from the May 19, 2008 City Council meeting, Water Pollution Control Plant Manager Jonathan Brown is recommending approval of the submittal to the Iowa Department of Natural Resources by Strand Associates the Facility Plan for the Water Pollution Control Plant. I concur with the recommendation and respectfully request Mayor and City Council approval. Michael C. Van Milligen MCVM/jh Attachment cc: Barry Lindahl, City Attorney Cindy Steinhauser, Assistant City Manager Jonathan Brown, Water Pollution Control Plant Manager THE CITY OF DUBUQUE Masterpiece on the Mississippi Dubuque All-American City 2007 TO: Michael C. Van Milligen, City Manager FROM: Jonathan R. Brown, WPCP Manage SUBJECT: WPCP Facility Planning Recommendation DATE: May 27, 2008 INTRODUCTION The purpose of this memo is to present the Facility Plan for the Water Pollution Control Plant for approval and to request that Strand Associates be authorized to submit this plan to the Iowa Department of Natural Resources for review. BACKGROUND The City of Dubuque operates a wastewater treatment plant providing secondary treatment for residential, commercial, and industrial wastewaters. The treatment facilities are complex, energy intensive and involve high replacement costs as units reach the end of their useful lives. The original facilities were designed and built over forty years ago and updated in 1994. The need to replace plant components and the desire to reduce plant operating costs prompted the City to prepare a Facility Plan to identify the best alternatives for sludge handling, biological wastewater treatment, alternative disinfection methods, and to review other plant needs. The direction of the City of Dubuque's WPCP has been established as a high priority by the City Council. A process of facility planning was approved and RFP's for the Water Pollution Control Facility Plan were submitted to council on February 5, 2007. Consultant selection to prepare the Facility Plan was approved by City Council in May 2007 and Strand Associates of Madison WI was contracted to proceed with planning. The objectives of the Facility Plan are as follows: 1. An assessment of the current condition of the WPCP. 2. Alternatives for sludge disposal with related costs and impacts. 3. Secondary treatment plan. 4. Disinfection alternatives with related costs and impacts. 5. Fulfill the requirements of the State of Iowa Revolving fund program for the possibility of funding plant upgrades. 6. A prioritized list of plant upgrades for possible phasing of plant construction. 7. An analysis of the probability of nutrient removal requirements for the WPCP. 8. A Facility Plan that has been developed with input from all interested Dubuque citizens and City staff. DISCUSSION Strand Associates has completed the facility planning process and submitted the planning document for review by City Staff. The recommended plan includes improvements to nearly all portions of the existing WPCP. The following is a brief summary of the recommended improvements: Influent Screening • Replace the existing screens with 1/4-inch fine screens (consider 1/8-inch screens) • Install screenings washer/compactor Grit Removal • Replace the existing grit classifiers • Eliminate the need for dewatered grit conveying by reorienting the grit classifiers • Reconfigure grit pump discharge piping Primary Treatment • Remove domed covers and replace with weir covers only • Construct 4th primary clarifier Biological Treatment • Continue with High Purity Oxygen (HPO) activated sludge, including hauling liquid oxygen to the plant • Replace aeration mixers (27) • Replace HPO controls for all three trains • Inspect concrete deck • Seal concrete deck Final Clarification • Install new energy dissipating inlets Effluent Disinfection • Replace chlorination and dechlorination with ultraviolet light disinfection • Reuse contact tank for UV installation Effluent DO and pH Control • Routinely monitor the wastewater DO and pH downstream of the aeration basins to determine how DP and pH change through the remaining basins Based on this monitoring: • Install a cascade aeration system downstream of the dechlorination basin. This will serve to release CO2 to raise the effluent pH. • If needed, remove the final stage concrete deck from each HPO train, which will serve to release CO2 raise the effluent pH. Peak Flow Management • Convert trickling filter structures to off-line flow equalization downstream of primary clarification. • Modify HPO basins to all operation in contact stabilization mode of activated sludge. Sampling and Flow Metering • Provide two new influent samplers • Provide new effluent sampler and sampling enclosure near the chlorine contact tank Residuals Management • Decommission the fluid bed incinerators. • Construct new anaerobic digestion facilities (TPAD) • Install new WAS thickening equipment in the existing incinerator building. • Rehabilitate the WAS storage tanks and provide new WAS storage aeration equipment. • Provide two new dewatering centrifuges; remove one existing centrifuge (use for parts) • Convert existing incinerator building to biosolids cake storage and load-out facilities. • Consider electrical generation for biogas. • Establish contract with biosolids contractor to provide hauling, off-site storage, and land application of biosolids. Emergency Backup Power and Electrical Service • Install new emergency power generation equipment. • Consider two smaller generators since there are two electrical services at the plant. • Consider consolidating biogas electrical generation and backup power generation equipment. • Replace electrical switchgear and distribution equipment from the 1970's and before. Administration Building, Laboratory, and Locker Rooms • Conduct space needs study • Refurbish the existing administration building • Refurbish locker rooms in the administration building and the incinerator building. • Expand the laboratory portion of the building by approximately 700 ft2 Vehicle Storage and Maintenance Building • Construct new facility for vehicular storage and maintenance (approximately 4, 800-ft2) Sewer Cleaning Debris Pad • Construct new receiving station for sewer cleaning debris to allow dewatering and storage for this material. • Consider incorporating a hauled waste receiving station into this facility. Odor Control • Provide ability to install odor control for the headworks and primary clarifiers in the future. Other Equipment Replacement • Influent magnetic flow meters (2), effluent flow meter, and excess flow meter. • Primary clarifiers drives • Primary scum pumps • Primary sludge transfer pumps • RAS pump VFD replacement • WAS pumps • In-plant waste/recycle pumps • Plant effluent/process water pump • HVAC systems Miscellaneous Piping, Valves, Mechanical and Other Components • Influent channel gates • Primary clarifier splitter gates • MLSS splitter gates • Final clarifier influent splitter gates • Reroute in-plant waste/recycle pump discharge upstream of the influent screens. • New septage/hauled waste receiving station • New roofs on existing buildings The opinion of capital costs for the recommended improvements is approximately $48 million (December 2007 costs basis). Table 7.02-1 of the facility planning document presents a summary of the opinion of capital costs. (Attachment I) This project is recommended to be financed by State Revolving Loan funds, which offer 0% interest on the design loan and abelow-market interest rate of 3.25% for the construction loan. The impact on rates for construction of the Water Pollution Plant Upgrade is as follows (see attached graphs): (Attachments II) FY 2009 FY 2010 FY 2011 FY 2012 FY 2013 FY 2014 0% 8% 7% 12% 13% 11% The impact on rates for construction of the Water Pollution Plant Upgrade and the normal planned increases are as follows (see graphs attached): (Attachment III) FY 2009 FY 2010 FY 2011 FY 2012 FY 2013 FY 2014 0% 13% 14% 17% 18% 16% In Fiscal Year 2009, Dubuque will still maintain the position of second lowest sewer rate as shown in the following table: Sanitary Sewer Comparison Sanitary Sewer Rate Comparison for Average User City FY08 FY09 Iowa City $34.36 $36.08 Sioux City $22.45 $27.04 Des Moines $26.78 $26.78 West Des Moines $22.20 $24.50 Council Bluffs $17.20 $20.64 Davenport $19.19 $20.63 Ames $18.45 $19.99 Waterloo $18.95 $18.95 Cedar Rapids $14.91 $16.80 Average Without Dubuque $21.61 $23.49 The highest ranked city (Iowa City) is 100% higher than Dubuque's rate, and the average is 30.1 % higher than Dubuque. In addition, many of the larger cities in Iowa have planned Water Pollution Plant Upgrades that will require significant future rate increases. These cities include Davenport, Cedar Rapids, Sioux City, Council Bluffs, and Ames. The preliminary project implementation schedule is included below. The schedule assumes an approximate two-month review and approval duration for the IDNR for the facilities plan and future design documents: • Facilities Plan Submittal to IDNR June 2008 • Public Hearing July 2008 • IDNR Approval August 2008 • Begin Design Early Fall 2008 • Submit Design Documents to IDNR Summer 2009 • Construction Bid Date Fall 2009 • Construction Completion December 2012 ACTION REQUESTED I respectfully request that the City Council approve the Facility Planning Document and authorize Strand Associates to submit the plan to the Iowa Department of Natural Resources. Attachment cc: Cindy Steinhauser, Assistant City Manager Jenny Larson, Budget Director City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 7- Recommended Plan and Fiscal Impact Analyses TABLE 7.02-1 OPINION OF CAPITAL COSTS Project Component Opinion of Capital Cost Influent Screenin E ui ment and Channel Modifications $510,000 Grit Removal Grit Classifiers and Conve or Modifications $105,000 Primar Treatment Dome Removal and New Covers $203,000 4th Prima Clarifier a ui ment and structure $1,200,000 HPO Activated Slud e New Mixers, Drives, and Motors $1,438,000 New Controls $547,000 Concrete Deck Restoration $350,000 Final Clarifiers New LA-EDI and Stillin Wells $227,000 Disinfection UV E ui ment and Tank Modifications $901,000 DO and H Limits Cascade Aeration $70,000 Monitorin E ui ment $25,000 Peak Flow Mana ement E ualization Tank and S litter Structure Modifications $500,000 Contact Stabilization Modifications $200,000 Residuals Mana ement Stabilization S stem $8,939,000 Dewaterin , Thickenin ,and Conve in E ui ment and Stora a $2,192,000 WAS Stora a Aeration E ui ment $318,000 Buildin Modifications Allowance $500,000 Sam lin Influent Sam lers $18,000 Effluent Sam lers and FRP Bld $25,000 Emer enc Backu Power Generators $480,000 Miscellaneous E ui ment Re lacement $ 770,000 Subtotal E ui ment and Structures $19 518 000 Undefined Subcontract Work Site Work $976,000 Prepared by Strand Associates, Inc.® Page 1 of 2 TMS:pII\S:\CDSAI\151--200\154\002\Wrci\Report\Table 7.02-t.doc\051508 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 7- Recommended Plan and Fiscal Impact Analyses HVAC $1,366,000 Mechanical $3,904,000 Electrical $3,904,000 Allowances Miscellaneous Demolition $250,000 Miscellaneous Pi in ,Valves, and Mechanical Com onents $500,000 Electrical Service $200,000 MCC Re lacement $500,000 Admin. Bld Refurbishment 80'x35'x2 floors $700,000 Admin Bld .Lab Addition 35X20x2 floors $315,000 Solids Processin Bld Locker Room Refurbishment $100,000 Vehicle Stora a and Maintenance Buildin 3-ba ; 80'x60' $720,000 Sewer Cleanin Debris Pad $50,000 Se to a Receivin Station $75,000 Subtotal $33,078,000 Contractors General Conditions $2,646,000 Subtotal $35,724,000 Technical Services and Contin encies $12,503,000 TOTAL OPINION OF CAPITAL COSTS December 2007 $ $48,227,000 Prepared by Strand Associates, Inc.® Page 2 of 2 TMS:pII\S:\@SAI\151--200\154\002\Wrd\Report\Table 7.02-1.doc\051508 ~, N O A C7 ~r O -~, n N tD N n O N n ~. rn ° o o N ? _o °~ T N O A n rF N n O N C C7 _~ O~ 'O C N Z O n O N ~' ~ Oc -Professional -Engineering -Services SA STRAND ASSOCIATES, INC. ENGINEERS RECEIVED 08 MAY 29 PM 2:35 City Clerk's Office Dubuque, IA Report Dubuque Water Pollution Control Plant (WPCP) Facilities Plan City of Dubuque, IA May 2008 Report City of Dubuque, Iowa Dubuque Water Pollition Control Plant (WPCP) Facilities Plan I hereby certify that this engineering document was prepared by me or under my personal supervision and that I am a duty licensed Professional Engineer under the laws of the State of Iowa FOR STRAND ASSOCIATED, INC. Randall A. Wirtz Date License Number 16137 My license renewal date is December 31, 2009 Pages or sheets covered by this seal: Entire Study Prepared by: STRAND ASSOCIATES, INC. 910 West Wingra Drive Madison, WI 53715 www.strand.com May 2008 TABLE OF CONTENTS Page No. or Following SECTION 1-INTRODUCTION 1.01 Purpose and Scope of Report .................................................................... 1-1 1.02 Location of Study ....................................................................................... 1-1 1.03 Related Studies and Reports ..................................................................... 1-1 1.04 Related Drawings and Specifications ........................................................ 1-2 1.05 Abbreviations ............................................................................................. 1-2 SECTION 2-EXISTING WASTEWATER CONVEYANCE FACILITIES 2.01 Background ................................................................................................ 2-1 2.02 Infiltration/Inflow Evaluation ....................................................................... 2-1 SECTION 3-EXISTING WASTEWATER TREATMENT FACILITIES 3.01 Background ................................................................................................ 3-1 3.02 Description of Existing Facilities ................................................................ 3-1 3.03 Influent Flows and Loadings ................................................................ 3-3 3.04 In-Plant Waste Loadings ..................................................................... 3-8 3.05 WPCP Performance and Permit Compliance ............................................ 3-9 3.06 Residuals Management ............................................................................. 3-14 3.07 Industrial Pretreatment Program ................................................................ 3-15 SECTION 4-FLOW AND WASTELOAD FORECASTS 4.01 Sewer Service Area ................................................................................... 4-1 4.02 Population and Growth Projections ............................................................ 4-1 4.03 Projected Flows ......................................................................................... 4-1 4.04 Projected Loadings .................................................................................... 4-3 SECTION 5-EVALUATION OF EXISTING FACILITIES AND SCREENING OF ALTERNATIVES 5.01 Regulatory and NPDES Permitting Issues ................................................. 5-1 5.02 Unit Process Evaluation ............................................................................. 5-7 SECTION 6-WASTEWATER TREATMENT ALTERNATIVES EVALUATIONS 6.01 Introduction ................................................................................................ 6-1 6.02 Influent Screening Alternatives Analysis .................................................... 6-1 6.03 Biological Treatment Alternatives Analysis ................................................ 6-4 6.04 Effluent Disinfection Alternative Analysis ................................................... 6-9 6.05 Residuals Management Alternative Analysis ............................................. 6-12 6.06 Other Recommended Plan Elements ........................................................ 6-22 TABLE OF CONTENTS Continued SECTION 7-RECOMMENDED PLAN AND FISCAL IMPACT ANALYSES 7.01 Recommended Plan Summary .................................................................. 7.02 Opinion of Capital Costs and Project Financing ........................................ 7.03 Opinion of Operation, Maintenance, and Replacement Costs ................... 7.04 Sewer Use Rate Impact of Recommended Plan ....................................... 7.05 Project Implementation Schedule .............................................................. APPENDICES APPENDIX A-CITY OF DUBUQUE WPCP NPDES PERMIT APPENDIX B-ANTICIPATED WLA/PERMIT LIMITS FOR DUBUQUE WPCP APPENDIX C-PRESENT WORTH ANALYSIS APPENDIX D-DETAILED OPINIONS OF COST FOR BIOLOGICAL TREATMENT ALTERNATIVE APPENDIX E-DETAILED OPINIONS OF COST FOR DISINFECTION ALTERNATIVES APPENDIX F-DETAILED OPINIONS OF COST FOR RESIDUALS MANAGEMENT ALTERNATIVES TABLES 3.02-1 Existing Effluent Limitationsa, City OF Dubuque, Iowa .............................. 3.02-2 Dubuque WPCP Existing Facilities ............................................................ 3.03-1 Average Daily Flows (2002-2007) .............................................................. 3.03-2 BOD5 Loadings (2002-2007) ...................................................................... 3.03-3 TSS Loadings (2002-2007) ........................................................................ 3.05-1 Effluent BOD5 (2002-2007) ........................................................................ 3.05-2 Effluent TSS (2002-2007) .......................................................................... 3.05-3 Effluent Ammonia Nitrogen (2002-2007) ................................................... 3.05-4 Effluent Fecal Coliform (2002-2007) .......................................................... 3.05-5 Effluent Chlorine Residual (2002-2007) ..................................................... 3.05-6 Incinerator Emission Limits ........................................................................ 3.06-1 Dubuque WPCP Annual Sludge Quantities (2002-2007) .......................... 4.03-1 Existing Per Capita Flows and Infiltration/Inflow Calculations ................... 4.03-2 Design Flow Projections ............................................................................ 4.04-1 Per Capita BOD Loading Calculations ....................................................... 4.04-2 Per Capita TSS Loading Calculations ........................................................ 4.04-3 Design BOD5 Loading Projections ............................................................ 4.04-4 Design TSS Loading Projections ............................................................... 5.01-1 EPA Recommended Nutrient Criteria for Rivers in Ecoregion VII ............. 5.01-2 Anticipated NPDES Permit Limits .............................................................. Page No. or following 7-1 7-4 7-4 7-5 7-5 3-2 3-2 3-3 3-5 3-5 3-9 3-10 3-10 3-13 3-13 3-14 3-14 4-2 4-3 4-4 4-4 4-6 4-6 5-1 5-5 6.02-1 Influent Screening Opinion of Capital Cost Summary ................................ 6-3 6.03-1 Biological Treatment Opinion of Present Worth Summary ........................ 6-7 6.04-1 Disinfection Opinion Of Present Worth Summary ...................................... 6-10 TABLE OF CONTENTS Continued Page No. or following TABLES (Continued) 6.05-1 Residuals Management Opinion Of Present Worth Summary ................... 6-19 6.05-2 Nonmonetary Evaluations of Residuals Management Alternatives ........... 6-20 6.05-3 Residuals Management Alternatives -Carbon Footprint Analysis ............ 6-21 7.01-1 Unit Process Treatment -Preliminary Design Criteria .............................. 7-1 7.02-1 Opinion of Capital Costs ............................................................................ 7-4 7.03-1 Opinion of Annual O&M Costs -Post Construction ................................... 7-4 FIGURES 1.02-1 Sewer Service Area ................................................................................... 1-1 1.02-2 Planning Area ............................................................................................ 1-1 3.01-1 Existing Site Plan ....................................................................................... 3-1 3.02-1 Existing Process Schematic ....................................................................... 3-2 3.03-1 Total Daily Flow from January 2002 through September 2007 .................. 3-4 3.03-2 Summary of Influent BOD5 Daily Loadings ................................................ 3-6 3.03-3 Summary of Influent TSS Daily Loadings .................................................. 3-6 3.05-1 Summary of Daily BODS Effluent Values ................................................... 3-11 3.05-2 Summary of Daily TSS Effluent Values ..................................................... 3-11 3.05-3 Summary of Daily NH3-N Effluent Values .................................................. 3-12 3.05-4 Summary of Daily pH Effluent Values ........................................................ 3-12 4.02-1 Dubuque WPCP Population Projections .................................................... 4-1 5.01-1 Impaired Waters in Northeast Iowa ............................................................ 5-3 5.02-1 Effect of Sludge Blend on Cake Dryness ................................................... 5-11 5.02-2 Potential Equalization of July 3 and 4, 2007, Rain Event .......................... 5-14 5.02-3 Potential Equalization of July 17 and 18, 2007, Rain Event ...................... 5-14 5.02-4 Contact Stabilization Conversion for Peak Flows ...................................... 5-15 5.02-5 HPO Basin DO Levels (2002 through 2007) .............................................. 5-16 5.02-6 Effluent pH Levels (2002 through 2007) .................................................... 5-18 7.01-1 Recommended Improvements -Site Plan ................................................ 7-1 SECTION 1 INTRODUCTION City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 1-Introduction 1.01 PURPOSE AND SCOPE OF REPORT The City of Dubuque operates wastewater collection and treatment facilities that provide service to City residences, businesses, industries, and public institutions within the City of Dubuque. This Facilities Plan was prepared for the purpose of developing an overall plan for wastewater management at the Dubuque Water Pollution Control Plant (WPCP) for the next 20 years and beyond. This plan must be implemented to meet the requirements of federal and state regulations related to water quality in the Mississippi River. The majority of the current facilities at the Dubuque WPCP were placed in operation in 1975. The last major renovation of the facility was completed in 1996. Based on the age of the facilities and changes in the contributory flows to the Dubuque WPCP, there is a need to conduct a comprehensive review of the facilities. This report reviews the condition and capacity of the existing Dubuque WPCP facilities. The evaluations address compliance with the Iowa Administrative Code updates since the facility was designed in the 1970s, and upgraded in the 1990s, including the impacts of anticipated effluent limit changes. Facilities are evaluated fora 20-year planning period, which includes anticipated treatment needs through the planning year of 2030. A specific plan for modifications to the Dubuque WPCP is recommended and supported by an evaluation of monetary costs, environmental impacts, and other nonmonetary considerations. 1.02 LOCATION OF STUDY The Dubuque WPCP provides wastewater treatment for the City of Dubuque, Dubuque County, Iowa. Figure 1.02-1 indicates the existing sewer service area for the City, and Figure 1.02-2 presents the planning area for the Dubuque WPCP facilities plan based on the 2006 Annexation Study. 1.03 RELATED STUDIES AND REPORTS The following reports were used in the preparation of this Facilities Plan. A. l/l Analysis and Project Certification, Ecology Publication No. 97-03, USEPA, May 1985. B. Wastewater Treatment Facilities Plan of Action Study, Strand Associates, Inc., January 1991. C. Wastewater Treatment Facilities Solid Waste Coincineration Report, Strand Associates, Inc., August 1991. D. Report on Annexation Study, City of Dubuque, Veenstra and Kimm, Inc., September 2006. E. Dubuque Metropolitan Area Transportation Study 2031 Long-Range Transportation Plan, East Central Intergovernmental Association, 2006. Prepared by STRAND ASSOCIATES, INC ® 1-1 RAW:pII1S:\@SAI\151--200\154\002\Wrd\Report\S 1.doc\052008 SEWER SERVICE AREA DUBUQUE WPCP FACILITIES PLAN CITY OF DUBUQUE DUBUQUE, IOWA .., ~.LI r ;~~. pp ~.: .,; -~, J I ~ ~ ~~ ~~ :, ~7 'r v~, I/~ ~t ~sk AMw~ ~ '. 'r i //'"' _ ~~ "~ it { r sc S r I 1!'~c ~`` :.~- ~ ~~ r~~ ~+ i 1 I 7 ~b ~ y~S~;_~`t I 'L ~~:ii ~ r, ~ { ,,~nrl~ i I,~ 3 v r I~ . 'r ~ I r ~ r.~ L `r ' `~~{~ ~~ ~ . I • ~~ ~4 '- ~~~. .#. ~'~~~~., ;~ _ ' ```~ _ ~~Yr ,s _ ;+~ >~ .• ~ °q, ~ ~;~~ ,~ . ~ .F; `~L~'~ x 't• ~~~ ~ ~~ . ... r _ c ~ t ?, a 'j a rt .• Y .' ~. ~ ~ f, + c 3r x; V \iq' 1 '~ ~ 1 \j, '-rs L., k _, i~; ~:. ~~ ~ . -.. - :n 4 v, it ,\ - 4 ~ y --t ~ .'St ~ ~.~ ~ _ .OJT jf'_ . ~ -^ :~ ~, r i. F Y ~~ ~S f t ,< ; ,__ --, ~ _, .. ., f _ _ - .., .. - ., s, lr ~ { - ~ ~P $ r ~ J~.~ j ,lJ~, .~ ,`' YI ~~~ .. , 1 '' ~ ~ _ - F ~f . ~` + ~f No Scale LEGEND N Q Study Area 0 New Annexation Area Source: Report on Annexation Study, City of Dubuque, 2006. Dubuque Corp. Limits 2 Mile Boundary PLANNING AREA STRAND DUBUQUE WPCP FACILITIES PLAN ASSOCIATES. INC. E N G I N E E R S CITY OF DUBUQUE DUBUQUE, IOWA F'G 154.002.2 it, City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 1-Introduction F. Flow Equalization Study, Dubuque Water Pollution Control Plant, IIW Engineers & Surveyors, P.C., March 2007. 1.04 RELATED DRAWINGS AND SPECIFICATIONS The following were used in the preparation of this Facilities Plan. A. Wastewater Treatment Facilities Phase ll, prepared by Henningson, Durham, and Richardson, Inc. Engineers, 1974. B. Water Pollution Control Plant Phase 1 Improvements, prepared by Strand Associates, Inc., 1993. C. Water Pollution Control Plant Phase 2 Improvements, prepared by Strand Associates, Inc., 1993. D. Water Pollution Control Plant Phase 3 Improvements, prepared by Strand Associates, Inc., 1996. 1.05 ABBREVIATIONS The following abbreviations are provided as an aid to the reader: avg -average BFP -belt filter press BODS -five day biochemical oxygen demand BPR -biological phosphorus removal cfm -cubic feet per minute cfs -cubic feet per second cfu/gTS -colony forming units per gram total solids col/100 mL -colonies (bacteria) per 100 milliliters CPR -chemical phosphorus removal CWA -Clean Water Act of 1972 DMASWA -Dubuque Metropolitan Area Solid Waste Agency DNR -Iowa Department of Natural Resources DO -dissolved oxygen ECIA -East Central Intergovernmental Association EPA - U.S. Environmental Protection Agency ft -feet ft2 -square feet ft3 -cubic feet gcd -gallons per capita per day GFG -green house gas gpd -gallons per day gpm -gallons per minute hp -horsepower Prepared by ST RAND ASSOCIATES, INC ® 1-2 RAW:pII\S:\@SAI\151--200\154\002\Wrd\Report\S1.doc\052008 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 1-Introduction HPO -high purity oxygen HRT -hydraulic retention time in. -inches I/I -infiltration/inflow Ibs -pounds If -linear feet max -maximum MCC -motor control center mil gal -million gallons mgd -million gallons per day mg/L -milligrams per liter (parts per million in dilute solutions) MH -manhole min -minimum mL -milliliter ML -mixed liquor MLSS -mixed liquor suspended solids MLVSS -mixed liquor volatile suspended solids mo -month MPN -most probable number NH3N -ammonia nitrogen NPDES -National Pollutant Discharge Elimination System 02 -oxygen OTE -oxygen transfer efficiency P -phosphorus pcd -pounds per capita per day PE -population equivalent PI -plant efFluent PS -pumping station PSA -pressure swing adsorption ppd -pounds per day (or Ib/day) psig -pounds per square inch gauge POTW -publicly owned treatment works RAS -return activated sludge RW -raw wastewater SCADA -supervisory control and data acquisition scfm -standard cubic feet per minute SOR -surface overflow rate SOTE -standard oxygen transfer efficiency SRT -solids retention time SS -suspended solids SSES -sewer system evaluation survey SWD -side water depth TDH -total dynamic head TKN -total Kjeldahl nitrogen TN -total nitrogen TP -total phosphorous Prepared by STRAND ASSOCIATES, INC ® 1-3 RAW:pII1S:\@SAI\151--200\15410021Wrd\Report\S 1.doc\052008 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 1-Introduction TPAD -temperature phased anerobic digestion TPRS -thickened primary sludge TS -total solids TSS -total suspended solids (or SS) TWAS -thickened waste activated sludge µg -micrograms µg/L -micrograms per liter (parts per billion in dilute solutions) UV -ultraviolet light VFD -variable frequency drive VPSA -vacuum pressure-swing adsorption VSS -volatile suspended solids WAS -waste activated sludge WPCP -Water Pollution Control Plant-City of Dubuque WWTP -wastewater treatment plant WWTF -wastewater treatment facility Prepared by STRAND ASSOCIATES, INC ® 1-4 RAW:pII1S:\@SAI\151--200\154\0021Wrd\Report\S 1.doc\052008 SECTION 2 EXISTING WASTEWATER CONVEYANCE FACILITIES City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 2-Existing Wastewater Conveyance Facilities 2.01 BACKGROUND The purpose of this facilities plan is to develop a 20-year plan for the treatment plant. A separate study, which investigates the collection and conveyance facilities, is being conducted simultaneously by the City with another consulting firm. That study includes collection system monitoring and modeling and will develop projections of infiltration/inflow (I/I) in the entire collection system as well as within subbasins of the collection system. The purpose of this section is to develop gross projections of I/I in the collection system as needed to plan for peak flow management at the Dubuque WPCP. 2.02 INFILTRATION/INFLOW EVALUATION A projection of I/I was developed for the January 1991 Plan of Action Study for the wastewater treatment facilities. This report indicated significant I/I in some parts of the collection system when the Mississippi River stage is high. The I/I components for this report were projected based on flow records from 2002 through September 2007. The methodology used is described in Section 4. Peak hourly I/I was determined from peak hourly flow which was projected based on the Iowa Department of Natural Resources (IDNR) code. The I/I components were projected as follows: Average Dry Weather Flow: 6.50 mgd (including dry weather I/I) Average Annual Flow: 7.86 mgd Average Wet Weather Flow: 10.45 mgd Maximum Wet Weather Flow: 22.22 mgd Peak Hourly Flow: 35.84 mgd Average Annual I/I: 1.36 mgd Average Wet Weather I/I: 3.95 mgd Maximum Wet Weather I/I: 15.72 mgd Peak Hourly I/I: 29.34 mgd Per capita flow rates were projected (refer to Section 4) to determine whether excessive I/I exists in the collection system. The average dry weather, average annual, average wet weather, 7-day maximum, and maximum wet weather per capita flows for 2002 to September 2007 (see Table 4.03-1 for populations used) are presented below (industrial and hauled waste components were subtracted from total flows): Average Dry Weather: 97 gcd Average Annual: 120 gcd Average Wet Weather: 165 gcd 7-Day Maximum: 207 gcd Maximum Wet Weather: 370 gcd Prepared by STRAND ASSOCIATES, INC.® 2-1 RAW:pII1S:1@SAI\151--200\154\002\Wrd\Report\S2.doc\052008 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 2-Existing Wastewater Conveyance Facilities The average dry weather per capita flow of 97 gcd is less than the EPA nonexcessive infiltration guidance value of 120 gcd. The EPA nonexcessive inflow guidance value of 275 gcd for average wet weather flows is also higher than the 165 gcd projected. The maximum week per capita flow was projected at 207 gcd and is also below the 275 gcd guidance value. Based on these comparisons, I/I does not appear excessive. However, the City is conducting a separate study to evaluate I/I that will address these issues. Prepared by STRAND ASSOCIATES, INC ® 2-2 RAW:pII1S:\@SAI1151--200\1541002\WrdlReport\S2.doc\052008 SECTION 3 EXISTING WASTEWATER TREATMENT FACILITIES City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 3-Existing Wastewater Treatment Facilities 3.01 BACKGROUND The City of Dubuque operates a secondary wastewater treatment plant that discharges to the Mississippi River. The majority of WPCP facilities were constructed in the 1960s and 1970s. The last major revisions to the WPCP were completed in the 1990s. A site plan of the existing facility is shown in Figure 3.01-1. This section presents a summary of the existing process and equipment as well as a review of the facility performance from January 2002 through September 2007. 3.02 DESCRIPTION OF EXISTING FACILITIES A. Historic Development of the Dubuque WPCP Site The City of Dubuque has operated a wastewater treatment facility at the site of the current Dubuque WPCP since approximately 1969. The original facility employed preliminary and primary treatment, followed by trickling filtration. Sludge was dewatered with vacuum filters and then incinerated. Clarifiers at the old plant were utilized for clarifying the trickling filter effluent, with sludge pumped from the old plant site to the head end of the new facilities. In 1973, the grit removal tanks, primary tanks, and trickling filters were covered, and an exhaust air odor scrubbing system was installed. In 1975, the biological treatment facilities were expanded to include pure oxygen activated sludge and final clarifiers downstream of the existing trickling filters. At that time, waste activated sludge (WAS) thickening and heat treatment (Zimpro) facilities were also provided. A belt filter press was installed in 1983 to improve the solids dewatering capability. Six WAS thickening centrifuges were installed in 1969. Four units were replaced in 1990. From 1993 through 1996, three phases of improvements were made to the plant. Phase 1 included the addition of new mechanical bar screens and screenings conveyors, a vortex grit removal system, new primary sludge pumps, an ash dewatering pad, and improvements to the sludge incineration system. The Zimpro sludge conditioning system and vacuum filters were decommissioned and removed. Two new dewatering centrifuges were installed to dewater sludge prior to incineration. Phase 2 improvements included the addition of chlorine contact tanks, a magnesium bisulfate dechlorination system and mixing chamber, and new final clarifier equipment. In 1996, Phase 3 improvements included final sludge pumping station improvements and new RAS pumps, various structural repairs, electrical upgrades, and a new Supervisory Control and Data Acquisition (SCADA) system. B. Existing Dubuque WPCP Facilities The existing Dubuque WPCP is located in the southern part of the City of Dubuque near the Mississippi River. The existing facilities were designed to meet the effluent limitations contained in the City's National Pollutant Discharge Elimination System (NPDES) permit. Table 3.02-1 summarizes current NPDES permit limitations. Prepared by STRAND ASSOCIATES, INC ° 3-1 RAW:ebt\S:\@SAI\1 51-20 011 5410 02\WrdlReportlS3.doc\052708 1 ^ra Y `"A.,~rYY11Fth "'•..ti"'.. Aye.,....... A., ~fYwh '"'" .~ "t4n;n~ ~~`°~ 1111~ ~N I 3Y k (~ . i ~~ ~~ ~"~`~,.: ~~ PRIMARY SLUDGE IN-PLANT WASTE ~~ STORAGE TANKS PUMP STATION i ~T~~~,~ •,~~ PAINt~RY _` CURIFIEAS ~~~ "r"~ .; ~ y~~.~. ~~ ..~~. ~ ND. 1 I ND, 2 J 1 r~,, ~.,t d `, ~~~~; ., BUILtlING ._~ ~"" ~ '~ f Nd. 3 `J ~%" !PRIMARY WAS \ / .'~/~ SLUDGE AND STORAG ~` ~"'w-~~~~ .' J~ SCUM TANK ~P/ PUMPING ,,,J~ J / STATION „L GRIT ~'~^ ~;.~.......a..U BASINS /" r •'`^."~i;""'+wan,l,ry"',+•,.. ~,:,.~^^w"'~ei~n"g war„~hawu~".°.'%"rd>!'J"°~"~"`~~-~~ ~ ~~ °.t..""MS.j~gir M~.f~n~fi1P10..w4aa~~rl~NN «.1 ,+'-'•"'~~ ' '`-`+•~` K~ ASH D~VATERING ,r^'"'~ ~)~I TRICKLING 11LTER ~ MAINTENANCEAND N0, 1 DECHL'ORINATION (OUT OFSERVICE) ~ 5PI,ITTER_ WAS BLDG I~ANNDLE ;"' PUMPS .~ ND:~,2.-.... _..~ f~~~~`~ ~ MANHOLE P-B ~y l 1'RICK4ING FILTER INT~RMEOIATE ND, 2 L[FT~ 5rnpoN ~ ~ ~ ~y~.~ (OUT OF SERVICE) BUfILDfNG ~ I;((NHi ....~ J v ~ ",. ..-. 1 ACTIVATED SLUDGE TANKS ~.__.~~ ND~ 3 r__._ RAS PUMP STATION ~ ' '~~ ~ ~ >' r S ~ ~ti +,~Nf ,J; ~ ~ ~~2 ~, - N0. 3 + IC1 ND, 4 DECHLORINATION BASIN HI ~.a~i~)f•waaa-~hnM 1!I'.IpMayi•wn~r ~nwnlnr MIXWG GHAUOER LAGOON . ~_._. ..v/' M' +~ ~~ ~! i ~; a J W H z W a J d H W ,~-, ~ 3 Imo ~~~ ~~~ 3F~ ~ ~ 0 N STRAND NO SCALE A68tlCIA7E5; INCi HNGINE6pB FIGURE 3.01.1 1.154.002 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 3-Existing Wastewater Treatment Facilities .__. _... ____.__.w_ _~ . ~. _._~ __~_~~. - -~.-__ ~ ~-_~~~_, Monthly Average -. ~_ -_._____m__.____ _ __ _...~_ . ~ Weekly Average ~___~~ _.m~~_-__ - ----- --- -_._ _ _ _-__.~ Parameter (mg/L) (mg/L) Maximum CBODS" ; TSS I _ 30 _ -- 45 . ~~__,,,,, .,___ _4w_ ~ ~-_ ~~__d..~ _.~.....~ ~.--- --s v___--_~a ...._n_.» _.,w_M_~_~ ~ __ ~_ » ~_ ~ _..,,_,__.__..~ _ _ ~_ _ . - __~_ _x__ _~~~_: pH,_Std. Units (Range) _LL 6 0 9 0 -- a-- -- -- -~ -~ - ~ -~ Chlorine, Total Residual° 151 µg/L __ ~._ _ - 202 µg/Ld Fecal Coliform~ 200 col/1.00 mLd__.__~ _ a Taken from WPDES Permit dated July 14, 1998. Permit expired July 14, 20 03, but has not been reissued by the DNR. b 85 percent removal required. Seasonal disinfection required April 1 through October 31. d Daily maximum. Table 3.02-1 Existing Effluent Limitationsa, City of Dubuque, Iowa The average daily dry weather and wet weather design flows for this facility were 13.39 and 17.32 mgd, respectively. The maximum wet weather and peak hour design flows were 23.24 and 34.28 mgd, respectively. The design average five day biochemical oxygen demand (BODS) loadings used for the Phase 1 through Phase 3 WPCP upgrades in 1993 to 1996 was 24,400 Ibs/day. Figure 3.02-1 shows a schematic layout of the existing facilities based on the current operating mode of the facility. Table 3.02-2 summarizes the unit sizing for the existing treatment processes. Raw wastewater is received through the Catfish and Terminal-Cedar force mains. The flow from each line is metered by a magnetic flow meter and sampled. Following metering, the wastewater flows through two mechanical bar screens and two vortex grit removal basins and then flows to the primary clarifiers. In-plant recycle flows including centrate and primary sludge storage tank supernatant are pumped to the channel just downstream of the mechanical screens. Hauled waste also enters the plant at this point. Primary effluent bypasses the trickling filters and flows to the splitter box upstream of the aeration tanks. The flow then continues by gravity to the high purity oxygen (HPO)-activated sludge system for biological treatment. Mixed liquor (ML) from the activated sludge system flows to the final clarifiers where solids are settled and removed. Return activated sludge (RAS) is pumped to the splitter box upstream of the HPO activated sludge system. WAS solids are pumped from the RAS line at the splitter box to the WAS aerated storage tanks for storage prior to sludge processing. Clarified effluent from the final settling tanks flows to a chlorination mixing chamber where liquid chlorine solution is added for disinfection. The chlorinated effluent flows through a pipe to the chlorine contact tank and then to the sodium bisulfate mixing chamber. Magnesium bisulfate is added at the Prepared by STRAND ASSOCIATES, INC ® 3-2 RAW:ebt1S:\@SAI1151-200\154\002\W rdlReportlS 3.doc\052708 LEGEND: SB - SPLITTER BOX PS - PUMP STATION SPS - SLUDGE PUMP STATION WASTEWATER FLOW --~~ SLUDGE OR GRIT FLOW RECYCLE FLOW GRIT & PRIMARY SCREENINGS--~ -- ~ a~ CLARIFIEf TO LANDFILL VAULT MECHANIC SCREENS FACILITIES PRIMAf CLARIFI PRIMARY CLARIFIER ~ SPS SB SB FUTURE`S ;PRIMARY ~ `~LARIFIEf~ ,__ ' ~~ I ' a~ ~Q z~ HAULED IN-PLANT CENTRATE AND SUPERNATANT WASTE WASTE PS PRIMARY SLUDGE STORAGE TANKS ---,, ~~TRICKLING~~ FILTER '~~ I~ (OUT OF ~IJ ~~~SERVICE~~' UNCT BOX ---,, ~~TRICKLING~~ ~` FILTER '~~ I~ (OUT OF ,~~ ~~~SERVICE~~' -- SPS SPS RAS 9--- _a~ _ . _- -- - -f6~ OXYGEN ACTIVATED SLUDGE TRAIN C FINAL FINAL CLARIFIER CLARIFIEf ~-SPS Sg TRAIN B SB TRAIN A FINAL LARIFIE FINAL ARIFII WAS BLEND ~,y___v SPS ~- ~N K SPS ~- CENTRIFUGES SPS INCINERATORS DECANT PS ASH SLURRY WAS AERATED STORAGE TAN K ASH PONDS ASH RESIDUAL TO LANDFILL MAGNESIUM BISULFITE- DECHLORINATION MIXING CHAMBER - CHLORINE MIXING CHAMBER V F = d ~ = W W V ~ ~ ~ fA ~ ~ ~ e ~ ~ ~ a ~ W LL p d d 0 ~ 3 ~ t7 Z W J PLANT EFFLUENT TO MISSISSIPPI RIVER STt~A~ ASSOCIATES, INC ENGINEER 6 FIGURE 3.02.1 1-154-002 e: S:A~SAI\151--2D0\154\002\Acad\FIG.3.02-l.dwg Time: Oct 18, 2007 - 10:59am City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 3-Existing Wastewater Treatment Facilities TABLE 3.02-2 DUBUQUE WPCP EXISTING FACILITIES Design Parameter Value Flows and Loading Average Dry Weather, mgd 13.39 Average Wet Weather, mgd 17.32 Maximum Wet Weather, mgd 23.24 Peak Hourly Flow, mgd 34.28 BOD, Ib/d 24,400 TSS, Ib/d 24,600 Mechanically Cleaned Bar Screens No. of Units 2 Rack Size 3-ft 6-in width, 3/4-in opening size Type Climbing Rake Mechanism Capacity 20.0 mgd (each unit) Controls Level and timed actuation Grit Removal Number of Units 2 Type Vortex Capacity 34.3 mgd, each Grit Pumps Number 2 Type Recessed Impeller Motor 15 hp Primary Clarifiers No. of Units 3 Type Circular Diameter, ft 90 Side Water Depth, ft 9 Total area, ft2 19,100 OverFlow Rate, gpd/ft2 @ 40.0 mgd 2,100 Trickling Filters, Out of Service No. of Units 2 Diameter, feet 195 Intermediate Lift Station Trickling filter effluent pumps, out of service 3 @ 14,000 gpm WAS pumps No. of Units 2 Type Centrifugal Capacity 250 gpm each Prepared by Strand Associates, Inc.® Page 1 of 5 RAW:pII\S:1@SAI\1 51-20 011 54\002\Wrd\Report\Table 3.02-2.doc\052208 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 3-Existing Wastewater Treatment Facilities Design Parameter Value High-aurity Oxvclen Activated-Sludge Tanks Number of Trains 3 Number of Tanks/Train 3 Tank Length, ft 90 Tank Width, ft 26 Side Water Depth, ft 12 Aerators/Tank 3 Aerator Horsepower (each train), hp Tank 1 30/10/7.5 Tank 2 5/5/5 Tank 3 7.5/10/15 Design BOD Load, Ib/1,000 ft3/day 97 Design HRT @ 13.39 mgd, hrs 3.4 Oxygen Storage Liquid Storage Capacity, tons 44 Vaporization Capacity 22.8 tons/day Final Clarifiers No. of Units 4 Type Circular, floc center well, siphon collector, Stamford Baffle Diameter, ft 105 Side Water Depth, ft 12 Volume, ft3 Each 103,920 Total 415,680 Overflow Rate, gpd/ftft2 @ 13.39 mgd 386 @ 17.32 mgd 500 @ 34.28 mgd 990 Weir Length, ft Each 312 Total 1,248 Weir Loading Rate, gpd/ft @ 17.32 mgd 13,880 Effluent Disinfection Type Chlorine gas dissolution, ton cylinders Chlorine mixing chamber Number 1 Mixing Mechanical, 10 hp Chlorine Contact Tanks Number 2 Volume, cu ft Each 24,150 Total 48,300 Detention Time, min @ 17.32 mgd 30.0 Prepared by Strand Associates, Inc ® Page 2 of 5 RAW:pII1S:\@SAI\151-200\154\002\WrdlReportlTable 3.02-2.doc\052208 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 3-Existing Wastewater Treatment Facilities Design Parameter @ 34.28 mgd Length to Width Ratio Effluent Dechlorination Type Dechlorination Mixing Chamber Number Mixing Feed Pumps Number Capacity, gph (each) Chemical Storage Tanks Number Volume (gallons) Value 15.2 40:1 Magnesium bisulfite solution 1 Mechanical, 10 hp 2 11 2 2,500 Primary Sludge Pumps No. of Units Type Capacity, each Controls Primary Scum Pumps No. of Units Type Motor Primary Sludge Holding Tanks No. of Units Size, each Total volume Covers Primary Sludge Transfer Pumps No. of Units Type Capacity Returned Activated Sludge Pumps No. of Units Type Capacity, gpm Motor Secondary Scum Pumps No. of Units Type Motor 3 Air-operated diaphragm 76 gpm Time Operation 3 Progressive Cavity 15 hp 2 35-ft x 35-ft x 16-ft SWD 293,000 gallons Fiberglass cover system 3 Progressive cavity 175 gpm each 6 Fairbanks Morse, centrifugal, variable speed 3,000 @ 31-ft TDH 40 hp 2 Self-priming centrifugal 5 hp Prepared by Strand Associates, Inc ® Page 3 of 5 RAW:pII\S:\@SAI\151-200\154\0021Wrd1Report\Table 3.02-2.doc\052208 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 3-Existing Wastewater Treatment Facilities Design Parameter Value NPW Pumps No. of Units 3 Type Centrifugal, horizontal split case Capacity 600 gpm @ 180-ft TDH Motor 50 hp Control Manual WAS Gravity Thickener (Out of Service) No. of Units 1 Size 26.5-ftx 26.8-ftx 8-ft SWD WAS Storage Tank (Out of Service) No. of Units 1 Volume 4,450 cu ft (33,300 gallons) WAS Thickening Centrifuges (Out of Service No. of Units 4 Capacity, each 60 gpm Solids Capture 90 percent Solids Capacity, Each 65,00 Ib/day at 1 percent WAS Solids Capacity, Firm 19,500 Ib/day for 3 units Thickened WAS Storage (Out of Service) No. of Units 1 Volume 2,500 cu ft Aerated WAS Storage No. of Units 1 Size 55 ft x 80 ft x 14.25 ft SWD Volume 62,700 cu ft 469,000 gallons Aeration Blowers 3 @ 1,100 scfm; 75 hp each Aeration Blower Type Centrifugal Aeration Diffusers Coarse bubble Dewaterina Centrifuges No. of Units 2 Type High-speed Expected Cake Solids 27.5 percent Expected Solids Capture >90 percent Feed Capacity, Each 150 gpm (Primary and WAS) 100 gpm (Primary and TWAS) 1,200 Ib/hr dry solids (Primary and WAS) 2,100 Ib/hr dry solids (Primary and TWAS) Dewatering Belt Press (Out of Service) No. of Units 1 Use Standby to centrifuges Prepared by Strand Associates, Inc.® Page 4 of 5 RAW:pII\S:1@SAI\151-200\1541002\Wrd\Report\Table 3.02-2.doc\052208 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 3-Existing Wastewater Treatment Facilities Design Parameter Capacity Value 1,400 Ib dry solids/hr Incinerator Feed Pumps No. of Units Capacity, Each Type Fluidized Bed Incinerator No. of Units Dimensions Bed Diameter (I.D.) Freeboard Diameter (I.D.) Freeboard Height (I.D.) Exhaust Temperature Feed Rates (with Recuperator) @ 27.5 percent sludge cake solids sludge feed rate @ 30 percent sludge cake solids sludge feed rate Fluidizing Air Blowers Air Pollution Control 2 7.5 wet tons/hr Positive displacement (1 Prog. Cav., 1 Reciprocating Piston) 2 11ft 18ft 15ft 1,600°F 5.5 wet tons/hr 5.6 wet tons/hr 2 @ 6,000 scfm each Venturi Scrubber (1/unit) Packed Scrubber (1/unit) Incinerator Recuperator-North Incinerator No. of Units Temperature Profile Inlet Combustion Air Outlet Combustion Air Inlet Exhaust Gas Outlet Exhaust Gas 120°F (Blower discharge) 900°F 1,600°F 1,100°F Prepared by Strand Associates, Inc.° Page 5 of 5 RAW:pII1S:1@SAI\151-200\154\002\WrdlReport\Table 3.02-2.doc\052208 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 3-Existing Wastewater Treatment Facilities discharge of the chlorine contact tank to remove the chlorine. Following dechlorination, effluent flows by gravity to the Mississippi River. Primary sludge is pumped to two primary sludge storage tanks. Primary sludge and WAS are blended in a small blending tank and pumped to the centrifuges for dewatering. The sludge cake is then pumped to one of the incinerators and the centrate is recycled to the plant. Incinerator ash and scrubber water are pumped to the ash storage lagoons at the east end of the plant. Ash lagoon decant is discharged to the in-plant sewer and recycled to the front of the plant downstream of the screens. Current practice is to operate the centrifuges four to five days per week, 18 to 20 hours per day. The north incinerator is normally in operation since it has a dedicated recuperator and is significantly less expensive to operate. The north incinerator is typically operated four days per week. The south incinerator has a lower throughput capacity and is typically operated five days per week when in operation. 3.03 INFLUENT FLOWS AND LOADINGS A. Influent Flows All of the influent flow is pumped to the WPCP through the Catfish and Terminal-Cedar force mains. Plant flow is measured upstream of the mechanical screens with two magnetic flow meters. Flow records for average daily flow from January 2002 through September 2007 are presented in Table 3.03-1. These values are monthly averages of average daily flows. The 13.39 mgd design value was not exceeded on a monthly basis in the period of record. Monthly Average Daily Flows (mgd) Month 2002 2003 2004 ~ 2005 2006 2007 January 744 6 6 604 7 153 7 010 ( 7 170 _. ~ 7 187 _ _ February - _ __ . _._r U 7 015 __e __ _ ___ __ 6 583 .~ .~ ~- _ _ _ x_, 7 390 _ .. __ _ 8.126 7 020 _ 1 7 225 March 7 305 6 647 ~ 9 203 _ 7 459 ~ __ 7 935 ~ 8 732 _~. ,_Apnl _ ( 8 453 ~ 7 460 ~ _ 8_028 _ 8 071 rc 10 113 10 635 _ May _ _ ~ 8 382 ~ _~- 9 149 u 8 985 - ~ - 7 349 e--- _ 9 533 -~ __ 7 740 June_ 9 570 _ 7 060 10 359 7.301 _ 7 998 7 147_ _ _ July - _ 7 644 ~_ 7 671 _ _ __ 7 826 ~ 7 072 - 8 591 ~ ~ ~ - 8 191 - r. August _ 7 $ ~ 5 6 964 6 983 7 203 7 688 ~ 9 342 . __._, September -__ . . _~_ __. ._~_ ~ 7 553 .. ~~u. _. _ 7 141 =__ __ --- 6 857 ~ .~ -- - - 7 251 I --- _=_ 8 154 ~_._.m _..~ .._ 7 651 October 8 518 6 893 6 916 7.126 7 100 November _~. .. __ 7 058 ~,__ , _ ,._ .__. 8.613 .,. _ ,.~~. 7 017 _. __. ~~.__~ ._~~_. 6 961 . ,__ ~___,__.~ __ 7 138 _~em ___n.v... _-~ __ _ . _.. _,_ December 6.624 7.692 6.872 ~ 6.865 7.484 Annual Average 7.723 _ 7.373 ~ 7.799 7.316 7.994 8 205 1. Annual average flows are the average of the monthly average daily flows. Table 3.03-1 Average Daily Flows (2002-2007) Prepared by STRAND ASSOCIATES, INC.® 3-3 RAW:ebt\S:\@SAI\151-200\154\002\Wrd\ReportlS3.doc\052708 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 3-Existing Wastewater Treatment Facilities On a daily basis, the 13.39 mgd design average dry weather flow was exceeded 22 times from 2002 through September 2007 with an estimated maximum daily flow of approximately 27 mgd. Based on these flow records, the design average flow of 13.39 mgd was exceeded about 1.0 percent of the time, and the average wet weather flow of 17.32 mgd was exceeded four times. The flow exceeded the current facility maximum wet weather flow value of 23.24 mgd only one time from 2002 to September 2007. A daily flow of 27.05 mgd was recorded on June 4, 2002. A peak hourly flow of 33.6 mgd was observed in July 2007. Figure 3.03-1 graphically depicts total daily flow from January 2002 through September 2007. 30 25 -- 20 - E - 3 15 - - - - - c c 5 - 0 Jan-02 Jan-03 Jan-04 Jan-05 Jan-06 Jan-07 Date Figure 3.03-1 Total Daily Flow from January 2002 through September 2007 B. Influent BODS and TSS Loadings Tables 3.03-2 and 3.03-3 summarize influent GODS and total suspended solids (TSS) loadings. Values contained in these tables are based on average monthly loadings. Figures 3.03-2 and 3.03-3 summarize daily values for BODS and TSS. I~ I~ Prepared by STRAND ASSOCIATES, INC.° 3-4 ~ RAW:ebt\S:\@SAI\151--200\154\002\WrdlReport\S3.doc\052708 I i__; City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 3-Existing Wastewater Treatment Facilities Monthly Average BODS Loads (Ib BODS/day) ~ _ Month ~ 2002 ~ 2003 -- 2004 2005 2006 ~ - 2007 - Janua ~ 20,449 -~ 18 061 16,346 - _ 14 915 ___ - 20,521 . _ 18,173 _______ ,,yFebruary ... ._____18,756 _ ~__ 18,632___,._y ~_16,484__~__ µ15,574 ~ _ 18,529_,y 17,975- ,__ March 20,057 ~ 17,947 16,543 15,010 ~ 18,077 16,259 _x____ _~ __ Apnl - __ _ _ __ 19,119 ~_ 16,935 _ 15,885 16,763 17,439 17,099 May _ _,_- ___ 18,921 __ 16,658 . __ 14,764 _~._._a~~._ _r_ -~ 15,618 ..__a~.~ 17,835 ~~~_ 16,384 _ v June 18,643 16,247 14,504 ~ 15,861 18,225 15,253 _ - ~.,_ JuIY_ __ -_- 16,638 ~ , 15,319_.__.: __ ___13,806 ,_ _~ m .__.16,643.___. ~._~-17,603 ___ _ ~ ..-..__ _~=._n____ August _ _ 16,160 __ u __ „ 16,229 __, _ _ 14,877 - 14,920 - 17,419 ~- ~~_.-~ September w _ __16,893 _ 16,139 _ _.. 14,131 __ w _ 17,637_ _ 17,285 _,__ _ October 18,006 16,773 15,234 16,667 17,877 November _ 18,491 17 904 ~ 16,025 - 18, _069_ ... ~ _ 091 16~ December ----- - =rr~__ .~. ~ 17,860 ~.~_~._ ~~ ___ 18,024 ~ --_.a.KK__ ~ 16,001 _ ~ 19,123 18,915 - _ __- -- ~~~.~ ~- - - -- Annual Average , _ 18,333 17 072 15,383 _16,400 A_____ 17,985 _ _ 16,857 _ _...---~ ~ - -- .yv_-_. ~ __ _~ _..__ . ,_ _--- -~ ~ -- -~..-__.~Y R~ __~ ._ __- - _ 1. Annual average loadings are the average of the monthly average daily loadings. Table 3.03-2 BODS Loadings (2002-2007) M onthly Average Dally TSS Loadings (Ib SS/day) ,, Month _ ~ 2002 ~ 2003 ~ 2004 2005 _ ~ 2006 _ 2007 - --- January - _ 12,180 ~ _ 11,366 _ 9,831 ~~u_ ~. 9,417 12,595 . 10,717 _ _ February - -.r_~r~ _ _~- _ _ __,10,590 I .,._.~_._.r.___. 13,332 _~ _ ___ ~_--~ 10,700 ---- - -- 11,567 - -- 10,876 10,403 __ March 11,653 ~ 10,923 10,260 9,786 11_,991 10,721 -_: April___~ _ ~ 11,935_ _ _ 11,602 10,203 _ ._. 9,831 _Y__ 11,513___ _r_1-3,252 __~ May __,_11,290 ,__ -,____µ1O,422 _ [ -, 12,462 u 10,133 ._._. __ _ ~ ~_ ~ 10,803 = _,10,709 w_ ~ June _ 15,478 ___ _10,544__ _ ,12,373 . 10,767 ._ -_ _ 14,853 __ r ~ 10,560 _„ p July __ _ _-~m ~__ 12,072 _ 10,146 10,802 12,468 I 12,439 August _ 12,938 ~ 9,688 10,653 14,171 11,534 _ September 11,514 _ . __ - -- u ___10,019_._ __, _9,722____,_. A__15,559 __ ___v12,108_ _ _ __a _ ~__ ~_.~.. October ~ 11,513 ~ 10,220 _ 11,379 - 10,958 ______ _ _ 810,287 _ ~n _ _. e _ s November 12,003 ~ _-.., e.__-_ .._ - _ 11,912 10 689 - 11,858 _ ___ 9,155 _~~. ~__~~ _._, December _ 10,703 _ 10,537 ~ ~ 10,071 10,.552 ~_ 11,458 ~. - r-_.-__-. ___-a~F Annual a~,~..T__.~ ._ _ _ Average_ 11,993 867 10, 10,766 11,420 _ _ 11,637 __...___. _ _11,062 ---_-_ 1. Annual Average Loadings are the average of the monthly average daily loadings. Table 3.03-3 TSS Loadings (2002-2007) Prepared by STRAND ASSOCIATES, INC.® 3-5 RAW:ebt\S:\@SAI\151-200\154\002\WrdlReport\S3.doc\052708 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 3-Existing Wastewater Treatment Facilities I 45000 40000 --- - - ~ 35000 --- - - - --_ O 30000 - m -- ---- - v M 25000 - - - G1 C - - -- ~ 20000 O J - -- p 15000 O m 10000 - - - - 5000 Jan -02 Jan-03 Jan-04 Jan-05 Jan-06 Jan-07 Date Figure 3.03-2 Summary of Influent BODS Daily Loadings 90000 80000 - - 70000 -- --- 60000 ~ 50000 - - - - -- 40000 - -- - -- N 30000 --- F - ---- -- - 20000 --- - 10000 0 Jan-02 Jan-03 Jan-04 Jan-05 Jan-06 Jan-07 Date Figure 3.03-3 Summary of Influent TSS Daily Loadings Prepared by STRAND ASSOCIATES, INC.® 3-6 i RAW:ebt\S:\@SAI\151--200\154\002\Wrd\ReportlS3.doc\052708 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 3-Existing Wastewater Treatment Facilities From 2002 to June 2007, the total BOD and TSS loadings averaged 16,993 and 11,291 Ib/day, respectively. The design BOD and TSS loadings for the existing plant are 24,400 Ib/day and 24,600 Ib/day, respectively. Therefore the plant design loadings have not been exceeded, and the plant is loaded at about 70 percent of the BOD capacity and at about 46 percent of the TSS capacity (excluding in-plant waste recycle streams). Loadings from industrial sources accounted for about 38 percent of the BOD and 14 percent of the TSS loadings. The majority of the BOD/TSS industrial loading is contributed by three major industries. These are Inland Protein (IP), Swiss Valley Farms (SVF), and Rousselot (ROS). ROS discharges about 55 percent of the industrial BOD load (3,588 Ib/day) and about 36 percent of the industrial TSS load (574 Ib/day). IP and SVF each contribute about half of the remaining loads. Because of the soluble, high-strength industrial loadings, the influent wastewater BOD is more soluble than most municipal wastewaters. For most WWTP influents, the average TSS loading is marginally greater than the average BODS loading. However, the influent data for the Dubuque WPCP indicates that the average TSS loading is approximately 6,000 to 7,000 Ibs/day less than the average BODS loading. The soluble nature of the industrial loadings (measured at the respective industrial discharge locations) account for approximately 4,000 to 5,000 Ibs/day of the noted difference. However, the remaining difference cannot be accounted for unless there is a consistent sampling error that underestimates TSS (as well as the BODS associated with those solids) in the influent wastewater. There is reason to believe that TSS and BODS concentrations are consistently underestimated. The following observations appear to support this hypothesis: 1. Based on plant records since 2002, the amount of primary sludge generated (see Section 3.06) would require an average primary clarifier TSS removal efficiency of 96 percent to achieve the amount of primary sludge from the measured influent TSS loadings (including an allowance for in-plant waste recycle loadings). This removal efficiency is significantly above the more typical 65 to 70 percent TSS removal efficiency observed in primary clarifiers. 2. Based on plant records since 2002, the average measured primary clarifier TSS removal efficiency [(influent TSS-effluent TSS)/influent TSS; including an allowance for in-plant waste loadings] is only 53 percent, which is significantly lower than typical 65 to 70 percent. 3. Based on plant records since 2002, the average measured primary clarifier BODS removal efficiency [(influent BODS-effluent BODS)/influent BODS; including an allowance for in-plant waste loadings] is less than 5 percent. Typical primary clarifier removal efficiencies are in the range of 25 to 35 percent. 4. Based on our analyses (Section 4), the projected per capita TSS loading (not including industrial loadings) since 2002 is only 0.16 Ib TSS/person/day. This value is less than the per capita BODS loading of 0.18 Ib/person/day, which is atypical for municipal wastewater. In addition, the calculated per capita TSS loading is Prepared by STRAND ASSOCIATES, INC ® 3-7 RAW:ebt1S:\@SAI1151-200\154\0021W rd\ReportlS3.doc1052708 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 3-Existing Wastewater Treatment Facilities significantly less than the expected value of approximately 0.20 to 0.25 Ib TSS/person/day (industrial loadings not included). Based on these observations, we believe that the influent TSS loadings may be underestimated by as much as 40 percent, and the resulting BODS loadings are underestimated by 25 to 30 percent. If the TSS and BODS loadings are underestimated as noted above, the plant monitoring data correlates very well with the sludge quantities generated. An explanation for this potential sampling error follows. The Dubuque WPCP has two separate force mains discharging to the headworks. Each force main is tapped with a small diameter pipe, and raw, unscreened wastewater is pumped with small centrifugal pumps to the sampler. Because the wastewater is unscreened at the point of sampling, there is a reasonably good chance that the sample piping could be plugged and acts like a filter to remove some of the TSS in the raw wastewater. In addition, the samplers used to measure the influent wastewater strength have a dipping cup that enters the waste stream with the cup facing downstream. This could result in nonrepresentative sampling for TSS, since the mass and momentum of the TSS would tend to keep the particles moving downstream instead of laterally into the cup. Additional verification sampling is discussed in Section 5. C. Phosphorus and Nitrogen Loadings The WPCP is not currently required to remove phosphorus, ammonia nitrogen, or total nitrogen. As part of this planning effort, the plant collected limited primary effluent phosphorus and total Kjeldahl nitrogen (TKN) data during the spring and summer of 2007. In addition, ammonia nitrogen is monitored in the plant effluent and those results are shown in Table 3.05-3. Primary effluent phosphorus concentrations ranged from approximately 3 mg/L to 40 mg/L, with an average of about 10 mg/L. Primary effluent TKN values ranged from approximately 60 mg/L to 72 mg/L, with an average of 63 mg/L. Both of these values are approximately 50 percent higher than typical medium-strength municipal wastewater, which corresponds well with the influent BODS and TSS concentrations and the high-strength industrial loadings. 3.04 IN-PLANT WASTE LOADINGS Section 3.02 briefly described the operation of the sludge handling system. Primary sludge and WAS are pumped to separate storage tanks prior to processing. These two sludge flows are combined in a small blend tank and then pumped to the centrifuges for dewatering. The centrifuges capture approximately 97 to 98 percent of the TSS, and the remaining 2 to 3 percent are discharged to the in-plant waste pump station. Additional in-plant waste loads come from decanting the primary sludge storage tanks, decanting the ash storage lagoons, and secondary clarifier scum removal. In addition, the plant accepts minor amounts of septage. All of these flows are discharged to the in-plant waste pump station, which conveys these flows to the wastewater channel immediately upstream of the grit removal basins. These in-plant waste loadings are not measured by the influent wastewater sampler. The centrate flow represents the majority of in-plant waste flow, and projections of the additional loads Prepared by STRAND ASSOCIATES, INC ® 3-8 RAW:ebt1S:\@SAI\151-200\154\002\W rd\Report\S3.doc\052708 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 3-Existing Wastewater Treatment Facilities from the centrate are approximately 5 to 6 percent of the raw wastewater influent loadings. Therefore, the total in-plant waste flows are anticipated to account for less than 10 percent of the raw wastewater loadings. 3.05 WPCP PERFORMANCE AND PERMIT COMPLIANCE This section reviews the performance of critical forward flow treatment processes including primary sedimentation, biological treatment, and effluent disinfection. A copy of the City of Dubuque's National Pollutant Discharge Elimination Discharge (NPDES) permit is included in Appendix A. A. WPCP Performance-NPDES Permit Compliance Tables 3.05-1, 3.05-2, and 3.05-3 summarize the average monthly effluent BODS, TSS, and ammonia nitrogen concentrations from the Dubuque WPCP. Figures 3.05-1, 3.05-2, 3.05-3, and 3.05-4 display daily values for effluent BODS, TSS, NH3-N, and pH, respectively. Over the time period evaluated (January 2002 to June 2007), the plant has had occasional TSS violations and minimal difficulties meeting effluent carbonaceous biochemical oxygen demand (CBOD) limits. For example, the monthly average CBOD limit was exceeded one time from 2002 to June 2007, while the monthly average TSS limit was exceeded one month in 2003; two months in 2002, 2004, and 2006; and four months in 2005. The monthly average TSS limit was exceeded 17 percent of the time from 2002 to June 2007. Refer to Section 5 for additional discussion regarding exceedances. _ _ Effuent BODS (mg/L) _ Month ~ 2002 2003 2004 2005 2006 2007 January ~ ~ 15 13 ~ 8 ~ 12 _ __ 9 ~ 10 __ _~ _February - 8 =- T_ ____~ ~_.~ __ _. _~_.11.. a-- ~ _ 19 T -__ _ ~____~~. 9._wN,.,._ __ _.~_._ 12___- _ -_ _~ March ~ 10 ~ 11 14 9 ~ 21 15 April ~ 12 ~ _ -- 18 6 12 ~ z 17 14 _ June 16 7 ( 5 5 _ ~. 8 22 _~.. ~..» ~.___~ -__-_ __ ~ July _~_.__ ~ _.r_.__4_ 8 ~ .~ 8 _ -~ 6 _ 5 19 Au _ust 11 6 9 12 9 September 5 22 11 _ 24 8 _ October 9 s _ 6 _ 9 -_~ 19 _ 6 I _~ _ _e__ _ November 12 __ m~_~.__~ 13 _. __ _ _ .___._ __._ . 9 .. _ _~ _w_ _ , ~ 27 -__~~ .______ 6 I __,~ _. ~__. ~ _ ___ ~_~.~ _ December 11 . _ _ ~ 8 _ 16 11 7 _ Annual ~ ~ Avera9_e_ _ . _ 10- _ _ _ ._ 11 10 __13 11 _ 14 --. _ _ 1. Annual average efFluent values are the average of the monthly average daily efFluent values. Table 3.05-1 Effluent BODS (2002-2007) Prepared by STRAND ASSOCIATES, INC ® 3-9 RAW:ebt\S:\@SAI\151-200\154\002\WrdlReport\S3.doc\052708 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 3-Existing Wastewater Treatment Facilities Eff luent TSS (mg /L) Month 2002 ~ 2003 ~ 20 04 2005 ~ 2006 2007 - January -- 45 _ r~ ~ 1 20 . ~ 13 29 ~ 11 ~ _u ~ ~ 12 _._ . February 9 -- ~ tr- - 15 y 16 56 10 ~ ~ ~ 4 - March - - 18 - .. n i 16 _ 40 16 30 ~ .LL_. ~ u __ 19 April _ 18 44 ~ ~ . _ 10 19 40 19 _a._ May _ 13 21 rv_, n [ 24 7 8 _ 13 June _ _ r ~ 35 ~ 9 _ 8 _._ 6 __ .. . 12 29 __ _.. . July ~ ._ ~ ~ 14 ~ _ ? ~ . - __ _. 5 ._ . ~__ _. ._ 45 ~ __._ __ ~__s~~_ _._=__~_ August, ~~_~_.~. . _.__~._. 26 _~.._._.._ ~.__~__.. 8 _m______. __._m~._____ 12 _~,rm_„ ._~~____ _ 20 ._~n~.__ _~_____ 18 ___.__~_...___~___..._ September 6 27 19 47 15 October 14 8 11 37 8 November -. ~~_: 18 _ .. u__~n_ 22 ~..~.. .. r_~_ ._._ 10 ___ ~ tiw- _ -_~ 67 - - _~ _ 8 a~-- z_.. -~ ~.__..M_ s.~. December 13 13 36 15 ~ 10 - Annual - _ ~ -- Average. _ ~._----- ---_ 19 ~ _~___ ~ ~__~ ~__~.. 18 _~_- __~_v__~ ~ _ ~. 17 -_ ~ _ _-v_. ___ ~ 27 - ------~~ .. ~.~.. 18 .---- - ~ LL-- - ~ 18 -~ ---- -__._~.. _~___..x. 1. Annual average effluent values are the average of the monthly average daily effluent values. Table 3.05-2 Effluent TSS (2002-2007) -- ----_ Effluent A mmonia Nitrog en (mg/L) Month ~ 2002 ~ 2003 ~ 2004 2 005 2006 2007 January - 19 23 20 . 21 ( 20 ~c 19 -~ -~ _ February 19 24 __ ~m 20 19 ___ 22 18 March 20 24 ~ 16 ~ ~ 21 _ 20 17 _ April 19 20 24 _ [ 23 16 15 ._~May,M_~_. . __~_ 21,--. 25 -- - __ 20 _~ ~ , _27 ..._ _ ~ -. 15 _ -- ~ _ 27 - June _ __ 17 _. _- 22_ -- ~ „_ 1b ~ 19 i 20 25 - - _,.. July 16 ~ _ 19 ~ 15 ~ 19 16 I ~ August ~ 16 __ ~ 24 ( 23 19 . 16 September _ 18,___ _,__ 24 _ _, 21 23 _ 15 - October 16 - 23 _ ~ 21 ~ ~ 20 18 November ~ _ 24 ~_ _~~_ 28 .__ ~. ~,. ~.. _--. 24 ~ ..._. 28 . _ .,,xW... _. _k 22 ,___ ___...~_ _wu. zn~ - - December ~ 21 16 I 21 19 19 - Annual Average __.. 19...._.. -- _ 23--- -- -- 20 21 --- 18----- 20 1. Annual average effluent values are the average of the monthly average daily effluent values. Table 3.05-3 Effluent Ammonia Nitrogen (2002-2007) Prepared by STRAND ASSOCIATES, INC ® 3-10 RAW:ebt\S:\@SAI\151-200\1541002\Wrd\ReportlS3.doc\052708 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 3-Existing Wastewater Treatment Facilities 350 300 .-. J ~ 250 E p 200 O m 150 m ~ 100 w 50 0 Jan-02 Jan-03 Jan-04 Jan-05 Jan-06 Jan-07 Date Daily Effluent BOD - - - -Weekly Limit Monthly Limit Figure 3.05-1 Summary of Daily BODS Effluent Values 600 ~ I 500 .-. J ~ ~.. 400 N ~ 300 c ~ 200 i W 100 0 Jan -02 Jan-03 Jan-04 Jan -05 J an-06 Jan-07 Date Daily Effluent TSS - - - -Weekly Lunt Figure 3.05-2 Summary of Daily TSS Effluent Values Monthly Limit Prepared by STRAND ASSOCIATES, INC.° 3-11 RAW:ebt\S:\@SAI\151--200\154\002\W rd\Report\S3.doc\052708 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 3-Existing Wastewater Treatment Facilities 140 120 - - - ~ 100 - - - - ... Z 80 - M 2 Z 60 - - - - - - c m ~ ~ 40 - W 20 - - - 0 Jan-02 Jan-03 Jan-04 Jan-05 Jan-06 Jan-07 Date Figure 3.05-3 Summary of Daily NH3-N Effluent Values 10 9 i $ i 2 I ~ 7 - - ~ I I uJ 6 II 5 4 Jan-02 Jan-03 Jan-04 Jan-05 Jan-06 Jan-07 ~ Date Fi~~are 3.05~~ Summary of ®aily ~H Effluent Val~~es Prepared by STRAND ASSOCIATES, INC.° 3-12 RAW:ebt\S:\@SAI\151--200\154\002\W rd\Report\S3.doc\052708 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 3-Existing Wastewater Treatment Facilities On a weekly basis, the effluent CBOD limit was exceeded about 2 percent of the time from 2002 to June 2007. The weekly CBOD limit of 40 mg/L was exceeded five times from 2002 to June 2007, with three of those events occurring in 2005. The effluent weekly TSS limit was exceeded 17 times from 2002 to June 2007. Four exceedances were reported each in 2003 and 2005; three in 2006; two in 2004; and one in 2007. The weekly TSS limit was exceeded about 6 percent of the time from 2002 to June 2007. Refer to Section 5 for additional discussion regarding exceedances. Effluent disinfection is required at the WPCP from April 1 through October 31 of each year. The plant needs to meet a daily maximum fecal coliform limit of 200/100 mL. While the NPDES permit only requires quarterly monitoring for fecal coliforms, the plant typically monitors once per month during the disinfection season. Table 3.05-4 presents a summary of the effluent fecal coliform testing from the plant. Based on 19 samples collected over the years of 2002 to the present, the fecal coliform limit was exceeded seven times. Effluent Fecal coliform Month ~ 2002 2003 ~ 2004 2005 ~ 2006 2007 A ril _~.__.__r. p_ ___~.___ u May_.__ _. ---___ __ 1 i l ..___. _ ___ ~ .. _ __.-_. _ ~._._~. _ ~ . _~_~ ~.~~_~~_. e~__ z__.--_- -____._ ~ ~__w~.=R____-__ _ _ __-- _-~__ _w_._ - . - ___ _.__ _ -... ~-_ 1 ~._~~~__ 980 TM ~. __..._129 .~_ _.. ~-.. June 33 24.0 _..._~ ~~__.~~_80,.._~~_ _ __-----55___u ~_ ~ -~___- 480 -.n~a_~ __~.._ 109_. --__.- July ~ 110 ~ ~ 1.00,00.0 ._. mAugust = -,~ _.~__ n,~_._,._.»_~__~ ,~_.~ __..«___ _~~_..n _~ ___~» -- ---,~ r_am.=_._ _..~._~_ _..~_ ___~_~_ 172 = _ .~ __~__k_-..___.~... September .~ ~,~~.. ~~,.~,____., ..~ _~~ .~ ,T 144 _n. ~-_ _ _,123 --=_~~ ~._.tt 2,200... .. -~ 200 --- ~ _ _ - October ~ 80 - 3,000 410 180 ~ - Annual - - _ - Average ~ ----,_ _ 74 ~a p_~__ ~___ _ _192 ~ __.m___ ... _1,101y _-.~ _. _T~_._888 q~ _~ _._ ._._- 3573_. _.._ ._ ~..- 109 1 "-" Indicates no testing required. 2 Annual Average values are the average of the reported values. 3 Excludes July Table 3.05-4 Effluent Fecal coliform (2002-2007) The average monthly and daily maximum residual chlorine concentrations allowed are 151 µg/L and 202 µg/L, respectively. Table 3.05-5 presents the residual chlorine monitoring data. Based on this data, the monthly average chlorine residual limit was met each month from 2002 through the present, and the daily maximum limit was exceeded at least one day in five of the 39 months. The City of Dubuque WPCP is also required to conduct whole effluent acute toxicity testing on an annual basis. All of the tests conducted since 2003 have been passed. B. Incineration Performance-Air Permit Compliance The WPCP holds a Title V Air Quality Operating Permit (01-TV-022) for the two incinerators. Emissions limits for the incinerators are provided in Table 3.05-6, and these permit requirements have been met. Specific operating requirements are also included in the permit, and two of these requirements (minimum pressure drop across the venture scrubber > 14 inches and maximum oxygen percentage of Prepared by STRAND ASSOCIATES, INC.® 3-13 RAW:ebt\S:\@SAI\1 51-20 011 54\002\Wrd\Report\S3.doc1052708 d ~+ .v 1i C d R H rd+ 3 :: 3 C y W C O ~+ V d N ti R O d N m N d O v N ~o J " a a ~ W o ~ V W 0 Z O 0 3 d ~ ~ d .G ~ ~ Z ~ M W O 3 J J m LL ~o ~ w i-__ , ~....._..... --- _ __ _ E--- -- -._... ....._.._ ?'~ o 0 0 0 Q .X 'd' ti d' CO (Q ti ~ O N ~ ~ ~r N d' M O M ~ ~ r Q ~, X 0 0 0 0 0 0 0 . ~ 0 ti ~ M 00 (Q • x d ^ ~ ~ C 0~ p m g 0 o _ __~_ - - - ~- - N ~ ~ ~ O ~ Op N 00 I` lA N ~ O~ M N N N N ~ CO ~ Q ~' X ' ~ 0 0 0 0 0 0 0 ~ Ln r O ~ O ~ O d' p ~ ~ O .-. N ~ ~ J O .~ (0 M M M N N ~ ~ 0~ c 0 ~ Q ~ ~ ~ ~ - -- - _~-r _. _.,. _. . .. ~_._,. ~.- -~.__ a . . >' ~ ~ 0 0 0 0 0 0 0 ~ ~ M - 00 ' d' Cfl O O r ~ ~ r d ~ ~ ~ ~ ~ O ~n _ __- ~ --- -- -~... .._,_.r. ,.,._.,_ ~ U O N .._._.~~ >, a~ .f f ~ ~ ~ ~ O +-' 0 0 0 0 0 0 0 ~ ~ QJ M d' d' N M N M ~ Q W 3 _,__. . __..~. . [ ~_... _.. .-._ ._~ ~ ~R_~ ~' E ~ 'X o M o N o M o M o ~ o N o M ^ ~ O ~ O _.-.__.>__--_-. ._-~- -- -__ _ -_~__ _. .. ~_____ . s.__. _ __~ >. -_. _ . N T ~ ~ O 3 O~ ~ O - ~ ~ Ln O~ r Op O O O 00 O O O d' ~ ~ ~~ r- M r r ~ ~' ' ~ 0 0 0 0 0 0 0 gyp . M O In N ~ ~ 0 o ~ N ~ ~ ~ 0 0 0 0 0 0 0 ~ O~ N N M' d' M N d' 9 L ..~ .Q O ~ N .~Q .d ~ ~ ~ 7 ~ V O N (C N 0 0 v, 0 ri m a F~ ® o C~ v; m~ O N Q% 0 ~ N c ~ I .L. ~ ~~ .a~` ~ i ~~ ~ a ~~ a~ City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 3-Existing Wastewater Treatment Facilities the off-gas < 11.82 percent) have not been met on occasion. Instances in which these requirements have not been met generally coincide with either monitoring equipment malfunctions or sludge processing (pumping or dewatering) equipment problems. Limit Pollutant (Ib/hr) Additional Limits Particulate Matter (PM) __ 0.75 _ ._75 Ib/ton dry sludge Inputl 0 Opaclt~r _ ~ NA _,_ ___,_ , 10 percent _ Sulfur Dioxides (SOX) _ 0.21 _ NA Nitrogen Dioxides (N02) ~ 30 40 NA Total HydrocarbonsN_ __- A_ __r____ _yNAe__y_y____ 100 ppmv2mR Carbon Monoxide ~CO)s„ _-__r_ i ~~__~__.__.,Ni4 ~.__~ ~~~ .~~ ~-.__ _~ -__100 ppmv - Lead (Pb) 0 0003 ~ : _ NA _ ~, i Beryllium (Be) 0 00001 ~ NA ; __ Mercury ~H9) _.._._ ~ -- _. 0..002 - ~ _ NA 1 So facility can use the number in 40 CFR 60.155(a)(1)(i). 2 Monthly average concentration for total hydrocarbons in exit gas, corrected to 0 percent moisture and to 7 percent oxygen. Table 3.05-6 Incinerator Emission Limits 3.06 RESIDUALS MANAGEMENT In the current sludge management program, the sludge is incinerated on-site. The ash from the incinerator is then pumped to the ash disposal beds to dry and eventually be landfilled. Decant from the ash beds is recycled to the head of the plant. Table 3.06-1 summarizes the quantities of primary and secondary biosolids that were sent to the centrifuges in fiscal year 2002 through June 2007. Typically, the feed flow consisted of about 30 percent primary biosolids and 70 percent WAS. The average percent solids fed to the centrifuges was about 3.1 and the resulting cake averaged about 27.4 percent solids. The average percent solids recovered was about 97 percent. Polymer was used at an average rate of about 11 Ibs/ton biosolids. PRS WAS Total Cake ~ Cake Year (dry tons/month) (dry tons/month) (dry tons/month) (dry tons/month) (wet tons/month) 2002 ~ 185 ~ _ _ 122 307 ~ ~ _ _ 298 _ _ 980 _ 2003 188 ~ 157 345 _ ~ 335 . 1184 2004 ~ 156 _ 121 277 - 269 ~ 884 v 2005 _ j _ _ r ~ 154 ~ 158 ~. ..._..._._ .. 312 r~_._ ___ _z_~. 303 _ ..___ 1043 __Ar_,__ 7 ___ ___ _.__ ___ __ ~_.__.__... _-_- .____~.~__ _.~_ .--~-- __~.._ ~ __,__ .. ______ _ _v.,_m_~~ ~ _~_m________ ______.-..- 200 159 183 342 331 [ 1148 *through June Table 3.06-1 Dubuque WPCP Annual Sludge Quantities (2002-2007) Prepared by STRAND ASSOCIATES, INC ® 3-14 RAW:ebt\S:\@SAI\151-200\154\002\WrdlReport\S3.doc\052708 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 3-Existing Wastewater Treatment Facilities Raw blended sludge is monitored for heavy metals bimonthly. The sludge is currently analyzed for arsenic, beryllium, cadmium, chromium, lead, nickel, and mercury. The average concentrations for the blended sludge for 2002 and 2005 to present are "less than detection levels" for arsenic, beryllium, and cadmium; 33 mg/kg chromium; 78 mg/kg lead; 23 mg/kg nickel; and 1.1 mg/kg mercury. The federal 40 CFR 503 sludge quality limits for land application do not currently apply because the sludge is incinerated. However, if the sludge processing and disposal methods change in the future, these limits may apply. 3.07 INDUSTRIAL PRETREATMENT PROGRAM Since the average daily design flow for the Dubuque WPCP exceeds 5 mgd, the facility is required to have an industrial pretreatment program developed in accordance with the rules promulgated in 40 CFR 403 and Chapter 62 of the Iowa Administrative Code. The City of Dubuque currently has industrial pretreatment permits with 17 local industries, and one additional permit is likely to be added with a recently announced new processing plant for Hormel Foods. The list of existing industrial pretreatment permits is included below: AY MacDonald MFG Dubuque Stamping Handex of Iowa Mid-America Energy Inland Protein Rousselot Swiss Valley Farms Newt Marine Dubuque Area Sanitary Landfill Artco Fleeting Thermo-Fisher Eagle Window and Door Flexsteel Metal Division Interstate Power Key City Plating Klauer Mfg. Western Dubuque Biodiesel The majority of these industries discharge relatively minor amounts of wastewater flow and loading to the WPCP. Three of the industries (Inland Protein, Rousselot, and Swiss Valley Farms) comprised approximately 38 percent of the WPCP influent BOD loading over the last few years. Prepared by STRAND ASSOCIATES, INC ® 3-15 RAW:ebt1S:\@SAI1151-200\154\002\WrdlReportlS3.doc\052708 SECTION 4 FLOW AND WASTELOAD FORECASTS City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 4-Flow and Wasteload Forecasts This section develops wastewater flow and loading projections for evaluating future treatment facility capacity and needs. Data from current conditions have been used together with population forecasts and development trends to project design flows and loads for the Dubuque WPCP through the year 2030. 4.01 SEWER SERVICE AREA The current sewer service area for the Dubuque WPCP was presented earlier in Figure 1.02-2 of this report. It is anticipated that the overall area served by the Dubuque WPCP will remain as identified, but there may be boundary changes that could modify the overall boundaries of the sewer service area depending on how development occurs in the area tributary to the Dubuque WPCP. 4.02 POPULATION AND GROWTH PROJECTIONS Population projections for the Dubuque WPCP are presented in Figure 4.02-1. These projections were provided to the City by the East Central Intergovernmental -1 Association (ECIA). The projections used the cohort analysis method, which considers birth, death, and i migration rates. This is consistent with the City's long-term planning efforts. The population of the City of Dubuque has been fairly stable for several decades. However, the City has recently experienced significant investment attention and is anticipating significant growth through the year 2030. The census population for the City was approximately 57,700 in the year 2000, and the year 2030 population is projected to be nearly 75,000, which is nearly 1 percent annual growth and nearly 30 percent over the 30-year period from 2000 through 2030. In addition, the City is actively encouraging industrial growth in its planning documents. Nearly 500 acres of industrial development are planned in addition to the existing industries already in the City. 4.03 PROJECTED FLOWS ~ _'i Projecting future wastewater flow requires identification of residential/commercial and industrial wastewater flow, base flows, peaking factors, and anticipated residential/commercial and industrial growth in areas tributary to the Dubuque WPCP. The data used in these evaluations includes daily flow j ,~ measurements from the plant's two magnetic influent flow meters from January 2002 through September 2007. 1 Prepared by STRAND ASSOCIATES, INC ® 4-1 RAW:ebt1S:\@SAI\151--200\154\002\W rdlReportlS4.doc\052708 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 4-Flow and Wasteload Forecasts A. Dry Weather Base Flows and Per Capita Flows Since January 2002, the annual average daily flow treated at the Dubuque WPCP has ranged from a low of approximately 7.3 mgd in 2003 and 2005 to a high of 8.1 mgd in 2007. Over that same time period, the maximum month flow was 10.64 mgd in April 2007, the maximum week flow was 14.65 mgd in June of 2002, the maximum day flow was 27.1 mgd in June 2002, and the maximum hourly flow recorded was nearly 34 mgd in July 2007. To project future design average and maximum flows, an evaluation was made to establish average dry weather flows to the WPCP and then generate an estimate of I/I levels to establish future maximum design flows. The average dry weather flow, which includes background dry weather infiltration, was established from a review of the WWTP influent flows. Daily flows were reviewed for the years 2002 through 2007, and the minimum daily flows to the plant that were less than the minimum monthly flow for the period reviewed, which included 158 days, were used in the analyses. The annual average dry weather flow over this time period was 6.363 mgd, with a range of 6.301 mgd to 6.426 mgd. This flow rate is assumed to contain a minimum amount of I/I expected from the City's collection system. To determine per capita dry weather flow (sometimes referred to as base flow), the average industrial and hauled-waste flows components were subtracted from the dry weather flow, and this was divided by the contributing population. The per capita flow was calculated in this manner for each year and averaged to determine the per capita flow for the period 2002 to 2007. The average dry weather per capital/flow was calculated to be approximately 97 gcd. This per capita flow value was then used to estimate future dry weather base flows from the projected number of residential and commercial customers. Industrial flows were estimated separately, and I/I components to estimate wet weather flows were also considered separately as noted below. B. Design Flow Projections-Wet Weather Design Flows The daily flow data from January 2002 through September 2007 was used to develop wet weather design flows. For each year of data evaluated, the design wet weather flows were calculated. Then, the dry weather base flow and average industrial flow for each year were subtracted from each of the calculated wet weather flows to estimate wet weather I/I volumes. Estimates of the industrial flows for users in the City of Dubuque were made based on flow records from the three major wet industries plus an estimate of total flow for the remaining smaller industries. Table 4.03-1 presents a summary of the various flow determinations for the years 2002 through 2007, including estimates of I/I for each flow category. To develop year 2030 design flows, the dry weather per capita flow of 97 gcd was multiplied to calculate the future dry weather residential/commercial base flow of approximately 7.2 mgd. The amount of I/I in the collection system for each of the design wet weather flows (maximum month, maximum weekly, etc.) was assumed to increase by 10 percent to the year 2030. Wastewater flows from the existing industries were also assumed to increase by 10 percent, and new planned industry was assigned a flow of 1,500 gpd/acre. A factor of 10 percent of the total projected industrial flow was Prepared by STRAND ASSOCIATES, INC.® 4-2 RAW:ebt\S:\@SAI1151-200\154\002\WrdlReportlS4.doc1052708 City of Dubuque, Iowa Dubuque WPCP Facilities Plan Section 4-Flow and Wasteload Forecasts TABLE 4.03-1 EXISTING PER CAPITA FLOWS AND INFILTRATION/INFLOW CALCULATIONS Parameter 2002 2003 2004 2005 2006 2007 Average Population I 57199 57751 57726 57723 57696 57757 Average Dry Weather Flows ~ Total Dry Weather Flow (mgd) 6.301 6.369 6.342 6.378 6.426 6.305 6.354 Average Industrial Flow (mgd) 0.732 0.691 0.688 0.829 0.843 0.923 0.784 Average Hauled Waste Flow (mgd) 0.004 0.004 0.004 0.004 0.004 0.004 0.004 Total Flow without Industrial/Hauled Waste Flows 5.565 5.674 5.650 5.545 5.579 5.378 5.565 Per Capita Dry Weather Flows (gcd) 97 98 98 96 97 93 97 ', Average Annual Flows Total Average Annual Flow (mgd) 7.727 7.377 7.798 7.310 8.001 8.060 7.712 Average Industrial Flow (mgd) 0.732 0.691 0.688 0.829 0.843 0.923 0.784 Average Hauled Waste Flow (mgd) 0.004 0.004 0.004 0.004 0.004 0.004 0.004 Total Flow without Industrial/Hauled Waste Flows 6.991 6.683 7.106 6.477 7.155 7.134 6.924 Per Capita Average Annual Flows (gcd) 122 116 123 112 124 124 120 Average Annual I/I (mgd) 1.426 1.008 1.456 0.932 1.575 1.755 1.359 'I Average Wet Weather Flows Total Wet Weather Flow (mgd) 9.798 9.416 11.198 8.128 10.407 10.640 10.292 Average Industrial Flow (mgd) 0.732 0.691 0.688 0.829 0.843 0.923 0.784 ~, Average Hauled Waste Flow (mgd) 0.004 0.004 0.004 0.004 0.004 0.004 0.004 ' Total Flow without Industrial/Hauled Waste Flows 9.062 8.722 10.506 7.295 9.560 9.713 9.143 Per Capita Wet Weather Flows (gcd) 158 151 182 126 166 168 159 Average Wet Weather I/I (mgd) 3.497 3.047 4.856 1.750 3.981 4.335 3.578 Max. Month Flows* Maximum Month Flow (mgd) 9.570 9.149 10.359 8.126 10.113 10.635 9.965 Industrial Flow (mgd) 0.732 0.691 0.688 0.829 0.843 0.923 0.775 Hauled Waste Flow (mgd) 0.00375 0.00375 0.00375 0.00375 0.00375 0.00375 0.004 Total Flow without Industrial/Hauled Waste Flows 8.835 8.454 9.667 7.293 9.267 9.709 9.186 Per Capita Maximum Month Flows (gcd) 154 146 167 126 161 168 159 Maximum Month I/I (mgd) 3.269 2.780 4.017 1.748 3.687 4.330 3.617 Max. Week Flows' Maximum Week Flow (mgd) 14.654 10.718 12.692 8.779 11.468 13.866 12.680 Industrial Flow (mgd) 0.732 0.691 0.688 0.829 0.843 0.923 0.775 Hauled Waste Flow (mgd) 0.00375 0.00375 0.00375 0.00375 0.00375 0.00375 0.004 ' Total Flow without Industrial/Hauled Waste Flows 13.919 10.024 12.000 7.946 10.621 12.940 11.901 Per Capita Maximum Week Flows (gcd) 243 174 208 138 184 224 207 Maximum Month I/I (mgd) 8.353 4.349 6.350 2.401 5.042 7.561 6.331 Max. Day Flows'`* ~ Maximum Day Flow (mgd) 27.053 20.256 17.629 10.254 16.760 18.884 22.064 Industrial Flow (mgd) 0.732 0.691 0.688 0.829 0.843 0.923 0.782 Hauled Waste Flow (mgd) 0.00375 0.00375 0.00375 0.00375 0.00375 0.00375 0.004 ~ Total Flow without Industrial/Hauled Waste Flows 26.317 19.561 16.937 9.421 15.913 17.957 21.279 Per Capita Maximum Day Flows (gcd) 460 339 293 163 276 311 370 Maximum Day I/I (mgd) 20.752 13.887 11.287 3.876 10.334 12.579 15.739 " 2005 data were omitted from the average calculations (far right column). ** 2004, 2005 and 2006 data were omitted from the average calculations (far right column). Prepared by Strand Associates, Inc.® Page 1 of 1 TMS:pII\S:\@SAI\1 51-20 011 54\002\WrdlReport\Table 4.03-1.doc\052708 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 4-Flow and Wasteload Forecasts added to account for unforeseen industrial growth. This factor is commonly in the range of 0 to 25 percent. Minor hauled waste flows of approximately 8,000 gpd were also included in the projections. The projected year 2030 design flows are presented in Table 4.03-2. The average dry weather base flow is projected to increase by 40 percent from approximately 6.5 mgd to 9.1 mgd as the result of 30 percent more people and an approximate doubling of industrial discharges. The average annual design flow and average wet weather flows are expected to increase by 30 to 35 percent to 10.64 mgd and 13.46 mgd, respectively. Peak flows (maximum week, maximum day, and maximum hourly) are expected to increase by lower percentages since the I/I component was assumed to increase by only 10 percent. The assumption of a 10 percent increase in I/I is based on the following: The City is currently conducting a comprehensive collection system study to identify problem areas for I/I reduction. While it is likely that some I/I can be removed, at this time the amount is undefined. In addition, the City's goal will be to eliminate sanitary sewer overflows, which will result in more flow being discharged to the plant when such overfows are eliminated. Therefore, an I/I increase of 10 percent was included as a compromise between the I/I reduction anticipated (but undefined) and the potential increase in flows resulting from sewer overflow elimination. A summary of the year 2030 design flows is presented below. Average Dry Weather 9.14 mgd Annual Average 10.64 mgd Average Wet Weather 13.47 mgd Maximum Monthly 13.13 mgd Maximum Weekly 15.83 mgd Maximum Daily 24.50 mgd Maximum Hourly 40.86 mgd 4.04 PROJECTED LOADINGS The per capita and future design BODS and TSS loadings for the City of Dubuque were developed using an analysis similar to that employed for the flow projections. The first step is to determine per capita loadings for BODS and TSS and then develop future projections using the per capita loadings plus separate industrial loading estimates. A. Per Capita Loadings The per capita WPCP loading estimates for BODS and TSS are based on data collected from 2002 to 2007. Estimates of the per capita loadings are presented in Table 4.04-1 and Table 4.04-2 for BODS and TSS, respectively. The average per capita BODS load (no industrial or hauled wastes) was calculated as 0.18 Ibs per capita per day (pcd), which is within the typical range of 0.17 to 0.22 pcd. However, the average per capita TSS load of 0.17 pcd is lower than the normal range for TSS of 0.20 to 0.25 pcd. Previously in Section 3 of this facilities plan, the influent loadings were discussed with respect to the Prepared by STRAND ASSOCIATES, INC ® 4-3 RAW:ebt\S:\@SAI\151-200\154\0021Wrd1ReportlS4.doc\052708 City of Dubuque, Iowa Dubuque WPCP Facilities Plan Section 4-Flow and Wasteload Forecasts TABLE 4.03-2 DESIGN FLOW PROJECTIONS __ _ _ - ~_ __ Current 2030 Population _ Projected Populafion _ ~ 57,757 74,663 __ ~a ResidentiaUCommercial Dry Weather Base Flows6(includes dry weath er I/I) Per capita flow (gPptl ) __97_ --~--__~oA~ --Y--- ,----_--97 ___ . ~__a_~.~~~v~_~.__.____._. ~.» . ,Average Dry~Weather Res. Flow (mgd) _ 5 577 7 209 --.. ~ _.- ~ -- _----__ Infiltration/Inflow __ ___Y........-__.._._~.~.~._ _.e_.~~_v«.~ . _.,,. _._..M_~ _. .____._«-~ -~ - - r _ ~ ~, - - __ Avg Day_(mgd) _ P_ ~ . 1 359 _~._~. ~ 1 495 Wet Weather Avg Day (mgd)- 3 935_ 4 329 - Maxlmum Month (mgd) 3 621 _ e _M 3 983rr -_~__ 4 Maxlmum Week (mgd) 6 075 ~ 6 683 _ s- _ _ .... _,., - _~_ Maximum Day (mgd)___ N. _ _ ~ a e ~ ~_ ~ _ _ 14 628 _ _. _ 15 359 . a___ e - _ _~e . _ Peak Hourly (mgd) _ _ . 22 605 .___ e 23 735 ~_~ ~. Hauled-in Waste Existing Hauled in_Waste (mgd~m__~ ___~_~ ~_ i ~ __ _____ 0 004 ~ 0 004 :_._ - Western Dubuque_Biodiesel_______ - _ __, ___~ ~_~ __ __-a~___0 000 ~ 0 004 _.. __ ~ - Total Hauled in Waste mgd) __ 0 004 ~ 0 008 Industrial Waste _.- .__ _ ___ ~ _ _ , __,._ Existing Mayor Industrial Flow~top 3) (mgd) ~ _ . _0 723. ._ W _ _ _0 795 ___ . Existing Minor Industrial Flow (other 13) _P~ 4--- -- -- ~ (mgd) - _.. _.. _.~.___~~.W n_~.~.___~-_~~ ~._~ -_~-__~~. ~-- -- ar :___-~~ -- __ ~...~a~.0.200 .~~u_ m ._.°_0.220 Future Planned Industrial Flow (mgd) 0 000 ~ 0 737 _~~_ ~ Future Unforeseen Industrial Flow (mgd) 0 000 ( -._ 0 175 - ~~ ~ ~ _0 923, Total Industrial Flow (mgd) _ _ _ 1 927 ~- _ ___ ~~Design Flow Summary. _ . ___ _ _ .u. _ _ __ Average Dry Weather Flow ~ 6 503 ~ _ _ 9 144 ,_, r ~ _._ Average Annual Flow (mgd) 7 862 10 639 .. -- ~ Average Wet Weather Flow (mgd 10 439 - 13 473 - - _ Maximum Month Flow (mgd)~not running avg) 10 124 ~ 13 127 12 579 Maximum Week Flow (mgd)_ ___ _ _ - .a_ _ 15 827 --- - - -- ~-_ _ _ - _ _Y_„ __,_~21 131__~ Maxlmum Day Flow (mgd) __ LL___ _ R __y24 503 ____ ~_ __LL . ...._-_._ - > > -- ~_ _ _ _ ~ __ _ _ __ , _ _ Maximum Hourly Flow (mgd) _ __ _ ______~_ ___35 839 ~ - _ 40 863_ Prepared by Strand Associates, Inc.° Page 1 of 1 TMS:pII\S:\@SAI\151-200\154\002\WrdlReport\Table 4.03-2.doc\052208 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 4-Flow and Wasteload Forecasts potential that the influent TSS loadings (and BODS loadings) may be underestimated. In that analysis, justification was presented that indicated the actual influent TSS loads may be 40 percent higher than the data suggests. If this is accurate, the influent BODS load would also be impacted, resulting in an approximate 25 to 30 percent increase in influent BODS loadings. ~~ 2002 _. ~ 2003 ~ ~ 2004 ~n _ __ 2005 _~ 2006 2007 Average Populatlon __ _ ___ __ ___ ~___r _ ( 57,199 .. __wefi57,751 _ 57,726 ___57,723 57,696_ ___57,757 Y _ ,,- Total BOD (Ibs) 1.8,327 17,057 ~ 15,377 ~ 16,3__ 59 17,988 16,846 16,993_= Industrial BOD ~ 6,217 6,218 5,211 ~ 6,881 7,059 7,625 6,535 Hauled Waste 188 188 188 ( 188 j vw __~ .~~_.v_ ~~.m_~_.~ ~.,_ _-_ _ - - --- . _._ _ Residential/Commercial/Public _ _11,923, _____10,651 _„___9,979 y,_9,290 ~._. _ . - ~ __~. ~ a Per Capita. ~Ib/cap/day) 0 208 0184 _ 0173 ~-~0 161 ~ Table 4.04-1 Per Capita BOD Loading Calculations 188 ~~ ,10,741_ r. ~_ 0.186 188 _x _ .9,033 0 156 _ µzx_y , 188 -- _______10,270_ .._ __ , 0 178 2002 2003 ~ 2004 2005 2006 2007 Average 5 ~~_ ~ Populatlon 57,199 57,751 57,726 723 57, 57 696 57 ~ ,757 _ ~ . Total TSS (Ibs)_, _y ,_„___„ U_ __, _ 1.1_,993 ~n=10,867_ ._ ,10,766 ~ _,_11,420 ,11,637,__ __._11,821__ _~__ 11,417 Industrial T_SS (top 3).__n:.m_ 1,528 1,501 1_,216 1,494_ 1_,856__ ( 2,075 1_,612__: Hauled Waste 469 469 8 469 ~ 469 ( 469 ~ 469 469 _Residential/Commercial/Public _ 9,996_, _._„_8,89 _ 9,081_. _____ 9,457 ] ,_9,311 _ ~~m9,278 m_ ___,_9,337 _ .~ __. r ~~_-_ ~ Per Capita (Ib/cap/day) __ v n_ _ 0175 __ .._ _.~_a 0 154 __ _ 0.157 ~ _ 0.164. - 0.161 ~ __ 0.161 _m~_ n.__ 0 162 Table 4.04-2 Per Capita TSS Loading Calculations For planning purposes, the higher per capita loadings were assumed to better represent current and future loadings. The calculated per capita BODS loading of 0.178 pcd was increased by approximately 25 percent to 0.223 pcd, and the calculated per capita TSS loading of 0.162 pcd was increased by 40 percent to 0.227 pcd. Both of these per capita values are within the range commonly used for planning. In addition the new per capita loadings better match the anticipated loadings from new residential development, which usually includes garbage grinders resulting in higher per capita loadings. Prepared by STRAND ASSOCIATES, INC ° 4-4 RAW:ebt\S:\@SAI\151-200\154\002\W rdlReporNS4.doc\052708 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 4-Flow and Wasteload Forecasts For the purposes of developing design loadings, the following per capita loadings are used in these analyses: BODS 0.223 pcd (see discussion above) TSS 0.227 pcd (see discussion above) NH3-N 0.024 pcd (based on typical reference loadings) TKN 0.036 pcd (based on typical reference loadings) P 0.006 pcd (based on typical reference loadings) B. Projected Design Loadings The projected average design loadings for BODS and TSS were developed using the per capita loadings calculated above for the residential/commercial portion of the projections and then adding the existing industrial loadings, the planned future industrial loadings, an allowance (5 percent of the total) for unforeseen industrial loadings, and the anticipated hauled waste loadings to develop future total design loadings. Most of the loading components are relatively straightforward to develop. However, the planned industrial loadings are based on the following assumptions: 1. The City has 491 acres of new industrial development planned. 2. As noted previously, a typical wastewater flow value of 1,500 gpd/acre for the future planned industrial flows was assumed. 3. The future planned industrial BODS loading increases were assumed to be in proportion to the anticipated increase in industrial flows. This results in a similar mix of wet and dry industries in the future, with a subsequent similar overall industrial waste composition. 4. Future industrial TSS loadings will be equal to the future industrial BOD loadings. This is different than the current industrial loading characteristics. However, it is likely to have similar BOD and TSS loadings rather than highly soluble industrial loadings. Tables 4.04-3 and 4.04-4 summarize the design BODS and TSS loads, respectively, for the year 2030. The maximum design loadings were developed based on analyses of the variability of influent BODS and TSS loadings at the WPCP from 2002 through 2007. Annual average-based peaking factors were developed for the maximum month, maximum week, and maximum day loading conditions for each year. These peaking factors were then applied to the year 2030 average loading projections to develop the maximum design loadings in the future. The year 2030 design loadings for the Dubuque WPCP are listed below: Average BODS 36,900 Ibs/day Max. Month BODS 41,200 Ibs/day Average TSS 29,400 Ibs/day Max. Month TSS 37,100 Ibd/day Prepared by STRAND ASSOCIATES, INC.° 4-5 RAW:ebt\S:\@SAI1151-200\154\0021W rdlReport\S4.doc1052708 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 4-Flow and Wasteload Forecasts ,~._._u._ ~.~._-~-- _---~_.~es z-~xF__r___r_~_r_______m~.~a__.ma~ _w_~___ ,___~.__.__ Current _-~~_~ 2030 __ _ __._~~~.~ ___ __ Projected Population _ ,~_,ad____ ~ _ .~_~ ~. Per Capita BOD, Ib/cap/day _ Restdential ~Ib/d~ _ _T 57,757 __~ . _._._ 0 223 12,866 74,663 , _. m. 0.223_ 16,632 _ ~__. »_-- - ~-s Existing. Hauled Wastes m,4~~ _ _ a _ _ e Ty __ Western Dubuque Biodiesel _ _ __ _, _ __ .....Y. _a_. Future Hauled Wastes - ~ ~_ ____ _ __ _ 188 - Y - _.~ 188 1,650 - .n~ _.~.n. _.~ ~ Total Hauled Wastes (Ib/d~ ~__ f - 188 ~ _ _ 1,838_y Existing Ma/or Industries (top 3) _rF,_ P~_,~y:£ss_ _ __ ~_, __ 7,625__1 8_,388 Existing Minor Industries bother 13) - - -~ Future Planned Industries (49.1 acres planned~~ -- - ~ - 8,296 Future Unforeseen Industrial -- - 1,758 --~ Total Industrial BOD (Ib/dj ~ _ 7,625 18,441 _~ . s _ ~_ ~_rt.____~ .__ --~- --- _ __~ ~~.~-___..~..___,_ . ,__ Des~n BOD Summary ___ _. ~..N.,~._ _.__ ___ Current ,_ _~~.__ ~~_~ _~. 2030 Total Average BOD _, - -~~~----- ~ - ---__ ~~.__~.__._w_. 20,700 .._.~M____._ 36 900_,ry .__~_~ Total Maximum Month BOD 23,100 41,200 { Total Maximum Week BOD -~ x ~ _ 3 27,500 __ ~ ~ 49,000 ~., _ ~_. -- - Total Maximum Day BOD _ ~ 43,600 77,700 Table 4.04-3 Design BODS Loading Projections _ _ _ ~ _- Current ~ 2030 Protected Population ~ 57,757 ~ _74,663 , Pe r Caplta TSS,_Ib/cap/day .w __ ~ 0 227 ` 0 227 _ Residential _.~_ s - -- Existing Hauled Wastes _ Western Dubuque Blodiesel Future Hauled Wastes T ~ 13,099. 469 w 16,933 469 Total Hauled Wastes ~ I e______r~ _____~__N 469 ~ - ' 469 -T ~ ~z __.~ Existing Mayor Industries (top 3) _______a ua~ __a~ - ~S3 2,075_ __2,282 Existing Minor Industries (other 13) Future Planned Industrles Future Unforeseen Industrial ~a ~ _._~n_ ~x_ .__. __ _ _.._. _._. ~ .._._ .m Total Industrial TSS _ ~ ~ - , .. _,_v.m._ae._P..__n._e .. 2,075 8,296 1,399 ___~6 ._a~ - 11,977 - _~ TSS Desi n_Loadm s - _~ 9 = --- 9 __ . -~ Current ~-- -_ 2030 ~ - -- - Total Average TSS - -- 15,600 ~ -~ 29,400 - Maxlmum Monthly TSS __ _ _µ _____ __ _ _ ___ „_ _, , ___19,700_ __ 37,100 Table 4.04-4 Design TSS Loading Projections Prepared by STRAND ASSOCIATES, INC ° 4-6 RAW:ebt\S:\@SAI\151-200\154\002\Wrd\Report\S4.doc\052708 SECTION 5 EVALUATION OF EXISTING FACILITIES AND SCREENING OF ALTERNATIVES City of Dubuque, Iowa Section 5-Evaluation of Existing Facilities Dubuque Water Pollution Control Plant Facilities Plan and Screening of Alternatives This section of the report examines the ability of the existing WPCP facilities to treat the projected future flows and loadings developed in Section 4 while meeting the anticipated future NPDES permit requirements. This section also evaluates the compliance of the current facilities with the Iowa Wastewater Facilities Design Standards and other applicable design criteria. The review focuses on the rated capacity of the existing facilities, age of the existing facilities, reliability of the existing facilities, and other factors related to operating and maintaining the existing facilities. 5.01 REGULATORY AND NPDES PERMITTING ISSUES Permit limits and regulatory standards are revised as society's understanding of its environmental impact grows. Implementation of new permit limits and regulatory standards can require substantial changes in WWTP operations and treatment facility needs. New regulations affect effluent limits and the disposal of sludge or biosolids, among other things. The purpose of this section is to discuss regulatory initiatives now under consideration, review their impact on the Dubuque WPCP, and recommend provisions that should be included in any proposed WPCP modifications to address these future regulatory concerns. A. National Nutrient Strateav In December 2000, EPA published recommended regional water quality criteria with the goal of reducing the impact of excess nutrient discharges to the nation's waterbodies. The parameters represent both causal criteria [total phosphorus (TP) and total nitrogen (TN)] as well as physical/biological responses (chlorophyll a and turbidity). The goal was for the EPA to work with the states to adopt the recommended criteria or to develop more regionally specific water quality criteria for nutrients. States were expected to adopt or revise water quality standards by 2004, but this schedule was revised to allow states another two to three years to develop rules. As of this writing, most states, including Iowa, are still in the data collection phase and have not developed new water quality standards for all regulated parameters. The Dubuque WPCP discharges to the Mississippi River located in Ecoregion VII as defined by the EPA. The EPA's baseline water quality criteria for rivers in this ecoregion are presented in Table 5.01-1. Note that a criterion is the allowable _ Parameter Nutrient Criteria concentration of a substance in the _~ .. waterbody. Permit limits will typically be Total Phosphorus 33.00 µg/L xTr ~~ -------- ---~- ~ --- - --~ ------_~t _~mm-~__.~r~_ _~__ .......__. higher than a criterion because consideration Total Nitrogen 0 54 mg/L can be given to dilution of the efFluent with Chlorophyll a 1 50 µg/L the receiving water body. In the case where ~.,_.__ __ n--~ __~~ _ _ -~~ __._. Turbldlty ~1 70 NTU the receiving water body's background water - --- -- -- --- -- --- quality is higher than the criterion, the permit Table 5.01-1 EPA Recommended Nutrient limit may be set at the criterion. Criteria for Rivers in Ecoregion VII Prepared by STRAND ASSOCIATES, INC ® 5-1 RAW:ebt1S:1@SAI\151-200\154\0021Wrd\Report\S5.doc\052708 City of Dubuque, Iowa Section 5-Evaluation of Existing Facilities Dubuque Water Pollution Control Plant Facilities Plan and Screening of Alternatives B. Iowa Nutrient Strategies and Status The DNR was contacted to determine its approximate schedule for nutrient criteria development. The DNR is currently developing a state comprehensive nutrient management strategy, which includes the following preliminary steps: 1. Development of a comprehensive state nutrient budget for the maximum volume, frequency, and concentration of nutrients for each watershed that addresses all significant sources of nutrients in a water of this state on a watershed basis. This step is complete and a copy of the nutrient budget report is available on the DNR's Web site. 2. Assessment of the available nutrient control technologies required to identify and assess their effectiveness. 3. Development and adoption of administrative rules required to establish numeric water quality standards for nutrients. According to DNR staff, there is no definitive schedule for implementing nutrient limits in NPDES permits in response to nutrient criteria development. The process of establishing water quality standards and nutrient criteria, as well as assessing nutrient control technologies, is ongoing. After the criteria have been established, it will take another period of years to determine specifically how the criteria might be applied and then to implement limits into NPDES permits. Therefore, while nutrient limits are not likely for the Dubuque WPCP within the next NPDES permit cycle, and potentially not with the next two cycles, it is likely that the Dubuque WPCP will need to meet efFluent phosphorus and/or TN limits within the 20-year planning period. To date in the State of Iowa, nutrient limits have been imposed in NPDES permits as the result of the development of total maximum daily loads (TMDLs) for a receiving stream. In the majority of these cases, the nutrient limit has been assigned a value equal to a treatment plant's current mass loadings to the water body. Justification for this approach is that the DNR's research has shown about 10 percent of the TN and 15 percent of the TP in a typical Iowa stream is discharged from point sources. C. Impaired Waters and Total Maximum Daily Load Impacts The Clean Water Act (CWA) provides special authority for restoring polluted or impaired waters. For waterbodies that appear on the list of impaired waters [303(d) list], the CWA mandated development of the maximum amount of a specific pollutant that a waterbody can receive and still meet water quality standards, referred to as the TMDL. A TMDL also allocates the maximum amount of each identified pollutant of concern that can be contributed from both NPDES permitted discharges and nonpoint (surface runoff sources. Prepared by STRAND ASSOCIATES, INC ° 5-2 RAW:ebt1S:\@SAI\151-200\154\002\Wrd\ReportlS5.doc\052708 City of Dubuque, Iowa Section 5-Evaluation of Existing Facilities Dubuque Water Pollution Control Plant Facilities Plan and Screening of Alternatives Figure 5.01-1 shows the water bodies in northeastern Iowa that are on the 2006 impaired waters list. Only one stretch of the Mississippi River is currently on the list. This stretch includes the area between Lock and Dam No. 11, which is approximately one-half mile upstream of the Dubuque WPCP outfall, and Lock and Dam No. 10 in Guttenburg to the north. This segment of the Mississippi River is included on the impaired waters list because of high levels of aluminum. Additional impacts are included for exotic species and organic enrichment/low dissolved oxygen (DO), both of which are directly related to zebra mussels and are considered minor/nonimpairing by the DNR. Northeast Iowa -Impaired Waters 2006 - ~,~.,,a 1\ i~iY ~~rc.11`IIV ... ~Fw.l f..i,,.v. ..J 7~;~ v.. v:. .....I.n .~~ is r .r,~v ~:. •I..Ili n.v...LJ tll.~-n •n~ .ll~'- y~eml r.f loll l.i...LJ,YtY~lllw, Source: Iowa DNR Web site Figure 5.01-1 Impaired Waters in Northeast Iowa With respect to the aluminum impairment, the following excerpt is cited from the DNR's water quality assessment database based on the 2006 water quality assessment developed for this river segment: "The Class B (WW) (aquatic life) uses were assessed (monitored) as "not supported" due to violations of Iowa's chronic criterion for aluminum in water. Results of water quality monitoring from Illinois EPA station M-13 at Lock and Dam 11 showed that four of 12 samples analyzed for toxic metals during the 2001-2003 period exceeded Iowa's Class B(WW) chronic criterion for aluminum of 388 µg/L. According to U.S. EPA guidelines for Section 305(b) water quality assessments (U.S. EPA 1997b, page 3-18), more than one violation of a water quality criterion for a toxic pollutant in an abundant data set (at least 10 samples over a 3-year period) indicates an impairment of aquatic life uses." NJ. Prepared by STRAND ASSOCIATES, INC.° 5-3 RAW:ebt\S:\@SAI\151--200\154\002\W rd\Report\S5. doc\052708 City of Dubuque, Iowa Section 5-Evaluation of Existing Facilities Dubuque Water Pollution Control Plant Facilities Plan and Screening of Alternatives Based on comments from the DNR, the only potential 303(d) listing for the Mississippi River near the Dubuque WPCP outfall in the next impairment list update (scheduled to be released in May or June 2008) would be for mercury levels in fish. Some mercury samples in largemouth bass in 2006 were a little higher than the DNR's trigger level for mercury of 0.3 ppm. DNR Fisheries conducted follow-up monitoring in the fall of 2007, and if the mercury levels in the follow-up samples are above 0.3 ppm, the DNR will issue a fish consumption advisory for that segment of river. The fish consumption uses would be considered impaired and that segment of the Mississippi River would be added to Iowa's 2008 list of impaired waters [303(d) list]. D. AntidearadationRnalysis Within the EPA's framework of water quality criteria, the nation's waterbodies are to be protected through compliance with water quality standards. All water quality standards are comprised of the following: 1. Designated uses. 2. Instream water quality criteria (both numeric and narrative) required to support the designated use. 3. An antidegradation policy intended to prevent waterbodies that do meet water quality criteria from deteriorating beyond their current condition. For the 20-year design period considered in this report, the average annual design flow of 10.64 mgd is less than the previously established design dry weather average flow of 13.39 mgd. Therefore, an antidegradation analysis should not be required. E. Anticipated NPDES Permit Requirements The current NPDES permit was developed in 1998 with an expiration date of 2003. While the City has applied for permit reissuance as required, the plant has been operating on that expired permit for the past four years. The DNR was requested to develop anticipated NPDES permit limits for the next permit reissuance, which is expected in 2008. In response to this request, the DNR issued a memorandum titled WLA/Permit Limits for the City of Dubuque Water Pollution Control Plant dated October 18, 2007, and also provided information on wasteload allocations/NPDES permit limits for toxics, TDS, chlorides, and iron in a spreadsheet. The memorandum and spreadsheet output are included in Appendix B. The NPDES effluent limits for CBODS and TSS are not expected to change. In addition, the DNR does not anticipate new limits for ammonia, TN, or phosphorus. However, a few of the existing permit limits will probably be modified (Table 5.01-2): Prepared by STRAND ASSOCIATES, INC ® 5-4 RAW:ebt\S:\@SAI\151-200\154\002\WrdlReportlS5.doc\052708 City of Dubuque, Iowa Section 5-Evaluation of Existing Facilities Dubuque Water Pollution Control Plant Facilities Plan and Screening of Alternatives 1. The existing fecal coliform limit of 200 colony forming units (CFU)/100 milliliter (mL) (daily maximum) is expected to be replaced with both daily maximum and monthly geometric mean E. coli limits. 2. The existing effluent pH range of 6.0 to 9.0 standard units is expected to be modified to a range of 6.5 to 9.0 standard units. 3. Anew DO limit of 5.0 mg/L is anticipated; currently there is no effluent DO limit. ~ Average Average Daily Daily Monthly Weekly Mirnmum Maximum CBODS 1 25 mg/L 40 mg/L - --- w_w_ Suspended Sollds ~ 30 mg/L . ~~ _ 45 mg/L Chlorine Residuals 151 µg/L ~ __ rv N,vT_ ,,, 202 µg/L E Colig 126/100 mLb ~ 235/100 mL ^ pH (standard units) ~ 6 5 s u. 9 0 s u _ Dissolved Oxygen e _ ,__~ __~ _ Y_~. _- ~a 1 ~ _ 1 -- - - -- 5.0 mg/L _ e .m~_._ e Disinfection required from March 15 through November 15. n Geometric mean. Table 5.01-2 Anticipated NPDES Permit Limits F. Future Nutrient Limits Nutrient limits for TN and P are not anticipated in the next permit cycle. However, based on information from the DNR, experience in other areas of the country, and the significant effort being made in the State of Iowa to develop water quality standards for nutrients and other parameters, it is likely that within the 20-year planning period of this facilities plan, effluent nutrient limits will be imposed in the plant's NPDES permit. The major nutrient concern for discharges to the Mississippi River basin is hypoxia in the Gulf of Mexico related to nitrogen loadings from the Mississippi River. Hypoxic zones are low in DO and are incapable of supporting desirable natural marine life. Fish and other mobile aquatic species are forced to migrate from hypoxic areas, and less mobile species may experience considerable die-off. Hypoxia results from an overload of organic matter, exacerbated by a high input of nutrients. The end result of the excess nutrients is an accelerated production of organic matter (algae blooms, higher organisms feeding on algae) that increases the abundance of suspended organic matter that sinks to the saltier depth, decomposes, and exhausts the remaining available oxygen, thus creating a hypoxic zone. For the purpose of this facilities planning, we have assumed that future total nitrogen and total phosphorus limits will be implemented in the Dubuque WPCP NPDES permit within the 20-year planning period. Based on total nitrogen limits required in other areas of the country, an effluent limit of 5 mg/L or less could be implemented. In addition, an effluent phosphorus limit in the range of 0.5 mg/L or less is also likely. Because of the uncertainties surrounding the timing of future Prepared by STRAND ASSOCIATES, INC.° 5-5 RAW:ebt\S:\@SAI\151-200\154\002\W rd\Report\S5.doc1052708 City of Dubuque, Iowa Section rEvaluation of Existing Facilities Dubuque Water Pollution Control Plant Facilities Plan and Screening of Alternatives nutrient limits, as well as the magnitude of any future limits, this facilities plan will not include a detailed evaluation of the treatment processes and facilities needed to meet such future limits. However, for all process alternatives evaluated, the impacts required to construct future nutrient removal facilities and operations will be carefully considered. G. Biosolids Disposal and Beneficial Reuse Incinerator ash from the Dubuque WPCP is currently dewatered and held at the WPCP site for a period of one to several years. Final disposal in the past has been by landfilling. However, more recent disposal has been through beneficial reuse of the ash as a component in engineered fill. If incineration is eliminated, solids produced at the WPCP will require disposal to the land either by land application on agricultural lands or through the production of compost for distribution to other users. These disposal alternatives are regulated by Iowa Administrative Code (IAC) 567, Chapter 67, which includes permissible metals concentrations in both Class I (exceptional quality) or Class II (normal quality) biosolids. The sludge produced from current Dubuque WPCP operations appears to meet the metals concentration limits included in IAC 567, Chapter 67 for arsenic, cadmium, lead, nickel, and mercury. Year 2007 monitoring data indicates that the current sludge concentrations for these five metals were all significantly lower than required for land application. No monitoring is currently conducted for copper, selenium, or zinc, which are also regulated by IAC 567, Chapter 67. Therefore, these parameters will need to be monitored to determine whether exceptional quality biosolids can be produced from the existing sludge. For the purposes of this planning document, we have assumed that the copper, selenium, and zinc concentrations in the sludge meet the requirements of IAC 567, Chapter 67. H. Sludae Incineration Regulations In January 2007 the USEPA announced that municipal sludge incineration operations would be regulated under Section 112 of the Clean Air Act. However, the results of a recent court case may reverse that decision and may result in regulation under Section 129 in lieu of Section 112. Section 129 covers municipal solid waste incinerators and is expected to require significantly more monitoring for specific compounds than the current permit requires, including particulate matter, sulfur dioxide, nitrogen oxides, cadmium, mercury, lead, dioxins, and furans. The Dubuque sludge incinerators would likely meet new numerical limits imposed by Section 129. However, the annual monitoring costs and reporting effort could increase substantially. I. Chemical Security Wastewater treatment plants are exempt from federal chemical security regulations developed for the chemical industry. Draft legislation would establish permanent security requirements for chemical plants, which may be defined to include water and wastewater utilities. Currently water and wastewater utilities provide security measures and programs on a voluntary basis. If the legislation is passed and requires wastewater utilities to comply, the Dubuque WPCP chlorine and bisulfite facilities would likely be regulated and may require additional controls, monitoring, and security measures. Prepared by STRAND ASSOCIATES, INC ® 5-6 RAW:ebt1S:\@SAI\151-200\154\002\W rd\ReportlS5.doc\052708 City of Dubuque, Iowa Section 5-Evaluation of Existing Facilities Dubuque Water Pollution Control Plant Facilities Plan and Screening of Alternatives 5.02 UNIT PROCESS EVALUATION This section evaluates the ability of the existing WPCP facilities to treat the projected future flows and loadings while meeting the anticipated future NPDES permit requirements. In addition, other nontreatment issues are discussed. Where applicable, treatment alternatives are identified for detailed evaluation and consideration in Section 6 of this report. The City of Dubuque has an existing WWTP constituting a significant investment from the City's residences, industries, commercial enterprises, and other entities. A wastewater treatment facility has been in operation at the current WPCP site since the late 1960s. As a result, there is a substantial investment in the infrastructure both of the conveyance and treatment facilities. Given this investment, the overall community acceptance of the current location of the Dubuque WPCP, and the availability of adequate land at or near the current site both for current facility needs and future expansion, all alternatives evaluated in this report will use the existing site and continue the discharge of treated effluent to the Mississippi River. A. Influent Screenina Influent wastewater enters the plant through two force mains (FM), the 18-inch Catfish FM and the 42-inch Cedar-Terminal FM, and is metered by two magnetic flow meters installed in a meter vault. The preliminary treatment facilities consist of two mechanically cleaned bar screens and avortex-type grit removal system. The mechanical screens are climber-type screens with 3/4-inch bar openings. The screenings are dropped into a screw conveyor/wash press and are discharged to a dumpster for landfilling. The bypass channel has a manually cleaned bar screen with 1 5/8-inch bar openings. The existing mechanical screens were installed in 1993, and the nominal capacity of each screen is 20 mgd for a total capacity of 40 mgd. The screens are nearing the end of their useful life, and while they have required relatively minor maintenance since being installed, the 3/4-inch openings allow a significant amount of relatively large solids to pass to the downstream treatment units. Most screening installations in the last 5 to 10 years have included screens with 1/8-inch to 1/4-inch openings to reduce the amount of debris and material passing to downstream treatment processes. Therefore, we recommend that finer influent wastewater screening be implemented at the Dubuque WPCP. While it may be feasible to install screens with 1/8-inch openings, the additional head loss could create high headwaters at the treatment plant. Based on a preliminary hydraulic analysis, at this time we recommend a screen opening of 1/4-inch for screens installed in the existing channels. Based on this, the following influent screening alternatives will be evaluated in Section 6: ^ S1: Renovate the existing screening frames with 3/8-inch screens and climber rake; install screenings washer/compactor. ^ S2: Replace existing screens with new 1/4-inch fine screens and washer/compactor. Prepared by STRAND ASSOCIATES, INC.° 5-7 RAW:ebt\S:\@SAI\1 51-20 011 54\002\WrdlReportlS5.doc\052708 City of Dubuque, Iowa Section 5-Evaluation of Existing Facilities Dubuque Water Pollution Control Plant Facilities Plan and Screening of Alternatives B. Grit Removal Following screening, wastewater flows to the vortex grit units, which were installed in 1993. The two units each have a nominal capacity of approximately 34 mgd. This type of grit removal still represents the state-of--the art for wastewater treatment, and since these facilities have adequate capacity for the future design flows, the existing grit removal structures should remain. Grit settles to the bottom of the basins and is pumped to two grit classifiers by recessed impeller vortex grit pumps. These pumps were replaced in 2007. Grit is dewatered in the classifiers, and this material is discharged to a recently replaced belt conveyor that discharges dewatered grit to a dumpster for landfilling. The grit classifiers are corroded and in need of replacement. The plant also has problems with the grit pump suction and discharge lines plugging. Costs for replacement of the grit classifiers are included in the opinion of cost for the project. The classifiers will be rearranged to minimize the length of auxiliary conveyors needed to convey grit to the dumpster. New conveyors will be of the screw conveyor type rather than belted conveyors. In addition, an allowance for replacing and/or reconfiguring the grit suction and discharge piping will be included in the opinion of costs. C. Primary Sedimentation Wastewater flows by gravity from the grit chambers to three 90-foot-diameter primary clarifiers. The tanks have lightweight concrete dome covers that were installed in the 1970s and resurfaced in the 1980s. The clarifier drives and mechanisms were installed in the 1980s and are planned to be refurbished as part of the plant's preventive maintenance program. New baffles and weirs were installed during the 1993 project. Primary sludge is pumped to two primary sludge holding tanks using air diaphragm pumps that were installed in 1993. Scum and grease are pumped to a separate holding and decanting tank by progressive cavity pumps that were installed in the 1970s. The scum box on each clarifier is constantly flowing with flush water, so the amount of scum and grease requiring pumping is considerably more than necessary. The 90-foot-diameter sedimentation tanks have a total surface area of 19,100 square feet, which provides a surface overflow rate (SOR) of 705 gpd/ft2 at the design average wet weather (AWW) flow rate of 13.47 mgd and an SOR of 2,143 gpd/ft2 at the design peak hourly flow rate of 40.9 mgd. The Iowa Facilities Design Standards includes a maximum AWW SOR of 1,000 gpd/ft2 (condition met) and a maximum peak hourly SOR of 1,500 gpd/ft2 (condition not met). However, these design standards do allow a higher peak hourly SOR as long as the primary BOD removal efficiency is decreased for design of the downstream secondary treatment facilities. If a fourth 90-foot-diameter primary clarifier were constructed, the peak hourly design SOR would be approximately 1,600 gpd/ft2, which is still higher than the recommended design standard of 1,500 gpd/ft2. However, a fourth clarifier would provide improved redundancy for preventive maintenance and would be expected to improve primary treatment performance, especially at higher wet weather flows. The following primary treatment modifications are included in the opinion of capital cost developed in Section 6 of this report: Prepared by STRAND ASSOCIATES, INC ° 5-8 RAW:ebt1S:\@SAI\151-200\154\002\WrdlReportlS5.doc\052708 City of Dubuque, Iowa Section 5-Evaluation of Existing Facilities Dubuque Water Pollution Control Plant Facilities Plan and Screening of Alternatives 1. A fourth 90-foot-diameter clarifier is planned to be constructed to provide more reliable primary treatment and improve wet weather treatment capacity. However, it is noted that this unit is not required by code and could be constructed in the future. 2. The existing domes will be removed and replaced with flat fiberglass weir covers only. The ventilation system will be modified and directed to an odor control system discussed later in this section. 3. The primary scum pumps will be replaced with new progressing cavity pumps. 4. The flush water system used. to remove scum will be modified to reduce the volume of water utilized. 5. The central building will be modified to accommodate removal of the domes. 6. The primary influent splitter structure will be upgraded with new gates. D. Biological Treatment The biological treatment facilities include the activated sludge basins, aeration mixers, and the oxygen delivery system. There are three trains of aeration basins, each with a volume of approximately 630,000 gallons for a total volume of 1.89-million gallons. The plant has only utilized two of the three trains (1.26-million gallons) for the past 10 to 15 years. Each train is separated into three passes, and each pass has three stages in series. Each stage has a surface aerator for a total of 9 aerators per train and 27 aerators total. The HPO activated sludge facilities were installed in the 1970s. Most of the mixers are original and are operating beyond the expected life of such equipment. The original cryogenic oxygen generation system was decommissioned in the early 1990s, and the plant has purchased liquid oxygen since then. The existing facilities continue to serve the plant well, even with only two of the three trains operating. Future design BOD loadings to secondary treatment are approximately 30,900 Ibs/day (maximum month), which equates to a volumetric BOD load of 122 Ibs/1,000 ft3/day if all three basins are in service. At an mixed liquor volatile suspended solids (MLVSS) of 3,500 mg/L, the maximum month food-to-microorganism (F:M) ratio is approximately 0.56 Ibs BODS/Ib MLVSS/day. The oxygen demand is projected to be approximately 15 to 17 tons/day at the future design average BOD loadings assuming 90 percent oxygen utilization and 1.1 Ibs 02/Ib BODS according to Iowa Design Standards. Nitrification requirements were not considered in this calculation as ammonia limits are not anticipated and the plant doesn't typically nitrify now because of suppressed pH levels. However, if future TN limits are imposed, an additional oxygen demand will need to be met for biological nitrification reactions. This will be considered in the alternative evaluations in Section 6. All these design values are within the normal range of high-rate HPO activated sludge facility design standards. Therefore, the HPO activated sludge basins appear to have adequate volume, and physical expansion would not be required to accommodate the future design loadings. However, the system would require replacement of the existing 34-year-old surface mixers to improve energy efficiency and Prepared by STRAND ASSOCIATES, INC ® 5-9 RAW:ebt\S:\@SAI\1 51-20 011 54\002\WrdlReportlS5.doc1052708 City of Dubuque, Iowa Section 5-Evaluation of Existing Facilities Dubuque Water Pollution Control Plant Facilities Plan and Screening of Alternatives mechanical reliability. The existing controls would also be upgraded to improve efficiencies. Therefore, while the existing HPO activated sludge facilities are a viable option for the future secondary treatment needs, the costs to upgrade the existing HPO activated sludge facilities will be significant and it makes sense to evaluate other options at this time. In addition, the potential for future nutrient limits will require careful consideration as HPO activated sludge treatment is typically not as amenable as air activated sludge for removal of TN and TP. This report evaluates the following alternatives in Section 6: ^ B1 HPO activated sludge; new aerators and controls; hauled liquid 02. ^ B2 HPO activated sludge; new aerators and controls; on-site 02 generation. ^ B3 Air activated sludge; expand tankage; new blowers and diffusers. ^ B4 Moving bed biological reactor (MBBR) activated sludge; expand tankage; new blowers and diffusers. Each of these alternatives includes the following with respect to the existing facilities: 1. Reuse of the existing activated sludge basins to the extent practical. A structural analyses of the tanks and concrete decks will be required during final design. 2. Reuse of the existing four final clarifiers (see below). 3. Reuse of the existing RAS pumps (six pumps at 3,000 gpm each), which were installed in the mid-1990s. 4. Reuse of the two existing WAS pumps. Process sizing for the biological treatment alternatives will be based on the design loads and flows summarized in Section 4, assuming 30 percent removal of the plant influent BODS loading in the primary clarifiers. Other biological treatment alternatives were also considered, such as wetland treatment or wetland polishing, aquatic plant systems (hyacinths, duckweed), and similar "natural" treatment systems. In general, these systems have been used for relatively small wastewater treatment applications to polish treated effluent and/or remove nutrients from secondary effluent prior to discharge. This size limitation is the result of the significant land area required for such systems. Most recent applications of natural treatment systems have been for flows of less than 100,000 gpd and typically less than 25,000 gpd. There have been some systems operating at higher flow rates, but these systems have extensive land areas dedicated for treatment. The design average effluent flow from the Dubuque WPCP is approximately 10 mgd. Using a constructed wetland system or similar aquatic plant polishing system to remove nutrients from the existing treated effluent from the Dubuque WPCP would require a land area of approximately 120 acres and perhaps significantly more. By comparison, the existing WPCP site is only about 20 acres in total area. Sizing a wetland or similar system to provide full treatment of raw wastewater for the City of Dubuque would require considerably more land, perhaps an additional 500 to 1,000 acres. For these Prepared by STRAND ASSOCIATES, INC ® 5-10 RAW:ebt\S:1@SAIN 51-200\154\002\Wrd\Report\S5.doc\052708 City of Dubuque, Iowa Section 5-Evaluation of Existing Facilities Dubuque Water Pollution Control Plant Facilities Plan and Screening of Alternatives reasons, wetland treatment and similar aquatic plant treatment systems are not considered in this report. E. Final Clarification The existing facility has four final clarifiers, each with a diameter of 105 feet. This provides a total surface area of 34,600 square feet. At a peak hourly surface overflow rate of 1,200 gpd/ft2, the rated capacity of the final clarifiers is 41.5 mgd. Based on a peak hourly solids loading rate of 50 pounds per day per square foot, a mixed liquor suspended solids (MESS) concentration of 4,000 mg/L, and an RAS rate of 30 percent of the forward flow, the peak hourly capacity is approximately 39.9 mgd. Therefore, based only on surface overflow rate (SOR) and solids loading rate, the final clarification capacity appears to be adequate for the design flows. If HPO activated sludge is not used in the future, higher RAS rates may be required, and the solids loading rate on the final clarifiers could exceed design recommendations. However, it is likely the MESS would be lower with air activated sludge alternatives. While the surface area appears to be adequate, the plant has had some problems with high effluent solids during high-flow events. This is likely the result of deep sludge blankets (normally 3 to 6 feet) maintained in the shallow clarifiers [12 feet side water depth (SWD)], which does not provide adequate buffer to high peak flows and leads to solids washout. The reason for the deep blankets is as follows. The incinerators require a dewatered solids concentration of approximately 26 to 28 percent to operate efficiently (low auxiliary fuel oil addition). To achieve cake solids in this range, the primary sludge fraction of total plant sludge needs to be above approximately 55 percent (Figure 5.02-1 ). Since the raw wastewater loadings to the plant are fairly soluble, however, the amount of WAS produced is relatively high, and to achieve the target primary sludge-to-WAS ratio requires storing WAS. Over time, the WAS storage capacity is exhausted and WAS begins to build up in the final clarifiers. 35 , -- ^ ^ I- 30 ' • ~~ i ^ ~ ~ ~ ^ f/1 25 1 ~ ~ ~ ~ - ~ ~ ~ C ~ 20 - C1 Y ~C 15 V - 10 -------- ---- ------- ---....----- ---- 30% 35% 40% 45% 50% 55% 60% 65% 70% 75% 80% Percent Primary Sludge in Total Feed Sludge Figure 5.02-1 Effect of Sludge Blend on Cake Dryness Prepared by STRAND ASSOCIATES, INC.° 5-11 RAW:ebt\S:\@SAI\151--200\154\0021Wrd\Report\SS.doc\052708 City of Dubuque, Iowa Section 5-Evaluation of Existing Facilities Dubuque Water Pollution Control Plant Facilities Plan and Screening of Alternatives The issue of high WAS levels compared to primary sludge quantities will be addressed in the following manner: 1. If the existing incineration system is maintained, aerobic digestion or other WAS minimization process will be required to reduce the amount of WAS. Alternatively, longer sludge ages could be employed in the activated sludge system [current solids retention time (SRT) is approximately five days with an observed yield of approximately 0.55 Ibs WAS/Ib BODS]. However, based on past plant experience, longer sludge ages result in proliferation of filamentous organisms. Therefore, for the purpose of this report, we have assumed that aerobic WAS digestion would be employed if sludge incineration is continued. 2. If alternative sludge management systems are employed, the significance of the primary sludge-to-WAS mass ratio is reduced, and a dedicated WAS reduction process is not required. Density current baffles were installed in the 1990s and have improved the performance of the final clarifiers. Over the last few years, there have been some additional developments in energy dissipation inlets in the clarification industry. Because of the concerns with peak flows and the impacts on solids washout, new energy dissipation inlets have been included for all four clarifiers. F. Effluent Disinfection The existing disinfection system at the Dubuque WPCP employs a chlorine gas solution added in a mixing chamber downstream of the final clarifiers and upstream of the chlorine contact tanks. Dechlorination is provided by addition of liquid magnesium bisulfite solution in a mixing chamber immediately downstream of the chlorine contact tank. Effluent from the dechlorination chamber discharges to an outfall pipe to the Mississippi River. The two chlorine contact tanks each have a volume of 24,150 ft3 for a total volume of 48,300 ft3. At the average wet weather flow of 13.5 mgd, this provides about 38 minutes of detention time, and at the peak hourly flow of 40.9 mgd, about 13 minutes of detention time is provided. The current facility meets the Iowa Wastewater Facilities Design Standards-Chapter 20 Disinfection requirement of 30 minutes detention time at average wet weather flow but does not meet the requirement for 15 minutes detention time at the peak hourly wet weather flow. The current fecal coliform limit has been exceeded on some occasions with the current system. The existing system has been in compliance with the average residual chlorine limit on a regular basis, but it has exceeded the maximum day residual chlorine limit several times since 2003. The disinfection system will have to meet the new water quality standards for E. coli as discussed previously in this section as well as in Section 6. Redundant gaseous chlorination equipment was originally installed, but only one chlorinator and related equipment is currently operational. If gaseous chlorination is continued, replacement of all the equipment will be required. In addition, because of concerns with a gaseous chlorine release in the area, a new scrubber for the storage and handling rooms would be necessary. Prepared by STRAND ASSOCIATES, INC ® 5-12 RAW:ebt\S:\@SAI\151-200\154\002\Wrd\ReportlS5.doc\052708 City of Dubuque, Iowa Section 5-Evaluation of Existing Facilities Dubuque Water Pollution Control Plant Facilities Plan and Screening of Alternatives The Dubuque WPCP operating staff has expressed a desire to replace the chlorine gas system with a system with less potential emergency risk and exposure concerns. Systems identified for evaluation include the following (see Section 6): ^ D1 Replace existing gas chlorination equipment and continue with gaseous chlorine and liquid dechlorination; install chlorine gas scrubber. ^ D2 Convert to liquid sodium hypochlorite system and continue with liquid dechlorination. ^ D3 Convert to on-site hypochlorite generation and continue with liquid dechlorination. ^ D4 Convert to ozone disinfection. ^ D5 Convert to ultraviolet light (UV) disinfection. G. Peak Flow Management/Eaualization Peak hourly design flows are not anticipated to exceed the WPCP final clarifier capacity as noted previously in this section. However, because of the high effluent suspended solids discharged in the past during peak flow events, and relatively shallow depth of the final clarifiers, this report considers alternatives to reduce peak flows through the final clarifiers and improve peak flow management overall. In other states, flow blending facilities are allowed and provide the means to off-load the secondary treatment facilities while still meeting effluent discharge limits. However, based on discussions with the DNR, flow blending in Iowa may not be allowed. Early in 2007, the City conducted a preliminary evaluation of the existing trickling filters, which have not been used for about 20 years, for reuse as peak flow equalization basins. These structures are each 195 feet in diameter with a potential liquid depth of about 7 feet, for a total volume of approximately 3.1-million gallons. Hydraulically, peak flows could be diverted to these structures downstream of primary clarification using existing flow control structures, as this was the normal forward flow since the late 1960s when these structures were built. Modifications would be required to allow forward flows to continue to the secondary treatment processes while diverting excess flows above an established threshold (e.g., 15 or 20 mgd). The overflow from the equalization structures would be set at an elevation of approximately 1 foot below the top of the existing walls. This overflow would not receive any flow until the tanks were full. If the tanks would completely fill because of a long sustained peak flow event, the plant could either shut off flow to the equalization tanks to direct all flow to secondary treatment, or the tanks could be designed to overflow to the secondary treatment basins. Based on preliminary hydraulic evaluations and a review of tank elevations in comparison to upstream and downstream treatment units, it appears these existing tanks are well positioned for such operation. While an exhaustive peak flow evaluation was not completed for this planning report, we did review several major recent events, including two significant peak flow events in July of 2007. Figures 5.02-2 and 5.02-3 graphically represents the potential equalization provided by these structures under two peak flow events that occurred in July 2007. For the first event, which is a fairly typical occurrence in Dubuque, flows increased from about 6 mgd to approximately 27 mgd within a few hours and then slowly decreased back to 10 mgd over several more hours. This event (Figure 5.02-2) would only have required 300,000 gallons of equalization to maintain maximum flows through the secondary treatment system at 15 mgd. The volume of these structures would have been adequate to maintain even lower maximum flows if desired. Prepared by STRAND ASSOCIATES, INC ® 5-13 RAW:ebt1S:\@SAI\151-200\154\002\W rdlReportlS5.doc\052708 City of Dubuque, Iowa Section 5-Evaluation of Existing Facilities Dubuque Water Pollution Control Plant Facilities Plan and Screening of Alternatives 30 T- ----- -- - ---- ---- -- 25 +~ ~ 20 Required Storage ~ Flows> 15 mgd stored - 300,000 gal - 15 -_~_ _~ - _ _ -_.T~ - ---- --. . c ~ 10 c 5 - ~ N fV _„~ Y).,, ~ r M., ~ 0. N ~„ r N a O r. ~~ r M~ O ~ N W. ~~~~ , ~ ~ ~ - M IN ~.~ ~., ~~N,,,~.,~ 0 r M R7 O N ~~.~.~ M M. ~, 0~, W. Y7... O r O O O r N N N N N N N N N N N N N N M M M O O O O r r r r N N N M M M M N N N N Time of Day Figure 5.02-2 Potential Equalization of July 3 and 4, 2007, Rain Event 40 ----------- .___ __ ------__«~_ ----~ __-_-_-_-- 35 a~ 30 E 3 25 Flows> 22 mgd stored __ _ Required Storage - 3,100,000 gal -._. -- ~~. _ ~ G 20 .~_ ~ . - - - _ __ -- - _- m 15 c 10 5 h r '~ 00 r 117 00 N ~ et N O u7 M r O ~ O N <O Of N ~O O M ~O O M r~ O ~ ~ N r t!y M N O '~ M r O d' N r .. .. .. . . .. . . .. .. . .. .. .. .. O O r N N M O r r N N N N N r N M M d' lfJ <O (O N 00 W Q1 O r r r T- r Time of Day Figure 5.02-3 Potential Equalization of July 17 and 18, 2007, Rain Event For the second event later in July, influent flows increased from about 6 mgd to nearly 35 mgd over a couple of hours and sustained flows above 30 mgd for nearly 10 hours. The two trickling filter structures, if used for equalization, could have reduced the peak flow through the secondary treatment system to approximately 22 mgd. Therefore, the use of these structures should provide a relatively low-cost improvement to peak flow management, and we recommend these modifications be included in the project. Prepared by STRAND ASSOCIATES, INC.° 5-14 RAW: ebt\S:\@SAI\151--200\154\002\W rd\Report\SS.doc\052708 City of Dubuque, Iowa Section 5-Evaluation of Existing Facilities Dubuque Water Pollution Control Plant Facilities Plan and Screening of Alternatives The following trickling filter structure modifications are included in the recommended improvements for peak flow equalization: 1. The existing trickling filter structures will be converted to equalization tanks. 2. Primary clarifier effluent will flow by gravity to these structures. 3. The existing rock media, distributors, and underdrain will be removed. 4. The wall connection to the base slab requires evaluation following rock and underdrain removal to determine whether this joint is watertight. If not, the joint will need to be sealed. 5. Draining of the stored wastewater will be provided with new pumps in the existing intermediate pumping station. 6. Tank washdown facilities will be required at a minimum to clean the basins after a peak flow event. In addition to flow equalization, the activated sludge facilities will be designed to enable operation in the contact stabilization mode during (Figure 5.02-4) sustained peak flow events rather than the current plug flow mode. Switching to contact stabilization during peak flows would reduce the solids loading on the final clarifiers while storing solids in the converted reaeration (reoxygenation) basins. This has been shown to improve peak flow treatment for activated sludge facilities and is expected to reduce effluent suspended solids loadings to the Mississippi River during peak flow events. This modification will require some additional flow control structures and/or modification of existing structures. RAS PIUg FIOW Wastewater z Mode (Normal) Effluent to Mixed Liquor Final Disinfection Clarifier Aeration Basins RAS RAS Reaeration Contact and Storage Stabilization (15' and 2"d Pass) Mode Effluent to (Peak Flows) Wastewater Directed Mixed Liquor Final Disinfection © to Last Pass Clarifier Contact Basin (3rd Pass) Figure 5.02-4 Contact Stabilization Conversion for Peak Flows Prepared by STRAND ASSOCIATES, INC.® 5-15 RAW:ebt\S:\@SAI\151--200\154\002\Wrd\ReportlSS.doc\052708 City of Dubuque, Iowa Section 5-Evaluation of Existing Facilities Dubuque Water Pollution Control Plant Facilities Plan and Screening of Alternatives H. Effluent Dissolved Oxygen and pH Limits When the plant's NPDES permit is reissued, it will likely include new effluent DO limits as well as a revised effluent pH limit. The DO limit is expected to be 5.0 mg/L, and the effluent pH range will likely be 6.5 to 9.0 standard units (changed from 6.0 to 9.0 standard units). The HPO activated sludge system typically operates at higher DO levels than conventional air activated sludge systems (Figure 5.02-5). The range in the HPO basins is from near zero to approximately 20 mg/L, and seasonally high DOs in response to lower wastewater temperatures during winter operations are apparent. Based on the current operations, consistently meeting an effluent DO limit of 5.0 mg/L would be difficult without additional controls and potentially additional structures or processes. It is likely that some of the DO is released at the final clarifier weirs, in the chlorine contact tank, and in the dechlorination basin. Therefore, WPCP effluent DO levels will be lower than the DO levels in the HPO basins. The method of meeting the anticipated effluent DO level, however, is dependent on the selection of the biological treatment alternative. If HPO activated sludge is continued, the plant may be able to simply improve DO control to maintain the DO in the HPO basins at a sufficiently high level to meet an effluent DO limit. If air activated sludge is implemented, an effluent cascade or effluent postaeration facility would need to be constructed as the DO level would consistently be less than 5 mg/L. The plant is currently collecting data to compare plant effluent DO with HPO basin DO to determine how much DO is lost through the final clarifiers, chlorine contact tank, and decholorination tank. J rn O O c .y m a 2 20 18 16 14 12 10 8 6 4 2 0 oti ~a~` . - - - - •~ Anticipated Effluent DO Limit = 5 mg/L -. J \. ~ f ~ -. - - - - - - - .. A - L • - • - l t -~ -- _ f -. ..~ i•r~ - _ - - .. .- - - - '~1 ~._ - _. o`pry `pti ~`p~ 4p~ cpP ~~ cAh 4ph cpe `p6 cp1 ~ o° ~ om ~' oe ~' ct/ ~' cP ~° Date Figure 5.02-5 HPO Basin DO Levels (2002 through 2007) The effluent pH is measured upstream of the chlorine contact tank. The normal pH at this point in the process is between approximately 6.2 and 6.7 standard units with some excursions outside of that Prepared by STRAND ASSOCIATES, INC.° 5-16 RAW:ebt\S:\@SAI\151--200\154\002\W rdlReport\SS.doc\052708 City of Dubuque, Iowa Section 5-Evaluation of Existing Facilities Dubuque Water Pollution Control Plant Facilities Plan and Screening of Alternatives range (Figure 5.02-6). The low pH levels are the result of operating ahigh-rate HPO system with covered basins. Carbon dioxide released from the biological oxidation reactions builds up in the basin headspace, resulting in carbonic acid generation in the MLSS, which lowers the pH. This C02 can be released to some degree through mixing and turbulence. Limited testing by the plant has indicated that the pH increases through the chlorine contact tank and the dechlorination tank by about 0.2 to 0.3 standard units. If additional mixing and/or turbulence were implemented, the WPCP effluent would increase and the anticipated minimum pH limit of 6.5 standard units would likely be met more frequently. Other alternatives to meet the limit include cascade or postaeration to strip C02 from the wastewater. In addition, the final basin in the HPO activated sludge system could be uncovered to release C02 from this last stage prior to the final clarifiers. The method of meeting the anticipated effluent pH limit, however, is dependent on the selection of the biological treatment alternative and is discussed in Section 6. Residuals Management Residuals management includes all the operations associated with primary sludge and WAS storage, thickening, processing, stabilization, and disposal. The present method of residuals management uses centrifuges to dewater blended primary sludge and WAS followed by fluidized bed incineration of the residuals. Ash is discharged to two ash lagoons and stored on-site. The existing incinerators were installed nearly 40 years ago, and major upgrades were implemented in the 1993 project. The capacity of the incinerators is adequate for the future design solids loadings from the plant. However, the incinerator units and appurtenant equipment have operated beyond the normal useful life, and required several major repairs; the maintenance requirements for these units continue to increase. Since major rehabilitation of the existing incineration facilities is again required to continue use of these facilities, it is appropriate to consider other alternatives at this time. Prepared by STRAND ASSOCIATES, INC ® 5-17 RAW:ebt1S:\@SAI\151-200\154\002\W rd\Report\S5.doc\052708 City of Dubuque, Iowa Section 5-Evaluation of Existing Facilities Dubuque Water Pollution Control Plant Facilities Plan and Screening of Alternatives e.o 7.5 I 7.0 I i 6.5 2 ' Q .~ iv 6.0 ~ ~ Anticipated Effluent Low pH Ltmit = 6.5 W 5.5 ,, i 5.0 1 4.5 4.0 )armory )°\Ary O°~pry )~`o~ O°4p~ )~c~ O°~pb )JC y O°4py )°c~ O°Gpb )vc ~ Date Figure 5.02-6 Effluent pH Levels (2002 through 2007) The alternatives to be included in Section 6 for residuals management are as follows: ^ RM1a Major rehabilitation of the two existing incinerators. ^ RM1 b Major rehabilitation of one incinerator; no rehabilitation of the second unit. ^ RM2a Major rehabilitation of one incinerator with lime stabilization for backup. ^ RM2b One new incinerator with lime stabilization for backup. ^ RM3 Lime stabilization with agricultural land application. ^ RM4 Anaerobic digestion with agricultural land application. ^ RM5 Anaerobic digestion with composting. ^ RM6 Anaerobic digestion with drying and agricultural land application. ^ RM7 Drying with agricultural land application. The comparison among the alternatives will include the continued use of centrifuges to dewater either raw sludge (Alternatives RM1, RM2, RM3, and RM7) or stabilized biosolids (RM4, RM5, and RM6) with improved standby capacity and reliability. The plant currently has two centrifuges that were installed in the early 1990s as well as a belt filter press located in an adjacent room that was installed in 1983. The proposed project will include two new centrifuges and reuse of one of the existing centrifuges. The second existing centrifuge will be used for parts, and the existing belt filter press will be removed. Additionally, several "sludge minimization" systems and technologies are being promoted in the wastewater industry. These systems claim to significantly reduce the amount of secondary sludge (WAS) requiring disposal. For example, the Cannibal® system utilizes a controlled sidestream Prepared by STRAND ASSOCIATES, INC ® 5-18 RAW:ebt\S:\@SAI\151-200\754\002\WrdlReportlS5.doc\052708 City of Dubuque, Iowa Section rEvaluation of Existing Facilities Dubuque Water Pollution Control Plant Facilities Plan and Screening of Alternatives bioreactor and other equipment to significantly reduce the amount of WAS generated. However, the Cannibal® system is typically used at conventional air activated sludge plants that employ longer sludge ages in the 10 to 15 day (or longer) range. For that reason, the Cannibal® system is not evaluated in this report. Another method of sludge minimization is ozonation of the return activated sludge, which has been demonstrated at one plant in Italy to reduce WAS generation by as much as 80 percent (no effect on primary sludge). A 2004 Water Environment Research Foundation (WERE) report on sludge minimization technologies indicated that although the ozone system technology could successfully reduce secondary sludge generation by as much as 80 percent, these systems were generally not cost-effective and resulted in higher overall operating costs as well as high initial capital costs. More recently, a company is promoting an ozone system for sludge minimization that is claimed to be significantly more cost-effective. The status of sludge minimization technologies and application in the United States for systems similar to the Dubuque WPCP is not established. While such systems may have merit, for the purposes of this facilities planning report, more proven systems provide significantly more confidence that the selected approach will be viable for the long-term operation of the plant. However, WAS minimization technologies will be considered in Section 6 as an add-on technology to the selected approach. Regardless of which residuals management alternative is selected, minimizing WAS generation could have a beneficial effect and could reduce costs. J. Sampling The influent (and possibly effluent) samplers are suspected of collecting unrepresentative samples of the raw wastewater solids and BOD concentrations as noted in Section 4. The system includes the use of two small centrifugal pumps that pump wastewater from each influent force main to a dedicated automated sampler. Plant effluent is pumped across the site to the headworks building where it is sampled in a third automated sampler. This report includes new automated samplers for both of the influent force mains and the plant efFluent. The location of the influent samplers will depend on the selection of a disinfection alternative. Should the gaseous chlorination system be replaced with an alternative system, the new influent samplers will be located in the space currently occupied by the chlorination equipment. If gaseous chlorination is continued, a new dedicated sampler building will be provided for the influent samplers. The efFluent sampler will be located in a dedicated sampler building located near the efFluent from the plant rather than sampling effluent pumped across the site. K. Emergency Power Dual power feeds are available to provide emergency power and are sufficient to run all necessary process equipment. Because of the concerns regarding system vulnerability, the City of Dubuque is also considering the installation of an independent emergency generator or multiple generators at the WPCP. Costs for this emergency power system will be reviewed in Section 6 and included in the overall ', recommended plan. However, this element may be eliminated or postponed. Prepared by STRAND ASSOCIATES, INC ® 5-19 RAW:ebt\S:\@SAI\151-200\154\0021Wrd1ReportlS5.doc1052708 City of Dubuque, Iowa Section 5-Evaluation of Existing Facilities Dubuque Water Pollution Control Plant Facilities Plan and Screening of Alternatives L. Administration Building, Laboratory, and Locker Rooms The administration building houses staff offices, the laboratory, locker rooms, storage areas, meeting rooms, and related spaces. In general, only minor upgrades have been implemented for these facilities since the 1970s, and the existing space is in need of significant refurbishment and potential expansion. In particular, the laboratory facilities, which provide analytical services for the WPCP, the water utility, and several other customers, do not have adequate space or separation for water and wastewater analytical requirements. In addition, the needs of the industrial pretreatment monitoring program should be addressed with a remodeling and expansion of the laboratory facilities. The recommendations and opinion of costs include allowances to refurbish the existing spaces, including improving energy efficiency, and an expansion of the laboratory facilities. A detailed space needs study is needed and will be provided during the design phase of the project. M. Vehicle Storage and Maintenance Building Vehicular storage and maintenance facilities are limited at the site, and several large pieces of equipment are typically stored outside or in buildings not designed for vehicular storage. A new vehicular storage and maintenance garage is included in the project budget. A detailed evaluation of space needs will be included during the design phase of the project. N. Sewer Cleaning Debris Pad Currently, sewer cleaning crews use the WPCP site to store sewer cleaning/jetting debris. To improve dewatering and handling of such material, a drained concrete pad is included in the project budget. The location of this pad is dependent on the sludge management alternative selection. O. Odor Control The City is sensitive to potential odors generated at the WPCP. In the 1970s and 1980s, the WPCP was the source of significant odors associated with the Zimpro sludge conditioning system. In the 1990s, Zimpro was decommissioned and odors are currently not a major issue at the site. The main source of odors appears to be the primary clarifiers and preliminary treatment building, although odor complaints are rare. The new facilities will be designed to add odor control equipment in the future if such facilities are required. However, odors are not anticipated to be significantly different from the current facilities. P. Flood Protection A WWTP has been operating on the existing site since the 1960s. The current treatment facility, as constructed, satisfies code requirements for flood protection. All existing units are above the 100-year flood elevation for the Mississippi River of 611.30 feet above mean sea level. All current facilities on the site are protected to a minimum elevation of approximately 625 feet. Prepared by STRAND ASSOCIATES, INC.® 5-20 RAW:ebt\S:\@SAI\151-200\154\002\W rdlReport\S5.doc\052708 SECTION 6 WASTEWATER TREATMENT ALTERNATIVES EVALUATIONS City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section C~Wastewater Treatment Alternatives Evaluations This Section of the report presents the analyses of alternatives identified in Section 5 as well as the other recommended project elements discussed in Section 5. 6.01 INTRODUCTION The design flows and loadings that provide the basis for the alternative analysis presented in this Section were developed in Section 4. Section 5 described the deficiencies of the existing WPCP to meet the future design conditions and anticipated NPDES permit limits and identified treatment alternatives recommended for evaluation. This section evaluates the treatment alternatives identified in Section 5 on the bases of capital costs, annual O&M costs, 20-year present worth costs, nonmonetary issues, and environmental issues. These alternative technology evaluations include the following: 1. Influent Screening 2. Biological Treatment 3. EfFluent Disinfection 4. Residuals Management In addition to these alternative analyses, this Section also reviews other recommended improvements at the Dubuque WPCP. These project elements are developed and described based on the technology selections of the four major alternative analyses presented above. These additional project elements include: 1. Grit Removal 2. Primary Treatment 3. Final Clarification 4. EfFluent DO and pH Control 5. Peak Flow Management 6. Sampling 7. Emergency Backup Power and Electrical Service 8. Administration Building, Laboratory, and Locker Rooms 9. Vehicle Storage and Maintenance Building 10. Sewer Cleaning Debris Pad 11. Odor Control 12. Other Equipment Replacement 13. Miscellaneous Piping, Valves, and Mechanical Components The process of developing cost opinions and comparing alternatives on a present worth basis is presented in Appendix C. 6.02 INFLUENT SCREENING ALTERNATIVES ANALYSIS The existing 3/4-inch climber screens have provided relatively low maintenance operation for nearly 15 years. At the time these were installed, this type of screen was the state-of--the-art for influent screening. However, within the last 10 years, the trend for influent screening has been to install finer screens for removal of finer solids, as well as screenings washers. Washers are used to remove Prepared by STRAND ASSOCIATES, INC ® 6-1 RAW:ebt\S:\@SAI\151-2001154\0021Wrd\Report\S6.doc\052708 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section frWastewater Treatment Alternatives Evaluations organic material from the screenings for further treatment, which reduces odors in the screening area and results in a product that is more amenable to landfill disposal. Screen openings within the range of 1/4-inch to 1/8-inch and even finer have become common in Europe and the United States. The major advantages of using fine screens compared to coarser screens is reduced plugging in downstream piping and pumps, reduced floating material in downstream tanks, and reduced plastics and other identifiable solids in the sludge or biosolids, which is especially important if the solids are to be land applied or otherwise beneficially reused. For the Dubuque WPCP, two fine screening alternatives were evaluated to replace the existing coarse screening equipment. A. Description of Alternatives Alternative S1 includes installing a finer bar screen and rake on the existing frames. The existing screen frames, controls, and other appurtenances would remain. Based on information from the screen manufacturer, a screening opening of 3/8-inch appears to be the narrowest retrofit opening available and was assumed for this alternative. A new screenings washer/compactor is included for each screen. Alternative S2 includes replacing both of the existing screens with a different style fine screen. This alternative includes costs for two fine screens with 1/4-inch bar spacing, a screw conveyor, a screenings washer, and related equipment and controls. Finer screens should be considered during final design but may result in head losses through the screens that are too great for the existing influent channels. There are a number of screen types that could be used in the existing channels at the Dubuque WPCP, including step screens, basket screens, perforated plate screens, and fine bar screens. Each of these has advantages and disadvantages and should be carefully evaluated in detail during final design. For the purpose of this report, we have included opinions of capital costs for both 1/4-inch step screens (Alternative S2a) and perforated plate screens (Alternative S2b). B. Monetary Comparisons Table 6.02-1 summarizes our opinion of capital costs for the screening alternatives. Annual operation and maintenance (O&M) costs for the alternatives are expected to differ marginally in that the finer screens will remove more material and result in higher landfilling costs for screenings disposal. However, because the finer screens included in Alternatives 2a and 2b remove more material, these screens have the potential to decrease ongoing maintenance costs related to plugging and abrasion of downstream equipment, processes, and piping. For this reason, O&M costs were not included in this monetary evaluation. In addition, future equipment replacement and salvage costs of the equipment were assumed to be zero since this equipment is expected to have a life of approximately 20 years. Alternative S1 has a much lower projected capital cost and present worth cost since only the screening bars, rakes, and screenings washers are being replaced (Table 6.02-1 ). Alternative S2a and Alternative S2b include completely new systems and, therefore, higher initial capital costs. Prepared by STRAND ASSOCIATES, INC.® 6-2 RAW:ebt\S:\@SAI\151-200\154\002\WrdlReport\S6.doc\052708 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 6-Wastewater Treatment Alternatives Evaluations Alt. S1 ~ Alt. S2a Alt. S2b New 1/4-Inch New Bars New 1/4-Inch Perforated Capital Cost Existing Screens Step Screens Plate Screens ~_ - --- - Equipment ~ $305,100 $500,000 $720,000 z Structural ~ $0 _ ~ $10,000 _ $0~ {Mechanical $55,000 ~ $92,000 $130,000 Electncal _~. $61,000 _ __ _.._$102,000 __ _._ _ $144,000_, _ ___~ __ __.~_.__ __ ____~ v._ . ~____n_._ .__m__ ..__._ . ~..~ _ Site Work -.- _ _ _~. $0 . $0 ~_- _.$0 Subtotal $421,100 $704,000 _ __ _ __ 4.. $994,000 _~ ~_ _ W -_ -. -- _ General Conditions 8% ~ $34,000 ---- $56,000 - _ r_~~ ~~ $80,000_ I __..~,. ~- ~ ---T - Subtotal _.__.~r,..~.~ - - --~_~ m ,,. $455,100 _-_ $760,000 ~ $1,074,,000 $266,000 ~ $376,000 Enymeering + Contingencies @ 35% $159,000 _ ~ ~ „Subtotal. Capital Costs _ _:_~ .__w, 61T___ _____ __ ____$614,1.00 ~_: - $_1,026,000 1,450,000 _ _ ~ > > __ l__~ r a ~~~ e__,_______._..~ Table 6.02-1 Influent Screening Opinion of Capital Cost Summary For both alternatives, a significant increase in screenings quantities is expected. For Alternative S1, the screenings quantities are expected to approximately double from the existing installation and for S2, the screenings quantities would likely more than double. Therefore, O&M costs for the screens will likely increase over the existing screens because of additional landfill costs for the increased amount of screenings. C. Nonmonetary Considerations Nonmonetary comparisons normally include factors such as equipment reliability, user flexibility, future expandability, and related issues. In general, these factors are not significantly different between the two alternatives. Both alternatives will provide improved screenings capture compared to the existing coarse screens, and both alternatives will provide reductions in downstream plugging problems and similar problems resulting from rags and other large solids. D. Environmental Considerations Environmental considerations for the two alternatives are also not anticipated to be significantly different. Compared to the existing coarse screens, both of the alternatives will remove more plastics and other materials that would create nuisances with land application of biosolids, should land application be implemented. This is an environmental benefit in that it provides a better product for agricultural reuse that will also be more acceptable to farmers. E. Recommended Screening Alternative Although Alternative S1 has a lower capital cost and marginally lower O&M costs, we recommend implementing Alternative S2 (new 1/4-inch screens). These screens would better protect downstream equipment, would remove more large solids that are not biodegradable, and would match the wastewater treatment industry's trend of installing finer screens. The selection of the type of screen to Prepared by STRAND ASSOCIATES, INC ® 6-3 RAW:ebt1S:\@SAI\151-200\154\0021W rdlReport\S6.doc\052708 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 6-Wastewater Treatment Alternatives Evaluations install should be made based on site visits to similar installations to observe the screens and talk to the operators of the equipment. For the purpose of developing a project budget, we have assumed that perforated plate fine screens will be included in the project. In addition, during final design a detailed hydraulic study should be developed for the screening area to determine if even finer screens (1/8-inch) could be installed. 6.03 BIOLOGICAL TREATMENT ALTERNATIVES ANALYSIS The Dubuque WPCP has employed high-rate HPO activated sludge since the mid 1970s. Most of the equipment still in use is original, and a significant upgrade is required to continue the use of the existing facilities. The section presents three alternatives for biological treatment at the Dubuque WPCP. A. Description of Alternatives Three biological treatment alternatives will be reviewed in this analysis. These include: ^ B1 HPO activated sludge; new mixers and controls; hauled liquid 02 (existing system). ^ B2 HPO activated sludge; new mixers and controls; on-site 02 generation. ^ B3 Air activated sludge; expand tankage; new blowers and diffusers. ^ B4 MBBR activated sludge; expand tankage; new blowers and diffusers. Each of the alternatives assumes continued use of the existing primary clarifiers to provide approximately 25 percent BODS removal upstream of the biological treatment facilities. In addition, the existing final clarifiers, RAS pumps, and WAS pumps will be reused. Future nutrient removal requirements are considered in the nonmonetary considerations portion of this discussion. Alternative B1-Upgrading Existing HPO System. This alternative continues the use of HPO activated sludge with oxygen hauled to the plant by trucks. No additional aeration tank volume is required for this alternative, but all equipment would be replaced and/or upgraded to provide improved reliability and energy efficiency. The following elements are included: 1. Conduct concrete testing on the aeration basin structure and concrete deck to determine condition; repair as require. 2. Seal concrete deck to minimize oxygen loss. 3. Replace the 27 mixers (9 per train) with new surface mixers. The new mixers are estimated to have a connected power of approximately 300 hp and an average operating power of about 260 hp. 4. Replace vent pressure and volatile organics monitoring and control equipment. 5. Implement DO monitoring for improved control. Prepared by STRAND ASSOCIATES, INC.® 6-4 RAW:ebt\S:\@SAI\1 51-2 0 011 54\002\WrdlReport\S6.doc\052708 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section frWastewater Treatment Alternatives Evaluations 6. Continue purchasing liquid oxygen and hauling oxygen to the plant. The 02 storage facility is leased from the oxygen supplier, and upgrades required for this alternative will be implemented by the supplier. Alternative B2-Upgrading Existing HPO System and On-Site 02 Generation. This alternative is similar to Alternative B1 except that the plant would generate oxygen on-site using pressure swing adsorption (PSA) or vacuum-pressure swing adsorption (VPSA) equipment (collectively termed V/PSA). The following elements are included in this alternative: 1. Conduct concrete testing on the aeration basin structure and concrete deck to determine condition; repair as require. 2. Seal concrete deck to minimize oxygen loss. 3. Replace the 27 mixers (9 per train) with new surface mixers. 4. Replace vent pressure and volatile organics monitoring and control equipment. 5. Implement DO monitoring for improved control. 6. Install a new V/PSA in the existing space previously occupied by the cryogenic oxygen generation equipment. One unit would be provided to meet maximum month oxygen demands of 15 to 18 tons/day and would have aturn-down capacity to allow efficient oxygen generation at the near future typical demand of approximately 8 to 9 tons 02/day. The approximate average power for this equipment is 200 to 250 hp at future design conditions. 7. The V/PSA may be owned by the City (Alternative B2a) or leased from the supplier (Alternative B2b). 8. The existing backup liquid oxygen system would continue to be leased. Alternative B3-Diffused Air Activated Sludge. This alternative presents a significant change to the existing HPO activated sludge system and includes conversion to more conventional air activated sludge to provide biological treatment. Average design BODS loading rates of approximately 30 Ibs/1,000 ft3/day were used to develop the required additional aeration basin volumes for this alternative. The following modifications are required: 1. Construction of approximately 6.9-million gallons of aeration basin volume and demolition of the existing shallow HPO basins. The new basins would have a minimum side water depth of 20 feet because of limited site availability whereas the existing basins only have a side water depth of 12 feet. The construction of the new tanks and demolition of the existing tanks will need to be phased to provide continuous biological treatment. Prepared by STRAND ASSOCIATES, INC.® 6-5 RAW:ebt\S:\@SAI\151-200\154\002\W rd\ReportlSB.doc1052708 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 6-Wastewater Treatment Alternatives Evaluations 2. Installation of fine membrane diffusers and associated piping and controls within the new aeration basins. 3. Installation of five new centrifugal aeration blowers in the existing HPO building space to provide an average design air flow rate of approximately 10,000 scfm and a maximum day air flow rate of about 24,000 scfm. For preliminary design purposes, we have assumed 5 or 6 new blowers with a total connected power of approximately 2,000 hp. The average design operating power is approximately 430 hp. Alternative B~MMBR Activated Sludge. This alternative is a modified version of Alternative B3 and also represents a significant change from the existing activated sludge system. hange to the existing HPO activated sludge system and includes conversion to more conventional air activated sludge to provide biological treatment. Average design BODS loading rates of approximately 30 Ibs/1,000 ft3/day were used to develop the required additional aeration basin volumes for this alternative. The following modifications are required: 1. Construction of approximately 1.3-million gallons of aerated MMBR basin volume upstream of the existing HPO basins. Medium bubble aeration diffusers would be used to transfer oxygen into the wastewater. Plastic media would be included in these basins to develop a population of attached-growth bacteria to increase solids retention time. The new basins would essentially be used as a roughing stage to reduce the loadings to the existing basins. 2. Installation of fine membrane diffusers and associated piping and controls within the existing aeration basins. 3. Installation of new centrifugal aeration blowers in the existing HPO building similar to Alternative B3. B. Monetary Comparisons Table 6.03-1 summarizes the present worth analysis for each of the alternatives. A detailed summary of the total present worth of each alternative is included in Appendix D. Based on this analysis, Alternative B1-HPO with Liquid Oxygen has the lowest capital cost opinion at approximately $4.5 million, followed by Alternative B2b-HPO with Leased V/PSA at $6.5 million. Alternative B2a has an opinion of capital cost of approximately $8.4 million, and Alternative B3-Air Activated Sludge has the highest projected capital cost at nearly $15 million. Prepared by STRAND ASSOCIATES, INC ® 6-6 RAW:ebt\S:1@SAI\151-200\154\002\WrdlReport\S6.doc\052708 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 6-Wastewater Treatment Alternatives Evaluations Alt B1 ____~.a_~~~. ~__ __ _ ( __Alt B2a ~e_e Alt B2b .t.~.__ .._~_-~~._. ~ .. _ Alt B3 _ ,_.~ ~F..,_ ,_.... - _. Alt 64 ,~~r_.__ ___._.__. ,.._ _ HPO with _ Trucked-in HPO with HPO with MBBR Air Liquid City-Owned Leased Air Activated Activated Oxygen :.. _ V/PSA ....... __ V/PSA _.. _._ _.... _ Sludge _.. _ _.... _ Sludge . z f Opinion of Capital Costs ,_-., . _.~er ~.____. ~_ ____._v.___n _~~. __r.~.___.___ . _. $4,527,000 .._ ._, ~.__ .~...~ __ ...$8,,388,000, ..._ _. _ v__ ~. _ ._ _$64982000 _ ._ _~_~_r~_ ~._.~.._ _$142567,000 .~~___,._.~. __~v_. ~e~ $13,963,000 .._ __ ___ _ ~ .....~ ~. Annual O&M Costs Labor -- $83,000 $104,000 $42,000 $83,000 $83,000 , ____ „_, Aa~_,__ ~wM ~ Maintenance _v _ _ _ _ $40 000 _~~ _ $78,000 a_ __ ___ , __ $40,000 m_,_ _ ~ $43,000 __ _ _$57,000 _ Llquld 02/Lease Fee $501,000 $19 000 $325,200 $0 $0 Power $136,000 $251,000 ~ $251,000 $225,000 $225,000 .~ Subtotal Opinion of Annual O&M' _ $760,000. [ _ $452,000 _ $658,000. ~ - m $351,000 - _ $365000 _~__~ ~,_ __.___~_. _~ __ ..- __ _ ~. -_ Present Worth of O&M 1 $9,572,000 $5,693,000 ~ $8,288,000 ~ ,~~_.~. _. _ $4,421,000 __ _...,__ ~... -. __. $4,597,000 Present Worth of Future E ul ment _ $196,000 $196,000 $196,000 481,000 _ $2 122,000 .~ _n _ Present Worth of Salvage ($241,000) ($268,000) ~ ($268,000) ~ ($1,139,000) I _ ($1,422,000) ~ _ TOTAL OPINION OF PRESENT =WORTH' $14,054,000 _~ ~. _ $14,009,000 $14,71.4,000 $18,330,000 ~ _ $19 260,000,_ . ~ ~ Notes i ' Project life 20 years discount rate 4 875%. Table 6.03-1 Biological Treatment Opinion of Present Worth Summary However, based on annual O&M cost opinions, the order is reversed in that Alternative B3 has the lowest projected annual O&M cost whereas Alternative B1 has the highest. This indicates that to maintain the existing facilities will result in the lowest up-front costs and highest annual O&M costs of the four alternatives. The 20-year present worth cost opinions of Alternatives B1, B2a, and B2b are all within approximately 5 percent of each other, which is considered equal for the purposes of this evaluation. Alternative B3- Air Activated Sludge has a projected present worth cost that is approximately 32 percent greater than the low-present-worth-cost alternative (B2a). C. Nonmonetary Considerations All systems provide reliable treatment for BOD and TSS. Should future efFluent nutrient limits be implemented in the NPDES permit, the air activated sludge process is more adaptable to biological nitrogen and phosphorus removal processes. One main advantage that HPO activated sludge has over air activated sludge for this application is that it requires considerably less space on the site. The site restrictions are significant, as the entire plant is only about 20 acres, which is very small for this size facility. Continuing with HPO activated sludge, therefore, provides better flexibility with respect to site constraints over air activated sludge. More specifically, Alternative B1-HPO with Liquid Oxygen provides the additional advantage of limiting the investment in the existing infrastructure, which could be important should very strict effluent nutrient limits be imposed in the future at the plant. Prepared by STRAND ASSOCIATES, INC.® 6-7 RAW:ebt\S:\@SAI\151-200\154\002\WrdlReport\S6.doc1052708 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section f~Wastewater Treatment Alternatives Evaluations From an overall energy balance among the alternatives, there is not aclear-cut best alternative. All of the systems evaluated are among the most efficient in terms of power required per unit of BOD removal provided because of the high oxygen transfer capacity of these systems. Therefore, for the purpose of "green" comparisons, all the alternatives are approximately equal. D. Environmental Considerations (Future NPDES Permit Issues) The costs for the air activated sludge treatment system are significantly higher on the bases of capital and present worth costs. However, air activated sludge does offer the following advantage over the HPO alternatives-air activated sludge provides improved capacity and flexibility to meet future ammonia and/or total nitrogen limits. In addition, biological P removal is likely simpler to implement with air activated sludge compared to HPO systems. While the air activated sludge system has certain advantages over HPO systems with respect to nutrient removal, the HPO system can be modified to some degree to improve the ability to implement nutrient removal as well as to lower operating costs. For example, since the HPO basins are relatively lightly loaded compared to typical design of HPO systems, the last one or two stages (nine stages per train) could have the concrete covers removed and operate as air activated sludge basins. This provides the following benefits: 1. Lowers liquid oxygen requirements (or generated oxygen requirements), since the oxygen required for those stages will be supplied from the air. 2. Releases carbon dioxide and increases pH, which would allow the plant to more easily meet the anticipated future pH limit. 3. Results in lower DO levels for those stages, which may allow an internal recirculation loop to be integrated into the HPO system to affect some level of biological nitrogen and/or phosphorus removal. E. Recommended Biological Treatment Alternative Based on these preceding evaluations, we recommend that Alternative B1-HPO Activated Sludge with Hauled Liquid Oxygen be implemented. This alternative provides the lowest capital cost alternative and lowest 20-year present worth costs as well. Because of the lower capital costs, the investment in the existing infrastructure is lower than the other alternatives, which provides more flexibility if future nutrient limits require major changes at the plant. We also recommend modifying the existing HPO system to enable operation of the last one or two stages under ambient air conditions. This should further reduce oxygen use and associated trucking costs and fuel usage and will also raise the effluent pH to some degree. Prepared by STRAND ASSOCIATES, INC ® 6-8 RAW:ebt1S:\@SAI\151-200\154\002\Wrd\ReportlS6.doc\052708 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 6-Wastewater Treatment Alternatives Evaluations 6.04 EFFLUENT DISINFECTION ALTERNATIVE ANALYSIS Disinfection is currently required at the Dubuque WPCP from April 15 through October 15 to reduce the presence of fecal coliforms in the treated effluent. Current regulations mandate a fecal coliform plate count of less than 200 CFUs per 100 mL. More stringent regulations are likely to be included in the next NPDES permit and will require disinfection to achieve a maximum daily plate count of less than 235 E. coli per 100 mL. Disinfection .will also be required from March 15 through November 15. The disinfection alternatives will each be sized to meet the future E. coli limits at a peak flow of 30 mgd. While the projected peak hourly flow to the WPCP is 40.9 mgd, because of the implementation of flow equalization using the existing trickling filter structures, the anticipated peak flow at the disinfection facilities is only about 25 to 30 mgd. A. Description of Alternatives The following disinfection alternatives are considered for the Dubuque WPCP: ^ D1 New chlorine gas system equipment ^ D2 Liquid sodium hypochlorite ^ D3 On-site hypochlorite generation ^ D4 Ozone ^ D5 Ultraviolet disinfection Alternative D1-Chlorination with Chlorine Gas is essentially an equipment replacement project at the Dubuque WPCP. The plant currently disinfects effluent wastewater with chlorine gas followed by dechlorination with liquid magnesium bisulfite. Both of these unit processes would continue. All the gaseous chlorine control equipment would be replaced with new equipment. In addition, a new caustic scrubber would be installed to evacuate the chlorine gas storage area and the control room in the event of a chlorine gas leak. The two existing chlorine contact tanks, each having a volume of 24,150 ft3, will provide adequate chlorine contact time throughout the design life of the facility. As noted in Section 5, the contact time at the peak hourly flow of 40.9 mgd is marginally less than 15 minutes. However, with the conversion of the trickling filter structures to equalization tanks, the peak flow through the disinfection system will be significantly less than 40.9 mgd, and the existing contact tanks will meet the Iowa Design Standards for chlorine contact time. Liquid magnesium bisulfite will continue to be added in the mixing chamber downstream of the chlorine contact tank for dechlorination to meet the maximum chlorine residual efFluent limit of 202 µg/L. The existing dechlorination system was added approximately 12 years ago and does not require replacement at this time. Alternative D2-Liguid Sodium Hypochlorite includes the replacement of the gaseous chlorine system with a liquid sodium hypochlorite system. Liquid hypochlorite solution would be delivered to the WPCP in tanker trucks and stored in bulk containers, similar to the existing dechlorination system. This analysis includes costs for- new liquid hypochlorite equipment including chemical storage tanks, metering pumps and accessories, controls and instrumentation. The liquid storage tanks would either be housed in the existing ton cylinder storage room at the headworks or potentially in the same building where the dechlorination storage tanks and metering pumps are installed. The required liquid storage Prepared by STRAND ASSOCIATES, INC ® 6-9 RAW:ebt\S:\@SAI\151-200\1541002\WrdlReport\S6.doc\052708 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 6-Wastewater Treatment Alternatives Evaluations volume is approximately 15,000 gallons to provide approximately 30 days of storage under the design average flows. This would include two 7,500-gallon FRP tanks and two or three metering pumps to deliver hypochlorite solution to the mixing chamber upstream of the chlorine contact tank. The existing dechlorination system would be maintained as in Alternative D1. Alternative D3-On-site Hypoch/orite Generation is identical to Alternative D2 except that liquid sodium hypochlorite solution would be generated on-site using electrolysis of a brine solution. On-site hypochlorite generation systems are more commonly used in water treatment, but they are gaining acceptance at wastewater facilities. Reportedly, the same level of treatment may be achieved with on- site or purchased hypochlorite solution. The primary advantage of this system is that it eliminates the transportation and handling of hypochlorite solution, although salt will still need to be trucked to the site. Also, since the hypochlorite is generated as-needed, degradation of the disinfecting power of the solution during storage is minimized. We have assumed that the equipment and storage tanks would be housed in the same building as the dechlorination facilities. As in Alternatives D1 and D2, the existing bisulfite dechlorination system would be reused. Alternative D4-Ozone Disinfection involves the removal of the existing chlorination and dechlorination systems and installation of an ozone generator, control system, off-gas destructor, and instrumentation. The feed gas to the ozone generator would be oxygen. The contact time for ozone would be similar to chlorine systems. Advantages of using ozone are essentially the same as other nonchlorine systems;, however, off-gases may be toxic and must be handled/monitored accordingly. The analysis includes costs for a complete ozone system installed in the existing dechlorination room in the HPO building. For the purposes of this evaluation, we have assumed that biological treatment will continue to be by HPO activated sludge and the source of oxygen will be as recommended in Section 6.03. Alternative D5-Ultraviolet Disinfection represents the state-of-the-art in wastewater disinfection systems. UV disinfection has gained popularity as a disinfection technology during the last two decades because it produces consistent results without the disadvantages of chlorine disinfection. These disadvantages include the need for dechlorination, potential concerns related to chlorinated compounds in the plant effluent, and safety concerns with handling chlorination and dechlorination chemicals. Capital costs related to implementation of UV disinfection at the Dubuque WPCP include construction costs for modification to the chlorine contact tank to provide a disinfection channel and equipment costs; including lamps, ballasts, and controls. The existing chlorination and dechlorination equipment would be removed from the site. Preliminary testing indicates the Dubuque WPCP effluent has a UV transmittance in the range of 60 to 70 percent, with an average of approximately 65 percent. This is a fairly typical range for application of UV disinfection technology. B. Monetary Comparisons Table 6.04-1 summarizes the present worth analysis for the five disinfection alternatives, and Appendix ~' ' E provides additional details of the monetary comparisons. Based on this analysis, Alternative D2- Liquid Hypochlorite has the lowest projected capital cost ($617,000) and present worth cost ($1,329,000) of the five alternatives. Gaseous chlorination (Alternative D1) is approximately 20 percent Prepared by STRAND ASSOCIATES, INC ® 6-10 RAW:ebt\S:\@SAI\151-200\1541002\WrdlReportlS6.doc\052708 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section C~Wastewater Treatment Alternatives Evaluations TABLE 6.04-1 DISINFECTION OPINION OF PRESENT WORTH SUMMARY - -- _ --w ~._~ - - -- .~_.x _~...W___ _~.__~... _ Alt. D1 .~..____--._~.._~ _-~ Alt. D2 --- - ------- ------ Alt. D3 ~ ----__._ ~- Alt. D4 --_~~_~v_~-n__.____ Alt. D5 On-site Gas Sodium Sodium Ultraviolet Capital_Cost ,,. r Chlorination Hypochlorite Hypochlorite Ozonel Disinfectlon2 _. Egwpment _ ~ $320,000 $103,000 $539,000 _ ~ $1,781,000 $821,000 _ _, ._ wChemlcal_StorageN_-- _ ____._..~___.___.______ _____ ,~______$0 ___„ $68,000 _ $120,000m w.__ __-_ __-_$0-- _---.. v.~__ __~~ Structural $20,000 ~ $125,000 $75,000 $75,000 $80,000 i _w.... _. _ __ ....- . -.__~~ e_.~_.~m_...____ . --- .. _ w._.. Mechanical . __~._. ~_ ..~,. ___. $75,000 _.._Y _ ~ _ _ ~ ~ ~ $53,000 ....._ .__ ._..__ _~ _ $132,000 __~.__ ~ _ ~____ _..n.~ _ $334,000 _a ~~ $108,000 Electrical ~ $68,000 $59,000 $147,000 $371,000 $180,000_ ~ Slte Work ,Y_ $24,000 _ $15,000 _ ~ $37,000 ~ __ $93,000 $45,000 2_ ~_ ,___ :_~=T : _ __ _ Subtotal _ ~~t_ ~ $507,000 __ _ ~_ _ ~ $423,000 _ _ ~ _$1,050,000 _r _ $2,654,000 $1,23.4,000 . __ General Condltlons @ 8% ____ -_ __ 4 _ _ ~, _„_$41,000_ [ -_: $34,000 _ ~ __ $84,000 ~__ $212,000 _ ~ $99,000 s _ Subtotal _~~ _ _ $548,000 y_ $457,000 ~ __$1,134,000 , $2,866,000 __ $1,333,000 , ~_~. Englneermg_+ Contingencies @ 35%ss -.$192,000 _.$160,000 _ ~ $397,000-- .____. _ ~ ~ ~ ~ $1,003,000 .. 467,000 ~ _. s_~~~~...~..__,..m. Subtotal Opinion of Capital Costs $740,000 $617,000 $1__,53.1,000 $3,869,000_ $1,800,000 ~ AnnualO&M Costs Labor $15,000_ - _-_--_-- $15,000._ __-.--$20,000 :-_ _~__y~~_- _- -_$20,000_.,- -_ . -_$15,000 Chemical Costs_ _ _:__ ___ _____ _ _ „_ _ $33,000_ __ __$35,000_ $18,000 ___ _ $6,000_, __ --_ __$1,000w Maintenance $14,000 --- __ $7,000 __ $22,000 __ $36,000 $18,200 Power ~w --- --- --- $700 ~ _ $700 -_ $8,000 $53,000 ~ $12,000_ Subtotal Opinion of Annual O&M3 _ _ $63,000 _$58,000 $68,000 $115,000 $46,000 __Present Worth of_O&M _ _ _ ~ _ $781,000_ , e_ $731,000 _ _$856,000, _$1,448,000 $582,000 Present Worth of Future Equipment_ $116,000 $37,000 $195,000 ~. $646,000 __ $286,000 Present Worth of Salvage __ __ _ $94,000 $56,000 $166,000 $506_,000 $239,000_ _ _ TOTAL OPINION OF PRESENT WORTHS _~ _ ... $1,543,000 _ $1,329,000 $2,416,_000 $5,457_ ,000 $2,429,000 e. Notes ,_ 1 O&M cost is assumed at 2% of capltal cost m ..-- _ 2 Maintenance cost includes lamp_replacement __ _,.a__ _ _.~ ___ -_- . _- __~_~ ____._ __,_~ _.: _. _..___ _ __ ___ _ _-- ~..-- s Project Ilfe_= 20 years; discount rate 4 875%. _ ~ _ _ ~ ___ Prepared by Strand Associates, Inc ° Page 1 of 1 RAW:ebt1S:\@SAI\151-200\154\002\Wrd\ReportlTable 6.04-1.doc1052708 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section f~Wastewater Treatment Alternatives Evaluations higher on a capital cost basis and 16 percent higher on a total present worth basis. Alternatives D3 (on- site generation) and D5 (UV) have considerably higher capital cost and total present worth cost projections. The ozone disinfection alternative has a projected capital cost and present worth cost that is more than double the next lowest cost alternative. Based solely on monetary costs, continued chlorination (either gaseous or liquid) followed by liquid dechlorination represent that lowest cost alternative. These two alternatives (D1 and D2) would result in the lowest impacts on user rates. C. Nonmonetary Considerations and Environmental Considerations Nonmonetary issues must also be considered when evaluating disinfection alternatives. The vast majority of wastewater treatment plants use either chlorination/dechlorination or UV disinfection systems. On-site hypochlorite generation is becoming more common but its use is still significantly less than either chlorination or UV disinfection. Ozone is not used regularly in the wastewater industry, though it has seen more application in the water treatment industry. The City of Dubuque has a strong desire to reduce chemical usage at the plant. Chlorine, even at low concentrations, is toxic to fish and other biota, and potentially harmful chlorinated hydrocarbons may be formed by the oxidation of organic compounds by chlorine in the disinfection process. UV disinfection has the following additional advantages: 1. Lowest opinion of annual O&M costs of the five alternatives. 2. Eliminates safety concerns with respect to the storage and handling of chemicals such as chlorine gas, liquid hypochlorite, liquid bisulfate, and ozone as UV disinfection is the only alternative to eliminate the use of chemicals. 3. Eliminates concerns of on-site and off-site exposure to chlorine gas. 4. Eliminates concerns for the uncertainty of chlorine usage for wastewater disinfection in the future. 5. Eliminates concerns regarding the potential toxicity of chlorine compounds on aquatic life and the need for chlorine residual monitoring. 6. Eliminates the concerns of potential off-gassing from ozonation process. 7. Provides more than 20 years of use in the wastewater treatment industry. In addition to the benefits of UV disinfection provided above, UV disinfection may also be considered a "greener" technology from an energy perspective. Chlorine production is relatively energy intensive, and the overall energy requirements to produce chlorine and transport it to the site are greater than the energy use from a UV disinfection system. Therefore, based on energy use, implementing UV Prepared by STRAND ASSOCIATES, INC ® 6-11 RAW:ebt1S:\@SAI\151-200\154\002\W rd\ReportlS 6.d oc\052708 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 6-Wastewater Treatment Alternatives Evaluations disinfection better meets the City of Dubuque's top priority of implementing sustainable programs and establishing itself as a "Green City." D. Recommended Disinfection Alternative Based on the evaluations presented above, Alternative D5-UV Disinfection is recommended for implementation at the Dubuque WPCP. While the monetary costs to implement this technology are higher than maintaining the chemical systems needed for chlorination and dechlorination, UV disinfection has numerous nonmonetary and environmental benefits and better meets the goals of the City of Dubuque. 6.05 RESIDUALS MANAGEMENT ALTERNATIVE ANALYSIS The current residuals management system includes primary sludge storage, WAS storage, blended sludge storage, centrifuge dewatering, dewatered cake conveying and pumping, fluidized bed sludge incineration (two units, one with one recuperator), and ash ponds. In addition, scum and grease from the primary clarifiers is handled separately with the intent of directly injecting this material into the incinerators. The scum and grease handling system has been difficult to manage. The incineration facilities are nearly 40 years old and have undergone some upgrades. The dewatering facilities are approximately 15 years old. The existing residuals management system requires considerable maintenance and repairs to keep it operational at this time and retaining incineration will require major capital investment. Therefore, it is appropriate to consider other alternatives. A. Description of Alternatives The following residuals management alternatives are included in this evaluation and described below: ^ RM1a Major rehabilitation of both existing incinerators. ^ RM1 b Major rehabilitation of one incinerator; no rehabilitation of the second unit. ^ RM2a Major rehabilitation of one incinerator with lime stabilization for backup. ^ RM2b One new incinerator with lime stabilization for backup. ^ RM3 Lime stabilization with agricultural land application. ^ RM4 Anaerobic digestion with agricultural land application. ^ RM5 Anaerobic digestion with composting. ^ RM6 Anaerobic digestion with drying and agricultural land application. ^ RM7 Drying with agricultural land application. The evaluation of each of these management alternatives is based on continued primary treatment and secondary biological treatment using the HPO activated sludge system. The design sludge quantities for this alternative are 46,900 Ibs/day (dry weight basis) at the future maximum month condition, which includes approximately 26,500 Ibs/day of primary sludge, 20,400 Ibs/day of WAS, and an assumed 10 percent recycle loading. Power usage, labor costs, chemical costs, and residuals disposal costs are considered in the analysis. Based on available data, the metals concentration in the residuals are low enough for land application as either Class I or Class II biosolids if appropriate stabilization is provided. Prepared by STRAND ASSOCIATES, INC ® 6-12 RAW:ebt\S:\@SAI1151-200\154\0021W rdlReportlS6.doc\052708 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section f~Wastewater Treatment Alternatives Evaluations All alternatives include the use of centrifuges for dewatering either raw sludge or digested biosolids. With respect to the centrifuges, one of the two existing units will remain, and the other will be used for spare parts. Two new centrifuges will be installed to provide three operating centrifuges for improved redundancy and reliability. For the alternatives that include land application, we have assumed the removal of biosolids from the WPCP, storage requirements for biosolids, and land application of the biosolids on agricultural land will be provided by a third-party contractor. Two contractors were contacted and both indicated they would be willing to construct off-site storage and develop an extended-term land application program for the City of Dubuque. This method of biosolids disposal is desired in this case as the WPCP site does not have excess space to store biosolids or hauling equipment, and the City does not have a history with land application in the area. Alternative RM1a-Major rehabilitation of the two existing incinerators. This alternative includes major rehabilitation of the 40-year-old incinerators and replacement of all major incineration equipment and controls. A recent inspection of the incineration facilities indicated the need to significantly rehabilitate the equipment and structures if continued use of the fluid bed incinerators were to continue. Residuals management upstream of the fluid bed incinerators would also be modified. Dewatering of the raw blended sludge requires the primary sludge percentage to be near 58 to 60 percent for improved dewatering and efficient incinerator operation. Because of the highly soluble raw wastewater, however, the WAS production is too high to meet this requirement. Therefore, some form of WAS reduction is required for this alternative. WAS reduction could be implemented by any of the following methods: 1. Operating the HPO activated sludge systems at a longer sludge age to reduce the observed biological yield. This will require more oxygen for endogenous decay of the biological sludge. In addition, the plant has experienced filamentous problems when operating at longer sludge ages, so additional controls would be required to manage filamentous bulking events. 2. Constructing aerobic digestion facilities for WAS. The existing WAS holding tank only provides a detention time of 4.5 days at the future design loadings. An additional detention time of about 15 days would require a tank volume of 1.6-million gallons and significant blower horsepower to provide adequate aeration. Siting such a tank at this site will be difficult. 3. Installing a WAS minimization system that uses ozone to lyse cells and reduce WAS by as much as 80 percent. The additional oxygen required to oxidize the soluble BOD generated from cell rupture is met by the ozone reduction to oxygen. There are a few companies marketing this technology, though there are no known full-scale installations in the United States. This system would also utilize additional oxygen in the ozone generator. Prepared by STRAND ASSOCIATES, INC ® 6-13 RAW:ebt1S:1@SAI\151-200\154\002\W rdlReportlS6.doc\052708 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section f~Wastewater Treatment Alternatives Evaluations The construction of aerobic digestion facilities is not deemed to be feasible without sacrificing much of the remaining space on the site. Installing an ozone sludge minimization system may be feasible, but it will require considerably more evaluation prior to making the decision to install such a system. Operating the activated sludge system at a longer sludge age is feasible, especially since the third train will be available rather than only two trains of aeration basins. This alternative is included for this evaluation. However, should one of the incinerator alternatives be selected, the potential to use the ozone WAS minimization technology may be considered further. This alternative includes the following elements directly related to the fluid bed incinerators: 1. Replacing refractory lining in incinerators and ductwork. 2. Repairing steel shells of both incinerators. 3. Replacing all controls. 4. Replacing all pumps and fans. 5. Retrofitting existing scrubbers with new scrubber internals. 6. Replacing internal tubes on existing recuperator (north incinerator) and install one new recuperator (south incinerator). 7. Constructing a building addition (approximately 4,000 ft2) to house the new recuperator for the south incinerator and provide improved constructability in the incinerator space. In addition, prior to incineration, the sludge management elements include the following: 1. Retrofitting the WAS holding tanks with new aeration diffusers and piping. 2. Replacing the existing WAS storage tank blowers with three new blowers in the headworks building provided to replace the existing units. All of the existing equipment and piping is in very poor condition. 3. Providing primary sludge and WAS flow meters. 4. Providing a new, larger sludge blending tank and mixing equipment. 5. Providing three new centrifuge feed pumps. 6. Installing two new centrifuges; reuse one of the existing centrifuges with new back drive; remove the existing belt filter press (BFP). 7. Replacing the dewatered cake belt conveyors with enclosed screw conveyors. Prepared by STRAND ASSOCIATES, INC ® 6-14 RAW:ebt\S:\@SAI\151-200\154\0021Wrd1Report\S6.doc1052708 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 6-Wastewater Treatment Alternatives Evaluations 8. Refurbishing the high-solids hydraulic piston pump to convey dewatered cake to the incinerators. 9. Installing one new high-solids hydraulic piston pump for redundancy. 10. Installing new grease/scum concentration equipment and modify scum management. This alternative would provide improved overall redundancy over the existing incineration system. Currently, only the north incinerator has a recuperator (exhaust stack heat recovery), which significantly lowers energy usage and requires only a small amount of fuel to sustain combustion. The existing south incinerator, when used, requires considerably more fuel and is much more expensive to operate. Ash will continue to be pumped to the ash ponds for dewatering and temporary storage. Alternative RM1b-Major rehabilitation of one incinerator; no rehabilitation of the second unit. This alternative is similar to RM1a except that only the north incinerator would be rehabilitated. The south incinerator would continue to function as a standby and no upgrades would be made for this unit. It is understood that this alternative is not directly comparable to the other alternatives in terms of overall system reliability, since a 40-year-old incinerator would serve as the standby unit. Alternative RM2a-Major rehabilitation of one incinerator with backup lime stabilization. This alternative includes a major rehabilitation of the south incinerator and demolition of the other incinerator. A backup lime stabilization system would be installed to provide Class I biosolids for times when the incinerator is off-line. We have assumed that the lime system will be utilized for one month each year to allow maintenance of the incinerator. We have assumed that these biosolids would be contract hauled to agricultural sites or other third-party-provided off-site storage on an as-needed basis. A unit cost of $28/wet ton was assumed, which is significantly higher than comparable off-site storage and land application costs in the Dubuque area. The higher costs were used since the land application operations will be intermittent and could be at irregular intervals. This alternative includes the following elements related to the fluid bed incinerator and backup lime system: 1. Remove the existing north incinerator and associated equipment, materials, and structures. 2. Rehabilitate the south fluid bed incinerator, as well as the existing recuperator, scrubber, and all required equipment and controls. 3. Install one new lime stabilization system. For the purposes of this evaluation, we have based the system requirements on the Schwing-Bioset system, which utilizes lime and small amounts of acids to generate Class I biosolids. This system includes the required lime and acid storage and feed systems, contact reactor, high-solids hydraulic pump, odor control system, and required controls. This system is anticipated to be installed within the existing sludge processing building. Prepared by STRAND ASSOCIATES, INC ® 6-15 RAW:ebt\S:\@SAI\151-200\154\002\WrdlReportlS6.doc1052708 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 6-Wastewater Treatment Alternatives Evaluations 4. Install a small, covered storage pad to hold approximately one week of lime-stabilized biosolids. Prior to incineration or lime stabilization, the sludge management elements are identical to that of Alternative RM1, except that the redundant high-solids piston pump is already included above. For 11 months of every year, the incinerators will destroy the volatile solids, and ash will be pumped to the ash ponds, resulting in very low final solids disposal costs. For one month of every year, the expected average biosolids production would be approximately 49,400 Ibs/day (dry weight), which includes the raw sludge solids of about 30,000 Ibs/day (average over 20-year period) and a lime dose of approximately 65 percent on a dry weight basis. This amounts to an average of approximately 67 wet tons/day of biosolids hauled to the remote site. Alternative RM2b-One new incinerator with backup lime stabilization. This alternative is similar to Alternative RM2a except that both existing fluid bed incinerators and all appurtenant equipment would be removed, and a new fluid bed incinerator with backup lime stabilization system would be installed. The other elements are essentially identical to Alternative RM2a. Alternative RM3-Lime stabilization with agricultural land application. Lime stabilization is a process that achieves pathogen reduction by exposing the bacteria in the biosolids to an elevated pH. Addition of lime to dewatered biosolids also causes a temperature increase. This process can be used to produce Class I or Class II biosolids, depending on the pH and temperature achieved and the detention time. One drawback to this stabilization method is the increase in the volume of solids generated from lime addition. For the purposes of this evaluation, the Schwing-Bioset system was used to develop project costs, with the assumption that Class I biosolids would be produced. This system would have redundant reactors and high-solids feed pumps and would be installed within the sludge processing building, similar to Alternative RM2. Significant odor control capabilities would be required to minimize the potential of ammonia odor from this high pH system. We have assumed that these biosolids would be contract hauled to agricultural sites or other third-party-provided off-site storage on an as-needed basis. A unit cost of $20/wet ton for contract biosolids hauling, storage, and disposal was assumed based on discussions with two local contractors. A lease fee for athird-party-owned storage facility would be included with an option to purchase the facility after a 5- or 10-year period. Upstream sludge management would be similar to Alternatives RM1 and RM2, except that WAS minimization would not be as critical and systems to reduce WAS are not included. Alternative RM~Anaerobic digestion with agricultural land application. Anaerobic digestion has been used for decades to stabilize sludge prior to land application. Temperature phased anaerobic digestion (TPAD) is a high-rate digestion system that stabilizes biosolids in a two-step process where the sludge is first held for a minimum of five days under thermophilic conditions (131 °F) before being held for a minimum of ten days under mesophilic conditions (95°F). TPAD designs allow for a higher volumetric loading rate than standard mesophilic digestion. Design volumetric loadings of over 200 Ibs VS/1,000 ft3/day are possible with this process. Prepared by STRAND ASSOCIATES, INC ® 6-16 RAW:ebt\S:\@SAI\151-200\154\002\WrdlReportlS6.doc\052708 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 6-Wastewater Treatment Alternatives Evaluations Implementation of anaerobic digestion would require the construction of four new anaerobic digesters and a central control building, likely adjacent to Julien Dubuque Drive on the west side of the site. Two of the digesters would typically operate as thermophilic digesters with fixed covers, and the other two would operate as mesophilic digesters with gas holding covers. Each digester would be approximately 70 feet in diameter and 30 feet tall. The digestion system would normally operate in the TPAD mode, with sludge being delivered from the sludge blending tank to the thermophilic digesters first and then to the mesophilic digesters. From there, stabilized biosolids would be pumped to the centrifuges for dewatering. A small structure would be constructed to temporarily store biosolids, and disposal would be by contract hauling to an off-site storage facility and ultimately to agricultural land application. A unit cost of $20/wet ton for biosolids contract biosolids hauling, storage, and disposal was assumed based on discussions with two local contractors. A lease fee for athird-party-owned storage facility would be included with an option to purchase the facility after a 5- or 10-year period. The anaerobic digestion process produces biogas, which contains about 60 to 65 percent methane and can be collected and burned to provide heat for boilers or fuel for electricity and heat cogeneration. The anaerobic digestion process requires heat to maintain temperatures in the digestion tanks, and this heat consumes a significant amount of the biogas produced in the process. Analysis of anticipated biogas production rates indicates the biogas produced in the process will exceed the digester heating requirements even under the coldest weather conditions at current and future design loadings. Biogas reuse would include one of the following options: Option 1: Burn the biogas in a boiler to produce heat for the digestion process and for building heating needs. This option would utilize a portion of the biogas to generate heat, and the excess biogas would be flared. No supplemental natural gas would be required on a year-round basis to heat the digester or the new digester control building. During the warmer months of the year, a significant portion of the biogas would be flared. The current heating needs of the digesters and the new building are anticipated to be approximately 0.9 and 2.6 MBtu/hr during summer months and winter months, respectively, and the future design heating needs are projected to be approximately 1.4 and 3.1 MBtu/hr, respectively. By comparison, the anticipated heating value of the biogas produced is approximately 3.6 MBtu/hr under current loadings and 6.5 MBtu/hr at future design loadings. Therefore, if Option 1 is implemented, the amount of excess biogas will be adequate to consider additional energy recovery systems such as providing heat in other buildings. Option 2: Use the biogas to generate electricity and recover waste heat to provide some of the heating needs of the digestion process. Option 2 uses nearly all of the gas year-round to produce electricity. At the current average loadings, approximately 250 to 275 kW (335 to 370 hp) of electricity could be produced on a continuous basis. At future design loadings, approximately 400 kW (535 hp) could be generated. Waste heat recovery systems could recover approximately 1.2 MBtu/hr from the 250 kW system and 1.6 to 1.8 MBtu/hr from the 400 kW system. Compared to the heat demands for the digesters and building during much of the year, Option 2 would require the purchase of natural gas to supplement the heating needs of the facilities. Prepared by STRAND ASSOCIATES, INC ® 6-17 RAW:ebt1S:\@SAI\151-200\154\002\WrdlReportlS6.doc\052708 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 6-Wastewater Treatment Alternatives Evaluations The decision of whether to include electrical generation will be made during final design. However, based on preliminary calculations, it appears that Option 1 has a lower present worth cost and will be included in the overall present worth analyses. This option also has the following benefits: 1. Biogas quality can significantly impact beneficial reuse opportunities and costs, especially when used for electrical generation. Since the Dubuque WPCP does not currently produce biogas, the quality of the future biogas is unknown. Option 1 will allow the City to determine biogas quality and then design an appropriate gas conditioning system for beneficial reuse. 2. Electrical generation (Option 2) could be provided with engine generators or with microturbines. The status of microturbines for electrical generation is still questionable. While several plants in the Midwest (and elsewhere) are using microturbines, the equipment maintenance costs and equipment life have been higher and shorter, respectively, than originally anticipated. 3. The performance of the anaerobic digestion system can be measured and the quantity of biogas produced can then be more accurately assessed. This will allow the design of a future electrical generation system to better match the amount of biogas generated at the time, which will result in more efficient use of the renewable energy. 4. Option 1 is simpler to construct and operate. In addition, the initial construction cost for Option 1 is anticipated to be approximately $1 to $2 million less than the cost of Option 2, depending on the level of gas treatment required. 5. Option 1 could potentially be implemented with sale of excess biogas to a nearby industry. This potential has not been investigated in any detail at this time but is believed to have sufficient merit to be considered. Upstream of anaerobic digestion, the modifications previously described would be made to the WAS storage tank and aeration equipment, as well as the blended sludge storage tank. In addition, WAS thickening equipment would be included in the existing sludge processing building, including two thickeners (centrifuges assumed) and thickened WAS pumps. WAS thickening was included for all the anaerobic digestion alternatives (Alternatives RM4, RM5, and RM6). Finally, for the anaerobic digestion alternatives, the centrifuges would dewater digested biosolids in lieu of raw sludge. Alternative RM5-Anaerobic digestion with composting. This alternative is identical to Alternative RM4 in terms of capital improvements and modifications needed at the WPCP. The only difference is that dewatered biosolids would be hauled to the yard trimmings composting facility at the Dubuque Metropolitan Area Solid Waste Agency (DMASWA) site west of Dubuque. This facility processes yard trimmings and some food scraps (pilot study) using unaerated windrow-type composting. The finished compost is sold for $3/yd3 to local businesses and residents. We have included a biosolids disposal cost for this alternative of $35/ton, which includes the tipping fee (current yard trimming tipping fee _ $25.30/ton) and approximate transportation costs to the site. While this site is not currently regulated for biosolids, based on a site visit and discussions with Agency staff, there is land available and some Prepared by STRAND ASSOCIATES, INC.® 6-18 RAW:ebt\S:\@SAI\151-200\154\002\Wrd\Report\S6.doc\052708 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section f~Wastewater Treatment Alternatives Evaluations potential to cocompost biosolids with yard trimmings. In addition, since the biosolids would meet Class I standards, the regulatory requirements will not be as significant compared to biosolids only meeting Class II standards. We have not included any costs to construct additional buildings at the DMASWA site, nor have we included any costs associated with labor and maintenance at the facility. We have assumed that the higher than normal tipping fee would be required to help pay for the capital (buildings, equipment, odor control) and operation of the facility. To date, there has not been any significant discussion with respect to cocomposting of biosolids and yard trimmings, and this alternative will require considerably more evaluation and cooperation between the City of Dubuque and the DMASWA. If anaerobic digestion is selected for residuals management, the potential of such a facility should be discussed and evaluated in more detail. Alternative RM6-Anaerobic digestion with drying and agricultural land application. This alternative was included to reduce the amount of biosolids trucking from the site. The process is identical to that for RM4 and RM5, except that dewatered digested biosolids would be conveyed to dryers and dried to a solids content of about 90 percent. This eliminates nearly all of the water weight, resulting in significantly lower hauling costs and truck traffic. However, the operating cost for the dryers is relatively high for natural gas and electricity. Alternative RM7--Drying with agricultural land application. This alternative uses the same type of drying equipment as included in Alternative RM6, except that the dryer would receive raw sludge rather than digested biosolids. Therefore, the capacity of these dryers is required to be larger than the capacity of Alternative RM6. For both RM6 and RM7, dust control is required as sewage sludge dryers have had some serious problems with explosions caused by dust. In addition, odors from the dryer exhaust can be a problem and odor control systems would be required. B. Monetary Comparisons Table 6.05-1 summarizes the 20-year present worth analysis for each of the residuals management alternatives, and Appendix F provides additional details of these monetary comparisons. Based on this analysis, the lime stabilization alternative (RM3) has a significantly lower projected capital cost and a significantly higher projected annual O&M cost than the other alternatives. The incineration Alternatives RM1b and RM2a have the lowest projected present worth costs at about $29.4 to $30.6 million, and Alternative RM3 (lime stabilization) had the next lowest projected present worth cost at about $33.6 million (16 percent more than the lowest). Alternatives RM4 and RM5 (anaerobic digestion) have projected present worth costs that are approximately 23 percent higher than the low present worth cost. While the two incineration alternatives (RM1b and RM 2a) noted above have the lowest present worth costs, these two alternatives (especially Alternative RM1b) do not provide the same level of reliability and long-term serviceability (sustainability) as the other seven alternatives. This is because only one of the existing fluid bed incinerators would be rehabilitated for both of these alternatives, and the backup system (either a 40-year old incinerator or a lime stabilization system) would likely be called to operate more frequently than in the other alternatives. If the goal is to establish and implement the long-term solids management alternative at this time, these two alternatives should not be considered since Prepared by STRAND ASSOCIATES, INC.° 6-19 RAW:ebt\S:\@SAI\151-200\154\002\Wrd\Report\S6.doc\052708 y C O 7 W d v r_~+ Q C N d F ~. .4+ t0 d C O V Of C 10 V 1L C a w c 0 v C O a c~ o c~ 3 J 0o H v~ c 0 o 0 0 0 0 0 69 ~ rn ~n - d- 0 -- o 69 0 0 0 0 0 0 0 0 0 ~ ~ ~~~ ~ o ao o A rn o 0 0 0 0 o ~ pp ~ C U O M M C00 ti ~ ~ O N O N a C O O= Q J M N M 69 N E9 ~ 69 ~ E9 E9 M (O ~ (O b9 O ~ CA Q Q fR ~ E9 fA _d ~_.., ~ - ~___..__ ___.,__,r Q ~ U C f- ... . ~_.~. O O Y_.- __ --- O O _.., O O O O .__. N O ,._ O I~ .__.... d' W h ~ O Eg _----- O O ..._ -e. _ O O z.. O O e .-- ---- ~ -,...-_ O O , e_._.., O ~ ` ~ ~_ O +-• Z' -p ~ ~ ~~-Q. O O a0 N 0 a) 0 O ~ M d~ CO O f~ O CA O N O W ~ 0 N O CA ~ ` U Q C 7 C U O O O' CA M 'd' M O - CO O Of ~ M 0 0 r A f0 U ~ '~~- ~ 1~ M N d9 r N ER O M C a o Q 3 ~ ~ 69 69 6$ __ j 1 __.__ ,Wn__.._~.___ . _ ,= +-• ~ ___. ._... O O ~.___ _ Y. O O ~a~_ t O O --- O O --- ~- O - O 69 _-._ d' O __~.. O E9 ,_nPo.__.. O O __ _ O O __~~. O O ,_._ O _ ~ O I O -, ~ ~? ?~. C O N O O M 00 O O O ~ O ~ ~ O O ti N ~ ~ M ~ N ~ a ~p ~ ~ E9 69 O O EA ~ O ~ ~ O M O ~ ' C ~ O O O O O O O O N lA O E9 d' O O E9 O O O O O O O O O d ~ ~ Q O_ . j Cep ~ fop +~ O 00 N ^- O I~ CO O O M 0 ti M ~ ~ O r A O C'M CO O O ~ ~ d; O ti ~D _. U N O '?~ U f0 = 00 h W N ~ E9 E9 N M ~ 69 C h ~ O M ~ ~ O .. a Qo ~ Q ~ ~ ~ ~ ~ s C O O O O 0 O 0 N 0 O 0 (~) 0 O 0 E9 O O O O O O ~ o O M O ~ ~ O M 0 0 ~ CO O O O ~ O ~ ~ "'' 7 ~. N 03 ~_ .~ 'O ~p ~ N O U M 1~ ~ N M M CO ~_ I~ f0 M O 0 M 0 E9 M ti ~ N ti O ~ M ~ s o t ~ i O DD 1fJ ~ U J N ~J H 9 E9 ~ 6 9 ~ ~ ~~ a ~ Q Q ~ ~ ~ ~ ~ ` d O O Q O O O O O O O N 0 M ~ lA ti l!7 M O E9 O O O O O O O O O O i O O O ~y ~ ~, ~ ;a N Y N N O ti M N O Cfl O d' M Q M O CO M O M ~ ~ O OO ~ tf1 M r M ti O N M 0 fD 1~ _ N ~ m J .fl 0 ~ 69 E9 ~ E9 _ 69 y. ti M N ~ r .. Q O C C ~ ~ M V} ~ 69 6 9 ~ ~ 6F? f0 _ -.... ._._. _.. .,..~. -P. ,.-. ..~a. ._ _..~._..._ I ~-- ---~ ~. ...~..~. ..- -. --___... .~..,,. . 0 .~..,. In .._....-_. ....__ ........... O ... .... _.- O _,,,, O ...~.~. ~ ., -. _~..,.,..~_ O _ -,..,_. ~ L O' C O O O O O O N ~ M 0 ti CO 0 69 O O O O O N L O~ ~ O 00 O O 00 M CO O O O ~ O ~ ' N u! f`C U O ~p C N ~ N I ~ M O N M CO r ~ 00 In I~ O O M N M M r lC) 'd' 0 O 0 00 ~ d N -E ~ O O ._ m J .D - N ~ M 69 ~ b9 ~ EA 69 ~ E9 ~ 69 07 69 h ~ ~ r• N !D O ~ Q ~ O a f0 ~ C ~ ~ ~ E/} ~ fA Eg ~ ~ M !I? ~ ~ L ~ N~ ~ O O O M O 0 O 0 M l!') 0 N 0 O 0 E9 O O O O O O 0 O ~ 0 O O O r. ~ ~ N O~ ; N O ~ C ~ O 1~ O (O M CO CO O M ~ O ~ f0 lf) O 00 CC ~ ~ N ~ C N f0 ~ O C C `~ V ( r ti (O M d' ~ CO ~ N 69 N ~ M ~ M! Of (O O d' ti 0 ~ ti M a ` •V f~6 ' ~ 0 69 E9 b9 Ef3 Efl Ef} nj (V `~ _ CA ~~~~ ~, ~ ~ ~ ~ ~- O O O O O o O o M ~n O o f~ d' O 69 O O O o O O o O 0 II ~ ~ O i m 0) O O W N O ~ f0 O M In ~ ~ ~ O N O ~ O ~ ~ O N .4+ O ~ .C ~ N , ~ 1fJ M N f0 ~ N O N 00 O d' M O ` ~ ~' ~ N` .a ~X C . ' ~"~ h M 69 r 69 ~- 69 E9 ~ ! r E9 ( r E9 00 i.9 r r, r f~ N E9 O ~ ~ O M C O O a w ~ ~ ( 69 ~ ~ ~ ~ c co c ~ ~ ~ p o O c Q ~ N o N H V N ~ Q ~ N = O O) ~ O II :~ ~ ~ 0 pIS ~ a ~a o U J c c ~ a~ ~ w ~ y ~ V c • o r ~ o ~ app p ~ °~° °~ V ~ O ~, > o E ~ ~ o ~ Q ~ ~o . v ~ ~ a~ Q, p ~ o ~ m 0 ~ 1 Z a ao c o ~ a~ ~ ~ ~w O cn ~ l~ o. a~ w ~. c ~. cE ~. c ~w .. r O N O) fQ 0 N O 0 v 0 N .n ® a c~ v m~ ~o O~ N Q p -~ N c~ ~~ cn ~~ a~i N d aai3 a~ City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 6-Wastewater Treatment Alternatives Evaluations another major project would likely be required within about 10 to 15 years to upgrade the incinerator(s) again or to switch to an alternate solids management program at that time. If Alternatives RM1b and RM2a are eliminated from the comparison since they do not provide equal reliability to the other alternatives, Alternative RM3 (lime stabilization) has the lowest present worth cost ($33.6 million) and Alternatives RM4 and RM5 (anaerobic digestion) are within 8 percent of the low present worth cost at $35.7 and $36.1 million, respectively. At this level of facilities planning, these three alternatives are considered equal from a monetary perspective since the present worth costs are within about 10 percent of each other. In addition, if a longer time period is used for the present worth analyses, such as 30 years, the anaerobic digestion alternatives are essentially equal on a present worth basis to the incineration alternatives. C. Nonmonetary Considerations Nonmonetary issues should be considered when evaluating alternatives. Such factors include process reliability, future expandability, odor potential, and similar concerns. Table 6.05-2 presents a summary of nonmonetary factors for the residuals management alternatives. Several of the alternatives were rated similarly high, indicating there are no clear-cut best alternatives based on nonmonetary factors alone. Alternatives Nonmonetary Evaluation Factor RM1a RM1b RM2a RM2b RM3 RM4 RM5 RM6 RM7 - - Reliability 0 1 0 +0 5 +1 +1 +1 +0 5 . -- 0 Ease of operation +1 1 +1 +1 +1 +1 +1 +0 5 0 Ability to Produce Class 1 Biosolids +1 0 +1 +1 +1 +0.5 +0.5 +1 +1 Expansion potential 1 1 -0 5 0 5 +1 1 -1 -1 +1 Ease of construction 1 -1 ~ 0.5 ~ 0.5 0 ~ +1 ~ +1 ~ +1 0 ---a__.- __._ _ -_~.. ____,_ ~.~__,.._ m .._.~_~ ---- Potential for Odors ._.... --- +1 -. 0 _ .._-,,, -- +1 - _~__ _ +1 _ ,._____. 1 I - 0 ; ..__~_ ~ 0 ~ - -- _ -0 5 ..._ _.__~. 1 Potential for Dust 11 +1 +1 0 0 1 +1 +1 -0 5 -1 Use of Site/Future Facilities ( +1 +1 +1 +1 +1 0 0 0 +1 Total Nonmonetary score ___...._,,,__ _,_~ ___r ..._~_T.~_.,- ~__- +3.0 ~_,,~.~__. -2.0 w~.____~v __ +3 0 ...__s~~ +3.5 +3 0 ~ n__.rT-____ ~~__~_ ,___._ +3.5 ~.__._~ .. +3 5 ._._~. _. __.....~ +1 0 ( _.._..__i +1.0 _~e _. Note: "+1" indicates the alternative is favorable with respect to a given evaluation factor, "0" indicates a neutral ranking, and "-1" indicates that . the alternative is unfavorable with respect to the factor. Please refer to the discussion in report. Table 6.05-2 Nonmonetary Evaluations of Residuals Management Alternatives D. Environmental and Carbon Footprint Considerations As noted previously, the City of Dubuque has as one of its top priorities to achieve "Green City" designation. While there is no universal definition of "green," there are issues that can be evaluated on a green basis for long-term sustainability, energy usage, and similar concerns. One measure of "green" is the carbon footprint of a given system or process. The carbon footprint is a measure of the amount of Prepared by STRAND ASSOCIATES, INC ® 6-20 RAW:ebt\S:\@SAI\151-200\154\0021Wrd\Report\SB.doc\052708 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 6-Wastewater Treatment Alternatives Evaluations carbon dioxide equivalents given off or produced from a process or activity and is an indication of the impact on green house gas (GHG) emissions (larger carbon footprint =bigger impact on GHG emissions). Table 6.05-3 presents a simplified carbon footprint analysis based on estimated energy demands of the seven residuals management alternatives. The energy usage includes electricity, natural gas, and fuel oil for transportation and incinerator operation. Based on this analysis, the anaerobic digestion alternatives (RM4, RM5, RM6) have smaller energy-related carbon footprints than the other alternatives. E. Recommended Residuals Management Alternative Based on the economic, nonmonetary, and environmental comparisons of the residuals management alternatives, the City of Dubuque selected anaerobic digestion with land application (Alternative RM4). The City may elect to initiate a composting operation in the future (Alternative RM5-Anaerobic Digestion with Composting), though contract land application will be the main disposal option initially. This alternative best meets the City's long-term sustainability and green initiatives and has the following advantages: 1. For the incineration and anaerobic digestion alternatives that are comparable on a reliability basis, the capital costs for all options were very close. 2. The anaerobic digestion alternatives provide the lowest projected annual O&M costs. 3. For comparable alternatives, the 20-year present worth values for the anaerobic digestion alternatives are within approximately 10 percent of the low cost alternative. If a 30-year period is evaluated, the anaerobic digestion alternatives provide the lowest projected present worth costs of any of the alternatives considered. 4. The digestion process will use less energy, including electricity and auxiliary fuel. This will provide a more stable and predictable energy demand over the life of the facilities compared to the other alternatives. Should power and fuel costs continue to increase faster than the overall rate of inflation, anaerobic digestion provides even more economic advantages since it has a lower energy use and produces a reliable source of energy in the form of biogas. 5. The digestion alternatives provide potential for utilizing excess biogas to produce energy, which will further reduce the City of Dubuque's energy use and carbon footprint. 6. The digestion alternatives provide along-term solution, which sets the direction of the Dubuque solids management program for the next 40 or 50 years. With the lower capital cost incineration alternatives, significant upgrades would be anticipated within the next 10 to 15 years, which would likely result in reconsideration of these same issues. Prepared by STRAND ASSOCIATES, INC ® 6-21 RAW:ebt\S:\@SAI\1 51-20 011 54\002\WrdlReport\S6.doc\052708 C R' a •r~~+ a .+ C V C O IC +' 3-' 0 c ~a Q~ ~~ a ~ ~ O ~ o c ~, .n V D M O m W J OD H Z W W Z J N W f~ ~ !~ ~ `~ .~.+ a ~ ~ _ ~ Q C~ O "-' 'O (Q O 7 ~ V C (,I~_ ._ •` ~ V r_ .p ~ C ~ C ~ ~ 'O ~ ~ ~ ~ 7 ~ U C ~•~.LJ- Qooa a V .fl O ~ O +r t y ~ ~ ;~+ 0 ~ Q Q O U . ' '; ' ' N N N ~ M O O OMO N r ~ I~ ~ CO ~ O ~ Ln 'ct ~ GO In ~• N O j II ~ O O ~ O H ~ A ~ o ~ O O O ~ o M N f ~~ ~ ~ e- n r O N O N N O f~ N ~ O O O O N O N N 0 f~ N ~ O O ~ Oa00 O O O ~ f~ ~ 0 O O O ~ CO lD Ln (~ I~ f~ to O 00 N 0 O'; O O r O O O ~ 0 O O! M N< __.~ . _~ . ~ _~•• ._x.._. # ~ O ~ O ~ O ~ M ~ 0~0 O 0~0 ~ 00 O 00 ' ~ :p p `- O r- N N N O O ~ ~ ~ "-' ~ ~ U N N ~ ; 00 d' N € ~ J p O = ~ .V ' CO O _ ` m ~ o ~ B O O o ~n o ~ o 0 0 M O ~ O N ~ N ~ dam' d' N! ~ O O O O ~ ~ .~ •O ~ ~ ~ N M CO M'- t1' ~ r= ~.N:~' 7 ~ U J ~ ?~ ` J _ ; M O 3 d'~ ~I M ~' Q ~ rr O ~ ~~ L Q C O ~ O O O O l(') LS) O O O N ~ O~ O~ V N N M ~ ~ N M N M O ~ O; ; ~ ~ C N (Q ~ _ O N 0 , d' '~' _ _ ~'~mJ fl N Q . C C ~ ' r O ~~ O~ O O O O `O ~ ~ 00 O 00 r L O t~ O ' M d' ~ ~ N 00 N 00 O N O ti ~ :,r C ++ ~ ' ~ ~ r CD ' ~ r r r N O i d' ++ O ~ X C r .•. N 'Q ~ W c . ~ I`c ~ ~ - ~ O I ~ .C ~ ~ c`a ~ ~ ~ ~ ` m \. .~ d " ~ ~ ~ _ m 'C C (Q C C fC to (O ~ ~ ~ Y . III N uI IQ ~ ~, ~ O Q •~ f- ~ a~ Iq ~ _ ~ ~ ~ a~ cn f D O 0 •N N ~ N N rn M i ~ N , ~, ~ -" ca U ~ LL U N O N rn f0 a 0 0 0 v, 0 U C (d +~.. fQ •U O y Q 0 a•°i m a a f. R a d LL C ~I a O r+ C O V C O ad +~ O p ~a ~~ a' °% 3 7 ~ G~ O ~ ~a VD ~ ~ Q i c ~ O ~~~~a ~ ~ C U C UJ= ~ ~ ~ Q Q 'c~ ~ :~ ' ~O 'N ~ ' N r M cfl V rr ~ O C 3c~ o ~ w ~ ~ O c ~ ~ ~ ~S c~p ' .J C ~ Q N ~ ~ Q ~~ Q ! M Q ~ M N ,~ U C C O +~ i0 0 , ~ ~ 'd' ~ ~ N ~ O '.~ ~ ~ ~~ ~ j~ Q Q ~ O U ~ ~ c ~ c ° ~ :a o 'OO ' ° ago er ~ . ,o ~c~ ~~~~ 00 ' .= - O N 3 V (a= fQ p J ) c o !~ 1 _ C a ¢ a C ~ ~ M ~ ~ p ;p ~, M ~ N N ~ ~7 .a ~ ,N r_ V ~ V ' ^ N ~ ~; J ~ ~ . J ` ~ ~ ~ Q Q r N ~ Q C `O ~ O ~ V O N iO ,OG ' Q>t ~ M ~ O C O (0 ~ N ~ r Q C C ;~ N ~ f~ ~ 3 r ~ O ~O! ~ C~ ~ . ~ ~ C ("'C y,, .F+ L i r i ~ M .~; (A N' ~ c ~~ N r Q ~ ~' I ~. N O w 1C 1V N O O O N O N N f~0 a ~ ~ Os M N ~ ~? ~ N pp O : ~ n ~ ,~ U ~ c O - I~ ~ ~ ° r r v a7 ri N N C a II O ; c N ~ N 1- j ' d II .c _ <Q U N (II N (A 'C. U ~ ~ ~ ® o - Ci a°i N s.. O C ~ N E ~ C ~! ~~ O ~ v- O ti- (~O o `~- s O 'V o C C ~ ~ ~ .~; C Q'o O N ~ O ~ ` N ~ ~ '~ > '~ > ~ _ > _ N t[S u~ a N C N C N. ~,N C: .II~ O ~ O ~ Of -p ~ ~~ U U U N M a q City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section f~Wastewater Treatment Alternatives Evaluations In addition, the potential to generate electricity using the biogas is being further investigated and may be included in the final design of the anaerobic digestion facilities. 6.06 OTHER RECOMMENDED PLAN ELEMENTS This Section reviews other recommended plan elements. These recommended improvements are based on a number of criteria, including equipment age and maintenance issues, process reliability issues, and similar concerns. The following elements are discussed: ^ Grit Removal ^ Primary Treatment ^ Final Clarification ^ EfFluent DO and pH Control ^ Peak Flow Management ^ Sampling ^ Emergency Backup Power and Electrical Service ^ Administration Building, Laboratory, and Locker Rooms ^ Vehicle Storage and Maintenance Building ^ Sewer Cleaning Debris Pad ^ Odor Control ^ Other Equipment Replacement ^ Other Maintenance Descriptions of each of these elements are included in the discussion below. Section 7 presents the overall opinion of cost for these improvements, as well as a staging analysis and financial impact summary for the improvements. A. Grit Removal System The existing grit removal system was installed in about 1994 and includes vortex grit removal basins, mechanical grit pumps (replaced in 2007), and grit classifiers. The classifiers are severely corroded and in need of replacement. In addition, the plant has experienced some problems with plugging of the existing grit pumps and discharge piping. The grit classifiers will be replaced with new equipment, which will be reoriented to allow discharge of grit directly to the dumpster below and eliminate the grit conveyor. In addition, an allowance for grit piping revisions is included in the recommended project. B. Primary Treatment The existing primary clarifiers are covered with domes that were installed in the 1960s and were reconditioned in the 1980s. The purpose of the domes was to minimize odor release from the primary clarifiers. In lieu of reconditioning the existing domes, we recommend eliminating the domes and installing weir/launder covers. The tanks would then be open, which would provide better access and fewer concerns with worker safety. The new weir/launder covers would still capture the majority of the Prepared by STRAND ASSOCIATES, INC ® 6-22 RAW:ebt\S:\@SAI\151-200\154\002\WrdlReport\S6.doc\052708 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section C~Wastewater Treatment Alternatives Evaluations odors at the weirs for future treatment if needed. An allowance for dome removal is included in the project budget. A fourth 95-foot primary clarifier would be added to improve primary treatment performance and provide improved redundancy. The new clarifier would be constructed in the space reserved for a fourth primary and would have identical dimensions as the three existing clarifiers. The splitter structure and piping will be modified as needed to accommodate the fourth clarifier. C. Final Clarifier Modifications The final clarifiers were constructed in the 1970s and are currently being refurbished and painted. Stamford baffles were added in the 1990s to improve performance. Additional performance enhancement is recommended by replacing the energy dissipating inlets with a newer style inlet (termed the LA-EDI) designed for shallow final clarification tanks. The large stilling wells would also be replaced with smaller wells, and the inlets would be flanged to the bottom of the inlet well. D. Effluent DO and pH Control The plant will need to meet a new effluent DO limit of 5.0 mg/L, and will also need to meet a higher minimum pH level of 6.5 standard units. To better define the likelihood of meeting both of these limits, the plant should routinely monitor the wastewater DO and pH downstream of the aeration basins to determine how DO and pH change through the remaining facilities. This should be done over the winter (no disinfection) as well as during other times of the years to estimate the impact of the chlorine and bisulfite chemicals. Assuming the effluent will not meet either limit routinely, we recommend the following: 1. Because the HPO system is relatively lightly loaded at the present time, we recommend removing the final stage cover from each HPO train, which will serve to release C02 and raise the effluent pH. Prior to implementing this, we recommend installing a temporary ventilation system to provide air to the last stage rather than oxygen. This will allow testing of the concept prior to full-scale removal of the concrete deck over the last stage. 2. To meet the effluent DO limit, install a cascade aeration system downstream of the dechlorination basin. [Note: Cascade aeration may release adequate C02 to raise the pH and meet the 6.5 limit. This should be investigated prior to the removal of the concrete deck over the last stage HPO basins.] E. Peak Flow Management While the existing final clarifiers have a nominal peak flow capacity of approximately 41.5 mgd based on an overflow rate of 1,200 gpd/ft2, plant staff have indicated that solids loss from these clarifiers is evident at much lower peak flows. This is likely the result of two factors: (1) the plant maintains a relatively deep sludge blanket in the final clarifiers to temporarily store WAS and improve dewatering performance, and (2) the clarifiers are relatively shallow (12-foot SWD). This plan includes measures to Prepared by STRAND ASSOCIATES, INC ® 6-23 RAW:ebt1S:\@SAI1151-200\1541002\Wrd\Report\S6.doc\052708 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section fi-Wastewater Treatment Alternatives Evaluations address both of those concerns. However, extended peak flows could still be problematic for the plant, so we recommend implementing off-line equalization of peak flow events by converting the two existing trickling filter structures to equalization basins. These structures were built in the late 1960s and were evaluated in early 2007 for conversion to equalization basins. That report developed a conceptual plan for the conversion but indicated that the wall-to-slab construction joint will need to be evaluated to determine if it is water-tight. If not, this joint will require some work to provide a watertight joint. The structural design of the basins was reported to be adequate to store wastewater, and the hydraulics into and out of the structures are well-suited for service as equalization basins. Wastewater would first flow through the influent screens, grit removal tanks, and primary clarifiers. A diversion structure would divert flows above an operator-adjustable maximum flow rate (e.g., flows > 20 mgd) to the equalization basins for storage, and all flows up to the maximum flow rate would continue to the HPO basins. As flows decrease below the maximum flow rate, wastewater will be pumped from the equalization basins to the forward flow. Detailed hydraulic analyses may result in gravity flow from the equalization basins to the downstream HPO basins to reduce the amount of equalized flow pumping. If peak flows were sustained long enough to fill both equalization basins, these basins would overFlow to the HPO basins. The HPO basins will be modified to allow operation in the contact stabilization mode during extended peak flow events. During such events, this mode of operation reduces the solids loading to the final clarifiers and increases RAS inventory in the converted HPO basins. This modification requires the addition of splitter structures and repiping of RAS and forward flow streams. Refer to Section 5 for additional discussion. F. Sampling The existing influent and efFluent samplers are suspected of collecting unrepresentative wastewater samples as noted previously. We have included two new influent samplers to replace the two existing samplers, and these will be located in the existing gaseous chlorine storage room. A new efFluent sampler will also be provided and will either be located in this same room or a new dedicated sampling building (pre-engineered FRP building) will be included near the existing chlorine contact tank. G. Emergency Backup Power and Electrical Service The plant currently has two electric utility power feeds for redundancy, which has provided adequate and reliable electrical service for many years. However, the City is planning to install backup generators at the remaining lift stations that currently do not have backup generation. This will result in continued wastewater pumping to the WPCP even when a widespread power outage occurs. In this case, assuming both feeds are lost, wastewater would continue to flow through the plant, but none of the treatment equipment would have power to operate and only limited treatment would be provided. The plant currently has two electrical services, and we have included two generators (estimated at 600 to 800 kW each) to provide backup power to each service with automatic switchgear. As part of the Prepared by STRAND ASSOCIATES, INC.® 6-24 RAW:ebt1S:\@SAI1151-200\154\002\WrdlReport\S6.doc\052708 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section C~Wastewater Treatment Alternatives Evaluations detailed design, an evaluation will be made to determine if the WPCP should convert to a single electrical service, which would require only one backup generator and would reduce the monthly service fees from the electric utility. In addition to backup generation and the plant's electrical service, some of the electrical distribution gear within the plant is more than 30 years old and should be replaced. Also, the motor control center in the headworks building should be relocated or the building modified to eliminate the doorway between the electrical room and the screening and grit handling spaces. We have included electrical allowances for these modifications. H. Administration Building, Laboratory, and Locker Rooms A detailed space needs study will be provided during the design phase of the project. For the purposes of this report, we have included an allowance of approximately $125/ft2 for renovation of the existing administration building, including the office spaces, employee spaces, laboratory, and locker rooms, as well as the locker room and employee spaces in the existing solids processing building. These buildings were constructed in the late 1960s with some additions and modifications in the 1970s. The allowance includes improvements to energy efficiency, updating the finishes and furnishings, and bringing the building up to ADA standards. A laboratory addition is also recommended, and an allowance of $300/ft2 was included for additional laboratory space of approximately 700 ft2, plus a basement extension under the laboratory at $150/ft2. Vehicle Storage and Maintenance Building A new vehicular storage and maintenance garage is desired to address the limited storage space currently available. An allowance of $150/ft2 is included for a structure that is approximately 80 feet by 60 feet (about 4,800 ft2), which would provide three open bays plus some additional storage space. A more detailed evaluation of space needs will be included during the design phase of the project. J. Sewer Cleaning Debris Pad Currently, sewer cleaning crews use the WPCP site to store sewer cleaning/jetting debris. To improve dewatering and handling of such material, a drained concrete pad is included in the project budget. We have assumed that this pad will be located near the existing ash lagoons and will be drained back to the plant drain system. K. Odor Control We have not included new odor control systems for the WPCP since odors from the renovated plant are not anticipated to be significantly different than from the current plant. However, the design will incorporate the ability to easily and readily add odor control for the existing primary clarifiers, headworks building, and sludge dewatering areas. Prepared by STRAND ASSOCIATES, INC ® 6-25 RAW :ebt1S:\@SAI\151-200\154\002\Wrd\ReportlSB.doc\052708 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 6-Wastewater Treatment Alternatives Evaluations L. Other Equipment Replacement Numerous pumps, compressors, gates, and related equipment throughout the plant are either very old and operating beyond their normal useful life or are known to require replacement. We have included a listing of this equipment below and have budgeted for the replacement of such equipment in Section 7: 1. Influent magnetic flow meters (two) 2. Primary clarifier drives 3. Primary scum pumps (three) 4. Primary sludge transfer pumps (three) 5. RAS pump VFD replacement (six) 6. WAS pumps 7. In-plant waste/recycle pumps (three) 8. Plant effluent/process water pump (one) 9. HVAC systems (inspection and allowance included) M. Miscellaneous Piping, Valves. Gates. Mechanical, and Other Components Much of the interior and underground piping infrastructure at the plant was installed in the late 1960s and mid-1970s, so it is more than 30 years old. Much of the original exposed piping is in poor condition, and many valves are inoperable. The condition of the underground piping that is still in use has not been determined. Plant personnel have indicated that most of the gates are difficult to operate and should be replaced. The following list includes components that are known to require replacement or are recommended for improving operations at the plant: 1. Influent channel gates. 2. Primary clarifier splitter gates. 3. MLSS splitter gates. 4. Final clarifier influent splitter gates. 5. Rerouting in-plant waste/recycle pump discharge upstream of the influent screens. 6. New septage/hauled waste receiving station. 7. New roofs on existing buildings. In addition to these components, other valves and piping will require replacement. We have included an allowance in the overall project cost to account for a significant amount of mechanical piping and valve replacement. Prepared by STRAND ASSOCIATES, INC.® 6-26 RAW:ebt1S:\@SAI\151-200\154\0021Wrd1ReportlS6.doc\052708 SECTION 7 RECOMMENDED PLAN AND FISCAL IMPACT ANALYSES City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 7-Recommended Plan and Fiscal Impact Analyses Previous sections of this report presented background information, described and evaluated the Dubuque WPCP, projected flows and loadings, and reviewed alternatives necessary to meet the projected needs at the WPCP. This section presents a summary of the proposed modifications to the Dubuque WPCP, the proposed staging for these improvements, an overall cost summary and preliminary financing plan for the proposed improvements, and the fiscal impact of the recommended plan on the City of Dubuque's wastewater-related user rates. 7.01 RECOMMENDED PLAN SUMMARY The recommended plan includes improvements to nearly all portions of the existing Dubuque WPCP. The City has elected to construct all the recommended facilities in a single construction project. Figure 7.01-1 presents the preliminary site plan for the recommended improvements, and Table 7.01-1 presents a summary of preliminary design conditions for the recommended plan. A brief summary of the recommended improvements is included below: A. Influent Screening 1. Replace the existing screens with 1/4-inch fine screens (consider 1/8-inch screens). 2. Install screenings washer/compactors. B. Grit Removal 1. Replace the existing grit classifiers. 2. Eliminate the need for dewatered grit conveying by reorienting the grit classifiers. 3. Reconfigure grit pump discharge piping. C. Primary Treatment 1. Remove domed covers and replace with weir covers only. 2. Construct fourth primary clarifier. D. Biological Treatment 1. Continue with HPO activated sludge, including hauling liquid oxygen to the plant. 2. Replace aeration mixers (27). 3. Replace HPO controls for all three trains. 4. Inspect concrete basins. 5. Seal concrete deck. E. Final Clarification 1. Install new energy dissipating inlets. Prepared by STRAND ASSOCIATES, INC ® 7-1 RAW:ebt1S:\@SAI\151-200\154\0021W rdlReportlS7.doc\052108 Anaerobic Digesters and Control Building 1 ` s~ ~ , f~ ~ ~ -!~lre0ri~e Maintenance ~ . Building ~ ~ ~ I , ` Renovation ~ . ~ and Lab Addition I In-Plant Waste Pump Station Peak Flow Notes 2 and 3 Equalization MLSS Splilter ~ Structure Tank Activated Sludge Train C Solids Handling ' Bldg Activated Note 1 Sludge Train B I Grit WAS ^ WAS Basins Pumps Activated g Stud e STanke Peak Flow Liquid Oz Trai nA I Storage Equalization Tank screening New Primary CI iffier Bldg ~ Remove Dechlorination I and Weir Covers Equipment; Upgrade (Remove Domes) LOX Controls . ~ - - - ^ New Aeration New Screens, Grit Classifiers, Diffusers and WAS Storage Aeration Blowers; Remove Chlorine Equipment New Influent Flow Meters and Samplers Notes: 1. Remove incinerators and appurtenances; install WAS thickening and biosolids dewatering equipment; renovate locker room; demo old equipment; convert a portion of the N building for temporary cake storage and loadout. NO SCALE 2. Inspect basin interiors, seal concrete deck; new monitoring equipment; replace mixers (27). 3. Reconfigure to allow contact stabilization mode for extended peak flows. ,. ~ ' __ - ' 1 . _ ~ . ~ ' Remove Ash Ponds and • RAS Pump Dewatering Pad I Station Ash Pad ' o O Asli Pond I Final Final ~ ~larifer Clarifier ~ Ash Pond I UV Tank • al Final CI rifer Clarifier ~' New Energy New Cascade Aerator ' Dissipating Inlets ~ ^ Convert Chlorine Contact Tank to UV Tank Legend -Existing - Existing with Upgrades - New Structure Refer to text for additional construction not shown. Q J W H fn Z W W 0 f~ D W Z W V W Q J 4 H W Jd3 ~m0 w O ~ O m 3F~ W~G m D FIGURE 7.01.1 1.154.002 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 7-Recommended Plan and Fiscal Impact Analyses TABLE 7.01-1 UNIT PROCESS TREATMENT -PRELIMINARY DESIGN CRITERIA Design Parameter Value Design Year 2030 Flows and Loading Average Dry Weather Flow 9.14 Average Annual Flow (mgd) 10.64 Average Wet Weather Flow (mgd) 13.47 Maximum Month Flow (mgd) 13.13 Maximum Week Flow (mgd) 15.83 Maximum Day Flow (mgd) 24.50 Maximum Hourly Flow (mgd) 40.86 Average BOD (Ibs/day) 36,900 Maximum Month BOD (Ibs/day) 41,200 Average TSS (Ibs/day) 29,400 Maximum Monthly TSS (Ibs/day) 37,100 Mechanically Cleaned Bar Screens (Replacement No. of Units 2 Size and Openings 3-ft 6-in width, 1/4-in opening size Type Step or perforated plate Capacity 20.0 mgd (each unit) Grit Removal (Existing basins, Replacement Classifiers) Number of Units 2 Type Vortex Capacity 34 mgd, each Primary Clarifiers (1 New No. of Units 4 Type Circular Diameter, ft 90 Side Water Depth, ft 9 Total area, ft~ 25,450 OverFlow Rate, gpd/ft2 @ 10.64 mgd 420 @ 40.86 mgd 1,600 Anticipated BOD/TSS Removal, percent 25/68 High-purity Oxvaen Activated-Sludge Tanks (existin Number of Trains 3 Number of Tanks/Train 3 Tank Length, ft 90 Tank Width, ft 26 Prepared by Strand Associates, Inc.® Page 1 of 4 TMS:pII\S:\@SAI\151-200\154\0021Wrd\Report\Table 7.01-1.doc\052208 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 7-Recommended Plan and Fiscal Impact Analyses Design Parameter Value Side Water Depth, ft 12 Volume, ft3 (total) 252,720 Design Avg. BOD Load, Ib/1,000 ft3/day 122 Design HRT @ 10.64 mgd, hrs 4.3 No. of Mixers (Replacement) 27 Mixer Horsepower (each train), hp Tank 1 30/15/10 Tank 2 10/7.5/7.5 Tank 3 5/5/5 Oxygen Storage (existinq) Liquid Storage Capacity, tons 44 Vaporization Capacity, tons/day 22.8 Final Clarifiers (existin No. of Units 4 Diameter, ft 105 Side Water Depth, ft 12 Surface Area, ft2 (total) 34,640 Volume, ft3 Each 103,920 Total 415,680 Overflow Rate, gpd/ftz @ 10.64 mgd 307 @ 40.86 mgd 1,180 Weir Length, ft Each 312 Total 1,248 Weir Loading Rate, gpd/ft @ 13.47 mgd (avg. wet weather) 10,800 Effluent Disinfection (New: Reuse Existing Contact Tank Type UV light; high-pressure, medium intensity Number 2 Design Flow, mgd 40.86 Installation In existing Chlorine Contact Tank Peak Flow Eaualization (Converted Trickling Filters) No. of Units 2 Diameter, feet 195 Total Volume, gal 3,000,000 Aerated WAS Storage No. of Tanks 1 Dimensions 55 ft x 80 ft x 14.25 ft SWD Volume, gallons 469,000 Max. Month WAS, Ibs/day (Yield = 0.6 Ibs/Ib) 18,540 Prepared by Strand Associates, Inc ® Page 2 of 4 TMS:pII\S:\@SAI\151-200\154\002\Wrd\Report\Table 7.01-1.doc\052208 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 7-Recommended Plan and Fiscal Impact Analyses Design Parameter Max. Month WAS, gpd Storage, days (1.9 percent TS @ max. month) WAS Thickening Equipment (Newt No. of Units Max. Month Thickened WAS, gpd Operating hrs/week Hydraulic Loading, gpm (@ max. month) Solids Loading, Ibs/hr (@ max. month) Thickened WAS, percent solids Blended Sludge Holding Tanks (existin Previous Use No. of Tanks Total volume, gallons Storage, days (@ max. month) Anaerobic Digestion (New No. of Tanks Dimensions Diameter, ft Maximum SWD, ft Volume, gallons (each) Volume, gallons (total) Max. Month Blended Feed Sludge Volume, gpd Total Mass, Ibs/day Volatile Solids Load, Ibs/day (85% volatile) Detention Time, days (total) Thermo @ Max. Month Overall @ Max. Month Volatile Solids Loading, Ibs/1,000 ft3/day Thermo @ Max. Month Overall @ Max. Month Biosolids Dewatering (2 Newj No. of Units Type Max. Month Biosolids Feed to Centrifuges Volume, gpd Mass, Ibs/day Operating hrs/week Hydraulic Loading, gpm (@ max. month) Solids Loading, Ibs/hr (@ max. month) Expected Cake Solids, percent Value 117,000 4.0 2 or 3 49,400 32 430 4,060 4.5 to 6.0 Primary sludge storage 2 293,000 2.8 4 (2 thermo, 2 meso) 70 27.5 791,600 3,166,500 104,400 43,770 37,200 15 30 175 88 3 (2 new, 1 existing) Centrifuges 104,400 23,300 32 380 5,100 27 Prepared by Strand Associates, Inc ® Page 3 of 4 TMS:pII\S:\@SAI\151-200\154\0021Wrd1Report\Table 7.01-1.doc1052208 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 7-Recommended Plan and Fiscal Impact Analyses Design Parameter Biosolids Storage (New, Converted Bldg) Biosolids Cake @ Max. Month Conditions, ft3/day Storage Capacity, days Volume Required, ft3 Stacking Height, ft Min. Area, ft2 Actual Area, ft2 (w/operating room) Value 1,330 14 18,600 6 3,100 4,000 Prepared by Strand Associates, Inc.® Page 4 of 4 TMS:pII\S:\@SAI\151-200\154\0021Wrd\Report\Table 7.01-1.doc\052208 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 7-Recommended Plan and Fiscal Impact Analyses F. Effluent Disinfection 1. Replace chlorination and dechlorination with ultraviolet light disinfection. 2. Reuse contact tank for UV installation. G. Effluent DO and pH Control 1. Routinely monitor the wastewater DO and pH downstream of the aeration basins to determine how DO and pH change through the remaining basins. Based on this monitoring: a. Install a cascade aeration system downstream of the dechlorination basin. This will serve to increase DO and also release C02 to raise the effluent pH. b. If needed, remove the final stage concrete deck from each HPO train, which will serve to release C02 and raise the effluent pH. H. Peak Flow Management 1. Convert trickling filter structures to off-line flow equalization downstream of primary clarification. 2. Modify HPO basins to all operation in contact stabilization mode of activated sludge. I. Sampling and Flow Metering 1. Provide two new influent samplers. 2. Provide new effluent sampler and sampling enclosure near the chlorine contact tank. J. Residuals Management 1. Decommission the fluid bed incinerators. 2. Construct new anaerobic digestion facilities (TPAD). 3. Install new WAS thickening equipment in the existing incinerator building. 4. Rehabilitate the WAS storage tanks and provide new WAS storage aeration equipment. 5. Provide two new dewatering centrifuges; remove one existing centrifuge (use for parts) and belt filter press. 6. Convert existing incinerator building to biosolids cake storage and load-out facilities. 7. Consider electrical generation for biogas. Prepared by STRAND ASSOCIATES, INC ® 7-2 RAW:ebt\S:\@SAI\151-200\154\002\Wrd\ReportlS7.doc\052108 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 7-Recommended Plan and Fiscal Impact Analyses 8. Establish contract with biosolids contractor to provide hauling, off-site storage, and land application biosolids. K. Emergency Backup Power and Electrical Service 1. Install new emergency power generation equipment. 2. Consider two smaller generators since there are two electrical services at the plant. 3. Consider consolidating biogas electrical generation and backup power generation equipment. 4. Replace electrical switchgear and distribution equipment from the 1970s and before. L. Administration Building. Laboratory, and Locker Rooms 1. Conduct detailed space needs study. 2. Refurbish the existing administration building. 3. Refurbish locker rooms in the administration building and the incinerator building. 4. Expand the laboratory portion of the building by approximately 700 ft2. M. Vehicle Storage and Maintenance Building 1. Construct new facility for vehicular storage and maintenance (approximately 4,800-ft2). N. Sewer Cleaning Debris Pad 1. Construct new receiving station for sewer cleaning debris to allow dewatering and storage for this material. 2. Consider incorporating a hauled waste receiving station into this facility. O. Odor Control 1. Provide ability to install odor control for the headworks and primary clarifiers in the future. P. Other Equipment Replacement 1. Influent magnetic flow meters (2), effluent flow meter, and excess flow meter. 2. Primary clarifier drives. 3. Primary scum pumps. ~' 4. Primary sludge transfer pumps. 5. RAS pump VFD replacement. 6. WAS pumps. Prepared by STRAND ASSOCIATES, INC.® 7-3 RAW:ebt\S:\@SAI\151-200\154\002\W rd\ReportlS7.doc\052108 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 7-Recommended Plan and Fiscal Impact Analyses 7. In-plant waste/recycle pumps. 8. Plant effluent/process water pump. 9. HVAC systems. Q. Miscellaneous Piping. Valves. Mechanical and Other Components 1. Influent channel gates. 2. Primary clarifier splitter gates. 3. MLSS splitter gates. 4. Final clarifier influent splitter gates. 5. Reroute in-plant waste/recycle pump discharge upstream of the influent screens. 6. New septage/hauled waste receiving station. 7. New roofs on existing buildings. 7.02 OPINION OF CAPITAL COSTS AND PROJECT FINANCING The opinion of capital costs for the recommended improvements is approximately $48 million (December 2007 costs basis). Projecting this amount to an anticipated fall 2009 bid date, and applying a construction inflation rate of 4 percent annually, the anticipated total project costs are approximately $52.2 million. Table 7.02-1 presents a summary of the opinion of capital costs. The WPCP improvements are anticipated to be financed entirely through Iowa's State Revolving Fund (SRF) loan program. The SRF program provides 0 percent interest financing for up to three years for planning and design services. These loans can be rolled into the SRF construction loan. Construction loans are offered at 3 percent interest, typically for 20 years although terms of up to 30 years can be accommodated. In addition to the 3 percent loan interest, an administrative fee of 0.25 percent is added each year to the outstanding principal balance for administering the loan. Also, an additional 1 percent of the loan amount is included as a loan initiation fee. Assuming a total loan amount of $52.2 million, plus the initiation fee of $522,000, the annual debt service payment is expected to be approximately $3.6 million. If cogeneration equipment (generator set, heat recovery, gas conditioning) is included in the project, the anticipated loan would be increased by approximately $1.5 to $2.0 million, and the annual debt service would increase to approximately $3.8 million. 7.03 OPINION OF OPERATION, MAINTENANCE, AND REPLACEMENT COSTS The recommended plan will have an impact on the overall operating budget for the Dubuque WPCP. Table 7.03-1 presents the proposed operating budget for fiscal year 2013 (July 2012-June 2013), which is the first full year of operation of the facilities in the recommended plan. This table presents only the key changes between the proposed 2006/2007 budget and the projected 2012/2013 budget. The remaining budget elements are anticipated to remain the same but are adjusted for inflation at an assumed inflation rate of 2.5 percent annually. Key changes in the proposed budget include a minor Prepared by STRAND ASSOCIATES, INC.® 7-4 RAW:ebt\S:\@SAI1151-200\1541002\Wrd\Report\S7.doc1052108 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 7-Recommended Plan and Fiscal Impact Analyses TABLE 7.02-1 OPINION OF CAPITAL COSTS Project Component ~ Opinion of Capital Cost _ r Influent Screening _ ~. r.=- - --~ ~_ Equipment and,Channel Modificatlons_ _.__~_ ~ut«m.~_...,_..~~.w_.,..__ .__~~,... ~«~.~.___~~..~ _, _._.x~ __.._ __,Nx $510,000_ _. Grit Removal __ Grit Classifiers and Conveyor Modifications _~ ~»._~t ~ -- - _ ~~_ r . $105,000 _ _ ~nn_, W _ vPrimar~r Treatment Dome Removal and New Covers . _ 4th Primary Clarifier (equipment and structure) , _ _ _.~ -- m -- -~ ~ --- -~-- --- _..~ ~ _ ._- - ~ - HPO Activated Sludge _____ f ___ New Mixers, Drives, and Motors ~ ~ $203,000 ~ _ ~ $1,200,000 _ -~- ~ _T.r _~_ $1,438,000 _ New Controls ~ _~~_.._ .n_~_r_~.w.___.~._~ ~ ._~~_r~ ~~_~ LL _ W y ;_ __ _ $547,000 4° Concrete Deck Restoration $350,000 ~.~ - Final Clarifiers r~ -~ New LA EDI and Stllhng Wells $227,000 ._,_. _ .__ W,__e___.__._.~.___~_.__ ._ .__ ~__-_., _r.._,._.____ r________._...._ _ _.....,. Disinfection UV Equipment and Tank Modifications DO and pH Llmlts _ - ~ _.__Cascade Aeration ___ _. --- ~_ ~_ __I %_y Monitonng_Equipment _ ~ __.__.r_~.____,__..__ __.____r_. __,____. $901,000 s -~ ~K __,___ __,__a ,$70,000„ - -- _ _ _ _ _ _ _ _ _ _ $25,000 u_~~ -~ Peak Flow Management ._ Equalization Tank and Splatter Structure Modifications --- $500,000 Contact Stabilization Modifications ,r= u ___~...~ ___._ mwm a~~ _, __ _ ~.. $200,000 _ _____a~._m~r_. -- - _ _ ___ _.__ -__ ._ ~_ , Residuals Management . Stabilization System . __ __ .mW___,.___._.._.. , , _._ .~ _. _ _. __ Dewatering, Thickening, and`Conveying Equipment and Storage ._ ~__ _ _~____..._~.__m~ r_w _ _ $8,939,000_ ._,., _ --_____ $2,192,000 WAS Storage Aeration_Equipment_Y_ $318,000 !, Building Modifications (Allowances __ N___~ _~ r__ y~tl __ __Y_.y ._ ~ _.._ _ _.__ _ Sampling .~_._ __.._ .~_._ _ ._, .. -- Influent Samplers _ ~ ~.~ ..w __ _ _ ~. EfFluent Samplers and FRP Bldg ~ _ $500,000 P_._n _... _».~.._~ _ .____ ____ _~___ _ ~._ $18,000 ~_ $25,000 Prepared by Strand Associates, Inc.® Page 1 of 2 TMS:pII\S:\@SAI\151-200\1541002\WrdlReport\Table 7.02-1.doc\052708 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 7-Recommended Plan and Fiscal Impact Analyses _Emergency Backup Power - s{ry~v33f@-~~ Generators ~- __._.-_.m_._~,-_n._.~ ~__az_.- ~ ..~ Tt_=--- -- -~--~__- ~ _ - ~---_ ~ _~~~__ _$480,000 '. ~- -- _ - ~ ~_ _ -- _-- ~ - --~ --a-- -- = - Miscellaneous Equipment Replacement .-____44__~__-_-ny -,_ ___4 $ 770,000 - m . ~ -- - - x ~ r - - r Subtotal_Egwpment-and Structures_____ v.._v__.-~_~_._e.____~~_, __ __ ~m~__ _ -_-- , - ~-.. ~__ .~~ ~~~ ~__.~,____~~e~.~_.e-_~_ _.___...~.__________.__.,_. Undefined Subcontract Work ~._ ,_.- .. __._~- ._~__..__~__.____.~_...__.__~ _~_.~__~_.~~__.. _..._~ .____~____r_ r.. __. ____w__~.__._ Site Work ______-_~__a_~ u--_~--- --_-~..._~.-------~ ---- -------~----------__.~~__._-___ ____...~ HVAC __~~_~_~-_.~_ ~._~. ~- - ------_ ~_. ~._._ ~ __...._ _w___._~.M.__- __-__ .-____~M ___ _.._~ _~.~_.~_.e Mechanical Electrical ,________m_.n-~ __~r __,_$19,518,000 _ _____,~.___~.__-_~.-__.,.~~ .._ -._ _ ._~_______a_.._~__...___~~ _~_.~_~ ~__e~ __ _ $976,000 ._._~----------___._~--~-___. __._~._ $1,366,000 . __ __ ._..~_~._ . _ ... __....__.u ... -_. ~.~, $3,904,000 ,' $3,904,000 :Allowances ~= -- - -~- ---- - ~~4 Mlscellaneous Demolition ~- _. 250,000 Mlscellaneous Pipin~g,uValvesixand_Mechanical Components_~ ~_ $500,000 ~ ~ ~==T~mm V Electrical Service .~~~~-,~ _--_.,,,.,,.__~--__t_ ~~rm,_r. r._wmmv.~ -------- -__ -~ ~-~ - - - $200,000 ~ _ __ - ~ - ;eT_ MCC Replacement _ __ ~ _ Admin Bldg Refurbishment (80'x35'x2 floors)z__ __ a _ Y y _ ~ .._~~a. - Admin Bldg Lab Addition (35X20x2 floors ~ _____,___ __s___ _ y_. _Solids Processing Bldg_Locker Room Refurbishment _ ___._ _..- ~.-- --.__._ ,..___ __ ___~_ y__ _ Vehicle Storage .and Malntena_nce Building (3 bay, 80'x60') _ Sewer Cleaning Debris Pad ~ _. ___ - Septage Receiving Station _a _~ _ __ _u, _.z _ ~- - _ $500,000 r __ _ $700,000 .- - -- $315,000 $100,000 - __-~_ _. ~ __z__ _~~~ _ _ , _ _ _ K _ $720,000 _ -$50,000_ $75,OOQ F ~_- Subtotal $33,078,000 = Contractors General Conditions. _....~.r._ w..~..._.. ~___~_-_V _.._.rc~_..w._~___~ -- z .__.r~~F- .-__-__... ,,, __~__~~~2,646,000 _ .. ..~. ~._, r.-,_ -_ ..- ~~ y~ °e_ ~ ._ ~ .. __ ~ ... _ - - - --. ~ .Subtotal _ ~ _ _ _ _ _ a~ - , -- Technical Services and Contingencies - v._ ~____ __ _~_ .. _ _ . ~ _ x__~. _. $35,724,000 !; _ $12,503,000 TOTAL OPINION OF CAPITAL COSTS (December 2007 227 Prepared by Strand Associates, Inc ® Page 2 of 2 TMS:pII\S:1@SAI\151-200\154\0021Wrd\Report\Table 7.02-1.doc\052708 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 7-Recommended Plan and Fiscal Impact Analyses TABLE 7.03-1 OPINION OF ANNUAL O&M COSTS -POST CONSTRUCTION 2012-2013 O&M Budget Category 2006-2007 O&M Budget with Project and Inflation - -- - _ ~ Wa es _.W.m__~g__ -_- , --_..__. d _ -_.___ _ .___~__h.~ ~__. -.a__a _ ._ $ 943,838 _~. _.~_ _. -. _ - ~ -...._ __...___.__ _ __ ...__ $ 1,015,000 __~~.~__~_m_ ~.v_..~ .. . _. Retirement Benefits 126,206 135,000 I Health Benefits ~ 221,873 238,000 Other Employee Expenses __._ ~ -~~ -~ _ ----_4,649= . ______-_. _. r ~ ~_._..,_ _ _.M___~___~~~ =~~z~._ 5,000 -- - - -_ - Supplies and Services ----- - 10,081 ~ - - - ~ 12,000 ~-- . a -- -- FPrinting and Publishing.._-.__. _~.__~ ..~ ~_. -v- ~- - .__- .-. --~~__- __ ~_ ---1,585 _a_~_~n _ r_ n ~. ___ ~~,__._ ~_ ._._~. ____ 2,000 ~-~~~ - LL _~_~_ Insurance Taxes and Damage 195,213 226,000 Travel Related Costs 10,875 13,000 Utilities and Property Maintenance ~_ 399,520 ~._~ 389,000 Electricity 84,200 69,000 ' Natural Gas ~ 71,495 _ _ 83,000 Other a~ - -- -- 15,851 _- 18,000 _ ~,. - - Maintenance and Operating _ _.~._ ._ _~ ..~,.. _ ___ ~ _ ~ _ _ ~ i ~ ...._ _.- _._ . _, .._..__.,._. _ M_~. ~...___ _u_ ~ ~ _-~ _ ~- - -~__~a_~ ~ _.~--,. _......... Li uid 02 ____~ ~~. q - _ _ 323,802 _._ __. .____..___ .- .__~ 406,000 e _ ~ ...- _ -, Incinerator Fuel -- ~ -- m_ . ~ _ ___- - ~ ~ --- - - 248,920 ---- ~ --p ---- _ .. ~ __. _ Other 494,741 574,000 Contractual Services _- - -n ___ ma T _ _ Existing ___._ _ 82,896 96,000 New Residuals ~ ra_ ~ _ - -~ - ~_~. --TDisposal ..._._ . ...r..,,, ...._~ _=z __.~~~ _?,718 _ _ .r_~~r,-= _,__„_=.328,000. _ _...._ ~ - ---- Overhead/Stores/Garage 61,000 ~ 3,000 Vehicles r-..~_.~._ _._.._.47,369 __ _ ___. ' _ -- -- 71,000 ' Tools/Construction Equipment 2,200 55,000 . _ -. _ Other Equipment _ . 500 - 3,000 ..Safety Equipment _. ___ __. _ _ ~ 82,896_._....__._ ~ .1,000 .._..... __--__-u _- .-__- ~ _----~._-- -_-.~._ ~._ _ . Total Expense Budget _ _ I ..-_ ____~_ ,_u.__N_ ~sae__.__N _..____._ _ $ 3,349,532 ~ ._ ~._..- _~--.-- ~.-____. __. _~__a ___,e_a_..__ $ 3,742,000 Prepared by Strand Associates, Inc ® Page 1 of 1 TMS:pII\S:\@SAI\151-200\1541002\WrdlReportlTable 7.03-1.doc\052708 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Section 7-Recommended Plan and Fiscal Impact Analyses reduction in overall staffing and fringe benefits through anticipated attrition (although with inflation adjustment labor and benefits costs are still projected to be higher), a reduction in the amount of energy and fuel required for biosolids stabilization, and an increase in the costs for biosolids disposal. For fiscal year 2013, the projected annual O&M budget is approximately $3.7 million. If cogeneration equipment is included in the project, the annual O&M cost for the WPCP would decrease since the cogeneration facilities would provide electricity to be used at the plant. The annual electricity savings could be in the range of $150,000 to $200,000 less O&M costs associated with the cogeneration system. An equipment replacement fund, while not a requirement of the SRF loan program, could be initiated by the City to provide funds for future equipment replacement. Payments to this fund would be made annually from sewer fees, and these funds would then be used in the future as needed. Preliminary payment ranges to such a fund are in the range of $300,000 to $500,000 annually. However, the existing WPCP budget has significant funding already included for equipment maintenance and replacement, and some of those currently budgeted items would offset the payments noted above. The actual amount budgeted for equipment replacement will be determined by the City on an annual basis. 7.04 SEWER USE RATE IMPACT OF RECOMMENDED PLAN The current fiscal sewer use rates for the City of Dubuque are $2.26 per 100 ft3 of water used. For a typical residential connection using 800 ft3/month, the current monthly sewer bill is approximately $18/month. Based on the City's preliminary sewer rate analyses, implementation of the recommended plan is expected to increase average sewer use rates by 50 to 55 percent above current rates to approximately $28/month. 7.05 PROJECT IMPLEMENTATION SCHEDULE The preliminary project implementation schedule is included below and assumes a single construction project. In addition, the schedule assumes an approximate two-month review and approval duration by the IDNR for the facilities plan and future design documents. Facilities Plan Submittal to DNR Public Hearing DNR Approval Begin Design Submit Design Documents to DNR Construction Bid Date Construction Completion June 2008 July 2008 August 2008 August 2008 Summer 2009 Fall 2009 December 2012 Prepared by STRAND ASSOCIATES, INC ® 7-5 RAW:ebt\S:\@SAI\151-200\15410021Wrd1Report\S7.doc\052108 J APPENDIX A CITY OF DUBUQUE WPCP NPDES PERMIT . IOWA DEPARTMENT OF NATURAL RESOURCES National Pollutant Discharge Elimination System (I®l~t 6 ... ~ ... , ......,! ~-- - - ~a .v, P~'M'~ IDSNlI'PY AND LOCATION OF FACZLIY4 `V Q CITY OF DUBUQUE CITY CLERR CITY HALL DUBUQUE, IA 52001 IOW]- SI.+DFS vr~:r*'n HOlIDSR: 3126001 DA'!B 08 ISSO7IHCS: 07-14-1998 DAT'S OF BBpIRATIONS 07-14-2003 YOO ARS RHQOIRED T'O F17.8 FOR B8~1L OF TB=I9 PBBMIT HY: 01-15-2003 BPA N01m81ts IA0044458 DUBUQUE CITY OF STP Section 6, T 88N, R 3E DUBUQUE County, Iowa MISSIS6IPPI RIVIfft BOOTS OF FLOW Return Receipt Requested This permit is issued pursuant to the authority of section 402(b) of the Clean Water Act (33 U.S.C 1342(b)), Iowa Code section 4558.174, and rule 567-64.3, Iowa Administrative Code. You are autho- riaed to operate the disposal system and to discharge the pollutants specified is this permit is accordance with the effluent limitations, monitoring requirements and other terms set forth in this permit. You map appeal any conditions of this permit by filing a,writtea notice of appeal sad request for administrative hearing with the director of this department within 30 days 'of pour receipt of this permit. Any existing, unexpired Iowa operation permit or lows NPDES permit previously issued by the depart- ment for the facility identified above is revoked by the issuance of this Iowa NPDE9 operation per- mit. FOR THS DEPARTMENT OF NATURAL RESOURCES Lary W on. Director By Wayne Farrand, Sup0 visor Wastewater Section ENVIRONMENTAL PROTECTION DIVISION J" Page 1 N m a c o > V M a J ti` M L V . v a b LL m D F- Z W H Q W K F d' W F- a W 3 3 J W J J a J O W ~ > > O W J O O ~ ~ Z O N w Z Z O H O O Q w w F- O u. a a ~ F F- t~il a ~ w IF/l LL N N f- N a~i Q LL J H w J LL V w F- J J w ~ J W ~- J ~ p ILL W Fes- W W ~ W O N W ~ N !~ h t~il OG O 07 ~ N a = N ? N Q Z N C W m L V Q f LL d O 0?C ~ w W W a W q W ~ V F- V Y m d ~ _ ~ M ^ L T d 0~ ~ 0 0 ~ ~ Q t7 m O a ab C O Y r ab r E r C aD 7 4 aD 0a C 3 ~ O J 4 N LL r z r a0 W +' C 3 O V F~-~ 61 ~ ~ ~ w a '~ a o r 3 ~ m r c ~ y r a r W W m ~ o N ab r+ ~W W ~ ~ M v a a a ~ c y LL ~ O ~ U } K ab M = b v H E W M ~ O O a o ~ m n ~- 'o O N O +' r a t _ ~ z° a !. Z J ~ ~ r J ~ •r ~ Ib a ~ o s° Q Q a ti H N Q + + O D O O O ~ ~ F - H C N H y ~ m m J O O z z ~ ° >. •- E . p r r N ~ Ct ~ N ~ ~ O ~ m O O O O ~ ~ o G ~ oQ ~ , a N z 0 0 0 H m o a H G L ~ O ~ N ~ h ~ t 0 M a J ~ F ~ j +~ ~ ` J = J O ~ LL O ~ ~ ~ F ~ W W W y N = = C ~ E O N O r ~ W W N ~ aY O O ~ D m ~ ~ J a J a N G ~ C ~ N V ab y O c m ~ ~ o n an o M4 N Z W Z o v o v o m o ~ o ~ ° a ° ° a L o o a o ° an N ro n> a v a m z z z i a a z z F^ LL LL LL LL LL LL LL LL O J J J J J J J J ~ K K d' d• K ac OC Q: a- a a a a ~ a a a > > > v- > ?• > > > a L ~ m = W +• a J E o o ~ ° ~ a 0. J J ~ ~ OC ~ H y X W V 6 ` ~ m O D ~ i a Z Z ~ M M « a a 0 ~ 1 - LL M M N T O 3 N Z Z O C - F H ~ N J J ~ K LL W W 3 CI D a a O .. F F U 00 ° a v LL F ~ - v a a y L u s t O i t r r L Dm E m 0 Z O L ab L O r C i 9 m M L d O v O a c r T a a 6 L 4• a • E a 41 M H 0 F u G m W m a a LL 0 } F- N V W O m O E m z LL m L r m t t c m r+ a• OLp O U mC7 L C M f Y O mm~ c E >. of O L D r m Y m 'O a~ 'O ma cc y L m m r .- m E E ~ o. .~ L r O L m m m 10 r M L C dm O ~ ~ 3 LV - 'G m M 0W L m O) t m T T m a L s+ 0 3 O>. r O~ V^ u ~~ ~ ~ a v ~ ~ E ~ E C m nr a m E m E L 0 m O U'O m m c aw ~ a m vm o. m c o c •- m L m m m c E y m to L pL ~O r Y L L O m C L >D Ea r y o ~ r m^ ~ C E O 4 . p C M ~. m m C m E va m v r O O ] mMr O d a C r L 7 L ~D o 0 a- m E 3 >. L > m o ++~o a~ ~ ~ > O C V- 7 D L T m C m r ~ ~ ~ r E o V- W m m > ~. 0 0. mc ~° a a m a > LL 4 m m o u E~ o c v a L t r E u ~+ m T x + ~ c m a m ri v ~ ~ ~ r ~~ ~m c~°a u L a m a + + o. ~ m •~ m m'O ~ m~ L~ m o my o ~ r ~ m a t a m m m m m 1pp l 9C O mr E •- C V ~ 'O > L L U Y L > m m ~ a L Lm mL m r E 4 t F-. ^ to r a c « a- m ~ a O O rL Li+E Or~+ v ~ ~ L r E A t E t .C C E n ° m me t . • 'D EoL ~ ~ m w m t7 E m .- m O L O Q~ m ~ O O C 'Oa. m m ~ L O~ t 7'O r C ~. L m O m C 10 m a.m m Lau ~eDv >. t +~ ro m ~ m a •- +• a c m ~ r .. V r ~ N as >~ L yq. O .. D .. U .. 'O .. m .. m r c E L v K C V L O a aoe c E C L 0 Y 0 O O O N_ O t x E • a C r n m O O O J ~/ N M H M .~ 0 F- F F- 1- F F- I- Z Z Z z z v u v u v v o 0 0 0 C W W W W W W w w -~ w -r _ ~ LL LL LL LL LL LL N 1- 1.. 1- L J Z Z Z Z Z Z Ll tJ U C.1 N In VI V1 O LL --~ w w ry -a w W W W W F- 1- -- F- ~ LL N N VI N V/ V/ LL LL LL LL Z Z Z ~ 2 W w r+ -+ -+ -+ w Z Z Z Z W W W W Ct CI CI O O D w w -~ ri F 1- F- F O J a O O O O O O w w H w O O O O z 1- F- F- 1- -- F- o 0 0 o u u u u LL OC ~ K K CC K tY C K tti Z Z Z Z ~ W W W W M -~ M M ~ M H M H ~y LL ~ O K fY K d' ~ Q: Y . LL LL a 6 a a w W o. a s o. a o. a a a a m m m m F " I -~ H H H F F- 1- F F- 1- F F- F- F- Z z Z Z H y N IA IA Z Z Z Z Z Z Z Z Z Z O O O O a a a a a W W W W W W W W W W w r~ w w 3 3 3 3 3 7 > > > > > > > > > H p. F !- J J J J J J J J J J a a a a Q Q a Q Q LL LL LL W LL LL LL ' ' LL I L Y . LL I L I L I L LL I L W W W W d ~ C d K W W W W W W W W W W a a a a o. a a s o. a a o. ~ g F- Z ~ ~ Z ~ O V H V V V O O am C i m = T = _ _ F m m = m m m m m = = m m m• m N Q 4 a a a a a a a a a tf ~t tY 6' ~ ~ V ~l Q.' K O: O: C' ~ d' K OC O; K N N C7 LI' N N N N (7 C7 L7 C7 () N N (D C7 (7 (7 e x s m ~ z z d 7 Y Y Y Y Y Y Y Y Y X Y Y O g ~ Y Y X Y E W W W W W W W W W W W W ~ W W W W H~ 3 3 3 3 3 3 3 3 3 N N W W w W 3 3 ; o 3 3 3 3 LL ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ n n n n n n n n n n n n n n n n L a W O ~' M Z N r. Q Z m E d J ~ d J a a ~ vl } m v ~ o ~ ~ o a z ai a .. ~ . .• . . ~ . ~ K w L N X N v ~ X H I n W W r u i d v ~ G ~+ Z 6 O Z Z p W 3 W ~ W W ~ W C 7 J J J } > l 7 J F O I O O 1 O a a I - F - > F - ~' Z Z o C vl H u r + . + X CI w m W g W W 1 - ~ W O W L 1 V p W W v / m o. o ~ o . . + o w ~ H LL ,. ., , ., x o: 3 V 1 g D v J Z ~ J ~ X X D w O W O w F 7 N p 1 - W . re O O W Z F F - N H H N w W a Z o C I - F - } a a Q' W O O v d O Q Z v J O: LL . W W O D W w a ; O J ~ m O = W m O ~ = W = O V V - + O W O u F - n. F - LL u F - a o . h F - u V a a o v l F - m .^- L w a o 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 >; 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 O Facility Name: Dubuque, City of STP Permit Number: 3126001 Outfall Number: 001 Ceriodaphnia and Pimephales Toxicity Effluent Testing 1. For facilities that have not been required to conduct toxicity testing by a previous NPDES permit, the initial annual toxicity test shall be conducted within three (3) months of permit issuance. For facilities that have been required to conduct toxicity testing by a previous NPDES permit, the initial annual toxicity test shall be conducted within twelve months (12) of the last toxicity test. 2. The test organisms that are to be used for acute toxicity testing shall be Ceriodaphnia dubia and Pimephales promelas. The acute toxicity testing procedures used to demonstrate compliance with permit limits shall be those listed in 40 CFR Part 136 and adopted by reference in rule 567-63.1(11. The method for measuring acute toxicity is specified in USEPA. 1993. Methods for .Measuring the Acute Toxicity of. Effluents to Freshwater and Marine Or ana isms. Fourth Edition. Environmental Monitoring Systems Laboratory, U.S. Environmental Protection Agency, Cincinnati, Ohio August 1993, EPA/600/4-90/027F. 3. The diluted effluent sample must contain a minimum of .17.4 % effluent and no more than 82.6 % of culture water. 4.. One valid positive toxicity result will require quarterly testing for effluent toxicity. 5. Two successive valid positive toxicity results or three positive results out of five successive valid effluent toxicity tests will require a toxic reduction evaluation to be completed to eliminate the toxicity. 6. Anon-toxic test result shall be indicated as a "1" on the monthly operation report. A toxic test result shall be indicated as a "2'! on the monthly operation report. DNR Form 542-1381 shall also be submitted to the DNR field office along with the monthly operation report. Ceriodaphnia and Pimepha]es Toxicity Effluent Limits The 30 day average mass limit of "1° for the parameters Acute Toxicity, Ceriodaphnia and Acute Toxicity, Pimephales means no positive toxicity results. Definition: "Positive toxicity result" means a statistical difference of mortality rate between the control and the diluted effluent sample. For more information see USEPA. 1993. Methods for Measuring the Acute Toxicity of Effluents to Freshwater and Marine Organisms. Fourth Edition. Environmental Monitoring Systems Laboratory, U.S. Environmental Protection Agency, Cincinnati, Ohio August 1993, EPA/600/4-90/027F. Revised: July 31, 1996 cwf Facility Name: Dubuque, City of STP Facility Number: 3126001 Pretreatment Compliance Schedule The City shall evaluate the adequacy of the existing pretreatment program local limits to meet the requirements of 40 Code of Federal Regulations (CFR).Part 403.5(c)(1). This evaluation of Local limits shall be based on the design flows used for the treatment plant improvements that were completed August 2, 1995. A written technical evaluation of the need to revise local limits shall be submitted no later than March 1, 1999. The written report shall be sent to: Wastewater Permits Branch Iowa Department of Resources ~Ienry A. Wallace Building 900 East Grand Des Moines, Iowa 50319 SLUDGE HANDLING AND DISPOSAL REQUIREMENTS 1. The permittee shall comply with all existing Federal and State laws and regulations that apply to the use and disposal of sewage sludge and with technical standards developed pursuant to Section 405(d) of the Clean Water Act when such standards are promulgated. If an applicable numerical limit or management practice for pollutants in sewage sludge is promulgated after issuance of this permit that is more stringent than a sludge pollutant limit or management practice specified in existing Federal or State laws or regulations, this permit shall be modified, or revoked and reissued, to conform to the regulations promulgated under Section 405(d) of the Clean Water Act. The permittee shall comply with the limitation no later .than the compliance deadline specified in the applicable regulations. 2. The permittee shall provide written notice to the Department of Natural Resources prior to any planned changes in sludge disposal practices. 3. Land application of municipal sewage sludge shall be conducted in accordance with criteria established rule IAC 567--67.1 through 67.11(455B). Facility Name: Dubuque, City of STP Facility Number: 3126001 Pretreatment Compliance Schedule The City shall evaluate the adequacy of the existing pretreatment program local limits to meet the requirements of 40 Code of Federal Regulations (CFR).Part 403.5(c)(1). This evaluation of local limits shall be based on the design flows used for the treatment plant .improvements that were completed August 2, 1995. A written technical evaluation of the need to revise local limits shall be submitted no later than March 1, 1999. The written report shall be sent to: Wastewater Permits Branch Iowa Department of Resources Henry A. Wallace Building 900 East Grand Des Moines, Iowa 50319 MAJOR CONTRIBUTLYG INDUSTRIES LIMITATIONS, iv10NITORING AND REPORTPi 1G REQUIREMENTS 1. You are required to notify the department, in writing, of any of the following: (a) ~ 180~~days prior to the introduction of pollutants to your facility from a major contributing industry. A major contributing industry means an industrial user of a treatment works that: (1) Has a flow of 50,000 gallons or more per average tivork day; (2) Has a flotiv greater than five percent (5%) of the flow carried by the treatment works receiving the waste; (3) Has in its waste a toxic pollutant in toxic amounts as defined in standards issued under Section 307 (a) of the Clean Water Act and adopted by reference in Rule 62.5(~SSB); or (4) Is found by the department in connection with the issuance of an NPDES permit to have ' a significant impact, either alone or in combination with other contributing industries, on the treatment works or on the quality of e$luent from the treatment works. (b) 60 days prior to a proposed ea~pansion, production increase or process modification that may result in the discharge of a new pollutant or a discharge in excess of limitations stated in the existing treatment agreement. (c) 10 days prior to any commitment by you to accept waste from any new major contributing industry. Your written notification must include a new or rerzsed treatment agreement in accordance with rule 64.3(5)(455B). 2. You shall require all users of your facility to comply with Sections 204(b), 307 and 308 of the Clean Water Act. Section 204(b) requires that all users of the treatment works constructed tivith funds provided under Sections 201(g) or 601 of the Act to pay their proportionate share of the costs of operation, maintenance and replacement of the treatment works. Section 307 of the Act requires users to comply with pretreatment standards promulgated by EPA for pollutants that would cause interference with the treatment process or would pass through the treatment works. Section 308 of the Act requires users to allow access at reasonable times to state and EPA inspectors for the purpose of sampling the discharge and reviewing and copying records. 3. You shall continue to implement the pretreatment program approved September 29, 1983, and any amendments thereto. -1. An annual report in the form prescribed by the department is to be submitted by March Ist of each year describing the pretreatment program activities for the preceding calendar year. Revised: April 1, 1994 avf STANDARD CONDITIONS 1. DEFINITIONS (a)7 day average means the sum of the total daily discharges by mass, volume or concentration during a 7 consecutive day period, divided by the total number of days during the period that measurements were made. Four 7 consecutive day periods shall ba used each month to calculate the 7-day average. The first 7- day period shall begin with the first day of the monW. (b)30 day average means the sum of the total daily discharges by mass, volume or concentration during a calendar month, divided by the total number of days during the month that measurements were made. (c)daily maximum means the total discharge by mass, volume or concentration during atwenty-four hour period. 2. DUTY TO COMPLY You must comply with all conditions of this permit. Any permit noncompliance constitutes a violation of the Clean Water Act and is grounds for enforcement action; permit termination, revocation and reissuance, or modification; or denial of a permit renewal application. Issuance of this permit does not relieve you of the responsibility to comply with all local, state and 'federal laws, ordinances, regulations or other legal requirements applying to the operation of your facility. (See 40 CFR 1??.41(a) and 567-64.3(ll) IACj You are required to notify the new owner of the requirements of this permit is writing prior to any transfer of title. The Director shall be notified in writing within 30 days of the transfer 8. PROPER OPERATION AND MAINTENANCE All facilities and control systems shall be operated as efficiently as possible. and maintained in good working order. A sufficient number of staff, adequately trained and knowledgeable in the operation of your facility shall be retained at all times and adequate laboratory controls and appropriate quality assurance procedures shall be provided to maintain compliance with the conditions of this permit. {See 40 CFR 1??.41(e) and S67 64.7(SJ(n IACj 9. DUTY TO PROVIDE INFORMATION You must furnish to the Director, within a reasonable time, any information the Duectoi may request to determine whether cause exists for modifying, revoking and reissuing, or terminating this permit or to determine compliance with this permit. You must also furnish to the Director, upon request, copies of any records required to be kept by this permit. 10. MAINTENANCE OF RECORDS You are required to maintain records of your operation in accordance with 567-63.2 IAC: 3. DUTY TO REAPPLY If you wish to continue to discharge after the expiration date of this permit you must file an application for reissuance at least 180 days prior to the expiration date of this permit. {See sa7~4.s(1)lacj 4. NEED TO HALT OR REDUCE ACITVITY It shall not be a defense for a permittee is an enforcement action that it would have bean necessary to halt or reduce the permitted activity in order to maintain compliance with the conditions of this permit. {See 167-64.7(s)~) IACj 5. DUTY TO MIITGATE You shall take all reasonable steps to minimize or prevent any discharge in violation of this permit which has a reasonable likelihood of adversely affecting human health or the environment. {See s67-64.71s)(J) L1e) 6. PROPERTY RIGHTS This permit does not convey any property rights of any sort or any exclusive privileges. 7. TRANSFER OF TITLE If title to your facility, or any part of it, is transferred the new owner shall be subject to this permit. (See 567.64.14 raCj 11. PERIVIIT MODIFICATION, SUSPENSION OR REVOCATION (a)This permit may be modified, suspended, or revoked and reissued for cause including but not limited to those specified in 567-64.3(11) IAC. (b)This permit may be modified due to conditions or information on which this permit is based, including any new standard the department may adopt that would change the required effluent limits. (see ss7.64.sp1)e tee} (c)If a toxic pollutant is present in your discharge and more stringent standards for toxic pollutants are established under Section 307(a) of the Clean Water Act, this permit will be modified is accordance with the new standards. (See s6f•64.7(s)(~ IACj The filing of a request for a permit modification, revocation or suspension, or a notification of planned changes or anticipated noncompliance does not stay any permit condition. 12. SEVERAB>iI.ITY The provisions of this permit are severable and if any provision or application of any provision to any circumstance is found to be invalid by this department or a court of law, the application of such provision to other circumstances, and the remainder of Wis permit, shall not be affected by such finding. STANDARD CONDITIONS 13.1lNSPECTION OF PRENIISES, RECORDS, EQI7IPMENT, METHODS AND DISCHARGES You are required to permit authorized personnel to: (a)Enter upon the premises where a regulated facility or activity is located or conducted or where records are kept under conditions of Wis permit. (b)Have access to and copy, at reasonable times, any records that must be kept under the conditions of this permit. (c)Inspect, at reasonable times, any facilities, equipment, practices or operations regulated or required under this permit. (d)Sample or monitor, at reasonable times, for the purpose of assuring compliance or as otherwise authorized by the Clean Water Act. 16. ADMIIVISTRATIVE RULES Rules of this Department which govern the operation of your facility in connection with this permit are published in Part 567 of the Iowa Administrative Code (IAC) in Chapters 60-64 and 120-122. Reference to the terns "rule" in this permit means the designated provision of Part 567 of the Iowa Administrative Code. 17. NOTICE OF CHANGID CONDTITONS You era required to report any changes in oxistiag conditions or information on which this permit is based: (a)Faciiity expansions, production increases or process modifications which may result in new or increased discharges of pollutants must be ,reported to the Director in advance. If such discharges will exceed effluent limitations, your report must include an application for a new permit. (ssa s67-60.7(s)(a) IAC} 14. TWENTY FOUR HOUR REPORTIl~IG You shall report any noncompliance that may endanger human health or the environment. Information shall be provided orally within 24 hours from the time you become aware of the circumstances. A written submission that includes a description of noncompliance and its cause; the period of noncompliance including exact dates and times, whether the noncompliance has been corrected or the anticipated time it is expected to continue; and the steps taken or planned to reduce, eliminate, and grevent a reoccurrence of the noncompliance must be provided within 5 days of the occurrence. The following instances of noncompliance must be reported within 24 hours of occurrence: (a)Any unanticipated bypass which exceeds any effluent limitation in the permit. {see as cmt tzz.aa[gl} (b)Any upset which exceeds any effluent limitation in the permit. {see ao cFit ~zz.aacnl} (c)Any violation of a maximum daily discharge limit for any of the pollutants listed by the Director in We permit to be reported within 24 hours. {see ao ctat Izz.aatgl} 15. OTHER NONCOMPLIANCE You shall report all instances of noncompliance not reported under Condition X14 at the time monitoring reports are submitted. (b)If any modification of. addition to, or construction of a disposal system ie to be made, you must first obtain a written permit from this Department. (sae s6z-6a.? mac} (c) If your facility is a publicly owned treatment works or otherwise may accept waste for treatment from industrial contributors see 567-64.3(5) IAC• for further notice requirements. (d)You shall notify We Director as soon as you know or have reason to believe that any activity has occurred or will occur which would result in the discharge of any toxic pollutant which is not limited in this permit. (Sae 40 CFR 111.4?(a)) You must also notify the Director if you have begun or will begin to use or manufacture ae as intermediate or final product or byproduct any toxic pollutant which was not reported in the permit application 18. OTHER INFORMATION Where you become aware that you failed to submit any relevant facts in a permit application. or submitted incorrect information is a permit application or in any report, you must promptly submit such facts or information. STANDARD CONDITIONS 19. UPSET PROVISION (a)Definitioa - "Upset" means an exceptional incident is which there is unintentional and temporary noncompliance with technology based permit effluent limitations because of factors beyond the reasonable control of the permittee. An upset does not include noncompliance to the extent caused by operational error, improperly designed treatment facilities, inadequate treatment facilities, lack of preventive maintenance, or careless or improper operation. Zl. BYPASSES (a)Definition -Bypass means the intentional diversion of waste streams from any portion of a treatment facility. (b)Prohibition of bypass, Bypass is prohibited and the department may take enforcement action against a permittee for bypass unless: (1) Bypass was unavoidable to prevent loss of life, personal injury, or severe property damage; (b)Effect of an upset. An upset constitutes an affirmative defense in as action brought for noncompliance with such technology based permit effluent limitations if the requirements of paragraph "c" of this condition are met. No determination made during administrative review of claims that noncompliance was caused by upset, and before an action for noncompliance, is final administrative•action subject to judicial review. (c) Conditions necessary for demonstration of an upset. A permittee who wishes to establish the affirmative defense of upset shall demonstrate through properly signed, contemporaneous operating logs, or other relevant evidence that; (1) An upset occurred and that the permittee can identify the cause(s) of the upset. (2) The permitted facility was at the time being properly operated; and (3) The permittee submitted notice of the upset to the Department is accordance with 40 CFR 122.41(1) (6) (ii)(B). (4) The permittea complied with any remedial measures required by Item #5 of the Standard Conditions of this permit. (d)Burdea of Proof. In any enforcement proceeding, the permittee seeking to establish the occurrence of an upset has the burden of proof. 20. FAILURE TO SUBMIT FEES This permit may be revoked, in whole or in part, if the appropriate permit fees are not submitted within thirty (30) days of the data of notification that such- fees are due. (2) There were no feasible alternatives to the bypass, such as the use of auxiliary treatment facilities, retention of untreated wastes, or maintenance during normal periods of equipment downtime. This condition is not satisfied if adequate backup equipment should have been installed in the exercise of reasonable engineering judgement to prevent a bypass which occurred during normal periods of equipment downtime or preventive maintenance; (3) The permittee submitted notices as required by paragraph "d" of Wis section. (c)The Director may approve an anticipated bypass after considering its adverse effects if the Director determines that it will meet the three conditions listed above. (d)Reporting bypasses. Bypasses shall be reported is accordance with 567.63.6 IAC. 22. SIGNATORY REQUIItENIENTS Applications, reports or other information submitted to the Department is connection with this permit must be signed and certified as required by 5674.3(8} IAC. 23. USE OF CERTIFIED LABORATORIES Effective October 1, 1996, analyses of wastewater, groundwater or sewage siudge that are required to be submitted to the department as a result of this permit must be performed by a laboratory certified by the State of Iowa. Routine, onsite monitoring for pH, temperature, dissolved oxygen, total residual chlorine and other pollutants that must be analyzed immediately upon sample collection, settleable solids, physical measurements, and operational monitoring tests specified in 567.63.3(4) are excluded from this requirement. J APPENDIX B ANTICIPATED WLA/PERMIT LIMITS FOR DUBUQUE WPCP EXHIBIT 3 ENVII2ONMENTAL SERVICES DIVISION WATER QUALITY BASED PERMIT LIMITS WORK REQUEST FORM & INSTRUCTIONS 1 Date Re uested: 10/16/2007 2 Date Needed: 11/1/2007 3) Wasteload Allocation Priority Justification: We are in facilities planning and if the limits can be determined in less than 30 days it would be helpful to keep the process moving. _ -- _ _ . ~~ ,. y`~r~ ~- ~~.. _S~L-~ U_ vIT:~ C .ITY--:[IV11,LQ,'= iUN _ _ ~~<;~_ =~ __r* "~ •~1~`~:. '` 4 Facili Name: Ci of Dubu ue Water Pollution Control Plant 5 NPDES/Sewa a File Number: 3126001 6 Facili Location Section:6 Townshi :88N Ran e: 3E Latitude: De : 42 Minutes: 28 Seconds: 10 N Lon itude: De : 90 Minutes: 39 Seconds: 35 W 7) Description of Industry and Principal Products: 8 Field Office: Manchester 1 9 Coun :Dubu ue 10) Treatment Type: Mechanical 11) Other Treatment*: 12) The WLA is being requested 13) Map Included (Required 14) Toxicity %Required for: for anew/proposed facility: (For Major Facilities)*: Upgrade to an Existing Facility ^ ~I~) ~~ ': ~. a~w~ L ~ ~«~~°°A~ .. ~ ~< <~~, ~n1c:~~ <, ,=~ I~t~~ ~ ~: -: Lt, g~tv~` ; ~~~ = ,_1 ,~~ I ~~ . to n~ ~~~w~~' .,_YO ~~.{~ n iM ors ~ _ ~- m~ , ~n/ ~ ~ _ KY_~ Uiitfall#;(101 r° 9.144 13.486 na 42 28 16N 90 38 56 W L wN.t '~ Uutfall Desci'ipt~on ''' Domestic Wastewater 1 -r {~k ..-... -. Z fi btrc un Nuhroi ~ , Mississippi River , ~ ti Cliitisific~ltion of ~~;x' Al, B(WW-1) .Recce m~.Sti cam ~Uutfall # ~ ~~, Odtfall Descr~pt~on 1~ Select: ~ tifrcam Ncriro~ {. ~' CI~i5silication of ~:~ Select: Rccci~ing Stream , Outfall Uescnphon ~.,;` Select: '~J,Stri~anrNctwork " ('las.ifiaition of " ~_ ~ Select: " Receiving Sti e un 16) New WLA Request Regular Diffuser Flow Variable ~ Study MZ /o Z Site Specific pH and Temperature Options ^ ^ ^ ~ : ID /o. ^ 17) Previous WLA Qual II E Diffuser Flow Variable ~ Study MZ/o: Z Site Specific pH and Calculations ^ ^ ^ ID%: Tem erature ~ Completed* *Indicates that this information is optional and may need access to. a facility's file to fill out Revised May 2006 EXHIBIT 3 r ~~ ENVIRONMENTAL SERVICES DIVISION WATER QUALITY BASED PERMIT LIIVIITS WORK REQUEST FORM & INSTRUCTIONS 18)* For Facilities who will or may discharge TRC: 19) UV Disinfection - (No TRC Time of Travel within the sewage pipe (from sampling point to outfall) if Required) applicable - (it will be an assumed-zero if not filled out) (ADW)Time of Travel: or pipe length: Velocity in pipe(ft/s): ^ (AWW)Time of Travel: Velocity in r 3} ~' _. . ~ ..r-a y 20 Is the waterbod * Im aired: ^ Unim aired: 21) If the waterbody is impaired, what is it impaired for: 22) Status of the TMDL*: r , ~- ~ - - 23 Parameter Fre uency Parameter Fre uency CBOD ^ Common Metals Ammonia ^ Cadmium ^ 1/week E. Coli ^ Chromium ^ 1/week Fecal Coliform ^ Copper ^ 1/week TDS ^ 1/month Cyanide ^ 1/week Chloride ^ Lead ^ 1/week TRC ^ Nickel ^ 1/week Silver ^ 1/week Priorit Pollutants Zinc ^ 1/week ALL: ^ ^ Others ^ Iron ^ ^ pH ^ ^ Temperature ^ ^ D.O. ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ~ _ -~`_Submitte~l~~,.rm~~l Dnt~r ,, '"' - _ - 'unctntr~t - - - - a Enl %I ~~~r~ F {.- - 24)* TDS: Chloride: ~ ~ ? `. S G' (:'T' "a i € . ~r~ N I). C'~O . ~ ~``C"~~ ~.: t y ~i~' ~~. - Requested By: Select: Contact Information (for consultants):. Randy Wirtz IDNR W W Engineer Name: Strand Associates, Inc. 910 W. Wingra Drive, Madison, WI 53715 Eii~~m°ail for consultants :Rand .Wirtz(a),strand.com Ph. (608)251-4843 ~~r1Cj C~It1011 i~ Ollllll~llt5 ~~"q,~ ~ ~ - _ - _ - rk .. ~ ~k~" ~v~' s~-~: .,~,,.. T.a. ~t.. ... 4~ "~1~3.`, .:1 .. ~ .. ~ _ -. - =gin ~.a~`.fCilta :~`C a,~?:4 ~s .. , 1:. .o ~ ~...w,~ ulatgm I yun il~ni (I'IJ) ~~ ~~,~; _` ~• *Indicates that this information is optional for consultants and may need access to a faciliy's.file to fill out Revised May 2006 EXHIBIT 3 ENVIRONMENTAL SERVICES DIVISION WATER QUALITY BASED PERMIT LIMITS WORK REQUEST FORM & INSTRUCTIONS The following is a step by step guide for the completion of the Iowa Department of Natural Resources Water Quality based permit limits work request form. If the required information is not filled out completely, it may take longer for the request to be completed by the Wasteload Allocation (WLA) staff of the Water Resources Section. Please allow for the request to take up to 30 days for completion. Varying levels of complexities may take up to 60 or more days for the completion of the wasteload allocation. If the wasteload request needs to be completed sooner than 30 days, please state the reason in part three of Section I of the form. Instructions• Section I 1. Date Requested -The date the WLA was filled out and sent to the DNR WLA staff. 2. Date Needed -The date the WLA request would need to be back to the requester. 3. Wasteload Allocation Priority Justification (optional) - As stated above, a wasteload allocation usually takes up to 30 days to complete with some taking as long as 60 or more -days for completion. If the wasteload allocation needs to be completed before the normal ~~ processing time, a justification statement needs to be included in the wasteload allocation ~~ priority area. Section II 4. Facility Name -The name of the facility being requested. 5. Sewage File Number (optional for consultants) -This is the number assigned to the facility as it corresponds to the sewage/NPDES file record. If this is a new/proposed facility, a number may not have been assigned to the facility. 6. Facility Location -The description of the location of the facility (Section/Township/Range). This location is not the location of the discharge/outfall pipe, but the facility itself. This information can be located using the following websites: http://ortho.gis.iastate.edu/ htip://www.topozone.com/ http: //mapserver.maptech.com/api/espn/index.cfm 7. Description of the Industry and Principal Products (apply only to Industrial Dischargers) - If it is an industrial discharge, please describe what kind of industry, for example, ethanol plant or power plant and the plants principal products. 8. Field Office -There are 6 different field offices in the State of Iowa with a corresponding number: 1-Manchester, 2-Mason City, 3-Spencer, 4-Atlantic, 5-Des Moines, and 6- Washington. Either the number of the field office or the name of the field office will work in this form. 9. County -The name of the County in which the facility is located. Revised May 2006 EXHIBIT 3 ENVIRONMENTAL SERVICES DMSION WATER QUALITY BASED PERMIT LIMITS WORK REQUEST FORM & INSTRUCTIONS 10. Treatment Type A treatment type can be one of the following: Aerated Lagoon, Mechanical plant, Industrial facility, Trickling Filter, Sand Filter, Rotating Biological Contactor, Sequencing Batch Reactor, or None. If the treatment type is not listed here, please enter the treatment type in option number 11 "other treatment". If this is a new/proposed facility or a proposal for a facility upgrade, please indicate which type of treatment the facility plans on providing. 11. Other Treatment (optional}- If the treatment type wasn't, specified in the drop-down box "treatment type", then use this category to fill in the treatment type being used. 12. Reason for WLA request - By selecting one of the following categories: new/proposed facility, existing facility, or upgrade to an existing facility, the wasteload staff would know if the sewage/NPDES file contains any previous wasteload options that may need to be considered. New/Proposed Facility -This facility is not currently an existing facility. Existing Facility - A treatment plant that has already been constructed and is currently in operation. 13. Map Included (optional for an existing facility) - A check needs to be added if a map was included with the request. A map is needed for use with anew/proposed facility. If the facility already exists, a map does not need to be provided with the request form. 14. Toxicity % (optional) - If the facility is considered a "major" facility, the wasteload allocation staff will provide a toxicity percentage spreadsheet along with the final limits when a municipal plant discharges more than 1.0 mgd (AWW for municipal treatment plants). For industrial facilities, a "major" discharge is determined on asite-specific basis and will be reviewed by NPDES staff. 15. This is the location and information needed for the outfall. If there are multiple outfalls, please fill out each outfall accordingly. If each outfall has different parameters, please fill out a separate. wasteload allocation request form for each outfall. To find. the Latitude/Longitude of the outfalls, please refer to the websites found in instruction number 6. (l~, ~ - t im a ~;.~~ 3~<.~. ~, _ SAD ~*;~` tM ~ ~'~~tv~ti; ~* ~cu[, ntc:t) ~~ (~ ) ~~1( t)) " "A1V1~ ~ lUi , r~,'rti ttitii~~ ~m,"~,,~ ~'S . I)'~'z 9~p~ :y ~~^ ~ b Lon~ttuat~ < '-~~~ ~4~~ k, . 6it1 ~Il~#~'~ Get "' .5 1.5 42 17 35 32 12 25 ~(hitf iII,~Dcs~~ i~ttion~~~s 1~ M 4~ Sewage _ ~ Z ~ 1. ~~ 1~1: ii ti - ~ t i e ~ ~r~ N= ~w Unnamed Tributary to Cedar River ` ~~~I~.sdic~tion~ot ' '_"~ ~Recervri5`~ Stream' Ad, B(WW-1) **Indicates that the ADW and AWW flows for municipal and semi-public facilities need to be approved by the Iowa Department of Natural Resources Wastewater Construction Section to be used in a wasteload allocation for an NPDES permit. The definitions for ADW and AWW are provided in Section 14.4.5.1 of the Iowa Wastewater Facilities Design Standards. The ADW and AWW are discharge flows. For Controlled Discharge Lagoon (CDL), multiply the 180-day Revised May 2006 EXIiIBIT 3 ENVIRONMENTAL SERVICES DIVISION WATER QUALITY BASED PERMIT LIlVIITS WORK REQUEST FORM & INSTRUCTIONS AWW with a factor of 10, since maximum drawdown rate for a CDL is restricted to the value of 10 times of the AWW flow. ADW =Average Dry Weather Flow (MGD) AWW =Average Wet Weather Flow (MGD) MGD =Millions of Gallons per Day 16. New WLA Request Options - If. the request is for anew/proposed facility, a check needs to be placed in the box if these options need to be included within the wasteload request. If the request is to include a Mixing Zone study, please include what mixing zone percentages need to be included along with the mixing zone study report. 17. Previous WLA Calculations (optional) - If the previous wasteload request included either a Qual II model, Diffuser, or Mixing Zone Study, an "X" needs to be placed in that category. If this request is coming from a consultant, a previous WLA request or sewage file may not be available to them, so this information is not expected to be included. 18. TRC disinfection statement (optional) - If TRC decay needs to be considered within the pipe, or the facility is currently using TRC for disinfection, or will be using TRC for disinfection in the future, a travel time needs to be included with the form. This is the pipe distance from the monitoring location for TRC to the outfall location. 19. UV Disinfection - If the facility uses UV, a check needs to be placed in this category. Section III 20. TMDL(optional) - An "X" needs to be placed in the Impaired or Unimpaired category. If the waterbody doesn't currently have a TMDL, then skip the next two. If the waterbody is impaired, then the next two questions should be completed. 21. Explanation of the impairment for that waterbody (optional) -This information could be gathered from the Iowa Department of Natural Resources 303 (d) report. 22. Status (optional) -Is there a TMDL being worked on for this stream, or is there a TMDL being scheduled for this stream. Revised May 2006 EXHIBIT 3 ENVIItONMENTAL SERVICES DIVISION WATER QUALITY BASED PERMIT LIlVIITS WORK REQUEST FORM & INSTRUCTIONS Section IV 23. An "X" needs to be placed in the column after the parameter if that parameter is being requested. Please make sure to include all the pollutants in the pre-treatment agreement. If there is a sampling frequency (other than the sampling frequency already determined by department staff), please contact NPDES staff to discuss these options. Specific toxics (other than what was provided) need to be added in the appropriate space (Priority Pollutants). The sampling frequency is based on the population equivalent (PE) in Chapter 63 of the Iowa Administrative Code. The design PE is calculated using peak monthly organic loading. The population equivalent should be included within the "Additional Comments" section at the bottom of the WATER QUALITY BASED PERMIT LIMITS WORK REQUEST FORM. 24. Submitted Sample.Data (optional) -The new site-specific TDS and Chloride standard was adopted on June 16, 2004. The site-specific TDS approach would first consider a guideline value of 1000 mg/1 as a threshold in-stream level at which. negative impacts to the uses of the receiving stream may begin to occur. Chloride is a constituent of TDS. At higher levels, chloride could cause toxicity to aquatic life. Thus, the WLAa~„ ~e and WLA~~o~;~ are calculated to evaluate the potential negative impacts. If the facility has already taken either TDS or Chloride data, those concentrations need to be included with the WLA Request form. If the facility is a new/proposed facility, the data would not be available and therefor would not be expected to be included with the wasteload request. Section V Contact Information: Example Requested By: Joe Smith Email: Joe.Smith(c~,hotmail.com Contact Information: Joe Smith M & M Engineering Des Moines lA, 50320 -phone (515) 555-1212 Additional Information -This section is for any other information that the requester feels should be included with the work request. Or, if the requester is looking for other options to be included with the wasteload allocation, it needs to be specified within this space. Revised May 2006 October 18, 2007 WLA/Permit Limits for the City of Dubupue Water Pollution Control Plant These wasteload allocations and water quality based permit limitations are for the City of Dubuque Water Pollution Control Plant. The wasteload allocations/permit limits are based on the newly adopted water quality standards (March 22, 2006, awaiting EPA approval), the 2002 Permit Derivation Procedure and the 2000 ammonia criteria. The TDS wasteload allocation/permitlfmits are based on the site-specific approach that became effective on June 16, 2004. 1. BACKGROUND: The facility discharges directly into the Mississippi River. Based on the old water quality standards the Mississippi River was designated as a Class Al, B(WW) stream. According to the new water quality standards, it is now designated as a Class Al, B(WW-1), and HH waterbody. The annual critical low flows in the Mississippi River were estimated based on the drainage area ratio method and flow statistics obtained at USGS gage station 054205001ocated on the Mississippi River at Clinton, Iowa. The annual critical low flows are in Table 1 below. Table 1: Annual Critical Low Flows in the Mississi i River at the Outfall of the Facility ' Location D.A. Annual Critical Low Flows (cfs) ' (mil) 1Q10 7Q10 30Q10 Outfall 81,600 9,018 9,723 12,964 USGS Ga e 05420500 85,600 9,460 10,200 13,600 ~ s : USGS gage station data ~: estimated based on the drainage area ratio '` 2. CALCULATIONS: As requested by Strand Associates, Inc., the wasteload allocations/permit limits for this outfall were calculated based on an Average Dry Weather (ADW) design flow of 9.144 mgd and '~ an Average Wet Weather (AWW) design flow of 13.486 mgd. The water quality based permit concentration limits are derived using the allowed stream flow and the ADW design flow, while loading limits are derived using the allowed stream flow and the AWW design flow. Ammonia: Standard stream background temperatures, pH's, and concentrations of NH3-N were mixed. with the discharge from the facility's effluent pH and temperature values to calculate the applicable instream WQS criteria for the protection of the Mississippi River. Since the ratio of stream flow to discharge flow is greater than 5:1, 2.5% of the 1Q10 flow and 25% of the 30Q10 flow in the receiving stream were used as the ZID and MZ, respectively. The Mississippi River is a Class B (WW-1) stream. Early life protection will begin in February and run through September. The monthly background temperatures, pH, and NH3-N concentrations shown in Table 2 were used for the wasteload allocation/permit limits calculations based on the Year 2000 ammonia criteria. 1 By: John Warren W:\SHARED\NEWWLA\Dubuque - 63126001\10-18-2007 \Dubuque 2007 Writeup.doc Table 2: Background Temperature, pH and NH3-N Concentrations For Use with Year 2000 Ammonia Criteria 1vi~,ntlis~ __ pll` Te~I~perafi~re NH-N Jan. 7.8 0.6 0.5 Feb. 7.7 1.2 0.5 March 7.9 4.3 0.5 A ril 8.1 11.7 0.5 Ma 8.1 16.6 0.5 June 8.1 21.4 0.5 Jul 8.1 24.8 0.0 Au st 8.2 23.8 0.0 Se t. 8 22.2 0.5 October 8 12.3 0.5 November 8.1 6 0.5 December 8 1.6 0.5 Table 3 shows the statewide monthly effluent pH and temperature values for a mechanical facility. Table 3: Standard Effluent H & Tem erature Values for a Mechanical Facility Monihs.~ l?H ` Tempcraturc ~°~~~~ Jan. 7.67 12.4 Feb. 7.71 11.3 March 7.69 13.1 A ril 7.65 16.2 May 7.67 19.3 June 7.7 22.1 Jul 7.58 24.1 Au ust 7.63 24.4 Se t. 7.62 22.8 October 7.65 20.2 November 7.69 17.1 December 7.64 14.1 CBODS/D.O.: Based on the stream assimilative capacity for CBODS, 201bs/day/cfs, and the 7Q10 flow for assimilation, the water quality based limit is greater than 2,500 mg/1 of CBODS. Thus, CBODS limits set at secondary treatment levels will not violate water quality standards. TRC and Toxics: The TRC and Toxics wasteload allocations will consider the procedures included im the 2000 revised WQS. Important to TRC and toxics is the use of the 1Q1.0 stream flow in association with the acute wasteload allocation calculation. The chronic WLA will continue to use the 7Q10 stream flow in its calculations. 2 By: John Warren W:\SHARED\NEWWLA\Dubuque - 63126001\10-18-2007 \Dubuque 2007 Writeup.doc E. coli: The facility discharges into a Class (A1) water body. The water quality standard for E. coli in a Class (Al) waterbody is a Geometric Mean of 126 org./100 ml and a Sample Maximum of 235 org./100 ml from March 15`" through November 15~. TDS: The site-specific TDS standard was adopted on June 16, 2004. The site-specific TDS approach would first consider a guideline value of 1,000 mg/1 as a threshold in-stream level at which negative impacts to the uses of the receiving stream may begin to occur. Sources of TDS potentially elevating a receiving stream above 1,000 mg/1(TDS) would be required, upon application for a discharge permit or permit renewal, to clearly demonstrate that their discharge will not result in toxicity to the receiving stream. The guideline value applies to both the Zone of Initial Dilution (ZID) and the Mixing Zone (MZ). The discharge flow of the facility is not greater than 5 times the 7Q10 stream flow; therefore, 25% of the 7Q10 flow of 9,723 cfs and 2.5% of the 1Q10 flow of 9,018 cfs in the Mississippi River were used as the MZ and ZID, respectively. The allowed effluent TDS concentration to meet the 1,000 mg/1 TDS threshold value at the boundary of the ZID is 12,156 mg/1 and the allowed effluent TDS concentration to meet the 1,000 mg/1 threshold value at the boundary of the MZ is 121,285 mg/1. If the effluent TDS levels are greater than 12,156 mg/1, an acute WET test is required and if the effluent TDS levels are greater than 121,285 mg/1, a chronic WET testis required. The background TDS concentration is assumed as 300 mg/1. Chloride: Chloride is a constituent of TDS. At higher levels, chloride could cause toxicity to aquatic life. Thus, the WLAa~ure and WLA~~o~;° are calculated to evaluate the potential negative impacts. The acute and chronic threshold values for chloride for aquatic life protection are 860 mg/1 and 230 mg/1, respectively. Since the Mississippi River is a designated stream, it is afforded protection against both acutely and chronically toxic conditions. The discharge flow of the facility is not greater than 5 times the 7Q10 stream flow; therefore, 25% of the 7Q10 flow of 9,723 cfs and 2.5% of the 1Q10 flow of 9,018 cfs in the Mississippi River were used as the MZ and ZID, respectively. The allowed effluent chloride concentration to meet the 860 mg/1 of chloride threshold value at the boundary of the ZID is 14,088 mg/1 and the allowed effluent chloride concentration to meet the 230 mgll threshold value at the boundary of the MZ is 34,597 mg/1. If the effluent chloride levels are greater than 14,088 mg/l, an acute WET testis required and if the effluent chloride levels are greater than 34,597 mg/l, a chronic WET test is required. The background chloride concentration is assumed as 30 mg/1. 3. PERNIIT LIMITATIONS: -Based on the Year 2000 Ammonia YYater Quality Standards, 2002 Permit Derivation Procedure and 2006 water quality standards. The following table shows the Water Quality Based permit limits for the City of Dubuque Water Pollution Control Plant. These limits reflect the use of the year 2000 WQS and the 2002 Permit Derivation Procedure. 3 By: John Warren W:\SHARED\NEWWLA\Dubuque - 63126001\10-18-2007 \Dubuque 2007 Writeup.doc Table 4: Water Quality Based Year 2000 Ammonia Criteria and 2002 Permit Derivation Procedure Permit Limits for the City of Dubuque Water Pollution Control Plant 1?ollutant" '.: Avei~a~e ~ - Co~ic.`= (m~/I) ~ ~' hlaxinuim Coiic. (nc/1) ~: Average Loadin~'~ - (lhsld) Maximum ~ °- Loadu~t~ = (lbs/d) 5arrplind Fiz~jiency '.(tncintli}~.' CBOD/D.O. Second Treatment Levels will not violate WQS Ammonia- N January 201 201 15,876 15,876 - Febru 236 ~ 236 18,541 18,541 - March 169 169 13,406 13,406 - A ril 120 120 9,785 9,785 - Ma 119 119 9,705 9,705 - June 118 118 9,591 9,591 - July 131 131 10,702 10,702 - Au ust 110 110 9,049 9,049 - Se tember 144 144 11,624 11,624 - October 143 143 11,503 11,503 - November 119 119 9,628 9,628 - December 143 143 11,543 11,543 - TRC 0.558 0.558 54.7 54.7 30/month Bacteria Geomean (#or ./100m1) Sample flax (#or ./100m1) E. coli 126 235 March 15th -Nov. 15th - TDS If TDS > 12,156 mg/1, an acute WET test is required If TDS > 121,285 m 1, a chronic WET test is re uired Chloride If Chloride > 14,088 mg/1, an acute WET test is required If Chloride > 34,597 m 1, a chronic WET testis re uired If no WET tests are done, the following limits may a ly TDS 12,156 12,156 1,367,263 1,367,263 1/month Toxics Please see attached s readsheet 4/month WET Test Dilution Ratio for TDS/Cl WET Test Effluent % Dilution Water. Acute 5.9 94.1 Chronic 0.6 99.4 The department prefers that the facility conduct the WET tests with 100% effluent and the tests be done at a series of different dilutions according to EPA guidance. They should report the NOAEC and the LC50 for the acute test and the NOAEC and IC25 for the chronic test. 4. MAJOR FACILITY EFFLUENT TOXICITY TEST REQUIREMENTS: Since this is a major facility an annual acute toxicity test is required. The following dilution percentage shall be required. Use 13.6% effluent and 86.4% dilution water. 4 By: John Warren W:\SHAIZED\NEWWLA\Dubuque - 63126001\10-18-2007 \Dubuque 2007 Writeup.doc InputData Wasteload Allocation/Permit Limits for Toxics Based on New Critical Flows and 2000 New Permit Derivation Procedure Facility Name: Treatment type: Stream Name: Stream Designation: Flow ADW Flow AWW Flow 7Q10 1Q10 Effluent Variability Value Mixing Zone ~ Standard For Instreams Staridarc1 For Mississippi & Missouri 100% Final Mixing Zone cfs 14.146 20.863 cv n STD STD4 STD n ~,w~ -- 0 C~`- 0.555 0.294 0.294 hli<l: ADW AWW ZID MZ ZID MZ 0.025 0.25 0.025 0.25 0.01 0.1 0.01 0.1 1 1 1 1 ~f1 ~,~~. _ ~ ~~, ,~~ ~ 0. s: 1 * * * *The Following is for Dialog Use by VBA * * * * * * * General Use 2 Stream Designation 1 Treatment Type 2 Mixing Zone 2 Human Health TRUE Class C FALSE Ph Value for PCP 8 TDS Monitoring Data Avail 2 Chloride Monitoring Data A 2 Page 1 ENVIRONMENTAL SERVICES DIVISION WATER UALITY BASED PERMIT LIlVIITS ~` .;fir t _ ~~ `'.~~~ ~:`~~ ;5,~ (~N a fWATE QU:4ti :. ASED~PF~RIIUT ~' T~- .~~'"'` ~~ 4~ac~i yNam C~y~ot D~6~: ~. e .:°atv ollution t,~i~itfiol:Yl~nt , ,.~ ~i '~:~ `~ '1-~u :,1 ~~r'~~„_ ~~~ ~~.:,~i?Ua 11e~.;..~u~~bel: _b,-~ ~~ 6. Parameters Ave. Conc. Max Conc. Ave. Mass Max Mass (Ibs/d) Samples Per Month mg/1) (mg/1) (lbs/d) if CAI 1VO~n(])~ ~' + ~' ~. f~w ~~:"1 II]Q¢(~ FA~~W "1"~ '~~6 I11aa(1 Y~ ' i i °; ~ CBODS/D.O. Seconda Treatment Levels will not violate WQS Ammonia-Nitro en Janua 201 201 15,876 15,876 Febru 236 236 18,541 18,541 March 169 169 13,406 13,406 A ril 120 120 9,785 9,785 Ma 119 119 9,705 9,705 June 118 118 9,591 9,591 Jul 131 131 10,702 10,702 Au ust 110 110 9,049 9,049 Se tember 144 144 11,624 11,624 October 143 143 11,503 11,503 November 119 119 9,628 9,628 December 143 143 11,543 11,543 Bacteria Geomean #Or ./100m1 Sample Max #Or ./100m1 E. coli 126 235 March 15th-Nov. 15th TRC 0.558 0.558 54.7 54.7 30/month TDS If TDS > 12,156 mg/1, an acute WET test is required If TDS > 121,285 m 1, a chronic WET test is re uired Chloride If Chloride > 14,088 mg/l, an acute WET test is required If Chloride > 34,597 m 1, a chronic WET test is re uired If no WET test are done, the followin limits ma a 1 TDS 12,156 12,156 1,367,263 1,367,263 1/month Toxics Please see attached s readsheet 4/month Stream Network/Classification of Receiving Stream: Mississippi River (A1, B(WW 1), HH) Date Done: 10/18/2007 Annual critical low flows in the Mississippi River at the point of discharge: 30Q10 flow 12.964 cfs, 7Q10 flow a 9.723 _cfs, 1Q10 flow 9.018_ cfs Excel Spreadsheet calculations [ ] Qual II E Model [ ] Qual II E Modeling date [ ] Performed by: John Warren A roved by: Connie Dou Comments For the acute WET test use 5.9% effluent and 94.1% dilution water. For the chronic WET test use 0.6% effluent and 99.4% dilution water. W:\SHARED\NEWWLA\Dubuque - 63126UU1\1U-18-"lUU7\WLA Kequest uutYUt.aoc y_ N y O A ~` M 0 t0 O W t~ 0 O1 r 001 0 N 0 f0 ~ V e~ h V~ M M M a0 N h 0 I~ ~ N O (O M 00 f0 N N h 01 ~ r 0 O 'a t0 'V' O 10 OO M 1~ h O N N 01 M 00 N M 0 OD 00 O (O OD N (O M (0 f0 r f~ h r 0 0 00 '~i N N N O 0 'Q N O f~ O N O O OD h O M O 0 N M 0 V ~~OO (O ~ O ,t+ y C ~ y N ~^ N ~ 0 Y7 N ~ 1Ci f0 r 0~ ~ O ~ 0 7 0/ ~ 00 00 T ~ ~ D N O h O N N Oi M M 0 ~ W ~ N ~ ~ O ~ N h fM0 N ^ 10 r 0~1 N M m M h N ~ 0) ~ ~ 0 h V' 000 OOi O f0 a 0 N b C Oi O M Oj y ~ G h r N W ~ M ~ OND N O C ~ M ~ <O N ~ O 9 ~ ~ N N 10 f~ O ~ h O O G N O 10 O ~ M ~ OV l•} O ~ C ~ ^ ~ O r C7) tp ~ ~ O N O M N a0 N N C L N N M N r N r r r y Z d J y M y T h aD f0 CA h S r ~ 00 N 0 h V h ~ M M N h h ~ N 0 fO M N ~ N h ~ rao O V ~ O m M h O N N M v 0 ao 00 f0 W M0 M t0 ~h O h ~ f0 0 rn 01 v N m h W 01 fO f0 M O ~ T N ~ 10 ~ O 1 .. 7 O 9 ~ SS y y MV, E y 1~ 0 M '7 (G ~ h V' V' ~ 0 _ N O M 0 V; O O 00 '~f 0 OO ~O M aO ~ 0 0 00 00 a0 M 10 M N 01 O N 0 O I~ 0 O~ N N O N M M CA ~ h W ~O m O O 0 ~ ( O I~ O O f~ OD N 1~ r M O CV ~ O OD 0 1 N N f0 O O f~ f0 f~ O ~ O 1~ 10 O O 00 N I~ M M f0 CA O N M O Ol N t1 Q 01 d h > G O ~ 00 N ~ ~p M O h N ~ M N 'V O 4i M d) fC O O CA M O f0 I~ ~t N h O 0 CA V h r 1 1 O O f0 M Oj 0 h ~ V ~ M O M O O f0 I~ (O V O 0 Oi h c0 $ 0 N 00 N 0 W N C 0 oa Q N N M N r N C M N O r r N V/ r 0 r` C C C C ~ M O O O N r 10 N C 01 'Q N y C y N CA M 10 OD h 10 0 M ~ 01 N '7 (O D) CA 00 CA N N Q1 10 h W 7 W 00 c0 ~ N M 00 N O O 10 '7 t0 N 0 01 01 h O t0 M O 0 0 M f~ M O c0 V ~ M M N ~~{{ 00 0 M O 7 7 01 ~ h 0 O y +~ 10 A ~ O -_ N N OD f0 M 0 M 00 00 N ~ (0 h M f~ 'Q (0 h 0 M N O M M O M ~ O O h N 0 0 f0 M h D1 N OD 0 O O O W N N N V M N O N 0 O M 0 N 0 0 O N M M W h f~ N O O 10 1[7 00 N (0 O ~ 10 O 0 N f0 h M OO O `7 O f0 O N h N 10 h ~/ N m> ~ •N E M ~~ 0 h ~ E O N ~0 f0 ~ ~ ~ 0 N N ~ 0 0 0 f0 W rn n N h f0 O O u> N O f0 tO ao h O W N ~ V O M ^ O ~ 00 V M ~ ro N N 0 0 0 N O O O O n N n N n ~ h O n r- ~ N N h ~ f0 0 1n M I~ M M O ~ O N O r u'~ h ,+ ~ E Q J ti , V. M 0 Oj y0 t0 01 O O 0 0 M pj N O ~ ~ c M 0 O 00 O O H N p N O O ( O h O O ~ O V 0~ 0 7 0 N ~ 0 1 N f~ V ' S O N Oj ~ O o f0 J C M N ~ N O M O r N M G O O C C r O M 0 (V O O) C7 O O r G O O O O r r C r C r N M lM ,N F O (,) M N ^ t0 00 f0 M ( N f0 M 01 00 N f~ N T OD h 0 N (O I~ 00 f0 W M N M 0 ~ 0 M f~ f~ N O 0 N 01 01 f0 ~' t0 I~ a1 N h O OD 00 01 10 O M O N N M V M 11i 0) M M f0 O M O N M O 0/ t0 N a M a1 h I~ 0 4Y O N 0 O f0 V M N 10 O 0 (O M N ~ O I~ O h N N 40 10 N N ~ W Of ~ f0 O 0 t0 a ( ~ N 0 01 ~0 O N (0 M W O 01 I~ 0 ~ W W N f0 O O N ~ t h W 0 O h 0 0 10 1~ 0 ~ h O N h a a Q E O ~^ ~ f0 ~ Oj ~ N N O ( ~ OO O O O ~ n M M ~ N O O N ~ 0 ~ M M ~ W M ~ M O O n N~ M N ~ h ~ h 0 O 0 O 0 O O O ~ ~ ~ O CV O~ O~ 0 D h Q 0 D at N M 1~ W ~ ~ O N ~ ~ 0 O o t0 N fV ~ N C M G r N M G O O C 10 r C M t0 OV o1 Oi O O O O r 0~ G O OV O M r 0 M p ~j M to M t) O , ~ W 00 0 0 0 0 N a r ~ 0 00 N f~ Q1 M f0 0 f0 t0 M M M 0 0 ~ M 0 01 1~ N O d' O to O 0) O h O 00 M 10 O 00 O h M h M O N 01 h 0 O N O 0 V 01 0 0 00 ~ W S M W r N s O t0 1~ ~ C N O Ol ^ O ~ M 0'1 0 ' S p O 00 ~ 0 N 0 ~ 10 M h ' ' 0 ~ a 0 W n N ~ 01 ~ M V M ~ 4W7 R ^ h W m 0 W ~ OD ~ N' h O O ~ N ~ O ~ O M O O N M OMD M W 01 N ~ t~ W M 0 V O O 0 0 ~~ O V ~ 'O ( 0 'h h O ~~ N ~ ~ 0 0 N 0 1 O N V O O 0 1~ O 01 O 00 10 N M 00 ~ N O 00 ~ V; L r U ~ ~ j M h r f~ O N O O r N N O r Q r Q O ~ N r C N V r (O (O O G a7 O ~ O O M O 0 O O r 0 0 M IV M ~ N O M OV O 00 OM N N A Q I~ O M f0 0 0 0 00 0 ~~., M 0 00 N h O M 0 0 r N r M M 0 V O 0 CA f~ N O a O V I~ O O 00 (D 1~ (0 N V~ f0 N M N O O h 0 M 0 10 N ~ Q1 f0 O OO ~ ~ W ~ 10 M 01 n V' O a0 00 .O C ,~ 01 3 O1 W O 0 '~Y N ~ M 0 0 H O M 00 ~ O 10 O V' V V' M r O ~ N ~ h N O CA 00 t~ ~ M I~ N W Q1 10 N V' N O t0 O O N a1 f0 N O M O O I~ ' ' o O h 0 N 07 ~ N N f0 00 0 10 0) C p M N LL7 N t0 l0 v E r Q f M O / CA ~ M N 0 1n r h M O 0 CA M 01 M D t~ rj 01 O W M ao W M N O 40 f0 O O O N O 10 O ~ f0 I~ N ao V 00 r0 W h O M l7 N M O M M O M N 01 Oj f0 N V N ~ M r O N O C~ N 0 0 0 0 0 ~ G N V r 0 cO O O O G O G M O 0 0 0 r 0 0 ~ 0 OND N N OV V ~ M V N O 0 0 M N (0 10 h h W 0 00 10 f0 h O1 M O 10 M m N V M M 0 0 N M 0 0 h 01 10 0 OD to O 01 O N O ~ O O W (O N O N N O M 10 0/ f0 00 M O N 01 O 0) M N N N M 0 M N V O h ~ f~ N N N ~ ' C W C 0 n 0 f0 f0 M ~ 0 O 0 10 ((~~ 1~ N 00 (O 0 Q1 N 1[1 ao O f~ M 0 tF (O N ~ ~ W r O O M aT O M h O h 0 O r 01 V l1W M lL M f0 er 0 N 0 M 0 M W ~ M O ~ (O ~ h 0 M O 01 O O W O 0 ^ 0 M h 0 O 10 M I~ N 7 h N 0 ~ 0 ~ Q t E O U v~ 0 0 ~ X ~ p ~ OD 0 O 0 W E M~ ^ N O 0 0 h r f0 W O N ~ M N f 0 1~ f 0 1~ 0 0 0 0 0 0 N 0 ao 1~ 0 0 0 0 ~' h h ao 'Q p O 0 ~ ~ 0 ~ 0 M y 9 ~ N (+7 ~ N r M G r N M 0 fV N O 0 r O M f0 fV W 01 C G O O N O~ C r N M OC O M M M O 0 Q CA u0 f0 00 f0 M N f0 W 00 ~ (O h O N 0 n QI M N M V O M I~ O 00 N T (0 0 h W 10 00 00 I~ W O N N M V N N M (O M 0 N W 0 01 ~ M O h O 10 01 N ~ M N 0 01 N OD M ~ O 0 O h N OD 40 d ~0±1 M 7 0~ N 0 O M O N M 10 N M W 00 f0 ~ O n O O N O 100 1~ 0 0 O M V M O ~~ 01 a ah~- O M N M O O N O n ~ O N 001 n h 10 O n N hV N N 0 M O O n f0 M OD ~ ~ N 0 10 0 N ~ Q~ M cNp Ohj ~ t0fi O O M rhj N 0 ~ V' M O ~ O N~ N p N 0 0 0 0 Vh,' O N O~ O N ~ N n ~ O N ~ ~ f00 M OV V' N O (M O r N M 0 0 0 C r O M 0 (V d) 0 0 0 CJ r G~ 0 0 0 0 r r O r G r N M l7 T M _U ~„~ O 0 V W 00 0 V 0 M 0 10 0 ~ ~' O 0) OD N I~ T 00 ~ M 00 O W ~ (O 10 h M 00 W M ~ 0 O V' D1 O N 01 f~ N O M V O to O D) p h O 'V' 00 M 10 O 00 O 01 I~ lh h M O 10 V 00 D1 h M N h O O 0 N d' M 0 0 V' 00 U1 V' O N M Q) N r 1C1 ~ O M t0 h O d - C O h N 0 N h ~ 0 ~ O O 10 ~ W d' 0 O Uj t~ 10 a0 h M ~ W W h W O) N f0 M W ~ N 0 10 N N 0 ~ N M N O U v L~ ' ~~ ~"~ 0 0 M W ~ ~ I~ O N O O O N~ M B C ~ (~ O O O O W ( 9 ~ ~ ~ n ~ rj N O O O 1 W O ~ N ~ 0 <O 0 0 f0 f0 0 O G O O O N N O N O O N sf O~ 0 0 O O~ 0 00 O O ~ 01 r O O 0 0 D M OV N M ~ M N C 0 0 M N 00 O M N 0 O 0 lrl Qi ,a N ~ N ~ ~ r N M r N r r O r N~ r r M O ~'' t' Q h y 0 M 0 00 0 0 0 OD OO ~ M f0 0 N f~ CA M OJ 00 r r M M 0 M V Q1 0 D1 h N V' V' h Q1 0 OD (O h n I (O N <t 0 10 M N 0 0 I~ 0 M 7 0 ~ N 10 ~ W f0 0 00 10 ~ 0) N ~ t0 0 M 01 O h O '7 0 M 06 00 10 O ~ O sr M OO O M 0 V N N 0 n ~ 10 M r W n N 0 O O 0 M ~ M h N N M 0 O 0 N N N N 0 0 0 0 N^ M h 0 O h 0 N o ~ N O M N N C r d ~ ~ E r f0 CA M 01 M ~ O D 10 r M 0 0 O i O M M 0 ~ i 0 O i 0 m T N O 0 0 0 0 0 ' V' (0 N ao V 0 O 'a 0 0 i 10 M M M M O N M N O I ~ f0 p N Q v N ~ M r O N G O r N 0 0 0 G O O ~ O N V ~- CJ ~ G O O O O C M O 0 0 0 ~ 0 0 ~ 0 OND _ N N OV 7 7 (j v ~ N h' ~ 0.1 M N 01 (0 O M N 0 ~ h h O 00 00 10 (O I~ d) M W O M 01 N V M 10 O OO N W 0 t0 h W 10 00 00 N O O O N O V O N M f0 N O N N O M N p 0) 0 10 O N W D1 0 M N N N rn 0 M N ~ O h d' h N N 10 ~ 01 (O M N h W 0 O h V •f Q1 ~ V ~ h 0 01 f0 M M M (0 O W O N tF ^ p LL t E O 000 ' ' h ~ R OND O o h ^ O W ~ 6hi ~ O O ~ I~ M (MO 1 fM0 0 0 O O 'ct ~ 0 M 0 Vl O N 0 I~ 00 00 0 M 00 ~ O N N ~ M ~. - 61 3 U ~+ r N d M ~ ~ ~ N O r O M O G M rj r N N M O O 1~ N r OV 0 O c0 ~ r O N~ M 0 N CV ~ 01 n O1 G 0 G 0 O 0 O 0 LV O~ O O r N 0 V M ~ 00 h O ~ M O r 0 0 M M ~"~ ~ O Q 0 N N 0 0 0 M N (0 01 0 f~ f~ f0 f~ 00 4'1 0 h 0/ M N M V O M I~ O 00 N Q) f0 ' ' 0 h Q7 M OO OO I~ d) O N N M ~ N N M 0 M 0 N d) 0 0 V M 01 f~ O 10 ~ W N d. M N 10 D1 N 00 M 0 ~ O (O O N h N 10 0 10 N '~' a M fj' ~ 10 U 1~ O 10 (O 00 O M 'R O N M 0 10 N N M ~ 00 00 (O 0 O ~ O h 0 h 0 O O N N O 0 N 1~ 0 N O O 01 O M V M M h O ~ M f~ 1f1 O 'V' 1~ O W M N N (O O O 40 N O O h O 10 O N N N Of h h N 'Q I~ O I~ N h V N 0 h M 0 O p 0 N 1~ 0 h M 0 M N V' (0 O O O r 10 h 0 J Q• E M 0 Oj N LL ') O O M ~, j N O ~ ~ M O ~ O N ~ N ~ ~ O O O O ~ O N O H O N ~ N r ~ O N ~ ~ ( 0 M N ~ N O to O r N M O O G 0 r O M 0 CV D) O O O O r C~ C G O O r r O r O r N M ri O ~ ~a g a a a a g aa a ¢ a a a ¢ a a ¢a ¢ g g a a a g a ¢¢ ¢a a g a a a a g a a a ¢ 7 Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z N ~ y a J m U y C a ~ ~ C N C .X ~ a y ' E ~ U - C N ~ p O) E y E - 0) O j O tLj C C 01 N E ~ O •- N I- C L N OJ Q) E S T L C D c ~.m.. C ~ W O __ p O C C L 0 •`O y N 01 C O C ;O O Z V C_ U 01 0 E ~ -O W E L O T 7 '- n O C O E ~ O E E ~ O O ~ ~ ~ 3 V y U N Z' y O U ~ L [1 m = C E 7 01 > pCj > L O L j, t C ._ ' E E y > L C 0) ` C o E O 'O l0 N C O L O Q O a O t O O E 0 - O U N T U ~ , L O ~ t O L 9 U - V y ._ Q U 1 O 'O c C W . .. d w U O 01 J E•- Z w ~ Q N o 'O a/ y m 0 t d C 0) _ U O I- N X o U •- L +-' Ol U ~„ N LL V a Q m °° V C o U U o U V U d p Q o~ 0 - ^ W = ~ ~ a cLi c o - ~ ~ ~' 0 o y . o V O (0 M r U M X N C C O Q ~ U , V M _ O N = a ~ '° Ol r F- N E >. O a U ~ TDS Site Specific Standard Implementation (effective June 16, 2004) ADW AWW 7Q10 1Q10 Background TDS Mixing Zone (0-1) ZI D (0-1) TDS WLA DR: Acute WET DR: Chronic WET 9.144 mgd 14.146 cfs 13.486 mgd 20.863 cfs 9723 cfs 9018 300 mg/I 0.25 0.025 Avg. Conc. Max Conc. Avg. Mass Max. Mass (mg/I) (mg/I) (Ib/day) (Ib/day) 5.9 % effluent 94.1 % receiving water 0.6 % effluent 99.4 % receiving water Chloride WET Test Trigger Calcualtion ADW 9.144 mgd 14.146 cfs AWW 13.486 mgd 20.863 cfs 7Q10 9723 cfs 1Q10 9018 Background Chloride 30 mg/I Mixing Zone (0-1) 0.25 ZI D(0-1) 0.025 CI WLA Avg. Conc. Max Conc. Avg. Mass Max. Mass (mg/I) (mg/I) (Ib/day) (Ib/day) DR: Acute WET 5.9 % effluent 94.1 % receiving water DR: Chronic WET 0.6 % effluent 99.4 % receiving water effluent % receiving water Iron Limits: Criterion= 1 mg/I Iron WLAs: Avg. Conc. Max. Conc. Avg. Mass Max. Mass (mg/I) (mg/I) (Ib/day) (Ib/day) 7.38 7.38 598.64 598.64 APPENDIX C PRESENT WORTH ANALYSIS City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Appendix C -Present Worth Analysis INTRODUCTION The costs of the alternatives presented in this facilities plan are based on total present worth. The present worth analysis was used for the purposes of comparing the monetary costs of the alternatives evaluated. The total present worth of an alternative is the amount of money needed now to build, operate, and maintain the system over a 20-year period. The procedure used for calculating the total present worth conforms to the guidelines prepared by the Iowa DNR and the U.S. EPA. BASIS OF COST ANALYSIS A. Discount Rate The discount rate used for all present worth calculations is 4.875 percent. This is the annual percentage rate at which future sums were discounted on a compounded basis to determine their present value. B. Construction Costs Construction cost data was obtained principally from Strand Associates files for similar projects. Equipment cost estimates were either obtained from our files for similar equipment or obtained I~ from equipment suppliers and were adjusted to reflect installed costs. All capital costs are based on fourth quarter 2007 dollars. C. Operation and Maintenance Costs Operation and maintenance costs were estimated by using unit costs and annual estimates for labor, power, chemicals, and supplies. These costs were based on prices currently paid by the treatment plant or on prices obtained from potential suppliers. The hourly labor rate (including benefits) was estimated at $40. Energy costs used in the analysis were $0.08 per kilowatt-hour for electricity and $1.00 per therm for natural gas. The chemical costs used were $0.057 per pound for sodium hypochlorite, $0.29 per pound for sodium bisulfite, and $120 per ton of lime. The annual maintenance costs for the processes evaluated were typically estimated at 2 percent of the equipment cost. The cost included to transport high purity oxygen to the WPCP was $110/ton plus $1,600/mo. lease fee for the HPO storage tanks. Biosolids disposal costs were estimated as follows: Alternative RM1: $30/ton for ash in landfill Alternative RM2: $30/ton for ash in landfill, $28/ton for biosolids land application 'i I Alternative RM3: $20/ton for biosolids land application + $17,000/mo. lease fee Alternative RM4: $20/ton for biosolids land application + $10,000/mo. lease fee JEK:pII\S:\@SAI\151-200\1541002\WrdlReport\AppendiceslAppendix C.Present Worth.doc\052208 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Appendix C -Present Worth Analysis Alternative RM5: $35/ton for biosolids hauling and composting fee (does not include potential credit for compost value) Alternative RM6: $20/ton for dried biosolids land application + $5,000/mo. lease fee Alternative RM7: $20/ton for dried biosolids land application + $7,000/mo. lease fee D. Professional Services and Contin ewes Professional services including engineering, legal, bond counsel, interest during construction, and contingencies were estimated to be 35 percent of the estimated construction cost. E. General Conditions General conditions including a bid bond, performance bond, payment bonds, and insurance costs were estimated to be 8 percent of the estimated construction cost. F. Total Present Worth Calculations The procedures for calculating total present worth are as follows: 1. Estimates were made of the total capital cost on a unit-by-unit basis including technical services and contingencies. 2. Estimates were made of the cost and timing of future capital expenditures (replacements) in terms of current costs. The present worth of expenditures was computed by multiplying them by the single-payment present worth factors for the appropriate time period. Time periods and single-payment present worth factors used are listed as follows: Time period (years) Present Worth Factor 5 0.7882 10 0.6213 15 0.4897 20 0.3860 3. The annual operation and maintenance expenditures were converted to a present worth for 20 years. The present worth factor for an annuity over 20 years is 12.5954. 4. The salvage value of capital costs at the end of the 20-year planning period was calculated by using straight-line depreciation. The salvage value at the end of the planning period was converted to present worth by multiplying it by the single- payment present worth factor of 0.3860. JEK:pII\S:\@SAI\151-200\154\002\Wrd\ReportlAppendicesWppendix C.Present Worth.doc\052208 City of Dubuque, Iowa Dubuque Water Pollution Control Plant Facilities Plan Appendix C -Present Worth Analysis 5. The total present worth was computed by subtracting the salvage value from the sum of the initial cost, present worth of future capital costs, and present worth of operation and maintenance costs. JEK:pII\S:\@SAI\151-200\154\002\Wrd\ReportlAppendicesWppendix C.Present Worth.doc\052208 ~J ~ APPENDIX D DETAILED OPINIONS OF COST FOR BIOLOGICAL TREATMENT ALTERNATIVES Dubuque WPCP Facilities Plan -Appendix D Alternative 61 HPO with Trucked-in Liquid Oxygen 20 year TPW Discount Rate 4.875% Initial .Future ITEM Capital Capital . Service Replacement 20 yr Salvage Salvage Cost Cost Life Cost (P.W.) Value Value (P.W.) Aeration Basin Structures $350,000 40 $0 $175,000 $67,500 Building Modifications $0 20 $0 $0 $0 VPSA/PSA $0 20 $0 $0 $0 Mixers $1,438,000 20 $0 $0 $0 Monitoring and Controls $547,000 $400,000 15 $195,900 $364,667 $140,800 Subtotal $2,335,000 Sitework $0 25 $0 $0 $0 Mechanical (18%) $420,000 25 $0 $84,000 $32,400 Electrical and Controls (15%) $350,000 20 $0 $0 $0 Subtotal $3,105,000 Contractors General Conditions @ 8% $248,000 Construction Costs $3,353,000 Contingencies and Technical Services @ 35% $1,174,000 Total Capital Costs $4,527,000 $195,900 $623,667 $240,700 Present Worth $4,527,000 $196,000 $241,000 Estimated Annual O&M Costs Relative Labor ($40/hr) $83,000 Maintenance (2% of Equipment) $40,000 Liquid Oxygen (12 ton/day @ $110/ton) $501,000. Power ($0.08/kWH). $136,000 Total $760,000 Present Worth of O&M $9,572,000 ~ Summary of Present Worth- Costs Capital Cost $4,527,000 Replacement $196,000 O&M Cost $9,572,000 Salvage Value ($241,000) TOTAL PRESENT WORTH $14,054,000 includes $1600/mo rental cost for LOX storage/evap. Notes: No new structures. Dubuque WPCP Facilities Plan -Appendix D Alternative 62a HPO with On-Site V/PSA (City Owned) 20 year TPW Discount Rate 4.875% Initial Future ITEM Capital Capital Service Replacement 20 yr Salvage Salvage Cost Cost Life Cost (P.W.) Value Value (P.WJ Aeration Basin Structures $350,000 40 $0 $175,000 $67,500 Building Modifications $100,000 20 $0 $0 $0 V/PSA $1,890,000 20 $0 $0 $0 Mixers $1,438,000 20 $0 $0 $0 Monitoring and Controls $547,000 $400,000 15 $195,900 $364,667 $140,800 Subtotal $4,325,000 Sitework $0 25 $0 $0 $0 Mechanical (18%) $779,000 25 $0 $155,800 $60,100 Electrical and Controls (15%) $649,000 20 $0 $0 $0 Subtotal $5,753,000 Contractors General Conditions @ 8% $460,000 Construction Costs $6,213,000 Contingencies and Technical Services @ 35% $2,175,000 Total Capital Costs $8,388,000 $195,900 $695,467 $268,400. Present Worth ' Estimafed Annual O&M Costs Relative Labor ($40/hr) $104,000 Maintenance (2% of Equipment) $78,000 Liquid Oxygen ($110/ton) $19,000 Power ($0.08/kWH) $251,000 i Total $452,000 Present Worth of O&M $5,693,000 Summary of Presenf Worth Costs Capital Cost $8,388,000 .Replacement $196,000 O&M Cost $5,693,000 Salvage Value ($268,000) TOTAL PRESENT WORTH $14,009,000 $8,388,000 $196,000 $268,000 includes $1600/mo rental cost for LOX storage/evap. Notes: No new structures. Dubuque WPCP Facilities Plan -Appendix D Alternative B2b HPO with On-Site VPSA (Leased) 20 year TPW Initial Future -ITEM Capital Capital Service Replacement 20 yr Salvage Salvage Cost Cost Life Cost (P.W.) Value Value (P.W.) Aeration Basin Structures $350,000 40 $0 $175,000 $67,500 Building Modifications $100,000 20 $0 $0 $0 V/PSA (leased) $0 20 $0 $0 $0 Mixers $1,438,000 20 $0 $0 $0 Monitoring and Controls $547,000 $400,000 15 $195,900 $364,667 $140,800 Subtotal $2,435,000 Discount Rate 4.875% Sitework $0 25 $0 $0 $0 Mechanical (same as Alt. B2a) $779,000 25 $0 $155,800 $60,100 Electrical and Controls (same as Alt. B2a) $649,000 20 $0 $0 $0 Subtotal $3,863,000 Contractors General Conditions (same as Alt. B2t $460,000 Construction Costs $4,323,000 Contingencies and Technical Services (same as ~ $2,175,000 Total Capital Costs $6,498,000 $195,900 $695,467 $268,400 Present Worth $6,498,000 $196,000 $268,000 Estimated Annual O&M-Costs Relative Labor ($40/hr) . $42,000 Maintenance (2% of Equipment) $40,000 Lease Fee (own and operate) $325,200 Power ($0.08/kWH) $251,000 Total $658,000 Present Worth of O&M $8,288,000 includes $1600/mo rental cost for LOX storage/evap. Summary of Present Worth Costs Capital Cost $6,498,000 Replacement $196,000 O&M Cost $8,288,000 Salvage Value ($268,000) TOTAL PRESENT WORTH $14,714,000 Notes: No new structures. Dubuque WPCP Facilities Plan -Appendix D Alternative B3 Air Activated Sludge Discount Rate 4.875% 20 year TPW Initial Future ITEM Capital Capital Service Replacement 20 yr Salvage Salvage Cost Cost Life Cost (P.W.) Value Value (P.W.) Aeration-Basin Structures (incl. demolition) $ 5,175,000 40 $0 $2,587,500 $998,700 Building Modifications $100,000 20 $0 $0 $0 Aeration Blowers $1,331,000 20 $0 $0 $0 Fine Bubble Diffusers & Mixers $695,000 $695,000 10 $431,800 $0 $0 Monitoring and Controls $100,000 $100,000 15 $49,000 $66,667 $25,700 Subtotal $7,401,000 Sitework (5%) $370,000 25 $0 $74,000 $28,600 Mechanical (15%) $1,110,000 25 $0 $222,000 $85,700 Electrical and Controls (15%) $1,110,000 20 $0 $0 $0 Subtotal $9,991,000 Contractors General Conditions @ 8% $799,000 Construction Costs $10,790,000 Contingencies and Technical Services @ 35% $3,777,000 Total Capital Costs. $14,567,000 $480,800 $2,950,167 $1,138,700, Present Worth $14,567,000 $481,000 $1,139,000 Estimated Annual O&M Costs Relative Labor ($40/hr) $83,000 Maintenance (2% of Equipment) $43,000 Liquid Oxygen ($110/ton) $0 Power ($0.08/kWH) $225,000 -Total $351,000 Present Worth of O&M $4,421,000 Summary of Present Worth Costs Capital Cost $14,567,000 Replacement $481,000 O&M Cost $4,421,000 Salvage Value ($1,139,000) TOTAL PRESENT WORTH $18,330,000 Dubuque WPCP Facilities Plan -Appendix D Alternative B4 IFAS/MBBR Air Activated Sludge Discount Rate 4.875% 20 year TPW ITEM Initial Capital Cost Future Capital Cost Service Life Replacement 20 yr Salvage Salvage Cost (P.W.) Value Value (P.W.) MBBR Basins $ 1,086,750 40 $0 $543,375 $209,700 HPO Basin Modifications $300,000 40 $0 $150,000 $57,900 Building Modifications $100,000 20 $0 $0 $0 Aeration Blowers $1,331,000 20 $0 $0 $0 Fine Bubble Diffusers (existing) $216,000 $216,000 10 $134,200 $0 $0 MBBR Media and Diffusion Equipment $3,960,000 $3,960,000 15 $1,939,20b $2,640,000 $1,019,000 Monitoring and Controls $100,000 $100,000 15 $49,000 $66,667 $25,700 Subtotal $7,093,750 Sitework (5%) $355,000 25 $0 $71,000 $27,400 Mechanical (15%) . $1,064,000 25 $0 $212,800 $82,100 Electrical and Controls (15%) $1,064,000 20 $0 $0 $0 Subtotal $9,576,750 Contractors General Conditions @ 8% $766,000 Construction Costs $10,342,750 Contingencies and Technical Services @ 35% $3;620,000 Total Capital Costs $13,962,750 $2,122,400 $3,683,842 $1,421,800 Present Worth $13,963,000 $2,122,000 $1,422,000 Estimated.Annual O&M Costs Relative Labor ($40/hr) $83,000 Maintenance (2% of Equipment) $57,000 Liquid Oxygen ,($110/ton) $0 Power ($0.08/kWH) $225,000 Total- $365,000 Present Worth of O&M $4,597,000 Summary of Present Worth Costs Capital Cost $13,963,000 Replacement $2,122,000 O&M Cost. $4,597,000 Salvage Value ($1,422,000) TOTAL PRESENT WORTH $19,260,000 APPENDIX E DETAILED OPINIONS OF COST FOR DISINFECTION ALTERNATIVES Dubuque WPCP_ Facilities Plan -Appendix E Alternative D1 Gaseous Chorination and Liquid Dechlorination Discount Rate 4.875% 20 year TPW Initial Future ITEM Capital Capital Service Replacement 20 yr Salvage Salvage Cost Cost Life Cost (P.W.) Value Value (P.W.) Structural $20,000 40 $0 $10,000 $3,900 Chemical Storage $0 20 $0 $0 $0 Chlorination Equipment $320,000 $237,000 15 $116,100 $213,333 $82,300 Subtotal $340,000 Sitework (7%) $24,000 25 $0 $4,800 $1,900 Mechanical (22%) $75,000 25 $0 $15,000 $5,800 20 $0 $0 $0 Electrical- and Controls (20%) $68,000 20 $0 $0 $0 Subtotal $507,000 Contractors General Conditions @ 8% $41,000 Construction Costs $548,000 Contingencies and Technical Services @ 35% $192,000 Total Capital Costs $740,000 $116,100 $243,133 $93,900 Present Worth $740,000 $116,000 $94,000 Estimated Annual O&M Costs Labor $15,000 Chemicals $33,000 Maintenance $13,600 Power $700 Total $62,000 Present Worth of O&M $781,000 Summary of Present Worth Costs Capital Cost $740,000 Replacement $116,000 O&M Cost $781,000 Salvage Value ($94,000) TOTAL PRESENT WORTH $1,543,000 Notes: No new structures. Dubuque WPCP Facilities Plan -Appendix E Alternative D2 Liquid Chlorination - Hypochlorite Delivered Discount Rate 4.875% 20 year TPW Initial Future ITEM Capital Capital Service Replacement 20 yr Salvage Salvage Cost Cost Life Cost (P.W.) Value Value (P.W.) Structural $125,000 40 $0 $62,500 $24,100 Chemical Storage (incl in equip) $68,000 20 $0 $0 $0 Chlorination Equipment .$103,000 $76,000 15 $37,200 $68,667 $26,500 Subtotal $296,000 Sitework (5%) $15,000 25 $0 $3,000 $1,200 Mechanical (18%) $53,000 25 $0 $10,600 $4,100 Electrical and Controls (20%) $59,000 20 $0 $0 $0 Subtotal $423,000 Contractors General Conditions @ 8% $34,000 Construction Costs $457,000 Contingencies and Technical Services @ 35% $160,000 Total Capital Costs $617,000 $37,200 $144,767 $55,900 Present Worth $617,000 $37,000 $56,000 Estimated Annual O&M Costs Labor $15,000 Chemicals $35,000 Maintenance $7,000 Power $700 Total $58,000 Present Worth of O&M $731,000 Summary of Present Worth Cosfs Capital Cost $617,000 Replacement $37,000 O&M Cost $731,000 Salvage Value ($56,000) TOTAL PRESENT WORTH $1,329,000 Notes: No new building or CCT needed. Dubuque WPCP Facilities Plan -Appendix E Alternative D3 Omsite Hypochlorite Generation 20 year TPW Discount Rate 4.875% Initial Future ITEM Capital Capital Service Replacement 20 yr Salvage Salvage Cost Cost Life Cost (P.W.) Value Value (P.W.) Structural $75,000 40 $0 $37,500 $14,500 Chemical Storage $120,000 20 $0 $0 $0 Chlorination Equipment $539,000 $399,000 15 $195,400 $359,333 $138,700 Subtotal $734,000 Sitework (5%) $37,000 25 $0 $7,400 $2,900 Mechanical (18%) $132,000 25 $0 $26,400 $10,200 Electrical and Controls (20%) Subtotal Contractors General Conditions @ 8% Construction Costs Contingencies and Technical Services @ 35% Total Capital Costs Present Worth 20 $0 $0 $0 $147,000 20 $0 $0 $0 $1,050,000 $84,000 $1,134,000 $397,000 $1,531,000 $195,400 $430,633 $166,300 $1,531,000 $195,000 $166,000 Estimated Annual O$M Costs Labor $20,000 Chemicals $18,000 Maintenance $22,000 Power $8,000 Total $68,000 Present Worth of O&M $856,000 Summary of Present Worth Costs Capital Cost $1,531,000 Replacement $195,000 O&M Cost $856,000 Salvage Value. ($166,000) TOTAL PRESENT WORTH $2,416,000 Notes: No-new structures. Dubuque WPCP Facilities Plan -Appendix E Alternative D4 Ozone 20 year TPW Discount Rate 4.875% Initial Future ITEM Capital Capital Service Replacement 20 yr Salvage Salvage Cost Cost Life Cost (P.W.) Value Value (P.W.) Structural $75,000 40 $0 $37,500 $14,500 Chemical Storage $0 20 $0 $0 $0 Ozone Equipment $1,781,000 $1,319,000 15 $645,900 $1,187,333 $458,300 Subtotal $1,856,000 Sitework (5%) $93,000 25 $0 $18,600 $7,200 Mechanical (18%) $334,000 25 $0 $66,800 $25,800 Electrical and Controls (20%) Subtotal Contractors General Conditions @ 8% Construction Costs Contingencies and Technical Services @ 35% Total Capital Costs Present Worth Estimated Annual OSM Costs 20 $0 $0 $0 $371,000 20 $0 $0 $0 $2,654,000 $212,000 $2,866,000 $1,003,000 $3,869,000 $645,900 $1,310,233 $505,800 $3;869,000 $646,000 $506,000 Labor $20,000 Chemicals (Bulk Oxygen @ $110/ton) $6,000 Maintenance $36,000. Power $53,000 Total $115,000 Present Worth of O&M $1,448,000 Summary of Present Worth Costs Capital Cost $3,869,000 Replacement $646,000 O&M Cost $1,448,000 Salvage Value ($506,000) TOTAL.PRESENT WORTH $5,457,000 Notes: No new structures. Includes credit for dechlorination system chemical use. Dubuque WPCP Facilities Plan -Appendix E Alternative D5 UV Disinfection 20 year TPW Discount Rate 4.875% Initial Future ITEM Capital Capital Service Replacement 20 yr Salvage Salvage Cost Cost Life Cost (P.WJ Value Value (P.WJ UV Equipment (incl prefab control bldg) $821,000 $583,000 15 $285,500 $547,333 $211,300 Structural/Demo (modify CCT for UV) $80,000 40 $0 $40,000 $15,400 Subtotal $901,000 Sitework (5%) $45,000 25 $0 $9,000 $3,500 Mechanical (12%) $108,000 25 $0 $21,600 $8,300 Electrical and Controls (20%) $180,000 20 $0 $0 $0 ' Subtotal $1,234,000 Contractors General Conditions @ 8% $99,000 Construction Costs $1,333,000 Contingencies and Technical Services @ 35% $467,000 Total Capital Costs $1,800,000 $285,500 $617,933 $238,500 Present Worth $1,800,000 $286,000 $239,000 Estimated Annual O&M Costs Labor $15,000 ~I Chemicals $1,000 Lamp Replacement $18,200 Power $12,000 Total $46,200 Present Worth of 0&M $582,000 Summary of Present Worth Costs I, Capital Cost $1,800,000 Replacement $286,000 O&M Cost $582,000 Salvage Value ($239,000) TOTAL PRESENT WORTH $2,429,000 Notes: APPENDIX F DETAILED OPINIONS OF COST FOR RESIDUALS MANAGEMENT ALTERNATIVES Dubuque WPCP Facilities Pian -Appendix F Alternative RM1a Refurbish Both Existing Incinerators Discount Rate 4.875% 20 year Opinion of Total Present Worth Initial Future ITEM Capital Capital Service Replacement 20 yr Salvage Salvage Cost Cost Life Cost(P.WJ Value Value(P.WJ Demolition and Building Modifications $500,000 20 $0 $0 $0 Building Addition (2,000 sq ft) $600,000 20 $0 $0 $0 North Incinerator Rehab $3,000,000 20 $0 $0 $0 North Incinerator Equipment and Controls $2,160,000 $2,160,000 15 $1,057,700 $1,440,000 $555,800 South Incinerator Rehab $3,000,000 20 $0 $0 $0 South Incinerator Equipment and Controls $2,160,000 $2,160,000 15 $1,057,700 $1,440,000 $555,800 WAS Aeration Blowers (3) $202,500 20 $0 $0 $0 WAS Aeration Diffusers $50,000 $25,000 10 $15,500 $0 $0 ~ Sludge Blending Tank (20,000 gal) $35,000 20 $0 $0 $0 ' Sludge Blending Tank Mixer and Controls $10,000 $10,000 15 $4,900 $6,667 $2,600 Sludge Flow Meters (3) $20,000 $20,000 15 $9,800 $13,333. $5,100 Scum Concentrator $210,000 $210,000 15 $102,800 $140,000 $54,000 Centrifuges Feed Pumps (3) $101,250 $101,250 15 $49,600 $67,500 $26,100 ~i Centrifuges (2) $783,000 $391,500 15 $191,700 $522,000 $201,500 Centrifuge Rehab (1) and Backdrive $80,000 $80,000 15 $39,200 $53,333 $20,600 Cake Screw Conveyors $150,000 $150,000 15 $73,500 $100,000 $38,600 High-Solids Pump Rehab $145,800 $145,800 15 $71,400 $97,200 $37,500 New High-Solids Pump $364,500 $145,800 15 $71,400 $243,000 $93,800 Subtotal $13,572,050 Sitework (5% of Building Addition) $30,000 25 $0 $6,000 $2,300 ~ Mechanical (20%) $2,714,000 25 $0 $542,800 $209,500 HVAC (3%) $407,000 I Electrical and Controls (15%) $2,036,000 20 $0 $0 $0 Subtotal $18,759,050 Contractors General Conditions (cD 8% $1,501,000 Construction Costs $20,260,050 Contingencies and Technical Services @ 35% $7,091,000 Total Capital Costs $27,351,050 $2,745,200 $4,671,833 $1,803,200 Present Worth $27,351,000 $2,745,000 $1,803,000 I Estimated Annual O&M Costs (30,000 lbs/day,• dry basis) Relative Labor ($40/hr) $332,800 Maintenance (^2% of Equipment) $129,000 ', Oxygen $160,600 Additional 4 tons O2/day at future average (longer SRT) Solids Disposal $21,353 _ 87°/u solids destruction; $30/ton disposal Fuel $109,500 _ 100 gal/day assumed (start-up); $3.50/gal Power ($0.08/kWH) $129,147 Assumed ~ 6 days/week average; only power related to Incinerator is included Total $882,000 Present Worth of O8M ~ $11,109,000 , I Summary of Present Worth Costs Capital Cost $27,351,000 Replacement $2,745,000 O&M Cost $11,109,000 Salvage Value ($1,803,000) TOTAL PRESENT WORTH $39,402,000 Dubuque WPCP Facilities Plan -Appendix F Alternative RM1b Refurbish One Incinerator; Retain Other Incinerator for Standby Discount Rate 4.875% 20 year TPW i ! Initial Future ITEM Capital Capital Service Replacement 20 yr Salvage Salvage ~ Cost Cost Life Cost (P.WJ Value Value (P.W.) Demolition and Building Modifications $500,000 20 $0 $0 $0 Building Addition (2,000 sq ft) North Incinerator Rehab $3,000,000 20 $0 $0 $0 North Incinerator.Equipmentavd Controls- $2,160,000 $2,160,000 15 $1,057,700 $1,440,000 $555,800 South Incinerator Rehab South Incinerator Equipment and Controls $2,160,000 15 $1,057,700 $0 $0 ~' WAS Aeration Blowers (3) $202,500 20 $0 $0 $0 WAS Aeration Diffusers $50,000 $25,000 10 $15,500 $0 $0 Sludge Blending Tank (20,000 gal) $35,000 20 $0 $0 $0 Sludge Blending Tank Mixer and Controls $10,000 $10,000 15 $4,900 $6,667 $2,600 Sludge Flow Meters (3) $20,000 $20,000 15 $9,800 $13,333 $5,100 Scum Concentrator $210,000 $210,000 . 15 $102,800 $140,000 $54,000 Centrifuges Feed Pumps (3) $101,250 $101,250 15 $49,600 $67,500 $26,100 Centrifuges (2) $783,000 $391,500 15 $191,700 $522,000 $201,500 Centrifuge.Rehab (1) and Backdrive $80,000 $80,000 15 $39,200 $53,333 $20,600 Cake Screw Conveyors $150,000 $150,000 15 $73,500 $100,000 $38,600 High-Solids Pump Rehab $145,800 $145,800 15 $71,400 $97,200 $37,500 New High-Solids Pump $364,500 $145,800 15 $71,400 $243,000 $93,800 Subtotal $7,812,050 I' Sitework (5% of Building Addition) $0 25 $0 $0 $0 Mechanical (20%) $1,562,000 25 $0 $312,400 $120,600 ' HVAC (3%) $234,000 Electrical and Controls (15%) $1,172,000 20 $0 $0 $0 Subtotal $10,780,050 Contractors General Conditions @ 8% $862,000 Construction Costs $11,642,050 Contingencies and Technical Services @ 35% $4,075;000 Total Capital Costs $15,717,050 $2,745,200 $2,995,433 $1,156,200 Present Worth $15,717,000 $2,745,000 $1,156,000 Estimated Annual O&M Costs (30,000 Ibs/day; dry basis) Relative Labor ($40/hr) $366,080 10% greater than Alt. RM1 a Maintenance (~2% of Equipment) $148,350 15% greater than Alt. RM1 a Oxygen $160,600 Additional 4 tons 02/day at future average (longer SRT) Solids Disposal $21,353 ~ 87% solids destruction; $3 0/ton disposal Fuel $125,925 15% greater than Alt. RM1a Power ($0.08/kWH) $135,605 5% greater than Alt. RM1 a Total $958,000 Present Worth of O&M $12;066,000 Summary of Present Worth Costs Capital Cost $15,717,000 ' ' Replacement $2,745,000 i O&M Cost $12,066;000 Salvage Value ($1,156,000) TOTAL PRESENT WORTH $29,372,000 Dubuque WPCP Facilities Plan -Appendix F_ Alternative RM2a One Refurbished Incinerator and Back-Up Lime Stabilization Dismount Rate 4.875% 20 year TPW Initial Future ITEM Capital Capital Service Replacement 20yrSalvege SaNage Cost Cost Life Cost (P.W.) Value Value (P. W.) Demolition and Building Modifications $500,000 20 $0 $0 $0 New Incinerator $3,000,000 20 $0 $0 $0 EqulpmentandControls $2,180,000 $2,180,000 15 $1,057,700 $1,440,000 $555,800 Lima Stabilization System $650,000 20 $0 $0 ~ $0 Equipment $420,000 $420,000 15 $205,700 $280,000 $108,100 Odor and Dust Control $270,000 $270,000 15 $132,200 $180,000 $89,500 Blosolids Storege (5,000 sq. ft) $250,000 20 $0 $0 $0 WAS Aeretion Blowers (3) $202,500 20 $0 $0 $0 WAS Aeretion Diffusers $50,000 $25,000 10 $15,500 $0 $0 Sludge Blending Tank (20,000 gal) $35,000 20 $0 $0 $0 Sludge Blending Tank Mixer and Controls $10,000 570,000 15 $4,900 $8,867 $2,600 Sludge Flow Meters (3) $20,000 $20,000 15 $9,800 $13,333 $5,100 Scum Concentrator $210,000 $210,000 15 $102,800 $140,000 $54,000 Centdfuges Feed Pumps (3) $107,250 $107,250 15 $49,600 $67,500 $28,100 Centrifuges (2) $783,000 $397,500 15 $797,700 $522,000 $201,500 Centrifuge Rehab (1) and Backdrive $80,000 $80,000 15 $38,200 $53,333 $20,800 Cake Screw Conveyors $150,000 $150,000 15 $73,500 $100,000 $38,800 HlghSolids Pump Rehab $145,800 $145,800. 15 $71,400 $97,200 $37,500 Subtotal $9,037,550 Sitework (5% of Building AddiBon) $12,500 25 $0 $2,500 $7,000 Mechanical (20%) $1,808,000 25 $0 $381,800 $139,60D HVAC (3%) $271,000 Electricel and Controls (155'0) - $1 356.000 20 $0 $0 $0 Subtotal $12,485,050 Contractors General Conditions @ 8% $999.000 ~ ConsWction Costs $13,404,050 Contingences and Technical Services (~ 35% $4.719.000 Total Capital Costs $18,203,050 $1;954,000 $3,264,133 $1,280,000 Present Worth ~ $18,203,000 51,954,000 EstlmatedAnnua1O8MCosfs(30,000/lu/day:dr Y6asls) llmonths 1 ont ota Relative Labor($40/hr) $0 $332,800 Maintenance (-2% of Equipment) $108,333 $9,667 5116,000 Oxygen; Llme; Acid $147,217 $38,836 $184,052 Solids Disposal $19,573 $58,280 $75,853 - Fuel $100,375 $100,375 Power($0.08/kWH) $118.385 $5.300 $123,895 Total $492,000 $108,000 $933,000 Present Worth of O8M ~ $11,751,000 Summary 01 Present Worth Costs Capital Cost $18,203,000 Replacement $1,954,000 OB,M Cost $11,751,000 Salvage Value ($1.260.000) TOTAL PRESENT WORTH $30,648,000 51,260,000 AddlOonal 4 tons O2/day; Ilme ~ 9.75 tons/day; acid (a) 9001bs/week $30Aon disposal for ash; S28lton for biosolids -100 gaVday assumed (start-up); 53.50/gal Assumed - e days/week average; only power related to incinerator Is included e Dubuque WPCP FacIIltles Plan -Appendix F Altemetlve RM2b One New Incinerator and Back-Up Ltme Stablllzation Discount Rate 4.875% zo year TPw Initial Future ITEM Capital Capital Service Replacement 20yrSeNageSalvege Cost Cost Life Cost (P.W.) Value Value (P.W) Demolition and Building Modifications $500,000 20 $0 $0 $0 New InGnerelor $9,840,000 20 $0 $0 $0 Equipment and Controls $3,000,000 $3,000,000 15 $1,4139,100 $2,000,000 $772,000 Lime Stabilization System $850,000 20 $0 $0 $0 Equipment $420,000 $420,000 15 $205,700 $260,000 $108,100 Odor and Dust Control $270,000 $270,000 15 $132,200 $100,000 $88,500 Biosolids Storage (5,000 sq. ft.) $250,000 20 $0 $0 $0 WAS Aeration Blowers (3) $202,500 20 $0 $0 $0 WASAeretionDiffusere $50,000 $25,000 10 $15,500 $0 $0 Sludge Blending Tank (20,000 gaQ $35,000 20 $0 $0 $0 Sludge Blending Tank Mixer and Controls $10,000 $10,000 15 $4,800 $6,867 $2,600 Sludge Flow Meters (3) $20,000 $20,000 15 $9,800 $13,333 $5,100 Scum Concentrator $210,000 $210,000 15 $102,800 $140,000 $54,000 Centrifuges Feed Pumps (3) $101,250 $101,250 15 $48,800 $87,500 $26,100 Centrifuges (2) $783,000 $391,500 15 $191,700 $522,000 $201,500 Centrifuge Rehab (1) and Backdrive $00,000 $80,000 15 $39,200 $53,333 $20,600 Cake Screw Conveyors $150,000 $150,000 15 $73,500 $100,000 $38,600 HighSollds Pump Rehab $145,800 $145,800 15 $71,400 $97,200 $37,500 Subtotal $18,717,550 Sitework (5% of Building Addition) $12,500 25 $0 $2,500 $1,000 Mechanical (20%) $3,344,000 25 $0 $888,800 $258,100 HVAC (3%) $502,000 - EleGriceland Controls (15%) $2 508 000 20 $0 $0 $0 Subtotal $23,084,050 Contractors General Conditions (aj 8% $1,847,000 ConsWCtion Costs $24,931,050 Contingencies and Technical Services (4135% $8 728 000 Total Capital Costs $33,657,050 $2,365,400 $4,131,333 $1,594,700 Present Worth 333,657,000 $2,365,000 $1,595,000 Estimated AnnualOBMCosts (30,000/bs/day; dry basis) 91 months ont otal Relative Labor ($40/hr) $0 $332,800 Maintenance (-2% of Equipment) $106,333 $9,867 $118,000 Oxygen, Lime; AGd $147,217 $38,836 ~ $184,052 Additional 4 tons O2/day; lime (aj 9.75 tons/day; acid (a; 9001bs/week Solids Disposal $19,573 $58,280 $75,853 - $30/ton disposal for ash; $28lton for biosolids Fuel $100,375 $100,375 -100 gaVday assumed (start-up); $3.50/gal Power ($0.08/kWH) $118,385 $5.300 $123,685 Assumed - 8 dayshveek average; only power related to incnerator Is included Total $492,000 $108,000 $933,000 Present Worth of O&M $11,751,000 Summary of Present Worth Costs Capital Cost $33,857,OD0 Replacement $2,385,000 O&M Cost $11,751,000 Salvage Value ($1,595,000) TOTAL PRESENT WORTH $46,178,000. Dubuque WPCP Facilities Plan -Appendix F Alternative RM3 Lime Stabilization with Agricultural Land Application Discount Rate 4.875°h 20 year TPW InlUal Future ITEM Capital Capital Service Replacement 20 yr Salvage Salvage Cost Cost Life Cost(P.W.) Value Value(P.W.) Demolition and Building Modifications $500,000 20 $0 $0 $0 20 $0 $0 $0 Lime Stabilization Systems $1,260,000 20 $0 $0 $0 Equipment $840,000 $840,000 15 $411,300 $560,000 $216,100 Odor and Dust Control $540,000 $540,000 15 $264,400 $360,000 $139,000 Blosolids Storage (15,000 sq. ft.) $750,000 20 $0 $0 $0 WAS Aeration Blowers (3) $202,500 20 $0 $0 $0 WAS Aeration Diffusers $50,000 $25,000 10 $15,500 $0 $0 Sludge Blending Tank (20,000 gal) $35,000 20 $0 $0 $0 Sludge Blending Tank Mixer and Controls $10,000 $10,000 15 $4,900 $6,887 $2,600 Sludge Flow Meters (3) $20,000 $20,000 15 $9,800 $13,333 $5,100 Centrifuges Feed Pumps (3) $101,250 $101,250 15 $49,600 $67,500 $26,100 Centrifuges (2) $783,000 $391,500 15 $191,700 $522,000 $201,500 Centrifuge Rehab (1) and Backdrive $80,000 $80,000 15 $39,200 $53,333 $20,600 Cake Screw Conveyors $150,000 $150,000 15 $73,500 $100,000 $38,600 Hlgh-Sollds Pump Rehab $145,800 $145,800 15 $71,400 $97,200 $37,500 Subtotal $5,467,550 Sitework (5°h of Building Addition) $37,500 25 $0 $7,500 $2,900 Mechanical (25%) $1,367,000 25 $0 $273,400 $105,500 HVAC (7%) $383,000 Electdcal and Controls (20°h) $1,094,000 20 $0 $0 $0 Subtotal $8,349,050 Contractors General Conditions (418°h $668,000 Construction Costs $9,017,050 Contingencies and Technical Services ~ 35°~ $3,156,000 Total Capital Costs $12,173,050 $1,131,300 $2,060,933 $795,500 Present Worth $12,173,000 Estimated Annual O8M Costs (30,0001bs/day; dry basis) Total Relative Labor ($40/hr) $332,800 Maintenance (-2°h of Equipment) $116,000 Lime, Acid, Odor Confrol $467,029 Sollds Disposal $693,100 Fuel $0 Power ($0.06/kWH) $63,600 Total $1,673,000 Present Worth of O&M $21,072,000 $1,131,000 $796,000 Additional 4 tons 02/day; lime (419.75 tons/day; acid ~ 900 Ibs/week $20Ron for biosollds+ 17,000/mo lease fee -100 gal/day assumed (start-up); $3.50/gal Assumed - 6 days/week average; only power related to incinerator is InGuded Summary of Present Worth Costs Capital Cost $12,173,000 Replacement $1,131,000 O&M Cost $21,072,000 Salvage Value ($796,000) TOTAL PRESENT WORTH $33,580,000 Dubuque WPCP Facilities Plan -Appendix F Alternative RM4 Anaerobic Digestion with Agricultural Land Application Discount Rate 4.875% 20 year TPW Initial Future ITEM Capital Capital Service Replacement 20 yr Salvage Salvage Cost Cost Life Cost (P.W.) Value Value (P.W.) ~ Sludge Processing Building Demolition and Modifications $500,000 20 $0 $0 $0 20 $0 $0 $0 Anaerobic Digestion Control Building (5,000 sq ft) $1,250,000 30 $0 $416,667 $160,800 Digestion Tanks (4) $2,983,000 40 $0 $1,491,500 $575,700 Covers $1,917,000 20 $0 $0 $0 Mixing Equipment (Pumps and Piping) $789,750 20 $0 $0 $0 Feed and Transfer Pumps (6) $162,000 $162,000 15 $79,300 $108,000 $41,700 Gas Safety Equipment $217,500 $217,500 15 $106,500 $145,000 $56,000 ' Boiler/Heat Exchangers/Recirc. Pumps $1,620,000 20 $0 $0 $0 Biosolids Storage (10,000 sq. ft.) $500,000 20 $0 $0 $0 WAS Aeration Blowers (3) $202,500 20 $0 $0 $0 WAS Aeration Diffusers $50,000 $25,000 10 $15,500 $0 $0 Sludge Blending Tank (20,000 gal) $35,000 20 $0 $0 $0 Sludge Blending Tank Mixer and Controls $10,000 $10,000 15 $4,900 $6,667 $2,600 Sludge Flow Meters (3) $20,000 $20,000 15 $9,800 $13,333 $5,100 Thickening Centrifuges (2) $378,000 $378,000 15 $785,100 $252,000 $97,300 TWAS Pumps (2) $54,000 $27,000 15 $13,200 $36,000 $13,900 Centrifuges Feed Pumps (3) $101,250 $101,250 15 $49,600 $67,500 $26,100 Centrifuges (2) $783,000 $391,500 15 $191,700 $522,000 $201,500 Centrifuge Rehab (1) and Backdrive $80,000 $80,000 15 $39,200 $53,333 $20,600 Cake Screw Conveyors $150,000 $150,000 15 $73,500 $100,000 $38,600 High-Solids Pump Rehab $145,800 $145,800 15 $71,400 $97,200 $37,500 Subtotal $11,948,800 Sitework (5% of Building Addition) $211,650 25 $0 $42,330 $16,300 Mechanical (25%) $2,987,000 25 $0 $597,400 $230,600 HVAC (7%) $836,000 Electrical and Controls (20%) $2,390,000 20 $0 $0 $0 Subtotal $18,373,450 Contractors General Conditions @ 8% $1,470,000 Construction Costs $19,843,450 Contingencies and Technical Services @ 35% $6,945,000 Total Capital Costs $26,788,450 $839,700 $3,948,930 $1,524,300 Present Worth $26,788,000 $840,000 $1,524,000 Estimated Annual O&M Costs (30,000 /bs/day; dry basis) Total Relative Labor ($40/hr) $291,200 Maintenance (^~2% of Equipment) $87,000 Chemicals, Additional 02 $30,000 for recycle BOD load Solids Disposal $327,652 ~ $20/ton for biosolids+ 10,000/mo lease fee Fuel $0 Power ($0.08/kWH) $54,894 Electrical Credit ($0.04/kWH) Total $791,000 Present Worth of O&M $9,963,000 Summary of Present Worth Costs Capital Cost $26,788,000 Replacement $840,000 O&M Cost $9,963,000 ~~ Salvage Value ($1,524,000) TOTALPRESENT WORTH $36,067,000 Dubuque WPCP Facilities Plan -Appendix F Alternative RM5 Anaerobic Digestion with Composting Diswunt Rate 4.875% 20 year TPW Initial Future ITEM Capital Capital Service Replacement 20 yr Salvage Salvage Cost Cost Life Cost (P.W.) Value Value (P. W.) Sludge Processing Building Demolition and Modifications $500,000 20 $0 $0 $0 Anaerobic Digestion Control Building (5,000 sq ft) $1,250,000 30 $0 $416,667 $160,800 Digestion Tanks (4) $2,983,000 40 $0 $1,491,500 $575,700 Covers $1,917,000 20 $0 $0 $0 Mixing Equipment (Pumps and Piping) $789,750 20 $0 $0 $0 Feed and Transfer Pumps (6) $162;000 $162,000 15 $79,300 $108,000 $41,700 Gas Safety Equipment $217,500 $217,500 15 $106,500 $145,000 $56,000 Boiler/Heat Exchangers/Recirc. Pumps $1,620,000 20 $0 $0 $0 _ Biosolids Storage (10,000 sq. ft.) $500,000 20 $0 $0 $0 WAS Aeration Blowers (3) $202,500 20 $0 $0 $0 WAS Aeration Diffusers $50,000 $25,000 10 $15,500 $0 $0 Sludge Blending Tank (20,000 gal) $35,000 20 $0 $0 $0 Sludge Blending Tank Mixer and Controls $10,000 $10,000 15 $4,900 $6,667 $2,600 Sludge Flow Meters (3) $20,000. $20,000 15 $9,800 $13,333 $5,100 Thickening Centrifuges (2) $378,000 $378,000 15 $185,100 $252,000 $97,300 TWAS Pumps (2) $54,000 $27,000 15 $13,200 $36,000 $13,900 Centrifuges Feed Pumps (3) $101,250 $101,250 15 $49,600 $67,500 $26,100 Centrifuges (2) $783,000 $391,500 15 $191,700 $522;000 $201,500 Centrifuge Rehab (1) and Backdrive $80,000 $80,000 15 $39,200 $53,333 $20,600 Cake Screw Conveyors $150,000 $150,000 15 $73,500 $100,000 $38,600 High-Solids Pump Rehab $145,800 $145,800 15 $71,400 $97,200 $37,500 Subtotal $11,948,800 Sitework (5% of Building Addition) $211,650 25 $0 $42,330 $16,300 Mechanical (25%) $2,987,000 25 $0 $597,400 $230,600 HVAC (7%) $836,000 Electrical and Controls (20%) $2,390,000 20 $0 $0 $0 Subtotal $18,373,450 Contractors General Conditions @ 8% $1,470,000 Construction Costs $19,843,450 Contingencies and Technical Services @ 35% $6,945,000 Total Capital Costs $26,788,450 $839,700 $3,948,930 $1,524,300 Present Worth $26,788,000 $840,000 $1,524,000 Estimated AnnualO&M Costs (30,0001bs/day;drybasis) Total Relative Labor ($40/hr) $291,200 Maintenance (-2% of Equipment) $87,000 Chemicals, Additional 02 $30,000 for recycle BOD load Solids Disposal $363,391 ~ $35/ton for biosolids Fuel ~ $0 Power ($0.08/kWH) $54,894 Electrical Credit ($0.04/kWH) Total $826,000 Present Worth of O&M $10,404,000 Summary of Present Worth Costs Capital Cost $26,788,000 Replacement $840,000 O&M Cost $10,404,000 Salvage Value ($1,524,000) TOTAL PRESENT WORTH $36,508,000 Dubuque WPCP Facilities Plan -Appendix F Alternative RM6 Anaerobic Digestion with Drying and Agricultural Land Application Discount Rate 4.875% 20 year TPW Initial Future ITEM Capital Capital Service Replacement 20 yr Salvage Salvage Cost Cost Life Cost (P.W.) Value Value (P.W.) Sludge Processing Building Demolition and Modifications $500,000 20 $0 $0 $0 20 $0 $0 $0 Anaerobic Digestion Control Building (5,000 sq ft) $1,250,000 30 $0 $416,667 $160,800 Digestion Tanks (4) $2,983,000 40 $0 $1,491,500 $575,700 Covers $1,917,000 20 $0 $0 $0 Mixing Equipment (Pumps and Piping) $789,750 20 $0 $0 $0 Feed and Transfer Pumps (6) $162,000 $162,000 15 $79,300 $108,000 $41,700 Gas Safety Equipment $217,500 $217,500 15 $106,500 $145,000 $56,000 Boiler/Heat Exchangers/Recirc. Pumps $1,620,000 20 $0 $0 $0 Biosolids Storage (5,000 sq. ft.) $250,000 20 $0 $0 $0 WAS Aeration Blowers (3) $202,500 20 $0 $0 $0 WAS Aeration Diffusers $50,000 $25,000 10 $15,500 $0 $0 Sludge Blending Tank (20,000 gal) $35,000 20 $0 $0 $0 Sludge Blending Tank Mixer and Conirois $10,000 $10,000 15 $4,900 $6,667 $2,600 Sludge Flow Meters (3) $20,000 $20,000 15 $9,800 $13,333 $5,100 Thickening Centrifuges (2) $378,000 $378,000 15 $185,100 $252,000 $97,300 TWAS Pumps (2) $54,000 $27,000 15 $13,200 $36,000 $13,900 Centrifuges Feed Pumps (3) $101,250 $101,250 15 $49,600 $67,500 $26,100 Centrifuges (2) $783,000 $391,500 15 $191,700 $522,000 $201,500 Centrifuge Rehab.(1) and Backdrive $80,000 $80,000 15 $39,200 $53,333 $20,600 Cake Screw Conveyors High-Solids Pump Rehab Drying Equipment (2 Units) Odor and Dust Control Subtotal Sitework (5% of Building Addition) ~ Mechanical (20%) ~ HVAC (7"/0) Electricai and Controls (20%) Subtotal Contractors General Conditions @ 8% Construction Costs Contingencies and Technical Services (a~ 35% Total Capital Costs Present Worth $150,000 $150,000 15 $73,500 $100,000 $35,600 $145,800 $145,800 15 $71,400 $97,200 $37,500 $7,920,000 20 $0 $0 $0 $202,500- $202,500 15 $99,200 $135,000 $52,100 $19,821,300 $211,650 25 $0 $42,330 $16,300 $3,964,000 25 $0 $792,800 $306,000 $1,387,000 $3,964,000 20 _ _ $0 $0 $0 $29,347,950 $2,348,000 $31,695,950 $11,094,000 $42,789,950 $938,900 $4,279,330 $1,651,800 $42,790,000 $939,000 $1,652,000 Totai $332,800 $249,000 $30,000 for recycle BOD load $103,192 - $20/ton for biosolids+ 5,000/mo lease fee $286,479 $1.00/therm $97,094 $1,099,000 $13,842,000 Estimated Annual 08M Costs (30,0001bs/day; dry basis) Relative Labor ($40/hr) Maintenance (-2% of Equipment Chemicals, Additional 02 Solids Disposal Fuel Power ($0.08/kWH) Electrical Credit ($0.04/kWH) Total Present Worth of O&M Summary of Present Worth Costs Capital -Cost $42,790,000 Repiacement $939,000 O&M Cost $13,842,000 - Salvage Value ($1,652,000) TOTAL PRESENT WORTH $55,919,000 Dubuque WPCP Facilities Plan -Appendix F Alternative RM7 Drying and Agricultural Land Application Discount Rate 4.875% 20 year TPW Initial Future ITEM Capital Capital Service Replacement 20 yr Salvage Salvage Cost Cost Life Cost (P.WJ Value Value (P.WJ Sludge Processing Building Demolition and Modifications $500,000 20 $0 $0 $0 Biosolids Storage (5,000 sq. ft.) $250,000 20 $0 $0 $0 WAS Aeration Blowers (3) $202,500 20 $0 $0 $0 WAS Aeration Diffusers $50,000 $25,000 10 $15,500 $0 $0 Sludge Blending Tank (20,000 gal) $35,000 20 $0 $0 $0 Sludge Blending Tank Mixer and Controls $10,000 $10,000 15 $4,900 $6,667 $2,600 Sludge Flow Meters (3) $20,000 $20,000 15 $9,800 $43,333 $5,100 Centrifuges Feed Pumps (3) $101,250 $101,250 15 $49,600 $67,500 $26,100 Centrifuges (2) $783,000 $391,500 15 $191,700 $522,000 $201,500 Centrifuge Rehab (1) and Backdrive $80,000 $80,000 15 $39,200 $53,333 $20,600 Cake Screw Conveyors $150,000 $150,000 15 $73,500 $100,000 $38,600 High-Solids Pump Rehab $145,800 $145,800 15 $71,400 $97,200 $37,500 Drying Equipment (2 Units) $9,600,000 20 $0 $0 $0 Odor and Dust Control $337,50Q $337,500 15 $165,300 $225,000 $86,800 Subtotal $12,265,050 Sitework (5%of Building Addition) $12,500 25 $0 $2,500 $1,000 Mechanical (20%) $2,453,000 25 $0 $490,600 $189,400 HVAC (7%) $859,000 Electrical and Controls (20%) $2,453,000 20 $0 $0 $0 Subtotal $18,042,550 Contractors General Conditions @ 8% $1,443,000 Construction Costs $19,485,550 Contingencies and Technical Services @ 35% $6,820,000 Total Capital-Costs $26,305,550 $620,900 $1,578,133 $609,200 Present Worth $26,306,000 $621,000 $609,000 Estimated Annual O&M Costs (30,000 Ibs/day; dry basis) Total Relative Labor ($40/hr) $332,800 Maintenance ('y2% of Equipment) $230,000 ; Chemicals $0 Solids Disposal $165,111 _ $20/ton for biosolids+ 7,000/mo lease fee Fuel $572,959 $1.00/therm (natural gas). Power ($0.08/kWH) $97,094 Total $1,398,000 Present Worth of O&M $17,608,000 Summary of Present Worth Costs Capital Cost $26,306,000 Replacement $621,000 O&M Cost $17,608,000 Salvage Value ($609,000) TOTAL PRESENT WORTH $43,926,000