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Wastewater Compliance Evaluation Inspection reportTHOMAS J. VILSACK, GOVERNOR SALLY J. PEDERSON, LT. GOVERNOR July 19, 1999 City of Dubuque City Hall 50 West 13 Street Dubuque, IA 52001 Encs. WA ATTENTION: Mayor and Council Ron Stellick Environmental Specialist Field Office #1 909 West Main St. - Suite #4 Manchester, Iowa 52057 Phone: 319/927 -2640 Fax: 319/927 -2075 RE: Wastewater Compliance Evaluation Inspection Facility No. 31- 26-0-01 DEPARTMENT OF NATURAL RESOURCES PAUL W. JOHNSON, DIRECTOR u 7-3 We have enclosed the inspection report prepared by our Field Office Staff and a copy for your wastewater operator. You will find the inspection report self - explanatory. We encourage you to make every effort to comply with the recommendations. Should you have any questions, do not hesitate to write or call this office. Sincerely, ENVIRONMENTAL PROTECTION DIVISION 11 0 cc: Wastewater Supt. — Paul Horsfall DNR - Wastewater Section - Des Moines Water Compliance Branch - U.S. EPA, 726 Minnesota Avenue, Kansas City, KS 64i 01 WALLACE STATE OFFICE BUILDING / DES MOINES, IOWA 50319 / 515- 281 -5145 /TDD 515 - 242 -5967 / FAX 515 - 281 -8895 NPDES Permit #31- 26-0-01 FACILITY RECEIVING STREAM INSPECTION TREATMENT PROCESS DESIGN CAPACITY NOW TREATING RESPONSIBLE OPERATOR PERSONS INTERVIEWED EFFLUENT LDIIITATIONS SAMPLES COLLECTED SELF - MONITORING AUTHENTICATION NAME A 'I TLL File Name g:dubuque.cei Form WWins.dot File # 63126001 IOWA DEPARTMENT OF NATURAL RESOURCES WASTEWATER TREATMENT FACILITY INSPECTION NAME: OWNER: Dubuque Municipal Wastewater Treatment Plant City of Dubuque I ADDRESS: CITY: STATE: ZIP: City Hall, 50 W. 13th Street I Dubuque Iowa 1 52001 I STREAM NAME: Mississippi River I DATE THIS INSPECTION: I DATE LAST INSPECTION: 7 -1 -99 I 8 -26 -98 I PURPOSE: Compliance Evaluation Inspection ❑Trickling filter Lagoon QLagoon MGD: 17.3 MGD (average daily): 14.1 (May 99) NAME: Paul Horsfall NAME: Jon Brown TYPE: N/A OPERATION REPORTS SUBMITTED: ®Sat. ❑Mary;. UUnsat. INSPECTOR: ENVIRONMENTAL SPECIALIST Field Office 1 Manchester Activated sludge ❑RBC ®Dis'nfection ®Other: w/ dechiorination POUNDS BOD/DAY: 24,400 POUNDS BOD: 17,428 (May 99) GRADE: IV 17025 TITLE: Assistant Plant Manager REQUIRED DATA ON REPORT: QSat. DMarg. SIGNATURE DATE: . -i_ 97 REVIEWER: DOUG A. HAWKER RON STELLICK PE (BOD): 146,108 PE (BOD): 104,359 (May 99) ENVIRONMENTAL SPECIALIST Page 1 of 3 I PHONE: ❑SBR ['Aerated CERTIFICATION NUMBER: PERMIT COMPLIANCE SUMMARY SELF - MONITORING RESULTS: SAMPLES THIS INSPECTION _NSat. ❑Mara. DUnsat. ❑Sat. ❑Mang. ❑Unsat. None collected LAB DATA ATTACHED? Q Yes EiNo TESTING ADEQUACY: ®Sat. ❑Mar ■ U DUnsat. neat. DATE: 7 - 1/ -q77 . Facility Name: Dubuque Municipal WWTP Inspection Date: 7 -1 -99 Page 2 of 3 OhservationsJJ Recommendations: On July 1, 1999, I inspected the wastewater treatment plant that serves the City of Dubuque. I met with Assistant Plant Manager, Jon Brown, and toured the facilities. Mr. Paul Horsfall was on vacation on this date. Below is a list of observations made and comments received during the course of this inspection. DESCRIPTION: 1. There is one permitted discharge that has monitoring and reporting requirements listed on the NPDES permit for this facility. Outfall 001 is listed as the discharge from an activated sludge WWTP. The discharge enters directly into the Mississippi River. Outfalls 002, 003, 004, 005, 006, and 007 are listed as various lift station overflows located throughout the sanitary sewer collection system. 2. This facility utilizes a high purity oxygen activated sludge process. The treatment units consist of two mechanically cleaned bar screens, two combination grease, grit and flocculation units, three primary clarifiers, three separate oxygen activated sludge basins, four final clarifiers, effluent disinfection using gas chlorine, and dechiorination. Sludge removed from the primary and final clarifiers is thickened by centrifugation and standby belt presses, prior to being burned in a fluidized bed incinerator. Ash is transported to a pair of ash storage lagoons on site. It is periodically dried and hauled to the Dubuque County Landfill with a Special Waste Authorization (SWA). OBSERVATIONS: 3. On the date of this inspection, all treatment units were on line and operating well. It is noted that extremely heavy rains throughout Northeast Iowa in mid -May caused an excessive amount of mud, sand and grit to wash into the treatment plant. The heavy rains and associated storm water runoff actually dislodged manholes along the Catfish Creek basin allowing flood waters to flow directly into the sanitary sewer collection system. The excessive mud plugged both the grit removal units and impacted the sludge incineration process. This problem appears to be ongoing during times of heavy precipitation. The City is encouraged to continue their infiltration and inflow reduction program thereby decreasing the amount of sand and grit entering the sanitary sewer collection system. 4. On the date of this inspection, the final effluent from the chlorine contact chamber appeared to be very clear. This facility has routinely remained in compliance with all NPDES permit discharge limitations since the date of the last inspection on June 19, 1997, with the exception of TSS violations in April and May 1999 and with CBOD5 violations in May 1999. These violations resulted from intense precipitation events that hydraulically overloaded the plant and washed suspended solids out of the final clarifiers. 5. Earlier this past Spring, Dubuque helped the neighboring town of Asbury by taking Asbury's wastewater for several weeks while the Asbury wastewater lagoon system was taken off line for cleaning and repair. 6. As noted in last year's inspection report, there are a number of old valves, pumps, and other metal structures located in corrosive environments, primarily near the headworks area of the WWTP that are showing excessive rust damage. Most of these metal structures are quite old and were not replaced during the recently completed plant upgrade. Repairing, painting, and/or replacement of these aging units need to ' be given a high priority by the City. Nothing was done since the last inspection to address these problem areas. 7. It is noted that the general housekeeping around the treatment plant grounds has improved since the last inspection. The plant grounds are looking very good. The City is encouraged to continue with their efforts to keep the plant grounds clean and free of accumulating piles of old metal parts, scrap, etc. 8. Dubuque continues to have excessive infiltration and inflow entering into the sanitary sewer collection system during precipitation events. These excessive flows routinely result in the direct bypass of raw sewage at several points within the collection system. This office has met with the City regarding this matter. Dubuque has developed a fairly comprehensive Sanitary Sewer Action Plan and is actively pursuing infiltration and inflow reduction efforts for FY 1999 and FY 2000. 9. The Dubuque WWTP laboratory received their most recent certification to perform wastewater analysis in March 1999. CONCLUSIONS AND RECOMMENDATIONS: The Wastewater Treatment Plant that serves the City of Dubuque was in good overall condition on the date of this inspection. The plant grounds appeared to be in better overall condition then they have for the past several years. All major construction activities at this plant have been completed and the impacted areas have been groomed and seeded. The City of Dubuque must continue to concentrate their infrastructure maintenance efforts on their sanitary sewer collection problems. The city should continue to keep this office informed as to the progress being made to eliminate the routine bypasses of raw wastewater from the collection system during heavy rains. As noted in the previous inspection report. There are a number of old valves, piping, and other metal structures throughout the headworks portion of the WWTP that are becoming extremely corroded. The City needs to evaluate these metal structures and either repair, paint, or replace them as needed. The time and cooperation of Mr. Brown during this inspection is appreciated.