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WPCP State Eval ReportTHOMAS J. VILSACK, GOVERNOR SALLY J. PEDERSON, LT. GOVERNOR STATE OF IOWA DEPARTMENT OF NATURAL RESOURCES JEFFREY R. VONK, DIRECTOR September 10, 2001 City of Dubuque City Hall 50 W. 13t~ Street Dubuque, IA 52001 ATTENTION: Mayor and Council RE: Wastewater Compliance Evaluation Inspection Facility No. 31-26-0-01 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. Please note that a Plan of Action/Progress Update regarding the ongoing flood proofing improvements to the Catfish Creek Interceptor line is past due and must be submitted to this office immediately upon receipt of this report. Also, it is requested that the City Engineering Department submit a written update of their ongoing efforts to improve the sanitary sewer collection system in the Kennedy Mall area to prevent raw sewage bypassing during rainfall events. Should you have any questions, do not hesitate to write or call this office. © Sincerely, Doug A. Hawker Environmental Specialist ENVIRONMENTAL PRO~EcOTION DIVISION cf,._;- ~ O "~'~ ~::~ iT] ~_© ~ ~ Doug A. Hawker ~ ~ ~ ~ Environmen~l Specialist ~ ~ Encs. cc: Wastewater Supt. - Paul Horsfall DNR - Wastewater Section - Des Moines Water Compliance Branch - U.S. EPA, Region 7, 901 North 5th Street, Kansas City, KS 66101 Field Office 1, 909 West Main Suite 4, Manchester, iA 52057 563/927-2640 FAX 563/927-2075 l: Field office 1 Manchester I NPDES Permit #31-26-0-01 Page 1 of 3 FACiLi~ NAME: OWNER: Dubuque Munialpal Wastewater Treatment Plant City of Dubuque ADDRESS: CITY: STATE: ZIP: [ PHONE: i City Hall, 50 W. 13th Street Dubuque Iowa 52001I 563-589-4176 ~EI~¢ STPd~AM NAME: Mississippi Privet INsPECTiO~ DATE THIS INSPECTION: DATE LAST INSPECTION: 8-23-01 6-12-00 Compliance Evaluation Inspection TREA~NT [~Trickling filter [~Activated sludge ]--]RBC [--]SBR ]~Aerated Lagoon PROCESS [--]Lagoon [~Disinfection [~Other: w/dechlorination DESIG~ C~CI~ MGD: POUNDS BOD/DAY: PE (BOD): i7.3 (AWW) 24,400 i46,108 :NOw: MGD (average daily): POUNDS BOD: PE (BOD): 7.79 (July 01) 12,842 (July 01) 76,898 (July 01) RESPONsiVE NAME: GRADE: CERTIFICATION NUMBER: OPER~TOR Paul Horsfall IV 7025 :~ERSONS : NAME: TITLE: INTERVHgWED Paul HorsfaI1 Superintendent EEEL~NT SELF-MONITORING RESULTS: SAMPLES THIS INSPECTION LIMITATIONS [~Sat. [-1Marg. [-]Unsat. ]--]Sat. [~Marg. [-]Unsat. [~None collected SAMbaS TYPE: LAB DATA ATTACHED? COL~C~ N/A [] Yes SELE-MO~O~G OPERATION REPORTS REQUIRED DATA ON REPORT: TESTING ADEQUACY: SUBMITTED: [~Sat. ~]Marg. I--]Unsat. [~:~]Sat. [--]Marg. I-lUnsat. [~Sat. I-']Marg. [-]Unsat. AUT~E~C!~OI'q INSPECTOR: ~7 DATE: REVIEWER: DATE: // ~}T~ DOUG A. HAWKER DOUG A. HAWKER ENVIRONMENTAL SPECIALIST ENVIRONMENTAL SPECIALIST File Name g:dubuque01cei.doc Form VfWins.dot File # 63126001 Facility Name: Dubuque Municipal WWTP Inspection Date: 8-23-01 Page 2 of 3 Observations & Recommendations: On August 23, 2001 I inspected the wastewater treatment plant that serves the City of Dubuque. I met with Wastewater Superintendent, Paul HorsfalI, and toured the facilities. Below is a list of observations made and comments received during the course of this inspection. DESCRIPTION: There is one permitted discharge that has monitoring and reporting requ/rements 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. This facility utilizes a high purity oxygen activated sludge process. The treatment units consist of two mechanically cleaned bar screens, two combination grease, gdt and flocculation units, three primary clariflers, three separate oxygen activated sludge basins, four final clarifiers, effluent disinfection using gas chlorine, and dechlorination. Sludge removed from the primary and final clariflers is thickened by centrifugation and standby belt presses, prior to being burned in a fiuidized 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 at Special Waste Authorization (SWA). OBSERVATIONS: On the date of this inspection, one of the two gdt removal chambers was on line. These units did not plug up with mud and debris this year during high flow conditions as has happened in the past. This is due to Dubuque's ongoing efforts to improve the tightness of their various sanitary sewer lines throughout town over the past couple of years, especially on the northwest end of the Catfish Creek interceptor. This has cut back on the amount of c~trt and mud that comes down this line to the WWTP. All clarifiers were on line and working well on this date. Two of three aeration basins were on line with the third being on standby. No problcn~as were reported with any of the aeration basins. The chlorine contact chamber was on line and working well. The final effluent appeared to be very clear on this date. In the solids handling portion of the WWTP, one of two sludge incinerators has been taken off line for annual maintenance. One of the two centrifuges is also offline for some mimtenance work. Both the ash lagoons are getting full and they will need to be cleaned out in the immediate future. 6. Housekeeping around the plant appeared to be good. The grounds are being maintained well. A review of the past year's monitoring reports shows that Dubuque has routinely been producing a good quality effluent. However there were some discharge violations in February and April of this year. In February a major Spring thaw occurred along with some significant cold rainfall events. Temperatures of the wastewater dropped 15° F at th/s time which essentially shut down the bacteria with'm the treatment plant. This resulted in a violation of the maximum 7 day average 10. CBOD5 concentration limit as well as the 30 day average TSS concentration limit, the maximum 7 day average TSS concentration limit, and the maximum 7 day average TSS mass limit. The effluent recovered quite well in March. However, in April, very high flows associated with extensive flooding throughout the Mississippi River basin once again caused some TSS discharge violations. Specifically, there were violations of the 30 day average TSS concentration limit (by only 1 mg/1), the maximum 7 day average TSS concentration limit, and the maximum 7 day average TSS mass limit. These violations were attributed to leaking and damaged manholes along the Catfish Creek interceptor line. Dubuque continues to work to decrease the infiltration and inflow of extraneous water into the sanitary sewer collection system during precipitation events. During a July 11, 2001 visit to the Dubuque WWTP by Jerry Rattenborg of this office, the City of Dubuque was given an August 1a deadline to submit a Plan of Action (POA) to the DNR outlining the steps that will be taken to address these apparent recurring problems along the Catfish Creek interceptor. To date, this POA has not been submitted and is overdue. As part of my inspection, Paul Horsfall and I did look at several areas along the Catfish interceptor and noted that City crews have gotten some of the questionable manholes repaired and/or improved. At this time, it is requested that the City submit the POA and an update as to what work has already been done to date to address these problems. This should be done immediately upon receipt of this report. In addition to the above required POA, it is also requested that the Dubuque Engineering Department send FO #1 a written update on their efforts to improve the sanitary sewer collection system in the Kennedy Mall area. Despite the relatively recent, multi-phase, improvement projects at the WWTP, this facility continues to show it's age. The City must realize that this facility will continue to need an ever increasing amount of maintenance activities in order to continue to operate in consistent compliance with all present and future discharge limitations. The City will eventually need to consider adding additional maintenance personnel at this facility in order to accomplish these objectives. 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 final discharge was very clear and no significant problems were noted. As noted during last year's inspection report, the City of Dubuque must continue to concentrate their infrastructure maintenance efforts on their sanitary sewer collection problems. The two areas of greatest concern at this time are the Catfish Creek interceptor line and the sanitary sewer collection system in the Kennedy Mall area. Efforts must continue to "flood proof-' the Catfish Creek interceptor. The past due POA (and progress update report) regarding these efforts should be submitted to this office immediately. The sanitary sewer collection system in the northwest part of town near Kennedy Mall must also be improved to prevent all bypasses of raw sewage during heavy precipitation events. Also, it is this department's feeling that at least some of the town of Asbury's sanitary wastes will someday be pumped to the Dubuque WWTP for proper treatment. The sanitary sewer lines between Asbury and the Dubuque WWTP must be able to handle this in the not too distant future. Except for the previously noted TSS violations, the Dubuque WWTP has rout'mely been in compliance with all NPDES permit limitations throughout the past year. For the most part, the Dubuque WWTP does a very f'me job of treating the town's wastewater to acceptable discharge levels. The rune and cooperation of Mr. Horsfall during the course of this inspection was appreciated.