IDNR Report Water Poll. Ctrl PlSTATE OF IOWA
TNOmAS J. VILSACK, GOVERNOR
SALLY J. PEDER$ON, IT. GOVERNOR
DEPARTMENT Of NATURAL RESOURCES
JEFFREY R. VONK, DIRECTOR
June 17, 2002
City of Dubuque
City Hall
50 West 13th 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.
Should you have any questions, do not hesitate to write or call this office.
Sincerely,
ENVIRONMENTAL PROTECTION DIVISION
Ron Stellick
Environmental 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
IOWA DEP~TMENT OF NATURAL RESO~CES
WASTEWATER TREATMENT FACILITY INSPECTION
Field Office 1 Manchester
NPDES Permit #31-26-0-01 Page 1 of 3
FACILITY NAME: OWNER:
Dubuque Municipal Wastewat~r Treatment Plant Cit7 of Dubuque
ADDRESS: CITY: STATE: ZIP: PHONE:
i City Hall, 50 W. 13th Street Dubuque Iowa 52001 563-589~4176
RECEIVING STREAM NAME:
STRE~ Mississippi River
INSPECTION DATE THIS INSPECTION: DATE LAST INSPECTION:
5-20-02 8-23-01
PURPOSE:
Compliance Evaluation Inspection
TREATMENT [--]Trickling filter [~Acfivated sludge ['-]RBC ['-]SBR [~Aerated Lagoon
PROCESS [-]Lagoon [~Disinfection [~Other: w/dechlorination
DESIGN CAPACITY MGD: POUNDS BOD/DAY: PE (BOD):
17.3 (AWW) 24,400 146,108
NOW MGD (av~'age daily): POUNDS BOD: PE (BOD):
TREATING 8.38 (May 02) 18,966 (May 02) 113,569 (May 02)
I
RESPONSIBLE NAME: GRADE: CERTIFICATION NU2V!BER:
OPERATOR Paul Hors£all IV 7025
PERSONS NAME: TITLE:
INTERVIEYVED Paul Hors£all Superintendent
PERMIT COMPLIANCE SUM2VIARY
EFFLUENT SELF-MONITORING RESULTS: SAM?LES THIS INSPECTION
LIMITATIONS [~]Sat. [~Marg. [~Unsat. [--]Sat. [-]Marg. [-]Unsat. [~None collected
sAMpLES TYPE: LAB DATA ATTACHED?
COLLECTED N/A [] Yes [~No
SELF-MO~3[TORING OPERATION REPORTS REQUIP~D DATA ON REPORT: TESTING ADEQUACY:
SUBMITTED:
[~Sat. [-]Marg. [--]Unsat. [~Sat. ~]Marg. [~Unsat. [~Sat. [--]Marg. [~Unsat.
t SIGNATURE
NAME & TITLE DOING A. HAWI~R t I~ON STELLICK
ENVIRONMENTAL SPECIALIST ENVIRONMENTAL SPECIALIST
File Name g:dubuque02cei.doc
Form WWins.dot
File # 63126001
Facility Name: Dubuque Municipal WWTP
Inspection Date: 5-20-02
Page 2 of 3
Observations & Recommendations:
On May 20, 2002 1 inspected the wastewater treatment plant that serves the City of Dubuque. I met with
Wastewater Superintendent, Paul Horsfall, 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 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 Pdver. 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 treahuent 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 dechlorination. Sludge removed from the primary and final
clarifiers is thickened by centdfugation 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 at Special Waste Authorization
(SWA).
OBSERVATIONS:
On the date of this inspection, one of the two grit removal chambers was on line. These units
continue to operate fairly well. It appears that the significant efforts that the city has put forth over
the past several years to improve the condition of the various sanitary sewer trunk lines has
markedly decreased the amount of grit and mud washed into the treatment plant during high water
events.
All clarifiers were on line and working well on this date. It must be noted that the primary
clarifiers continue to be in a steady state of deterioration despite being refurbished several years
ago. The corrosive enviromnent within the cover domes over these clarifiers continues to promote
corrosion of the various metal structures of these units. The City will need to be replacing,
refurbishing, or improving these important treatment units at some point of time in the not too
distant future. Two of three aeration basins were on line with the third being on standby. No
problems 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, the north incinerator reactor has recently been
refurbished and was scheduled to be brought back on line over the next week or so. Once this
comes back on line, the south incinerator reactor will be taken down for a major refurbishment. In
addition, one of the two sludge centrifuges has also been taken offline for armual maintenance
purposes.
6. Housekeeping around the plant appeared to be good. The grounds are being maintained well.
WWTP personnel will be replacing the slide gates at the splitter box for the aeration basins later
this fall. Once this is done, it will be possible to refurbish the inside of the aeration basins. Two
out of the three basins will eventually be cleaned, water blasted, and coated with a plastic-type
sealant. These basins are the mare treatment units of this WWTP. It has been quite a few years
since they have been taken off line for maintenance.
A revie~v of the past year's monitoring reports shows that Dubuque has routinely been producing a
good quality effluent. However, a rev/e~v of our NPDES data base since the date of the last
inspection of this facility in August 2001 shows that the maximum 7 day Total Suspended Solids
(TSS) limits were exceeded in October 2001 as well as in January and March 2002.
The Dubuque Municipal Wastewater Laboratory continues to be certified to do wastewater
analysis.
10.
The city continues to implement a multi-year sanitary sewer infiltration/inflow reduction program.
Plant personnel have noticed a significant reduction of flows during wet weather as a result of
these efforts. Thus far this past spring, there have been about two weeks of high water in the
Dubuque area. There has been minimal infiltration along the Catfish Creek interceptor line,
however the Granger Creek line appears to have an infiltration or inflow problem that hasn't yet
been located. It is further noted that since the date of this inspection, the Dubuque area
experienced extremely heavy rains (as did areas further to the west and south). The City of
Dubuque did experience some bypassing w/thin the sanitary sewer collection system as a result of
these extremely heavy rains. It is Lmportant that the City of Dubuque continue their
infiltration/inflow reduction efforts for the foreseeable future.
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 in the text of this report, the covered primary clarifiers are showing signs of degradation due to
the/r corrosive environment. These un/ts must be watched closely and the city must be aware that these
important units will need some sort of maintenance upgrade in the foreseeable future.
The City is to be complimented on their ongoing efforts to reduce infiltration and inflow throughout the
sanitary sewer collection system.
The time and cooperation of Mr. Horsfall during the course of this inspection was appreciated.