IDNR Dubuque Wastewater Treatment Facility Inspection®®`t(1®d~ - ~
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Fields of Opportunities
CHESTER J. CULVER, GOVERNOR "`` r'rb rs sw ' ~ ~ sF ~~
DEPARTMENT OF NATURAL RESOURCES
PATTY JUDGE, LT. GOVERNOR
,..,,,, , ,..., i -. -~. RICHARD A. LEOPOLD, DIRECTOR
March 31, 2009
City of Dubuque
50 West 13'h St.
Dubuque, IA 52001
ATTN: Honorable Mayor & City Council
RE: Dubuque Wastewater Treatment Facility Inspection
NPDES Permit #: 3126001
Dear Honorable Mayor & City Council:
Enclosed is the report of the recent inspection of the above~facility conducted by Sue Miller of the Field
Office #1 staff.
We believe you will find the report self-explanatory and strongly encourage you to take action on the
requirements and/or recommendations listed at the end of the report.
If you have any questions about the inspection or report, please contact Sue Miller or myself at this office.
Sincerely,
V
Mike Wade
Environmental Specialist
cc: DNR Records Center (w/encl.)
Michael Van Milligan, City Manager, City Hal(, 50 W. 13th St., Dubuque, IA 52001 (w/encl.)
Jonathon Brown, WPCF, 795 Julien Dubuque Dr., Dubuque, IA 52003
File: WW/Dubuque
eFi[e; 31 WW Dub~~q~~e 032609 ins sjm
FIELD OFFICE #1 / 909 West Main Suite 4 / Manchester, IA 502057
563-927-2640 / FAX 563-927-2075
I IO1NA Dl=PARTMENT OF NATURAL RESOURCES
__
- WASTEWATER TREATMENT FACILITY iNSPECTIC7N
NPDES.Permit #::.3126001- Page 1 of 4-
FACILITY INFORMATION _... .
FACILITY NAME: PLANT GRADE:
City of Dubuque Water Pollution Control 1V
RESPONSIBLE AUTHORITY/OWNER:
Cit of Dubuque
ADDRESS: CITY: STATE: ZIP: PHONE:
50 West 13th St. Dubuque Iowa 52001 563/589-4110
RESPONSIBLE NAME: GRADE: CERTIFICATION NUMBER:
OPERATOR Jonathon Brown 1V 1671
DESIGN AVERAGE MGD: MAXIMUM MGD: POUNDS BOD/DAY: PE (BOD):
CAPACITY 17.32 23.24 24400 146108
NOW AVERAGE MGD: MAXIMUM MGD POUNDS CBOD/DAY: PE (BOD):
TREATING 9.0 (2007 & 2008) 26.816 (June 2008) 6624 (July 2008) 39,665 (July 2008)
PERIOD REVIEWED: POPULATION SERVED:
5/01 /2002 - 7/1 /2006 52,895
RECEIVING Mississippi River- A1, B(WW1)
STREAM
GENERAL
DESCRIPTION: Pure 02 Activated sludge treatment plant
INSPECTION tNF:ORMATIO_N
.. ---
INSPECTION DATE THIS IN_ SPECTION: DATE LAST INSPECTION: PURPOSE:
3/26/2009 07/25/2006 Routine Compliance Inspection
PERSONS NAME; TITLE;
INTERVIEWED Jonathon Brown Wastewater Plant Manager
John Klostermann Public Works Director
NPDES'PERMIT COMPLIANCE SUMMARY
SELF- Operation Reports Submitted: Required Data on Reports: Testing Adequacy:
MONITORING ®Sat. ^ Marg.* ^ Unsat.* ®Sat. ^ Marg.* ^ Unsat.* ®Sat. ^ Marg.* ^ Unsat.*
EFFLUENT SELF-MONITOR[NG RESULTS:
LIMITATIONS ®Satisfactory ^Marginal* ^ Unsatisfactory*
SAMPLES THIS TYPE: LAB DATA ATTACHED?
1NSPECTION None. ^Yes ^ No
RESULTS:
^ Satisfactory ^Marginal* ^ Unsatisfactory*
VISUAL APPEARANCE OF EFFLUENT: VISUAL APPEARANCE OF RECIEIVING STREAM:
clear ~ Not observed
COMPLIANCE COMPLIANCE WITH SCHEDULE: NEXT ITEM DUE: DATE DUE:
SCHEDULE ^ Sat. ^ Marg.* ^ Unsat.*
Explain in comments and Hecommendatlons section
Au T HEidICATivly
INSPECTOR: NAM :Sue Miller, Environmental Specialist DATE:
~-~) ~y
REVIEWER: -NAME: Mike Wad, Environmental Specialist: DATE:
f ~ ~.
.City of Dubuque WastewaterTreatment Inspection Irispecfiori Date_07/25/0.6.:
.:'NPDES Permit #: 3126001 - Page 2 of 5 .
NPDES PERMIT COMPLIANCE:
The monthly operation reports (MORs} were reviewed for the reporting period from January 2007 through
February 2009.
Design Capacity/Effluent Limitations -During the above mentioned reporting period the following
observations were made:
® The design influent flow rates are 17.32 MGD AWW and 23.24 MGD MWW. During the above mentioned
reporting period the facility was in compliance with the facility design flow, except for April and June 2008
when the MWW was exceeded.
® The 30-day and 7-day average CBODS effluent limitations are 25 mg/L and 40 mg/L respectively. The 30-
day (imitation was exceeded in July 2007 and July 2008, while the 7-day limitation was exceeded during
July 2008.
® The 30-day and 7-day average total suspended solids (TSS) effluent limitations are 30 mg/L and 45 mg/L
respectively. The 30-day limitation was exceeded during June and July 2007; and July 2008, while the 7-
day limitation was exceeded during July 2007 and June and July 2008.
® The daily maximum fecal coliform effluent limitation is 200 organisms/100 ml. The facility was in
compliance with the fecal coliform limitations of the NPDES permit during the reporting period.
® The 30-day and daily maximum total residual chlorine (TRC) effluent limitations are 0.151 mg/L and 0.202
mg/L respectively. The 30-day average was exceeded during May 2008, while the daily maximum effluent
limitation was exceeding in May and June 2008.
FACILITY EVALUATION:
PRE-TREATMENT UNITS (This Facility)
Raw influent is delivered to the City of Dubuque WWTF via two separate forcemairis and enters the facility
through bar screens followed by two grit basins. The grit slurry is then normally transported to two grit
removal units, both grit removal units were in operation on the day of ibis inspection.
TREATMENT UNITS
Primary treatment is provided by three, covered primary clarifiers. At the time of this inspection all three
primary clarifiers were operating.
Secondary treatment is provided in three, pure oxygen. activated sludge basins. Only two basins were
being operated and the third basin was operating as a standby basin. The basins are covered and nine (9)
mechanical mixers located on top of each basin. Oxygen is controlled by sensors located in the
headspace.
Four final clarifiers provide final settling. All four clarifiers were operating on the day of this inspection.
Disinfection is provided by the addition of liquid chlorine prior to a chlorine contact chamber. The effluent is
dechlorinated with sodium bisulfite prior to discharge.
SLUDGE HAN®LING AN® ®ISPOSAL
This facility does not have a sludge digester. Primary sludge and secondary sludge are stored separately
and blended at a 55/45 primary to secondary ratio before dewatering via centrifuge. The sludge is
dewatered to 28% solids before feeding to the fluidized bed incinerator. Final disposal is in the on-site ash
ponds. The north incinerator has recently been reinforced with additional bracing and steel plating.
~;ify o#Dubu.que;VVastevvater Treatment Inspection ~ Inspection Date: 07/25/Q6
NPDES Permit #: 3126Q01 'Page'3 of 5
FL®W MEASUREMENT
Magnetic meters on the two influent forcemains are the reported flow measurement at the plant. The
effluent flow is also measured by a pressure transducer and flume. The magmeters were calibrated this
spring according to Mr. Brown to ensure accurate flow readings are being reported.
PUMPING
One intermediary pump station is located between the old 200' diameter, trickling filters and the activated
sludge basins. These pumps serve to pump excess rainwater out of the uncovered, unused trickling
filters. The City has installed a valve to allow inflow to be diverted into the unused aeration basin during
times of high flow.
EMERGENCY POWER
Mr. Brown reported that the wastewater treatment plant is served by two separate power sources. Several
of the lift stations have no back up power source. The City maintains two portable generators that can be
used at the four lift stations that have connections for them. The Cedar lift station has been renovated and
has a standby generator. The Dog Track lift station has a connection for a portable generator. The
Terminal Street lift station is undergoing renovation and will have a standby generator. The Catfish Creek
lift station will soon have a standby generator.
LIFT STATION (S)
Operation and Maintenance- The City of Dubuque maintains the following 12 lift stations:
1. Kerper Boulevard- This lift station is located in a building in the median of Kerper Blvd. The pumps
were being replaced in this lift station the day of this inspection. The two pumps are 15 hp turbines.
The lift station has no high level alarm and is not connected to the SCADA system at the treatment
plant. There is an overflow at this lift station identified on the NPDES permit as Outfall 005.
2. Dog Track- This lift station was recently renovated to install two, new 640 gpm, 15-hp submersible
pumps. There is an overflow at this lift station that is not listed as an outfall on the facility NPDES
permit. The City must ensure that the new permit application includes this overflow.
3. Cedar Street- This lift station was recently renovated to install three, new 6,000 gpm, 200 hp, VFD
pumps. The lift station also has a new standby generator. There is an overflow at this lift station
identified on the NPDES permit as ~utfall 002. The overflow was not eliminated in the renovation,
but a new control valve was installed to keep storm water from entering from the B-Branch storm
sewer.
4. Terminal Street- This lift station contains 3-350 hp turbine, flow-variable pumps. The speed of the
pumps is regulated by a liquid rheostat. The lift station has no high level alarm and is not
connected to the SCADA system at the treatment plant. There is an overflow at this lift station
identified on the NPDES permit as Outfall 003.
5. Granger Creek- This lift station serves the area south of the City including the Technology Park.
Wastewater from the Granger Creek lift station-
o. CatflS h Creek- This lift station pumps VVCtsLEVVatEI that IS COIIectEd from the Entire west end of file
City from Grandview Avenue to the new industrial park on Seippel Road. Field Office records show
that this lift station was rebuilt in 2000. The lift station is equipped with three, 2,500 gpm
submersible pumps. There is an overflow at this lift station identified on the NPDES permit as
Outfall 004.
7. Bradley Street- This lift station is located in a residential yard. It has no alarm, but is checked
weekly by City personnel. There is an overflow at this lift station identified on the NPDES permit as
Outfall 006.
8. Perry Street- This lift station is located in a residential yard. It has no alarm, but is checked weekly
by City personnel. There is an overflow at this lift station identified on the NPDES permit as Outfall
007.
-City of:Dubuque Wastewater Treatment Inspection Inspection Date: 07/25/06
_..
NPDES Permit #: 3126001 ;Page 4:of ~
9. Asbury Plaza- This lift station, which is equipped with two, 215 gpm submersible pumps, was
constructed in 2002. The lift station has an audio-visual alarm.
LIFT srATloN~s~ ~cont°d.)
10. Asbury Plaza 2 -This lift station is still under construction, but is almost complete. When complete,
the lift station will be equipped with two, 400 gpm submersible pumps with VFD, a cellular dialer
alarm and a diesel powered standby generator.
11. Arboretum Drive- This lift station, which is equipped with two, 325 gpm submersible pumps, was
constructed in 2001. The lift station has an audio-visual alarm.
12. Cedar Cross Road- This lift station is located in a commercial area. The lift station has an audio-
visual alarm.
PREVIOUSLY NOTED DEFICIENGES:
The previous inspection in July 2006 noted that the City of Dubuque wastewater plant had difficulty
maintaining compliance with total suspended solids effluent limitations during times of high flows. Part of the
problem at the time was that some treatment units were out of service and the sludge inventory in the plant
was high. On the day of the current inspection, all treatment units were in operation. The sludge blanket in
the final clarifiers did not appear to be excessive and the effluent was clear.
The treatment plant still experiences excursions for TSS during times of high flow, however. The City has
submitted and the department has approved a Facility Plan for extensive improvements at the Dubuque Water
Pollution Control Facility. The proposed improvements include additional primary clarification, flow
equalization using the two old trickling filters, replacing the mixing equipment in the aeration basins,
converting from chlorine disinfection to uV disinfection and adding anaerobic sludge digestion to eliminate the
incinerators. Now that the department has approved the Facility Plan, the City must submit Plans and
Specifications to the department.
Bypasses
The City continues to experience flows that overwhelm the sewer system on the west side of town along the
North Fork Catfish Creek interceptor sewer. A review of the file shows that since the last inspection the Key
Way Drive location along this interceptor has been pumped to prevent basement backups at least 18 times.
The City has submitted plans and specifications for capacity improvement of the North Fork Catfish Creek
interceptor. The Gity expects construction to be initiated this year.
A sewer blockage occurred further west on this line in March 2009. The cause was determined to be grease.
originating somewhere in the Asbury Plaza shopping center. The Gity Health Department is going door-to-
doorinspecting all of the restaurants and food preparers that are served by this line to determine compliance
with the city's ordinances.
The City has identified several other problem areas in the collection system. They have established a post
cleaning CCTV program. Anew CCTV unit was purchased in 2007. The City also has a portable unit. All of
the collection system is now on ulS and the public works staff are updating with handheld units.
SUMM~,RY OF RE®UIRMENTS
Now that the department has approved the Facility Plan, the City must submit Plans and Specifications to the
department.
SUMMARY OF RECOMMENDATIONS