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.