NC0043176_Annual Performance Report_20050209

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CITY OF DUNN
POST OFFICE BOX .1065 • DUNN \NORTH CAROLINA 28335
PUBLIC WORKS DEPARTMENT • [phone] • FAX [phone]
CITY OF DUNN WASTE WATER TREATMENT PLANT
ANNUAL PERFORMANCE REPORT
I. GENERAL INFORMATION:
Facility Name: Black River Wastewater Treatment Plant
Contact Person: Billy Addison
Responsible Entity: City of Dunn
Applicable Permit #: NC0043176
Telephone Number: 910-892-2948
DESCRIPTION OF TREATMENT PROCESS:
The City of Dunn/Black River Waste Water Treatment Plant uses the extended aeration
mechanical and biological processes to treat the waste water entering the plant. The raw
waste water enters the plant through a 30" gravity sewer main which goes through three
enclosed 1580 GPM each lift pumps and one standby T-12 4000 GPM Gorman Rupp
standby pump to handle higher flows in emergency situations. The flow then passes thru
a mechanical barscreen which removes floating material and then passes thru an aerated
grit chamber which allows flow to flow less than 1 foot per second which allows any
heavy materials (sand and organics, etc.) to be removed. The flow then goes ' thru a
partial flow measuring devise, where flows are measured and samples are taken 24 hours
per day for operation and analytical control. The flow goes then to a diversion box that
splits the flow between aeration basins where diffused air is forced under pressure by
three turbin blowers for the bacteria to live function, reproduce in the biological process.
The flow leaves the aeration basins thru a trough at the end of each basin and goes to
another diversion box where the flow is split again and is divided and sent to three 60 ft.
diameter clarifiers. The flow leaves clarifiers and goes over the. V-notch weirs and flows
to a CL2 contact chamber where disinfection and declorination takes place before the
flow enters into the wet well of a final pumping station where 3 5000 GPM pumps 'which
are on variable speed drive controls and pump the final treated effluent 3 % miles to the
Cape Fear River where it is discharged. In the clarification process, sludge is settled in
the clarifiers and siphoned to a return sludge pumping station where the sludge is
recycled to the head of the aeration basins. A portion of the sludge is pulled thru a DAF
(Diffused Air Flotation Unit) where fme air bubbles and polyemers are added to thicken
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the sludge before it is pumped to an aerobic digester where air is added for final
stabilization of the sludge. The sludge is then pumped to a 600,000 holding tank where
the sludge is held until volumes and hold times are met so as to meet all vector
requirements. The sludge is then hauled .out to by tanker trucks and applies to an EPA
permitted farm site and applied for fertilization at agronomic rates.
II. PERFORMANCE:
The City of Dunn Waste Water Treatment Plant received only one (1) permit violation
for 2004 which was a flow violation for September 2004 and was below the 10%
acceptance limit, and was due to extremely high rain fall total for September 2004.
M. This report was published in The Dunn Daily Record local newspaper and run on the City
Local Government cable tv channel. If you have questions concerning this report, please
contact Billy Addison at the City of Dunn Public Works Department [phone] or
Bobby Burnette at the Black River Waste Water Treatment Plant at [phone].
IV. CERTIFICATION:
I certify under penalty of law that this report is complete and accurate to the best of my
knowledge. I further certify that this report has been made available to the or
customers of the named system and that the users have been notified of its availability.
Billy Ad son
Assis Public Works Director
City of Dunn - NC