NC0043176_Proportional Sampling_20010709

North Carolina
Department of Environment and Natural Resources
Division of Water Quality
Fayetteville Regional Office.
.Michael F. Easley, Governor
William G. Ross, .Jr.; Secretary
Kerr T. Stevens, Director
Mr. Joseph T. Campbell
Public Utilities Director
City of Dunn
PO Box 1065
Dunn, NC 28335
Response:
July 9, 2001
Proportional Sampling for Black River WWTP
NPDES # NC0043176
Harnett County
NCDENR
- Dear Mr. Campbell,
I am in receipt of your letter concerning effluent flow proportional sampling at the Black River
Wastewater Treatment Plant. An extension date of July 1, 2002 to complete this project is
acceptable. Please respond to our office in writing when a solution has.been implemented with
thedate of completion. Also include in the response the type of composite sampling thatwill be
implemented. Please refer to the compliance evaluation inspection dated May 29, 2001 which
. notes the four (4) types of composite sampling as stated in the Administrative Code: 15A NCAC
2B .0503-Surface Water Monitoring.
If you or your staff have any questions do not hesitate to contact me at 910-486-1541.
Sincerely,
Belinda S. Henson
Environmental Chemist
/bsh
225 GREEN STREET - SUITE 714 / SYSTEL BUILDING / FAYETTEVILLE, NC 28301-5043
PHONE [phone] FAX [phone] WWW.ENR.STATE.NC.US/ENR` •
AN EQUAL OPPORTUNITY / AFFIRMATIVE ACTION EMPLOYER- 50% RECYCLED/10% POST CONSUMER. PAPER
DENR TOLL FREE HOTLINE: [phone]

"WATER" THE GIFT OF LIFE
LACK RIVER WASTE WATER TREATMENT PLANT
POST OFFICE BOX 1065
DUNN, NORTH CAROLINA 28335
June 29, 2001
NC Division of Water Quality
Compliance Group
Ms. Blendia S. Hinson
225 Green Street, Suite 714
Fayettville, North Carolina 28301— 5043
Reference: Proportional Sampling
Dear Ms. Hinson:
am enclosing a copy of a letter that was received from our engineering firm in
reference to proportional sampling at the Black River Wastewater Treatment Plant.
This plant was originally constructed as a 2.5 MGD plant in 1979. Due to up grades
the plant is now rated at 3.7 MGD and the configuration of the effluent weir makes a
change over to proportional sampling somewhat more complicated. I feel sure that a
solution will be forth coming as soon as possible. I am requesting that an extension
of sixty to ninety days be given so that the proper method of sampling can be
engineered which will be installed by July 2002.
If you have any questions please call. Thank you.
Sincerely,
Joseph T. Campbell
Public "Utilities Director
PHONE: [phone]
FAX: [phone]
DUNNPWD@I NTRSTAR.NET

CITY OF DUNN FILTER PLANT
POST OFFICE Box t 065
DUNN, NORTH CAROLIPIA 28335
"WATER" THE GIFT OF LIFE
June 4, 2001
DAVIS — MARTIN — POWELL & ASSOCIATES
Mr. Ed Powell
218 Gatewood Avenue — Suite 102
High Point, North Carolina 27262
Reference: Flow Proportional Modifications
Dear Ed:
Enclosed is a copy of the last Compliance Evaluation Inspection at the wastewater
treatment plant. The State is requiring a response from the City by June 30,
2001 as to what measures will be taken to change to flow proportional
sampling. Since your visit to the plant have you come up with any modifications?
Please keep me advised as to what will be required and some estimate as to cost.
This item has not been budgeted for 2001 — 2002 and there is not any flexibility in
the proposed budget. If you have any questions, please call. Thanks
Sincerely,
Joseph T. Campbell
Public Utilities Director
PHONE: [phone]
FAX: [phone]
[e-mail]

DAVIS - MARTIN - POWELL & ASSOCIATES, INC.
ENGINEERING • LAND PLANNING • SURVEYING
218 GATEWOOD AVENUE • SUITE 102
HIGH POINT, NC 27262
PHONE [phone] • FAX [phone]
June 27, 2001
Re: City of Dunn
Blackriver WWTP
Effluent Flow Metering
DMP Project E-3104 (BF)
Mr. Joe Campbell
City of Dunn
PO Box 1065
Dunn, NC 28335
Dear Joe:
We are writing in response to the State's requirement for the effluent composite sampling at the
WWTP to be flow proportional as requested in their May 29th compliance evaluation inspection letter.
The letter further provides a deadline of July 1, 2002 to modify the sampling and flow measuring
capabilities to provide flow proportioned effluent sampling. The State also request a letter discussing
the plan of action by June 30, 2001.
Since the chlorine contact basin has two short effluent weir ports, an ultrasonic level sensing device
could be installed above the chlorine contact basin to measure flow rates and to send a flow
proportioned signal to an effluent sampler. We understand, however, that at high flow rates there is
little fall between the contact basins weir and the weir trough thereby creating turbulence through the
weir ports that may adversely effect the accuracy of the flow measuring device. The weir can be
adjusted to reduce this turbulence if adequate freeboard exist in the ports. If the existing effluent flow
meter does not accept a flow proportioned input the sampler may have to be modified or replaced.
These issues must be analyzed in depth to determine the most economically feasible solution to
providing a flow proportioned effluent sample.
Joe, we recommend you write the State and indicate your consulting engineer is evaluating options
available to measure flow rates at the chlorine contact basin that would allow a flow proportioned
sample to be collected. The option presented above is just the first solution we are considering.
If you have any questions, or comments, please let us know.
Very truly yours,
RM/dd.
C: Mr. Ronnie Autry
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