NC0026352_Technical Assistance_20010823

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NCDENR
North Carolina Department of Environment and Natural Resources
Michael F. Easley, Governor
August 23, 2001
Lynn Brisson
ORC, Wastewater Treatment Facility
Hydro Management Services, Contract Operations
Town of Bladenboro
P.O. Box 445
Bladenboro N.C. 28320
William G. Ross Jr., Secretary
Gregory J. Thorpe, Ph,D.
Acting Director
Division of Water Quality
Subject: Technical Assistance
Bladenboro Wastewater Treatment Facility
N.P.D.E.S. NC0026352
Bladen County
Dear Mr. Brisson,
Thank -you for meeting with Belinda Henson and myself as we combined the annual plant
inspection with a technical assistance visit. The plant tour of your facility was most informative
and your cooperation was most appreciated.
The following items are to be considered to enhance the operation and compliance of your
treatment facility;
1. The manual barscreens are being replaced at facilities such as yours, that are not manned 24
hours per day, with automatic screens. The automatic screens prevent high flow surges through
the wastewater treatment plant due to infrequent cleaning. The automatic screens will also
reduce the risk of (SSO) sanitary sewer overflows in the collection system due to flowbacking
up when the screen is clogged. This should be considered for future budget considerations.
2. The return sludge pumps are operating at 100% capacity. This is putting an increased
hydraulic loading on the clarifier and reducing it's effecientcy. The clarifier would perform
more efficiently if it were returning approximately 50% of the influent flow. Since you do not
have a return sludge flowmeter, I would recommend slowing the flow by throddling the
discharge valve at the pump. This should slowly be accomplished by reducing the flow each day
until the return TSS ranges between 9-12,000 mg/1. Make sure that you do not have pump
cavitation (rattling or vibration) when you are restricting the flow.
Fayetteville Regional Office
225 Green Street — Suite 714, Fayetteville, North Carolina 28301-5043
Phone: [phone] FAX: [phone] \ Internet: www.enr.state.nc.us/ENR
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Bladenboro T.A.
August 23, 2001
3. It is suggested that you develope a monthly spread sheet that will record daily operator
information. This daily -biweekly information could be; aeration basin dissolved oxygen, 30
minute settable solids, aeration basin miss, (RAS) return activated sludge (mg/1), clarifier
blanket levels, waste activated sludge (g.p.d.), just to name a few items of interest. I would also
recommend that the MCRT(mean cell residence time) be used to determine the pounds to be
wasted from the system each day.
4. I would highly recommend that a high level alainr be installed on the influent pumps wetwell
to alert on call personnel if activated. This is especially needed since the plant is not staffed but
8 hours per day and only on the week days.
5. The sludge storage basin has not has been cleaned since 1997. The basin is supernanted back
into the treatment plant to provide room for additional solids to be wasted. I was told the sludge
is so thick that it can't be decanted much longer. It is critical for the continued compliant
operation of this treatment plant, that the basin be cleaned immediately.
Thank you for the time that you spent with us. I hope that it was beneficial and I look forward to
a follow-up visit in the future. If I can be of further assistance, I can be reached at the
Fayetteville Regional Office at 910-486-1541.
r
Don Register
Environmental Technician IV
cc: Mayor Livingston Lewis
David McKew
FRO files
Operator Training and Certification, Tony Arnold