NC0081621_By-pass of treatment_20201118

Strickland, Bev
From:
Carson, Bonnie <[e-mail]>
Sent:
Wednesday, November 18, 2020 1:53 PM
To:
Scheller, Roberto
Cc:
Sims, James; Holt, Kim
Subject:
[External] NPDES 0081621 MUDDY CREEK WWTP - Manhole Overflow
Attachments:
NPDES 0081621 MCWWTP - Manhole Overflow.pdf
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Roberto,
Please find attached an electronic copy of the subject report/memo for your information. The original
document is being sent to you via U.S. mail -certified. Should you have questions/concerns, please contact Kim
Holt at [e-mail] or by calling 704-888-4888, 980-521-8611. Thank you!
Bonnie Carson
Rocky River Regional WWTP, 6400 Breezy Lane, Concord, NC 28025
[phone], ext. 110, Al [phone]
WSACC-
30iQQ09 0. NC Stf Pu* U& * 0450012010
1

IS014001:2015 ♦ NC SharPubicSacior � ISO45001:2018
CERTIFIED MAIL
RETURN RECEIPT REQUESTED
November 16, 2020
Mr. Roberto Scheller(roberto.scheller(a�ncdenr.gov_)
Division of Water Resources
Water Quality Regional Operations Section
610 E. Center Avenue, Suite 301
Mooresville, N.C. 28115
SUBJECT: NPDES PERMIT- NC0081621
MANHOLE OVERFLOW
MUDDY CREEK WWTP
CABARRUS COUNTY, NORTH CAROLINA
Dear Mr. Scheller:
WATER & SEWER AUTHORITY
OF CABARRUS COUNTY
Administrative Offices
232 Davidson Hwy, Concord, NC 28027
704.786.1783 ♦ 704,795,1564 Fax
Rocky River Regional WWTP
6400 Breezy Lane, Concord, NC 28025
704.788.4164 ♦ 704.786,1967 Fax
www.wsacc.org
This letter is a follow-up to the phone conversation I had with Mr. Wes Bell on November 12, 2020
at 4:31 p.m0 regarding a manhole overflow. I notified Mr. Bell of the overflow inside of the Muddy
Creek Wastewater Treatment Plant (MCWWTP) and the plan to open the disk filter bypass valve.
The overflow was discovered at 2:00 p.m. during a plant walls through. I inspected the clarifiers
which provides the flow through manhole 15 and found that the level of the water was over the
weirs. After inspecting the disk filters, which is the next step in the process, it was found that all 3
filters were flowing over the overflow baffle. I immediately lowered the flow rate coming out of
the EQ basin to allow the clarifier levels to drop and stop manhole 15 from continuing to overflow.
By 2:15 p.m., the overflow from manhole 15 had ceased. I estimate approximately 20-30 gallons of
supernatant came up through manhole 15 and spilled onto the ground.
The MCWWTP received three inches of rain on November 12, 2020. The flow coming into the
plant was at a rate higher than the plant could accommodate. For this reason the decision was made
to open the valve that bypasses the disk filters and to allow the water from the clarifiers to flow to
the disk filters as well as straight to the UV system. Initially the bypass valve was opened at 5:25
p.m. on November 12 and was closed at 4:00 a.m., November 13. The bypass valve remained
closed until 9:30 a.m., November 13 when the wet well, at the Main Pumping Station began to
rapidly fill again due to increased flow to the plant. The valve remained opened until 4:50 a.m.,
November 14. In total the MCWWTP operated with the disk filter bypass valve open for 29.92
hours. Please note an operator was onsite during the entire time the bypass valve was open.

Page 2
Mr. Scheller
November 16, 2020
If you have any additional questions or concerns, I maybe reached at 704-888-4888, 980-521-8611,
or via email KimHoltawsacc.org.
KH/blc
Sincerely,
Kimberly Holt
Muddy Creek WWTP ORC
cc: James Sims, WSACC
File