NC0026573_NOVNOI-2023-LV-0612_resp_20230911

City of Morganton
Water Resources Department
September 1 lth, 2023
Daniel Boss, Assistant Regional Supervisor
Water Quality Regional Operations Section
Asheville Regional Office
Division of Water Resources, NCDEQ
Subject: NOV Response to NOV-2023-LV-0612
Dear Mr. Boss,
We have reviewed the permit violation NOV-2023-LV-0612 for Permit #NC0026573
concerning the weekly TSS violation.
For the week of July 3rd - 7th, the facility experienced several issues which lead to the
violation. The facility experienced some upset with low pH and had secondary sludge blankets
rise to the surface (sludge flipping) causing elevated TSS results on the 3rd. Facility mitigated as
much as possible over Sunday the 2nd and Monday the 3rd by taking clarifiers offline, and
turning off aeration blowers to allow sludge to successfully flip in aeration basin instead of in the
secondary clarifiers. Sludge flipping has happened several times over the past several years and
facility is still inconclusive of the reason. Suspect is from draining EQ basins that has a negative
impact on system.
On July 5th, secondary clarifier #2 had to be taken offline to begin draining due to a
mechanical issue, a baffle wall got bent and scum arm unable to make revolutions which
rendered clarifier unusable until repairs were made the following week.
Later on July 5th there was a bad thunderstorm centered over Morganton area that
dumped over 3.5 inches of rain over a 2-3 hour period referencing NOAA website. This caused
local issues including a sewer lift station SSO. Facility had 18 MGD peak of flow for several
hours early Thursday morning from the rain event. Facility put all available tanks online but
were unable to utilize SC#2 so we had less capacity to take on the flow. Due to this, we
experienced hydraulic overloading once EQ storage filled. The week also had a holiday which
meant one less day to use for the weekly averages. A notifying of violation email was sent to you
and Melanie Kemp on July 71h with similar details.
If there is any questions or if more information is needed, please reach me at
828-438-5375 or at [e-mail]
Sincerely,
Eli Self
Wastewater Plant Superintendent & ORC
City of Morganton, NC
Telephone [phone] East Union St. Post Office Box 3448
www.morgantonNC.gov Morganton, NC 28655 Morganton, NC 28680-3448