NC0020184_Correspondence_20221017

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we are TRtt to our customers!
October 7, 2022
Mr. Ori Tuvia
Division of Water Quality, Mooresville Regional Office
610 East Center Avenue, Suite 301
Mooresville, NC 28115
RE: Notice of Violation/Notice of Recommendation for Enforcement
Violation of G.S. 143-215.1(a)
Unpermitted Discharge of Wastewater
Tracking #: NOV-2022-DV-0280
NPDES Permit No. NC0020184
Two Rivers Utilities/Long Creek WWTP
Gaston County
Dear Mr. Tuvia:
Two Rivers Utilities received the above referenced Notice of Violation regarding an interruption in the chlorination process at the
Long Creek WWTP effluent that occurred on September 19, 2022, and is providing the following additional information to clarify the
events that occurred.
As discussed earlier, the Long Creek WWTP experienced a leak from the internal reuse water piping which necessitated an
emergency shut down of the internal reuse water system that resulted in the discharge of plant effluent that was not fully
disinfected.
Initially, Two Rivers Utilities' maintenance staff was replacing an inoperable check valve on the internal reuse water system. The
reuse water system has redundant pumps with separate check valves, so the operational plan was to use the redundant reuse
pump and valve for chemical feed and other uses within the treatment plant. At 1305 on 9/19/2022, after the old check valve was
removed the piping for the reuse system shifted significantly and unexpectedly, causing a leak in a mega lug pipe joint which is
common to both pumps. An estimated 400 gallons of reuse water (chlorinated and dechlorinated plant effluent) leaked onto the
ground and partway down rip -rap of a stormwater outfall. It did not reach surface water. The reuse water flow was turned off
approximately 5 minutes after the leak started in order to repair the piping.
The internal reuse water is used as carrier water to feed chlorine and sulfur dioxide for disinfection and dechlorination. The plant
does not have a potable water supply capable of providing the volume of water necessary to deliver chlorine and sulfur dioxide to
the process. The chlorine contact basin will maintain chlorine residual for approximately an hour after chlorine feed stops. No
visible chlorine was detectable in the chlorine contact basin when checked at approximately 1500.
Maintenance staff worked diligently to repair the piping system so that the reuse water system could be restarted and the new
check valve put in place. It was a difficult process that required some time. At 1520 the internal reuse system was back on line and
chlorine was feeding. At 1525 chlorine was detected in the chlorine contact basin.
Based on the flow for the day and an estimate of 1.25 hours of discharge without chlorine in the contact basin, it is believed that
275,000 gallons was discharged into the South Fork Catawba River without full disinfection.

Internal Reuse Water Pumping System at Long Creek WWTP:
Redundant pump
Check Valve that was
being replaced
Common Pipe that
twisted and started
leaking.
Due to this event, fecal coliform sampling was conducted at the upstream and both downstream sampling locations. Results are as
follows:
Upstream sampled 9/19/22 at 1600 = 1074 cfu/100mL
Downstream D1 sampled 9/19/22 at 1613 = 1261 cfu/100mL
Downstream D2 sampled 9/19/22 at 1634 = 180 cfu/100mL
After a thorough review of this incident with all appropriate staff, it was determined that during future similar projects, additional
efforts will be taken to secure the piping. The review also indicates it would have been possible to divert influent flow into an
empty basin, thereby ceasing effluent flow while the piping was repaired. The operations staff who were on site are relatively new
and lacked the detailed knowledge and experience to take this action. By the time an experienced staff member was contacted for
input, the piping repair was completed. All Plant Operators have since been trained in detail on mitigating actions that must be
taken during future similar incidents. This training included hands-on, field training for all staff. Additionally, the potential for
similar incidents is being reviewed. Where appropriate, necessary instructions will be added to existing standard operating
procedures and/or incorporated into staff training.
Please advise if NCDEQ wishes to receive any additional information or future updates regarding this incident or follow up actions.
Two Rivers Utilities regrets this instance of non-compliance and strives to meet all permit conditions and requirements. If additional
information is needed, please contact me at 704-866-6726 or [e-mail].
Sincerely,
1
Stephanie B. Scheringer
Division Manager Wastewater Treatment
cc:
Andrew Pitner — Assistant Regional Supervisor, NCDEQ
Mourice Brothers — Treatment Plant Supervisor/ORC — Long Creek WWTP
Certified Mail: 7017 0530 0000 9533 2401