NC0025453_NOV-2024-PC-0474 Response to Notice_20240829

August 29, 2024
Vaness E. Manuel
Assistant Regional Supervisor
Water Quality Regional Operations Section
Raleigh Regional Office
3800 Barrett Dr.
Raleigh NC, 27609
Re: Notice of Violation, Tracking Number: NOV-2024-PC-0474, Permit # NC0025453, Sam's Branch WRF (SWF),
Johnston County
Ibis. Manuel:
The Town of Clayton offers the following information regarding the NOV for the Unauthorized Bypass that occurred
the evening of 07/23/2024. This bypass is under incident number 202401212. This NOV is dated 08/08/2024 and was
received by the Town on 08/20/2024. At approximately 7:15pm on 07/23/24, the On -Call Operator responded to a
Power Outage at the WRF that caused the Aerators in the Oxidation Ditches to shut off during a thunderstorm event.
Once the Operator reset the aerators he checked other essential operating equipment at the plant. While checking
equipment the Operator found the backup effluent generator was running but the effluent pump station was down and
the wtwell containing treated effluent wastewater was bypassing. It was noted that the On -Call Dialer never called out
the Operator for the High Effluent Wetwell Alarm. It was also noted that the #2 Effluent Pump at the time (which is
typically set on bypass of the VFDs) was out of service and offsite for repair. The Operator responded quickly to the
situation and reset the VFDs of the effluent pumps. He found the VFDs of the pumps showed Overcurrent due to the
power outage caused by lightning in the area. Once power to the VFDs was cycled, the Operator was able to pump
down the effluent wetwell and the bypass ended at approximately 7:30pm. Approximately 17,700 gallons of treated
effluent bypassed the wetweil and spilled around the surrounding area. No flow was found to enter surface waters, and
no harmful environmental effects were found. The WRF was also compliant with its NPDES Parameter Limits during
this incident. The incident was reported to Michael Hall of DEQ on 07/24/2024 at 8:35am by David White and
received a call back from DEQ at 10:55am with the incident report number. The WWI? Bypass 5- Day Reporting form
for the incident was submitted by email to ?Vichael Hall on 07/25/2024 at 10:OOam.
In response to this bypass, the Town has conducted further preventative maintenance on the VFDs of the effluent
pumps. This preventive maintenance included increasing the cooldown timer setting of the effluent pumps VFDs to 90
seconds. In the event of another power outage, the effluent generator will come on and provide enough time for the
pumps to rev down to the allotted 381-1z in the VFDs before resetting. It was found the pumps were only revving down
to 45Hz. When the VFDs reset it would send too much power to the pumps which ultimately resulted in an
Overcurrent, tripping out the VFDs. Again, this issue has been identified and resolved. We also found the Call Out
Alarm for the Effluent High Wetwell had an old contactor that has since been replaced and tested. Lastly, as of
08/26/2024 our 42 Effluent Pump has been repaired, rewired, and put back in service at the WRF on bypass in the
event of another thunderstorm or rain event. The Town will continue to strive to prevent future incidents like this from
occurring in the future. Please contact me at (919)-594-0417 or email me at dwhite cr townofclaytonnc.org for any
questions or concerns.
Sincerely,
David White
Water Reclamation Superintendent
Town of Clayton, NC