NC0043532_NOV-2021-LV-0597 Response_20210823

STANLY COUNTY
NORTH CAROLINA
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August 23, 2021
Mr. Roberto Sheller
NCDEQ Mooresville Regional Office
610 East Center Avenue Suite 301
Mooresville, NC 29202
Re: Subject:
Notice of Violation and Intent to Assess Civil Penalty
Tracking No: NOV- 2021-LV-0597
Permit No. NC 0043532
West Stanly WWTP
Stanly County
In response to Limit Exceedance Violation(s) 002 Effluent Nitrogen, Ammonia Total NH3 dated
8/13/2021: Stanly County WWTP currently is under Special Order of Consent (SOC) and is
currently under construction since January 2021. The Limit Exceedance Violation listed in this
NOV is believed to be direct result of construction damage to aeration power lines. March 2 ,
2021 Haren Construction saw cut live power lines to the aeration treatment basins. This resulted
in total loss of aeration to WWTP facility from approximately 0800 — 2230 March 2, 2021. The
result of this incident was poor nitrification for several weeks afterward and throughout June
2021. This incident and lingering effluent ammonia NH3 levels prompted operations at West
Stanly WWTP to assess equipment and processes to remedy this issue. In addition to the damage
of aeration in March 2021, WSWWTP operations personnel found aerators were under
performing due to excessive wear on propeller blades. The worn blades were unable to disperse
enough water volume needed for nitrification ammonia reduction. Parts were ordered to make
these repairs and as of the date of this letter all repairs have been made and WSWWTP ammonia
NH3 levels are in compliance.
002 Effluent Nitrogen, Ammonia Total (as N)- Concentration (C0610) 6/5/21, Limit Value 9,
Reported value 38.33 Weekly
002 Effluent BOD, 5-Day (20 Deg. C) — Concentration (C0310) 6/12/21, Limit Value 13.5,
Reported Value 22.73 Weekly *2.5" rain I/I, on June 8/2021 Effluent flow surge to 1.094 MGD
Utilities Department 1000 N. First Street, Suite 12, Albemarle, NC28001
P/ 704.986.3686 www.stanlycountyncgov F/ 704.986.3711

STANLY COUNTY
NORTH CAROLINA
W tew 74, /aac(, Lece e,
002 Effluent Nitrogen, Ammonia Total (as N)- Concentration (C0610) 6/12/21, Limit Value 9,
Reported value 14.77 Weekly
002 Effluent BOD, 5-Day (20 Deg. C) — Concentration (C0310) 6/30/21, Limit Value 9,
Reported Value 10.44 Monthly
002 Effluent Nitrogen, Ammonia Total (as N)- Concentration (C0610) 6/30/21, Limit Value 3,
Reported value 12.61 Monthly
We do believe we have turned the corner with regards to replacement of aerator impeller in the
month of July 2021 and future result should be in compliance. If you have any additional
comments, concerns or advice please do not hesitate to contact via email or phone numbers
provided below.
Respectfully,
Duane Wingo
Duane Wingo, PE
Stanly County Utilities Director
1000 N. First Street Suite 12 Albemarle, NC 28001
Phone: [phone]
Cell: [phone]
dwingo(ustanlvcountync.gov
Cc: Tommy Gibbons File: 631 (07) 2021 LV-2021-0597
Utilities Department 1000 N. First Street, Suite 12, Albemarle, NC28001
P/ 704.986.3686 www.stanlycountyncgov F/ 704.986.3711