NC0055786_202308PCI_Cover Letter_20230815

ROY COOPER
Governor
ELIZABETH S. BISER
Secretary
RICHARD E. ROGERS, JR.
Director
Will Hodges
Wastewater Treatment Plant Supervisor
City of Lexington
28 W. Center Street
Lexington, NC 27292-3099
NORTH CAROLINA
Environmental Quality
August 15, 2023
SUBJECT: Pretreatment Compliance Inspection (PCI)
Lexington Regional WWTP
Main Program Permit (NPDES) #NC0055786
Davidson County
Dear Mr. Hodges:
On August 8, 2023, a Pretreatment Compliance Inspection (PCI) was performed by Tricia Lowery of the
Winston-Salem Regional Office. Eglantina Minerali was present for the inspection. The purpose of this
inspection was to determine the effectiveness of the City's pretreatment program, which includes
reviewing the files, POTW plant performance, industry monitoring data, and adherence to the
enforcement response plan (ERP).
Background
This is 6.5 MGD permitted facility. The City of Lexington has 6 Significant Industrial Users (SIUs), 5 of
which are categorical.
POTW Interview
There have been several NPDES violations concerning BOD and ammonia limits. Violations occurred in
September and October 2022 which did not result in NOVs. Additional violation occurred in March, April,
May, and June 2023 concerning BOD and ammonia. These violations resulted in NOV (March 2023) and
NOV w/ intent (April/May 2023). June 2023 violation is currently in review. Jesse Barnes and Gary
Hudson conducted a technical assistance visit on August 4, 2023. Preliminary report indicates the
possibility of insufficient aeration (DO levels) in aeration basin due to malfunctioning diffusers.
Eggar Wood Products was issued a NOV for silver limit violation in June 2023. It was an isolated incident
and no further issues. Control Authority could not determine with certainty what caused elevation in silver.
POTW has a contract with Davidson County to intake 500,000 mgd. The contract was recently updated.
Pretreatment Program Elements Review
The Headworks Analysis (HWA) was last approved on 7/16/2020. The next HWA is due 7/1/2024.
DffNorth Carolina Department of Environmental Quality I Division of Water Resources
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Winston-Salem Regional Office 1 450 W. Hanes Mill Rd, Suite 300 I Winston-Salem, North Carolina 27105
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The IWS was last approved on 12/2/2020. The next IWS is due 11/223/2025.
The Sewer Use Ordinance (SUO) was approved on 1/9/2013.
The Enforcement Response Plan (ERP) was submitted on 2/3/2020 and approved on 2/13/2020.
The Long -Term Monitoring Plan (LTMP) was submitted 9/24/2020 and approved on 3/11/2021.
LTMP File Review
The Long -Term Monitoring Plan (LTMP) is being conducted at the proper locations and frequencies
(2/year).
Industrial User Permit (IUP) File Review
A review of the file for Eggar (#0114) revealed that the monitoring data was well organized and
compliant.
A review of the file for ASCO (#0038) revealed that the monitoring data was well organized and
compliant.
A review of the file for Metcor (#0012) revealed that the monitoring data was well organized and
compliant.
Action Items
No other action items were noted.
The pretreatment program is considered satisfactory. Ms. Minerali runs an adequate pretreatment program.
If you have any questions, please contact Tricia Lowery or me at [phone].
Sincerely,
DocuSiiggned by:
145B49E225C94EA...
Lon T. Snider
Regional Supervisor
Water Quality Regional Operations Section
Division of Water Resources, NCDEQ — WSRO
Attachment:
1. NC DWR Pretreatment Compliance Inspection (PCI) Report
REQ� North Carolina Department ofEnvironmental Quality I Division ofWater Resources
Winston-Salem Regional Office 1 450 W. Hanes Mill Rd, Suite 300 1 Raleigh, North Carolina 27105
NORTH CAROLINA 336.776.9800
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