NC0021733_Staff Comments_20220826

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ROY COOPER
Governor
ELIZABETH S. BISER
Secretary
RICHARD E. ROGERS, JR. NORTH CAROLINA
Director Environmental Quality
Town of Marshall 8/26/2022
Attn: Don Byers, Pretreatment Coordinator
P.O. Box 548
Marshall, NC 28753
Email: [e-mail]
Subject: HWA-AT and STMP Review
Program Name: Marshall
NPDES Permit No. NC0021733, 0.4 MGD
Landfill Permit No. SNL 32-0280
Madison County, ARO
Dear Permittee:
The Municipal Unit of the Division of Water Resources is currently reviewing the Headworks
Analysis (HWA) and allocation table (AT) for the Town of Marshall's wastewater treatment plant
(WWTP) working under the NPDES Permit No NC0021733 (effective on July 1, 2022). The HWA
was initially received by the Division on February 27, 2021, followed by more information
received on June 22, 2022. We regret the delay in providing this review.
Please review the corrections and observations, and address the requests discussed below in
the enclosed spreadsheet. Please follow the color code in the spreadsheet and submit a cover letter
outlining the main changes. Please submit the updated HWA-AT and supporting documents and
the updated Short -Term Monitoring Plan (STMP) by December 28, 2022.
1. HWA Corrections
a. POTW Average Flow was updated from 0.06 to 0.08 based on the average annual flow
for the last three years.
b. Water Quality Stream Standards: The HWA was updated to use site -specific water
quality standards (WQS) for arsenic, cadmium, chromium, copper, cyanide, lead,
molybdenum, nickel, silver, and zinc (Source: `RPA Input (WQS)' Tab in the HWA
Sheet).
c. Uncontrolled (formerly Uncontrollable) values were corrected to match the mass
balance values. Please correct these values in your uncontrolled spreadsheet.
2. HWA Requests
a. Please provide the Facility's Design Criteria documentation.
b. Please revise the SIU Uncontrolled Mass Balance Spreadsheet to ensure that the
uncontrolled concentration for molybdenum and selenium to be used in the HWA
(mg/L) matches any of the available values (mass balance or literature).
3. AT Corrections
a. Allocation Table (AT): In the HWA review process, the Permittee renewed the
Industrial User Permit (IUP) for Derringer-Ney. The AT has been updated to reflect
those changes and include all limits in the permit.
4. STMP Observations and Requests
a. Review pollutants of concern (POCs) and update the STMP to reflect pollutants in
industrial user permits (IUPs).

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b. The target Practical Quantification Level (PQLs) for the following parameter shall be
updated in the STMP: silver (from 5.0 to 1.0 µg/1)
c. The Division recommends updating the PQL for the following parameters in the
STMP: arsenic (from 10 to 2.0 µg/1), cadmium (from 2 to 0.5 µg/1), lead (from 10 to
2.0 µg/1), molybdenum (from 100 to 10.0 µg/1), and nickel (from 10 to 5.0 µg/1).
d. Ensure all PQLs listed include the corresponding units of measurement.
e. Please include a revision history section for the STMP.
Federal and State pretreatment regulations require the local delegated pretreatment program to
effectively control and document the discharge of wastewater from Significant/Categorical
Industrial Users to the POTW. It is the POTW's responsibility to ensure that these objectives are
consistently met.
Thank you for your continued support of the Pretreatment Program. If you have any questions or
comments, please contact the Pretreatment Coordinator Keyes [[e-mail]], or the
Unit Supervisor, Michael at [[e-mail]].
Sincerely,
DocuSigned by:
-C464531431644FE...
for Richard E. Rogers Jr., Director
Division of Water Resources
dy/Marshall.21733_hwa.review_2022
Attachments:
Marshall.21733.HWA-AT(under review)
cc with attachments:
DWR Asheville Regional Office — Pretreatment/ Dan Boss
Municipal Unit File and Central Files (Laserfiche)