NC0025496_Staff Comments_20220829

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ROY COOPER
Governor
ELIZABETH S. BISER
Secretary
RICHARD E. ROGERS, JR.
Director
NORTH CAROLINA
Environmental Quality
8/29/2022
City of Lincolnton
Attn: Daniel Perry, Pretreatment Coordinator
P.O. Box 617
Lincolnton, NC 27093
Email: [e-mail]
Subject: HWA-AT and LTMP Review
Program Name: Lincolnton
NPDES Permit No NC0025496, 3.5 MGD
Class B Biosolids Permit No. WQ0002712
City of Lincolnton WWTP
Lincoln County, MRO
Dear Permittee:
The Municipal Unit of the Division of Water Resources is currently reviewing the Headworks
Analysis (HWA) and Allocation Table (AT) for the City of Lincolnton' s wastewater treatment
plant (WWTP) working under the NPDES Permit No NC0025496 (effective on September 1,
2021). The HWA was initially received by the Division on May 27, 2022.
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 with supporting documents and
the updated Long -Term Monitoring Plan (LTMP) by September 30, 2022.
1. HWA Corrections
a. POTW NPDES Permitted Flow (MGD) was updated from 6.0 MGD to 3.5 MGD,
current permitted flow in the NPDES permit.
b. Water Quality Stream Standards: The HWA was updated to use site -specific water
quality standards (WQS) for cadmium, chromium, copper, lead, molybdenum, nickel,
selenium, silver, zinc, antimony, and bis (2-ethylhexyl) phthalate (Source: `RPA Input'
Tab in the HWA Sheet).
c. Oil & grease and TTO were POC delisted from the HWA table as they cannot be
evaluated using the standard HWA techniques. If the POTW has difficulty with these
parameters, then a specialized monitoring program must be established [Comprehensive
Guidance, Chapter 4, Section C]
d. Silver: The AT showed a calculated over allocation based on the dissolved metals stream
standard. Recently, DWR has decided to allow POTWs the option of using zero as
uncontrolled concentration and the use of the next most limiting factor (Acute WQS)
when all silver data is reported as below the best available PQL. All recent WWTP
influent and effluent silver data was below 1.0 ug/1. Therefore, the use of zero and site -
specific acute WQS is allowed.
2. HWA-AT Requests
a. Age of Sludge Site is a value used for informational purposes only, it is based on the
approximate permit life. Please revise the sludge permit life and update.
b. Sludge Site Life (yrs) used in the calculation a cumulative (lbs/acre) value of 28.996.
Please clarify the derivation of this value.

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c. Plant Removal Rate (%) calculation for Bis (2-Ethylhexyl) Phthalate is unclear in the
spreadsheet provided. Please revise.
d. If there are new SIUs or if changes in industrial discharges occurred since the HWA-
AT was submitted, please revise the uncontrolled concentrations (mg/L)
e. For any organic or pharmaceutical compound that is included in the LTMP or has shown
concerning detections, please include it in the HWA-AT Sheet
f. Cerium and Lanthanum were pollutants listed in the HWA table by the Facility. Please
clarify in the HWA Narrative and LTMP basis for the inclusion of these POC.
g. Please include either the site -specific value or the literature value of the Anaerobic
Digestor Inhibition Concentrations (mg/L). This value is needed to calculate the
Anaerobic Digestor Inhibition Loading (lbs/day) and develop an additional limiting
criteria for MAHL.
3. LTMP Observations and Requests
a. 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).
b. Ensure all POC limited by the NPDES permit, IUPs, and sludge permit are included
in the LTMP POC Table and sampling plan.
c. Please include a revision history section for the LTMP.
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,
�1 "DocuuSigned by:
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for Richard E. Rogers Jr., Director
Division of Water Resources
dy/Lincolnton.25496_hwa.review_2022
Attachments:
Lincolnton.25496. HWA-AT (under review) (.xlsx and .pdf)
cc with attachments:
City of Lincolnton, Superintendent/ Donald Burkey
DWR - Morresville Regional Office — Pretreatment/Wes Bell
Municipal Unit File and Central Files (Laserfiche)