NC0028037_Draft Permit_20240723

ROY COOPER
Goi,ernor
ELIZABETH BISER
Secretary
RICHARD E. ROGERS, JR
Director
Tom Johnson, Water Resources Director
City of Lexington
28 W Center Street
Lexington, North Carolina 27292
Mr. Johnson:
NORTH CAROLINA
Environmental Quality
July 23, 2024
Subject: Review of Permit - Renewal DRAFT
NPDES Permit NCO028037
Lexington [Combined] WTPs #1 & #2
WPCS Grade PC-1
Davidson County
The Division of Water Resources (DWR or the Division) received your application to renew the subject
NPDES permit on September 26, 2023, and we hereby transmit this draft permit for your review and
comment. Please review this draft carefully to ensure your understanding of its limits and monitoring
conditions, and to correct errors, if any.
Concurrent with this notification, the Division will solicit public comment on this draft by publishing a
notice in newspapers having circulation in the general Davidson County area, as required by the
NPDES Program. Please provide your written comments, if any, to me, Joe R. Corporon, P.G.
[e-mail]] no later than August 12, 2024 (approximately 30 days after receiving this
document). Your written comments are welcome, but they are not mandatory.
The Division understands from your application that Lexington WTP #1 & #2 (Lexington) combines the
discharge for both WTPs and that you have made no significant alterations to treatment systems or
processes since last renewal. We have therefore made only minimal updates to the renewal draft.
Change Summary / Updates to Previous Permit
• Turbidi — discontinued monitoring [receiving stream not impaired for turbidity]
• Total Zinc — discontinued; reasonable potential (RP) = no; [max predictable < 50% allowable].
• Total Copper — updated limits from previous (41.45 MA / 47.85 DM) to 21.9 MA / 28.6 DM, in
accord with RPA, monitoring increased from Monthly to 2/Month [NCAC 213 .0505].
• Total Copper — updated limits Schedule of Compliance for reporting [see permit section A. (4.)]
• undated footnote for Upstream Total Hardness monitoring [see A. (L), #5]
• uMRdated eDMR footnote [see A. (L), footnote #1 and language in Special Condition A. (5.)
• updated Facility Location Map
North Carolina Department of Environmental Quality I Division of Water Resources
512 North Salisbury Street 11617 Mail Service Center I Raleigh, North Carolina 27699-1617 — 919.707.9000

Tom Johnson, Water Resources Director
Permit Renewal - Draft Review 2024
Page 2 of 2
Factors for Eligibility - General Permit NCG590000:
• Lexington uses conventional treatment technology; therefore, they are eligible.
• Lexington has passed last 12 WET tests therefore by tox standards, they are eligible.
• Renewal adds permit limits for Total Copper therefore they are not eligible.
• Conclusion: Lexington WTP is not eligible for the NCG59 until after review of next
renewal application.
The NPDES Standard Conditions (Parts II, III, and IV), are part of this permit but are not included in
this draft document (cover, map, and Part I). The latest version of Parts II, III, and IV are available
at https://bit.ly/3k5NFaL and can be viewed online or downloaded as a PDF file.
If you have questions about any of the above, or about the attached permit, please email at
Ooe.corporon(a-,)deq.nc.gov] so that we may maintain a written record of our correspondence.
Sincerely,
sitting Unit
Enclosure: NPDES Permit NC0028037 (Renewal DRAFT)
ec: NPDES Program Files [Laserfiche]
WSRO, Gary Hudson [[e-mail]]
WSRO, Jenny Graznak [e-mail]]
DWR/OCU, Jeffery Talbott [e-mail]]
ATB, Molly Nicholson [[e-mail]]
Lexington WTP ORC: R.S. Walser [[e-mail]]

Permit NCO028037
STATE OF NORTH CAROLINA
DEPARTMENT OF ENVIRONMENTAL QUALITY
DIVISION OF WATER RESOURCES
PERMIT
TO DISCHARGE WASTEWATER UNDER THE
NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM
(NPDES)
In compliance with the provision of North Carolina General Statute 143-215.1, other lawful standards
and regulations promulgated and adopted by the North Carolina Environmental Management
Commission, and the Federal Water Pollution Q6ptrol Act, as amended,
City of Lexi*4
is hereby authorized to discharge wast6water f om a facility, located at the
Lexington Water Treatmenti�fit (WTP)'41 -& #2
2979 Old Greensboro Street Eit,�4sion, Lexington
Davidson Co nty
to receiving waters designated as Abbo4 Creek in the Yadkin -Pee Dee River Basin in accordance with
effluent limitations, monitoring requirements, and other applicable conditions set forth in Parts I, II, III
and IV hereof.
This permit shall become effective 2024.
This permit and authorization t�di� arge shall expire at midnight on February 28, 2028.
Signed this day , 2024.
John E. Hennessy, Section Chief
Water Quality Regional Operations
Division of Water Resources
By Authority of the Environmental Management Commission
Pagel of 7

Permit NCO028037
SUPPLEMENT TO PERMIT COVER SHEET
All previous NPDES Permits issued to this facility, whether for operation or discharge are hereby
revoked. As of this permit issuance, any previously issued permit bearing this number is no longer
effective. Therefore, the exclusive authority to operate and discharge from this facility arises under the
permit conditions, requirements, terms, and provisions included herein.
City of Lexington
is hereby authorized to:
1. continue to operate existing water treatment plants #1 and #2 [WPCS Grade PC-1] generating
potable water utilizing Conventional treatment technology [flocculation, sedimentation,
disinfection, filtration], each of two (2) generating effluent combined into one (1) discharge of
treated filter backwash rinsate/pond decant; a combined potable effluent of 9.4 MGD [design
capacity] generating a reported maximum monthly average flow, of 0.486 MGD; these treatment
system components consist of, but not lin#ted;to,
➢ two (2) each settling ponds (0.500 MG capacity), with 24=dour
gravity decant system and a sludge collection/draig system
➢ one (1) each pump station for sludge transfer
➢ four (4) each sludge drying beds [40ft x 40ft with collection drain
and pre -polymer -addition]
➢ one (1) each solids storage pad [concrete, .40ft x 60,7ft]
➢ one (1) each effluent meter with flow recorder
➢ one Q) each chlorine -contact chamber
➢ dechlorination
potential chemicals used -
o Alumini*sulfate o Zinc orthophosphate
o Powered aptivated carbon
o Potassium permanganate o Polymers
o Sodium hydroxide o Sodium hypochlorite
o Lime slurry o Sodium fluoride
o Sodium thiosulfate
these facilities located at 2979 Old Greensboro Street Extension, Lexington, Davidson County,
and
2 discharge from said treatment works via Outfall 001, at a location specified on the attached
map, into Abbotts Creek (Stream Segment 12-119-(4.5)], a waterbody currently classified
WS-III; CA waters within subbasin 03-07-07, [hydrological unit HUC: 030401030206] of the
Yadkin -Pee Dee River Basin.
Page 2 of 7

Permit NCO028037
Part I
A. (L) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS
[15A NCAC 02B .0400 et seq., 02B .0500 et seq., WPCS Grade PC-1]
During the period beginning on the effective date of this permit and lasting until expiration, the
Permittee is authorized to discharge filter backwash and pond decant via Outfall 001. Such discharges
shall be limited, monitored, and reported 1 by the Permittee as specified below:
EFFLUENT
CHARATERISTICS
[PCS Code]
LIMITS
MONITORING REQUIRMENTS
Monthly
Average
Daily
Maximum
Measurement
Frequency
Sample
Type
Sample
Location 2
Flow (MGD)
50050
1.994*
Continuous
Recorded
E
Total Suspended Solids
C0530
30 mg/L
45 mg/L
2/Month
Grab
E
pH (Standard Units)
00400
> 6.0 and
< 9.0 s.u.
2/Month
Grab
E
Total Residual Chlorine (TRC) 3
50060
1 28 µg/L
2/Month
Grab
E
Total Copper 4,6
01042
21.9 µg/L 4
28.6 µg/L 4
2/Month
Grab
E
Total Hardness (mg/L)
as CaCO3 or Ca + Mg)]
00900
Monitor and Report
Quarterly
Grab
5
E, U
Total Manganese 6 ( )
01055
Monitor and Report
Quarterly
Grab
E
Total Aluminum 6 W/O
01105
Monitor and Report
Quarterly
Grab
E
Total Phosphorus (TP) (m
00665
Monitor and Report
Quarterly`
Grab
E
Total Nitrogen (TM 7(mg/L)
00600
Monitor and Report
Quarterly
Grab
E
WET Test - Chronic 8
TG13313
Monitor and Report
Quarterly
Grab
E
* Limit = previous permit cycle's reported Maximum Monthly Averagg Flow.
Footnote:
1. Reporting -Beginning on the effective date of this permit, the Permittee shall submit discharge monitoring
reports electronically using NC DWI;N eDMR application system [see A. (3)].
2. Sampling - E = Effluent; U = Upstream, minimum 100 feet above the outfall, as practicable.
3. TRC - The Division shall consider compliant all effluent TRC values reported below 50 µg/L. However, the
Permittee shall continue to record and submit all values reported by North -Carolina certified test methods
(including field certified), even if these values fall below 50 µg/L.
4. See Section A. (4.) Schedule of Compliance
5. Upstream Total Hardness — If the Permittee joins as member of the Monitoring Coalition Program (the
Coalition), they may request to waive Upstream Hardness monitoring providing that the Coalition agrees to
sample at minimum Quarterly at their nearest upstream Monitoring Station. To waive monitoring
responsibility, the Permittee must submit written requests for approval to three (3) addressees; the
Coalition, the Winston-Salem Regional Office (WSRO), and NPDES Permitting [see Special Condition A.
(3.) ELECTRONIC REPORTING, #2. "How To Request a Waiver..."].
The Permittee must submit all Total Hardness test results with their next Permit Renewal Application. If the
Permittee terminates its Coalition membership, they shall immediately resume instream Hardness sampling and
reporting, and shall immediately notify WSRO and DWR / NPDES Permitting.
6. To assist in evaluating possible toxicity failure, monitor this parameter in conjunction with WET testing.
7. Total Nitrogen - For a given wastewater sample, TN = TKN + (NO2-N + NO3-N), where TN is Total
Nitrogen, (NO2-N + NO3-N) is Nitrite/Nitrate Nitrogen, and TKN is Total Kjeldahl Nitrogen.
8. Whole Effluent Toxicity (WET) testing — Chronic, using Ceriodaphnia duhia at effluent concentration of 52%
with samples collected in February, May, August, and November [see A. (2.)].
Page 3 of 7

Permit NCO028037
Conditions:
• Samples shall accurately characterize the physical and chemical properties of the discharge.
• The Permittee shall discharge no floating solids or foam visible in other than trace amounts.
A. (2.) CHRONIC TOXICITY MONITORING (QUARTERLY)
[15A NCAC 02B .0500 et seq.]
The permittee shall conduct Quarterly chronic toxicity tests using test procedures outlined in the "North Carolina
Ceriodaphnia Chronic Effluent Bioassay Procedure," Revised December 2010, or subsequent versions.
The effluent concentration defined as treatment two in the procedure document is 52%. The testing shall be
performed as a Ceriodaphnia dubia 7-day pass/fail test. The tests will be performed during the months of
February, May, August, and November. These months signify the first month of each three-month toxicity
testing quarter assigned to the facility. Effluent sampling for this testing must be obtained during representative
effluent discharge and shall be performed at the NPDES permitted final effluent discharge below all treatment
processes.
All toxicity testing results required as part of this permit condition will be entered on the Effluent Discharge
Monitoring Form (MR-1) for the month in which it was performed, using the parameter code TGP3B.
Additionally, DWR Form AT-1 (original) is to be sent to the following address:
Attention: North Carolina Division of Water Resources
Water Sciences Section/Aquatic Toxicology. Branch
1621 Mail Service Center
Raleigh, North Carolina 27699-1621
Or, results can be sent to the email, At\Forms.ATB(c)deq.nc.gov.
Completed Aquatic Toxicity Test Forms shall be filed with the Water Sciences Section no later than 30 days
after the end of the reporting period for which the report is made.
Test data shall be complete and accurate and include all supporting chemical/physical measurements performed
in association with the toxicity tests, as well as all dose/response data. Total residual chlorine of the effluent
toxicity sample must be measured and reported if chlorine is employed for disinfection of the waste stream.
Should there be no discharge of flow from the facility during a month in which toxicity monitoring is required,
the permittee will complete the information located at the top of the aquatic toxicity (AT) test form indicating
the facility name, permit number, pipe number, county, and the month/year of the report with the notation of
"No Flow" in the comment area of the form. The report shall be submitted to the Water Sciences Section at the
address cited above.
Should the permittee fail to monitor during a month in which toxicity monitoring is required, then monthly
monitoring will begin immediately. Upon submission of a valid test, this monthly test requirement will revert to
quarterly in the months specified above.
Should any test data from this monitoring requirement or tests performed by the North Carolina Division of
Water Resources indicate potential impacts to the receiving stream, this permit may be re -opened and modified
to include alternate monitoring requirements or limits.
NOTE: Failure to achieve test conditions as specified in the cited document, such as minimum control organism
survival, minimum control organism reproduction, and appropriate environmental controls, shall constitute an
invalid test and will require immediate follow-up testing to be completed no later than the last day of the month
following the month of the initial monitoring.
Page 4 of 7

Permit NCO028037
A. (3.) ELECTRONIC REPORTING OF DISCHARGE MONITORING REPORTS
[G.S. 143-215.1(b)]
Federal regulations require electronic submittal of all discharge monitoring reports (DMRs) and program
reports. The final NPDES Electronic Reporting Rule was adopted and became effective on December 21, 2015.
NOTE: This special condition supplements or supersedes the following sections within Part II of this permit
(Standard Conditions for NPDES Permits):
• Section B. (11.) Signatory Requirements
• Section D. (2.)
• Section D. (6.)
• Section E. (5.)
Reporting
Records Retention
Monitoring Reports
1. Reporting Requirements [Supersedes Section D. (2.) and Section E. (5.) (a)]
The permittee shall report discharge monitoring data electronically using the NC DWR's Electronic
Discharge Monitoring Report (eDMR) intemet application.
Monitoring results obtained during the previous month(s) shall be summarized for each month and
submitted electronically using eDMR. The eDMR system allows permitted facilities to enter monitoring
data and submit DMRs electronically using the internet. The eDMR system may be accessed at:
httns://deg.nc. gov/about/divisions/water-resources/edmr.
If a permittee is unable to use the eDMR system due to a demonstrated hardship or due to the facility being
physically located in an area where less than 10 percent of the households have broadband access, then a
temporary waiver from the NPDES electronic reporting requirements may be granted and discharge
monitoring data may be submitted on paper DMR forms (MR 1, 1. 1, 2, 3) or alternative forms approved by
the Director. Duplicate signed copies shall be submitted to the following address:
NC DEQ / Division of Water Resources / Water Quality Permitting Section
ATTENTION: Central Files
1617 Mail Service Center
Raleigh, North Carolina 27699-1617
See "How to Request a Waiver from Electronic Reporting" section below.
Monitoring results obtained during the previous month(s) shall be summarized for each month and reported
via the eDMR system no later than the last calendar day of the month following the completed reporting
period. Regardless of the submission method, the first DMR is due on the last day of the month following
the issuance of the permit or in the case of a new facility, on the last day of the month following the
commencement of discharge.
Starting on December 21, 2025, the permittee must electronically report the following compliance
monitoring data and reports, when applicable:
• Sewer Overflow/Bypass Event Reports;
• Pretreatment Program Annual Reports; and
• Clean Water Act (CWA) Section 316(b) Annual Reports.
The permittee may seek an electronic reporting waiver from the Division (see "How to Request a Waiver
from Electronic Reporting" section below).
Page 5 of 7

Permit NC0028037
Electronic Submissions
In accordance with 40 CFR 122.41(1)(9), the permittee must identify the initial recipient at the time of each
electronic submission. The permittee should use the EPA's website resources to identify the initial recipient
for the electronic submission.
Initial recipient of electronic NPDES information from NPDES-regulated facilities means the entity (EPA or
the state authorized by EPA to implement the NPDES program) that is the designated entity for receiving
electronic NPDES data [see 40 CFR 127.2(b)].
EPA plans to establish a website that will also link to the appropriate electronic reporting tool for each type
of electronic submission and for each state. Instructions on how to access and use the appropriate electronic
reporting tool will be available as well. Information on EPA's NPDES Electronic Reporting Rule is found
at: httt)s://www.federalregis�gov/documents/2015/10/22/2015-24954/national-pollutant-discharge-
elimination-system-nodes-electronic-reportine-rule
Electronic submissions must start by the dates listed in the "Reporting Requirements" section above.
2. How to Reauest a Waiver from Electronic Reporting
The permittee may seek a temporary electronic reporting waiver from the Division. To obtain an electronic
reporting waiver, a permittee must first submit an electronic reporting waiver request to the Division.
Requests for temporary electronic reporting waivers must be submitted in writing to the Division for written
approval at least sixty (60) days prior to the date the facility would be required under this permit to begin
submitting monitoring data and reports. The duration of a temporary waiver shall not exceed 5 years and
shall thereupon expire. At such time, monitoring data and reports shall be submitted electronically to the
Division unless the permittee re -applies for and is granted a new temporary electronic reporting waiver by
the Division. Approved electronic reporting waivers are not transferrable. Only penmittees with an
approved reporting waiver request may submit monitoring data and reports on paper to the Division for the
period that the approved reporting waiver request is effective.
Information on eDMR and the application for a temporary electronic reporting waiver are found on the
following web page: http//deg.nc.gov/about/divisions/water-resources/edmr
3. Signatory Requirements [Supplements Section B. (11.) (b) and Supersedes Section B. (11.) (d)1
All eDMRs submitted to the permit issuing authority shall be signed by a person described in Part II,
Section B. (I 1.)(a) or by a duly authorized representative of that person as described in Part II, Section B.
(I 1.)(b). A person, and not a position, must be delegated signatory authority for eDMR reporting purposes.
For eDMR submissions, the person signing and submitting the DMR must obtain an eDMR user account
and login credentials to access the eDMR system. For more information on North Carolina's eDMR
system, registering for eDMR and obtaining an eDMR user account, please visit the following web page:
http:// M.nc.gov/about/divisions/water-resources/edmr
Certification. Any person submitting an electronic DMR using the state's eDMR system shall make the
following certification [40 CFR 122.22]. NO OTHER STATEMENTS OF CERTIFICATION WILL BE
ACCEPTED:
"I certify, under penalty of law, that this document and all attachments were prepared under my direction or
supervision in accordance with a system designed to assure that qualified personnel properly gather and
evaluate the information submitted. Based on my inquiry of the person or persons who manage the system,
or those persons directly responsible for gathering the information, the information submitted is, to the best
of my knowledge and belief, true, accurate, and complete. I am aware that there are significant penalties for
submitting false information, including the possibility of fines and imprisonment for knowing violations. "
Page 6 of 7

Permit NCO028037
4. Records Retention (Supplements Section D. (631
The permittee shall retain records of all Discharge Monitoring Reports, including eDMR submissions.
These records or copies shall be maintained for a period of at least 3 years from the date of the report. This
period may be extended by the Director at any time [40 CFR 122.41].
A. (3.) SCHEDULE OF COMPLIANCE — TOTAL COPPER (Outfal1001)
[G. S. 143 -215. 1 (b)]
1. Within one (1) year from the permit effective date, the Permittee shall submit to the Division of Water
Resources a Corrective Action Plan (the Plan) summarizing actions and/or strategies to achieve
compliance with Total Copper limits at Outfall 001 [see A. (1.)]. The Permittee shall include specific
dates for completion or implementation of each proposed action.
2. Within two (2) years from the permit effective date, submit a report to the Division summarizing actions
taken in accordance with the Corrective Action Plan.
3. Within three (3) years from the effective date, submit a report to the Division summarizing
actions taken in accordance with the Corrective Action Plan.
4. Within four (4) years from the effective date, submit a report to the Division summarizing actions taken
in accordance with the Corrective Action Plan.
5. Within five (5) years from the permit effective date, the Pe�nittee shall achieve compliance with Total
Copper limits specified in Section A. (1.).
Upon the Division's approval of the Convective Action Plan, all reports and actions shall become an
enforceable part of this permit. If the Permittee requests to modify the Plan schedule or deadlines, they shall
submit to the Division a written request, at minimum ninety (90) days before a given Plan deadline.
Modification requests to exceed the Plan schedule by more than four (4) months are subject to Public Notice.
The Convective Action Plan and all reports shall include the permit owner's name (a person legally responsible
for the NPDES permit), the NPDES pen -nit number, and Pennittee's contact person.
Submit plan Modification requests to:
1) NCDEQ / Division of Water Resources
NPDiS'Compliance and Expedited Permitting
1617 Mail Service Center
Raleigh, NC 27699- 1617
2) NCDEQ / Division of Water Resources
Winston- Salem Regional Office
450 West Hanes Mill Road, Suite 300
Winston- Salem, NC 27105
A. (4.) NUTIENT REOPENER FOR HIGH ROCK LAKE
[G. S. 143- 215. 1(b)]
The Division of Water Resources may reopen this permit and/or modified it to implement nutrient requirements
in accordance with any future TMDL and/or nutrient management strategy for High Rock Lake.
Page 7 of 7

7
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Lexington WTPs #1&#2
(Outfall 001 — flows S)
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City of Lexington Facility
Lexington WTPs #1 & #2 Location
not to scale
Drainage Basin: Yadkin -Pee Dee Receiving Stream: Abbotts Creek
Latitude: 35° 5 V 17" N USGS Ouad: Lexington East, NC
longitude: 80° 11' 01" w Stream Segment: 12-1 19-(4.5)
Subbasin: 03-07-07 Stream Class: ws-111; CA NPDES Permit NCO028037
HUC: 030401020306 North Davidson County