NC0028037_Draft Permit_20141008

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NCDENR
North Carolina Department of Environment and Natural Resources
Pat McCrory
Governor
Roger Spach
Superintendent
City of Lexington
28 West Center Street
Lexington, NC 27292
Dear Mr. Spach:
John E. Skvarla, III
Secretary
October 8, 2014
Subject: Draft of NPDES Permit
Permit NCO028037
Lexington WTP #1 and #2
Davidson County
Class II
Enclosed with this letter is a copy of the renewal draft permit for your facility. Be aware there
are many changes from your existing permit. Please review the draft carefully to understand the
conditions, measurement units, and new requirements.
Proposed federal regulations require electronic submittal of all discharge monitoring reports
(DMRs) and specify that, if a state does not establish a system to receive such submittals, then
Permittees must submit DMRs electronically to the Environmental Protection Agency (EPA). The
Division anticipates that these regulations will be adopted and is beginning implementation.
The requirement to begin reporting discharge monitoring data electronically using the NC
DWR's Electronic Discharge Monitoring Report (eDMR) internet application has been added to this
permit. For information on eDMR, registering for eDMR and obtaining an eDMR user account, please
visit the following web page:
http://portal.ncdenr.org/web/wq/admin/bog/ipu/edmr.
For information on EPA's proposed NPDES Electronic Reporting Rule, please visit the following web
site:
http://www2.epa.gov/compliance/proposed-npdes-electronic-reporting-rule.
1617 Mail Service Center, Raleigh, North Carolina 27699-1617
Phone: [phone] Internet: www.ncwaterquality.org
An Equal Opportunity\Atfirmative Action Employer

Roger Spach, Superintendent
October 8, 2014
Page 2 of 3
A review of upstream and downstream turbidity data showed five exceedances of the Water
Quality Standard (WQS). As a result, effluent turbidity monitoring with a 50 NTU daily limit was
implemented in this permit. This replaces the previous requirements for upstream and downstream
sampling and applies the limit directly to the effluent. The Permittee may desire to continue sampling
turbidity upstream and downstream in order to assess whether the turbidity WQS was exceeded due to
natural background levels or not. Without this information, effluent turbidity reported to be greater
than 50 NTU will be assumed to be a WQS violation.
A summary of all the changes from your current permit are as follows:
1) Flow limit, calcium and magnesium monitoring was removed. In accordance with the 2009
Water Treatment Plant (WTP) NPDES Strategy, the flow limitation was removed along with
monitoring for calcium and magnesium [See A.(1.)].
2) Fluoride monitoring was removed. Fluoride effluent data showed no reasonable potential to
violate state water quality standards. Therefore, since the predicted value is less than 50% of
the water quality standard, in accordance with the July 2010 NPDES Monitoring frequency
memo, fluoride monitoring was removed [See A.(1.)].
3) Total iron monitoring was removed. No iron additives are used and there is no reasonable
potential to exceed the water quality standard so monitoring was removed [See A.(1.)].
4) Total copper and total zinc monitoring was reduced to quarterly to coincide with toxicity
testing. Reported total copper and total zinc effluent values violated water quality standards.
Both of these parameters have action level standards and are reviewed in conjunction with
toxicity test results. The facility has passed all toxicity tests for the last 5 years so copper and
zinc limitations are not necessary. However, since the reported values exceed their water
quality standards, in accordance with the July 2010 NPDES Monitoring frequency memo,
monitoring will remain [See A.(1.)].
5) Effluent turbidity twice per month monitoring with a 50 NTU daily limit was added. Instream
turbidity monitoring will be removed. As discussed above an effluent turbidity limit was
implemented in this permit [See A.(1.)].
6) Manganese limit was added with compliance to commence 48 months after the effective date of
this permit. Reported manganese values violated the water quality standard, however, the
manganese water quality standard is currently under review and proposed to be removed. A
compliance date 48 months from this permit effective date was established to postponed
implementation pending final resolution of the water quality standard [See A.(1.)].
7) Electronic Reporting of Discharge Monitoring Reports special condition and footnote was
added. To meet future US EPA electronic reporting requirements, electronic reporting special condition
and footnote with a compliance date no later than 270 dates from the final permit effective date was
implemented in this permit. [See A.(1.) and Special Condition A.(3.)]
8) High Rock Lake nutrient reopener special condition was added. As a discharge upstream of
High Rock Lake, a reopener special condition for future nutrient requirements was
implemented in this permit [See Special Condition A.(4.)].
9) Chronic toxicity special condition and Supplement to Permit Cover Sheet narratives was
updated. Technical corrections to address narrative changes, including correcting the chronic
test concentration to 21%, were implemented in this permit. [See Supplement to Permit Cover
Sheet Permit and Special Condition A.(2.)]

Roger Spach, Superintendent
October 8, 2014
Page 3 of 3
Concurrent with this notification the Division is publishing a notice in the newspaper having
circulation in the general Davidson County area, soliciting public comments on this permit draft.
Please provide any comments you may have regarding this draft to DENR — DWR, NPDES Program
no later than 30 days after receiving this draft permit.
Following the 30-day public comment period, the Division will review all pertinent comments
and take appropriate action prior to issuing a final permit. If you have questions concerning the draft
for your facility, please call Ron Berry at [phone] or by email at [e-mail].
If no adverse comments are received from the public or from you, this permit will likely be
issued in November 2014, with an effective date of January 1, 2015, expiring on April 30, 2019.
Sincerely,
ORIGINAL SIGNED BY RON BERRY
Ron Berry, Environmental Engineer
Division of Water Resources, NCDENR
Attachments
Cc: Winston-Salem Regional Office/Water Quality Programs (email with Fact Sheet)
WSS/Aquatic Toxicology Branch/Susan Meadows (email)
PWSS/Eric Hudson (email with Fact Sheet and approval form)
Steve Reid (email)
NPDES File

Permit NC0028037
STATE OF NORTH CAROLINA
DEPARTMENT OF ENVIRONMENT AND NATURAL RESOURCES
DIVISION OF WATER RESOURCES
DRAFT PERMIT
TO DISCHARGE WASTEWATER UNDER THE
NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM
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 Control Act, as amended,
City of Lexington
is hereby authorized to discharge wastewater from a facility located at the
Lexington Water Treatment Plant (WTP) 91 & #2
2979 Greensboro Street Extension
Lexington
Davidson County
to receiving waters designated as Abbotts 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 .................................... tbd.
This permit and authorization to discharge shall expire at midnight on April, 30, 2019.
Signed this day ............... tbd.
Thomas A. Reeder, Director
Division of Water Resources
By Authority of the Environmental Management Commission
Page 1 of 6

Permit NC0028037
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.
The City of Lexington
is hereby authorized to:
1. Continue to operate existing Conventional water treatment plants #1 and #2 with a
combined/single discharge of treated filter backwash/rinse from settling lagoons and final sand
filter drying beds. The two potable water treatment plants currently have a combined design
capacity of 9.4 MGD and a single maximum, monthly average treated wastewater discharge of
0.486 MGD. Wastewater treatment components consist of:
➢ Two (2) 0.5 MG 24-hour settling ponds with gravity decant system and
sludge collection/drain system
➢ Sludge transfer pump station
➢ Four (4) 40 ft x 40 ft sludge drying beds with collection drain and pre -
polymer addition
➢ 40 X 60 foot concrete solids storage pad
➢ Effluent meter with recorder
➢ Dechloronation
➢ Chemical used in facilities:
o Aluminum sulfate
o Powered activated carbon
o Potassium permanganate
o Sodium hydroxide
o Lime slurry
o Zinc orthophosphate
o Polymers
o Sodium hypochlorite
o Sodium fluoride
o Sodium thiosulfate
The facility is at the Lexington WTP #1 & #2 located at 2979 Greensboro Street Extension,
Lexington, Davidson County.
2 Discharge from said treatment works at the location specified on the attached map into
Abbotts Creek, classified as WS-III; CA waters in the Yadkin -Pee Dee River Basin.
Page 2 of 6

Permit NCO028037
Part I
A. (L) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS
a. During the period beginning on the effective date of this permit and lasting until expiration, the
Permittee is authorized to discharge filter backwash from Outfall 001. Such discharges shall be
limited and monitored' by the
Permittee asspecified below:
§CPI( YY3 P tr t
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t IL
AtM
Flow, MGD
Continuous
Recorded
Effluent
TSS
30 m L 45 m L
2/Month
Grab
Effluent
Not less than 6.0 S.U. nor
pH
2/Month
Grab
Effluent
eater than 9.0 S.U.
Total Residual Chlorine (TRC)
28 L
2/Month
Grab
Effluent
Turbidity
50 NTU
2/Month
Grab
Effluent
Manganese
970
Monthly
Grab
Effluent
Aluminum,
Quarterly
Grab
Effluent
Total Copper, L 4
Quarterly
Grab
Effluent
Total Zinc,µ
Quarterly
Grab
Effluent
Total Phosphorus, m
Quarterly
Grab
Effluent
Total Nitrogen, m (TN)
Quarterly
Grab
Effluent
Chronic Toxicity'
Quarterly
Grab
Effluent
Footnote:
1. No later than 270 days from the effective date of this permit, begin submitting discharge
monitoring reports electronically using NC DWR's eDMR application system. See Special
Condition A.(3.).
2. The Division shall consider all effluent TRC values reported below 50 ug/L to be in compliance with
the permit. However, the Permittee shall continue to record and submit all values reported by a North
Carolina certified laboratory (including field certified), even if these values fall below 50 ug/L.
3. The manganese NC Water Quality Standard as defined for WS class waters is currently under review.
Compliance with this limit shall commence 48 months from the permit effective date.
4. Parameters shall be monitored in conjunction with toxicity test.
5. 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.
6. Chronic Toxicity (Ceriodaphnia dubia) Monitoring at 21%; February, May, August, and November.
See special condition A. (2).
b. All samples collected should be from a representative discharge event.
c. There shall be no discharge of floating solids or visible foam in other than trace amounts.
Page 3 of 6

Permit NCO028037
A. (2.) CHRONIC TOXICITY MONITORING (QRTRLY)
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 21 %. 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
TGP313. 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
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 6

Permit NCO028037
A. (3.) ELECTRONIC REPORTING OF DISCHARGE MONITORING REPORTS
Proposed federal regulations require electronic submittal of all discharge monitoring reports (DMRs)
and specify that, if a state does not establish a system to receive such submittals, then permittees must
submit DMRs electronically to the Environmental Protection Agency (EPA). The Division anticipates
that these regulations will be adopted and is beginning implementation in late 2013.
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 (Supersedes Section D. (2.) and Section E. (5.) (a)1
Beginning no later than 270 days from the effective date of this permit, the permittee shall begin
reporting discharge monitoring data electronically using the NC DWR's Electronic Discharge
Monitoring Report (eDMR) internet 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. Until such time that the state's
eDMR application is compliant with EPA's Cross -Media Electronic Reporting Regulation
(CROMERR), permittees will be required to submit all discharge monitoring data to the state
electronically using eDMR and will be required to complete the eDMR submission by printing,
signing, and submitting one signed original and a copy of the computer printed eDMR to the
following address:
NC DENR / Division of Water Resources / Water Quality Permitting Section
ATTENTION: Central Files
1617 Mail Service Center
Raleigh, North Carolina 27699-1617
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 mailing address above.
Requests for temporary waivers from the NPDES electronic reporting requirements 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 using eDMR. Temporary waivers shall be
valid for twelve (12) months and shall thereupon expire. At such time, DMRs shall be submitted
electronically to the Division unless the permittee re -applies for and is granted a new temporary
waiver by the Division.
Information on eDMR and application for a temporary waiver from the NPDES electronic
reporting requirements is found on the following web page:
http://portal.ncdenr.org/web/wq/admin/bog/ipu/edmr
Page 5 of 6

Permit NCO028037
(Continued A. (3.) ELECTRONIC REPORTING OF DISCHARGE MONITORING REPORTS)
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.
2. 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
Il, Section B. (I I.)(a) or by a duly authorized representative of that person as described in Part Il,
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://portal.ncdenr.org/web/wq/admin/bog/ipu/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:
7 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. "
3. Records Retention [Supplements Section D. WA
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 request of the Director at any time [40 CFR
122.41].
A. (4.) NUTIENT REOPENER FOR HIGH LAKE
This permit may be reopened and modified to implement nutrient requirements in accordance with any
future TMDL and/or nutrient management strategy for High Rock Lake.
Page 6 of 6

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