NC0081426_Draft Permit_20220906

ROY COOPER . =c
Governor \rwAti
ELIZABETH S.BISER
Secretary
RICHARD E.ROGERS,JR. NORTH CAROLINA
Director Environmental Quality
September 09,2022
Mr.Michael Borchers
City of Greensboro
PO Box 3136
Greensboro,NC, 27402-3136
Subject: DRAFT NPDES PERMIT NC0081426
N.L. Mitchell WTP
Grade I PC WPCS
[15A NCAC 08G .0306]
Guilford County
Dear Mr. Borchers
In October of 2021,the Division noticed a draft NPDES permit for your facility. This draft included a
proposed addition of monthly monitoring for 1,4 Dioxane. After this notice process the Division has
worked to update its strategy for addressing 1,4 Dioxane. The updated strategy will not require
monitoring of 1,4 Dioxane for Water Treatment Plants, it instead focuses on areas that are more likely
potential sources of this pollutant. With this change, the Division is also moving to update your draft
permit to remove the proposed 1,4 Dioxane monitoring and re-notice your permit . All other change
proposed in the previous draft remain in place. Enclosed with this letter is a copy of the new draft permit
for your facility. Please review the draft very carefully to ensure thorough understanding of the conditions
and requirements it contains.
This draft contains the following changes from the existing permit:
• The facility's classification has been added above the effluent table.
• Iron monitoring requirements have been removed from the permit.There are no
longer action level standards for this parameter.
• Section A. (2)has been updated to include language for electronic submittal of
toxicity results
• The language of Section A.(4)Electronic Reporting of Monitoring Reports has
been updated to be consistent with current federal requirements for electronic
reporting.
• The monitoring frequency for copper has been corrected to monthly.Metals that
have been demonstrated as having reasonable potential for discharge require
limits and monthly monitoring.
This draft contains the following changes from the previous draft:
• Aluminum monitoring requirements have been removed in accordance with a comment
received on the draft permit. This facility does not use alum anywhere in its process.
• 1,4-Dioxane monitoring requirements have ben removed.
Please note that the receiving stream is listed as an impaired waterbody on the North Carolina 303(d)
Impaired Waters List. Addressing impaired waters is a high priority with the Division,and instream data
will continue to be evaluated. If there is noncompliance with permitted effluent limits and stream
impairment can be attributed to your facility, then mitigative measures may be required.
D E ..?-0). N512 orthNo Carthrolina DepartmentStreet o1 f Env
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The NPDES standard conditions (Parts II, III, and IV)that are a part of the permit are not included in this
draft document (cover, map,and Part I). The conditions are the same as in your current permit. The latest
version is available at https://bit.ly/2BZ4xxx and can be viewed online or downloaded as a PDF file.
With this notification, the Division will solicit public comment on this draft permit by publishing a notice
in newspapers having circulation in the general Guilford County area,per EPA requirements. Please
provide your comments, if any,to me 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,please
contact me via email at [[e-mail]].
Sincerely,
Emily Richards
Environmental Specialist II
NPDES Permitting Program
ec:NPDES files
Winston Salem Regional Office
DWR Public Water Supply—Eric Hudson Aquatic Toxicity Branch
D—� North Caroepartmnt of Environmental Quality I Division of Water Resources
512 Notth SalinalisbDury Street
e 11611 Mail Service Center I Raleigh,North Carolina 27699-1611
oiiuvm.ew �\ �/ 919.707.9000

Permit NC0081426
STATE OF NORTH CAROLINA
DEPARTMENT OF ENVIRONMENTAL QUALITY
DIVISION OF WATER RESOURCES
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, the
City of Greensboro
is hereby authorized to discharge wastewater from a facility located at the
N.L. Mitchell WTP
1041 Battleground Avenue
Greensboro
Guilford County
to receiving waters designated as North Buffalo Creek in subbasin 03-06-02 of the Cape Fear River Basin in
accordance with effluent limitations, monitoring requirements, and other conditions set forth in Parts I, II, III and
IV hereof.
This permit shall become effective.
This permit and authorization to discharge shall expire at midnight on June 30,2021.
Signed this day.
DRAFT
Richard E.Rogers,Jr,Director
Division of Water Resources
By Authority of the Environmental Management Commission
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Permit NC0081426
SUPPLEMENT TO PERMIT COVER SHEET
All previous NPDES Permits issued to this facility,whether for operation or discharge are hereby revoked,and as
of this 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 Greensboro
is hereby authorized to:
1. Continue to operate a conventional water treatment plant with a discharge of filter backwash
wastewaters. This water treatment plant facility currently has a design potable flowrate of 24 MGD
and a current maximum, monthly average wastewater discharge of 0 MGD. The facility is located at
the N.L. Mitchell WTP at 1041 Battleground Avenue, in Greensboro, in Guilford County.
2. Discharge from said treatment works via Outfall 001,at the location specified on the attached map
into North Buffalo Creek [stream ID: 16-11-14-1] currently classified WS-V;NSW waters in
subbasin 03-06-02 [HUC: 0303000201] of the Cape Fear River Basin.
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Permit NC0081426
Part I
A. (1) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS
[15A NCAC 02B.0400 et seq., 15A NCAC 02B.0500 et seq.]
Grade 1 Physical Chemical Water Pollution Control System [15A NCAC 08G .0306]
Beginning with the effective date of this permit and lasting until expiration,the Permittee is authorized to discharge
treated wastewater from Outfall 001. Such discharges shall be limited and monitored` by the Permittee as specified
below:
EFFLUENT MONITORING REQUIREMENTS
EFFLUENT CHARACTERISTICS LIMITATIONS
Parameter Code Monthly Daily Measurement Sample Sample
Average Maximum Frequency Type Location
Flow 50050 Monitor&Report Continuous Recording Effluent
Total Suspended Solids C0530 30.0 mg/L 45.0 mg/L 2/Month Grab Effluent
pH 00400 >6.0 and<9.0 standard units 2/Month Grab Effluent
Total Residual Chlorine 2 50060 17 pg/L 2/Month Grab Effluent
Turbidity 00070 Monitor&Report 2/Month Grab Effluent
Total Copper 01042 16.72 pg/L 22.90 pg/L Monthly Grab Effluent
Fluoride 4 00951 Monitor&Report Quarterly Grab Effluent
Total Zinc 5 01092 Monitor&Report Quarterly Grab Effluent
Hardness—Total as[as CaCO3 or 00900 Monitor&Report Quarterly Grab Effluent
(Ca+Mg)]6(mg/l)
Hardness—Total as[as CaCO3 or 00900 Monitor&Report Quarterly Grab Upstream
(Ca+Mg)](mg/I)
Ammonia Nitrogen 7 C0610 Monitor&Report Quarterly Grab Effluent
Total Nitrogen C0600 Monitor&Report Quarterly Grab Effluent
Total Phosphorus C0665 Monitor&Report Quarterly Grab Effluent
Whole Effluent Toxicity Monitoring TGP3B Monitor&Report Quarterly Grab Effluent
8
Footnotes:
1. The permittee shall submit discharge monitoring reports electronically using the NC DWR's eDMR system[see A.(4)].
2. The Division shall consider all effluent TRC values reported below 50 µg/I 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 µg/I.
3. EPA Method 624.1 is the required method for wastewater.After a minimum of 12 samples have been taken over a 12 month period,the
permittee may request the Division reevaluate the monitoring frequency for 1,4-dioxane.
4. Fluoride should be monitored if the Permittee backwashes with fluoridated finished water.
5. Zinc should be monitored if the Permittee adds zinc orthophosphate as a corrosion inhibitor prior to backwashing.
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Permit NC0081426
6. Effluent hardness sampling should be performed in conjunction with testing for hardness dependent metals(cadmium,copper,lead,
nickel,silver,and zinc).
7. Ammonia Nitrogen should be monitored if the Permittee uses chloramines (adds ammonia to chlorinated water) for secondary
disinfection prior to backwashing.
8. Ceriodaphnia dubia 7-day pass/fail test @ 90%concentration. See Condition A.(2.)for toxicity testing requirements.Toxicity testing
should be performed during the months of March,June,September and December.
THERE SHALL BE NO DISCHARGE OF FLOATING SOLIDS OR VISIBLE FOAM 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 90%. The testing shall be
performed as a Ceriodaphnia dubia 7-day pass/fail test. The tests will be performed during the months of March,
June, September and December. 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 electronically using the Divisions
eDMR system for the months in which tests were 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,NC 27699-1621
Or,results can be sent to the email,[e-mail].
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.
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Permit NC0081426
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.
A. (3) PERMIT RE-OPENER: WHOLE EFFLUENT TOXICITY
[NCGS 143-215.1(b)]
Whole Effluent Toxicity monitoring results indicating aquatic toxicity may result in the Division of Water
Resources re-opening this permit or requesting by letter that further action be taken. Additional metals
testing, a toxicity identification evaluation,a toxicity reduction evaluation,and/or an assessment of discharge
treatment alternatives may be requested.
A. (4) ELECTRONIC REPORTING OF MONITORING REPORTS
[NCGS 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.) Reporting
• Section D. (6.) Records Retention
• Section E.(5.) Monitoring Reports
1. Reporting Requirements [Supersedes Section D.(2.)and Section E.(5.)(a)l
The permittee shall report 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. The eDMR system may be
accessed at: https://deq.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
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Permit NC0081426
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).
2. 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: https://www.federalregister.gov/documents/2015/10/22/2015-
24954/national-pollutant-discharge-elimination-system-npdes-electronic-reporting rule
Electronic submissions must start by the dates listed in the "Reporting Requirements" section above.
3. How to Request 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
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Permit NC0081426
waivers are not transferrable. Only permittees 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://deq.nc.gov/about/divisions/water-resources/edmr
4. 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. (11.)(a) or by a duly authorized representative of that person as described in Part II,
Section B. (11.)(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://deq.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."
5. Records Retention [Supplements Section D. (6.11
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].
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Permit NC0081426
Page 8 of 9

Permit NC0081426
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NPDES Permit NC0081426 A, Faca,ty t_ocaton 411114 4111„.,�
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County.Guilford 1.24,000 USGS Quad:Greensborc
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