NC0024945_Draft Permit_20240122

ROY COOPER
Governor
ELIZABETH S. BISER
Secretary
RICHARD E. ROGERS, JR.
Director
Mr. Joseph Lockler
Operations Chief
Charlotte Water
5100 Brookshire Boulevard
Charlotte, North Carolina 28216
Dear Mr. Lockler:
NORTH CAROLINA
EnWroxi mmlQuality
January 23, 2024
Subject: Draft NPDES Permit Renewal
Permit NCO024945
Irwin Creek WRRF
Mecklenburg County
Grade IV Biological WPCS
SIC Code 4952
Enclosed with this letter is a copy of the Draft NPDES permit renewal for your facility. Please
review this draft carefully to ensure thorough understanding of the requirements and conditions it
contains. There are several changes from the existing permit, including the following:
The facility name has been revised to reflect the name change documentation received by
the Division on January 19, 2024.
• The facility components list has been updated to reflect changes made to the facility.
• The permit expiration month has been revised to reflect a 5-year cycle more closely.
• Based on the reasonable potential analysis (RPA) showing no reasonable potential to
violate state water quality standards, the monitoring requirements for total silver, total copper,
and total chromium, as well as the limits and monitoring requirements for total cyanide have
been removed from the permit [See A.(1)].
For calculation of total nitrogen and total phosphorous loadings, monitoring requirements
for total monthly flow, TKN and Nitrate + Nitrite have been added to the permit [See A.(1.)].
Total Phosphorous reporting requirements have been further broken down into total
phosphorous concentration, monthly loading and 12-month loading [See A.(1.)].
Language has been added to Special Condition A.(4.) Combined Limitation for Total
Phosphorous and A.(5.) Calculation and Reporting of Total Phosphorous Loads to further
clarify the requirements.
The statement, "There shall be no discharge of floating solids or visible foam in other than
trace amounts," has been added back into the permit [See A.(1.)].
• Total Residual Chlorine (TRC) limits and monitoring requirement have not been in the
permit, as the facility uses UV for disinfection. However, in the event of an emergency where
chlorination is required as a backup or temporary means of disinfection at the facility, a TRC
limit and monitoring requirement have been added to the permit. Please note that TRC
monitoring is only required when chlorine is used at the facility, and as part of the regular
Effluent Pollutant Scans.
D_E Q North Carolina Department of Environmental Quality I Division of Water Resources
512 North Salisbury Street 1 1611 Mail Service Center I Raleigh, North Carolina 27699-1611
�\ �/ 919.707.9000

To assess the industrial contribution of HAS to the Irwin Creek WRRF and assess levels
of PFAS compounds in the facility effluent, Special Condition A.(7.) has been added to the
permit. Please review each paragraph carefully.
• As the facility receives complex waste streams from various industrial users with the
potential to discharge 1,4-dioxane via their pretreatment program, monthly monitoring for
1,4-dioxane as well as a 1,4-dioxane reopener condition have been added to the permit. After
a 24-month sampling period, the Permittee may request the Division conduct a review of
submitted data for assessment and approval of a 1,4-dioxane monitoring frequency reduction
from monthly to quarterly [See A.(l.) and Special Condition A.(8.)].
• Some of the wording has changed in Special Condition A.(3.), Chronic Toxicity Permit
Limit, please review each paragraph carefully.
• Special Condition A.(6.) has been modified to include the specific three years in which the
Effluent Pollutant Scan shall be performed (2025, 2026, and 2027). In addition, at the end of
the Special Condition, 2°d species Toxicity Testing Requirements for municipal permit
renewals per Federal Regulations [40 CFR 122.210)(5)] have been added.
A notation was made concerning the Electronic Reporting Rule — NPDES Electronic
Reporting Rule — Phase 2 Extension. EPA extended the Phase 2 deadline to December 21,
2025.
Federal regulations require electronic submittal of all discharge monitoring reports
(DMRs) and program reports. The requirement to continue reporting discharge monitoring data
electronically using the NC DWR's Electronic Discharge Monitoring Report (eDMR) internet
application has been added to your NPDES permit [See Special Condition A.(10.)].
Please note that the Division considers "Between 6.0 and 9.0 standard units" for pH permit
limitations to mean greater than or equal to 6.0 standard units and less than or equal to 9.0 standard
units for compliance purposes.
Please note that on 9/12/2023 the Municipal Unit received correspondence from EPA' s Office of
Information Management (The EPA CROMERR Team) confirming CROMERR compliance for
the Charlotte Water SwiftComply system. The Division reviewed and approved the complete
application submitted by Charlotte Water on 11/l/2023.
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 except that agency and division names have been updated. The latest version is available at
https://bit.ly/3k5NFaL and can be viewed online or downloaded as a PDF file.
Concurrent with this notification the Division is publishing a notice in a newspaper having
circulation in the general Mecklenburg County area, soliciting public comments on this draft
permit. Please provide any written comments you may have to the following: NCDEQ/DWR,
NPDES Permitting Branch, 1617 Mail Service Center, Raleigh, NC 27699-1617 no later than 30
days after receipt of this draft permit.
D_E Q North Carolina Department of Environmental Quality I Division of Water Resources
4g;512 North Salisbury Street 1 1611 Mail Service Center I Raleigh, North Carolina 27699-1611
o.rr
919.707.9000

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 this
draft permit, please call me at [phone] or by email at [e-mail].
Sincerely,
Nick Coco, PE
NPDES Municipal Permitting Unit
Hardcopy: NPDES Files
Ecopy: US EPA Region 4
DWR/Mooresville Regional Office/Water Quality/Andrew Pitner & Wes Bell
DWR/Operator Certification Program/JeffTalbot
DWR/Aquatic Toxicology Branch/Cindy Moore & Molly Nicholson
DWR/Municipal Permitting Unit/Keyes McGee
SCDHECBrenda Green & Wade Cantrell
North Carolina Department of Environmental Quality I Division of Water Resources
512 North Salisbury Street 1 1611 Mail Service Center I Raleigh, North Carolina 27699-1611
o�c,.UMmme��,�ida,i\ r 919.707.9000

Permit NCO024945
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 provisions 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,
Charlotte Water
is hereby authorized to discharge wastewater from a facility located at the
Irwin Creek Water Resource Recovery Facility (WRRF)
4000 Westmont Drive
Charlotte
Mecklenburg County
to receiving waters designated as Irwin Creek in the Catawba 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............ May 1, 2024.
This permit and authorization to discharge shall expire at midnight on ......................................... October 31, 2028.
Signed this day .................. Month xx, 2024.
DRAFT
Michael J. Montebello, NPDES Permitting Branch Chief
Division of Water Resources

Permit NCO024945
SUPPLEMENT TO PERMIT COVER SHEET
Allprevious 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.
Charlotte Water
is hereby authorized to:
1. Continue to operate and maintain Irwin Creek WRRF, an existing 15.0 MGD facility consisting of the
following components:
• Mechanical bar screens
• Influent pump station
• Grit removal
• Flow Equalization .
• Primary clarifiers
• Alkalinity addition for nitrification
• Aeration basins
• Secondary clarifiers
• Tertiary filters
• Effluent flow meters
• UV disinfection
• Cascade aeration
• Anaerobic digesters
• Secondary digester tanks
• WAS sludge storage tank
• Gravity belt thickeners m
• Dewatering belt filter presses
• Digested sludge storage tank
• Backup generators
2. Discharge from said treatment works at the location specified on the attached map via Outfall 001 into Irwin
Creek, classified C waters in the Catawba River Basin and 03050103 RUC.
Page 2 of 15

Permit NCO024945
PART I
A.(1.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS [15.0 MGD]
[15A NCAC 02B .0400 et seq., 15A NCACO2B .0500 et seq.] Grade IV
Biological Water Pollution Control System [I 5A NCAC 08G .0302]
(a.) During the period beginning on the effective date of the permit and lasting until permit expiration, the
permittee is authorized to discharge treated municipal and industrial wastewater from Outfall 001. Such
discharges shall be limited and monitored' by the permittee as specified below:
EFFLUENT LIMITS
MONITORING REQUIREMENTS
PARAMETER
Parameter Code
Monthly
Weekly
Daily
Measurement
Samplc Type
Sample
Average
Average
Maximum
Frequency
Location
Flow 50050
15.0 MGD
Continuous
Recording
Influent or
Effluent
Total Monthly Flow (MG) 82220
Monitor and Report
Monthly
Recorded or
Influent or
Calculated
Effluent
CBOD5, (20°C) 2
80082
5.0 mg/L
7.5 mg/L
2/Week 3
Composite
Influent and
(April 1 -October 31)
Effluent
CBOD5, (20°C) 2 80082
10.0 mg/L
15.0
2/Week 3
Composite
Influent and
(November 1- March 31)de'
Effluent
Total Suspended Solids 2 C0530
30.0 mg/L
45.0 m
2/Week 3
Composite
Influent aEffluennd
NH3 as N
(April 1 -October 31) C0610
1.2
3.6 mg/L
2/Week '
Composite
Effluent
NH3 as N
C0610
2.3 mg/L
6.9 mg/L
2/Week '
Composite
Effluent
(November 1- March 31)
Dissolved Oxygen 00300
Daily Average > 6.0 mg/L
Daily
Grab
Effluent
Fecal Coliform
31616
200/100 1
400/100 1
1000/100
2/Week '
Grab
Effluent
(geometric mean)
mL
mL
pH 00400
Between 6.0 and 9.0 standard units
Daily
Grab
Effluent
Temperature (°C) 00010
Monitor and Report
Daily
Grab
Effluent
Conductivity (µmhos/cm) 00094
Monitor and Report
Daily
Grab
Effluent
Total Residual Chlorine 50060
17 µg/L
Daily
Grab
Effluent
Total Nitrogen (NO2+NO3+TKN) (mg/L) C0600
Monitor and Report
Monthly
Calculated
Effluent
TKN (mg/L) 00625
Monitor and Report
Monthly
Composite
Effluent
NO3-N + NO2-N (mg/L) 00630
Monitor and Report
Monthly
Composite
Effluent
Total Phosphorus (mg/L) C0665
Monitor and Report
Monthly
Composite
Effluent
Monthly TP Load (lb/mo) 5,6,7 QM665
See Conditions A.(4.) and A.(5.)
Monthly
Calculated
Effluent
12-Month TP Load (lb/yr)5,6,7 QY665
Monitor and Report
Monthly
Calculated
Effluent
Total Phenolic Compounds 32730
Monitor and Report
Quarterly
Grab
Effluent
(µg/L)
Chronic Toxicity 8 TGP3B
Monitor and Report
Quarterly
Composite
Effluent
Hardness -Total as CaCO3 (mg/L) 00900
Monitor and Report
Quarterly
Composite
Effluent
PFAS variable
Footnote 9
Footnote 9
Grab
Effluent
1,4-Dioxane10 82388
Monitor and Report
Monthly
Grab
Effluent
Effluent Pollutant Scan NCO]
Monitor and Report
Footnote I I
Footnote 11
Effluent
Footnotes:
1. The permittee shall submit Discharge Monitoring Reports electronically using NC DWR's eDMR application system.
See Special Condition A.(10.).
Footnotes continue on the next page.
Page 3 of 15

Permit NCO024945
2. The monthly average effluent CBOD5 and Total Suspended Solids concentrations shall not exceed 15% of the respective
influent value (85% removal).
3. Twice per week sampling must occur on any two non-consecutive days during the calendar week.
4. The facility shall monitor TRC when using chlorination for disinfection. The Division shall consider all effluent total
residual chlorine values reported below 50 µg/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 µg/l.
5. The requirements for Monthly TP Load (lb/mo, QM665) and 12-Month TP Load (lb/yr, QY665) apply to discharges
from this Irwin Creek WWTP. These parameters are defined in Condition A.(5.) of this permit.
6. The Permittee is also subject to a Combined TP Load limit (lb/day, RA665) on the combined discharges from the
McAlpine Creek, Sugar Creek, and Irwin Creek facilities in accordance with Conditions A.(4.) and A.(5.).
7. All TP Load values shall be calculated and reported as specified in this Condition and Conditions A.(4.) and A.(5.).
8. Chronic Toxicity (Ceriodaphnia dubia) P/F at 83% with testing in January, April, July, and October. See Special
Condition A.(3.).
9. See Special Condition A.(7.).
10. Samples will be analyzed and reported using sufficiently sensitive test procedures (i.e., methods) approved under 40
CFR part 136 for the analysis of pollutants or pollutant parameters. After a 24-month sampling period, the Permittee may
request the Division conduct a review of submitted data for assessment and approval of a 1,4-dioxane monitoring
frequency reduction from monthly to quarterly.
11. The permittee shall perform three effluent pollution scans during the term of this permit. See Special Condition A.(6.).
There shall be no discharge of floating solids or visible foam in other than trace amounts.
Page 4 of 15

Permit NCO024945
A.(2.) INSTREAM MONITORING REQUIREMENTS
[15A NCAC 02B.0500 et seq.]
Instream monitoring requirements for Irwin Creek WWTP's receiving streams, Irwin Creek and Sugar Creek,
shall be maintained in McAlpine Creek WWMF's permit (NC0024970). Instream monitoring and reporting
requirements for Irwin Creek and Sugar Creek will be identified in McAlpine Creek WWMF's permit
(NC0024970) and shall continue to be submitted on McAlpine Creek WWMF's electronic discharge monitoring
reports.
A.(3.) CHRONIC TOXICITY PERMIT LIMIT (QUARTERLY)
[15A NCAC 02B .0200] [15A NCAC 02B .0500 et seq]
The effluent discharge shall at no time exhibit observable inhibition of reproduction or significant mortality to
Ceriodaphnia dubia at an effluent concentration of 83%.
The permit holder shall perform at a minimum, quarterly monitoring using test procedures outlined in the "North
Carolina Ceriodaphnia Chronic Effluent Bioassay Procedure," (Revised December 2010, or subsequent versions)
or "North Carolina Phase II Chronic Whole Effluent Toxicity Test Procedure" (Revised December 2010, or
subsequent versions). The tests will be performed during the months of January, April, July and October.
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.
If the test procedure performed as the first test of any single quarter results in a failure or ChV below the
permit limit, then multiple -concentration testing shall be performed at a minimum, in each of the two
following months as described in "North Carolina Phase II Chronic Whole Effluent Toxicity Test
Procedure" (Revised -December 2010, or subsequent versions).
All toxicity testing results required as part of this permit condition will be entered electronically using the
Division's eDMR system for the months in which tests were performed, using the parameter code TGP3B for the
pass/fail results and THP3B for the Chronic Value. Additionally, DWR Form AT-3 (original) is to be sent to the
following address: 1 ems_.
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, accurate, include all supporting chemical/physical measurements and all
concentration/response data, and be certified by laboratory supervisor and ORC or approved designate signature.
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, monitoring will be
required during the following month. Assessment of toxicity compliance is based on the toxicity testing quarter,
which is the three-month time interval that begins on the first day of the month in which toxicity testing is
required by this permit and continues until the final day of the third month.
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.
Page 5 of 15

Permit NC0024945
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.(4.) COMBINED LIMITATION FOR TOTAL PHOSPHORUS
[NCGS 143-215.1 (b)]
(a.) As stipulated by the 2002 Settlement Agreement between Charlotte -Mecklenburg Utilities (now Charlotte
Water), the South Carolina Department of Health and Environmental Control (SC DHEC), and the North
Carolina Division of Water Quality (now the Division of Water Resources, NC DWR), Charlotte Water's
McAlpine Creek WWMF, Sugar Creek WWTP and Irwin Creek WWTP must comply with a combined
limit for Total Phosphorus.
(b.) Accordingly, during the period beginning on the effective date of this permit and lasting until expiration,
the Permittee continues to be authorized to discharge Total Phosphorus from the McAlpine Creek WWMF
(NC0024970, Outfall 001), the Sugar Creek WWTP (NC0024937, Outfalls 001 and 002), and the Irwin
Creek WWTP (NC0024945, Outfall 001) subject to a combined TP load limitation of 826.0 lb/day,
calculated as a rolling 12-month average daily load.
(c.) Monitoring requirements for Total Phosphorus shall be as specified in the Effluent Limitations and
Monitoring Requirements in each of the specified permits.
(d.) TP Loads shall be calculated and reported as specified in the Calculation and Reporting of Total
Phosphorus Loads condition in the facilities' individual NPDES permits. See Condition A.(5), below. The
Combined TP Load (Outfall TPO1) shall be reported on the DMRs for the McAlpine Creek WWMF.
A.(5.) CALCULATION AND REPORTING OF TOTAL PHOSPHORUS LOADS
[NCGS 143-215.1 (b)]
(a.) The Permittee shall calculate TP Loads for the Irwin Creek WWTP as follows and report the results in the
facility's discharge monitoring report (DMR) for Outfall 001:
(i.) Monthly TP Load (lb/mo, QM665) = TP x TMF x 8.34
where:
TP = the average of total phosphorus concentrations (mg/L) of the composite
samples collected during the month
TMF = the Total Monthly Flow of wastewater discharged during the month
(MG/mo); that is, the sum of daily flows in the month
8.34 = conversion factor, from (mg/L x MGD) to pounds
(ii.) 12-Month TP Load (lb/yr, QY665) = Sum of the Monthly TP Loads for the 12-month
period ending with the reporting month
(b.) The Permittee shall calculate the rolling 12-month average daily TP load (or Combined TP Load) for the
McAlpine Creek WWMF (Outfall 001), Sugar Creek WWTP (Outfalls 001 and 002), and Irwin Creek
WWTP (Outfall 001) and report the results as prescribed in the McAlpine Creek facility permit
NC0024970.
Page 6 of 15

Permit NC0024945
A.(6.) ADDITIONAL MONITORING REQUIREMENTS FOR PERMIT RENEWAL
[G.S. 143-215.1(B)]
(a.) Effluent Pollutant Scans. The permittee shall perform a total of three (3) Effluent Pollutant Scans for all
parameters listed below. One scan must be performed in each of the following years: 2025, 2026, and
2027. Analytical methods shall be in accordance with 40 CFR Part 136 and shall be sufficiently sensitive to
determine whether parameters are present in concentrations greater than applicable standards and criteria.
Each annual sample shall coincide with one quarterly toxicity test each year (see Condition A.(3.)
(CHRONIC TOXICITY PERMIT LIMIT (QUARTERLY))), and each must be collected in a different
calendar quarter to represent seasonal variation [i.e., do not sample in the same quarter every year]. Unless
otherwise indicated, metals shall be analyzed as "total recoverable."
Ammonia (as N)
C0610
Trans-1,2-dichloroethylene
34546
Bis (2-chloroethyl) ether
34273
Chlorine (total residual, TRC)
50060
1,1-dichloroethylene
34501
Bis (2-chloroisopropyl) ether
34283
Dissolved oxygen
00300
1,2-dichloropropane
CO541
Bis(2-ethylhexyl) phthalate
C0100
Nitrate / Nitrite
00630
1,3-dichloropropylene
77163
4-bromophenyl phenyl ether
34636
Kjeldahl nitrogen
00625
Ethylbenzene
34371
Butyl benzyl phthalate
34292
Oil and grease
00556
Methyl bromide
34413
2-chloronaphthalene
34581
Phosphorus
C0665
Methyl chloride
34418
4-chlorophenyl phenyl ether
34641
Total dissolved solids
70295
Methylene chloride
34423
Chrysene
34320
Hardness
00900
1,1,2,2-tetrachloroethane
81549
Di-n-butyl phthalate
39110
Antimony
01097
Tetrachloroethylene
34475
Di-n-octyl phthalate
34596
Arsenic
01002
Toluene
34010
Dibenzo(a h)anthracene
34556
Beryllium
01012
1, 1, 1 -trichloroethane
34506
1,2-dichlorobenzene
34536
Cadmium
01027
1,1,2-trichloroethane
34511
1,3-dichlorobenzene
34566
Chromium
C0034
Trichloroethylene
39180
1,4-dichlorobenzene
34571
Copper
01042
Vinyl chloride
39175
3,3-dichlorobenzidine
34631
Lead
01051
Add -extractable compounds:
Diethyl phthalate
34336
Mercury (Method 1631E)
COMER
P-chloro-m-cresol
34452
Dimethyl phthalate
34341
Nickel
01067
2-chlorophenol
34586
2,4-dinitrotoluene
34611
Selenium
01147
2,4-dichlorophenol
34601
2,6-dinitrotoluene
C0626
Silver
01077
2,4-dimethylphenol
34606
1,2-diphenylhydrazine
34346
Thallium
01059
4,6-dinitro-o-cresol
34657
Fluoranthene
C0376
Zinc
01092
2,4-dinitrophenol
34616
Fluorene
34381
Cyanide
00720
2-nitrophenol _
34591
Hexachlorobenzene
C0700
Total phenolic compounds
32730
4-nitrophenol
34646
Hexachlorobutadiene
C0702
Volatile oceanic compounds:
Pentachlorophenol
39032
Hexachlorocyclo-pentadiene
34386
Acrolein
34210
Phenol
34694
Hexachloroethane
34396
Acrylonitrile
34215
2,4,6-trichlorophenol
34621
Indeno(1,2,3-cd)pyrene
34403
Benzene
34030
Base -neutral compounds:
Isophorone
34408
Bromoform
32104
Acenaphthene
34205
Naphthalene
34696
Carbon tetrachloride
32102
Acenaphthylene
34200
Nitrobenzene
34447
Chlorobenzene
34301
Anthracene
CO220
N-nitrosodi-n-propylamine
34428
Chlorodibromomethane
34306
Benzidine
39120
N-nitrosodimethylamine
34438
Chloroethane
85811
Benzo(a)anthracene
C0526
N-nitrosodiphenylamine
34433
2-chloroethyl vinyl ether
34576
Benzo(a)pyrene
34247
Phenanthrene
34461
Chloroform
32106
3,4 benzofluoranthene
34230
Pyrene
34469
Dichlorobromomethane
32101
Benzo(ghi)perylene
34521
1,2,4-trichlorobenzene
C0551
1,1-dichloroethane
34496
Benzo(k)fluoranthene
34242
1,2-dichloroethane
32103
Bis (2-chloroethoxy) methane
34278
(b.) Effluent Scan Reporting. Test results shall be reported electronically via eDMR by December 31 st of
each designated sampling year, except that, subject to prior written approval by the Director, results can be
reported on DWR Form DMR-PPA-1 or other form approved by the Director. The permittee must at least
report completion of the test in the eDMR system by entering "1" or "Y" for parameter code NCO -
Page 7 of 15

Permit NCO024945
Annual Pollutant Scan. If written reports are approved, the report shall be submitted to the following
address:
North Carolina Division of Water Resources
Central Files
1617 Mail Service Center
Raleigh, North Carolina 27699-1617
Or the form may be uploaded at: https://edocs.deq.nc.gov/Forms/NPDES_WW-EDMR-Supplemental-Form
(c.) 2nd-Species Toxicity Testing and Reporting.
(i.) In addition to the quarterly toxicity tests required in Condition A.(3.) (CHRONIC TOXICITY
PERMIT LIMIT (QUARTERLY)), the Permittee shall perform and report the results of four (4)
toxicity tests using the same test methods using a second species of test organism suitable to the tests
being conducted.
(ii.) The 2nd species toxicity tests shall be conducted either:
(A) Once per quarter in a single 12-month period (four samples); if this option is chosen, the
sample for each 2nd species test shall coincide with the quarterly samples collected for
(CHRONIC TOXICITY PERMIT LIMIT (QUARTERLY9); or
(B) Once per 12-month period in the four -and one-half year period prior to the scheduled
application for permit renewal (four samples); if this option is chosen, three of the samples for
the 2nd species test shall coincide with those for the annual effluent scans and the coincident
quarterly toxicity test, and each of the four annual samples shall be collected in a different
calendar quarter in order to represent seasonal variation.
(iii.) The results of the toxicity tests shall be submitted to the following address:
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, [e-mail].
(iv.) Results of the 2nd species tests shall also be summarized in Part E (Toxicity Testing Data) of EPA
Municipal Application Form 2A when submitting the permit renewal application to the NPDES
Wastewater Program.
The Permittee may contact the Division's Aquatic Toxicology Branch at 919-743-8401 for guidance
on conducting the additional toxicity tests and reporting of the results.
A.(7.) PFAS MONITORING REQUIREMENT AND PRETREATMENT
[G.S. 143-215.1(b.)]
(a) In the absence of a final 40 CFR Part 136 method, influent and post -filtration PFAS monitoring shall be
conducted. The 3'd or more recent wastewater draft analytical method 1633 (see 40 CFR 122.2 1 (e)(3)(ii) and
40 CFR 122.44(i)(1)(iv)(B)) shall be used and shall include all target analytes listed under Table 1 of the draft
method until such time as the Permittee uses the Final PFAS Method for wastewater. Effective the first full
calendar quarter following six (6) months after EPA publishes a 40 CFR part 136 Final PFAS Method for
wastewater in the Federal Register, effluent PFAS monitoring shall be conducted using the approved EPA
Final PFAS Method 1633.
(b) Influent and post -filtration monitoring takes effect the first full calendar quarter following six (6) months
after the effective date of the permit (Month xx, 2024) and will be at a quarterly frequency thereafter.
(i.) Appendix A has been added to the permit to identify the current analytes listed under Table I of the 0'
Draft Method 1633 Analysis of Per- and Polyfluoroalkyl Substances (PFAS) July 2023, in Aqueous
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Permit NC0024945
Samples and the appropriate ICIS codes for use when reporting in the electronic Discharge Monitoring
Reports (eDMRs). The method and list of analytes may also be found at:
https://www.epa. go`ystem/files/documents/2022-
12/3rd%20Draft%20Method%201633%20December%202022%2012-20-22 508.pdf
PFAS Monitoring using the Draft Method 1633 shall be reported quarterly using the Division -provided
submittal form. Once PFAS monitoring is conducted using the EPA Final PFAS Method 1633, data shall
be reported in the monthly eDMRs.
(ii.) Please note that specific considerations and protocols are required to avoid cross -contamination and
minimize sample bias for PFAS. A current listing of laboratories accredited by the Perry Johnson
Laboratory Accreditation, Inc. (PJLA), ANSI National Accreditation Board (ANAB), or the American
Association for Laboratory Accreditation (A2LA) to perform EPA Draft Method 1633 can be found by
contacting the individual associations. Please note that different labs are accredited for different
matrices.
NOTES - Sampling and Analytical:
• Sampling shall be planned so that required holding times for analytical methods are met.
• Using one of the analytical laboratories included above will allow consistency in analytical method and
in anticipation of a final method.
• "J" flag values shall be reported when the "J" flag value is associated with the method's upper bound. "J"
flag values need not be reported when less than the method's Minimum Reporting Level (listed in Method
1633).
• Laboratories approved for Aqueous matrix may be utilized. Please note that the lab used does not have
to be in North Carolina.
(c) Pretreatment program activities:
(i.) PFAS Monitoring Applicability: Industry categories known or suspected to discharge PFAS from the
EPA PFAS Strategic Roadmap include: organic chemicals, plastics & synthetic fibers (OCPSF); metal
finishing; electroplating; electric and electronic components; landfills; pulp, paper & paperboard;
leather tanning & finishing; plastics molding & forming; textile mills; paint formulating, and airports.
This is not an exhaustive list and additional industries may also discharge PFAS. For example,
Centralized Waste Treatment (CWT) facilities may receive wastes from the aforementioned industries
and should be considered for monitoring. There may also be categories of dischargers that do not meet
the applicability criteria of any existing Effluent Limitation Guidelines (ELG); for instance,
remediation sites, chemical manufacturing not covered by OCPSF, and military bases. l'
'ELG categories of airport deicing, landfills, textile mills, and plastics molding and forming do not have
categorical pretreatment standards, and therefore small -volume indirect dischargers in those categories would
not ordinarily be considered Significant Industrial Users (SIUs) and may not be captured on an existing IU
inventory. IUs under the Paint Formulating category are only subject to Pretreatment Standards for New
Sources (PSNS), and existing sources may need to be inventoried.
(ii.) The Permittee shall identify and locate each Significant Industrial User (SIU) in the approved
pretreatment program in industry categories expected or suspected of PFAS discharges to the Irwin
Creek WWTP; and begin sampling of and modify Industrial User Permits (IUPs) for each SIU
identified as suspected of PFAS discharges to the Irwin Creek WWTP to ensure sampling begins within
six months of the permit effective date, by Month xx, 2024.
(iii.) Update Industrial Waste Survey (IWS) Inventory: POTWs must identify and locate all possible indirect
dischargers that might be subject to the pretreatment program and identify the character and volume of
pollutants contributed to the POTW by the indirect dischargers (see 40 CFR 403.8(f)(2)). As EPA
regulations require, this information shall be provided to the Division (see 40 CFR 122.440) and 40
CFR 403.8(f)(6)) as part of the 2024 Pretreatment Annual Report (PAR). The IWS inventory shall
be revised, as necessary, to include all indirect dischargers in industry categories expected or suspected
of PFAS discharges.'- (see 15A NCAC 02H .0906(b)(2)).
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Permit NCO024945
(iv.) The Permittee shall begin sampling of and/or issue IUPs for each indirect discharger identified as
suspected of PFAS discharges to the Irwin Creek WWTP to ensure sampling begins within six months
of completion of the IWS.
(v.) The Division has determined that all SIUs and indirect dischargers identified above analyze their
discharge for PFAS at the same quarterly sampling frequency and with the same analytical
method to ensure protection of human health and the environment due to the potential health hazards
associated with PFAS. Collection and evaluation of this information will also assist the Department in
developing sound policies with respect to PFAS in the environment.
(vi.) The Permittee shall ensure that IUPs within the Irwin Creek WWTP service area are modified or
reissued, new IUPs are issued, and other Pretreatment Program mechanisms are completed to address
PFAS discharges to POTWs.
(vii.) In the absence of local limits, and based upon data as they become available, POTWs shall encourage
Best Management Practices (BMPs), pollution prevention, product substitution, and good
housekeeping practices to make meaningful reductions in PFAS introduced to POTWs. Such BMPs
could be like those included in the EPA Office of Water, December 5, 2022, "Addressing PFAS
Discharges in NPDES Permits and Through the Pretreatment Program and Monitoring Programs."A3.
"Best Management Practices (BMPs) for discharges of PFAS, including product substitution,
reduction, or elimination of PFAS, as detected by draft method 1633".
(viii.) A summary of all actions taken by the Permittee and their industries and monitoring conducted by each
indirect discharger identified as part of this Special Condition shall be provided as part of the PAR (see
15A NCAC 02H .0908(b)).
4t
A.(8.) 1,4-DIOXANE RE -OPENER
[NCGS 143-215.1 (b)]
Pursuant to N.C. General Statutes Section 143-215.1 and the implementing rules found in the North Carolina
Administrative Code at 15A NCAC 2H.0112 (b) (1) and 2H.0114 (a) and Part II, Sections B-12 and B-13 of this
permit, the Director of DWR may reopen this permit to modify permit requirements to address 1,4-Dioxane
monitoring, treatment and/or compliance.
A.(9.) MERCURY MINIMIZATION PLAN (MMP)
[N.C.G.S. 143-215.1 (B)]
The Permittee shall maintain and continue to implement the Mercury Minimization Plan (MMP) developed in the
previous permit term. The MMP shall continue to be available for inspection on -site. The MMP should place
emphasis on identification of mercury contributors and goals for reduction. Results shall be summarized and
submitted with the next permit renewal. Performance of the MMP will meet the requirements of the TMDL (Total
Maximum Daily Load) for mercury approved by USEPA on October 12, 2012, unless and until a Waste Load
Allocation specific to this facility is developed and this NPDES permit is amended to require further actions to
address the Waste Load Allocation.
A.(10.) ELECTRONIC REPORTING - 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 Il 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
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Permit NC0024945
1. Reporting Requirements [Supersedes Section D. (2.) and Section E. (5.) (a)1
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
monthly 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
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; and
• 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
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Permit NC0024945
Electronic submissions must start by the dates listed in the "Reporting Requirements" section above.
3. How to Reauest a Waiver from Electronic Reportine
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 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://deg.nc.gov/about/divisions/water-resources/edmr
4. Signatory Requirements [Supplements Section B. (11.) (b) and Supersedes Section B. (11.) (d)l
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. (I1.)(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. 1 am aware that there are significant penalties for
submitting false information, including the possibility offines and imprisonment for knowing violations. "
5. Records Retention [Supplements Section D. (6.)]
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 122.411.
Page 12 of 15

Permit NCO024945
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NPDES Permit NCO02494S
Stream Segment: 11-137-1 Stream Class: C
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County: Mecklenburg HUC: 0305010301
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Page 13 of 15

Permit NCO024945
Appendix A. PFAS Target Analytes EPA Method 1633
41h Draft, July 2023).
Target Analyte Name
Abbreviation
CAS Number
Parameter
Code
Perfluoroalkyl carboxylic acids
Perfluorobutanoic acid
PFBA
375-22-4
51522
Perfluoropentanoic acid
PFPeA
2706-90-3
51623
Perfluorohexanoic acid
PFHxA
307-24-4
51624
Perfluoroheptanoic acid
PFHpA
375-85-9
51625
Perfluorooctanoic acid
PFOA
335-67-1
51521
Perfluorononanoic acid
PFNA
375-95-1
51626
Perfluorodecanoic acid
PFDA
335-76-2
51627
Perfluoroundecanoic acid
PFUnA
2058-94-8
51628
Perfluorododecanoic acid
PFDoA
307-55-1
51629
Perfluorotridecanoic acid
PFTrDA
72629-94-8
51630
Perfluorotetradecanoic acid
PFTeDA
376-06-7
51531
Perfluoroalkyl sulfonic acids
Perfluorobutanesulfonic acid
PFBS
375-73-5
52602
Perfluoropentanesulfonic acid
PFPeS
2706-91-4
52610
Perfluorohexanesulfonic acid
PFHxS
355-46-4
52605
Perfluoroheptanesulfonic acid
PFHpS
375-92-8
52604
Perfluorooctanesulfonic acid
PFOS
1763-23-1
52606
Perfluorononanesulfonic acid
PFNS
68259-12-1
52611
Perfluorodecanesulfonic acid
PFDS
335-77-3
52603
Perfluorododecanesulfonic acid
PFDoS
79780-39-5
52632
Fluorotelomer sulfonic acids
1H,1H,2H,2H-Perfluorohexane sulfonic acid
4:2FTS
757124-72-4
52607
1H,1H,2H,2H-Perfluorooctane sulfonic acid
6:2FTS
27619-97-2
52608
IH,IH,2H,2H-Perfluorodecane sulfonic acid
8:2FTS
39108-34-4
52609
Perfluorooctane sull'onamides
Perfluorooctanesulfonamide
PFOSA
754-91-6
51525
N-methyl perfluorooctanesulfonamide
NMeFOSA
31506-32-8
52641
N-ethyl perfluorooctanesulfonamide
NEtFOSA
4151-50-2
52642
Table continues on next page.
Table continued from Appendix A. PFAS Target Analytes EPA Method 1633 (4`h Draft, July 2023).
Page 14 of 15

Permit NCO024945
Target Analyte Name
Abbreviation
CAS Number
Parameter
Code
Perfluorooctane sulfonamidoacetic acids
N-methyl perfluorooetanesulfonamidoacetic acid
NMeFOSAA
2355-31-9
51644
N-ethyl perfluorooctanesulfonamidoacetic acid
NEtFOSAA
2991-50-6
51643
Perfluorooctane sulfonamide ethanols
N-methyl perfluorooctanesulfonamidoethanol
NMeFOSE
24448-09-7
51642
N-ethyl perfluorooctanesulfonamidoethanol
NetFOSE
1691-99-2
51647
Per- and Polyfluorother carboxylic acids
Hexafluoropropylene oxide dimer acid
HFPO-DA
13252-13-6
52612
4,8-Dioxa-3H-perfluorononanoic acid
ADONA
919005-14-4
52636
Perfluoro-3-methoxypropanoic acid
PFMPA
377-73-1
PF002
Perluoro-4-methoxybutanoic acid
PFMBA
863090-89-5
PF006
Nonafluoro-3,6-dioxaheptanoic acid
NFDHA
151772-58-6
52626
Ether sulfonic acids
9-Chlorohexadecafluoro-3-oxanonane- I -sulfonic acid
9C1-PF3ONS
756426-58-1
PF003
11-Chloroeicosafluoro-3-oxaundecane-l-sulfonic acid
11C1-PF3OUdS
763051-92-9
PF004
Perfluoro(2-ethoxyethane)sulfonic acid
PFEESA
113507-82-7
52629
Fluorotelemer carboxylic acids
3-Perfluoropropyl propanoic acid
3:3FTCA
356-02-5
PF001
2H,2H,3H,3H-Perfluorooctanoic acid
5:3FTCA
914637-49-3
PF007
3-Perfluoroheptyl propanoic acid
7:3FTCA
812-704
PF005
Page 15 of 15