NC0024945_Fact Sheet_20240126

Fact Sheet
NPDES Permit No. NCO024945
Permit Writer/Email Contact: Nick Coco, [e-mail]
Date: January 2, 2024
Division/Branch: NC Division of Water Resources/NPDES Municipal Permitting
Fact Sheet Template: Version 09Jan2017
Permitting Action:
0 Renewal
❑ Renewal with Expansion
❑ New Discharge
❑ Modification (Fact Sheet should be tailored to mod request)
Note: A complete application should include the following:
• For New Dischargers, EPA Form 2A or 2D requirements, Engineering Alternatives Analysis, Fee
• For Existing Dischargers (POTW), EPA Form 2A, 3 effluent pollutant scans, 4 2nd species WET
tests.
• For Existing Dischargers (Non-POTW), EPA Form 2C with correct analytical requirements based
on industry category.
Complete applicable sections below. If not applicable, enter NA.
1. Basic Facility Information
Facility Information
Applicant/Facility Name:
Charlotte Water/Irwin Creek Water Resource Recovery Facility (WRRF)
Applicant Address:
5100 Brookshire Blvd., Charlotte, NC 28216
Facility Address:
4000 Westmont Drive, Charlotte, NC 28217
Permitted Flow:
15.0 MGD
Facility Type/Waste:
MAJOR Municipal; 85.7% domestic, 14.3% industrial*
Facility Class:
Grade IV Biological Water Pollution Control System
Treatment Units:
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, Dewatering belt filter presses, Digested sludge storage tank,
Backup generators
Pretreatment Program (Y/N)
Y, LTMP
County:
Mecklenburg
Region
Mooresville
*Based on permitted flows.
Briefly describe the proposed permitting action and facility background: Charlotte Water has applied for
an NPDES permit renewal at 15.0 MGD for the Irwin Creek WRRF. A name change form was received
by the Division on January 19, 2024 informing the Division of a change in facility name from Irwin
Creek Wastewater Treatment Plant (WWTP) to Irwin Creek Water Resource Recovery Facility (WRRF).
Page 1 of 16

This facility serves a population of approximately 111,000 residents, as well as 20 significant industrial
users (SIUs), including 9 categorical industrial users (CIUs), via an approved pretreatment program.
Treated domestic and industrial wastewater is discharged via Outfall 001 into Irwin Creek, a class C
waterbody in the Catawba River Basin. Outfall 001 is located approximately 11 miles upstream of the
North Carolina -South Carolina border.
As noted in the application, Charlotte Water has completed a number of maintenance and improvement
operations at the facility, including assessments of the filter pump station and sludge drying beds,
cleaning of the digested sludge tank and digester, and a variety of rehabilitation and improvement
projects. Charlotte Water currently has plans for improvements to the UV disinfection system with an
estimated construction completion in 2027.
Sludge disposal: Biosolids residuals are permitted, managed, and disposed under a contract with Synagro.
Land application and land filling are the means for ultimate use of the residuals. This is managed under
permit WQ0000057.
Pretreatment: The Irwin Creek WRRF is the primary pretreatment facility for Charlotte Water's
pretreatment program. On 12/09/2022 the NPDES Municipal Permitting Branch of the Division of Water
Resources received Charlotte Water' s notice of intent to modify the pretreatment program' s legal
authority and procedures to receive reports from Industrial Users electronically (CROMERR
Application). Charlotte Water currently receives wet ink signature pretreatment reports from Industrial
Users (IUs). On 9/12/2023 the Municipal Unit received an email from Shirley Miller of EPA' s Office of
Information Management (aka, The EPA CROMERR Team), titled "CONFIRMING CROMERR
COMPLIANCE: Status of Charlotte Water, SwiftComply Application." This email indicates "The
CROMERR program confirms that the Charlotte Water SwiftComply system is CROMERR
compliant," and "The means of official action on the program modification request is entirely at
the discretion of NCDEQ." The Division reviewed and approved the complete application submitted by
Charlotte Water on l l/1/2023. A courtesy announcement of this approval has been incorporated into the
cover letter to the permit.
2. Receiving Waterbody Information:
Receiving Waterbody Information
Outfalls/Receiving Stream(s):
Outfall 001 — Irwin Creek
Stream Segment:
11-137-1
Stream Classification:
C
Drainage Area (mi2):
31.0
Summer 7Q 10 (cfs)
4.9
Winter 7Q10 (cfs):
7.7
30Q2 (cfs):
9.9
Average Flow (cfs):
43
IWC (% effluent):
83%
2022 303(d) listed/parameter:
Yes; listed as exceeding criteria for benthos and fish community)
Subject to TMDL/parameter:
Yes- State wide Mercury TMDL implementation; Fecal coliform
TMDL for Irwin Creek (DM 1000/10 ml); SC DHEC ongoing
development on nutrient TMDL in the Catawba basing
Basin/ HUC:
Catawba River/ 0305010301
USGS Topo Quad:
G15NW
'Irwin Creek is also listed in the 2022 Integrated Report as exceeding criteria for both turbidity and fecal
coliform.
2Please see attached for the 2020 SCDHEC Lower Catawba River Basin — 2020 Nutrient Study.
Page 2 of 16

3. Effluent Data Summary
Effluent data for Outfall 001 is summarized below for the period of June 2019 through December 2023.
Table 1. Effluent Data Summary Outfall 001
Permit
Parameter
Units
Average
Max
Min
Limit
Influent Flow
MGD
11.2
19.3
5.7
Effluent Flow'
MGD
13.6
22.3
6.4
MA 15.0
CBOD summer
mg/l
2.0
3.5
2
WA 7.5
MA 5.0
CBOD winter
mg/1
2.0
4.3
2
WA 15.0
MA 10.0
WA 3.6
NH3N summer
mg/l
0.1
0.5
0.1
MA 1.2
WA 6.9
NH3N winter
mg/l
0.1
1.8
0.1
MA 2.3
WA 45.0
TSS
mg/l
2.6
5.6
2.5
MA 30.0
0 > pH <
6.9.0
PH
SU
7.1
7.7
6.3
(geometric)
(geomean)
WA 400
Fecal coliform
#/100 ml
6000
1
1.4
MA 200
DM 1000
DO
mg/l
8.8
10.2
7.9
DA >6.0
Monitor &
Conductivity
umhos/cm
517
685
311
Report
Monitor &
Temperature
° C
21.5
26.8
14.1
Report
Monitor &
TN
mg/1
19.4
38.89
9.7
Report
Monitor &
TP
mg/1
1.2
7.9
0.1
Report
TP Load
lbs/day
406
495.37
288.68
826.0
Monitor &
Total Copper
ug/1
2.8
7.6
< 2
Report
Monitor &
Total Silver
ug/1
< 1
< I
< 1
Report
Monitor &
Total Chromium
ug/1
< 5
< 5
< 5
Report
MA 6.1
Total Cyanide
ug/1
< 10
< 10
< 10
DM 25.9
Monitor &
Total Hardness
mg/l
123
170
98
Report
MA -Monthly Average, WA -Weekly Average, DM -Daily Maximum, DA=Daily Average
'Charlotte Water transitioned from influent flow measurement to effluent flow measurement in September 2022 to
better understand discharge into the receiving stream. Charlotte Water's service area is treated by the NC0024970
McAlpine Creek WWMF, NC0024937 Sugar Creek WRRF and NC0024945 Irwin Creek WRRF. Each facility is
Page 3 of 16

capable of diverting flow to the other. In addition, Charlotte Water has acquired a permit for a greenfield
NC0089630 Stowe Regional WRRF, which will have the same capability of flow acceptance and diversion.
2 annual rolling average of combined discharge of 3 WWTPs: Sugar Creek WRRF, Irwin Creek WRRF, and
McAlpine Creek WWMF
4. Instream Data Summary
Instream monitoring may be required in certain situations, for example: 1) to verify model predictions
when model results for instream DO are within 1 mg/1 of instream standard at full permitted flow; 2) to
verify model predictions for outfall diffuser; 3) to provide data for future TMDL; 4) based on other
instream concerns. Instream monitoring may be conducted by the Permittee, and there are also
Monitoring Coalitions established in several basins that conduct instream sampling for the Permittee (in
which case instream monitoring is waived in the permit as long as coalition membership is maintained).
If applicable, summarize any instream data and what instream monitoring will be proposed for this
permit action: The current permit requires instream monitoring for several locations: Irwin Creek,
McAlpine Creek, Sugar Creek, and Little Sugar Creek. All of these receiving streams are a part of the
facility and facility owner's (Charlotte Water) instream monitoring program for Sugar Creek WRRF,
Irwin Creek WRRF, and McAlpine WWMF.
Instream monitoring for all parameters for Irwin Creek WRRF's receiving streams, Irwin Creek and
Sugar Creek, will be maintained in McAlpine Creek WWMF's permit (NC0024970).
For the Irwin Creek WRRF renewal, instream data for stations with IDs of IC1, SC1, SC2, SC3, SC4,
SC5 were analyzed for the period of June 2018 through October 2022 [instream review conducted at one
time for McAlpine Creek WWMF NC0024970, Sugar Creek WRRF NC0024937 and Irwin Creek
NC0024945). The Irwin Creek station (IC1), upstream of Irwin Creek WRRF, monitors for dissolved
oxygen, temperature, conductivity, chromium, and copper. The Sugar Creek stations, all downstream of
Irwin Creek WRRF, monitor for dissolved oxygen, temperature, and conductivity at SC I, SC2, and SC3.
Station SC4 monitors for dissolved oxygen, temperature, conductivity, chromium, and copper. SC5,
located in South Carolina and used for the water quality model to develop nutrient TMDLs for the Lower
Catawba Reservoirs, monitors for dissolved oxygen, temperature, conductivity, pH, ammonia (NH3-N),
Nitrate plus Nitrite, Total Kjeldahl Nitrogen (TKN), total phosphorus, and orthophosphate (see Table 2
below).
Table 2. Instream Monitoring for Irwin Creek WRRF, Irwin Creek and Sugar Creek
Station ID
Location
Parameters Sampled
ICI
Upstream, Irwin Creek
DO, temperature, conductivity, total
chromium, total copper
SC1
Downstream, Sugar Creek
DO, temperature, conductivity
SC2
Downstream, Sugar Creek
DO, temperature, conductivity
SC3
Downstream, Sugar Creek
DO, temperature, conductivity
SC4
Downstream, Sugar Creek
DO, temperature, conductivity, total
chromium, total copper
SC5
Downstream, Sugar Creek in South
Carolina
DO, temperature, conductivity, pH, NH3-N,
Nitrate plus Nitrite, total Kjeldahl nitrogen,
total phosphorus, orthophosphate
In addition to the instream monitoring requirements in the permit, Charlotte Water conducted sampling at
the Irwin and Sugar Creek stations for multiple parameters that overlap with requirements at other
stations as well as for total zinc at locations IC I and SC4. The data has been summarized in Table 3
below.
Page 4 of 16

Table 3. Instream Monitoring Data Summary Irwin Creek WRRF
IC1
SC1
SC2
SC3
SC4
SC5
Parameter
Units
Average
Average
Average
Average
Average
Average
(Min -Max)
(Min -Max)
(Min -Max)
(Min -Max)
(Min -Max)
(Min -Max)
Temperature
° C
20.1
21.2
20.7
21.0
21.4
21.8
(5.5-25.8)
(6.9-26.1)
(6.7-25.7)
(6.2-26.3)
(6.3-28.2)
(7.8-27.6)
DO
mg/1
8.3
8.2
7.9
8.1
8.1
7.9
(5.7-12.1)
(5.8-11.7)
(5.9-11.5)
(6.2-11.9)
(6.7-12)
(5.8-11.4)
Conductivity
µmhos/cm
198
320
315
294
295
357
(107-471)
(166-494)
(154-470)
(122--448)
(109-438)
(120-528)
Total
µg/I
< 5
_
_
5.0
-
Chromium
(< 5-7.1)
Total
µg/I
2.3
3.6
-
Copper
(< 2-4.4)
(< 2-11)
Total Zinc
µg/I
10.8
-
-
-
13.5
-
(< 10-20)
(< 10-20)
pH
s.u.
7.1
7.2
7.2
7.3
7.3
7.2
(6.5-7.7)
(6.8-8)
(6.6-7.7)
(6.7-7.8)
(6.7-7.8)
(6.4-7.7)
NO2+NO3
mg/1
0.98
7.0
6.8
5.8
5.0
8.0
(< 0.5-1.3)
(2.4-12)
(2-11)
(2-11)
(1.8-11)
(1.2-19)
TKN
mg/1
0.33
0.55
0.51
0.5
0.5
0.7
(< 0.3-0.5)
(< 0.3-1.6)
(< 0.3-1.2)
(< 0.3-1.1)
(< 0.3-0.8)
(< 0.2-2.2)
Ammonia
mg/1
-
-
-
-
-
0.1
(< 0.1-1.9)
TP
mg/l
< 0.1
0.5
0.5
0.4
0.3
0.3
(< 0.1-1.6)
(< 0.1-1.6)
(< 0.1-1.7)
(< 0.1-0.9)
(0.11-0.98)
Ortho-
mg/1
< 0.05
0.5
0.5
0.4
0.2
0.2
phosphate
(< 0.05-1.5)
(< 0.05-1.6)
(< 0.05-1.7)
(< 0.05-0.88)
(< 0.05-0.83)
Fecal
Geomean
Coliform
#/100ml
-
-
-
-
505
-
(46-75000)
Total
m /I
g
78.8
_
_
_
93
99
hardness
(53-110)
(52-120)
(49-150)
Students t-tests were run at a 95% confidence interval to analyze relationships between upstream
(IC1) and immediate downstream (SC1) samples. A statistically significant difference is determined
when the t-test p-value result is < 0.05. ANOVA tests were run at a 95% confidence interval to
analyze relationships among downstream (Sugar Creek) samples.
Downstream temperature was not greater than 29 degrees Celsius [per 15A NCAC 02B .0211 (18)] at any
instream monitoring location during the period reviewed. Downstream temperature was greater than
upstream temperature by more than 2.8 degrees Celsius on 7 occasions during the period reviewed.
Review of concurrent effluent temperature for these 7 occasions demonstrated a consistent relationship
between elevated effluent temperatures and elevated downstream temperature. Effluent temperature does
appear to have the potential to influence instream temperature. However, it was concluded that no
statistically significant difference exists between upstream (ICI) and downstream (SC1) temperature.
Additionally, it was concluded that no statistically significant difference exists for temperature among the
downstream sample locations (SC1-5).
Downstream DO did not drop below 5 mg/L [per 15A NCAC 02B .0211 (6)] during the period reviewed.
It was concluded that no statistically significant difference exists between upstream (IC 1) and
Page 5 of 16

downstream (SC1) DO. Additionally, it was concluded that no statistically significant difference exists for
DO among the downstream sample locations (SC 1-5).
Instream pH was between 6.0 and 9.0 standard units [per 15A NCAC 02B .0211 (14)] at all monitoring
locations during the period reviewed.
It was concluded that a statistically significant difference exists between upstream and downstream
conductivity, TKN, NO2+NO3, TP and Orthophosphate.
It was concluded that a statistically significant difference exists between upstream (IC1) and downstream
(SC4) copper. Downstream copper was generally observed at higher levels than upstream copper.
Effluent total copper was not generally monitored concurrently with instream total copper and an analysis
between effluent and instream total copper could not be made. However, both upstream and downstream
total copper were not observed at levels greater than the standard of 2 1. 0 ug/L (calculated based on
average reported upstream hardness of 78.8 mg/L and EPA Default Partition Coefficient of 0.348) during
the period reviewed.
Downstream (SC4) fecal coliform was observed at levels greater than 400/100mL in 43% of the samples
reported during the period reviewed. Concurrent effluent fecal coliform was reported consistently at
levels lower than downstream fecal coliform. To better understand any potential influence on downstream
fecal coliform, fecal coliform sampling closer to the facility's discharge is appropriate. The addition of
upstream fecal coliform monitoring at location IC 1 and downstream fecal coliform monitoring at location
SC has been proposed.
Based on the 2022 Integrated Report identifying turbidity as exceeding criteria in the receiving stream,
monitoring for turbidity upstream at location IC 1 and downstream at location SC 1 has been proposed.
No changes are proposed to the other Irwin and Sugar Creek instream monitoring requirements. All
instream monitoring for parameters for Irwin Creek WRRF's receiving streams, Irwin Creek and Sugar
Creek, and Sugar Creek WRRF's receiving stream, Little Sugar Creek, will be maintained in McAlpine
Creek WWMF's permit (NC0024970) along with McAlpine Creek instream monitoring requirements.
Please note that instream summaries will be provided for McAlpine Creek and Little Sugar Creek in the
applicable permit reviews.
Is this facility a member of a Monitoring Coalition with waived instream monitoring (YIN): NO
Name of Monitoring Coalition: NA
5. Compliance Summary
Summarize the compliance record with permit effluent limits (past 5 years): The facility reported one
daily maximum fecal coliform exceedance in 2019.
Summarize the compliance record with aquatic toxicity test limits and any second species test results
(past 5 years): The facility passed 20 of 20 quarterly chronic toxicity tests, as well as all 4 second species
chronic toxicity tests from January 2019 to October 2023.
Summarize the results from the most recent compliance inspection: The last facility inspection conducted
in November 2022 reported that the facility was compliant. The last pretreatment inspection conducted in
February 2023 reported that the program was compliant.
Charlotte Water experienced a significant wet weather event Tuesday January 9, 2024 into Wednesday
January 10, 2024 as the City received between 34" of rain in a relatively short period of time. The
treatment plants are running well given the magnitude of this event. Collectively, CLTWater's plants had
Page 6 of 16

a peak flow of 495MGD coming into the influent. This is the second largest volume of peak influent flow
pumped since Hurricane Florence in September of 2018. The pumped influent flow was being treated in
the plants and put into EQ storage. Irwin Creek permitted at 15 MGD had a peak influent flow rate of 75
MGD. Mallard Creek permitted at 13.1 MGD had a peak influent flow rate of 33 MGD. McDowell Creek
permitted at 12 MGD had a peak influent flow rate of 20 MGD. McAlpine Creek permitted at 64 MGD
had a peak influent flow rate of 212 MGD. Sugar Creek permitted at 20 MGD had a peak influent flow
rate of 136MGD, this is a record peak influent flow rate for this facility. Due to the large volume of
influent flow, CLTWater has almost exhausted its storm EQ storage at the Sugar Creek, Irwin Creek, and
McAlpine Creek WRRF's. Sugar Creek has 40 MG of storage with 30 MG in storage. Irwin Creek has 30
MG of storage with 15 MG in storage. McAlpine Creek has 80 MG of storage with 60-65 MG in storage.
Because of a second anticipated rain event on Friday of this week, CLTWater is having to run and process
larger amounts of water through the plants than normal. This is to make room in the storm EQ basins so
that heavier flows that can't be treated immediately, can be stored. McAlpine Creek has been running at
full treatment capacity of 120MGD. Sugar Creek has been running at full treatment capacity of 40 MGD.
Irwin Creek has been running at full treatment capacity of 30 MGD.
The higher base rated flows in the plants are leading to blending of secondary clarifier effluent flow and
tertiary treated flow at Sugar Creek, Irwin Creek, and McAlpine Creek. All facilities are currently in
compliance with all permit limits.
6. Water Quality -Based Effluent Limitations (WQBELs)
Dilution and MixingZones
ones
In accordance with 15A NCAC 2B.0206, the following streamflows are used for dilution considerations
for development of WQBELs: 1Q10 streamflow (acute Aquatic Life); 7Q10 streamflow (chronic Aquatic
Life; non -carcinogen HH); 30Q2 streamflow (aesthetics); annual average flow (carcinogen, HH).
If applicable, describe any other dilution factors considered (e.g., based on CORMIX model results): NA
If applicable, describe any mixing zones established in accordance with 15A NCAC 2B.0204(b): NA
Oxygen -Consuming Waste Limitations
Limitations for oxygen -consuming waste (e.g., BOD) are generally based on water quality modeling to
ensure protection of the instream dissolved oxygen (DO) water quality standard. Secondary TBEL limits
(e.g., BOD= 30 mg/1 for Municipals) may be appropriate if deemed more stringent based on dilution and
model results.
Ifpermit limits are more stringent than TBELs, describe how limits were developed: The current permit
limitations for CBOD are based on a 1991 agreement with Charlotte Water to upgrade Sugar Creek
WRRF, Irwin Creek WRRF, and McAlpine Creek WWMF to meet more restrictive advanced tertiary
limits for CBOD, ammonia and TSS in order for Charlotte Water to expand their plants. This agreement
was based on the receiving stream having reached its assimilative capacity for some parameters at the
time. The limits took effect in 1995. No changes are proposed from the previous permit limits.
Ammonia and Total Residual Chlorine Limitations
Limitations for ammonia are based on protection of aquatic life utilizing an ammonia chronic criterion of
1.0 mg/1(summer) and 1.8 mg/1(winter). Acute ammonia limits are derived from chronic criteria,
utilizing a multiplication factor of 3 for Municipals and a multiplication factor of 5 for Non -Municipals.
Page 7 of 16

Limitations for Total Residual Chlorine (TRC) are based on the NC water quality standard for protection
of aquatic life (17 ug/1) and capped at 28 ug/l (acute impacts). Due to analytical issues, all TRC values
reported below 50 ug/l are considered compliant with their permit limit.
Describe any proposed changes to ammonia and/or TRC limits for this permit renewal: The permit does
not currently set limits or monitoring requirements for TRC due to the facility employing UV treatment
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 based on the review in the attached WLA spreadsheet. Please note that TRC monitoring is
only required in the event that chlorine is used at the plant and as part of the regular Effluent Pollutant
Scans.
The current limitations for ammonia are based on protection of aquatic life utilizing an ammonia chronic
criterion of 1.0 mg/l (summer) and 1.8 mg/l (winter). Acute ammonia limits are derived from chronic
criteria, utilizing a multiplication factor of 3 for Municipals and a multiplication factor of 5 for Non -
Municipals. The ammonia limits have been reviewed in the attached WLA for toxicity and have been
found to be protective. No changes are proposed.
Reasonable Potential Analysis (RPA) for Toxicants
If applicable, conduct RPA analysis and complete information below.
The need for toxicant limits is based upon a demonstration of reasonable potential to exceed water quality
standards, a statistical evaluation that is conducted during every permit renewal utilizing the most recent
effluent data for each outfall. The RPA is conducted in accordance with 40 CFR 122.44 (d) (i). The NC
RPA procedure utilizes the following: 1) 95% Confidence Level/95% Probability; 2) assumption of zero
background; 3) use of %2 detection limit for "less than" values; and 4) streamflows used for dilution
consideration based on 15A NCAC 2B.0206. Effective April 6, 2016, NC began implementation of
dissolved metals criteria in the RPA process in accordance with guidance titled NPDES Implementation of
Instream Dissolved Metals Standards, dated June 10, 2016.
A reasonable potential analysis was conducted on effluent toxicant data collected between June 2019 and
November 2023. Pollutants of concern included toxicants with positive detections and associated water
quality standards/criteria. Based on this analysis, the following permitting actions are proposed for this
permit:
• Effluent Limit with Monitoring. The following parameters will receive a water quality -based
effluent limit (WQBEL) since they demonstrated a reasonable potential to exceed applicable
water quality standards/criteria: None
• Monitoring Only. The following parameters will receive a monitor -only requirement since they
did not demonstrate reasonable potential to exceed applicable water quality standards/criteria,
but the maximum predicted concentration was >50% of the allowable concentration: Total
Phenolic Compounds
• No Limit or Monitoring: The following parameters will not receive a limit or monitoring, since
they did not demonstrate reasonable potential to exceed applicable water quality
standards/criteria and the maximum predicted concentration was <50% of the allowable
concentration: Total Arsenic, Total Cadmium, Total Chromium, Total Copper, Total Cyanide,
Total Lead, Total Molybdenum, Total Nickel, Total Selenium, Total Silver, Total Zinc
• POTW Effluent Pollutant Scan Review: Three effluent pollutant scans were evaluated for
additional pollutants of concern.
o The following parameter(s) will receive a water quality -based effluent limit (WQBEL)
with monitoring, since as part of a limited data set, two samples exceeded the allowable
discharge concentration: None
o The following parameter(s) will receive a monitor -only requirement, since as part of a
limited data set, one sample exceeded the allowable discharge concentration: None
Page 8 of 16

o The following parameters will not receive a limit or monitoring, since they did not
demonstrate reasonable potential to exceed applicable water quality standards/criteria and
the maximum predicted concentration was <50% of the allowable concentration: Total
Beryllium
If applicable, attach a spreadsheet of the RPA results as well as a copy of the Dissolved Metals
Implementation Fact Sheet for freshwater/saltwater to this Fact Sheet. Include a printout of the RPA
Dissolved to Total Metal Calculator sheet if this is a Municipality with a Pretreatment Program.
Toxicity Testing Limitations
Permit limits and monitoring requirements for Whole Effluent Toxicity (WET) have been established in
accordance with Division guidance (per WET Memo, 8/2/1999). Per WET guidance, all NPDES permits
issued to Major facilities or any facility discharging "complex" wastewater (contains anything other than
domestic waste) will contain appropriate WET limits and monitoring requirements, with several
exceptions. The State has received prior EPA approval to use an Alternative WET Test Procedure in
NPDES permits, using single concentration screening tests, with multiple dilution follow-up upon a test
failure.
Describe proposed toxicity test requirement: This is a Major POTW, and a chronic WET limit at 83%
effluent will continue on a quarterly frequency.
Mercury Statewide TMDL Evaluation
There is a statewide TMDL for mercury approved by EPA in 2012. The TMDL target was to comply
with EPA's mercury fish tissue criteria (0.3 mg/kg) for human health protection. The TMDL established a
wasteload allocation for point sources of 37 kg/year (81 lb/year), and is applicable to municipals and
industrial facilities with known mercury discharges. Given the small contribution of mercury from point
sources (-2% of total load), the TMDL emphasizes mercury minimization plans (MMPs) for point source
control. Municipal facilities > 2 MGD and discharging quantifiable levels of mercury (>1 ng/1) will
receive an MMP requirement. Industrials are evaluated on a case -by -case basis, depending if mercury is a
pollutant of concern. Effluent limits may also be added if annual average effluent concentrations exceed
the WQBEL value (based on the NC WQS of 12 ng/1) and/or if any individual value exceeds a TBEL
value of 47 ng/1
Table 4. Mercury Effluent Data Summary
2019
2020
2021
2022
2023
# of Samples
13
13
13
13
12
Annual Average Conc. n /L
1.2
0.7
0.6
0.79
0.94
Maximum Conc., n /L
5.1
1.1
0.8
1.78
3.39
TBEL, n /L
47
WQBEL, n /L
14.5
Describe proposed permit actions based on mercury evaluation: Since no annual average mercury
concentration exceeded the WQBEL, and no individual mercury sample exceeded the TBEL, no mercury
limit is required. Since the facility is > 2.0 MGD and reported quantifiable levels of mercury (> 1 ng/1),
the mercury minimization plan (MMP) condition has been maintained. Charlotte Water submitted their
MMP with their 2022 Pretreatment Annual Report.
Other TMDL/Nutrient Management Strategy Considerations
If applicable, describe any other TMDLs/Nutrient Management Strategies and their implementation
within this permit: A fecal coliform TMDL was established in February 2002 and the permit contains a
1000/100 mL fecal coliform daily maximum. On February 22, 2023, during the preparation of the
Page 9 of 16

NC0024970 McAlpine Creek WWMF permit renewal, the Division contacted South Carolina's
Department of Health and Environmental Control (DHEC) regarding whether the daily maximum fecal
coliform requirements under the TMDL were sufficient in protecting the South Carolina E. coli standard,
as the discharge is above the SC/NC border. During their evaluation, SCDHEC considered the
NC0024970 McAlpine Creek WWMF, NC0024937 Sugar Creek WRRF and NC0024945 Irwin Creek
WRRF discharges. On April 5, 2023, SCDHEC informed the Division that based on the NC TMDL and
the actual effluent data, they do not object to the limits for the 3 NC facilities based on fecal coliform
bacteria as the indicator. As such, the fecal coliform limits have been maintained.
A bubble limit for total phosphorus is included for Irwin Creek WRRF, Sugar Creek WRRF, and
McAlpine Creek WWMF. As stipulated by the 2002 Settlement Agreement between Charlotte -
Mecklenburg Utilities (CMU), the South Carolina Department of Health and Environmental Control (SC
DHEC) and the North Carolina Division of Water Quality (NC-DWQ), now North Carolina Division of
Water Resources, Charlotte Water's McAlpine Creek WWMF, Sugar Creek WRRF and Irwin Creek
WRRF must comply with a combined 12 month rolling average limit of 826.0 lbs/day as of February 28,
2006.
Charlotte Water has asked the Division to revise the Sugar, Irwin, and McAlpine Creek permits to
improve the uniformity of their nutrient conditions. As outlined in the 2021 internal Memorandum
"Charlotte Water Permits — Proposed Uniform Nutrient Conditions" (attached), changes are proposed to
the nutrient language and permit conditions for each of these permits to apply more consistent
terminology, units of measure, and parameter codes for the various measures of TP, apply consistent
methods for calculation of TN and TP loads and require reporting of interim calculation results, to make it
easier to see how the final results were derived.
Proposed changes include:
• Section A.(L): Added Total Monthly Flow (TMF) reporting, created separate rows for TP
concentration and mass, applied new parameter names in the table and footnotes to improve
clarity, provided clearer linkage between the limits page, footnotes, and the other TP special
conditions.
• Special Condition A.(7.): Applied the new parameter names and added linkage to the limits page
and calculations condition.
• Special Condition A.(8.): Applied the new terminology and described the calculations for each
measure of TP used on the limits page. Clarified how the combined TP loads would be calculated
and where they would be reported.
The changes will not affect the TN and TP limits or monitoring requirements for the facilities.
Other WOBEL Considerations
If applicable, describe any other parameters of concern evaluated for WQBELs: The bubble limit for total
phosphorus was analyzed for Irwin Creek WRRF, Sugar Creek WRRF, and McAlpine Creek WWMF.
There were no compliance concerns for the period analyzed (January 2018- August 2022) and the three
facilities stayed below their total phosphorus rolling average bubble limit.
As required by Session Law 2018-5, Senate Bill 99, Section 13.1(r), every applicant shall submit
documentation of any additional pollutants for which there are certified methods with the permit
application if their discharge is anticipated. The list of pollutants may be found in 40 CFR Part 136,
which is incorporated by reference. Charlotte Water informed the Division that "no additional parameters
have been identified in the effluent and no chemical addendum sheets are necessary."
Page 10 of 16

If applicable, describe any special actions (HQW or ORW) this receiving stream and classification shall
comply with in order to protect the designated waterbody: NA
If applicable, describe any compliance schedules proposed for this permit renewal in accordance with
15A NCAC 2H 0107( c)(2)(B), 40CFR 122.47, and EPA May 2007 Memo: NA
If applicable, describe any water quality standards variances proposed in accordance with NCGS 143-
215.3(e) and 15A NCAC 2B.0226 for this permit renewal: NA
7. Technology -Based Effluent Limitations (TBELs)
Municipals
Are concentration limits in the permit at least as stringent as secondary treatment requirements (30 mg/l
BODS/TSS for Monthly Average, and 45 mg/l for BODS/TSS for Weekly Average). YES
If NO, provide a justification for alternative limitations (e.g., waste stabilization pond). NA
Are 85% removal requirements for CBOD51TSS included in the permit? YES
If NO, provide a justification (e.g., waste stabilization pond). NA
8. Antidegradation Review (New/Expanding Discharge):
The objective of an antidegradation review is to ensure that a new or increased pollutant loading will not
degrade water quality. Permitting actions for new or expanding discharges require an antidegradation
review in accordance with 15A NCAC 213.0201. Each applicant for a new/expanding NPDES permit
must document an effort to consider non -discharge alternatives per 15A NCAC 21-1.0105(c)(2). In all
cases, existing instream water uses and the level of water quality necessary to protect the existing use is
maintained and protected.
If applicable, describe the results of the antidegradation review, including the Engineering Alternatives
Analysis (EAA) and any water quality modeling results: NA
9. Antibacksliding Review:
Sections 402(o)(2) and 303(d)(4) of the CWA and federal regulations at 40 CFR 122.44(1) prohibit
backsliding of effluent limitations in NPDES permits. These provisions require effluent limitations in a
reissued permit to be as stringent as those in the previous permit, with some exceptions where limitations
may be relaxed (e.g., based on new information, increases in production may warrant less stringent TBEL
limits, or WQBELs may be less stringent based on updated RPA or dilution).
Are any effluent limitations less stringent than previous permit (YESNO): YES
If YES, confirm that antibacksliding provisions are not violated: Based on the reasonable potential
analysis indicating no reasonable potential for surface water excursions above applicable state water
quality standards, total silver, total copper and total chromium monitoring and total cyanide limits and
monitoring have been removed from the permit.
10. Monitoring Requirements
Monitoring frequencies for NPDES permitting are established in accordance with the following
regulations and guidance: 1) State Regulation for Surface Water Monitoring, 15A NCAC 213.0500; 2)
NPDES Guidance, Monitoring Frequency for Toxic Substances (7/15/2010 Memo); 3) NPDES Guidance,
Reduced Monitoring Frequencies for Facilities with Superior Compliance (10/22/2012 Memo); 4) Best
Professional Judgement (BPJ). Per US EPA (Interim Guidance, 1996), monitoring requirements are not
considered effluent limitations under Section 402(o) of the Clean Water Act, and therefore anti -
backsliding prohibitions would not be triggered by reductions in monitoring frequencies.
For instream monitoring, refer to Section 4.
Charlotte Water was granted 2/week monitoring for CBOD, ammonia, TSS and fecal coliform based on
2012 DWR Guidance Regarding the Reduction of Monitoring Frequencies in NPDES Permits for
Page 11 of 16

Exceptionally Performing Facilities during their 2017 renewal. Charlotte Water has requested
continuation of this monitoring frequency reduction as part of their renewal application. The last three
years of the facility's data for these parameters have been reviewed in accordance with the criteria
outlined in the guidance. Based on this review, 2/week monitoring frequency has been maintained for
CBOD, ammonia, TSS and fecal coliform.
To identify PFAS concentrations in waters classified as Water Supply (WS) waters, monitoring
requirements are to be implemented in permits with pretreatment programs that discharge to WS waters.
While there are no WS waters designated by the Division downstream of the discharge, the discharge
point is upstream of the border between North Carolina and South Carolina. Since all waters in South
Carolina are deemed suitable for drinking water uses with appropriate treatment, and to ensure PFAS
contamination does not cross State lines, and as the Irwin Creek WRRF has a pretreatment program,
monitoring of PFAS chemicals has been added to the permit. Currently, EPA Method 1633 is in its 4`h
draft form and not yet published in the Federal Register as a final methodology. As the Irwin Creek
WRRF accepts influent wastewater from several industrial facilities that are potential sources of PFAS via
the approved pretreatment program, and since an EPA method for sampling and analyzing PFAS in
wastewater is not currently available, influent and post -filtration PFAS monitoring has been added to the
permit at a quarterly frequency using the Draft Method 1633. Upon evaluation of laboratory availability
and capability to perform the draft analytical method, it was determined that the sampling may be
conducted using the 3rd draft method 1633 or more recent. Sampling using the draft method shall take
effect the first full calendar quarter following 6 months after the effective date of the permit to provide
Charlotte Water time to select a laboratory, develop a contract, and begin collecting samples. Effective 6
months after EPA has a final wastewater method in 40 CFR136 published in the Federal Register,
Charlotte Water shall conduct effluent monitoring using the Final Method 1633 and is no longer required
to conduct influent and post -filtration monitoring.
In addition to monitoring at the wastewater management facility, Charlotte Water shall identify and
monitor SIUs suspected of discharging PFAS compounds within 6 months of the permit effective date.
Charlotte Water shall update their Industrial Waste Survey- (IWS) to identify indirect dischargers of
PFAS contributing to concentrations experienced at the Irwin Creek WRRF. A summary of information
learned during this process will be provided as part of the 2024 Pretreatment Annual Report (PAR).
Within 6 months of completion of the IWS, Charlotte Water shall begin sampling of indirect dischargers
identified as potential PFAS sources. Sampling conducted at SIUs and indirect dischargers shall also be
conducted at a quarterly frequency. This is a summary of the PFAS requirements. For a detailed outline of
the specific PFAS requirements, see Special Condition A.(10.) PFAS Monitoring Requirements.
As the Irwin Creek WRRF accepts influent wastewater from several industrial facilities that are potential
sources of 1,4-dioxane via the approved pretreatment program, as no additional sampling has been
conducted for 1,4-dioxane at this facility as identified in the chemical addendum submitted by Charlotte
Water, and as the facility discharges above the NC/SC state border line, monthly effluent 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.
The statement, "There shall be no discharge of floating solids or visible foam in other than trace
amounts," was removed during the 2017 renewal. This statement has been standard language in NPDES
permits since the program's inception and is still used widely by state and federal permitting authorities.
Because it is subjective, it is hardly suitable as the basis for an enforcement action; instead, we would rely
on the permittee's monitoring reports to establish and quantify any limits exceedances. Part of its value is
that it provides a quick measure of effluent quality and possible water quality impacts. A DWR inspector
who notices such an issue at a discharge can address the matter while on site rather than waiting days or
Page 12 of 16

weeks for effluent monitoring to be reported. In addition, there is also a concern of the presence of
emerging contaminants in visible foams. Therefore, this condition should be maintained in NPDES
permits. As such, the statement has been added back into the permit in Section A.(1.).
11. Electronic Reporting Requirements
The US EPA NPDES Electronic Reporting Rule was finalized on December 21, 2015. Effective
December 21, 2016, NPDES regulated facilities are required to submit Discharge Monitoring Reports
(DMRs) electronically. While NPDES regulated facilities would initially be required to submit additional
NPDES reports electronically effective December 21, 2020, EPA extended this deadline from December
21, 2020, to December 21, 2025. The current compliance date, effective January 4, 2021, was extended as
a final regulation change published in the November 2, 2020 Federal Register. This permit contains the
requirements for electronic reporting, consistent with Federal requirements.
12.Summary of Proposed Permitting Actions:
Table 5. Current Permit Conditions and Proposed Changes Outfall 001
Parameter
Current Permit
Proposed Change
Basis for Condition/Change
Flow
MA 15.0 MGD
No change
15A NCAC 2B .0505
Total Monthly
No requirement
Monitor and
For calculation of TN and TP loadings
Flow
Report Monthly
CBOD5
Summer:
No change
WQBEL. 1995 Level B model, Surface
MA 5.0 mg/1
Water Monitoring, 2012 DWR Guidance
WA 7.5 mg/1
Regarding the Reduction of Monitoring
Winter:
Frequencies in NPDES Permits for
MA 10.0 mg/l
Exceptionally Performing Facilities
WA 15.0 mg/1
Monitor and report 2/Week
NH3-N
Summer:
No change
WQBEL. 2022 WLA review; Surface
MA 1.2 mg/1
Water Monitoring, 2012 DWR Guidance
WA 3.6 mg/1
Regarding the Reduction of Monitoring
Winter:
Frequencies in NPDES Permits for
MA 2.3 mg/1
Exceptionally Performing Facilities
WA 6.9 mg/l
Monitor and report 2/Week
TSS
MA 30.0 mg/1
No change
WQBEL. 1995 Level B model, Surface
WA 45.0 mg/1
Water Monitoring, 2012 DWR Guidance
Monitor and report 2/Week
Regarding the Reduction of Monitoring
Frequencies in NPDES Permits for
Exceptionally Performing Facilities
Fecal coliform
MA 200 /100ml
Add instream
WQBEL. State WQ standard, 15A
WA 400 /100ml
monitoring at
NCAC 213 .0200; 2002 TMDL for fecal,
DM 1000/100ml
upstream location
results in DM; Surface Water
Monitor and report 2/Week
ICI and
Monitoring, 2012 DWR Guidance
downstream
Regarding the Reduction of Monitoring
location SC 1 —
Frequencies in NPDES Permits for
issued in the
Exceptionally Performing Facilities;
McAlpine Creek
Instream monitoring review and 2022
WWMF
Integrated Report — Exceeding criteria
NC0024970
for fecal coliform; Instream requirements
January 1, 2024
to be added to the requirements listed in
renewal
NC0024970 McAlpine Creek WWTP
Page 13 of 16

Turbidity
No requirement
Add instream
2022 Integrated Report — Exceeding
monitoring at
criteria for turbidity. To be added to the
upstream location
requirements listed in NC0024970
ICI and
McAlpine Creek WWTP — instream only
downstream
due to effluent TSS being reported at low
location SC 1—
values
issued in the
McAlpine Creek
WWMF
NC0024970
January 1, 2024
renewal
DO
> 6 mg/1
No change
WQBEL. 1995 Level B model; Surface
Monitor and report Daily
Water Monitoring, 15A NCAC 2B. 0500
pH
6 — 9 SU
No change
WQBEL. State WQ standard, 15A
Monitor and report Daily
NCAC 2B .0200; Surface Water
Monitoring, 15A NCAC 2B. 0500
Conductivity
Monitor and report Daily
No change
Surface Water Monitoring, 15A NCAC
2B. 0500
Temperature
Monitor and report Daily
No change
Surface Water Monitoring, 15A NCAC
2B. 0500
Total Residual
No requirement
DM 17 ug/L
WQBEL. 2022 WLA review and Surface
Chlorine
Monitor and
Water Monitoring, 15A NCAC 2B. 0500
report Daily
— only required if chlorination used
Total Nitrogen
Monitor and report
No change
Surface Water Monitoring, 15A NCAC
Monthly
2B. 0500
TKN
No requirement
Monitor and
For calculation of Total Nitrogen
report Monthly
NO3+NO2
No requirement
Monitor and
For calculation of Total Nitrogen
report Monthly
Total
826.0 lbs/day bubble limit
No change; Add
WQBEL. Required TP nutrient limits per
Phosphorus
for Irwin Creek WRRF,
separate row for
2002 permitting strategy agreement with
Sugar Creek WRRF, and
lb/mo and lb/yr
Charlotte -Mecklenburg Utilities (CMU),
McAlpine Creek WWMF
reporting
the South Carolina Department of Health
Monitor and report
and Environmental Control (SC DHEC)
Monthly
and the North Carolina Division of Water
Quality (NC-DWQ); Surface Water
Monitoring, 15A NCAC 2B. 0500
Total Hardness
Quarterly monitoring
No change
Hardness -dependent dissolved metals
Upstream (managed in
water quality standards approved in 2016
NC0024970 McAlpine
Creek WWMF permit) and
in Effluent
Total Silver
Monitor and report
Remove
Based on results of RPA; All values non -
Quarterly
requirement
detect < I ug/L - no monitoring required
Total Copper
Monitor and report
Remove
Based on results of RPA; No RP,
Quarterly
requirement
Predicted Max < 50% of Allowable Cw -
No Monitoring required
Page 14 of 16

Total
Monitor and report
Remove
Based on results of RPA; No monitoring
Chromium
Monthly
requirement
required if all Total Chromium samples
are < 5 µg/L or Pred. max for Total Cr is
< allowable Cw for Cr V
Total Cyanide
MA 6.1 ug/L
Remove
Based on results of RPA; All values non -
DM 25.9 ug/L
requirement
detect < 10 ug/L - no monitoring required
Monitor and report
Monthly
Total Phenolic
Monitor and report
Based on results of RPA; No RP ,
Compounds
Quarterly
No change
Predicted Max > 50 /o of Allowable Cw -
a 1 Quarterly Monitoring
Monitor and
Report Monthly
1,4-dioxane
No requirement
and reopener
Based on PT Program industrial
condition; 24-
facilities linked to 1,4-dioxane
month sampling
reassessment
See Special
Condition A.(10.)
Evaluation of HAS contribution:
PFAS
No requirement
PFAS Monitoring
pretreatment facility; Discharge above
Requirements
NC/SC border
Toxicity Test
Chronic limit, 83% effluent
No change
WQBEL. No toxics in toxic amounts.
15A NCAC 2B.0200 and 15A NCAC
213.0500
Effluent
Three times per permit
No change;
40 CFR 122
Pollutant Scan
cycle
conducted in
2025, 2026, 2027
Mercury
MMP Special Condition
No change; revise
WQBEL. Consistent with 2012
Minimization
wording towards
Statewide Mercury TMDL
Plan (MMP)
its maintenance
Implementation.
Electronic
Electronic Reporting
No change
In accordance with EPA Electronic
Reporting
Special Condition
Reporting Rule 2015.
MGD — Million gallons per day, MA - Monthly Average, WA — Weekly Average, DM — Daily Max
13. Public Notice Schedule:
Permit to Public Notice: xx/xx/xxxx
Per 15A NCAC 2H .0109 & .0111, The Division will receive comments for a period of 30 days following
the publication date of the public notice. Any request for a public hearing shall be submitted to the
Director within the 30 days comment period indicating the interest of the party filing such request and the
reasons why a hearing is warranted.
14. NPDES Division Contact
If you have any questions regarding any of the above information or on the attached permit, please
contact Nick Coco at [phone] or via email at [e-mail].
15. Fact Sheet Addendum (if applicable):
Were there any changes made since the Draft Permit was public noticed (Yes/No): NO
If Yes, list changes and their basis below: NA
Page 15 of 16

16. Fact Sheet Attachments (if applicable):
• RPA Spreadsheet Summary
• NPDES Implementation of Instream Dissolved Metals Standards — Freshwater Standards
• NH3/TRC WLA Calculations
• BOD & TSS Removal Rate Calculations
• Mercury TMDL Calculations
• WET Testing and Self -Monitoring Summary
• Compliance Inspection Report
• 2003 TRC Policy
• 2021 Internal Memo Charlotte Water Permits — Proposed Uniform Nutrient Conditions
• Requested Additional Information
• Email Correspondence with Charlotte Water
• Email Correspondence with SCDHEC
• Email Correspondence with EPA, Office of Information Management — CROMERR
• NCDEQ CROMERR Approval Letter
Page 16 of 16

Freshwater RPA - 95% Probability/95% Confidence Using Metal Translators
MAXIMUM DATA POINTS = 58
REQUIRED DATA ENTRY
Table 1. Project Information
❑ CHECK IF HQW OR ORW WQS
Facility Name
WWTP/WTP Class
NPDES Permit
Outfall
Flow, Ow (MGD)
Receiving Stream
HUC Number
Stream Class
❑ Apply WS Hardness WQC
7Q10s (cfs)
7Q10w (cfs)
30Q2 (cfs)
QA (cfs)
1 Q10s (cfs)
_Effluent Hardness
Upstream Hardness
_Combined Hardness Chronic_
Combined Hardness Acute
Data Source(s)
❑ CHECK TO APPLY MODEL
Irwin Creek WWTP
IV
NCO024945
001
15.000
Irwin Creek
03050103
C
4.90
7.70
9.90
43.00
4.09
123.24 mg/L (Avg)
75.69 mg/L (Avg)
--------114_96mg/L—_____
116.13 mg/LNor-
Par01
Par02
Par03
Par04
Par05
Par06■
Par07
Par08
Par09
Par10
Par11
Par12
Par13
Par14
Par15
Par16
Par17
Par18
Par19
Par20
Par21
Par22
Par23
Par24
Table 2. Parameters of Concern
Name Was Type Chronic Modifier Acute PQL Units
Arsenic
Aquactic Life
C
150
FW
340
ug/L
Arsenic
Human Health
Water Supply
C
10
HH/WS
N/A
ug/L
Beryllium
Aquatic Life
NC
6.5
FW
65
ug/L
Cadmium
Aquatic Life
NC
1.8667
FW
12.3616
ug/L
Chlorides
Aquatic Life
NC
230
FW
mg/L
Chlorinated Phenolic Compounds
Water supply
NC
1
A
ug/L
Total Phenolic Compounds
Aquatic Life
NC
300
A
ug/L
Chromium III
Aquatic Life
NC
410.7541
FW
3183.8714
ug/L
Chromium VI
Aquatic Life
NC
11
FW
16
pg/L
Chromium, Total
Aquatic Life
NC
N/A
FW
N/A
pg/L
Copper
Aquatic Life
NC
29.0248
FW
44.5113
ug/L
Cyanide
Aquatic Life
NC
5
FW
22
10
ug/L
Fluoride
Aquatic Life
NC
1,800
FW
ug/L
Lead
Aquatic Life
NC
15.9231
FW
413.0986
ug/L
Mercury
Aquatic Life
NC
12
FW
0.5
ng/L
Molybdenum
Human Health
NC
2000
HH
ug/L
Nickel
Aquatic Life
NC
135.3583
FW
1229.1129
pg/L
Nickel
Water Supply
NC
25.0000
WS
N/A
pg/L
Selenium
Aquatic Life
NC
5
FW
56
ug/L
Silver
Aquatic Life
NC
0.06
FW
4.1601
ug/L
Zinc
Aquatic Life
NC
461.6671
FW
461.8457
ug/L
24945 rpa, input
1 /3/2024

REASONABLE POTENTIAL ANALYSIS
H1
Effluent Hardness
Use "PASTE SPECIAL
Values"then"COPY".
H2
Maximum data points
= 58
Date
Data
BDL=1/2DL
Results
1
7/8/2019
130
130
Std Dev.
14.4942
1
2
7/9/2019
130
130
Mean
123.2414
2
3
8/7/2019
110
110
C.V.
0.1176
3
4
9/5/2019
110
110
n
58
4
5
10/4/2019
98
98
10th Per value
110.00 mg/L
5
6
11/2/2019
120
120
Average Value
123.24 mg/L
6
7
12/8/2019
140
140
Max. Value
170.00 mg/L
7
8
1 /6/2020
130
130
8
9
2/4/2020
120
120
9
10
3/4/2020
130
130
10
11
4/2/2020
150
150
11
12
4/15/2020
130
130
12
13
5/8/2020
120
120
13
14
6/12/2020
120
120
14
15
7/12/2020
120
120
15
16
8/3/2020
110
110
16
17
9/15/2020
120
120
17
18
10/7/2020
120
120
18
19
11 /5/2020
110
110
19
20
12/4/2020
110
110
20
21
1 /9/2021
120
120
21
22
2/7/2021
130
130
22
23
3/8/2021
140
140
23
24
4/6/2021
140
140
24
25
5/12/2021
120
120
25
26
6/3/2021
120
120
26
27
7/9/2021
160
160
27
28
7/14/2021
150
150
28
29
8/14/2021
150
150
29
30
9/12/2021
170
170
30
31
10/11 /2021
130
130
31
32
11 /16/2021
130
130
32
33
12/15/2021
140
140
33
34
1 /6/2022
120
120
34
35
2/4/2022
130
130
35
36
3/5/2022
120
120
36
37
4/3/2022
110
110
37
38
5/9/2022
120
120
38
39
6/7/2022
100
100
39
40
7/20/2022
120
120
40
41
8/11 /2022
120
120
41
42
9/9/2022
100
100
42
43
10/5/2022
100
100
43
44
10/15/2022
140
140
44
45
11 /13/2022
110
110
45
46
12/12/2022
120
120
46
47
1 /10/2023
120
120
47
48
1 /18/2023
130
130
48
49
2/8/2023
110
110
49
50
3/9/2023
120
120
50
51
4/14/2023
120
120
51
52
5/6/2023
120
120
52
53
6/4/2023
120
120
53
54
7/10/2023
110
110
54
55
8/8/2023
120
120
55
56
9/6/2023
120
120
56
57
10/12/2023
110
110
57
58
11 /3/2023
110
110
58
Use 'PASTE SPECIAL
Values"then"COPY"
Upstream Hardness
Maximum data points
= 58
Date Data
BDL=1/2DL
Results
6/17/2019
89
89
Std Dev.
13.5129
7/18/2019
77
77
Mean
75.6852
8/7/2019
85
85
C.V.
0.1785
9/12/2019
77
77
n
54
10/8/2019
66
66
10th Per value
57.30 mg/L
11/14/2019
73
73
Average Value
75.69 mg/L
12/19/2019
91
91
Max. Value
100.00 mg/L
1 /9/2020
98
98
2/4/2020
95
95
3/16/2020
100
100
4/6/2020
100
100
5/11/2020
96
96
6/ 1 /2020
100
100
7/7/2020
73
73
8/3/2020
79
79
9/15/2020
76
76
10/5/2020
79
79
11 /2/2020
63
63
12/8/2020
94
94
1/11/2021
84
84
2/3/2021
85
85
3/8/2021
92
92
4/12/2021
83
83
5/17/2021
86
86
6/14/2021
70
70
7/6/2021
65
65
8/9/2021
64
64
9/7/2021
68
68
10/4/2021
57
57
11 /9/2021
55
55
12/14/2021
53
53
1/19/2022
68
68
2/9/2022
74
74
3/2/2022
73
73
4/13/2022
90
90
5/9/2022
78
78
6/1/2022
79
79
7/20/2022
65
65
8/8/2022
57
57
9/7/2022
53
53
10/17/2022
58
58
11 /9/2022
60
60
12/12/2022
71
71
1/10/2023
73
73
2/8/2023
80
80
3/8/2023
95
95
4/3/2023
80
80
5/1/2023
72
72
6/20/2023
53
53
7/3/2023
75
75
8/1/2023
63
63
9/5/2023
69
69
10/17/2023
65
65
11/7/2023
63
63
24945 rpa, data
1 1 /3/2024

REASONABLE POTENTIAL ANALYSIS
Par01 & Par02
Arsenic
Date
Data
BDL=1/2DL
1 8/7/2019
<
5
2.5
2 9/5/2019
<
5
2.5
3 10/4/2019
<
5
2.5
4 11 /2/2019
<
5
2.5
5 12/8/2019
<
5
2.5
6 1 /6/2020
<
5
2.5
7 2/4/2020
<
5
2.5
8 3/4/2020
<
5
2.5
9 4/2/2020
<
5
2.5
10 4/15/2020
<
5
2.5
11 5/8/2020
<
5
2.5
12 6/12/2020
<
5
2.5
13 7/12/2020
<
5
2.5
14 8/3/2020
<
5
2.5
15 9/15/2020
<
5
2.5
16 10/7/2020
<
5
2.5
17 11 /5/2020
<
5
2.5
18 12/4/2020
<
5
2.5
19 1 /9/2021
<
5
2.5
20 2/7/2021
<
5
2.5
21 3/8/2021
<
5
2.5
22 4/6/2021
<
5
2.5
23 5/12/2021
<
5
2.5
24 6/3/2021
<
5
2.5
25 7/9/2021
<
5
2.5
26 7/14/2021
<
5
2.5
27 8/14/2021
<
5
2.5
28 9/12/2021
<
5
2.5
29 10/11/2021
<
5
2.5
30 11/16/2021
<
5
2.5
31 12/15/2021
<
5
2.5
32 1 /6/2022
<
5
2.5
33 2/4/2022
<
5
2.5
34 3/5/2022
<
5
2.5
35 4/3/2022
<
5
2.5
36 5/9/2022
<
5
2.5
37 6/7/2022
<
5
2.5
38 7/20/2022
<
5
2.5
39 8/11/2022
<
5
2.5
40 9/9/2022
<
5
2.5
41 10/5/2022
<
5
2.5
42 10/15/2022
<
5
2.5
43 10/31 /2022
<
5
2.5
44 11/13/2022
<
5
2.5
45 12/12/2022
<
5
2.5
46 1/10/2023
<
5
2.5
47 1/18/2023
<
5
2.5
48 2/8/2023
<
5
2.5
49 3/9/2023
<
5
2.5
50 4/14/2023
<
5
2.5
51 5/6/2023
<
5
2.5
52 6/4/2023
<
5
2.5
53 7/10/2023
<
5
2.5
54 7/20/2023
<
5
2.5
55 8/8/2023
<
5
2.5
56 9/6/2023
<
5
2.5
57 10/12/2023
<
5
2.5
58 11 /3/2023
<
5
2.5
Use "PASTE SPECIAL
Values" then "COPY' .
Maximum data points
= 58
Results
Std Dev.
0.0000
Mean
2.5000
C.V.
0.0000
n
58
Mult Factor = 1.00
Max. Value 2.5 ug/L
Max. Pred Cw 2.5 ug/L
-2-
24945 rpa, data
1 /3/2024

REASONABLE POTENTIAL ANALYSIS
Par03
Date Data
1 4/15/2020 <
2 7/14/2021 <
3 10/5/2022 <
4 1/18/2023 <
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
Beryllium
BDL=1/2DL
Results
2 1
Std Dev.
2 1
Mean
2 1
C.V. (default)
2 1
n
Mult Factor =
Max. Value
Max. Fred Cw
Use"PASTE SPECIAL Par04
Values" then "COPY".
Maximum data points
= 58
1.0000
0.6000
4
2.59
1.00 ug/L
2.59 ug/L
Date Data
1 8/7/2019 <
2 9/5/2019 <
3 10/4/2019 <
4 11 /2/2019 <
5 12/8/2019 <
6 1 /6/2020 <
7 2/4/2020 <
8 3/4/2020 <
9 4/2/2020 <
10 4/15/2020 <
11 5/8/2020 <
12 6/12/2020 <
13 7/12/2020 <
14 8/3/2020 <
15 9/15/2020 <
16 10/7/2020 <
17 11 /5/2020 <
18 12/4/2020 <
19 1 /9/2021 <
20 2/7/2021 <
21 3/8/2021 <
22 4/6/2021 <
23 5/12/2021 <
24 6/3/2021 <
25 7/9/2021 <
26 7/14/2021 <
27 8/14/2021 <
28 9/12/2021 <
29 10/11/2021 <
30 11/16/2021 <
31 12/15/2021 <
32 1 /6/2022 <
33 2/4/2022 <
34 3/5/2022 <
35 4/3/2022 <
36 5/9/2022 <
37 6/7/2022 <
38 7/20/2022 <
39 8/11/2022 <
40 9/9/2022 <
41 10/5/2022 <
42 10/15/2022 <
43 10/31 /2022 <
44 11/13/2022 <
45 12/12/2022 <
46 1/10/2023 <
47 1/18/2023 <
48 2/8/2023 <
49 3/9/2023 <
50 4/14/2023 <
51 5/6/2023 <
52 6/4/2023 <
53 7/10/2023 <
54 7/20/2023 <
55 8/8/2023 <
56 9/6/2023 <
57 10/12/2023 <
58 11/3/2023 <
Cadmium
BDL=1/2DL
Results
1
0.5
Std Dev.
0.5
0.25
Mean
0.5
0.25
C.V.
0.5
0.25
n
0.5
0.25
0.5
0.25
Mult Factor =
0.5
0.25
Max. Value
0.5
0.25
Max. Fred Cw
0.5
0.25
0.5
0.25
0.5
0.25
0.5
0.25
0.5
0.25
0.5
0.25
0.5
0.25
0.5
0.25
0.5
0.25
0.5
0.25
0.5
0.25
0.5
0.25
0.5
0.25
0.5
0.25
0.5
0.25
0.5
0.25
0.5
0.25
0.5
0.25
0.5
0.25
0.5
0.25
0.5
0.25
0.5
0.25
0.5
0.25
0.5
0.25
0.5
0.25
0.5
0.25
0.5
0.25
0.5
0.25
0.5
0.25
0.5
0.25
0.5
0.25
0.5
0.25
0.5
0.25
0.5
0.25
0.5
0.25
0.5
0.25
0.5
0.25
0.5
0.25
0.5
0.25
0.5
0.25
0.5
0.25
0.5
0.25
0.5
0.25
0.5
0.25
0.5
0.25
0.5
0.25
0.5
0.25
0.5
0.25
0.5
0.25
0.5
0.25
Use 'PASTE SPECIAL
Values" then "COPY"
Maximum data points
= 58
0.2543
0.1291
58
1.00
0.500 ug/L
0.500 ug/L
-3-
24945 rpa, data
1 /3/2024

REASONABLE POTENTIAL ANALYSIS
Par07
Total Phenolic Compounds
Date
Data
BDL=1/2DL
Results
1
6/12/2019
<
50
25
Std Dev.
2
8/14/2019
<
50
25
Mean
3
10/9/2019
<
50
25
C.V.
4
12/11/2019
<
50
25
n
5
2/12/2020
<
50
25
6
4/15/2020
<
50
25
Mult Factor =
7
4/21/2020
<
50
25
Max. Value
8
6/17/2020
<
50
25
Max. Fred Cw
9
8/12/2020
<
50
25
10
10/20/2020
<
50
25
11
12/9/2020
<
50
25
12
2/3/2021
<
50
25
13
4/14/2021
<
50
25
14
6/9/2021
<
50
25
15
7/14/2021
<
50
25
16
8/4/2021
<
50
25
17
10/6/2021
<
50
25
18
12/22/2021
<
50
25
19
2/9/2022
<
50
25
20
4/13/2022
<
50
25
21
6/15/2022
<
50
25
22
8/3/2022
<
50
25
23
10/5/2022
<
50
25
24
10/12/2022
<
50
25
25
12/7/2022
<
50
25
26
1 /18/2023
186
186
27
2/15/2023
<
50
25
28
4/19/2023
58
58
29
6/14/2023
<
50
25
30
8/16/2023
<
50
25
31
10/4/2023
87
87
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
Use "PASTE SPECIAL Par10
Values" then "COPY".
Maximum data points
= 58
33.2581
0.9306
31
1.28
186.0 ug/L
238.1 ug/L
Date Data
1 8/7/2019 <
2 9/5/2019 <
3 10/4/2019 <
4 11 /2/2019 <
5 12/8/2019 <
6 1 /6/2020 <
7 2/4/2020 <
8 3/4/2020 <
9 4/2/2020 <
10 4/15/2020 <
11 5/8/2020 <
12 6/12/2020 <
13 7/12/2020 <
14 8/3/2020 <
15 9/15/2020 <
16 10/7/2020 <
17 11 /5/2020 <
18 12/4/2020 <
19 1 /9/2021 <
20 2/7/2021 <
21 3/8/2021 <
22 4/6/2021 <
23 5/12/2021 <
24 6/3/2021 <
25 7/9/2021 <
26 7/14/2021 <
27 8/14/2021 <
28 9/12/2021 <
29 10/11/2021 <
30 11/16/2021 <
31 12/15/2021 <
32 1 /6/2022 <
33 2/4/2022 <
34 3/5/2022 <
35 4/3/2022 <
36 5/9/2022 <
37 6/7/2022 <
38 7/20/2022 <
39 8/11/2022 <
40 9/9/2022 <
41 10/5/2022 <
42 10/15/2022 <
43 10/31 /2022 <
44 11/13/2022 <
45 12/12/2022 <
46 1/10/2023 <
47 1/18/2023 <
48 2/8/2023 <
49 3/9/2023 <
50 4/14/2023 <
51 5/6/2023 <
52 6/4/2023 <
53 7/10/2023 <
54 7/20/2023 <
55 8/8/2023 <
56 9/6/2023 <
57 10/12/2023 <
58 11/3/2023 <
Chromium, Total
BDL=1/2DL
Results
5
2.5
Std Dev.
5
2.5
Mean
5
2.5
C.V.
5
2.5
n
5
2.5
5
2.5
Mult Factor =
5
2.5
Max. Value
5
2.5
Max. Fred Cw
5
2.5
5
2.5
5
2.5
5
2.5
5
2.5
5
2.5
5
2.5
5
2.5
5
2.5
5
2.5
5
2.5
5
2.5
5
2.5
5
2.5
5
2.5
5
2.5
5
2.5
5
2.5
5
2.5
5
2.5
5
2.5
5
2.5
5
2.5
5
2.5
5
2.5
5
2.5
5
2.5
5
2.5
5
2.5
5
2.5
5
2.5
5
2.5
5
2.5
5
2.5
5
2.5
5
2.5
5
2.5
5
2.5
5
2.5
5
2.5
5
2.5
5
2.5
5
2.5
5
2.5
5
2.5
5
2.5
5
2.5
5
2.5
5
2.5
5
2.5
Use 'PASTE SPECIAL
Values" then "COPY"
Maximum data points
= 58
2.5000
0.0000
58
1.00
2.5 pg/L
2.5 pg/L
-4-
24945 rpa, data
1 /3/2024

REASONABLE POTENTIAL ANALYSIS
Pal
Copper
Date
Data
BDL=1/2DL
1
8/7/2019
2.6
2.6
2
9/5/2019
3
3
3
10/4/2019
2.4
2.4
4
11/2/2019
<
2
1
5
12/8/2019
2.1
2.1
6
1 /6/2020
2.7
2.7
7
2/4/2020
3.2
3.2
8
3/4/2020
3
3
9
4/2/2020
3
3
10
4/15/2020
<
2
1
11
5/8/2020
2.1
2.1
12
6/12/2020
7.6
7.6
13
7/12/2020
2.5
2.5
14
8/3/2020
2.3
2.3
15
9/15/2020
<
2
1
16
10/7/2020
2.5
2.5
17
11/5/2020
2.5
2.5
18
12/4/2020
2.2
2.2
19
1/9/2021
2.5
2.5
20
2/7/2021
3.1
3.1
21
3/8/2021
2.2
2.2
22
4/6/2021
2.6
2.6
23
5/12/2021
2.8
2.8
24
6/3/2021
2.8
2.8
25
7/9/2021
2.4
2.4
26
7/14/2021
2.2
2.2
27
8/14/2021
<
2
1
28
9/12/2021
<
2
1
29
10/11/2021
<
2
1
30
11/16/2021
<
2
1
31
12/15/2021
2.2
2.2
32
1 /6/2022
<
2
1
33
2/4/2022
2.4
2.4
34
3/5/2022
2.2
2.2
35
4/3/2022
<
2
1
36
5/9/2022
2.2
2.2
37
6/7/2022
<
2
1
38
7/20/2022
<
2
1
39
8/11/2022
2.5
2.5
40
9/9/2022
2.6
2.6
41
10/5/2022
<
2
1
42
10/15/2022
<
2
1
43
10/31/2022
<
2
1
44
11/13/2022
<
2
1
45
12/12/2022
<
2
1
46
1/10/2023
<
2
1
47
1/18/2023
<
2
1
48
2/8/2023
<
2
1
49
3/9/2023
<
2
1
50
4/14/2023
<
2
1
51
5/6/2023
3.1
3.1
52
6/4/2023
2.2
2.2
53
7/10/2023
2.3
2.3
54
7/20/2023
2.5
2.5
55
8/8/2023
2.4
2.4
56
9/6/2023
3
3
57
10/12/2023
<
2
1
58
11/3/2023
2.3
2.3
Use "PASTE SPECIAL Par12
Values" then "COPY".
Maximum data points
= 58
Results
Std Dev.
1.0817
Mean
2.0379
C.V.
0.5308
n
58
Mult Factor =
1.00
Max. Value
7.60 ug/L
Max. Fred Cw
7.60 ug/L
Date Data
1 6/3/2019 <
2 7/9/2019 <
3 8/7/2019 <
4 9/5/2019 <
5 10/4/2019 <
6 11 /4/2019 <
7 12/9/2019 <
8 1 /6/2020 <
9 2/4/2020 <
10 3/4/2020 <
11 4/2/2020 <
12 4/15/2020 <
13 5/8/2020 <
14 6/12/2020 <
15 7/13/2020 <
16 8/3/2020 <
17 9/15/2020 <
18 10/7/2020 <
19 11 /5/2020 <
20 12/4/2020 <
21 1 /8/2021 <
22 2/8/2021 <
23 3/8/2021 <
24 4/6/2021 <
25 5/12/2021 <
26 6/3/2021 <
27 7/9/2021 <
28 7/14/2021 <
29 8/13/2021 <
30 9/13/2021 <
31 10/11/2021 <
32 11/16/2021 <
33 12/15/2021 <
34 1 /6/2022 <
35 2/4/2022 <
36 3/4/2022 <
37 4/4/2022 <
38 5/9/2022 <
39 6/7/2022 <
40 7/20/2022 <
41 8/11/2022 <
42 9/9/2022 <
43 10/5/2022 <
44 10/14/2022 <
45 11/14/2022 <
46 12/12/2022 <
47 1/10/2023 <
48 1/18/2023 <
49 2/8/2023 <
50 3/9/2023 <
51 4/14/2023 <
52 5/5/2023 <
53 6/5/2023 <
54 7/10/2023 <
55 8/8/2023 <
56 9/6/2023 <
57 10/12/2023 <
58 11/3/2023 <
Cyanide
BDL=1/2DL
Results
10 5
Std Dev.
10 5
Mean
10 5
C.V.
10 5
n
10 5
10 5
Mult Factor =
10 5
Max. Value
10 5
Max. Pred Cw
10 5
10 5
10 5
10 5
10 5
10 5
10 5
10 5
10 5
10 5
10 5
10 5
10 5
10 5
10 5
10 5
10 5
10 5
10 5
10 5
10 5
10 5
10 5
10 5
10 5
10 5
10 5
10 5
10 5
10 5
10 5
10 5
10 5
10 5
10 5
10 5
10 5
10 5
10 5
10 5
10 5
10 5
10 5
10 5
10 5
10 5
10 5
10 5
10 5
10 5
Use 'PASTE SPECIAL
Values" then "COPY"
Maximum data points
= 58
5.00
0.0000
58
1.00
5.0 ug/L
5.0 ug/L
-5-
24945 rpa, data
1 /3/2024

REASONABLE POTENTIAL ANALYSIS
Par14
Par16
Use "PASTE SPECIAL
Use "PASTE SPECIAL
Lead
Values" then "COPY".
Molybdenum
Values" then "COPY".
Maximum data points
Maximum data points
= 58
= 58
Date
BDL=1/2DL
Results
Date
Data
BDL=1/2DL
Results
1
8/7/2019
< 5
2.5
Std Dev.
0.0000
1
8/7/2019
<
5
2.5
Std Dev.
0.3677
2
9/5/2019
< 5
2.5
Mean
2.5000
2
9/5/2019
<
5
2.5
Mean
2.5483
3
10/4/2019
< 5
2.5
C.V.
0.0000
3
10/4/2019
<
5
2.5
C.V.
0.1443
4
11/2/2019
< 5
2.5
n
58
4
11/2/2019
<
5
2.5
n
58
5
12/8/2019
< 5
2.5
5
12/8/2019
<
5
2.5
6
1/6/2020
< 5
2.5
Mult Factor =
1.00
6
1/6/2020
<
5
2.5
Mult Factor =
1.00
7
2/4/2020
< 5
2.5
Max. Value
2.500 ug/L
7
2/4/2020
<
5
2.5
Max. Value
5.3 ug/L
8
3/4/2020
< 5
2.5
Max. Fred Cw
2.500 ug/L
8
3/4/2020
<
5
2.5
Max. Fred Cw
5.3 ug/L
9
4/2/2020
< 5
2.5
9
4/2/2020
<
5
2.5
10
4/15/2020
< 5
2.5
10
4/15/2020
<
5
2.5
11
5/8/2020
< 5
2.5
11
5/8/2020
<
5
2.5
12
6/12/2020
< 5
2.5
12
6/12/2020
<
5
2.5
13
7/12/2020
< 5
2.5
13
7/12/2020
<
5
2.5
14
8/3/2020
< 5
2.5
14
8/3/2020
<
5
2.5
15
9/15/2020
< 5
2.5
15
9/15/2020
<
5
2.5
16
10/7/2020
< 5
2.5
16
10/7/2020
<
5
2.5
17
11/5/2020
< 5
2.5
17
11/5/2020
<
5
2.5
18
12/4/2020
< 5
2.5
18
12/4/2020
<
5
2.5
19
1/9/2021
< 5
2.5
19
1/9/2021
<
5
2.5
20
2/7/2021
< 5
2.5
20
2/7/2021
<
5
2.5
21
3/8/2021
< 5
2.5
21
3/8/2021
<
5
2.5
22
4/6/2021
< 5
2.5
22
4/6/2021
<
5
2.5
23
5/12/2021
< 5
2.5
23
5/12/2021
<
5
2.5
24
6/3/2021
< 5
2.5
24
6/3/2021
<
5
2.5
25
7/9/2021
< 5
2.5
25
7/9/2021
<
5
2.5
26
7/14/2021
< 5
2.5
26
7/14/2021
<
5
2.5
27
8/14/2021
< 5
2.5
27
8/14/2021
<
5
2.5
28
9/12/2021
< 5
2.5
28
9/12/2021
<
5
2.5
29
10/11/2021
< 5
2.5
29
10/11/2021
<
5
2.5
30
11/16/2021
< 5
2.5
30
11/16/2021
<
5
2.5
31
12/15/2021
< 5
2.5
31
12/15/2021
<
5
2.5
32
1/6/2022
< 5
2.5
32
1/6/2022
<
5
2.5
33
2/4/2022
< 5
2.5
33
2/4/2022
<
5
2.5
34
3/5/2022
< 5
2.5
34
3/5/2022
<
5
2.5
35
4/3/2022
< 5
2.5
35
4/3/2022
<
5
2.5
36
5/9/2022
< 5
2.5
36
5/9/2022
<
5
2.5
37
6/7/2022
< 5
2.5
37
6/7/2022
<
5
2.5
38
7/20/2022
< 5
2.5
38
7/20/2022
<
5
2.5
39
8/11/2022
< 5
2.5
39
8/11/2022
5.3
5.3
40
9/9/2022
< 5
2.5
40
9/9/2022
<
5
2.5
41
10/5/2022
< 5
2.5
41
10/5/2022
<
5
2.5
42
10/15/2022
< 5
2.5
42
10/15/2022
<
5
2.5
43
10/31/2022
< 5
2.5
43
10/31/2022
<
5
2.5
44
11/13/2022
< 5
2.5
44
11/13/2022
<
5
2.5
45
12/12/2022
< 5
2.5
45
12/12/2022
<
5
2.5
46
1/10/2023
< 5
2.5
46
1/10/2023
<
5
2.5
47
1/18/2023
< 5
2.5
47
1/18/2023
<
5
2.5
48
2/8/2023
< 5
2.5
48
2/8/2023
<
5
2.5
49
3/9/2023
< 5
2.5
49
3/9/2023
<
5
2.5
50
4/14/2023
< 5
2.5
50
4/14/2023
<
5
2.5
51
5/6/2023
< 5
2.5
51
5/6/2023
<
5
2.5
52
6/4/2023
< 5
2.5
52
6/4/2023
<
5
2.5
53
7/10/2023
< 5
2.5
53
7/10/2023
<
5
2.5
54
7/20/2023
< 5
2.5
54
7/20/2023
<
5
2.5
55
8/8/2023
< 5
2.5
55
8/8/2023
<
5
2.5
56
9/6/2023
< 5
2.5
56
9/6/2023
<
5
2.5
57
10/12/2023
< 5
2.5
57
10/12/2023
<
5
2.5
58
11/3/2023
< 5
2.5
58
11/3/2023
<
5
2.5
24945 rpa, data
-6- 1/3/2024

REASONABLE POTENTIAL ANALYSIS
Par17 & Par18
Nickel
Date
Data
BDL=1/2DL
Results
1
8/7/2019
5.5
5.5
Std Dev.
2
9/5/2019
3.3
3.3
Mean
3
10/4/2019
9.7
9.7
C.V.
4
11 /2/2019
3.6
3.6
n
5
12/8/2019
2.5
2.5
6
1/6/2020
<
2
1
Mult Factor =
7
2/4/2020
3.8
3.8
Max. Value
8
3/4/2020
3.3
3.3
Max. Pred Cw
9
4/2/2020
3.1
3.1
10
4/15/2020
2.7
2.7
11
5/8/2020
2.8
2.8
12
6/12/2020
2.7
2.7
13
7/12/2020
2.8
2.8
14
8/3/2020
3.6
3.6
15
9/15/2020
2.5
2.5
16
10/7/2020
3.6
3.6
17
11 /5/2020
3.6
3.6
18
12/4/2020
3.2
3.2
19
1 /9/2021
2.4
2.4
20
2/7/2021
3
3
21
3/8/2021
2.2
2.2
22
4/6/2021
3.1
3.1
23
5/12/2021
2.6
2.6
24
6/3/2021
3.4
3.4
25
7/9/2021
4
4
26
7/14/2021
4.1
4.1
27
8/14/2021
3.9
3.9
28
9/12/2021
3.7
3.7
29
10/11/2021
2.9
2.9
30
11/16/2021
2.9
2.9
31
12/15/2021
3.4
3.4
32
1 /6/2022
3.1
3.1
33
2/4/2022
3.9
3.9
34
3/5/2022
2.7
2.7
35
4/3/2022
4.3
4.3
36
5/9/2022
3.4
3.4
37
6/7/2022
3
3
38
7/20/2022
3
3
39
8/11/2022
2.7
2.7
40
9/9/2022
2.9
2.9
41
10/5/2022
2.3
2.3
42
10/15/2022
2.3
2.3
43
10/31 /2022
<
2
1
44
11/13/2022
<
2
1
45
12/12/2022
<
2
1
46
1/10/2023
2.1
2.1
47
1/18/2023
2.2
2.2
48
2/8/2023
2.9
2.9
49
3/9/2023
2.9
2.9
50
4/14/2023
3.6
3.6
51
5/6/2023
3.1
3.1
52
6/4/2023
<
2
1
53
7/10/2023
2.2
2.2
54
7/20/2023
2.7
2.7
55
8/8/2023
2.2
2.2
56
9/6/2023
3.3
3.3
57
10/12/2023
3.4
3.4
58
11 /3/2023
4.7
4.7
Use "PASTE SPECIAL Par19
Values" then "COPY" .
Maximum data points
= 58
3.0655
0.4080
58
1.00
9.7 pg/L
9.7 pg/L
Date Data
1 8/7/2019 <
2 9/5/2019 <
3 10/4/2019 <
4 11 /2/2019 <
5 12/8/2019 <
6 1 /6/2020 <
7 2/4/2020 <
8 3/4/2020 <
9 4/2/2020 <
10 4/15/2020 <
11 5/8/2020 <
12 6/12/2020 <
13 7/12/2020 <
14 8/3/2020 <
15 9/15/2020 <
16 10/7/2020 <
17 11 /5/2020 <
18 12/4/2020 <
19 1/9/2021 <
20 2/7/2021 <
21 3/8/2021 <
22 4/6/2021 <
23 5/12/2021 <
24 6/3/2021 <
25 7/9/2021 <
26 7/14/2021 <
27 8/14/2021 <
28 9/12/2021 <
29 10/11/2021 <
30 11/16/2021 <
31 12/15/2021 <
32 1 /6/2022 <
33 2/4/2022 <
34 3/5/2022 <
35 4/3/2022 <
36 5/9/2022 <
37 6/7/2022 <
38 7/20/2022 <
39 8/11/2022 <
40 9/9/2022 <
41 10/5/2022 <
42 10/15/2022 <
43 10/31/2022 <
44 11/13/2022 <
45 12/12/2022 <
46 1/10/2023 <
47 1/18/2023 <
48 2/8/2023 <
49 3/9/2023 <
50 4/14/2023 <
51 5/6/2023 <
52 6/4/2023 <
53 7/10/2023 <
54 7/20/2023 <
55 8/8/2023 <
56 9/6/2023 <
57 10/12/2023 <
581 11/3/2023 <
Selenium
BDL=1/2DL
Results
5 2.5
Std Dev.
5 2.5
Mean
5 2.5
C.V.
5 2.5
n
5 2.5
5 2.5
Mult Factor =
5 2.5
Max. Value
5 2.5
Max. Pred Cw
5 2.5
5 2.5
5 2.5
5 2.5
5 2.5
5 2.5
5 2.5
5 2.5
5 2.5
5 2.5
5 2.5
5 2.5
5 2.5
5 2.5
5 2.5
5 2.5
5 2.5
5 2.5
5 2.5
5 2.5
5 2.5
5 2.5
5 2.5
5 2.5
5 2.5
5 2.5
5 2.5
5 2.5
5 2.5
5 2.5
5 2.5
5 2.5
5 2.5
5 2.5
5 2.5
5 2.5
5 2.5
5 2.5
5 2.5
5 2.5
5 2.5
5 2.5
5 2.5
5 2.5
5 2.5
5 2.5
5 2.5
5 2.5
5 2.5
5 2.5
Use -PASTE
SPECIAL -Values"
then "COPY".
Maximum data
points = 58
2.5000
0.0000
58
1.00
2.5 ug/L
2.5 ug/L
24945 rpa, data
-7- 1 /3/2024

REASONABLE POTENTIAL ANALYSIS
Par20
Par21
Use "PASTE SPECIAL
Use "PASTE SPECIAL
Silver
Values" then "COPY".
Zinc
Values" then "COPY".
Maximum data points
Maximum data points
= 58
= 58
Date
Data
BDL=1/2DL
Results
Date Data
BDL=1/2DL
Results
1
8/7/2019
<
1
0.5
Std Dev.
0.0000
1
8/7/2019
38
38
Std Dev.
7.2579
2
9/5/2019
<
1
0.5
Mean
0.5000
2
9/5/2019
41
41
Mean
41.9138
3
10/4/2019
<
1
0.5
C.V.
0.0000
3
10/4/2019
56
56
C.V.
0.1732
4
11/2/2019
<
1
0.5
n
58
4
11/2/2019
31
31
n
58
5
12/8/2019
<
1
0.5
5
12/8/2019
45
45
6
1/6/2020
<
1
0.5
Mult Factor =
1.00
6
1/6/2020
34
34
Mult Factor =
1.00
7
2/4/2020
<
1
0.5
Max. Value
0.500 ug/L
7
2/4/2020
44
44
Max. Value
57.0 ug/L
8
3/4/2020
<
1
0.5
Max. Fred Cw
0.500 ug/L
8
3/4/2020
48
48
Max. Fred Cw
57.0 ug/L
9
4/2/2020
<
1
0.5
9
4/2/2020
43
43
10
4/15/2020
<
1
0.5
10
4/15/2020
33
33
11
5/8/2020
<
1
0.5
11
5/8/2020
33
33
12
6/12/2020
<
1
0.5
12
6/12/2020
47
47
13
7/12/2020
<
1
0.5
13
7/12/2020
51
51
14
8/3/2020
<
1
0.5
14
8/3/2020
51
51
15
9/15/2020
<
1
0.5
15
9/15/2020
41
41
16
10/7/2020
<
1
0.5
16
10/7/2020
52
52
17
11/5/2020
<
1
0.5
17
11/5/2020
57
57
18
12/4/2020
<
1
0.5
18
12/4/2020
47
47
19
1/9/2021
<
1
0.5
19
1/9/2021
46
46
20
2/7/2021
<
1
0.5
20
2/7/2021
40
40
21
3/8/2021
<
1
0.5
21
3/8/2021
32
32
22
4/6/2021
<
1
0.5
22
4/6/2021
34
34
23
5/12/2021
<
1
0.5
23
5/12/2021
44
44
24
6/3/2021
<
1
0.5
24
6/3/2021
43
43
25
7/9/2021
<
1
0.5
25
7/9/2021
48
48
26
7/14/2021
<
1
0.5
26
7/14/2021
42
42
27
8/14/2021
<
1
0.5
27
8/14/2021
49
49
28
9/12/2021
<
1
0.5
28
9/12/2021
55
55
29
10/11/2021
<
1
0.5
29
10/11/2021
49
49
30
11/16/2021
<
1
0.5
30
11/16/2021
41
41
31
12/15/2021
<
1
0.5
31
12/15/2021
47
47
32
1/6/2022
<
1
0.5
32
1/6/2022
37
37
33
2/4/2022
<
1
0.5
33
2/4/2022
45
45
34
3/5/2022
<
1
0.5
34
3/5/2022
38
38
35
4/3/2022
<
1
0.5
35
4/3/2022
30
30
36
5/9/2022
<
1
0.5
36
5/9/2022
51
51
37
6/7/2022
<
1
0.5
37
6/7/2022
39
39
38
7/20/2022
<
1
0.5
38
7/20/2022
38
38
39
8/11/2022
<
1
0.5
39
8/11/2022
50
50
40
9/9/2022
<
1
0.5
40
9/9/2022
41
41
41
10/5/2022
<
1
0.5
41
10/5/2022
43
43
42
10/15/2022
<
1
0.5
42
10/15/2022
43
43
43
10/31/2022
<
1
0.5
43
10/31/2022
46
46
44
11/13/2022
<
1
0.5
44
11/13/2022
36
36
45
12/12/2022
<
1
0.5
45
12/12/2022
27
27
46
1/10/2023
<
1
0.5
46
1/10/2023
25
25
47
1/18/2023
<
1
0.5
47
1/18/2023
34
34
48
2/8/2023
<
1
0.5
48
2/8/2023
32
32
49
3/9/2023
<
1
0.5
49
3/9/2023
41
41
50
4/14/2023
<
1
0.5
50
4/14/2023
35
35
51
5/6/2023
<
1
0.5
51
5/6/2023
45
45
52
6/4/2023
<
1
0.5
52
6/4/2023
37
37
53
7/10/2023
<
1
0.5
53
7/10/2023
41
41
54
7/20/2023
<
1
0.5
54
7/20/2023
46
46
55
8/8/2023
<
1
0.5
55
8/8/2023
38
38
56
9/6/2023
<
1
0.5
56
9/6/2023
35
35
57
10/12/2023
<
1
0.5
57
10/12/2023
49
49
58
11/3/2023
<
1
0.5
58
11/3/2023
47
47
24945 rpa, data
-8- 1/3/2024

Irwin Creek WWTP
NCO024945 Freshwater RPA - 95% Probability/95% Confidence Using Metal Translators
MAXIMUM DATA POINTS = 58
Qw (MGD) = 15.0000
WWTP/WTP Class: IV
1Q10S (cfs) = 4.09
IWC% @ 1Q10S = 85.04023409
7Q10S (cfs) = 4.90
IWC% @ 7Q10S = 82.59325044
7Q10W (cfs) = 7.70
IWC% @ 7Q10W = 75.12116317
30Q2 (cfs) = 9.90
IWC% @ 30Q2 = 70.13574661
Avg. Stream Flow, QA (cfs) = 43.00
IW%C @ QA = 35.09433962
Receiving Stream: Irwin Creek HUC 03050103
Stream Class: C
Outfall 001
Qw=15MGD
COMBINED HARDNESS (ma/L)
Acute=116.13 mg/L
Chronic = 114.96 mg/L
PARAMETER
NC STANDARDS OR EPA CRITERIA
fn
REASONABLE POTENTIAL RESULTS
RECOMMENDED ACTION
TYPE
J
a
D
Chronic Applied Acute
n # Det. Max Pred Cw Allowable Cw
Standard
Acute (FW): 399.8
Arsenic
C
150 FW(7Q10s) 340
ug/L
58 0
2.5
Chronic (FW): 181.6
No RP, Predicted Max < 50% of Allowable Cw - No
Max M_DL_= 5
Monitoring required
Arsenic
C
10 HH/WS(Qavg)
ug/L
NO DETECTS
Chronic(HH): 28.5
Max MDL = 5
Acute: 76.43
Beryllium
NC
6.5 FW(7Q10s) 65
ug/L
4 0
2.59
Note: n < 9
C.V. (default)
Chronic: 7.87
No RP, Predicted Max < 50% of Allowable Cw - No
Limited data set
NO DETECTS
Max MDL = 2
Monitoring required
Acute: 14.536
Cadmium
NC
1.8667 FW(7Q10s) 12.3616
ug/L
58 0
0.500
_ _ _ _
Chronic: 2.260
_ _ _ _ _ _ _ _ _ _ _ _ _ _
No RP, Predicted Max < 50% of Allowable Cw - No
NO DETECTS
Max MDL = 1
Monitoring required
Acute: NO WQS
Total Phenolic Compounds
NC
300 A(30Q2)
ug/L
31 3
238.1
_
Chronic: 427.7
_
No RP, Predicted Max >_ 50% of Allowable Cw
No value > Allowable Cw
apply Quarterly Monitoring
Acute: 3,744.0
Chromium III
NC
410.7541 FW(7Q10s) 3183.8714
µg/L
0 0
N/A
Chronic: -----497.3--
---------------------------
Acute: 18.8
Chromium VI
NC
11 FW(7Q10s) 16
µg/L
0 0
N/A
_ _ _ _ _
Chronic:---- 13.3 --
---------------------------
Chromium, Total
NC
µg/L
58 0
2.5
Max reported value = 2.5
a: No monitoring required if all Total Chromium
samples are < 5 pg/L or Pred. max for Total Cr is <
allowable Cw for Cr VI.
NO DETECTS
Max MDL = 5
Acute: 52.34
Copper
NC
29.0248 FW(7Q10s) 44.5113
ug/L
58 36
7.60
_ _ _ _ _ _ _ _
_ _ _ _ _ _ _ _ _ _ _ _ _ _
Chronic: 35.14
No RP, Predicted Max < 50% of Allowable Cw - No
No value > Allowable Cw
Monitoring required
Acute: 25.9
Cyanide
NC
5 FW(7Q10s) 22
10
ug/L
58 0
5.0
_ _ _ _ _ _
_ _ _ _ _ _ _ _ _
Chronic: 6.1
All values non -detect < 10 ug/L - no monitoring
NO DETECTS
Max MDL = 10
required
Acute: 485.768
Lead
NC
15.9231 FW(7Q10s) 413.0986
ug/L
58 0
2.500
_ _ _ _ _ _ _ _ _ _
Chronic 19.279
_ _ _ _ _ _ _ _ _ _ _ _ _ _
No RP, Predicted Max < 50% of Allowable Cw - No
24945 rpa, rpa
Page 1 of 2 1/3/2024

Irwin Creek WWTP I Outfall 001
NCO024945 Freshwater RPA - 95% Probability/95% Confidence Using Metal Translators Qw = 15 MGD
NO DETECTS
Max MDL = 5
Monitoring required
Acute: NO WQS
Molybdenum
NC
2000 HH(7Q10s)
ug/L
58 1
5.3
_ _ _ _
_ _ _ _ _ _ _ _ _ _ _ _ _ _
Chronic: 2,421.5
No RP, Predicted Max < 50% of Allowable Cw - No
No value > Allowable Cw
Monitoring required
Acute (FW): 1,445.3
Nickel
NC
135.3583 FW(7Q10s) 1229.1129
µg/L
58 53
9.7
Chronic (FW): 163.9
No RP, Predicted Max < 50% of Allowable Cw - No
No value > Allowable Cw
Monitoring required
Nickel
NC
25.0000 WS(7Q10s)
µg/L
Chronic (WS): 30.3
No value > Allowable Cw
Acute: 65.9
Selenium
NC
5 FW(7Q10s) 56
ug/L
58 0
2.5
Chronic: 6.1
No RP, Predicted Max < 50% of Allowable Cw - No
NO DETECTS
Max MDL = 5
Monitoring required
Acute: 4.892
Silver
NC
0.06 FW(7Q10s) 4.1601
ug/L
58 0
0.500
_ _ _ _ _ _
Chronic: 0.073
_ _ _ _ _ _ _ _ _ _ _ _
All values non -detect < 1 ug/L - no monitoring
NO DETECTS
Max MDL = 1
required
Acute: 543.1
Zinc
NC
461.6671 FW(7Q10s) 461.8457
ug/L
58 58
57.0
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
Chronic: 559.0 No RP, Predicted Max < 50% of Allowable Cw - No
No value > Allowable Cw Monitoring required
24945 rpa, rpa
Page 2 of 2 1/3/2024

Permit No. NC0024945
NPDES Implementation of Instream Dissolved Metals Standards - Freshwater Standards
The NC 2007-2015 Water Quality Standard (WQS) Triennial Review was approved by the NC
Environmental Management Commission (EMC) on November 13, 2014. The US EPA subsequently
approved the WQS revisions on April 6, 2016, with some exceptions. Therefore, metal limits in draft
permits out to public notice after April 6, 2016 must be calculated to protect the new standards - as
approved.
Table 1. NC Dissolved Metals Water Q ality Standards/A uatic Life Protection
Parameter
Acute FW, µg/1
(Dissolved)
Chronic FW, µg/l
(Dissolved)
Acute SW, µg/1
(Dissolved)
Chronic SW, µg/l
(Dissolved)
Arsenic
340
150
69
36
Beryllium
65
6.5
---
---
Cadmium
Calculation
Calculation
40
8.8
Chromium III
Calculation
Calculation
---
---
Chromium VI
16
11
1100
50
Copper
Calculation
Calculation
4.8
3.1
Lead
Calculation
Calculation
210
8.1
Nickel
Calculation
Calculation
74
8.2
Silver
Calculation
0.06
1.9
0.1
Zinc
Calculation
Calculation
90
81
Table 1 Notes:
1. FW= Freshwater, SW= Saltwater
2. Calculation = Hardness dependent standard
3. Only the aquatic life standards listed above are expressed in dissolved form. Aquatic life
standards for Mercury and selenium are still expressed as Total Recoverable Metals due to
bioaccumulative concerns (as are all human health standards for all metals). It is still necessary
to evaluate total recoverable aquatic life and human health standards listed in 15A NCAC
213.0200 (e.g., arsenic at 10 µg/1 for human health protection; cyanide at 5 µg/L and fluoride at
1.8 mg/L for aquatic life protection).
Table 2. Dissolved Freshwater Standards for Hardness -Dependent Metals
The Water Effects Ratio (WER) is equal to one unless determined otherwise under 15A
NCAC 02B .0211 Subparagraph (11)(d)
Metal
NC Dissolved Standard, µg/I
Cadmium, Acute
WER* f 1.136672-[ln hardness] (0.041838)} e^ f0.9151 [ln hardness]-3.14851
Cadmium, Acute Trout waters
WER* f 1.136672-[ln hardness] (0.041838)} e^ f 0.9151 [ln hardness] -3.623 61
Cadmium, Chronic
WER* f 1.101672-[ln hardness] (0.041838)} • e^ f 0.7998[ln hardness]-4.4451)
Chromium III, Acute
WER*0.316 e^ f 0.8190[ln hardness]+3.7256}
Chromium III, Chronic
WER*0.860 e^ f 0.8190[ln hardness]+0.6848}
Copper, Acute
WER*0.960 e^ f 0.9422[1n hardness] -1.700f
Copper, Chronic
WER*0.960 e^ f 0.8545[ln hardness]-1.702f
Lead, Acute
WER* f 1.46203-[ln hardness](0.145712)} • e^ f 1.273[ln hardness]-1.460)
Lead, Chronic
WER* f 1.46203-[ln hardness](0.145712)} • e^ f 1.273[ln hardness]-4.705)
Nickel, Acute
WER*0.998 e^ f 0.8460[ln hardness]+2.255)
Nickel, Chronic
WER*0.997 e^ f 0.8460[ln hardness]+0.0584)
Page 1 of 4

Permit No. NCO024945
Silver, Acute
WER*0.85 • e^{1.72[ln hardness]-6.59}
Silver, Chronic
Not applicable
Zinc, Acute
WER*0.978 e^{0.8473[In hardness]+0.884}
Zinc, Chronic
WER*0.986 e^{0.8473[In hardness]+0.884}
General Information on the Reasonable Potential Analysis (RPA)
The RPA process itself did not change as the result of the new metals standards. However, application of
the dissolved and hardness -dependent standards requires additional consideration in order to establish the
numeric standard for each metal of concern of each individual discharge.
The hardness -based standards require some knowledge of the effluent and instream (upstream) hardness
and so must be calculated case -by -case for each discharge.
Metals limits must be expressed as `total recoverable' metals in accordance with 40 CFR 122.45(c). The
discharge -specific standards must be converted to the equivalent total values for use in the RPA
calculations. We will generally rely on default translator values developed for each metal (more on that
below), but it is also possible to consider case -specific translators developed in accordance with
established methodology.
RPA Permitting Guidance/WOBELs for Hardness -Dependent Metals - Freshwater
The RPA is designed to predict the maximum likely effluent concentrations for each metal of concern,
based on recent effluent data, and calculate the allowable effluent concentrations, based on applicable
standards and the critical low -flow values for the receiving stream.
If the maximum predicted value is greater than the maximum allowed value (chronic or acute), the
discharge has reasonable potential to exceed the standard, which warrants a permit limit in most cases. If
monitoring for a particular pollutant indicates that the pollutant is not present (i.e. consistently below
detection level), then the Division may remove the monitoring requirement in the reissued permit.
To perform a RPA on the Freshwater hardness -dependent metals the Permit Writer compiles the
following information:
• Critical low flow of the receiving stream, 7Q 10 (the spreadsheet automatically calculates
the 1 Q 10 using the formula 1 Q 10 = 0.843 (s7Q 10, cfs) 0.993
• Effluent hardness and upstream hardness, site -specific data is preferred
• Permitted flow
• Receiving stream classification
2. In order to establish the numeric standard for each hardness -dependent metal of concern and for
each individual discharge, the Permit Writer must first determine what effluent and instream
(upstream) hardness values to use in the equations.
The permit writer reviews DMR's, Effluent Pollutant Scans, and Toxicity Test results for any
hardness data and contacts the Permittee to see if any additional data is available for instream
hardness values, upstream of the discharge.
If no hardness data is available, the permit writer may choose to do an initial evaluation using a
default hardness of 25 mg/L (CaCO3 or (Ca + Mg)). Minimum and maximum limits on the
hardness value used for water quality calculations are 25 mg/L and 400 mg/L, respectively.
If the use of a default hardness value results in a hardness -dependent metal showing reasonable
potential, the permit writer contacts the Permittee and requests 5 site -specific effluent and
upstream hardness samples over a period of one week. The RPA is rerun using the new data.
Page 2 of 4

Permit No. NCO024945
The overall hardness value used in the water quality calculations is calculated as follows:
Combined Hardness (chronic)
_ (Permitted Flow, cfs *Avg. Effluent Hardness, mg/L,L+ (s7Q10, cfs *Avg. Upstream Hardness, m /g_L)
(Permitted Flow, cfs + s7Q 10, cfs)
The Combined Hardness for acute is the same but the calculation uses the IQ 10 flow.
3. The permit writer converts the numeric standard for each metal of concern to a total recoverable
metal, using the EPA Default Partition Coefficients (DPCs) or site -specific translators, if any
have been developed using federally approved methodology.
EPA default partition coefficients or the "Fraction Dissolved" converts the value for
dissolved metal at laboratory conditions to total recoverable metal at in -stream
ambient conditions. This factor is calculated using the linear partition coefficients
found in The Metals Translator: Guidance for Calculating a Total Recoverable
Permit Limit from a Dissolved Criterion (EPA 823-B-96-007, June 1996) and the
equation:
Cdiss - 1
Ctotal I + { [Kpo] [ss(l+a)] [10-6] }
Where:
ss = in -stream suspended solids concentration [mg/1], minimum of 10 mg/L used,
and
Kpo and a = constants that express the equilibrium relationship between dissolved
and adsorbed forms of metals. A list of constants used for each hardness -dependent
metal can also be found in the RPA program under a sheet labeled DPCs.
4. The numeric standard for each metal of concern is divided by the default partition coefficient (or
site -specific translator) to obtain a Total Recoverable Metal at ambient conditions.
In some cases, where an EPA default partition coefficient translator does not exist (ie. silver), the
dissolved numeric standard for each metal of concern is divided by the EPA conversion factor to
obtain a Total Recoverable Metal at ambient conditions. This method presumes that the metal is
dissolved to the same extent as it was during EPA's criteria development for metals. For more
information on conversion factors see the June, 1996 EPA Translator Guidance Document.
5. The RPA spreadsheet uses a mass balance equation to determine the total allowable concentration
(permit limits) for each pollutant using the following equation:
Ca = (s7Q 10 + Qw) (Cwgs) (s7Q 10) (Cb)
Qw
Where: Ca = allowable effluent concentration (µg/L or mg/L)
Cwqs = NC Water Quality Standard or federal criteria (µg/L or mg/L)
Cb = background concentration: assume zero for all toxicants except NH3* (µg/L or mg/L)
Qw = permitted effluent flow (cfs, match s7Q 10)
s7Q 10 = summer low flow used to protect aquatic life from chronic toxicity and human
health through the consumption of water, fish, and shellfish from noncarcinogens (cfs)
* Discussions are on -going with EPA on how best to address background concentrations
Flows other than s7Q 10 may be incorporated as applicable:
IQ 10 = used in the equation to protect aquatic life from acute toxicity
Page 3 of 4

Permit No. NC0024945
QA = used in the equation to protect human health through the consumption of water,
fish, and shellfish from carcinogens
30Q2 = used in the equation to protect aesthetic quality
6. The permit writer enters the most recent 2-3 years of effluent data for each pollutant of concern.
Data entered must have been taken within four and one-half years prior to the date of the permit
application (40 CFR 122.21). The RPA spreadsheet estimates the 95th percentile upper
concentration of each pollutant. The Predicted Max concentrations are compared to the Total
allowable concentrations to determine if a permit limit is necessary. If the predicted max exceeds
the acute or chronic Total allowable concentrations, the discharge is considered to show
reasonable potential to violate the water quality standard, and a permit limit (Total allowable
concentration) is included in the permit in accordance with the U.S. EPA Technical Support
Document for Water Quality -Based Toxics Control published in 1991.
7. When appropriate, permit writers develop facility specific compliance schedules in accordance
with the EPA Headquarters Memo dated May 10, 2007 from James Hanlon to Alexis Strauss on
40 CFR 122.47 Compliance Schedule Requirements.
The Total Chromium NC WQS was removed and replaced with trivalent chromium and
hexavalent chromium Water Quality Standards. As a cost savings measure, total chromium data
results may be used as a conservative surrogate in cases where there are no analytical results
based on chromium III or VI. In these cases, the projected maximum concentration (95th %) for
total chromium will be compared against water quality standards for chromium III and
chromium VI.
9. Effluent hardness sampling and instream hardness sampling, upstream of the discharge, are
inserted into all permits with facilities monitoring for hardness -dependent metals to ensure the
accuracy of the permit limits and to build a more robust hardness dataset.
10. Hardness and flow values used in the Reasonable Potential Analysis for this permit included:
Parameter
Value
Comments (Data Source)
Average Effluent Hardness (mg/L)
[Total as, CaCO3 or (Ca+Mg)]
123.23
Average from June 2019 to
November 2023 samples
Average Upstream Hardness (mg/L)
[Total as, CaCO3 or (Ca+Mg)]
75.69
Average from June 2019 to
November 2023 samples
7Q10 summer (cfs)
4.9
Historical; Previous Fact Sheet
1Q10 (cfs)
4.09
Calculated in RPA
Permitted Flow (MGD)
15.0
NPDES Files
Date: 1/3/2024
Permit Writer: Nick Coco
Page 4 of 4

NCO024945
Irwin Creek WWTP
1/3/2024
CBOD monthly
removal rate
TSS
monthly removal
rate
Month
RR (%)
Month
RR (%)
Month
RR (%)
Month
RR (%)
June-19
99.35
December-21
99.41
June-19
99.12
December-21
99.12
July-19
99.31
January-22
99.34
July-19
99.11
January-22
98.97
August-19
99.29
February-22
99.37
August-19
99.17
February-22
99.25
September-19
99.36
March-22
99.21
September-19
99.16
March-22
99.04
October-19
99.34
April-22
99.25
October-19
99.12
April-22
99.08
November-19
99.27
May-22
99.29
November-19
98.99
May-22
99.00
December-19
99.32
June-22
99.34
December-19
99.08
June-22
98.98
January-20
99.23
July-22
99.37
January-20
98.74
July-22
99.16
February-20
99.18
August-22
99.36
February-20
99.05
August-22
99.05
March-20
99.25
September-22
99.42
March-20
99.34
September-22
99.04
April-20
99.23
October-22
99.44
April-20
99.06
October-22
99.19
May-20
99.14
November-22
99.37
May-20
98.81
November-22
99.09
June-20
99.24
December-22
99.34
June-20
99.05
December-22
99.14
July-20
99.24
January-23
99.28
July-20
99.10
January-23
99.05
August-20
99.25
February-23
99.24
August-20
99.07
February-23
98.75
September-20
99.23
March-23
99.39
September-20
99.02
March-23
99.13
October-20
99.24
April-23
99.35
October-20
99.03
April-23
99.11
November-20
99.26
May-23
99.31
November-20
98.93
May-23
99.00
December-20
99.29
June-23
99.26
December-20
98.94
June-23
98.99
January-21
99.21
July-23
99.30
January-21
98.84
July-23
99.03
February-21
99.06
August-23
99.34
February-21
98.83
August-23
98.98
March-21
99.19
September-23
99.36
March-21
98.93
September-23
99.09
April-21
99.26
October-23
99.38
April-21
98.87
October-23
99.10
May-21
99.31
November-23
99.39
May-21
99.12
November-23
99.20
June-21
99.32
December-23
-
June-21
99.10
December-23
-
July-21
99.28
January-24
-
July-21
98.98
January-24
-
August-21
99.33
February-24
-
August-21
99.00
February-24
-
September-21
99.40
March-24
-
September-21
99.11
March-24
-
October-21
99.35
April-24
-
October-21
99.08
April-24
-
November-21
99.37
May-24
-
November-21
99.11
May-24
-
Overall CBOD
removal rate
99.30
Overall TSS removal
rate
99.04

1/3/24 WQS = 12 ng/L
Facility Name
Irwin Creek WWTP/NC0024945
/Permit No.
Total Mercury 1631E PQL = 0.5 ng/L
Date Modifier Data Entry Value
MERCURY WQBEL/TBEL EVALUATION V:2013-6
No Limit Required
MMP Required
7Q10s = 4.900 cfs WQBEL = 14.53 ng/L
Permitted Flow = 15.000 47 ng/L
6/2/19
5.1
5.1
7/8/19
0.5
0.5
8/6/19
0.6
0.6
9/4/19
0.8
0.8
10/3/19
<
0.5
0.5
11/1/19
<
0.5
0.5
12/7/19
0.7
0.7
1.2 ng/L - Annual Average for 2019
1/5/20
0.6
0.6
2/3/20
0.6
0.6
3/3/20
0.8
0.8
4/1/20
1.1
1.1
4/14/20
1.1
1.1
5/7/20
1
1
6/11/20
0.9
0.9
7/11/20
0.5
0.5
8/6/20
<
0.5
0.5
9/14/20
<
0.5
0.5
10/6/20
0.6
0.6
11/4/20
0.8
0.8
12/3/20
<
0.5
0.5
0.7 ng/L - Annual Average for 2020
1/8/2 1
0.8
0.8
2/6/2 1
0.7
0.7
3/7/2 1
<
0.5
0.5
4/5/2 1
0.6
0.6
5/11/21
<
0.5
0.5
6/2/21
0.55
0.55
7/8/2 1
<
0.5
0.5

7/13/21
0.55
0.55
7/19/21
0.62
0.62
9/11/21
0.59
0.59
10/10/21
<
0.5
0.5
11/15/21
<
0.5
0.5
12/14/21
<
0.5
0.5
0.6 ng/L - Annual Average for 2021
1/5/22
0.82
0.82
2/3/22
0.84
0.84
3/4/22
0.81
0.81
4/2/22
0.81
0.81
5/8/22
0.95
0.95
6/6/22
<
0.5
0.5
7/19/22
<
0.5
0.5
8/10/22
<
0.5
0.5
9/8/22
0.96
0.96
10/4/22
<
0.5
0.5
10/14/22
1.78
1.78
11/12/22
0.67
0.67
12/11/22
0.59
0.59
0.8 ng/L - Annual Average for 2022
1/9/23
0.77
0.77
1/17/23
<
0.5
0.5
2/7/23
3.39
3.39
3/8/23
1.09
1.09
4/13/23
0.67
0.67
5/5/23
0.85
0.85
6/3/23
<
0.5
0.5
7/9/23
0.9
0.9
8/7/23
0.77
0.77
9/5/23
0.69
0.69
10/11/23
0.61
0.61
11/2/23
<
1
0.5
0.9 ng/L - Annual Average for 2023

Irwin Creek WWTP/NC0024945
Mercury Data Statistics (Method 1631E)
2019
2020
2021
2022
# of Samples
7
13
13
13
Annual Average, ng/L
1.2
0.7
0.6
0.79
Maximum Value, ng/L
5.10
1.10
0.80
1.78
TBEL, ng/L
47
WQBEL, ng/L
14.5
2023
12
0.936667
3.39

Reduction in Frequency Evaluation
Facility:
Irwin Creek WWTP
Permit No.
NC0024945
Review period (use 3
11/2020 - 11/2023
yrs)
Approval Criteria: Y/N?
1. Not currently under SOC
Y
2. Not on EPA Quarterly noncompliance report
Y
3. Facility or employees convicted of CWA
violations
N
# of non
Monthly
3-yr mean
# daily
# daily
Reduce
Reduce
Data Review
Units
y
average
50%
(geo mean
< 50%?
200%
samples
o
200%
<15?
samples < 20?
monthly
> 2?
# civil penalty
> 17
Frequency?
average limit
limit
MA
for FC)
MA
>200%
WA
>200%
limit
asessment
Yes No
/ )
violations
CBOD (Weighted)
mg/L
10.625
7.08333
3.5
0
Y
14.2
0
Y
Y
0
N
0
N
Y
TSS
mg/L
45
30
15
1.119251
Y
60
0
0
N
0
N
Y
Ammonia (weighted)
mg/L
1 4.975
1 1.658331
0.8
1 0.0472991
ny
i 3.32
0
Y
0
N
0
N
Y
Fecal Coliform
#/100
1 400
1 200
1 1001
0.6881918
1 Y
800 0 Y
0
N
0
N
Y

NH3/TRC WLA Calculations
Facility: Irwin Creek WWTP
PermitNo. NC0024945
Prepared By: Nick Coco
Enter Design Flow (MGD): 15
Enter s7Q10 (cfs): 4.9
Enter w7Q10 (cfs): 7.7
Total Residual Chlorine (TRC) Ammonia (Summer)
Daily Maximum Limit (ug/1) Monthly Average Limit (mg NH3-N/1)
s7Q10 (CFS)
4.9
s7Q10 (CFS)
4.9
DESIGN FLOW (MGD)
15
DESIGN FLOW (MGD)
15
DESIGN FLOW (CFS)
23.25
DESIGN FLOW (CFS)
23.25
STREAM STD (UG/L)
17.0
STREAM STD (MG/L)
1.0
Upstream Bkgd (ug/1)
0
Upstream Bkgd (mg/1)
0.22
IWC (%)
82.59
IWC (%)
82.59
Allowable Conc. (ug/1)
21
Allowable Conc. (mg/1)
1.2
More stringent than current limit.
Consistent with current limit. Maintain limit.
Apply limit.
Ammonia (Winter)
Monthly Average Limit (mg NH3-N/1)
Fecal Coliform
w7Q10 (CFS)
7.7
Monthly Average Limit:
200/100mI
DESIGN FLOW (MGD)
15
(If DF >331; Monitor)
DESIGN FLOW (CFS)
23.25
(If DF<331; Limit)
STREAM STD (MG/L)
1.8
Dilution Factor (DF)
1.21
Upstream Bkgd (mg/1)
0.22
IWC (%)
75.12
Allowable Conc. (mg/1)
2.3
Consistent with current limit. Maintain limit.
Total Residual Chlorine
1. Cap Daily Max limit at 28 ug/I to protect for acute toxicity
Ammonia (as NH3-N)
1. If Allowable Conc > 35 mg/I, Monitor Only
2. Monthly Avg limit x 3 = Weekly Avg limit (Municipals)
3. Monthly Avg limit x 5 = Daily Max limit (Non-Munis)
If the allowable ammonia concentration is > 35 mg/L, no limit shall be imposed
Fecal Coliform
1. Monthly Avg limit x 2 = 400/100 ml = Weekly Avg limit (Municipals) = Daily Max limit (Non -Muni)

Coco, Nick A
From: Sypolt, Shannon <[e-mail]>
Sent: Monday, February 13, 2023 4:08 PM
To: Coco, Nick A
Cc: Montebello, Michael J; Macomber, Maggie; Lockler, Joseph
Subject: RE: [EXT]RE: [External] RE: Additional Information Request: Irwin & Sugar Creek NPDES Permit
Renewal Applications
Follow Up Flag: Follow up
Flag Status: Flagged
CAUTION: External email. Do not click links or open attachments unless you verify. Send all suspicious email as an attachment to
Report Spam.
Hi Nick,
Per you request below and pertaining to confirmation that our application remains accurate, to the best of our
knowledge, no additional parameters have been sampled for since our original application was submitted. Therefore no
additional parameters have been identified in the effluent and no chemical addendum sheets are necessary. Thank you.
Shannon Sypolt
Water Quality Program Administrator
Environmental Management
CHARLOTTE Vti6TER
4222 Westmont Drive / Charlotte, NC 28217
P: 704-336-4581 / C: 704-634-6984 / charlottewater.org
From: Coco, Nick A <[e-mail]>
Sent: Monday, February 6, 2023 3:59 PM
To: Sypolt, Shannon <[e-mail]>
Cc: Montebello, Michael J<[e-mail]>; Macomber, Maggie
<[e-mail]>; Lockler, Joseph<[e-mail]>
Subject: [EXT]RE: [External] RE: Additional Information Request: Irwin & Sugar Creek NPDES Permit Renewal Applications
Hi Shannon,
Thank you for getting this to us and thank you for the call last week to discuss the status of these permits.
To justify that the application remains accurate with regard to which parameters have been sampled for at each of these
facilities, please verify that no additional parameters have been sampled for, before or after the application was
submitted, and therefore no additional parameters have been identified in the effluents of each plant and no chemical
addendum sheets are necessary.
Thanks again,

Nick Coco, PE (he/him/his)
Engineer 111
NPDES Municipal Permitting Unit
NC DEQ / Division of Water Resources / Water Quality Permitting
Office: [phone]
[e-mail]
"Email is preferred but 1 am available to talk by via Microsoft Teams"
Physical Address: 512 North Salisbury St.,Raleigh, NC, 27604
Mailing Address: 1617 Mail Service Center, Raleigh, NC, 27699-1617
D E Q:>
NORTH CAROLINA -
Department of Environmental Quality
Email correspondence to and from this address is subject to the North
Carolina Public Records Law and may be disclosed to third parties.
From: Sypolt, Shannon<[e-mail]>
Sent: Friday, February 3, 2023 4:57 PM
To: Coco, Nick A <[e-mail]>
Cc: Montebello, Michael J<[e-mail]>; Macomber, Maggie
<Maggie.Malcom [e-mail]>; Lockler, Joseph<[e-mail]>
Subject: [External] RE: Additional Information Request: Irwin & Sugar Creek NPDES Permit Renewal Applications
CAUTION: External email. Do not click links or open attachments unless you verify. Send all suspicious email as an attachment to
Report Spam.
Hi Nick,
Per your request below please see the following additional information:
1) Please see the attached monitoring frequency reduction request summary for Irwin and Sugar Creek
2) 1 have confirmed with our Pretreatment Program Supervisor that no SIU's in our Pretreatment Program have
been sampled for 1,4 Dioxane. Additionally, we have not collected any 1,4 Dioxane samples from Irwin,
Sugar, or McAlpine.
3) Regarding the chemical addendum submission, Charlotte Water believes we have met the requirement
needed to properly submit this information as outlined on NCDWR's website and we have previously
certified our application as being true, accurate, and complete. Please see the information below that we
are referring to:

)E5 Individual PermitApplic2 X I.- SL 2018-5 (5B 99) X I +
C Q i deq.nc.gov/3bout/divisions/water-resources/water-quality-permittingjnpdes-wastewater/npdes-permitting-process/npdes-indiv
ManuTacmring, wafer I reaLment viams, erc. j. IT you are applying Tor a Nvut� [aeneral
click the link found on side bar to the right. Please make sure your application iscomr
submission.
Please submit 1 original and 2 copies of your application package to the following mai
Division of Water Resources
Water Quality Permitting Section - NPDES
1517 Mail Service Center
Raleigh, NC 27699-1617
EPA Updates -All EPA applications below have been updated. As of February 1, 2020, p
any previous versions and use the updated forms below. Tips far filling out the new ap
can be found here. If you completed an application priorto Feburary 1, 2020, please cc
and attach it as an addendum to your application.
Chemical Addendum Form -As required by Session Law 2018-5, Senate Bill99, Sectioi
applicantshall now submit documentation of any additional pollutants forwhich ther
methods with the permit application iftheirdischarge is anticipated. The list of polluti
found in 40 CFR Part 136, which is incorporated by reference. If there are additional po
certified methods to be reported, please submit the Chem icalAddend um to NPDES Af
with you rapplication and, if applicable, list the selected certified analytical method u4
no additional pollutants to report, this form is not required to be included with your al
requirement applies to all NPDES facilities. The Chemical Addendum to NPDES Applk
required for any type of facility with an NPDES permit; depending on whether those ty
are found in your wastewater.

6,2
Certification Sfatement
l cerfify tinder penalty of faun that this document and all atfachrrments were prepared adder my direction or supervision in
accordance with a system designed to assure that qualified personnel property gather and evaluate the information
submitted. Based on my inquiry of the person orpersons who manage the sysforn, or those persons directly responsible
for galher6g the inforration, the information submiffed is, to the best of my knowledge and belief, true, accurate, and
complete. t am aware that there are significant penalties for submilting false information, including the passibility of fine
and imprisonment for bovving violations.
Dame (print or type first and last name)
Official Utle
SiaC6 L)D--1 KJ YLi}`L
-!DOpV
Signature
C-�
Date signed
If you have any questions concerning the information contained in this email, or if you need any further information, just
let me know. Thank you for the opportunity to provide this additional information. Happy Friday!!!
Respectfully,
Shannon Sypolt
Water Quality Program Administrator
Environmental Management
CHARLOTTE W6TER
4222 Westmont Drive / Charlotte, NC 28217
P: 704-336-4581 / C: 704-634-6984 / charlottewater.org
From: Coco, Nick A <[e-mail]>
Sent: Friday, January 13, 2023 1:50 PM
To: Sypolt, Shannon<[e-mail]>
Cc: Montebello, Michael J <[e-mail]>
Subject: [EXT]RE: [External] RE: [EXT]Additional Information Request: NCO024970 McAlpine Creek NPDES Permit
Application
Hi Shannon,
I hope all is well.
I'm making good progress on the 3 renewals for McAlpine Creek WWMF, Irwin Creek WWTP and Sugar Creek WWTP. I
was hoping you could just provide me with the monitoring frequency reduction request and criteria check for the Irwin
and Sugar Creek plants. I also wanted to clarify the chemical addendum. We will need the addendum for each of these
facilities. I know that you had mentioned that the addendum was not necessary since no additional monitoring had been
conducted, but we will need that written on the chemical addendum form and signed (anywhere on the form will do). If
no additional sampling was conducted, you can just note that no additional sampling was conducted and therefore no
additional parameters were identified.

One last question I have is related to 1,4-dioxane. Has Charlotte Water conducted any monitoring of 1,4-dioxane at
these 3 plants? It appears that each facility has at least one industry type linked to use of 1,4-dioxane in their
pretreatment programs.
Thanks in advance for your time and help on this,
Nick Coco, PE (he/him/his)
Engineer 111
NPDES Municipal Permitting Unit
NC DEQ / Division of Water Resources / Water Quality Permitting
Office: [phone]
[e-mail]
"Email is preferred but 1 am available to talk by via Microsoft Teams"
Physical Address: 512 North Salisbury St.,Raleigh, NC, 27604
Mailing Address: 1617 Mail Service Center, Raleigh, NC, 27699-1617
D— E
NORTH CAROLINA7d� Q
ki;
Department of Environmental Quality
Email correspondence to and from this address is subject to the North
Carolina Public Records Law and may be disclosed to third parties.
From: Sypolt, Shannon<[e-mail]>
Sent: Tuesday, October 4, 2022 10:00 AM
To: Coco, Nick A <[e-mail]>
Cc: Macomber, Maggie <[e-mail]>; Lockler, Joseph <[e-mail]>;
Montebello, Michael J<[e-mail]>; Jarrell, Jackie <[e-mail]>; Smith, Reid
<[e-mail]>
Subject: [External] RE: [EXT]Additional Information Request: NCO024970 McAlpine Creek NPDES Permit Application
CAUTION: External email. Do not click links or open attachments unless you verify. Send all suspicious email as an attachment to
Report Spam.
Good morning Nick,
Please see the following responses, and their associated attached documents, for the information that you have
requested in your email below:
1. Please see the five attached PPA's that were completed since McAlpine's last permit renewal. Although
McAlpine's permit only required three PPA's be performed during the last permit cycle, CLTWater conducts
PPA's annually at all of our facilities.
2. Our biosolids permit number is WQ0000057.
3. The estimated average daily volume of I&I is 4.176 MGD.
4. McAlpine WWMF would like to continue reduced monitoring frequencies (2x/week) for conventional
parameters. Please see the attached spreadsheet that demonstrates McAlpine WWMF has met all the
requirements for reduced monitoring frequencies as an "Exceptionally Performing Facility".

To the best of our knowledge, all samples collected at McAlpine WWMF that are covered under a method listed
in 40 CFR Part 136 and run by a state certified lab, have been reported to NCDWR on our monthly DMR's. No
additional pollutants with methods listed in 40 CFR Part 136 have been analyzed, therefore, the Chemical
Addendum form was not submitted in our application.
Per your request, please see the attached CLTWater Mercury Minimization Plan.
The treatment unit components list submitted in our permit application is accurate and represents all
permanent treatment units currently present at McAlpine.
If you have any questions concerning the information contained in this email, or if you need any additional information,
please feel free to contact me directly. Thank you for your assistance with the renewal of McAlpine's NPDES permit.
Respectfully,
Shannon Sypolt
Water Quality Program Administrator
Environmental Management
CHARLOTTE Wti ,TER
4222 Westmont Drive / Charlotte, NC 28217
P: 704-336-4581 / C: 704-634-6984 / charlottewater.org
From: Coco, Nick A <[e-mail]>
Sent: Tuesday, September 13, 2022 11:47 AM
To: [e-mail]
Cc: Jarrell, Jackie <[e-mail]>; Montebello, Michael J <[e-mail]>
Subject: [EXT]Additional Information Request: NC0024970 McAlpine Creek NPDES Permit Application
Hi Kim,
I hope all is well on your end.
I have begun reviewing the NPDES renewal application for NC0024970 McAlpine Creek WWTP and have the following
comments:
1. Please provide the 3 effluent pollutant scans taken during this permit period.
2. Please provide the permit number associated with Charlotte Water's sludge disposal agreement with Synagro.
3. Please provide the estimated average daily volume of I&I. It appears this wasn't noted on the attachment or in
the application.
4. Charlotte Water was granted 2/week monitoring for BOD, ammonia, TSS and fecal coliform based on 2012 DWR
Guidance Regarding the Reduction of Monitoring Frequencies in NPDES Permits for Exceptionally Performing
Facilities. The renewal application does not include a request for continuation of this monitoring frequency
reduction. If this is a mistake, and Charlotte Water would like to continue 2/week monitoring for these
parameters, please submit a request to continue this requirement and include confirmation of the approval
criteria outlined in the attached guidance document.
5. As required by Session Law 2018-5, Senate Bill 99, Section 13.1(r), every applicant shall now submit
documentation of any additional pollutants for which there are certified methods with the permit application if
their discharge is anticipated. The list of pollutants may be found in 40 CFR Part 136, which is incorporated by
reference. If there are additional pollutants with certified methods to be reported, please submit the Chemical
Addendum to NPDES Application table with your application and, if applicable, list the selected certified
analytical method used. If there are no additional pollutants to report, this form is not required to be included
with your application. This requirement applies to all NPDES facilities. The Chemical Addendum to NPDES

Application will be required for any type of facility with an NPDES permit, depending on whether those types of
pollutants are found in your wastewater. Please fill out, sign and submit the Chemical Addendum to NPDES
Application.
Please provide a copy of the Mercury Minimization Plan prepared for this facility, per Special Condition A.(10) of
the current permit.
Please verify the accuracy of this component list for the McAlpine Creek WWTP:
+ FIow egu4izatiq
�cr�xuing
+ �sr''it ts�noval
i F'nrrl3r}C�tlflt#CJ'k
• �L2YTit�4q l��tf1�
BiolPgical and chamical phouphorus rcmcavil
■ Alkidino iWiliva for nitriPi"fion
■ Chlu�inutiun
Dochlorinaiion
+ Anaerobic sludgc digestion
+ Contrngm and gravitysludgc ihi,rLcnk4r
+ Rand mind filtem
Thank you in advance for all of your help with this. If you have any questions for me along the way, please do not
hesitate to reach out.
Best,
Nick Coco, PE (he/him/his)
Engineer H/
NPDES Municipal Permitting Unit
NC DEQ / Division of Water Resources / Water Quality Permitting
Office: [phone]
[e-mail]
"Email is preferred but 1 am available to talk by via Microsoft Teams"
Physical Address: 512 North Salisbury St.,Raleigh, NC, 27604
Mailing Address: 1617 Mail Service Center, Raleigh, NC, 27699-1617
kl;NORTH CAROLINA
Department of Environmental Quality
Email correspondence to and from this address is subject to the North
Carolina Public Records Law and may be disclosed to third parties.

CHARLOTTE
W44TER
July 5, 2017
Ms. Jennifer Busam (via Federal Express and electronic mail)
NCDEQ — Division of Water Resources
1612 Mail Service Center
Raleigh, NC 27699-1612
Subject: Charlotte Water Comments on Draft NPDES Permit for Irwin Creek WWTP
(NC0024945); Mecklenburg County, NC
Ms. Busam:
In a letter dated May 31, 2017 (and received via email on June 6, 2017), the North Carolina Department
of Environmental Quality — Division of Water Resources ("DWR") provided Charlotte Water ("CLTWater")
with a draft permit for the Irwin Creek Wastewater Treatment Plant, NCO024945 ("Draft Permit"). This
facility is located in Mecklenburg County, North Carolina, and is owned and operated by CLTWater, a
department of the City of Charlotte. The purpose of this letter is to provide comments on this Draft
Permit. CLTWater is providing the following comments for your consideration in the final permit:
Part I A 0) Chromium VI Monthly Average Limit Daily Maximum Limit and Monthly Monitoring
Requirement
CLTWater requests that the limits and the monthly monitoring requirement for chromium VI be removed
from the permit. In support of this request, we are providing additional information regarding a chromium
contributor in the Irwin Creek WWTP basin and additional sampling data.
Significant Industrial User (SIU) Information
The Irwin Creek WWTP had an SIU that was a significant chromium contributor. This SIU has had
chromium -related compliance problems dating back for several years. The SIU ceased all industrial
discharges on 09/30/16, and currently maintains a Zero Discharge Certification with CLTWater. However,
during close-out operations in September 2016, industrial self -monitoring resulted in two slug loads of
total chromium (Sept. 23' and 27t). The SIU was issued an NOV with a civil penalty in late 2016, which
was subsequently paid on December 2, 2016.
Additional Data
CLTWater is requesting that DWR give consideration to our most recent total chromium data since the
data used in the Reasonable Potential Analysis ("RPA') for this draft permit is no longer representative of
current conditions. The majority of this data represents the time period after the aforementioned SIU
ceased industrial discharge and is more representative of current operating conditions. Table 1 contains
our most recent 58 sample results that we would like considered in a new RPA. This data set represents
a timeframe from 08/04/16 through 06/26/17 (approximately 11 months).
Charlotte Water 5100 Brookshire Blvd, Charlotte, NC 29216 charlottevrater.org
operated by the City of Charlotte

Table 1— Effluent Total Chromium Results for Irwin WWTP C0024945 as reported on eDMRs
Date
Results
Mpg/�)
Date
Results
(pg/E)
Date
( jig/E)(pg/L)
Resultsr5/24/2017
Results
8/17/2016
< 5
12/2/2016
< 5
2/28/2017
< 5
< 5
8/23/2016
< 5
12/7/2016
< 5
3/6/2017
< 5
5/25/2017
< 5
8/31 /2016
< 5
12/14/2016
< 5
3/15/2017
< 5
5/31 /2017
< 5
9/7/2016
< 5
12/21/2016
5.2
3/22/2017
< 5
6/1/2017
< 5
9/13/2016
< 5
12/28/2016
1 /4/2017
< 5
< 5
3/29/2017
4/4/2017
< 5
< 5
6/8/2017
6/9/2017
< 5
< 5
9/21 /2016
< 5
9/28/2016
< 5
1/7/2017
< 5
4/12/2017
< 5
6/14/2017
< 5
10/5/2016
< 5
1/11/2017
< 5
4/19/2017
< 5
6/15/2017
< 5
10/12/2016
< 5
1/18/2017
< 5
4/26/2017
< 5
6/22/2017
< 5
10/19/2016
< 5
1/25/2017
< 5
5/3/2017
< 5
6/23/2017
< 5
10/26/2016
< 5
2/1 /2017
< 5
5/4/2017
< 5
6/24/2017
< 5
11/3/2016
< 5
2/5/2017
< 5
5/9/2017
< 5
6/25/2017
< 5
11/9/2016
< 5
2/8/2017
< 5
5/10/2017
< 5
6/26/2017
< 5
11/16/2016
< 5
2/15/2017
< 5
5/17/2017
< 5
11/23/2016
< 5
2/22/2017
< 5
5/18/2017
< 5
CLTWater is also providing additional data collected by CH2M Hill (Table 2) during a recent evaluation of
the Irwin Creek WWTP to support the removal of this limit and monitoring requirement. This study was
commissioned by CLTWater in order to provide additional information regarding potential hardness and
metals impacts during the NPDES permit renewal process. Most of this information (excluding a single
data point for May 2017) was presented to DWR staff during an onsite meeting at the Irwin Creek WWTP
on May 5, 2017. It was also provided electronically to Ms. Busam on May 11, 2017. This data was
initially collected on a weekly basis for 12 weeks, and is now being collected monthly in order to maintain
the data set. These samples were collected in accordance with EPA Method 1669 for the purposes of
analyzing both dissolved and total recoverable metals, and as such were `grab' samples; they do not
appear on Irwin Creek WWTP eDMRs since they were not collected as 24-hour composite samples. All
of these additional total chromium samples have yielded results that are less than detectable levels.
CLTWater is providing the additional data in Table 2 to further support our request to remove the limits
and the monitoring requirement for Chromium VI.
Charlotte Water 5100 Brookshire Blvd, Charlotte, NC 28216 charlottewater.org
1 Operated by the City of Charlotte

Table 2 — Effluent Total Chromium for Irwin WWTP (NC0024945) as reported in Special Study
(Please note that the data below is not reported to DWR via the eDMR system since it is collected as a grab sample)
Date
Results
/L)
Date
Results
�p /L
Date
Results
IL)
Date
Res It
1 /17/2017
<5
2/14/2017
<5
3/16/2017
<5
5/16/2017
<5
1 /25/2017
<5
2/21 /2017
<5
3/21 /2017
<5
2/1 /2017
<5
3/1/2017
<5
3/30/2017
<5
2/7/2017
<5
3/7/2017
<5
4/11/2017
<5
CLTWater is requesting that DWR provide any signed and/or approved copy of any implementation
procedures or policies that DWR utilizes when determining chromium VI limits and/or monitoring
requirements. We seek to fully understand the process that led to DWR's decision to establish limits in
this permit. It is unclear to CLTWater how limits were established in this situation given the absence of
any chromium VI data. It is CLTWater's understanding that reasonable potential was established and a
limit was determined based on a single Total Chromium result of 51 lag/L. The only other recent value
used in the RPA above the detection limit was a result of 5.2 tag/L. We do not believe it is reasonable to
establish a limit and/or monitoring requirements for chromium VI based solely on total chromium data;
especially based on the background information presented for the Irwin Creek WWTP discussed above.
We appreciate NCDWR's consideration of this more recent data and request an updated RPA be used for
the permit.
Part 1. A.0) Cvanide Monthly Average Limit Daily Maximum Limit and Monthly Monitorin
CLTWater is requesting an increased monitoring requirement for cyanide in lieu of the proposed monthly
average and daily maximum limits. Monitoring for cyanide twice monthly would increase the data set for
this parameter and would support future permitting decisions. The decision to implement these limits is
based on a single sample result of 17 tag/L from nearly 3 years ago. All other results were less than the
detection limit. We believe that additional data would lead to a more accurate wastestream
characterization and better decision -making for future permitting purposes.
CLTWater is requesting that DWR provide any signed and/or approved copy of any implementation
procedures or policies that DWR utilizes when determining cyanide limits and/or monitoring requirements.
We seek to fully understand the process that led to DWR's decision to establish limits for cyanide in this
permit.
Part I. A.0) Footnote 8 Effluent Hardness Samples shall coincide with sampling of metals
CLTWater is requesting that this requirement and its corresponding Footnote 8 be removed from our final
permit. CLTWater routinely samples hardness and metals at a frequency greater than quarterly, usually
weekly for metals and monthly for hardness. We would like to continue our current sampling protocols
and maintain the ability to obtain additional hardness and metals samples independently of one another.
This request is based on our concern about the possible third party interpretation of this requirement as it
is currently written. It could be perceived as a monitoring violation if one of these parameters is sampled
without the other when additional sampling is performed.
Charlotte Water 5100 Brookshire Blvd, Charlotte, NC 28216 chariottewater.org
M operated by the City of Charlotte

CLTWater does not understand the technical rational or the statutory basis for the requirement to sample
hardness at the same time as metals. It is our understanding that NCDWR uses average hardness and
metals results from the facility data to determine metals limits. Since only the average hardness and
metals values are used to determine metals limits then the requirement to sample hardness in
conjunction with metals is unnecessary and creates additional opportunity for reporting violations to
occur. Without technical or statutory justification(s) this requirement should be removed from the permit.
Part I. A.0) Footnote Section — Unnumbered Statement that Addresses Solids Discharge
The statement "THERE SHALL BE NO DISCHARGE OF FLOATING SOLIDS OR VISIBLE FOAM IN
OTHER THAN TRACE AMOUNTS" is a new addition to this permit. This statement is more stringent and
subjective in its use of "trace amounts" phrasing than the language used in the Water Quality Standards
for Class C Waters (15A NCAC 02B .0211 (8)). Although CLTWater seeks to always achieve the highest
level of treatment possible with the technologies it currently has available, extenuating circumstance
occasionally occur. This request is based on our concern about the possible third party interpretation of
this requirement as it is currently written since "trace amounts" is not clearly defined in the permit. The
Water Quality Standard is more appropriate and objective with regard to regulating this wastewater
discharge characteristic when it establishes that "Floating solids ... shall not make the water unsafe or
unsuitable for aquatic life and wildlife or impair the waters for any designated uses." CLTWater
respectfully requests that the more stringent narrative limit be removed from this permit.
Charlotte Water appreciates your consideration of our requests and comments. If you have any
questions or require further information concerning this letter please feel free to contact Shannon Sypolt,
Water Quality Program Administrator, at [phone] or me at [phone].
Respectfully,
0acqeline A. Jar II, P.E.
Operations Chief, Environmental Management Division
CC:
Shannon Sypolt, CLTWater
Mike Lingerfelt, CLTWater
Charlotte Water 5100 Brookshire Blvd, Charlotte, NC 28216 r_liarlottewater.org
„ operated by the City of Charlotte

Coco, Nick A
From: Cantrell, Wade <[e-mail]>
Sent: Wednesday, April 5, 2023 12:47 PM
To: Coco, Nick A
Cc: Green, Brenda A.; Waldner, Susan; Montebello, Michael J; Varlik, Banu; Behm, Pamela
Subject: Re: [External] Re: E. coli in NC permits
Follow Up Flag: Follow up
Flag Status: Flagged
CAUTION: External email. Do not click links or open attachments unless you verify. Send all suspicious email as an attachment to
Report Spam.
Nick -
Thanks for the opportunity to provide feedback. After reviewing permit limits, the NC TMDL and the actual
effluent data (summarized in the tables below), we do not object to the draft limits for the 3 NC facilities
based on fecal coliform bacteria as the indicator. This conclusion is based on (1) the general consistency of of
SC and NC permit limits which account for the relationship between fecal coliform and E coli as determined in
the DHEC Pathogen Indicator Study circa 2009 and (2) the extensive effluent data record showing a de
minimus number of samples greater than 400 fecal coliform.
It is possible that new information or comments arising during development of the SC E coli TMDL could cause
another look, but based on what we know now, we do not believe any changes to proposed bacteria limits are
necessary at this time.
Thanks!
Wade
i

Limits Comparison
Measure
Previous SC FC
S.andardfPermits
Current SC E. coli
Standard/Permits
Current NC
Permi.s
Current NC
T IDL
Monthly Average or GM
2-00
126
200
Weekly Average
400
Daily Max
4-00
349*
1000
Not to Exceed"
4-00
So0*
100C
1vt
*one sample>349 is not a violation if (1) the sample did not exceed 800AND
(2) 2 additional samples wvithi n 48 hours do not exceed 349
"Appears TMDL used dynamic model with adjusted time series for continuous point sources
with maximum concentration adjusted down to 1000, but not su re.
Effluent D MR Data Summary
Effluent DM R Summary of Fecal Coliform
NC Permit # POR
NCO0 4937 11412000 - 1 /30/ 022
NCO0 4970 11512000 - 1 /30/ 022
NCO0 4945 11412000 - 1 /30/ 022
Effluent DM Summary of Fecal Coliform
NC Permit#
POR
NCO0 4937
1111201 - 1 /30/ 022
NCO0 4970
1121201 - 1 /30/ 022
NCO0 4945
1121201 - 1 /30/ 022
n
n >400
% >400
Marc
5674
94
1.70%
15000
5695
56
0.9 %
40000
5505
69
1. 5%
6500
n
n >400
% >400
Marc
498
3
0.1 %
710
2498
5
0. 0%
891
2495
2
0.0 %
6000
Wade Cantrell
303d, Modeling & TMDL Section Manager
Division of Water Quality - Bureau of Water
S.C. Dept. of Health & Environmental Control
Office: [phone]
Connect: www.scdhec.gov Facebook Twitter
0
From: Coco, Nick A <[e-mail]>
Sent: Tuesday, March 14, 2023 1:12 PM
To: Cantrell, Wade <[e-mail]>
Cc: Green, Brenda A. <[e-mail]>; Waldner, Susan <[e-mail]>; Montebello, Michael J
<[e-mail]>
Subject: RE: [External] Re: E. coli in NC permits
ra

*** Caution. This is an EXTERNAL email. DO NOT open attachments or click links from unknown senders or unexpected email.
***
Hi Wade,
Sorry — took a second to dig it up. The attached should be the FC TMDL. These 3 are already drafted, and one of the
internal review comments was to check with you regarding e. coli, so I'd say a response as soon as is reasonable on your
end, considering your own workloads and responsibilities. Is end of March too soon?
Thanks,
Nick Coco, PE (he/him/his)
Engineer 111
NPDES Municipal Permitting Unit
NC DEQ / Division of Water Resources / Water Quality Permitting
Office: [phone]
[e-mail]
"Email is preferred but 1 am available to talk by via Microsoft Teams"
Physical Address: 512 North Salisbury St.,Raleigh, NC, 27604
Mailing Address: 1617 Mail Service Center, Raleigh, NC, 27699-1617
NORTH CAROLINA Q1V
Department of Environmental Quality
Email correspondence to and from this address is subject to the North
Carolina Public Records Law and may be disclosed to third parties.
From: Cantrell, Wade <[e-mail]>
Sent: Tuesday, March 14, 2023 12:21 PM
To: Coco, Nick A <[e-mail]>
Cc: Green, Brenda A. <[e-mail]>; Waldner, Susan <[e-mail]>; Montebello, Michael J
<[e-mail]>
Subject: Re: [External] Re: E. coli in NC permits
CAUTION: External email. Do not click links or open attachments unless you verify. Send all suspicious email as an attachment to
Report Spam.
Great, thanks Nick. Last thing, just if you have a link to NC FC TMDL would be helpful, if not we might already
have it or can dig around.
We are ramping up an E. coli TMDL for our side of Sugar Creek and good to think about these questions
now. I'd like for our TMDL project manager to take a look. When do you need response?
Wade Cantrell
303d, Modeling & TMDL Section Manager
Division of Water Quality - Bureau of Water
S.C. Dept. of Health & Environmental Control

Office: [phone]
Connect: www.scdhec. ov Facebook Twitter
From: Coco, Nick A <[e-mail]>
Sent: Tuesday, March 14, 2023 12:11 PM
To: Cantrell, Wade <[e-mail]>
Cc: Green, Brenda A. <[e-mail]>; Waldner, Susan <[e-mail]>; Montebello, Michael J
<[e-mail]>
Subject: RE: [External] Re: E. coli in NC permits
*** Caution. This is an EXTERNAL email. DO NOT open attachments or click links from unknown senders or unexpected email.
***
Hi Wade,
Please see attached for the data requested. I've included effluent and instream data (for fecal — maintained in the
McAlpine Creek DMR for all sites) for NCO024970 McAlpine Creek WWMF, NCO024945 Irwin Creek WWTP and
NCO024937 Sugar Creek WWTP. While the McAlpine Creek WWMF is the permit in question, each of the three facilities
are owned and operated by Charlotte Water, are currently in the renewal drafting process and discharge just above the
state border in about the same area. I figured offering more info couldn't hurt. Feel free to ignore extraneous info.
Please let me know if there is anything else you need.
Thanks again for looking into this,
Nick Coco, PE (he/him/his)
Engineer 111
NPDES Municipal Permitting Unit
NC DEQ / Division of Water Resources / Water Quality Permitting
Office: [phone]
[e-mail]
"Email is preferred but 1 am available to talk by via Microsoft Teams"
Physical Address: 512 North Salisbury St.,Raleigh, NC, 27604
Mailing Address: 1617 Mail Service Center, Raleigh, NC, 27699-1617
e: D E "A
NORTH CAROLINA cl;
Department of Environmental Quality
Email correspondence to and from this address is subject to the North
Carolina Public Records Law and may be disclosed to third parties.
From: Cantrell, Wade <[e-mail]>
Sent: Tuesday, March 14, 2023 11:50 AM
To: Coco, Nick A <[e-mail]>

Cc: Green, Brenda A. <[e-mail]>; Waldner, Susan <[e-mail]>
Subject: [External] Re: E. coli in NC permits
CAUTION: External email. Do not click links or open attachments unless you verify. Send all suspicious email as an attachment to
Report Spam.
Hi Nick -
Brenda asked us (303d/TMDL/WLA section) to look at your question below. Thanks for reaching out. Would it
be possible to get DMR data for this facility, say flow and bacteria going back to 2000 or as available in your
database? Also, do you have a link for the NC FC TMDL? Would like to check a couple of things and give
feedback asap.
Thanks,
Wade
Wade Cantrell
303d, Modeling & TMDL Section Manager
Division of Water Quality - Bureau of Water
S.C. Dept. of Health & Environmental Control
Office: [phone]
Connect: www.scdhec. ov Facebook Twitter
From: Green, Brenda A. <[e-mail]>
Sent: Monday, March 13, 2023 1:46 PM
To: Cantrell, Wade <[e-mail]>
Subject: Fwd: E. coli in NC permits
Will you take a look at the original question from NC and give me any feedback? Thanks!
Get Outlook for iOS
From: Siddiqui, Mohammed <[e-mail]>
Sent: Thursday, March 9, 2023 12:14:29 PM
To: Green, Brenda A. <[e-mail]>; Clarke, Shawn <[e-mail]>
Subject: Re: E. coli in NC permits
McAlpine creek south of the border is impaired
Use: AL/Rec
Cause: Bio/Ecoli
Also there is a d/s intake S29106
and a little further down is S 12101
Sohail Siddiqui, P.E.
Environmental Engineer, Domestic Wastewater Permitting Section, Bureau of Water
S.C. Dept. of Health & Environmental Control
Office: [phone]
Fax: [phone]
Connect: www.scdhec.gov Facebook Twitter

J
From: Green, Brenda A. <[e-mail]>
Sent: Thursday, March 9, 2023 10:43 AM
To: Clarke, Shawn <[e-mail]>
Cc: Siddiqui, Mohammed <[e-mail]>
Subject: Fw: E. coli in NC permits
This is one I didn't see. I think we would want e.Coli limits since they are close.
Brenda Green
Manager, Domestic Wastewater Permitting Section
Bureau of Water
S.C. Dept. of Health & Environmental Control
Office: [phone]
Fax: [phone]
Connect: www.scdhec. ov Facebook Twitter
From: Coco, Nick A <[e-mail]>
Sent: Wednesday, March 1, 2023 2:19 PM
To: Green, Brenda A. <[e-mail]>
Cc: Montebello, Michael J <[e-mail]>
Subject: RE: E. coli in NC permits
*** Caution. This is an EXTERNAL email. DO NOT open attachments or click links from unknown senders or unexpected email.
***
Hi Brenda,
I was wondering if you were able to give this email some thought. I'll be sending you a copy of the draft permit as well
once it makes it to that stage, but wanted to make sure I addressed this particular item before sending it out for
comment.
Thanks,
Nick Coco, PE (he/him/his)
Engineer 111
NPDES Municipal Permitting Unit
NC DEQ / Division of Water Resources / Water Quality Permitting
Office: [phone]
[e-mail]
"Email is preferred but 1 am available to talk by via Microsoft Teams"
Physical Address: 512 North Salisbury St.,Raleigh, NC, 27604
Mailing Address: 1617 Mail Service Center, Raleigh, NC, 27699-1617

0 i;:; A
�
tc���D- E-
NORTH CAROLINA7d� Q
kJ/)
Department of Environmental Quality
Email correspondence to and from this address is subject to the North
Carolina Public Records Law and may be disclosed to third parties.
From: Coco, Nick A
Sent: Wednesday, February 22, 2023 9:58 AM
To: Green, Brenda A. <[e-mail]>
Cc: Montebello, Michael J <[e-mail]>
Subject: E. coli in NC permits
Hi Brenda,
I hope you're doing well.
I'm currently working through the renewal of the McAlpine Creek WWMF NPDES permit NC0024970. This is a major
discharger (64.0 MGD permitted flow) which discharges above the NC/SC border. As you may know, this particular
facility is subject to a fecal coliform TMDL, which requires the facility to meet a daily maximum limitation of 1000/100mL
in addition to the standard MA of 200/100mL and WA of 400/100mL. In the peer review process, it was brought to my
attention that SC has E.coli standards to uphold as well and it was suggested I reach out to you to either ensure that the
fecal coliform TMDL is protective of the SC water uses or ask what type of E.coli considerations should be made for this
discharge. Would you be able to share some insight here?
Thanks so much in advance for your time and any guidance you can provide.
Best,
Nick Coco, PE (he/him/his)
Engineer 111
NPDES Municipal Permitting Unit
NC DEQ / Division of Water Resources / Water Quality Permitting
Office: [phone]
[e-mail]
"Email is preferred but 1 am available to talk by via Microsoft Teams"
Physical Address: 512 North Salisbury St.,Raleigh, NC, 27604
Mailing Address: 1617 Mail Service Center, Raleigh, NC, 27699-1617

0 i;:; A
�
tc���D- E-
NORTH CAROLINA7d� Q
kJ/)
Department of Environmental Quality
Email correspondence to and from this address is subject to the North
Carolina Public Records Law and may be disclosed to third parties.

From: Miller, Shirley
To: baintert61charlottenc.aov
Cc: Hamilton, Renee; Kaldani. Jason (he/him/his); Peter. Shields(&icf.com; Chin. Kai; Butler, Ron; Carioti, Joe;
IN Ledesma, Michael; Pickell, Casey; Mitchell, Greg; Jacobson, David; sarah.daley(cicharlottenc.aov; Phillips, David;
Dollar, Carla (she/her/hers); Mcgee. Keyes; Montebello, Michael J
Subject: [External] CONFIRMING CROMERR COMPLIANCE: Status of Charlotte Water, SwiftComply Application
Date Tuesday, September 12, 2023 10:47:17 AM
CAUTION: External email. Do not click links or open attachments unless verified. Report suspicious emails with the
Report Message button located on your Outlook menu bar on the Home tab.
Dear Bill Gintert,
The CROMERR program confirms that the Charlotte Water SwiftComply system is
CROMERR compliant. Per the process EPA Office of Information Management (OIM)
agreed to with EPA Office of Water, it's up to the state or EPA Regional
pretreatment coordinators (in your case the State of North Carolina) to take
whatever final action they see fit in acting upon your program modification request
as well as confirming compliance with separate 40 CFR 403 electronic reporting
requirements. That process can be found here:
https: / /www.epa.gov/cromerr/cromerr-compliance-publicly-owned-treatment-
works-pretreatment-program
Under this process, the CROMERR program informally provides technical assistance
and advice to the state or EPA Regional pretreatment coordinators of CROMERR
compliance - because there is no way they could easily perform this task. However,
there is no official action taken by CROMERR to modify the program (which is really
what we do when we approve a CROMERR application). That is left to the state or
EPA Regional pretreatment coordinator to take action however they see fit, and
presumably in a manner that they typically would take action on other
pretreatment program modification requests.
The CROMERR program's part of this process is complete and has confirmed your
approach as CROMERR compliant. The final action and any further review in terms
of 403 e-reporting requirements will be taken by the State of North Carolina. Once
we have communicated our assessment of compliance, we certainly also appreciate
an FYI from Charlotte Water, the state or EPA Region that the action has been
taken - but we are not coordinating this part of the process as it is technically not a
CROMERR approval action.
Based on the CROMERR application you submitted, you will be using Shared
CROMERR Services (SCS) with no modifications. This means that Charlotte Water
will use SCS with all pre-set defaults. Any changes to this could impact CROMERR
compliance. Therefore, this approval is conditional on Charlotte Water's use of SCS
with no modifications. If Charlotte Water changes anything as it implements the
system, please notify the EPA CROMERR Team of the changes. EPA will review any
changes for CROMERR compliance and work with Charlotte Water if any CROMERR
compliance issues are identified.
I have copied EPA's Office of Water, EPA Region 4, and North Carolina Department
of Environmental Quality (NCDEQ). I believe NCDEQ will take the official action on
your request. The means of official action on the program modification request is
entirely at the discretion of NCDEQ.

Please let us know if you have any questions. Thank you for your support in
implementing CROMERR!
Regards,
The EPA CROMERR Team
cromerrPepa.gov
eoS71MF
Shirley M. Miller (She/her/hers)
s.
�Z
CROMERR Program Manager
Office of Information Management
AP
Phone [phone]
Email [e-mail]
1200 Pennsylvania Avenue, NW
Washington, DC 20460
https://www.epa.gov/cromerr

DocuSign Envelope ID: 700AF170-7A79-4E57-9DD4-CD70F25D6CC0
ROY COOPER
Governor
ELIZABETH S. BISER
Secretary
RICHARD E. ROGEM, JR.
Director
NORTH CAROLINA
Environmental Quality
11/1/2023
Via Electronic Mail (bill. in�tert&charlottenc.gov)
Bill Gintert
Environmental Compliance Manager
Charlotte Water
4222 Westmont Drive
Charlotte, NC 28217
Subject: Pretreatment Program Modification to Receive Reports Electronically from Its
Industrial Users (IUs) [Cross -Media Electronic Reporting Rule (CROMERR)]
Pretreatment Program: Charlotte Water
Wastewater Treatment Plant: Irwin Creek WWTP
NPDES# NC0024945, Mecklenburg County
Dear Bill Gintert:
On 12/09/2022 the NPDES Municipal Permitting Branch of the Division of Water Resources
received Charlotte Water's notice of intent to modify the pretreatment program's legal authority
and procedures to receive reports from Industrial Users electronically (CROMERR Application).
Charlotte Water currently receives wet ink signature pretreatment reports from IUs.
On 9/12/2023 the Municipal Unit received an email from Shirley Miller of EPA's Office of
Information Management (aka, The EPA CROMERR Team), titled "CONFIRMING CROMERR
COMPLIANCE: Status of Charlotte Water, SwiftComply Application." This email indicates "The
CROMERR program confirms that the Charlotte Water SwiftComply system is CROMERR
compliant," and "The means of official action on the program modification request is entirely at
the discretion of NCDEQ."
Division review of the complete application package indicates conformity with the PART 3 -
CROSS -MEDIA ELECTRONIC REPORTING (Code of Federal Regulations - Title 40, Chapter
I, Subchapter A, Part 3).
The Division will include in the Charlotte Water Irwin Creek WWTP (NC0024945) NPDES
permit renewal public notice a courtesy announcement of modification to the Charlotte Water
Pretreatment Program for CROMERR. The Division recognizes the proposed pretreatment
program change for CROMERR to be a non -substantial modification subject to approval
procedures in 40 CFR 403.18(d), and public notice or opportunity for hearing is not required for
non -substantial modifications. Charlotte Water's pretreatment program is approved to begin
utilizing the Charlotte Water SwiftComply System to receive and send electronic reports as
required.
©� ��� North Carolina Department of Environmental Quality I Division of Wafer Resources
512 North Salisbury Street I 1611 Mail Service Center I Raleigh, North Carolina 27699-1611
NORTH CARCLINA ^�, 919.707.9000

DocuSign Envelope ID: 700AF170-7A79-4E57-9DD4-CD70F25D6CC0
Federal and State pretreatment regulations require the local delegated pretreatment program to
effectively control and document the discharge of wastewater from Significant/Categorical
Industrial Users to the POTW. It is the POTW's responsibility to ensure that these objectives are
consistently met.
If you have any questions or comments, please contact Keyes McGee at [phone] [email:
[e-mail]]. Thank you for your continued support of the Pretreatment Program.
tkm/CW_Irwin CROMERR_01
Ec: Municipal Unit File
Sarah Daley, CW IP Supervisor
Wes Bell, WSRO
Central Files (Laserfische)
Sincerely,
Do'cu,Si-gned b%y�:,� ` A
1'NVVWKni AuvA,kl h
C464531431644FE...
for Richard E. Rogers, Jr., Director
Division of Water Resources
D � � 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
NORTH CAHoi1Na 919.707.9000
n.w�m m �.—w rwaiZ\-Op�

Whole Effluent Toxicity Testing and Self Monitoring Summary
CMUD-Irwin Creek WWTP
NCO024945/001
County: Mecklenburg Region:
MRO
Basin: CTB34
Jan Apr Jul Oct
SOC JOC:
Ceri7dPF Begin:
10/1/2017 chr lim: 83%
NonComp: Single
7Q10:
4.9 PF:
15.0 IWC: 83.0
Freq: Q
J
F M
A M
J
J
A
S O
N
2019 >100(s)
- -
>100 >100(P) -
-
>100(s)
-
- >100(s)
-
2020 >100(s)
>100(s)
100 (P) >100% >100%
>100(S)>100(s)
2021 >100
>100 (s) >100 (s)
>100 (s) >100 (S)
>100 (S) >100 (s) >100 (I
2022 87.1(S) >100 (S) >100 (P)
>100 (s) >100 (s)
>100 (s) >100 (S)
>100 s >100 S
2023 >100 >100
- -
>100>100 -
-
>100 >100
-
- >100>100
-
CMUD-Mallard Cr. WWTP
NCO030210/001
County: Mecklenburg Region:
MRO
Basin:
YAD11
Feb May Aug Nov
SOC JOC:
Ceri7dPF Begin:
1/1/2014 chr lim: 90%
NonComp: ChV Avg
7Q10:
0.64 PF:
12.0 IWC: 94.0
Freq: Q
J
F M
A M
J
J
A
S O
N
2019 -
Pass(s) -
- >100(P) Pass(s)
-
-
Pass(s)
- -
Pass(s)
2020 -
Pass(s) -
- Pass(s)
-
-
Pass ChV>100%Pass
- -
Pass
2021 -
Pass -
- Pass (s) Pass (S)
-
-
Fail
>100 Pass >100(s)>100(s)
>100 (P) Pass (S) Pass (s)
2022 -
Pass >100 (P) -
- Pass (s) Pass (S)
-
-
Pass Pass
- -
Pass Pass
2023 -
Pass Pass -
- Pass Pass >100
-
-
Pass
- -
-
CMUD-McAlpine WWTP
NCO024970/001
County: Mecklenburg
Region: MRO
Basin:
CTB34
Mar Jun Sep Dec
SOC JOC:
Ceri7dPF Begin:
10/1/2017 chr lim: 90%
NonComp: Single
7Q10:
0.3
PF: 64.0
IWC:
99.35 Freq: Q
J
F M
A M
I
J
A
S
O
N
2019 -
- Pass(s)
- -
>100(P) Pass(s)
-
-
Pass(s)
-
-
2020 -
- Pass(s)
- -
Pass(s)
-
-
>100(P) Pass
-
-
2021 -
- Pass
- -
Pass(s)
-
-
Pass (S) Pass(s)
-
-
2022 -
- Pass (5) Pass (S) >100 (F - -
Pass (S) Pass (S)
-
-
Pass Pass
-
-
2023 -
- Pass Pass
- -
Pass Pass Pass
-
-
Pass Pass
-
-
CMUD-McDowell Cr. WWTP
NCO036277/001
County: Mecklenburg
Region: MRO
Basin:
CTB33
Jan Apr Jul Oct
SOC JOC:
Ceri7dPF Begin:
1/1/2014 chr lim.: 90%
NonComp: Single
7Q10:
1.80
PF: 12.0
IWC:
85 Freq: Q
J
F M
A M
J
J
A
S
O
N
2019 Pass(s)
- -
Pass(s) >100(P) -
-
Pass(s)
-
-
Pass(s)
-
2020 Pass(s)
- -
Pass(s) -
-
97.5 Pass Pass
-
-
Pass
-
2021 Pass
- -
Pass (S) Pass (S) -
-
Pass (S) Pass (S)
-
- >100 (P) Pass (S) Pass ('- -
2022 Pass (S) Pass (S) >100
(P) - -
Pass (S) Pass (S) -
-
Pass (S) Pass (S)
-
-
Pass Pass
-
2023 Pass Pass
- -
>100 Pass -
-
Pass Pass
-
-
Pass Pass
-
Coats American -Sevier Plant
NC0004243/001
County: McDowell
Region: ARO
Basin:
CTB30
Feb May Aug Nov
SOC JOC:
Ceri7dPF Begin:
12/1/2017 chr lim: 15%
NonComp: Single
7Q10:
18.0
PF: 2.0
IWC:
14.7 Freq: Q
J
F M
A M
J
J
A
S
O
N
2019 -
Pass -
- Pass
-
-
Pass
-
-
Pass
2020 -
Pass -
- Pass
-
-
Pass
-
-
Pass
2021 -
Pass -
- Pass
-
-
Pass
-
-
Pass
2022 -
Fail 5.3 (NC)
21.2 10.6 (NC)
>60
>60
Pass
-
-
Pass
2023 -
Pass -
- Pass
-
-
Pass
-
-
Pass
C
C
D
Pass(s)
Pass
Pass >100 (P)
Pass Pass
C
C
Leeend: P= Fathead minnow (Pimohales oromelas). H=No Flow (facilitv is active). s = Solit test between Certified Labs Page 23 of 114

MONITORING REPORT(MR) VIOLATIONS for:
Permit: NCO024945 MRS Betweei 1 - 2019 and 1 - 2024 Region: %
Facility Name: % Param Nam(% County: %
Major Minor: %
Report Date: 01/02/24 Page 1 of 1
Violation Category:Limit Violation Program Category:
Subbasin: % Violation Action: %
PERMIT: NCO024945 FACILITY: Charlotte Water- Irwin Creek WWTP COUNTY: Mecklenburg REGION: Mooresville
Limit Violation
MONITORING VIOLATION UNIT OF CALCULATED %
REPORT OUTFALL LOCATION PARAMETER DATE FREQUENCY MEASURE LIMIT VALUE Over VIOLATION TYPE VIOLATION ACTION
06-2019 001 Effluent Coliform, Fecal MF, MFC 06/25/19 2 X week #/100ml 1,000 6,000 500 Daily Maximum Proceed to NOV
Broth, 44.5 C Exceeded

United States Environmental Protection Agency
Form Approved.
EPA Washington, D.C. 20460
OMB No. 2040-0057
Water Compliance Inspection Report
Approval expires 8-31-98
Section A: National Data System Coding (i.e., PCS)
Transaction Code NPDES yr/mo/day Inspection Type Inspector Fac Type
1 IN 1 2 u 3 I NC0024945 I11 121 23/02/02 I17 18I D I 19 I s I 20L]
21111I I I I I I I II I I I I I I I I I I I I I I I I I I I I I I I II I I I I I r6
Inspection
Work Days Facility Self -Monitoring Evaluation Rating B1 QA ---------------------- Reserved -------------------
67
2.0 701d I 71 I„ I 72 I r., I 71 I 74 79 I I I I I I I80
L—I ty L-1 I I
Section B: Facility Data
Name and Location of Facility Inspected (For Industrial Users discharging to POTW, also include
Entry Time/Date
Permit Effective Date
POTW name and NPDES permit Number)
09:30AM 23/02/02
17/10/01
Irwin Creek WWTP
4000 Westmont Dr
Exit Time/Date
Permit Expiration Date
Charlotte NC 28217
12:30PM 23/02/02
22/05/31
Name(s) of Onsite Representative(s)/Titles(s)/Phone and Fax Number(s)
Other Facility Data
Bill Gintert/Compliance Env Manager//
Sarah Daley///
Name, Address of Responsible Official/Title/Phone and Fax Number
Contacted
Steven J Lockler,5100 Brookshire Blvd Charlotte NC 282163371//704-336-2503/
No
Section C: Areas Evaluated During Inspection (Check only those areas evaluated)
Pretreatment
Section D: Summary of Finding/Comments (Attach additional sheets of narrative and checklists as necessary)
(See attachment summary)
Name(s) and Signature(s) of Inspector(s) Agency/Office/Phone and Fax Numbers Date
Wes Bell DWR/MRO WQ/704-235-2192/
Signature of Management Q A Reviewer Agency/Office/Phone and Fax Numbers Date
EPA Form 3560-3 (Rev 9-94) Previous editions are obsolete.
Page#

NPDES yr/mo/day Inspection Type
NCO024945 I11 12I 23/02/02 117 18 1 p I
Section D: Summary of Finding/Comments (Attach additional sheets of narrative and checklists as necessary)
The POTW currently has 55 SIUs with 24 being CIUs. One CIU (IGM) was in SNC in 2022 for a
Toluene limit violation (TRC) during first half of 2022. All SIUs were sampled and inspected in 2022.
The records reviewed during the inspection were organized and well maintained. The POTW's
Industrial Pretreatment Program was being properly implemented.
Page#

Permit: NC0024945
Inspection Date: 02/02/2023
Owner -Facility: Irwin Creek WWTP
Inspection Type: Pretreatment Compliance
Yes No NA NE
Page#

United States Environmental Protection Agency
Form Approved.
EPA Washington, D.C. 20460
OMB No. 2040-0057
Water Compliance Inspection Report
Approval expires 8-31-98
Section A: National Data System Coding (i.e., PCS)
Transaction Code NPDES yr/mo/day Inspection Type Inspector Fac Type
1 IN 1 2 u 3 I NCO024945 I11 121 22/11/09 I17 18I � I 19 I s I 20L]
21111I I I I I I I II I I I I I I I I I I I I I I I I I I I I I I I II I I I I I r6
Inspection
Work Days Facility Self -Monitoring Evaluation Rating B1 QA ---------------------- Reserved -------------------
67
2.0 701d I 71 I„ I 72 I r., I 71 I 74 79 I I I I I I I80
L—I ty L-1 I I
Section B: Facility Data
Name and Location of Facility Inspected (For Industrial Users discharging to POTW, also include
Entry Time/Date
Permit Effective Date
POTW name and NPDES permit Number)
09:20AM 22/11/09
17/10/01
Irwin Creek WWTP
4000 Westmont Dr
Exit Time/Date
Permit Expiration Date
Charlotte NC 28217
01:05PM 22/11/09
22/05/31
Name(s) of Onsite Representative(s)/Titles(s)/Phone and Fax Number(s)
Other Facility Data
Jacob Wayne Bolick/ORC/704-336-2573/
Name, Address of Responsible Official/Title/Phone and Fax Number
Contacted
Angela D Charles,5100 Brookshire Blvd Charlotte NC 282163371//704-336-5911/
No
Section C: Areas Evaluated During Inspection (Check only those areas evaluated)
Permit 0 Flow Measurement Operations & Maintenar Records/Reports
Self -Monitoring Progran 0 Sludge Handling Dispo: Facility Site Review Effluent/Receiving Wate
Laboratory
Section D: Summary of Finding/Comments (Attach additional sheets of narrative and checklists as necessary)
(See attachment summary)
Name(s) and Signature(s) of Inspector(s) Agency/Office/Phone and Fax Numbers Date
Wes Bell DWR/MRO WQ/704-663-1699 Ext.2192/
Signature of Management Q A Reviewer Agency/Office/Phone and Fax Numbers Date
Andrew Pitner DWR/MRO WQ/704-663-1699 Ext.2180/
EPA Form 3560-3 (Rev 9-94) Previous editions are obsolete.
Page#

NPDES yr/mo/day Inspection Type
NC0024945 I11 12I 22/11/09 117 18 i c i
Section D: Summary of Finding/Comments (Attach additional sheets of narrative and checklists as necessary)
On -site Representatives:
The following Charlotte Water staff were in attendance during the inspection: Mr. Jacob Bolick, Mr.
Tony Sponelli, Mr. Shannon Sypolt, Mr. Doug Wise, Mr. Michael Christiansen and Ms. Muriel Steele.
Page#

Permit: NCO024945 Owner -Facility: Irwin Creek WWTP
Inspection Date: 11/09/2022 Inspection Type: Compliance Evaluation
Permit
Yes
No
NA NE
(If the present permit expires in 6 months or less). Has the permittee submitted a new
❑
❑
❑
application?
Is the facility as described in the permit?
0
❑
❑
❑
# Are there any special conditions for the permit?
M
❑
❑
❑
Is access to the plant site restricted to the general public?
0
❑
❑
❑
Is the inspector granted access to all areas for inspection?
0
❑
❑
❑
Comment: The Division received Charlotte Water's permit renewal documentation on 12/1/2021.
Charlotte Water implements a Division approved Industrial Pretreatment Program.
The last compliance evaluation inspection at this facility was performed by DWR staff
on 10/27/2020.
Record Keeping
Are records kept and maintained as required by the permit?
Is all required information readily available, complete and current?
Are all records maintained for 3 years (lab. reg. required 5 years)?
Are analytical results consistent with data reported on DMRs?
Is the chain -of -custody complete?
Dates, times and location of sampling
Name of individual performing the sampling
Results of analysis and calibration
Dates of analysis
Name of person performing analyses
Transported COCs
Are DMRs complete: do they include all permit parameters?
Has the facility submitted its annual compliance report to users and DWQ?
(If the facility is = or > 5 MGD permitted flow) Do they operate 24/7 with a certified
operator on each shift?
Is the ORC visitation log available and current?
Is the ORC certified at grade equal to or higher than the facility classification?
Is the backup operator certified at one grade less or greater than the facility
classification?
Is a copy of the current NPDES permit available on site?
Facility has copy of previous year's Annual Report on file for review?
Yes No NA NE
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Page# 3

Permit: NCO024945
Inspection Date: 11/09/2022
Owner -Facility: Irwin Creek WWTP
Inspection Type: Compliance Evaluation
Record Keeping Yes No NA NE
Comment: The records reviewed durinq the inspection were organized and well maintained.
Discharge Monitoring Reports (eDMRs) were reviewed from October 2021 through
September 2022. No limit and/or monitoring violations were noted during the review
period.
Laboratory
Yes
No
NA
NE
Are field parameters performed by certified personnel or laboratory?
0
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Are all other parameters(excluding field parameters) performed by a certified lab?
0
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# Is the facility using a contract lab?
0
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# Is proper temperature set for sample storage (kept at less than or equal to 6.0
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■
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degrees Celsius)?
Incubator (Fecal Coliform) set to 44.5 degrees Celsius+/- 0.2 degrees?
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Incubator (BOD) set to 20.0 degrees Celsius +/- 1.0 degrees?
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Comment: Influent and effluent analyses are performed by Charlotte Water Environmental
Services Laboratory (Certification #192). ETT Environmental and ETS have been
contracted to perform effluent chronic toxicity tests.
Influent Sampling
# Is composite sampling flow proportional?
Is sample collected above side streams?
Is proper volume collected?
Is the tubing clean?
# Is proper temperature set for sample storage (kept at less than or equal to 6.0
degrees Celsius)?
Is sampling performed according to the permit?
Yes No NA NE
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Comment: The subject permit requires influent BOD and TSS composite samples. The composite
samplers are calibrated weekly and checked (for proper operation) every shift.
Effluent Sampling
Yes
No
NA
NE
Is composite sampling flow proportional?
0
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Is sample collected below all treatment units?
0
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Is proper volume collected?
0
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Is the tubing clean?
0
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# Is proper temperature set for sample storage (kept at less than or equal to 6.0
0
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degrees Celsius)?
Is the facility sampling performed as required by the permit (frequency, sampling type
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representative)?
Page# 4

Permit: NCO024945
Inspection Date: 11/09/2022
Effluent Sampling
Owner -Facility: Irwin Creek WWTP
Inspection Type: Compliance Evaluation
Yes No NA NE
Comment: The subject permit requires composite and grab effluent samples. The composite
samplers are calibrated weekly and checked (for proper operation) every shift.
Operations & Maintenance
Is the plant generally clean with acceptable housekeeping?
Does the facility analyze process control parameters, for ex: MLSS, MCRT, Settleable
Solids, pH, DO, Sludge Judge, and other that are applicable?
Comment: The wastewater treatment facility appeared to be properly operated and well
Yes No NA NE
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maintained. Facility staff incorporate a comprehensive process control program with all
measurements being properly documented and maintained on -site. In-depth
operation and maintenance records are also maintained on -site. Approximately nine
(9) SCADA stations are located throughout the treatment plant site.
The facility's SCADA system was operational and in service.
Equalization Basins
Is the basin aerated?
Is the basin free of bypass lines or structures to the natural environment?
Is the basin free of excessive grease?
Are all pumps present?
Are all pumps operable?
Are float controls operable?
Are audible and visual alarms operable?
# Is basin size/volume adequate?
Yes
No
NA
NE
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Comment: The facility is equipped with a 30 MG equalization basin (10 MG cell and a 20 MG cell).
The equalization basin is connected to the on -site SCADA system. The facility also has
the capability of diverting influent flows to the Charlotte Water/McAlpine Creek WWTP
for final treatment/disposal.
Bar Screens
Yes
No
NA NE
Type of bar screen
a.Manual
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b.Mechanical
Are the bars adequately screening debris?
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Is the screen free of excessive debris?
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Is disposal of screening in compliance?
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Is the unit in good condition?
0
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Comment:
Page# 5

Permit: NCO024945
Inspection Date: 11/09/2022
Pump Station - Influent
Is the pump wet well free of bypass lines or structures?
Is the wet well free of excessive grease?
Are all pumps present?
Are all pumps operable?
Are float controls operable?
Is SCADA telemetry available and operational?
Is audible and visual alarm available and operational?
Comment:
Flow Measurement - Influent
# Is flow meter used for reporting?
Is flow meter calibrated annually?
Owner -Facility: Irwin Creek WWTP
Inspection Type: Compliance Evaluation
Is the flow meter operational?
(If units are separated) Does the chart recorder match the flow meter?
Comment: The flow meter is calibrated twice
LLC.
Grit Removal
Type of grit removal
Yes No NA NE
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and was calibrated on 7/28/2022 by CITI
Yes No NA NE
a.Manual
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b.Mechanical
Is the grit free of excessive organic matter?
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Is the grit free of excessive odor?
0
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# Is disposal of grit in compliance?
0
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Comment: Screenings and grit are disposed at the Republic
Services/CMS Landfill located in
Cabarrus Countv.
Primary Clarifier
Yes
No
NA NE
Is the clarifier free of black and odorous wastewater?
0
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Is the site free of excessive buildup of solids in center well of circular clarifier?
0
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Are weirs level?
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Is the site free of weir blockage?
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Is the site free of evidence of short-circuiting?
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Is scum removal adequate?
0
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Page# 6

Permit: NCO024945
Owner -Facility: Irwin Creek WWTP
Inspection Date: 11/09/2022
Inspection Type: Compliance Evaluation
Primary Clarifier
Yes
No
NA
NE
Is the site free of excessive floating sludge?
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Is the drive unit operational?
0
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Is the sludge blanket level acceptable?
0
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Is the sludge blanket level acceptable? (Approximately'/4
of the sidewall depth) 0
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Comment: All three primaries were operational: however, only one was in service.
Aeration Basins
Yes
No
NA
NE
Mode of operation
Ext. Air
Type of aeration system
Diffused
Is the basin free of dead spots?
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Are surface aerators and mixers operational?
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Are the diffusers operational?
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Is the foam the proper color for the treatment process?
0
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Does the foam cover less than 25% of the basin's surface?
0
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Is the DO level acceptable?
0
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Is the DO level acceptable?(1.0 to 3.0 mg/1)
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Comment: All seven aeration basins were operational and in service. Each aeration basin is
equipped with an anoxic zone with mixing. Magnesium hydroxide is added
prior to the
aeration basins to maintain appropriate alkalinity/pH levels.
Chemical Feed
Yes
No
NA NE
Is containment adequate?
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Is storage adequate?
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Are backup pumps available?
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Is the site free of excessive leaking?
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Comment: The facility is equipped with a chemical feed and storage facility for alum and
magnesium hydroxide.
Secondary Clarifier
Yes
No
NA
NE
Is the clarifier free of black and odorous wastewater?
0
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Is the site free of excessive buildup of solids in center well of circular clarifier?
0
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Are weirs level?
0
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Is the site free of weir blockage?
0
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Is the site free of evidence of short-circuiting?
0
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Page# 7

Permit: NC0024945
Inspection Date: 11/09/2022
Owner -Facility: Irwin Creek WWTP
Inspection Type: Compliance Evaluation
Secondary Clarifier
Yes
No
NA
NE
Is scum removal adequate?
0
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Is the site free of excessive floating sludge?
0
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Is the drive unit operational?
0
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Is the return rate acceptable (low turbulence)?
0
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Is the overflow clear of excessive solids/pin floc?
0
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Is the sludge blanket level acceptable? (Approximately'/4
of the sidewall depth) 0
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Comment: All four secondaries were operational: however, only three were in service.
Pumps-RAS-WAS
Yes
No
NA
NE
Are pumps in place?
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Are pumps operational?
0
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Are there adequate spare parts and supplies on site?
0
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Comment:
Filtration (High Rate Tertiary)
Yes
No
NA
NE
Type of operation:
Down flow
Is the filter media present?
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Is the filter surface free of clogging?
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Is the filter free of growth?
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Is the air scour operational?
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Is the scouring acceptable?
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Is the clear well free of excessive solids and filter media?
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Comment: All ten tertiary filters were operational and in service.
Disinfection - UV
Yes
No
NA
NE
Are extra UV bulbs available on site?
0
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Are UV bulbs clean?
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Is UV intensity adequate?
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Is transmittance at or above designed level?
0
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Is there a backup system on site?
0
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Is effluent clear and free of solids?
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Comment: Both UV channels were operational.
Page# 8

Permit: NCO024945 Owner -Facility:
Inspection Date: 11/09/2022 Inspection Type:
Irwin Creek WWTP
Compliance Evaluation
Flow Measurement - Effluent
Yes
No
NA
NE
# Is flow meter used for reporting?
0
❑
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Is flow meter calibrated annually?
0
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Is the flow meter operational?
0
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(If units are separated) Does the chart recorder match the flow meter?
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0
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Comment: The flow meter is calibrated twice per year and was calibrated on 7/28/2022 by CITI
LLC.
Effluent Pipe
Yes
No
NA
NE
Is right of way to the outfall properly maintained?
0
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Are the receiving water free of foam other than trace amounts and other debris?
0
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If effluent (diffuser pipes are required) are they operating properly?
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Comment: The effluent appeared clear with no floatable solids or foam. The receiving stream did
not appear to be negatively impacted. Fish were observed at the confluence of the
effluent discharge and receiving stream.
Anaerobic Digester
Type of operation:
Is the capacity adequate?
# Is gas stored on site?
Is the digester(s) free of tilting covers?
Is the gas burner operational?
Is the digester heated?
Is the temperature maintained constantly?
Is tankage available for properly waste sludge?
Yes No NA NE
Fixed cover
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Comment: The facility is equipped with four primary anaerobic digesters and two storage tanks
(floating cover). Three primary digesters and one storage tank were in service. The
fourth primary digester was in the process of being cleaned out by a contracted
company (Bio-Nomic Services).
Solids Handling Equipment
Is the equipment operational?
Is the chemical feed equipment operational?
Is storage adequate?
Is the site free of high level of solids in filtrate from filter presses or vacuum filters?
Is the site free of sludge buildup on belts and/or rollers of filter press?
Is the site free of excessive moisture in belt filter press sludge cake?
Yes No NA NE
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Page# 9

Permit: NC0024945
Inspection Date: 11/09/2022
Solids Handling Equipment
The facility has an approved sludge management plan?
Owner -Facility: Irwin Creek WWTP
Inspection Type: Compliance Evaluation
Yes No NA NE
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Comment: The facility is equipped with 2-gravity belt thickeners, 2-belt filter presses, WAS storaqe
tank (aerated), filtrate storage tank (aerated), bio-solids storage tank and a covered
bio-solids storage pad. All treatment units were operational.
Dewatered bio-solids are land applied by a contract company (Syangro) under the
authority of Permit No. WQ00O0057.
Standby Power
Yes
No
NA
NE
Is automatically activated standby power available?
■
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Is the generator tested by interrupting primary power source?
■
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Is the generator tested under load?
0
❑
❑
❑
Was generator tested & operational during the inspection?
M
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Do the generator(s) have adequate capacity to operate the entire wastewater site?
0
❑
❑
❑
Is there an emergency agreement with a fuel vendor for extended run on back-up
M
❑
❑
❑
power?
Is the generator fuel level monitored?
0
❑
❑
❑
Comment: Both backup generators are tested under load monthly and serviced quarter)
Carolina CAT.
Page# 10