NC0069841_Fact Sheet_20240629

Fact Sheet
NPDES Permit No. NCO069841
Permit Writer/Email Contact:Nick Coco,[e-mail]
Date: April 23,2024
Division/Branch:NC Division of Water Resources/NPDES Municipal Permitting
Fact Sheet Template: Version 09Jan2017
Permitting Action:
❑X 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: Union County Water/Crooked Creek Wastewater Treatment Plant
(WWTP)#2
Applicant Address: 500 North Main Street,Monroe,NC 28112
Facility Address: 4015 Sardis Church Road,Monroe,NC 28110
Permitted Flow: 1.9 MGD
Facility Type/Waste: MAJOR Municipal; 100%domestic
Facility Class: Grade III Biological Water Pollution Control System
Treatment Units: Bar Screens, Oxidation Ditches,Aerators, Clarifiers,Activated Sludge,
Sand Filters,UV Disinfection, Chlorine Contact and Dechlorination
(backup), Cascade Aeration,Aerobic Digesters
Pretreatment Program(Y/N) N
County: Union
Region Mooresville
Briefly describe the proposed permitting action and facility background: Union County Water has applied
for an NPDES permit renewal at 1.9 MGD for the Crooked Creek WWTP#2. This facility serves a
population of approximately 16,000 residents. Treated domestic wastewater is discharged via Outfall 001
into North Fork Crooked Creek, a class C waterbody in the Yadkin-Pee Dee River Basin. Outfall 001
located approximately 2.7 miles from the treatment works and is approximately 48 miles upstream of
waters designated as WS-V; B.
Inflow and Infiltration(1/1): In their application,Union County Water indicated approximately 0.2 MGD
of I/1 is experienced at the Crooked Creek WWTP#2. The permittee has addressed key manhole defects
and PVC cleanouts to mitigate 1/1.
Page 1 of 11

Sludge disposal: "Solids are wasted to one of 5 digesters on site until the point they are filled. Once full,
the air is turned off and they are settled out and decanted.Air is then turned back on, digestor is
refilled and continued until the sludge is 3.0%or we are no longer able to decant. From that point the
sludge is then transferred to a fifth digester that is used for Land Application under WQ0007486. A 3rd
party contractor then performs the lime stabilization, sampling, field preparation and land application."
2. Receiving Waterbody Information:
Receiving Waterbody Information
Outfalls/Receiving Stream(s): Outfall 001 -North Fork Crooked Creek
Stream Segment: 13-17-20-1
Stream Classification: C
Drainage Area(mi): 13.65
Summer 7Q10(cfs) 0
Winter 7Q10(cfs): 0.2
30Q2 (cfs): 0.4
Average Flow(cfs): 13
IWC (%effluent): 100
2022 303(d) listed/parameter: Yes; exceeding criteria for turbidity and benthos; Data
inconclusive for fecal coliform
Subject to TMDL/parameter: Yes- State wide Mercury TMDL implementation.
Basin/HUC: Yadkin-Pee Dee River/03040105
USGS Topo Quad: G16SE
3. Effluent Data Summary
Effluent data for Outfall 001 is summarized below for the period of September 2019 through February
2024.
Table 1. Effluent Data Summary Outfall 001
Parameter Units Average Max Min Permit
Limit
Flow MGD 1.0 3.268 0.276 MA 1.9
BOD summer mg/l 2.5 22.9 <2 WA 7.5
MA 5.0
BOD winter mg/1 2.9 24 <2 WA 15.0
MA 10.0
NH3N summer mg/1 0 17 1.34 <0.1 WA 3.0
MA 1.0
NH3N winter mg/l 0.17 10 <0.1 WA 5.7
MA 1.9
TSS mg/l 3.7 38.33 2.5 WA 45.0
MA 30.0
0>pH<
pH SU 7.2 7.83 5.9 6. 9.0
(geomean)
(geometric)
Fecal coliform #/100 ml 2.0 1553.1 < 1 WA 400
MA 200
DO mg/1 9.0 14.01 6.03 DA>6.0
Page 2 of 11

WA 17.0
TRC* µg/l < 15 < 15 < 15 DM 28.0
(<50
compliance)
Temperature ° C 19.3 28.3 9.5 Monitor&
Report
TN mg/1 30.0 54.7 12.06 Monitor&
Report
TP mg/1 2.5 24 0.19 Monitor&
Report
Total Silver µg/1 < 1 <5 <0.5 Monitor&
Report
Total Hardness mg/l 151 232.6 89 Monitor&
Report
MA-Monthly Average,WA-Weekly Average,DM-Daily Maximum,DA=Daily Average
*Total Residual Chlorine(TRC)was monitored once during the review period. The facility uses UV
disinfection as the primary means of disinfection, and as such TRC monitoring is only conducted when
backup chlorination is used or in the event that the Permittee conducts a voluntary sampling event.
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/l 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).
Is this facility a member of a Monitoring Coalition with waived instream monitoring(YIN): YES
Name of Monitoring Coalition: Yadkin-Pee Dee River Basin Association
If applicable, summarize any instream data and what instream monitoring will be proposed for this
permit action: The current permit requires instream monitoring for dissolved oxygen,temperature, and
fecal coliform upstream at least 50 feet above the outfall and downstream '/4 miles below the outfall at SR
1514. Instream monitoring is conducted three times per week during June,July,August and September,
and once per week during the rest of the year. As the Permittee is a member of the Yadkin-Pee Dee River
Basin Association(YPDRBA), instream monitoring requirements are provisionally waived. The nearest
upstream YPDRBA monitoring station is Q8386000, located approximately 1.4 miles upstream of the
outfall. The nearest downstream YPDRBA monitoring station is Q8386200, located approximately 0.9
miles downstream of the outfall. Data were observed from September 2019 through February 2024. The
data have been summarized in Table 2 below.
Table 2. Instream Monitoring Data Summary
Upstream Downstream
Parameter Units
Average Max Min Average Max Min
Temperature ° C 17.6 26.1 3.9 18.5 29.5 4.6
DO mg/1 6.2 11.4 0.8 7.4 10.7 4.5
Fecal coliform #/100 ml (geomean) 9400 58 (geomean) 6000 66
509 386
Page 3 of 11

Students t-tests were run at a 95% confidence interval to analyze relationships between instream
samples.A statistically significant difference is determined when the t-test p-value result is<0.05.
Downstream temperature was greater than 29 degrees Celsius [per 15A NCAC 02B .0211 (18)] on one
occasion during the period reviewed. Downstream temperature was greater than upstream temperature by
more than 2.8 degrees Celsius on 3 occasions during the period reviewed. Review of concurrent effluent
temperature data demonstrated effluent temperatures greater than downstream temperatures on only one
occasion. It appears that,while the effluent temperature may on occasion influence the instream
temperature,upstream to downstream temperature differentials are likely impacted by variables outside of
the WWTP effluent. It was concluded that a statistically significant difference exists between upstream
and downstream temperature.No changes are proposed to instream temperature monitoring requirements.
Downstream DO was observed below 5 mg/L [per 15A NCAC 02B .0211 (6)] on one occasion but not
below 4 mg/L during the period reviewed. It was concluded that a statistically significant difference exists
between upstream and downstream DO, due to downstream DO being consistently higher than upstream
DO.No changes are proposed to instream DO monitoring requirements.
It was concluded that a statistically significant difference exists between upstream and downstream fecal
coliform. Review of available instream data from YPDRBA demonstrated fluctuation between reported
levels of fecal coliform upstream being higher than those downstream and vice versa. Review of
concurrent effluent data does not appear to display a correlation between elevated fecal coliform in the
discharge and elevated levels downstream.No changes are proposed to instream fecal coliform
monitoring requirements.
YPDRBA also conducts sampling for conductivity,pH and turbidity. Data were observed from
September 2019 through February 2024. The data has been summarized in Table 3 below.
Table 3. Instream Monitoring Data Summary
Upstream Downstream
Parameter Units
Average Max Min Average Max Min
Conductivity µmhos/cm 167 397 50 315 668 58
Turbidity NTU 45 140 4.4 39 160 4.4
pH s.u. 7.0 7.5 6.3 7.0 7.6 6.4
It was concluded that a statistically significant difference exists between upstream and downstream
conductivity, due to downstream conductivity being consistently higher than upstream conductivity. As
the facility is the only discharger between the two YPDRBA stations and has no noted significant
industrial users, instream and effluent conductivity monitoring has been added to the permit to track
potential unidentified industrial sources.
Upstream turbidity was greater than 50 NTUs on 18 occasions while downstream turbidity was greater
than 50 NTUs on 15 occasions during the period reviewed [per 15A NCAC 02B .0211(21)]. It was
concluded that no statistically significant difference exists between upstream and downstream turbidity.
pH was observed between 6.0 and 9.0 standard units at both locations during the period reviewed [per
15A NCAC 02B .0211(14)]. It was concluded that no statistically significant difference exists between
upstream and downstream pH.
The facility is located approximately 2.7 miles from its outfall. While this distance is significant, review
of instream DO, fecal coliform and pH data indicate no apparent issues with bacterial regrowth,pH
imbalance or DO consumption in-pipe.As such, sampling at the facility is considered representative of
the discharge.
Page 4 of 11

5. Compliance Summary
Summarize the compliance record with permit effluent limits (past 5 years): The facility reported 1 pH
limit violation resulting in enforcement in 2019.
Summarize the compliance record with aquatic toxicity test limits and any second species test results
(past 5 years): The facility passed 17 of 17 quarterly chronic toxicity tests, as well as all 4 second species
chronic toxicity tests from January 2020 to January 2024.
Summarize the results from the most recent compliance inspection: The last facility inspection conducted
in September 2023 reported that the facility was compliant.
6. Water Quality-Based Effluent Limitations (WQBELs)
Dilution and Mixin Zg ones
In accordance with 15A NCAC 213.0206,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/l for Municipals)may be appropriate if deemed more stringent based on dilution and
model results.
If permit limits are more stringent than TBELs, describe how limits were developed: Limitations for
BOD were set at 5 mg/L to protect the DO standard per 15 NCAC 02B .0206(d)(1) for flow design
criteria,where critical flows of the receiving stream are 7Q10=0 cfs and 30Q2>0 cfs.
A Streeter Phelps model(Level B)was run for speculative limits in 2008,but was deemed inappropriate.
It was noted:
"On January 23, 2008 Hazen &Sawyer sent a letter on behalf of Union County requesting speculative
effluent limits for a potential expansion at the Crooked Creek WWTP. The Division responded on May 7,
2008[that they were]unable to provide Crooked Creek with speculative limits since the model proved to
be an inappropriate tool because it was unable to reflect the actual conditions (low dissolved oxygen) in
the existing stream. The Division was also notable to provide speculative limits for a discharge to South
Forth Crooked Creek because new discharges are not permitted to streams having a zero, summer 7Q10,
and 30Q2. It was suggested that the County explore any and all alternatives other than a NPDES
discharge due to the limited stream flow and low dissolved oxygen levels in the local streams."
No changes are proposed.
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 5 of 11

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 current
permit contains a weekly average limit for TRC of 17 µg/L and a daily maximum limit for TRC of 28
µg/L. TRC limits have been reviewed in the attached WLA. Based on the 15A NCAC 02B .0211(3) TRC
standard of 17 µg/L and accounting for instream wasteload concentration/dilution, a daily maximum limit
of 17 µg/L was calculated. As the calculated limit is more restrictive than the current permit requirements,
a daily maximum limit of 17 µg/L has been proposed. TRC monitoring is only required in the event the
facility uses its backup chlorination disinfection system.
The existing limitations for ammonia,which took effect January 31,2022, are based on ammonia toxicity.
As the effective date of the ammonia limits have passed,reference to prior ammonia limitations and the
schedule of compliance for ammonia have been removed. The ammonia limits have been reviewed in the
attached WLA 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.
Effluent hardness data were provided by the Permittee from September 2019 to February 2024.As the
7Q10s for the receiving stream is estimated to be 0 cfs, no upstream hardness monitoring is required for
this discharge.
A reasonable potential analysis was conducted on effluent toxicant data collected between June 2018 and
October 2022. 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 Monitoriniz. 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: Total Cadmium(MA 3.9 ug/L, DM 16.0 ug/L),Total Cyanide
(MA 5.0 ug/L, DM 22.0 ug/L), Total Selenium(MA 3.1 ug/L, DM 56.0 ug/L)
• 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: None
• 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 Cyanide, Total Selenium, Total Silver,
Total Zinc
• POTW Effluent Pollutant Scan Review: Three effluent pollutant scans were evaluated for
additional pollutants of concern.
Page 6 of 11

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
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, Chlorides, Total Phenolic Compounds,Bis(2-ethylhexyl)phthalate
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 90%
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/l.
Table 3. Mercury Effluent Data Summary
2020 2021 2022 2023 2024
#of Samples 1 1 6 12 2
Annual Average Conc. n /L 0.8 0.5 1.7 1.76 1.13
Maximum Conc.,n /L 0.83 0.5 3.91 7.1 1.47
TBEL,n /L 47
WQBEL,n /L 12.0
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 capacity is less than 2.0 MGD no mercury minimization plan(MMP)
special condition is required.
Page 7 of 11

Other TMDL/Nutrient Management Strategy Considerations
If applicable, describe any other TMDLs/Nutrient Management Strategies and their implementation
within this permit: NA
Other WQBEL Considerations
If applicable, describe any other parameters of concern evaluated for WQBELs: 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 via a Chemical Addendum to NPDES Application table. Union County Water responded to
the DWR additional information request regarding the chemical addendum in a 5/21/2024 email
(attached)noting, "All pollutants are reported on the DMR."
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; The current permit
contains a schedule of compliance for ammonia-nitrogen limits. As the compliance deadline has been
passed,the special condition has been removed.
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 (if not applicable,delete and skip to Industrials)
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 BODS/TSS 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 2B.0201. Each applicant for a new/expanding NPDES permit
must document an effort to consider non-discharge alternatives per 15A NCAC 2H.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(YES/NO): NO
If YES, confirm that antibacksliding provisions are not violated:NA
Page 8 of 11

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.
For calculation of Total Nitrogen,reporting of TKN and NO2+NO3 has been added to the permit.
As the Crooked Creek WWTP#2 is a major facility discharging above WS-V waters,monitoring of
PFAS chemicals will be added to the permit at a frequency of quarterly. As the facility treats 100%
domestic wastewater with no known significant industrial users,the PFAS sampling requirement in the
Permit includes a compliance schedule which delays the effective date of this requirement until the first
full calendar quarter beginning 6 months after EPA has a final wastewater method in 40 CFR136
published in the Federal Register. This date may be extended upon request and if there are no NC-
certified labs.
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 4. Current Permit Conditions and Proposed Changes Outfall 001
Parameter Current Permit Proposed Change Basis for Condition/Change
Flow MA 1.9 MGD No change 15A NCAC 2B .0505
BOD5 Summer: No change WQBEL. Zero flow policy- 15 NCAC
MA 5.0 mg/l 02B .0206(d)(1); Surface Water
WA 7.5 mg/1 Monitoring, 15A NCAC 2B. 0500
Winter:
MA 10.0 mg/l
WA 15.0 mg/1
Monitor and report 3/Week
NH3-N Summer: No change WQBEL. 2024 WLA; Surface Water
MA 1.0 mg/l Monitoring, 15A NCAC 2B. 0500
WA 3.0 mg/1
Winter:
MA 1.9 mg/l
WA 5.7 mg/1
Monitor and report 3/Week
TSS MA 30.0 mg/l No change TBEL. Secondary treatment standards/40
WA 45.0 mg/l CFR 133 / 15A NCAC 213 .0406;
Monitor and report 3/Week Surface Water Monitoring, 15A NCAC
2B. 0500
Page 9 of 11

Fecal MA 200/100ml No change WQBEL. State WQ standard, 15A
coliform WA 400/100ml NCAC 2B .0200; Surface Water
Monitor and report 3/Week Monitoring, 15A NCAC 2B. 0500
Temperature Monitor and Report Daily No change Surface Water Monitoring, 15A NCAC
2B. 0508
DO >6.0 mg/l No change WQBEL. State WQ standard, 15A
Monitor and Report 3/week NCAC 2B .0200; 15A NCAC 02B .0500
pH 6—9 SU No change WQBEL. State WQ standard, 15A
Monitor and Report 3/week NCAC 213 .0200; 15A NCAC 02B .0500
Conductivity No requirement Monitor and Surface Water Monitoring, 15A NCAC
Report 3/Week 2B. 0500—based on instream
conductivity review
Total WA 17 ug/L DM 17 ug/L WQBEL. 2024 WLA. Surface Water
Residual DM 28 ug/L No change to Monitoring, 15A NCAC 2B. 0500
Chlorine Monitor and Report 3/week monitoring
TKN No requirement Monitor and For calculation of TN
Report Monthly
NO2+NO3 No requirement Monitor and For calculation of TN
Report Monthly
Total Monitor and Report No change Surface Water Monitoring, 15A NCAC
Nitrogen Monthly 2B. 0500
Total Monitor and Report No change Surface Water Monitoring, 15A NCAC
Phosphorus Monthly 2B. 0500
Total Silver Monitor and report Remove Based on results of Reasonable Potential
Quarterly requirement Analysis (RPA);All non-detect<5 ug/L,
< 1 ug/L and<0.5 ug/L-no monitoring
required
Total No requirement MA 3.9 ug/1 Based on results of Reasonable Potential
Cadmium DM 16.0 ug/1 Analysis (RPA); RP shown- apply
Monitor and Monthly Monitoring with Limit
report Monthly
Total No requirement MA 3.1 ug/1 Based on results of Reasonable Potential
Selenium DM 56.0 ug/1 Analysis (RPA); RP shown- apply
Monitor and Monthly Monitoring with Limit
report Monthl
Total No requirement MA 5.0 ug/1 Based on results of Reasonable Potential
Cyanide DM 22.0 ug/1 Analysis (RPA); RP shown- apply
Monitor and Monthly Monitoring with Limit
report Monthl
Total Quarterly monitoring of No changes Hardness-dependent dissolved metals
Hardness Effluent water quality standards approved in 2016
Instream Monitor and report for Add conductivity Based on Instream Data Review
Monitoring temperature,DO and fecal
coliform
Add quarterly Evaluation of PFAS contribution: major
monitoring with discharger above WS-V waters;
PFAS No requirement delayed Implementation delayed until after EPA
implementation certified 40 CFR method becomes
available.
Page 10 of 11

Toxicity Test Chronic limit, 90% effluent No change WQBEL. No toxics in toxic amounts.
15A NCAC 213.0200 and 15A NCAC
213.0500
Effluent Three times per permit No change; 40 CFR 122
Pollutant cycle conducted in
Scan 2025, 2026, 2027
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(919) 707-3609 or via email at nick.cocokdeq.nc.gov.
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
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
• Monitoring Frequency Reduction Evaluation
• WET Testing and Self-Monitoring Summary
• Compliance Inspection Report
• Requested Additional Information
Page 11 of 11

Freshwater RPA- 95% Probability/95% Confidence Using Metal Translators
MAXIMUM DATA POINTS= 58
REQUIRED DATA ENTRY
Table 1. Project Information Table 2. Parameters of Concern
❑CHECK IF HQW OR ORW WQS Name WQS Type Chronic Modifier Acute PQL Units
Facility Name Crooked Creek WWTP#2 Par01 Arsenic Aquactic Life C 150 FW 340 ug/L
WWTP/WTP Class III Par02 Arsenic Human Health C 10 HH/WS N/A ug/L
Water Supply
NPDES Permit NCO069841 Par03 Beryllium Aquatic Life NC 6.5 FW 65 ug/L
Outfall 001 Par04 Cadmium Aquatic Life NC 3.8814 FW 15.9602 ug/L
Flow,Qw(MGD) 1.900 Par05 Chlorides Aquatic Life NC 230 FW mg/Li
Receiving Stream North Fork Crooked Creek Par061411, Chlorinated Phenolic Compounds Water Supply NC 1 A ug/L
HUC Number 03040105 Par07 Total Phenolic Compounds Aquatic Life NC 300 A ug/L
Stream Class C Par08 Chromium III Aquatic Life NC 514.1529 FW 3952.6066 ug/L
❑Apply WS Hardness WQC Par09 Chromium VI Aquatic Life NC 11 FW 16 pg/L
Lentic or Lotic Lotic Par10 Chromium,Total Aquatic Life NC N/A FW N/A Ng/L
7Q10s(cfs) 0.000 Par91 Copper Aquatic Life NC 36.6865 FW 57.0858 ug/L
7Q10w(cfs) 0.20 Par12 Cyanide Aquatic Life NC 5 FW 22 10 1 ug/L
30Q2(cfs) 0.40 Par13 Fluoride Aquatic Life NC 1,800 FW ug/L
QA(cfs) 13.00 Par14 Lead Aquatic Life NC 21.4031 FW 549.2400 ug/L
1Q10s(cfs) 0.00 Par15 Mercury Aquatic Life NC 12 FW 0.5 ng/L
Effluent Hardness 151.22 mg/L(Avg) Par16 Molybdenum Human Health NC 2000 HH ug/L
_Upstream Hardness I 25 mg/L(Avg) I Par17 Nickel Aquatic Life NC 170.6907 FW 1536.7966 pg/L
_
_Combined Hardness Chronic_I 151.22 mg/L I Par18 Nickel Water Supply NC 25.0000 WS N/A pg/L
Combined Hardness Acute 151.22 mg/L Par19 Selenium Aquatic Life NC 3.1 FW 56 ug/L
--------------------
Data Source(s) Freshwater Dissolved Selenium Standard used per Par20 Silver Aquatic Life NC 0.06 FW 6.5519 ug/L
❑CHECK TO APPLY MODEL the 2020-2022 Surface Water Triennial Review Par21 Zinc Aquatic Life NC 582.3829 FW 577.6577 ug/L
updates.Total selenium data used for analysis as no
dissolved selenium data are available. Par22 Bis(2-ethylhexyl)phthalate Human Health C 0.37 HH pg/L
Par23
Par24
Par25
69841 RPA, input
5/31/2024

REASONABLE POTENTIAL ANALYSIS
1-11 Use"PASTE SPECIAL H2 Use"PASTE SPECIAL
Effluent Hardness Values"then"COPY" Upstream Hardness Values"then"COPY"
Maximum data .Maximum data
points=58 points=58
Date Data BDL=1/2DL Results Date Data BDL=1/2DL Results
1 9/10/2019 200 200 Std Dev. 33.2744 1 Default 25 25 Std Dev. N/A
2 10/7/2019 170 170 Mean 151.2237 2 Mean 25.0000
3 11/14/2019 130 130 C.V. 0.2200 3 C.V. 0.0000
4 12/5/2019 180 180 n 38 4 n 1
5 1/6/2020 89 89 10th Per value 110.00 mg/L 5 10th Per value 25.00 mg/L
6 2/12/2020 130 130 Average Value 151.22 mg/L 6 Average Value 25.00 mg/L
7 3/4/2020 110 110 Max. Value 232.60 mg/L 7 Max. Value 25.00 mg/L
8 5/6/2020 110 110 8
9 5/20/2020 110 110 9
10 8/12/2020 140 140 10
11 11/12/2020 130 130 11
12 2/10/2021 120 120 12
13 6/23/2021 120 120 13
14 8/4/2021 160 160 14
15 11/10/2021 214 214 15
16 2/9/2022 112.4 112.4 16
17 5/11/2022 91.1 91.1 17
18 7/20/2022 178 178 18
19 8/10/2022 176.4 176.4 19
20 9/8/2022 164 164 20
21 10/5/2022 134 134 21
22 11/2/2022 232.6 232.6 22
23 11/9/2022 176 176 23
24 1/4/2023 150 150 24
25 2/8/2023 160 160 25
26 2/15/2023 136.7 136.7 26
27 3/8/2023 156 156 27
28 4/5/2023 153 153 28
29 5/4/2023 127.3 127.3 29
30 6/7/2023 162 162 30
31 7/12/2023 180 180 31
32 8/9/2023 144 144 32
33 9/6/2023 152 152 33
34 10/4/2023 168 168 34
35 11/8/2023 190 190 35
36 12/6/2023 188 188 36
37 1/10/2024 121 121 37
38 2/7/2024 181 181 38
39 39
40 40
41 41
42 42
43 43
44 44
45 45
46 46
47 47
48 48
49 49
50 50
51 51
52 52
53 53
54 54
55 55
56 56
57 57
58 58
69841 RPA, data
- 1 - 5/31/2024

REASONABLE POTENTIAL ANALYSIS
Par01 & Par02
Use"PASTE SPECIAL
Arsenic Values"then"COPY"
Maximum data
points=58
Date Data BDL=1/2DL Results
1 5/6/2020 < 5 2.5 Std Dev. 1.6684
2 8/12/2020 < 5 2.5 Mean 2.0560
3 8/4/2021 < 10 5 C.V. 0.8115
4 7/20/2022 < 2 1 n 25
5 8/10/2022 < 2 1
6 9/8/2022 < 2 1 Mult Factor= 1.36
7 10/5/2022 < 2 1 Max. Value 5.0 ug/L
8 11/2/2022 < 6.4 3.2 Max. Pred Cw 6.8 ug/L
9 11/9/2022 < 2 1
10 12/7/2022 < 2 1
11 1/4/2023 < 2 1
12 2/8/2023 < 6.4 3.2
13 2/15/2023 < 2 1
14 3/8/2023 < 2 1
15 4/5/2023 < 2 1
16 5/4/2023 < 2 1
17 6/7/2023 < 2 1
18 7/12/2023 < 2 1
19 8/9/2023 < 2 1
20 9/6/2023 < 1 0.5
21 10/4/2023 < 1 0.5
22 11/8/2023 < 10 5
23 12/6/2023 < 10 5
24 1/10/2024 < 10 5
25 2/7/2024 < 10 5
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
69841 RPA, data
-2 - 5/31/2024

REASONABLE POTENTIAL ANALYSIS
Par03 Use"PASTE SPECIAL Par04 Use"PASTE SPECIAL
Beryllium Values"then"COPY" Cadmium Values"then"COPY"
Maximum data .Maximum data
points=58 points=58
Date Data BDL=1/2DL Results Date Data BDL=1/2DL Results
1 5/6/2020 < 2 1 Std Dev. 1.1083 1 5/6/2020 < 0.5 0.25 Std Dev. 10.5587
2 8/4/2021 < 5 2.5 Mean 0.9500 2 8/12/2020 < 0.5 0.25 Mean 2.3296
3 11/2/2022 < 0.3 0.15 C.V. (default) 0.6000 3 8/4/2021 < 2 1 C.V. 4.5324
4 2/8/2023 < 0.3 0.15 n 4 4 7/20/2022 < 0.15 0.075 n 25
5 5 8/10/2022 < 0.15 0.075
6 Mult Factor= 2.59 6 9/8/2022 < 0.15 0.075 Mult Factor= 2.14
7 Max. Value 2.50 ug/L 7 10/5/2022 < 0.15 0.075 Max. Value 53.000 ug/L
8 Max. Pred Cw 6.48 ug/L 8 11/2/2022 < 0.44 0.22 Max. Pred Cw 113.420 ug/L
9 9 11/9/2022 < 0.15 0.075
10 10 12/7/2022 < 0.15 0.075
11 11 1/4/2023 < 0.15 0.075
12 12 2/8/2023 < 0.44 0.22
13 13 2/15/2023 < 0.15 0.075
14 14 3/8/2023 < 0.15 0.075
15 15 4/5/2023 < 0.15 0.075
16 16 5/4/2023 < 0.15 0.075
17 17 6/7/2023 < 0.15 0.075
18 18 7/12/2023 < 0.15 0.075
19 19 8/9/2023 < 0.15 0.075
20 20 9/6/2023 < 0.5 0.25
21 21 10/4/2023 53 53
22 22 11/8/2023 < 1 0.5
23 23 12/6/2023 < 1 0.5
24 24 1/10/2024 < 1 0.5
25 25 2/7/2024 < 1 0.5
26 26
27 27
28 28
29 29
30 30
31 31
32 32
33 33
34 34
35 35
36 36
37 37
38 38
39 39
40 40
41 41
42 42
43 43
44 44
45 45
46 46
47 47
48 48
49 49
50 50
51 51
52 52
53 53
54 54
55 55
56 56
57 57
58 58
69841 RPA, data
-3- 5/31/2024

REASONABLE POTENTIAL ANALYSIS
Par05 Par07 use"PASTE
Use"PASTE SPECIAL-
Values"then"COPY". SPECIAL-Values"
Chlorides Maximum data points= Total Phenolic Compounds then"COPY".
58 Maximum data
Date Data BDL=1/2DL Results Date Data BDL=1/2DL Results points=58
1 9/14/2022 46.9 46.9 Std Dev. 5.7735 1 5/6/2020 < 50 25 Std Dev. 6.0069
2 3/15/2023 46.9 46.9 Mean 50.2 2 8/4/2021 19 19 Mean 17.2500
3 9/20/2023 56.9 56.9 C.V. (default) 0.6000 3 11/2/2022 < 25 12.5 C.V. (default) 0.6000
4 n 3 4 2/8/2023 < 25 12.5 n 4
5 5
6 Mult Factor= 3.0 6 Mult Factor= 2.59
7 Max. Value 56.9 mg/L 7 Max. Value 25.0 ug/L
8 Max. Pred Cw 170.7 mg/L 8 Max. Pred Cw 64.8 ug/L
9 9
10 10
11 11
12 12
13 13
14 14
15 15
16 16
17 17
18 18
19 19
20 20
21 21
22 22
23 23
24 24
25 25
26 26
27 27
28 28
29 29
30 30
31 31
32 32
33 33
34 34
35 35
36 36
37 37
38 38
39 39
40 40
41 41
42 42
43 43
44 44
45 45
46 46
47 47
48 48
49 49
50 50
51 51
52 52
53 53
54 54
55 55
56 56
57 57
58 58
69841 RPA, data
-4- 5/31/2024

REASONABLE POTENTIAL ANALYSIS
Par10 Use"PASTE SPECIAL Pal 1 Use"PASTE SPECIAL
Chromium, Total Values"then"COPY" Copper Values"then"COPY"
Maximum data .Maximum data
points=58 points=58
Date Data BDL=1/2DL Results Date Data BDL=1/2DL Results
1 5/6/2020 < 5 2.5 Std Dev. 0.7211 1 9/10/2019 10 10 Std Dev. 1.8592
2 8/12/2020 < 5 2.5 Mean 1.5000 2 10/7/2019 9.5 9.5 Mean 9.6250
3 8/4/2021 < 5 2.5 C.V. 0.4807 3 11/14/2019 9.5 9.5 C.V. 0.1932
4 7/20/2022 < 2 1 n 25 4 12/5/2019 6.4 6.4 n 32
5 8/10/2022 2 2 5 1/6/2020 8.1 8.1
6 9/8/2022 < 2 1 Mult Factor= 1.22 6 2/12/2020 5.8 5.8 Mult Factor= 1.06
7 10/5/2022 < 2 1 Max. Value 2.5 pg/L 7 3/4/2020 9.9 9.9 Max. Value 13.10 ug/L
8 11/2/2022 2.3 2.3 Max. Pred Cw 3.1 pg/L 8 5/6/2020 8.8 8.8 Max. Pred Cw 13.89 ug/L
9 11/9/2022 < 2 1 9 8/12/2020 7 7
10 12/7/2022 < 2 1 10 8/4/2021 11 11
11 1/4/2023 < 2 1 11 7/20/2022 12 12
12 2/8/2023 1.2 1.2 12 8/10/2022 12 12
13 2/15/2023 < 2 1 13 9/8/2022 10 10
14 3/8/2023 < 2 1 14 10/5/2022 7 7
15 4/5/2023 < 2 1 15 11/2/2022 10 10
16 5/4/2023 < 2 1 16 11/9/2022 10 10
17 6/7/2023 < 2 1 17 12/7/2022 10 10
18 7/12/2023 < 2 1 18 1/4/2023 8 8
19 8/9/2023 < 2 1 19 2/8/2023 12 12
20 9/6/2023 < 1 0.5 20 2/15/2023 7 7
21 10/4/2023 1 1 21 3/8/2023 11 11
22 11/8/2023 < 5 2.5 22 4/5/2023 11 11
23 12/6/2023 < 5 2.5 23 5/4/2023 8 8
24 1/10/2024 < 5 2.5 24 6/7/2023 10 10
25 2/7/2024 < 5 2.5 25 7/12/2023 11 11
26 26 8/9/2023 8 8
27 27 9/6/2023 10 10
28 28 10/4/2023 8 8
29 29 11/8/2023 11.8 11.8
30 30 12/6/2023 13.1 13.1
31 31 1/10/2024 11.9 11.9
32 32 2/7/2024 10.2 10.2
33 33
34 34
35 35
36 36
37 37
38 38
39 39
40 40
41 41
42 42
43 43
44 44
45 45
46 46
47 47
48 48
49 49
50 50
51 51
52 52
53 53
54 54
55 55
56 56
57 57
58 58
69841 RPA, data
- 5- 5/31/2024

REASONABLE POTENTIAL ANALYSIS
Par12 Use"PASTE SPECIAL Par14 Use"PASTE SPECIAL
Cyanide Values"then"COPY" Lead Values"then"COPY"
Maximum data .Maximum data
points=58 points=58
Date Data BDL=1/2DL Results Date BDL=1/2DL Results
1 5/6/2020 < 10 5 Std Dev. 1.4116 1 5/6/2020 < 5 2.5 Std Dev. 1.8375
2 8/4/2021 < 5 5 Mean 5.42 2 8/12/2020 < 5 2.5 Mean 1.5700
3 7/20/2022 7 5 C.V. 0.2606 3 8/4/2021 < 10 5 C.V. 1.1704
4 8/10/2022 10 10 n 24 4 7/20/2022 < 0.5 0.25 n 25
5 9/8/2022 < 5 5 5 8/10/2022 < 0.5 0.25
6 10/5/2022 < 5 5 Mult Factor= 1.12 6 9/8/2022 < 0.5 0.25 Mult Factor= 1.50
7 11/2/2022 10 10 Max. Value 10.0 ug/L 7 10/5/2022 < 0.5 0.25 Max. Value 5.000 ug/L
8 11/9/2022 < 5 5 Max. Pred Cw 11.2 ug/L 8 11/2/2022 < 6.6 3.3 Max. Pred Cw 7.500 ug/L
9 12/7/2022 < 5 5 9 11/9/2022 < 0.5 0.25
10 1/4/2023 8 5 10 12/7/2022 < 0.5 0.25
11 2/8/2023 < 3 5 11 1/4/2023 < 0.5 0.25
12 2/15/2023 6 5 12 2/8/2023 < 6.6 3.3
13 3/8/2023 6 5 13 2/15/2023 < 0.5 0.25
14 4/5/2023 7 5 14 3/8/2023 0.9 0.9
15 5/4/2023 < 5 5 15 4/5/2023 < 0.5 0.25
16 6/7/2023 < 5 5 16 5/4/2023 < 0.5 0.25
17 7/12/2023 < 5 5 17 6/7/2023 < 0.5 0.25
18 8/9/2023 < 5 5 18 7/12/2023 < 0.5 0.25
19 9/6/2023 < 5 5 19 8/9/2023 < 0.5 0.25
20 10/4/2023 < 5 5 20 9/6/2023 < 1 0.5
21 11/8/2023 < 8 5 21 10/4/2023 < 1 0.5
22 12/6/2023 < 8 5 22 11/8/2023 < 10 5
23 1/10/2024 < 8 5 23 12/6/2023 < 10 5
24 2/7/2024 < 8 5 24 1/10/2024 < 10 5
25 25 2/7/2024 < 5 2.5
26 26
27 27
28 28
29 29
30 30
31 31
32 32
33 33
34 34
35 35
36 36
37 37
38 38
39 39
40 40
41 41
42 42
43 43
44 44
45 45
46 46
47 47
48 48
49 49
50 50
51 51
52 52
53 53
54 54
55 55
56 56
57 57
58 58
69841 RPA, data
-6- 5/31/2024

REASONABLE POTENTIAL ANALYSIS
Par16 Use"PASTE SPECIAL Par17 & Par18 use"PASTE
Values"then"COPY" SPECIAL-Values"
Molybdenum Maximum data Nickel then"COPY".
.
points=58 Maximum data
Date Data BDL=1/2DL Results Date Data BDL=1/2DL Results points=58
1 8/12/2020 5 5 Std Dev. 27.8330 1 5/6/2020 17 17 Std Dev. 8.3955
2 7/20/2022 11 11 Mean 12.1143 2 8/12/2020 15 15 Mean 13.3040
3 8/10/2022 5 5 C.V. 2.2975 3 8/4/2021 < 10 5 C.V. 0.6311
4 9/8/2022 8 8 n 21 4 7/20/2022 29 29 n 25
5 10/5/2022 10 10 5 8/10/2022 11 11
6 11/9/2022 6 6 Mult Factor= 2.06 6 9/8/2022 24 24 Mult Factor= 1.29
7 12/7/2022 4 4 Max. Value 133.0 ug/L 7 10/5/2022 9.9 9.9 Max. Value 35.0 pg/L
8 1/4/2023 9 9 Max. Pred Cw 274.0 ug/L 8 11/2/2022 35 35 Max. Pred Cw 45.2 pg/L
9 2/15/2023 7 7 9 11/9/2022 16.4 16.4
10 3/8/2023 5 5 10 12/7/2022 11.1 11.1
11 4/5/2023 11 11 11 1/4/2023 3.7 3.7
12 5/4/2023 3 3 12 2/8/2023 24 24
13 6/7/2023 4 4 13 2/15/2023 9.8 9.8
14 7/12/2023 2 2 14 3/8/2023 4.9 4.9
15 8/9/2023 4 4 15 4/5/2023 17.2 17.2
16 9/6/2023 2 2 16 5/4/2023 6.3 6.3
17 10/4/2023 6 6 17 6/7/2023 13.3 13.3
18 11/8/2023 < 10 5 18 7/12/2023 6.8 6.8
19 12/6/2023 < 10 5 19 8/9/2023 9.4 9.4
20 1/10/2024 133 133 20 9/6/2023 6.6 6.6
21 2/7/2024 9.4 9.4 21 10/4/2023 16 16
22 22 11/8/2023 < 5 2.5
23 23 12/6/2023 18.5 18.5
24 24 1/10/2024 < 5 2.5
25 25 2/7/2024 17.7 17.7
26 26
27 27
28 28
29 29
30 30
31 31
32 32
33 33
34 34
35 35
36 36
37 37
38 38
39 39
40 40
41 41
42 42
43 43
44 44
45 45
46 46
47 47
48 48
49 49
50 50
51 51
52 52
53 53
54 54
55 55
56 56
57 57
58 58
69841 RPA, data
- 7- 5/31/2024

REASONABLE POTENTIAL ANALYSIS
Par19 Use"PASTE SPECIAL Par20 Use"PASTE SPECIAL
Selenium Values"then"COPY" Silver Values"then"COPY"
Maximum data .Maximum data
points=58 points=58
Date Data BDL=1/2DL Results Date Data BDL=1/2DL Results
1 5/6/2020 < 5 2.5 Std Dev. 2.5775 1 9/10/2019 < 1 0.5 Std Dev. 0.7339
2 8/12/2020 < 5 2.5 Mean 2.3200 2 10/7/2019 < 1 0.5 Mean 0.6474
3 8/4/2021 < 10 5 C.V. 1.1110 3 11/14/2019 < 1 0.5 C.V. 1.1335
4 7/20/2022 < 1 0.5 n 25 4 12/5/2019 < 1 0.5 n 39
5 8/10/2022 < 1 0.5 5 1/6/2020 < 1 0.5
6 9/8/2022 < 1 0.5 Mult Factor= 1.48 6 2/12/2020 < 1 0.5 Mult Factor= 1.20
7 10/5/2022 < 1 0.5 Max. Value 7.5 ug/L 7 3/4/2020 < 1 0.5 Max. Value 2.500 ug/L
8 11/2/2022 < 10 5 Max. Pred Cw 11.1 ug/L 8 5/6/2020 < 1 0.5 Max. Pred Cw 3.000 ug/L
9 11/9/2022 < 1 0.5 9 5/20/2020 < 1 0.5
10 12/7/2022 < 1 0.5 10 8/12/2020 < 1 0.5
11 1/4/2023 3 3 11 11/12/2020 < 1 0.5
12 2/8/2023 < 10 5 12 2/10/2021 < 1 0.5
13 2/15/2023 < 1 0.5 13 6/23/2021 < 1 0.5
14 3/8/2023 < 1 0.5 14 8/4/2021 < 5 2.5
15 4/5/2023 < 1 0.5 15 11/10/2021 < 0.5 0.25
16 5/4/2023 < 1 0.5 16 2/9/2022 < 0.5 0.25
17 6/7/2023 < 1 0.5 17 5/11/2022 < 0.5 0.25
18 7/12/2023 < 1 0.5 18 7/20/2022 < 0.5 0.25
19 8/9/2023 < 1 0.5 19 8/10/2022 < 0.5 0.25
20 9/6/2023 < 1 0.5 20 9/8/2022 < 0.5 0.25
21 10/4/2023 < 1 0.5 21 10/5/2022 < 0.5 0.25
22 11/8/2023 < 15 7.5 22 11/2/2022 < 1.5 0.75
23 12/6/2023 < 15 7.5 23 11/9/2022 < 0.5 0.25
24 1/10/2024 < 15 7.5 24 12/7/2022 < 0.5 0.25
25 2/7/2024 < 10 5 25 1/4/2023 < 0.5 0.25
26 26 2/8/2023 < 1.5 0.75
27 27 2/15/2023 < 0.5 0.25
28 28 3/8/2023 < 0.5 0.25
29 29 4/5/2023 < 0.5 0.25
30 30 5/4/2023 < 0.5 0.25
31 31 6/7/2023 < 0.5 0.25
32 32 7/12/2023 < 0.5 0.25
33 33 8/9/2023 < 0.5 0.25
34 34 9/6/2023 < 0.5 0.25
35 35 10/4/2023 < 0.5 0.25
36 36 11/8/2023 < 5 2.5
37 37 12/6/2023 < 5 2.5
38 38 1/10/2024 < 5 2.5
39 39 2/7/2024 < 5 2.5
40 40
41 41
42 42
43 43
44 44
45 45
46 46
47 47
48 48
49 49
50 50
51 51
52 52
53 53
54 54
55 55
56 56
57 57
58 58
69841 RPA, data
-8- 5/31/2024

REASONABLE POTENTIAL ANALYSIS
Par21 Use"PASTE SPECIAL Par22 Use"PASTE SPECIAL
Zinc Values"then"COPY" Bis (2-ethylhexyl) phthalate Values"then"COPY'
Maximum data .Maximum data
points=58 points=58
Date Data BDL=1/2DL Results Date Data BDL=1/2DL Results
1 1/6/2020 44 44 Std Dev. 13.1809 1 5/6/2020 < 5 2.5 Std Dev. 1.3150
2 2/12/2020 42 42 Mean 45.2031 2 8/4/2021 < 10 5 Mean 2.1500
3 3/4/2020 65 65 C.V. 0.2916 3 9/14/2022 < 3.5 1.75 C.V. (default) 0.6000
4 5/6/2020 32 32 n 32 4 11/2/2022 < 3 1.5 n 7
5 8/12/2020 34 34 5 2/8/2023 < 2.8 1.4
6 8/4/2021 54 54 Mult Factor= 1.09 6 3/15/2023 < 3 1.5 Mult Factor= 2.01
7 7/20/2022 33 33 Max. Value 80.0 ug/L 7 9/20/2023 < 2.8 1.4 Max. Value 5.000000 pg/L
8 8/10/2022 80 80 Max. Pred Cw 87.2 ug/L 8 Max. Pred Cw 10.050000 pg/L
9 9/8/2022 40 40 9
10 10/5/2022 37 37 10
11 11/2/2022 43 43 11
12 11/9/2022 53 53 12
13 12/7/2022 54 54 13
14 1/4/2023 32 32 14
15 2/8/2023 48 48 15
16 2/15/2023 24 24 16
17 3/8/2023 28 28 17
18 4/5/2023 48 48 18
19 5/4/2023 27 27 19
20 6/7/2023 70 70 20
21 7/12/2023 40 40 21
22 8/9/2023 27 27 22
23 9/6/2023 47 47 23
24 10/4/2023 53 53 24
25 11/8/2023 63.9 63.9 25
26 12/6/2023 55.8 55.8 26
27 1/10/2024 46.7 46.7 27
28 2/7/2024 52.1 52.1 28
29 9/10/2019 35 35 29
30 10/7/2019 40 40 30
31 11/14/2019 45 45 31
32 12/5/2019 53 53 32
33 33
34 34
35 35
36 36
37 37
38 38
39 39
40 40
41 41
42 42
43 43
44 44
45 45
46 46
47 47
48 48
49 49
50 50
51 51
52 52
53 53
54 54
55 55
56 56
57 57
58 58
69841 RPA, data
-9- 5/31/2024

Crooked Creek WWTP #2 > Outfall 001
NCO069841 Freshwater RPA - 95% Probability/95% Confidence Using Metal Translators Qw = 1 .9 MGD
MAXIMUM DATA POINTS = 58
Qw (MGD) = 1.9000 WWTP/WTP Class: III COMBINED HARDNESS (mg/L)
1Q10S (cfs) = 0.00 IWC% @ 1Q10S = 100 Acute = 151.22 mg/L
7Q10S (cfs) = 0.00 IWC% @ 7Q10S = 100 Chronic= 151.22 mg/L
7Q10W (cfs) = 0.20 IWC% @ 7Q10W= 93.64069952
30Q2 (cfs) = 0.40 IWC% @ 30Q2 = 88.04185351
Avg. Stream Flow, QA(cfs) = 13.00 IW%C @ QA= 18.46973973
Receiving Stream: North Fork Crooked Creek HUC 03040105 Stream Class: C
PARAMETER NC STANDARDS OR EPA CRITERIA J H REASONABLE POTENTIAL RESULTS RECOMMENDED ACTION
CY
TYPE Aplied Chronic Standa d Acute D n # Det. Max Pred Cw Allowable Cw
Acute (FW): 340.0
Arsenic C 150 FW 340 ug/L _____
25 0 6.8 Chronic (FW) 150.0
-Max_MD_L= 10 --------- -----------------------------
Arsenic C 10 HH/WS ug/L NO DETECTS Chronic (HH) 54.1 No RP, Predicted Max< 50% of Allowable Cw- No
Max MDL- 10 Monitoring required
Acute: 65.00
Beryllium NC 6.5 FW 65 ug/L 4 0 6.48
Note: n< 9 C.V. (default) Chronic: 6.50 All non-detect< 5 ug/L - no monitoring required
Limited data set NO DETECTS Max MDL= 5
Acute: 15.960
Cadmium NC 3.8814 FW 15.9602 ug/L 25 1 113.420
--Chronic: -----3.881 --- ---------------------------
RP shown - apply Monthly Monitoring with Limit
1 values >Allowable Cw
Acute: NO WQS
Chlorides NC 230 FW mg/L 3 3 170.7
Note: n<_ 9 C.V. (default) Chronic: 230.0 No RP - limited datased, Max concentration < 25% of
Limited data set No value >Allowable Cw Allowable Cw- No Monitoring required
Acute: NO WQS
Total Phenolic Compounds NC 300 A ug/L 4 1 64.8
Note: n <_ 9 C.V. (default) Chronic: 340.7 No RP, Predicted Max< 50% of Allowable Cw- No
Limited data set No value > Allowable Cw Monitoring required
Acute: 3,952.6
Chromium III NC 514.1529 FW 3952.6066 µg/L 0 0 N/A
--Chronic: -----514.2--- ---------------------------
Acute: 16.0
Chromium VI NC I 1 FW 16 µg/L 0 0 N/A
--Chronic: ----- 11.0 --- ---------------------------
Tot Cr value(s) < 5 and< Cr VI Allowable Cw
Chromium, Total NC µg/L 25 4 3.1 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 Vl.
Acute: 57.09
Copper NC 36.6865 FW 57.0858 ug/L 32 32 13.89
Chronic: 36.69 No RP, Predicted Max< 50% of Allowable Cw- No
No value > Allowable Cw Monitoring required
Acute: 22.0
Cyanide NC 5 FW 22 10 ug/L 24 7 11.2
Chronic: 5.0 RP shown - apply Monthly Monitoring with Limit
2 values >Allowable Cw
69841 RPA, rpa
Page 1 of 2 5/31/2024

Crooked Creek WWTP #2 > Outfall 001
NCO069841 Freshwater RPA - 95% Probability/95% Confidence Using Metal Translators Qw = 1 .9 MGD
Acute: 549.240
Lead NC 21.4031 FW 549.2400 ug/L 25 1 7.500
Chronic: 21.403 No RP, Predicted Max< 50% of Allowable Cw- No
No value >Allowable Cw Monitoring required
Acute: NO WQS
Molybdenum NC 2000 HH ug/L 21 19 274.0
Chronic: 2,000.0 No RP, Predicted Max< 50% of Allowable Cw- No
No value > Allowable Cw Monitoring required
Acute (FW): 1,536.8
Nickel NC 170.6907 FW 1536.7966 µg/L _
25 22 45.2 Chronic (FW) 170.7 No RP, Predicted Max< 50% of Allowable Cw- No
No-value > Allowable Cw Monitoring required
Nickel NC 25.0000 WS µg/L Chronic (WS) 25.0
2 values >Allowable Cw
Acute: 56.0
Selenium NC 3.1 FW 56 ug/L 25 1 11.1
--Chronic: -----3-1--- ---------------------------
RP shown - apply Monthly Monitoring with Limit
7 values > Allowable Cw
Acute: 6.552
Silver NC 0.06 FW 6.5519 ug/L 39 0 3.000
Chronic: 0.060 All non-detect< 5 ug/L, < 1 ug/L and < 0.5 ug/L- no
NO DETECTS Max MDL= 5 monitoring required
Acute: 577.7
Zinc NC 582.3829 FW 577.6577 ug/L 32 32 87.2
Chronic: 582.4 No RP, Predicted Max< 50% of Allowable Cw- No
No value >Allowable Cw Monitoring required
Acute: NO WQS
Bis (2-ethylhexyl) phthalate C 0.37 HH µg/L 7 0 10.05000 _
Note: n< 9 C.V. (default) Chronic: 2.0 All non-detect< 10 ug/L and < 5 ug/L no monitoring
Limited data set NO DETECTS Max MDL= 10 required
69841 RPA, rpa
Page 2 of 2 5/31/2024

Permit No. NCO069841
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/l Chronic FW, µg/l Acute SW, µg/1 Chronic SW, µg/1
(Dissolved) (Dissolved) (Dissolved) (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
2B.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*{1.136672-[ln hardness](0.041838)} e^10.9151 [ln hardness]-3.1485}
Cadmium,Acute Trout waters WER*{1.136672-[ln hardness](0.041838)} e^{0.9151[In hardness]-3.62361
Cadmium,Chronic WER*{1.101672-[ln hardness](0.041838)} •e^{0.7998[ln hardness]-4.445 11
Chromium III,Acute WER*0.316 e^{0.8190[ln hardness]+3.7256}
Chromium III,Chronic WER*0.860 e^{0.8190[ln hardness]+0.6848}
Copper,Acute WER*0.960 e^{0.9422[ln hardness]-1.700}
Copper,Chronic WER*0.960 e^{0.8545[ln hardness]-1.702}
Lead,Acute WER*{1.46203-[ln hardness](0.145712)} • e^{1.273[ln hardness]-1.460}
Lead,Chronic WER*{1.46203-[ln hardness](0.145712)} •e^{1.273[ln hardness]-4.705)
Nickel,Acute WER*0.998 e^{0.8460[ln hardness]+2.255}
Nickel,Chronic WER*0.997 e^{0.8460[ln hardness]+0.0584}
Page 1 of 4

Permit No. NCO069841
Silver,Acute WER*0.85 •e^{1.72[ln hardness]-6.59}
Silver,Chronic Not applicable
Zinc,Acute WER*0.978 e^{0.8473[ln hardness]+0.884}
Zinc,Chronic WER*0.986 e^{0.8473[ln 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.
1. To perform a RPA on the Freshwater hardness-dependent metals the Permit Writer compiles the
following information:
• Critical low flow of the receiving stream, 7Q10(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. NCO069841
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)+s7Q10, cfs *Avg. Upstream Hardness,mg/L)
(Permitted Flow,cfs+s7Q10,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('+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. NC0069841
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.
8. 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) 151.22 Average from 912019 to 212024
[Total as, CaCO3 or(Ca+Mg)] samples
Average Upstream Hardness (mg/L) 25 Default value used
[Total as, CaCO3 or(Ca+Mg)]
7Q10 summer(cfs) 0 Historical;Previous Fact Sheet
1Q10(cfs) 0 Calculated in RPA
Permitted Flow(MGD) 1.9 MGD NPDES Files
Date: 5/31/2024
Permit Writer: Nick Coco
Page 4 of 4

NH3/TRC WLA Calculations
Facility: Crooked Creek WWTP#2
PermitNo. NC0069841
Prepared By: Nick Coco
Enter Design Flow (MGD): 1.9
Enter s7Q10 (cfs): 0
Enter w7Q10 (cfs): 0.2
Total Residual Chlorine (TRC) Ammonia (Summer)
Daily Maximum Limit (ug/1) Monthly Average Limit(mg NH3-N/1)
s7Q10 (CFS) 0 s7Q10 (CFS) 0
DESIGN FLOW (MGD) 1.9 DESIGN FLOW (MGD) 1.9
DESIGN FLOW (CFS) 2.945 DESIGN FLOW (CFS) 2.945
STREAM STD (UG/L) 17.0 STREAM STD (MG/L) 1.0
Upstream Bkgd (ug/1) 0 Upstream Bkgd (mg/1) 0.22
IWC (%) 100.00 IWC (%) 100.00
Allowable Conc. (ug/1) 17 Allowable Conc. (mg/1) 1.0
More restrictive than current limit.Apply Limit. Consistent with current limit.Maintain limit.
Ammonia (Winter)
Monthly Average Limit(mg NH3-N/1)
Fecal Coliform w7Q10 (CFS) 0.2
Monthly Average Limit: 200/100ml DESIGN FLOW (MGD) 1.9
(If DF >331; Monitor) DESIGN FLOW (CFS) 2.945
(If DF<331; Limit) STREAM STD (MG/L) 1.8
Dilution Factor(DF) 1.00 Upstream Bkgd (mg/1) 0.22
IWC (%) 93.64
Allowable Conc. (mg/1) 1.9
Consistent with current limit.Maintain limit.
Total Residual Chlorine
1. Cap Daily Max limit at 28 ug/l to protect for acute toxicity
Ammonia (as NH3-N)
1. If Allowable Conc > 35 mg/l, 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)

4/24/24 WQS= 12 ng/L MERCURY WQBEL/TBEL EVALUATION V:2013-6
Facility Name Crooked Creek WWTP#2/NC0069841 No Limit Required
/Permit No.
No MMP Required
Total Mercury 1631E PQL=0.5 ng/L 7Q10s = 0.000 cfs WQBEL= 12.00 ng/L
Date Modifier Data Entry Value Permitted Flow= 1.900 47 ng/L
5/6/20 0.83 0.83 0.8 ng/L-Annual Average for 2020
8/18/21 < 1 0.5 0.5 ng/L-Annual Average for 2021
7/21/22 3.91 3.91
8/18/22 1.63 1.63
9/15/22 2.45 2.45
10/12/22 < 1 0.5
11/2/22 < 0.08 0.5
12/7/22 1.39 1.39 1.7 ng/L-Annual Average for 2022
1/19/23 1.43 1.43
2/8/23 7.1 7.1
3/23/23 0.78 0.78
4/26/23 0.974 0.974
5/10/23 0.995 0.995
6/14/23 3.84 3.84
7/12/23 1.03 1.03
8/9/23 0.595 0.595
9/7/23 0.635 0.635
10/4/23 < 0.5 0.5
11/29/23 1.06 1.06
12/6/23 2.22 2.22 1.8 ng/L-Annual Average for 2023
1/24/24 0.788 0.788
2/8/24 1.47 1.47 1.1 ng/L-Annual Average for 2024

Crooked Creek WWTP#2/NC0069841
Mercury Data Statistics (Method 1631E)
2020 2021 2022 2023 2024
#of Samples 1 1 6 12 2
Annual Average, ng/L 0.8 0.5 1.7 1.76 1.129
Maximum Value, ng/L 0.83 0.50 3.91 7.1 1.47
TBEL, ng/L 47
WQBEL, ng/L 12.0

NCO069841 Crooked Creek WWTP #2 5/24/2024
BOD monthly removal rate TSS monthly removal rate
Month RR(%) Month RR(%) Month RR(%) Month RR(%)
September-19 99.50 March-22 99.00 September-19 99.49 March-22 98.96
October-19 99.22 April-22 98.53 October-19 99.49 April-22 98.04
November-19 99.32 May-22 99.11 November-19 99.51 May-22 99.66
December-19 99.15 June-22 98.93 December-19 99.45 June-22 98.89
January-20 98.89 July-22 99.27 January-20 98.82 July-22 98.95
February-20 98.82 August-22 99.36 February-20 98.80 August-22 99.33
March-20 99.06 September-22 99.16 March-20 99.08 September-22 98.99
April-20 98.90 October-22 99.13 April-20 98.58 October-22 99.22
May-20 98.82 November-22 99.16 May-20 98.93 November-22 99.43
June-20 99.00 December-22 98.96 June-20 99.16 December-22 98.08
July-20 98.94 January-23 97.92 July-20 99.50 January-23 90.08
August-20 98.99 February-23 97.96 August-20 99.42 February-23 96.32
September-20 99.09 March-23 98.91 September-20 99.52 March-23 98.39
October-20 98.44 April-23 98.88 October-20 98.59 April-23 98.77
November-20 99.03 May-23 98.98 November-20 99.41 May-23 99.15
December-20 99.27 June-23 99.06 December-20 99.54 June-23 98.93
January-21 99.06 July-23 98.87 January-21 99.52 July-23 99.41
February-21 98.66 August-23 98.75 February-21 98.12 August-23 99.37
March-21 99.22 September-23 98.68 March-21 99.60 September-23 99.24
April-21 99.16 October-23 99.06 April-21 99.25 October-23 99.40
May-21 99.16 November-23 99.08 May-21 99.38 November-23 98.87
June-21 99.06 December-23 98.16 June-21 98.43 December-23 94.34
July-21 99.11 January-24 98.61 July-21 99.16 January-24 98.33
August-21 98.83 February-24 98.83 August-21 99.19 February-24 99.10
September-21 99.04 March-24 September-21 99.28 March-24
October-21 99.23 April-24 October-21 99.35 April-24
November-21 99.24 May-24 November-21 98.45 May-24
December-21 98.27 June-24 December-21 99.32 June-24
January-22 98.20 July-24 January-22 97.33 July-24
February-22 98.97 August-24 February-22 99.17 August-24
Overall BOD removal rate 98.93 Overall TSS removal rate 98.74

MONITORING REPORT(MR)VIOLATIONS for: Report Date: 04/23/24 Page 1 of 1
Permit: NC006984 MRs Betweei 4 - 2019 and 4 - 2024 Region: % Violation Category:Limit Violation Program Category:
Facility Name:% Param Nam(% County: % Subbasin:% Violation Action:%
Major Minor: %
PERMIT: NCO069841 FACILITY: Union County-Crooked Creek WWTP#2 COUNTY: Union REGION: Mooresville
Limit Violation
MONITORING VIOLATION UNIT OF CALCULATED %
REPORT OUTFALL LOCATION PARAMETER DATE FREQUENCY MEASURE LIMIT VALUE Over VIOLATION TYPE VIOLATION ACTION
09-2019 001 Effluent pH 09/03/19 3 Xweek su 6 5.9 1.7 Daily Minimum Not No Action, Facility
Reached Reporting Error

Whole Effluent Toxicity Testing and Self Monitoring Summary
CooleemeeWWTP NCO024872/001 County: Davie Region: WSRO Basin: YAD06 Jan Apr Jul Oct SOC JOC:
Ceri7dPF Begin: 10/1/2021 CHR LIM:2.1% NonComp: SINGLE 7Q10: 106 PF: 1.5 IWC: 2.1 Freq: Q
J F M A M J J A S O N D
2020 Pass - - Pass - - Pass - - Pass - -
2021 Pass - - Pass - - Pass - - Pass - -
2022 Pass - - Pass - - Pass - - Pass - -
2023 Pass - - Pass - - Pass - - Pass - -
2024 Pass - - - - - - - - - - -
Craven Co.Wood Energy-001 NCO075281/001 County: Craven Region: WARO Basin: NEU08 Mar Jun Sep Dec SOC JOC:
Ceri7dPF Begin: 7/1/2008 Chr Lim:69%-rerout NonComp: Single 7Q10: 0.14 PF: 0.20 IWC: 69 Freq: Q
J F M A M J J A S O N D
2020 - - H - - H - - H - - H
2021 - - H - - H - - H - - H
2022 - - H - - H - - H - - H
2023 - - H - - H - - H - - H
Craven County NC WTP NCO089460/001 County: Craven Region: WARO Basin: NEU04 Jan Apr Jul Oct SOC JOC:
Mysd7dPF Begin: 6/1/2014 Mysid Limit:2% NonComp: 7Q10: PF: IWC: Freq: Q
J F M A M J J A S O N D
2020 Pass - - Pass - - Pass - - Pass - -
2021 Pass - - Pass - - INVALID Pass - Pass - -
2022 Pass - - Pass - - Pass - - Pass - -
2023 Pass - - Pass - - Pass - - Pass - -
2024 Pass - - - - - - - - - - -
Creswell WTP NCO027600/001 County: Washington Region: WARO Basin: PAS53 Feb May Aug Nov SOC JOC:
Fthd24PF Begin: 9/1/2018 Acu Fthd24hrPF Moni NonComp: 7Q10: 0 PF: 0.011 IWC: 100 Freq: Q
J F M A M J J A S O N D
2020 - Pass - - Pass - - Pass - - Pass -
2021 - Pass - - Pass - - Pass NR - - Pass -
2022 - Pass - - Pass - - Pass Pass - - Pass -
2023 - Pass - - Pass - - Pass NR - - INVALID INVALID
2024 Pass Pass - - - - - - - - - -
Crooked Creek WWTP#2 NCO069841/001 County: Union Region: MRO Basin: YAD14 Feb May Aug Nov SOC JOC:
Ceri7dPF Begin: 8/1/2018 chr lim:90% NonComp: Single 7Q10: 0.0 PF: 1.9 IWC: 100 Freq: Q
J F M A M J J A S O N D
2020 - Pass - - Pass - - >100(P)Pass - - Pass -
2021 - Pass - - Pass - - Pass - - Pass >100(P)
2022 - Pass INVALID >100(P) - Pass - - Pass - - Pass -
2023 - Pass - <22.5 Pass - - Pass - - Pass -
2024 - Pass - - - - - - - - - -
Leeend: P=Fathead minnow(Pimohales oromelas).H=No Flow(facilitv is active).s=Split test between Certified Labs Page 27 of 111

NORTH CAROLINA 2022 INTEGRATED REPORT
Rocky Yadkin-Pee Dee River Basin
AU Name AU Number Classification AU LengthArea AU Units
AU ID Description
Crooked Creek 13-17-20 C 12.9 FW Miles
2248 From source to Rocky River
2022 Water Quality Assessments
PARAMETER IR CATEGORY CRITERIA STATUS
Water Temperature (322C, AL, LP&CP) 1 Meeting Criteria
Dissolved Oxygen (4 mg/I, AL, FW) 1 Meeting Criteria
pH (6 su, AL, FW) 1 Meeting Criteria
pH (9.0, AL, FW) 1 Meeting Criteria
Turbidity (50 NTU, AL, FW miles) 3a Data Inconclusive
Benthos (Nar, AL, FW) 1 Meeting Criteria
Fish Community (Nar, AL, FW) 1 Meeting Criteria
Fecal Coliform (GM 200/400, REC, FW) 3a Data Inconclusive
North Fork Crooked Creek 13-17-20-1 C 12.0 FW Miles
2249 From source to Crooked Creek
2022 Water Quality Assessments
PARAMETER IR CATEGORY CRITERIA STATUS
Turbidity (50 NTU, AL, FW miles) 5 Exceeding Criteria
Water Temperature (322C, AL, LP&CP) 1 Meeting Criteria
Dissolved Oxygen (4 mg/I, AL, FW) 1 Meeting Criteria
pH (6 su, AL, FW) 1 Meeting Criteria
pH (9.0, AL, FW) 1 Meeting Criteria
Benthos (Nar, AL, FW) 5 Exceeding Criteria
Fecal Coliform (GM 200/400, REC, FW) 3a Data Inconclusive
6/7/2022 NC 2022 INTEGRATED REPORT-Category 5 Approved by EPA 4/30/2022 Page 1306 of 1346

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 NCO069841 I11 121 23/09/28 I17 18I� I 19 I G I 201 I
211IIIII 111111III II III III1 I I IIIII IIIIIIIII II r6
Inspection Work Days Facility Self-Monitoring Evaluation Rating B1 QA ----------------------Reserved-------------------
67 70LJ 71Ity 72 L-J 73 1 74 79 I I I I 80
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) 10:26AM 23/09/28 18/08/01
Crooked Creek WWTP#2
4015 Sardis Church Rd Exit Time/Date Permit Expiration Date
Monroe NC 28110 12:10PM 23/09/28 22/10/31
Name(s)of Onsite Representative(s)/Titles(s)/Phone and Fax Number(s) Other Facility Data
Rick Mareth/ORC/704-918-9678/
Name,Address of Responsible Official/Title/Phone and Fax Number
Contacted
Ralph B Sellers,PO Box 367 Wingate NC 28174//704-233-4042/
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 Compliance Schedules
Effluent/Receiving Wate 0 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
Roberto Scheller DWR/MRO WQ/707-235-2204/
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# 1

NPDES yr/mo/day Inspection Type 1
31 NCO069841 I11 12I 23/09/28 117 18 i c i
Section D: Summary of Finding/Comments (Attach additional sheets of narrative and checklists as necessary)
NPDES Permit#0069841 is for the continued operation of an existing 1.9 MGD wastewater treatment
facility that discharges into North Fork Crooked Creek which is classified as C waters in the Yadkin
Pee-Dee River Basin.
Page# 2

Permit: NCO069841 Owner-Facility: Crooked Creek WWTP#2
Inspection Date: 09/28/2023 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 0 ❑ ❑ ❑
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:
Operations & Maintenance Yes No NA NE
Is the plant generally clean with acceptable housekeeping? 0 ❑ ❑ ❑
Does the facility analyze process control parameters, for ex: MLSS, MCRT, Settleable ❑ ❑ ❑
Solids, pH, DO, Sludge Judge, and other that are applicable?
Comment:
Record Keeping Yes No NA NE
Are records kept and maintained as required by the permit? 0 ❑ ❑ ❑
Is all required information readily available, complete and current? 0 ❑ ❑ ❑
Are all records maintained for 3 years (lab. reg. required 5 years)? ■ ❑ ❑ ❑
Are analytical results consistent with data reported on DMRs? 0 ❑ ❑ ❑
Is the chain-of-custody complete? 0 ❑ ❑ ❑
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 M ❑ ❑ ❑
classification?
Page# 3

Permit: NCO069841 Owner-Facility: Crooked Creek WWTP#2
Inspection Date: 09/28/2023 Inspection Type: Compliance Evaluation
Record Keeping Yes No NA NE
Is a copy of the current NPDES permit available on site? 0 ❑ ❑ ❑
Facility has copy of previous year's Annual Report on file for review? 0 ❑ ❑ ❑
Comment: Copy of Annual Report was avaliable for review.
Influent Sampling Yes No NA NE
# Is composite sampling flow proportional? 0 ❑ ❑ ❑
Is sample collected above side streams? ■ ❑ ❑ ❑
Is proper volume collected? 0 ❑ ❑ ❑
Is the tubing clean? 0 ❑ ❑ ❑
# Is proper temperature set for sample storage (kept at less than or equal to 6.0 0 ❑ ❑ ❑
degrees Celsius)?
Is sampling performed according to the permit? 0 ❑ ❑ ❑
Comment: Infulent sampler recorded at 1.4 degrees Celsius at time of inspection.
Equalization Basins Yes No NA NE
Is the basin aerated? 0 ❑ ❑ ❑
Is the basin free of bypass lines or structures to the natural environment? ■ ❑ ❑ ❑
Is the basin free of excessive grease? 0 ❑ ❑ ❑
Are all pumps present? 0 ❑ ❑ ❑
Are all pumps operable? 0 ❑ ❑ ❑
Are float controls operable? ❑ ❑ ❑ ■
Are audible and visual alarms operable? ❑ ❑ ❑
# Is basin size/volume adequate? 0 ❑ ❑ ❑
Comment:
Chemical Feed Yes No NA NE
Is containment adequate? 0 ❑ ❑ ❑
Is storage adequate? 0 ❑ ❑ ❑
Are backup pumps available? N ❑ ❑ ❑
Is the site free of excessive leaking? 0 ❑ ❑ ❑
Comment: Liquid lime is being added for supplemental alkalinity at head of WWTP.
Bar Screens Yes No NA NE
Page# 4

Permit: NCO069841 Owner-Facility: Crooked Creek WWTP#2
Inspection Date: 09/28/2023 Inspection Type: Compliance Evaluation
Bar Screens Yes No NA NE
Type of bar screen
a.Manual ❑
b.Mechanical
Are the bars adequately screening debris? 0 ❑ ❑ ❑
Is the screen free of excessive debris? 0 ❑ ❑ ❑
Is disposal of screening in compliance? 0 ❑ ❑ ❑
Is the unit in good condition? 0 ❑ ❑ ❑
Comment:
Grit Removal Yes No NA NE
Type of grit removal
a.Manual ❑
b.Mechanical
Is the grit free of excessive organic matter? 0 ❑ ❑ ❑
Is the grit free of excessive odor? ■ ❑ ❑ ❑
# Is disposal of grit in compliance? 0 ❑ ❑ ❑
Comment: Debris from bar screen and grit are discharged into dumpster and disposed of at
conunty landfill.
Oxidation Ditches Yes No NA NE
Are the aerators operational? 0 ❑ ❑ ❑
Are the aerators free of excessive solids build up? 0 ❑ ❑ ❑
# Is the foam the proper color for the treatment process? ■ ❑ ❑ ❑
Does the foam cover less than 25% of the basin's surface? 0 ❑ ❑ ❑
Is the DO level acceptable? 0 ❑ ❑ ❑
Are settleometer results acceptable (> 30 minutes)? ❑ ❑ ❑
Is the DO level acceptable?(1.0 to 3.0 mg/I) ■ ❑ ❑ ❑
Are settelometer results acceptable?(400 to 800 ml/I in 30 minutes) ❑ ❑ ❑ ■
Comment: Oxidation ditches updated with new aerators.
Secondary Clarifier Yes No NA NE
Is the clarifier free of black and odorous wastewater? ■ ❑ ❑ ❑
Is the site free of excessive buildup of solids in center well of circular clarifier? 0 ❑ ❑ ❑
Are weirs level? M ❑ ❑ ❑
Page# 5

Permit: NC0069841 Owner-Facility: Crooked Creek WWTP#2
Inspection Date: 09/28/2023 Inspection Type: Compliance Evaluation
Secondary Clarifier Yes No NA NE
Is the site free of weir blockage? ■ ❑ ❑ ❑
Is the site free of evidence of short-circuiting? ■ ❑ ❑ ❑
Is scum removal adequate? ■ ❑ ❑ ❑
Is the site free of excessive floating sludge? ■ ❑ ❑ ❑
Is the drive unit operational? ■ ❑ ❑ ❑
Is the return rate acceptable (low turbulence)? ■ ❑ ❑ ❑
Is the overflow clear of excessive solids/pin floc? ■ ❑ ❑ ❑
Is the sludge blanket level acceptable? (Approximately '/4 of the sidewall depth) ❑ ❑ ❑ ■
Comment: Effluent from (4) secondary clarifiers was clear with few visible suspended soilds.
Pumps-RAS-WAS Yes No NA NE
Are pumps in place? ■ ❑ ❑ ❑
Are pumps operational? ■ ❑ ❑ ❑
Are there adequate spare parts and supplies on site? ❑ ❑ ❑ ■
Comment:
Filtration (High Rate Tertiary) Yes No NA NE
Type of operation: Down flow
Is the filter media present? ■ ❑ ❑ ❑
Is the filter surface free of clogging? ■ ❑ ❑ ❑
Is the filter free of growth? ■ ❑ ❑ ❑
Is the air scour operational? ■ ❑ ❑ ❑
Is the scouring acceptable? ❑ ❑ ❑ ■
Is the clear well free of excessive solids and filter media? ❑ ❑ ❑ ■
Comment:
Disinfection - UV Yes No NA NE
Are extra UV bulbs available on site? ❑ ❑ ❑ ■
Are UV bulbs clean? ■ ❑ ❑ ❑
Is UV intensity adequate? ■ ❑ ❑ ❑
Is transmittance at or above designed level? ■ ❑ ❑ ❑
Is there a backup system on site? ❑ ❑ ■ ❑
Is effluent clear and free of solids? ■ ❑ ❑ ❑
Page# 6

Permit: NCO069841 Owner-Facility: Crooked Creek WWTP#2
Inspection Date: 09/28/2023 Inspection Type: Compliance Evaluation
Disinfection - UV Yes No NA NE
Comment:
Effluent Sampling Yes No NA NE
Is composite sampling flow proportional? 0 ❑ ❑ ❑
Is sample collected below all treatment units? 0 ❑ ❑ ❑
Is proper volume collected? ■ ❑ ❑ ❑
Is the tubing clean? 0 ❑ ❑ ❑
# Is proper temperature set for sample storage (kept at less than or equal to 6.0 0 ❑ ❑ ❑
degrees Celsius)?
Is the facility sampling performed as required by the permit (frequency, sampling type 0 ❑ ❑ ❑
representative)?
Comment: At time of inspection effluent sampler was recorded at 3.1 Degrees Celsius.
Flow Measurement - Effluent Yes No NA NE
# Is flow meter used for reporting? 0 ❑ ❑ ❑
Is flow meter calibrated annually? 0 ❑ ❑ ❑
Is the flow meter operational? 0 ❑ ❑ ❑
(If units are separated) Does the chart recorder match the flow meter? 0 ❑ ❑ ❑
Comment: Flow meter calibrated on 8/1/2023.
Pump Station - Effluent Yes No NA NE
Is the pump wet well free of bypass lines or structures? 0 ❑ ❑ ❑
Are all pumps present? ❑ ❑ 0 ❑
Are all pumps operable? 0 ❑ ❑ ❑
Are float controls operable? M ❑ ❑ ❑
Is SCADA telemetry available and operational? 0 ❑ ❑ ❑
Is audible and visual alarm available and operational? ❑ ❑ ❑
Comment: 1 of 3 effluent pumps removed for repairs.
Compliance Schedules Yes No NA NE
Is there a compliance schedule for this facility? 0 ❑ ❑ ❑
Is the facility compliant with the permit and conditions for the review period? 0 ❑ ❑ ❑
Comment: Schedule of compliance for Ammonia - Nitorgen limits. Permittee achieved compliance
with NH3-N limitations specified in Section A. (2.) by January 31, 2022.
Page# 7

Permit: NC0069841 Owner-Facility: Crooked Creek WWTP#2
Inspection Date: 09/28/2023 Inspection Type: Compliance Evaluation
Compliance Schedules Yes No NA NE
Page# 8