NC0020656_Fact Sheet_20201217

Fact Sheet
NPDES Permit No. NCO020656
Permit Writer/Email Contact Nick Coco, [e-mail]:
Date: August 19, 2020
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:
City of Laurinburg/Leith Creek Wastewater Treatment Plant (WWTP)
Applicant Address:
PO Box 249, Laurinburg, NC 28353
Facility Address:
620 Hall Street, Laurinburg, NC 28353
Permitted Flow:
4.0 MGD
Facility Type/Waste:
MAJOR Municipal; 100% domestic
Facility Class:
Grade IV Biological Water Pollution Control System
Treatment Units:
Mechanical bar screen, Mechanical grit removal, Influent flow
monitoring, Influent pump station, Flow splitter box, Three aeration
Basins, Three secondary clarifiers, Chlorination/Dechlorination,
Effluent flow measurement, One aerobic digester, Effluent force main,
Cascade aeration, Standby generator
Pretreatment Program (Y/N)
N
County:
Scotland
Region
Fayetteville
Briefly describe the proposed permitting action and facility background. The City of Laurinburg has
applied for an NPDES permit renewal at 4.0 MGD for the Leith Creek WWTP. This facility serves a
population of 15,156 residents. Treated domestic wastewater is discharged into Big Shoe Heel Creek, a
class C;SW water in the Lumber River Basin. The facility has a primary Outfall 001.
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2. Receiving Waterbody Information:
Receiving Waterbody Information
Outfalls/Receiving Stream(s):
Outfall 001 - Big Shoe Heel Creek
Stream Index:
14-34
Stream Classification:
C-Sw
Drainage Area (m12):
83
Summer 7Q10 (cfs)
13.8
Winter 7Q10 (cfs):
24
30Q2 (cfs):
35
Average Flow (cfs):
95
IWC (% effluent):
31
303(d) listed/parameter:
No
Subject to TMDL/parameter:
Yes- State wide Mercury TMDL implementation.
Subbasin/HUC:
03-07-55/03040204
USGS Topo Quad:
H21 SW Laurinburg, NC
3. Effluent Data Summary
Effluent data for Outfall 001 is summarized below for the period of July 2016 through July 2020.
Table 1. Effluent Data Summary Outfall 001
Permit
Parameter
Units
Average
Max
Min
Limit
Flow
MGD
2.6
7.123
0.067
MA 4.0
WA 30.0
BOD
mg/1
2.4
9.4
2
MA 20.0
WA 45.0
TSS
mg/1
12.9
52
2 �
MA 30.0
WA 15.0
NH3N
mg/1
0.8
10.6
0.1
MA 5.0
DO
mg/1
8.3
9.9
5.1
DA > 5 mg/1
(geometric)
(ge
Fecal coliform
4/100 ml
798
0.1
WA 400
70.8
0.8
MA 200
Temperature
° C
20.2
27
9
Total Residual Chlorine
ug/1
25.9
49
7
DM 28
Conductivity
µmhos/cm
319
500
137
pH
SU
6.8
7.5
6
6.0 < pH <
9.0
Total Zinc
ug/1
76.4
275
24
Total Copper
ug/I
17.6
42
8
Total Mercury
ng/1
14.7
62
2.39
AA 39
TN
mg/1
9.7
32.7
1.2
TP
mg/1
2.3
6.53
0.067
MA -Monthly Average, WA -Weekly Average, DM -Daily Maximum, DA-Daily Average, QA-
Quarterly Average, AA -Annual Average
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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 dissolved oxygen, temperature,
conductivity and fecal coliform upstream of the outfall at least 100 feet, downstream (D 1) at NCSR 1612,
and downstream (D2) at NCSR 1108. Data was observed from July 2016 to June 2020. The data has been
summarized in Table 2 below.
Table 2. Instream Monitoring Data Summary
Parameter
Units
Upstream
Downstream 1
Downstream 2
Average
Max
Min
Average
Max
Min
Average
Max
Min
Conductivity
µmhos/cm
38.6
85
15
46.0
108
14
46.4
83
10
Fecal
Coliform
#/100 nil
(geomean)
392
3900
22
(geomean)
499
6000
3
1
(geomean)
600.7
4000
3
DO
mg/1
6.1
9.7
1.4
6.0
9.8
1.1
5.0
9.8
1.1
Temperature
° C
19.3
28
4
19.4
27
4
19.9
28
4
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
The downstream temperature did not exceed 32 degrees Celsius [per 15A NCAC 02B .0211 (18)]. The
temperature differential exceeded 2.8 degrees Celsius on one occasion between the upstream sample
location and both downstream sample locations D1 and D2 during the period reviewed. It was concluded
that no statistically significant difference exists between upstream and downstream temperature at both
downstream locations D 1 and D2.
Downstream DO at location D 1 dropped below 5 mg/L on 26 occasions [per 15A NCAC 02B .0211 (6)]
during the period reviewed. Downstream DO at location D2 dropped below 5 mg/L on 146 occasions
during the period reviewed. Downstream DO at location D1 dropped below 4 mg/L on 5 occasions during
the period reviewed. Downstream DO at location D2 dropped below 4 mg/L on 73 occasions during the
period reviewed. It was concluded that no statistically significant difference exists between upstream and
downstream DO at location D1. However, it was concluded that a statistically significant difference exists
between upstream and downstream DO at location D2. Effluent BOD did not show any spikes and
effluent DO was consistently above 5 mg/L during the period reviewed, suggesting that instream
dissolved oxygen is being influenced by factors outside of the wastewater treatment plant (the receiving
stream is classified as Swamp waters).
It was concluded that a statistically significant difference exists between upstream and downstream
conductivity at location D1 and between upstream and downstream conductivity at location D2. Effluent
conductivity was consistently higher than upstream conductivity during the review period and appears to
be influencing conductivity levels downstream. Instream and effluent conductivity monitoring will
continue to be a permit requirement.
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The geometric mean for fecal coliform exceeded 200/100mL upstream of the facility and at both
downstream locations D1 and D2 [per 15A NCAC 02B .0211 (7)] during the period reviewed. Fecal
coliform was reported at levels greater than 400/100ml in more than 20% of samples taken upstream and
at both downstream locations D1 and D2 during the period reviewed. It was concluded that a statistically
significant difference exists between upstream and downstream fecal coliform at location D1 and between
upstream and downstream fecal coliform at location D2. Effluent fecal coliform was consistently lower
than instream fecal coliform, suggesting that the facility's effluent is not negatively impacting fecal
coliform levels in the stream.
The draft permit proposes the removal of monitoring requirements for Downstream Location D1 (NCSR
1612). The Permittee shall continue to conduct monitoring upstream and downstream at NCSR 1108.
Is this facility a member of a Monitoring Coalition with waived instream monitoring (YIN): N
Name of Monitoring Coalition: NA
5. Compliance Summary
Summarize the compliance record with permit effluent limits (past 5 years): In 2018, the facility reported
2 fecal coliform limit violations and 1 flow limit violation resulting in enforcement. The facility reported
1 ammonia limit violation and 3 flow limit violations resulting in enforcement in 2019. In 2020, the
facility reported 1 flow limit violation resulting in enforcement.
Summarize the compliance record with aquatic toxicity test limits and any second species test results
(past 5 years): The facility passed 18 of 18 quarterly chronic toxicity tests as well as 4 of 4 second species
toxicity tests from February 2016 to May 2020.
Summarize the results from the most recent compliance inspection: The last facility inspection conducted
in June 2019 reported that the facility was compliant.
6. Water Quality -Based Effluent Limitations (WQBELs)
Dilution and MixingZones
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 I5A 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.
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If permit limits are more stringent than TBELs, describe how limits were developed.- The existing
limitations for BOD5 have been in the permit since at least 1987 and are based on modeling to protect
instream DO. 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.
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/1(acute impacts). Due to analytical issues, all TRC values
reported below 50 ug/1 are considered compliant with their permit limit.
Describe any proposed changes to ammonia and/or TRC limits for this permit renewal: The current
permit sets a daily maximum limit of 28 ug/L. TRC limits have been reviewed in the attached WLA and
have been found to be consistent with the results. There are no proposed changes for TRC.
Limitations for ammonia have been in the permit since at least 1987 and are based on modeling to protect
instream DO. The current permit sets monthly average and weekly average limits for ammonia of 5 mg/L
and 15 mg/L, respectively. The ammonia limits have been reviewed in the attached WLA. Based on
instream waste concentration -based calculations, ammonia limits are proposed to be set as monthly
average and weekly average limits of 2.7 mg/L and 8.1 mg/L, respectively.
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 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 August 2016
through August 2019. 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: Total Copper, Total Zinc
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: NA
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
Page 5 of 11

standards/criteria and the maximum predicted concentration was <50% of the allowable
concentration: NA
POTW Effluent Pollutant Scan Review: Three effluent pollutant scans were evaluated for
additional pollutants of concern. (PPAs from 2016, 2017 and 2018)
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: N/A
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: N/A
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
Arsenic, Total Phenolic Compounds, Beryllium, Total Cadmium, Total Chromium, Total
Cyanide, Total Lead, Total Nickel, Total Selenium, Total Silver
The City reported Total Silver and Total Cadmium at less than detection, with a detection level < 5 µg/L
and < 2 µg/L, respectively, in their effluent pollutant scans. The City's chronic allowable discharge
concentration is 0.194 µg/L for Total Silver and 1.903 µg/L for Total Cadmium. DWR's laboratory
identifies the target Practical Quantification Limits (PQL) as 1.0 µg/L for Total Silver and 0.5 µg/L for
Total Cadmium. 15A NCAC 2B .0505 (e) (4) requires that all test procedures must produce detection and
reporting levels that are below the permit discharge requirements. If no approved methods are capable of
achieving a detection level below the permit discharge requirement (or allowable concentration) the
method with the lowest detection level must be used. The City shall test for Total Silver and Total
Cadmium down to a PQL below the allowable discharge concentration. While no monitoring requirement
has been added to the permit for Total Silver or Total Cadmium at this time, the Division can add a limit
or add limits during the next renewal if this regulation is not satisfied.
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.
Toxici , 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: The permit requires quarterly chronic toxicity testing at
3 1 % effluent concentration. No changes are proposed.
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
Page 6 of 11

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 3. Mercury Effluent Data Summary (4.0 MGD)
2016
2017
2018
2019
2020
# of Samples
2
4
4
2
2
Annual Average Conc. n /L
33.3
14.2
3.2
11.15
23.36
Maximum Conc., n /L
62
20.3
3.78
11.9
38.7
TBEL, n /L
47
WQBEL, n /L
38.71
Describe proposed permit actions based on mercury evaluation: Since an individual mercury sample
exceeded the TBEL, the mercury limit is maintained. A mercury minimization plan (MMP) was
implemented in the current permit. Since the facility is > 2 MGD in design capacity and reported multiple
quantifiable levels of mercury (> 1 ng/1), the mercury minimization plan (MMP) will remain in the
permit.
Other TMDL/Nutrient Management Strategy Considerations
If applicable, describe any other TNDDLs/Nutrient Management Strategies and their implementation
within this permit: NA
Other WQBEL Considerations
If applicable, describe any other parameters of concern evaluated for WQBELs: NA
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: As total copper demonstrated
reasonable potential to exceed the facility's allowable discharge concentrations based on state surface
water standards, monthly average and daily maximum limits have been put in the permit. After discussing
the limits with the Permittee, the Permittee requested a schedule of compliance to provide time to locate
issues and come into compliance with the new limits. A 3-year compliance schedule has been put in the
permit. Within 1 year of the permit's effective date, the Permittee shall submit to DWR an Action Plan for
Division approval, summarizing the strategy or actions to be taken to achieve compliance with the total
copper limitations. Within 2 years of the permit's effective date, the Permittee shall submit a report to the
Division summarizing actions taken in accordance with the Action Plan. The City shall achieve
compliance with total copper limitations within 3 years of the permit's effective date. The plan will
include specific dates for completion or implementation of each action.
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
Page 7 of 11

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; Overall BOD and TSS
removal rates > 85%. It is recommended that the Permiee report to lower detection levels for TSS to
ensure accuracy of percent removal.
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 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
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.
The City of Laurinburg requested monitoring frequency reductions for BOD5, Total Suspended Solids,
NH3-N and Fecal Coliform on February 5, 2019 for their 2020 NPDES permit renewal based on DWR
Page 8 of 11

Guidance Regarding the Reduction of Monitoring Frequencies in NPDES Permits for Exceptionally
Performing Facilities. The last three years of the facility's data for these parameters have been reviewed
in accordance with the criteria outlined in the guidance. The Division has decided to grant the City
2/week monitoring frequency requirements for BOD5, Total Suspended Solids, NH3-N and Fecal
Coliform.
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 4.0 MGD
Parameter
Current Permit
Proposed Change
Basis for Condition/Change
Flow
MA 4.0 MGD
No change
15A NCAC 213 .0505
BOD5
MA 20.0 mg/1
No change to limits
WQBEL. 1987 model. 15A NCAC
WA 30.0 mg/l
2/week monitoring
213; DWR Guidance Regarding the
Reduction of Monitoring
Frequencies in NPDES Permits for
Exceptionally Performing
Facilities
NH3-N
MA 5.0 mg/l
MA 2.7 mg/l
WQBEL. 2020 WLA review. 15A
WA 15.0 mg/l
WA 8.1 mg/l
NCAC 213; DWR Guidance
2/week monitoring
Regarding the Reduction of
Monitoring Frequencies in NPDES
Permits for Exceptionally
Performing Facilities
TSS
MA 30 mg/l
No change to limits
TBEL. Secondary treatment
WA 45 mg/1
2/week monitoring
standards/40 CFR 133 / 15A
NCAC 213.0406; DWR Guidance
Regarding the Reduction of
Monitoring Frequencies in NPDES
Permits for Exceptionally
Performing Facilities
Fecal coliform
MA 200 /100ml
No change to limits
WQBEL. State WQ standard, 15A
WA 400 /100ml
2/week monitoring
NCAC 213; DWR Guidance
Regarding the Reduction of
Monitoring Frequencies in NPDES
Permits for Exceptionally
Performing Facilities
DO
DA > 5 mg/l
No change
WQBEL. State WQ standard, 15A
NCAC 2B .0200
Page 9 of 11

Temperature
Monitor and
No change
Surface Water Monitoring, 15A
Report Daily
NCAC 2B. 0500
pH
6 — 9 SU
No change
WQBEL. State WQ standard, 15A
NCAC 2B
Conductivity
Monitor and
No change
Surface Water Monitoring, 15A
Report Daily
NCAC 2B. 0500
Total Residual Chlorine
DM 28 ug/L
No change
WQBEL. 2020 WLA review.
Total Nitrogen
Monitor and
No change
Surface Water Monitoring, 15A
Report Monthly
NCAC 2B. 0500
Total Phosphorous
Monitor and
No change
Surface Water Monitoring, 15A
Report Monthly
NCAC 2B. 0500
Total Copper
Monitor and
MA 25.4 ug/1
Based on results of Reasonable
Report Quarterly
DM 29.7 ug/1
Potential Analysis (RPA); RP
shown - apply Monthly Monitoring
Monitor and Report
with Limit
Monthly
Total Zinc
Monitor and
MA 357.2 ug/1
Based on results of Reasonable
Report Quarterly
DM 357.2 ug/1
Potential Analysis (RPA); RP
shown - apply Monthly Monitoring
Monitor and Report
with Limit
Monthly
Total Mercury
AA 39 ng/L
No change
WQBEL. Consistent with 2012
Statewide Mercury TMDL
Implementation; individual
mercury sample exceeded the
TBEL
Total Hardness
No requirement
Quarterly monitoring
Hardness -dependent dissolved
Upstream and in
metals water quality standards
Effluent
approved in 2016
Chronic Toxicity
Chronic limit,
No change
WQBEL. No toxics in toxic
3 1 % effluent
amounts. 15A NCAC 2B
Effluent Pollutant Scan
Three times per
No change; conducted
40 CFR 122
permit cycle
in 2022, 2023, 2024
Instream Monitoring
Upstream (U),
Upstream (U) and
Surface Water Monitoring, 15A
Downstream at
Downstream at NCSR
NCAC 2B. 0500; 2020 Review of
NCSR 1612 (D1)
1108 (D)
instream monitoring data
and Downstream at
NCSR 1108 (D2)
Mercury Minimization
MMP Special
No change
WQBEL. Consistent with 2012
Plan (MMP)
Condition
Statewide Mercury TMDL
Implementation; Municipality with
Q > 2 MGD and with multiple
detects > 1 ng/L
Electronic Reporting
Electronic
No change
In accordance with EPA Electronic
Reporting Special
Reporting Rule 2015.
Condition
MGD — Million gallons per day, MA - Monthly Average, WA — Weekly Average, DM — Daily Max, QA
— Quarterly Average, DA — Daily Average, AA — Annual Average
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13. Public Notice Schedule:
Permit to Public Notice: September 11, 2020
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. Fact Sheet Addendum (if applicable):
The draft was submitted to the City of Laurinburg, EPA Region IV, and the Division's Fayetteville
Regional Office, Aquatic Toxicology Branch and Operator Certification Program for review. The Aquatic
Toxicology Branch submitted a comment to correct the mailing address specified in Special Condition
A.(2.). No comments were received from any of the other parties.
Were there any changes made since the Draft Permit was public noticed (Yes/No): YES
If Yes, list changes and their basis below:
• A notation was made concerning the Electronic Reporting Rule — Phase 2 Extension. extended
the Phase 2 deadline from December 21, 2020, to December 21, 2025, effective January 4, 2021.
The current compliance date has been extended to reflect this change.
• The expiration date has been extended from 2024 to 2025 to more closely fit a five-year permit
term.
• The Effluent Pollutant Scan sampling years have been adjusted to 2022, 2023 and 2024 to better
fit the extended permit term [See A. (3.)].
• The mailing address specified in Special Condition A. (2.) Chronic Toxicity Permit Limit
(Quarterly) has been updated.
15. Fact Sheet Attachments (if applicable):
• RPA Spreadsheet Summary
• BOD and TSS Removal
• Monitoring Reduction Frequency Spreadsheet
• Dissolved Metals Implementation/Freshwater
• Waste Load Allocation Spreadsheet
• Mercury TMDL Spreadsheet
• Limit Violations Summary
• Toxicity Summary
• Pretreatment Summary
• Instream Monitoring Summary
Page 11 of 11

AFFP
Public Notice North Carolina E
Affidavit of Publication
STATE OF NORTH SS
CAROLINA)
COUNTY OF SCOTLAND)
Sharon Taylor, being duly sworn, says:
That she is Legal Advertising Representative of the The
Laurinburg Exchange, a daily newspaper of general
circulation, printed and published in Laurinburg, Scotland
County, North Carolina; that the publication, a copy of
which is attached hereto, was published in the said
September 12, 2020
That said newspaper was regularly issued and circulated
on those dates.
SIGNED:
r.
13
Legal Advertising Represefilative
Subscribed to and sworn to me this 12th day of
September 2020.
7
2tb'
Amy Jo
Carolin,
n=;I�otary Pu
My commission a cpi re :
22041573 01011114
001%111111111) () fI f fili
�OHNSO
ONTA Pj k
blic, Scotlarib CDI. nt Cal h
IP
..
i
i t
July 29, 2020�- 0- VE *4
41VD C
Wren Thedford
425-NCQEQ-DWR
1617 Mail Service Center
Raleigh, NC 27699
Public Notice
North Carolina Environmental f anagernent Cornmission/NPDES Unit
1617 Mail Service Center
Raleigh, NC 27699-1617
Notice of latent to Issue a NPIDES Wastewater Permit O0 0 6 City Of
Laurinburg
The North Carolina Environmental Management Commission proposes to issue a
NPDES wastewater discharge permit to the person(s) listed below. Written
comments regarding the proposed permit will be accepted until 30 days after the
publish date of this notice. The Director of the NC Division of Water Resources
(DWR) may hold a public hearing should there be a significant degree of public
interest_ Please mail comments and/or information requests to DWR at the above
address. Interested persons may visit the DWR at 512 N. S@Iisbury Street, Raleigh,
NC to review information on file. Additional information on NPDES permits and this
Notice may be found on our wehsit : http-//deq. n .go /abouYdivisIons/ ater-
re our a /wat r-rn uu roes -perm its/ caste ate r-bran h/n pde - ate ateripu bI io-
n oti e , or by ca Ilin (9 1 ) 707-360 1. The City of La u rinbu rg has requested re ne ai
of permit NCO020656 for its Leith Creek WVVTP in Scotland County; this permitted
discharge is treated municipal wastewater to Big Shoe Heel Creek, in the Lumber
Fiver Basra

Attachment A —Request for Missing Information
Table 2. EPA Application Form zA Missing Information
1.1 Email address of facility contact: [e-mail]. [e-mail]
1.2 Applicant email address:dmedlin Iaurinbur .or
1.3 Email address of the organization transporting the discharge for treatment prior to discharge:dmedlin Iaurinbur .or
1.4 Email address of the organization receiving the discharge for treatment prior to discharge:dmedlin Iaurinbur .or
1.5 Do you intend to request or renew one or more of the variances authorized at 40 CFR 122.21(n)? (Check all that apply. Consult
with your NPDES permitting authority to determine what information needs to be submitted and when.)
Discharges into marine waters (CWA Section
El 301(h))
x Not applicable
Water quality related effluent limitation (CWA
Section 302(b)(2))
1.6 Emai1 address of contractor responsible for operational or maintenance aspects of the treatment works:
dmedlin Iaurinbur .or
i
1.7 Indicate the number of SIUs and NSCIUs that discharge to the POTW.
Number of SIUs Number of CIUs
N/A
1.8 1 Certification Statement
l certify under penalty of taw that this document and all attachments were prepared under my direction or supervision in
accordance with a system designed to assure that qualified personnel properly gather and evaluate the information submitted.
Based on my inquiry of the person or persons who manage the system, or those persons directly responsible for gathering the
information, the information submitted is, to the best of my knowledge and belief, true, accurate, and complete. 1 am aware that
there are significant penalties for submitting false information, including the possibility of fine and imprisonment for knowing
violations.
Name (print or type first and last name): Dixon Medlin I official title: Water Treatment Director
Signatur Date signed
-6 ZS Z

Coco, Nick A
From: Dixon Medlin <[e-mail]>
Sent: Wednesday, September 2, 2020 3:12 PM
To: Coco, Nick A
Cc: Montebello, Michael J; Brantley, Mark; Charles Nichols; Chuck Willis ([e-mail])
Subject: RE: [External] RE: NC0020656 Leith Creek WWTP Proposed Permit Changes
• rnal email. Do not click links or open attachments unless you verify. Send all suspicious email as an attachment to
ort.s am nc. ov AN& # AM
Nicholas,
I feel like we should do the compliance schedule for copper in the draft permit.
Thanks,
Dixon Medlin
Director Of Water & Wastewater Treatment Plants
603 Lauchwood DR
Laurinburg, NC 28352
910-291-1716
[e-mail]
From: Coco, Nick A [mailto:[e-mail]]
Sent: Tuesday, September 1, 2020 2:56 PM
To: Dixon Medlin <[e-mail]>
Cc: Montebello, Michael J<[e-mail]>; Brantley, Mark <[e-mail]>; Charles
Nichols <[e-mail]>; Chuck Willis ([e-mail]) <[e-mail]>
Subject: RE: [External] RE: NC0020656 Leith Creek WWTP Proposed Permit Changes
Hi Mr. Medlin,
The City will have a 30-day period of time to submit comments on the draft permit once it has gone out to public
comment. The main point I was hoping to address is the compliance schedule for total copper. I cannot put a compliance
schedule in a permit unless requested by a permittee along with some justification, so I just wanted to bring this to your
attention prior to sending the draft out for public comment. If the City does provide a request and justification prior to
my submitting the permit for public comment, I can include a compliance schedule in the draft permit.
Thanks,
Nicholas A. Coco, El
Engineer
NPDES Municipal Permitting Unit
NC DEQ/ Division of Water Resources/Water Quality Permitting
919 707-3609 office
919 707 9000 main office
[e-mail]
Physical Address: 512 North Salisbury St.,Raleigh, NC, 27604
Mailing Address: 1617 Mail Service Center, Raleigh, NC, 27699-1617

I'm working at home due to the State of Emergency and DWR policy for Covid-19. Thanks for being patient as we
try to stay safe.
**Email is preferred but 1 am available to talk by via Microsoft Teams**
Email correspondence to and from this address is subject to the
North Carolina Public Records Law and may be disclosed to third parties.
From: Dixon Medlin <[e-mail]>
Sent: Tuesday, September 1, 2020 2:52 PM
To: Coco, Nick A <[e-mail]>
Cc: Montebello, Michael J<[e-mail]>; Brantley, Mark <mark.bra [e-mail]>; Charles
Nichols <[e-mail]>; Chuck Willis ([e-mail]) <[e-mail]>
Subject: [External] RE: NC0020656 Leith Creek WWTP Proposed Permit Changes
External email. Do not click links or open attachments unless you verify. Send all suspicious email as an attachment to
ilport.spamPnc.gov-
Mr. Coco,
I will review, do I need to let you know of any concerns or questions before you send the draft permit?
Thanks,
Dixon Jledlin
Director Of Water & Wastewater Treatment Plants
603 Lauchwood DR
Laurinburg, NC 28352
910-291-1716
[e-mail]
From: Coco, Nick A [mailto:[e-mail]]
Sent: Tuesday, September 1, 2020 1:57 PM
To: Dixon Medlin <[e-mail]>
Cc: Montebello, Michael J<[e-mail]>; Brantley, Mark <mark.bra [e-mail]>
Subject: NC0020656 Leith Creek WWTP Proposed Permit Changes
Hi Mr. Medlin,
I hope all is well.
I havejust about finished drafting the renewal NPDES permit NC0020656 for the Leith Creek WWTP and wanted to bring
your attention to some of the changes to be made to the permit:
Based on the reasonable potential analysis (RPA) showing reasonable potential to violate state water quality
standards, total copper and total zinc limits have been added to the permit along with monthly monitoring.
Per the results of instream waste concentration (IWC)-based calculations for ammonia nitrogen, ammonia
nitrogen limits have been revised.

Based on NPDES guidance regarding the reduction of monitoring frequencies in NPDES permits for exceptionally
performing facilities, monitoring requirements for BODS, NH3-N, Total Suspended Solids and Fecal Coliform
have been reduced to twice per week.
The NC 2007-2014 Water Quality Standard (WQS) Triennial Review was approved by the NC Environmental
Management Committee (EMC) on November 13, 2014. The US EPA subsequently approved the WQS revisions
on April 6, 2016 with some exceptions. The NC Division of Water Resources NPDES Permitting Unit is required to
implement the new dissolved metal standards in all permits public noticed after April 6, 2016. The new
standards for most metals include acute standards. Further, the freshwater standards for several metals are
expressed as the dissolved form of the metals, and seven metals have hardness -dependent equations. As a
result, the NPDES Permitting Unit will need site -specific effluent hardness data and instream hardness data,
upstream of the discharge, for each facility monitoring these metals in order to calculate permit limitations.
Effluent hardness and instream hardness sampling, upstream of the discharge, have been added to the permit at
a monitoring frequency of quarterly.
These changes will also be noted on the cover letter to your draft permit, but I wanted to just make you aware of the
changes ahead of time, in case there were any arrangements you wanted to get ahead of.
Regarding the limits, upon request and justification, Permittees may be granted Schedules of Compliance for newly
added limits in their permits. I bring this up because, while no sample was reported as being detected higher than the
allowable discharge concentration for total zinc, the Leith Creek WWTP did report multiple copper samples detected at
levels higher than the parameter's allowable discharge concentration. If you wish to have a compliance schedule, please
let me know. If you believe you know from where your facility is receiving copper and that you will be able to achieve
compliance with your permit limits upon the effective date of the permit, we can skip the compliance schedule. I do not
believe a compliance schedule would be necessary for total zinc, as the plant did not report values exceeding the
allowable discharge concentration. I also do not believe a compliance schedule would be necessary for the changes to
ammonia limits based on analysis of the last 4.5 years of ammonia data from the Leith Creek WWTP.
Summary of data and proposed limits
Parameter
Maximum Reported
Maximum Predicted
Allowable
RPA Analysis Decision
Concentration
Concentration
Discharge
Concentration
Total Zinc
275 ug/L
492.3 ug/L
MA 357.2 ug/L
RP shown - apply Monthly
DM 357.2 ug/L
Monitoring with Limit
Total Copper
42 ug/L
66.78 ug/L
MA 25.42 ug/L
RP shown - apply Monthly
DM 29.76 ug/L
Monitoring with Limit
Parameter
Current Permit
Proposed Change
NH3-N
MA 5.0 mg/I
MA 2.7 mg/I
WA 15.0 mg/I
WA 8.1 mg/I
2/week monitoring
Let me know what you think, whenever you get the chance.
Best,
Nicholas A. Coco, El
Engineer
NPDES Municipal Permitting Unit
NC DEQ/ Division of Water Resources/Water Quality Permitting
919 707-3609 office
919 707 9000 main office
[e-mail]

Physical Address: 512 North Salisbury St.,Raleigh, NC, 27604
Mailing Address: 1617 Mail Service Center, Raleigh, NC, 27699-1617
I'm working at home due to the State of Emergency and DWR policy for Covid-19. Thanks for being patient as we
try to stay safe.
**Email is preferred but 1 am available to talk by via Microsoft Teams**
b.0 .. - .. -IOMWWg CUCARres'k.-
Email correspondence to and from this address is subject to the
North Carolina Public Records Law and may be disclosed to third parties.

Freshwater RPA - 95% Probability/95% Confidence Using Metal Translators
MAXIMUM DATA POINTS = 58
Table 1. Project Information
❑ CHECK IF HQW OR ORW WQS
Facility Name
WWTP/WTP Class
NPDES Permit
Outfall
Flow, Qw (MGD)
Receiving Stream
HUC Number
Stream Class
Leith Creek WWTP
IV
NCO020656
001
4.000
Big Shoe Heel Creek
03040204
C-Sw
❑ Apply WS Hardness WQC
7Q10s (cfs)
7Q10w (cfs)
30Q2 (cfs)
QA (cfs)
1 Q10s (cfs)
13.800
24.00
35.00
95.00
11.42
Effluent Hardness
Upstream Hardness
Combined Hardness Chronic
Combined Hardness Acute
25 mg/L (Avg)
25 mg/L (Avg)
25 m /L
25 m /L
Data Source(s)
❑ CHECK TO APPLY MODEL
REQUIRED DATA ENTRY
Par01
Par02
Par03
Par04
Par05
Par06E
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
0.5899
FW
3.2396
ug/L
Chlorides
Aquatic Life
NC
230
FW
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
117.7325
FW
905.0818
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
7.8806
FW
10.4720
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
2.9416
FW
75.4871
ug/L
Mercury
Aquatic Life
NC
12
FW
0.5
ng/L
Molybdenum
Human Health
NC
2000
HH
ug/L
Nickel
Aquatic Life
NC
37.2313
FW
335.2087
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
0.2964
ug/L
Zinc
Aquatic Life
NC
126.7335
FW
125.7052
ug/L
20656 RPA, input
9/2/2020

REASONABLE POTENTIAL ANALYSIS
20656 RPA, data
- 1 - 9/2/2020

Par01 & Par02
Date Data
1 8/9/2016 <
2 11 /14/2017 <
3 2/13/2018 <
4
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
Arsenic
BDL=1/2DL
10 5
10 5
10 5
REASONABLE POTENTIAL ANALYSIS
Results
Std Dev.
Mean
C.V. (default)
n
Mult Factor =
Max. Value
Max. Pred Cw
Use "PASTE SPECIAL
Values" then "COPY"
Maximum data
points = 58
0.0000
5.0000
0.6000
3
3.00
5.0 ug/L
15.0 ug/L
-2-
20656 RPA, data
9/2/2020

Par03
Date Data
1 8/9/2016 <
2 11 /14/2017 <
3 2/13/2018 <
4
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
REASONABLE POTENTIAL ANALYSIS
Par04
Use "PASTE SPECIAL
Use "PASTE SPECIAL
Beryllium
Values" then "COPY"
Cadmium
Values" then "COPY"
Maximum data
. Maximum data
points = 58
points = 58
BDL=1/2DL
Results
Date Data
BDL=1/2DL
Results
2 1
Std Dev.
0.0000
1
8/9/2016 <
2 1
Std Dev.
0.0000
2 1
Mean
1.0000
2
11/14/2017 <
2 1
Mean
1.0000
2 1
C.V. (default)
0.6000
3
2/13/2018 <
2 1
C.V. (default)
0.6000
n
3
4
n
3
5
Mult Factor =
3.00
6
Mult Factor =
3.00
Max. Value
1.00 ug/L
7
Max. Value
1.000 ug/L
Max. Pred Cw
3.00 ug/L
8
Max. Pred Cw
3.000 ug/L
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
-3-
20656 RPA, data
9/2/2020

Par07
REASONABLE POTENTIAL ANALYSIS
Total Phenolic Compounds
Date Data
1 8/9/2016 <
2 11 /14/2017 <
3 2/13/2018 <
4
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
BDL=1/2DL
Results
40 20
Std Dev.
40 20
Mean
40 20
C.V. (default)
n
Mult Factor =
Max. Value
Max. Pred Cw
Use "PASTE SPECIAL
Values" then "COPY"
Maximum data
points = 58
Parl0
1
Date
8/9/2016
Chromium, Total
Data BDL=1/2DL
< 10 5
Results
Std Dev.
Use "PASTE SPECIAL
Values" then "COPY"
. Maximum data
points = 58
0.0000
0.0000
20.0000
2
11/14/2017
< 10 5
Mean
5.0000
0.6000
3
2/13/2018
< 10 5
C.V. (default)
0.6000
3
4
n
3
5
3.00
6
Mult Factor =
3.00
20.0 ug/L
7
Max. Value
5.0 pg/L
60.0 ug/L
8
Max. Pred Cw
15.0 pg/L
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
20656 RPA, data
-4- 9/2/2020

Pal
Date U
1 8/9/2016
2 11 /8/2016
3 2/14/2017
4 5/9/2017
5 8/15/2017 <
6 11/14/2017
7 2/13/2018 <
8 5/15/2018
9 8/14/2018
10 11 /6/2018
11 2/11/2019
12 3/27/2019
13 5/20/2019 <
14 8/14/2019
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
REASONABLE POTENTIAL ANALYSIS
Par12
Use "PASTE SPECIAL
Use "PASTE SPECIAL
Copper
pp
Values" then "COPY"
yan
Cyanide
Values" then "COPY"
. Maximum data
. Maximum data
points = 58
points = 58
BDL=1/2DL
Results
Date Data
BDL=1/2DL
Results
8
8
Std Dev.
10.7490
1
8/9/2016 <
5 5
Std Dev.
0.0000
15.6
15.6
Mean
16.5429
2
11/14/2017 <
5 5
Mean
5.00
14
14
C.V.
0.6498
3
2/13/2018 <
5 5
C.V. (default)
0.6000
22
22
n
14
4
n
3
10
5
5
26
26
Mult Factor =
1.59
6
Mult Factor =
3.00
10
5
Max. Value
42.00 ug/L
7
Max. Value
5.0 ug/L
11
11
Max. Pred Cw
66.78 ug/L
8
Max. Pred Cw
15.0 ug/L
14
14
9
29
29
10
12
12
11
23
23
12
10
5
13
42
42
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
20656 RPA, data
-5- 9/2/2020

Par14
Date
1 8/9/2016 <
2 11 /14/2017 <
3 2/13/2018 <
4
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
REASONABLE POTENTIAL ANALYSIS
Par17 & Par18
Use "PASTE
Use "PASTE SPECIAL
SPECIAL -Values"
Lead
Values" then "COPY"
Nickel
then "COPY".
. Maximum data
Maximum data
points = 58
points = 58
BDL=1/2DL
Results
Date Data
BDL=1/2DL
Results
5 2.5
Std Dev.
0.0000
1
8/9/2016 <
10 5
Std Dev.
0.0000
5 2.5
Mean
2.5000
2
11/14/2017 <
10 5
Mean
5.0000
5 2.5
C.V. (default)
0.6000
3
2/13/2018 <
10 5
C.V. (default)
0.6000
n
3
4
n
3
5
Mult Factor =
3.00
6
Mult Factor =
3.00
Max. Value
2.500 ug/L
7
Max. Value
5.0 pg/L
Max. Pred Cw
7.500 ug/L
8
Max. Pred Cw
15.0 pg/L
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
20656 RPA, data
9/2/2020

Parl9
Date Data
1 8/9/2016 <
2 11 /14/2017 <
3 2/13/2018 <
4
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
REASONABLE POTENTIAL ANALYSIS
Use "PASTE
Par20
SPECIAL -Values"
Use "PASTE SPECIAL -
Selenium
then "COPY".
Silver
Values" then "COPY".
Maximum data
Maximum data points =
points = 58
58
BDL=1/2DL
Results
Date Data
BDL=1/2DL
Results
10 5
Std Dev.
0.0000
1
8/9/2016 <
5 2.5
Std Dev.
0.0000
10 5
Mean
5.0000
2
11/14/2017 <
5 2.5
Mean
2.5000
10 5
C.V. (default)
0.6000
3
2/13/2018 <
5 2.5
C.V. (default)
0.6000
n
3
4
n
3
5
Mult Factor =
3.00
6
Mult Factor =
3.00
Max. Value
5.0 ug/L
7
Max. Value
2.500 ug/L
Max. Pred Cw
15.0 ug/L
8
Max. Pred Cw
7.500 ug/L
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
20656 RPA, data
-7- 9/2/2020

REASONABLE POTENTIAL ANALYSIS
Par21
Use "PASTE SPECIAL
Zinc
Values" then "COPY"
Maximum data
points = 58
Date
Data
BDL=1/2DL
Results
1
8/9/2016
46
46
Std Dev.
66.6295
2
11/8/2016
109
109
Mean
76.5714
3
2/14/2017
60
60
C.V.
0.8702
4
5/9/2017
130
130
n
14
5
8/15/2017
46
46
6
11/14/2017
125
125
Mult Factor =
1.79
7
2/13/2018
42
42
Max. Value
275.0 ug/L
8
5/15/2018
45
45
Max. Pred Cw
492.3 ug/L
9
8/14/2018
44
44
10
11 /6/2018
51
51
11
2/11 /2019
24
24
12
3/27/2019
48
48
13
5/20/2019
27
27
14
8/14/2019
275
275
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
20656 RPA, data
- 8 - 9/2/2020

Leith Creek WWTP
NCO020656 Freshwater RPA - 95% Probability/95% Confidence Using Metal Translators
MAXIMUM DATA POINTS = 58
Qw (MGD) =
4.0000
WWTP/WTP Class:
IV
1Ql0S (cfs) =
11.42
IWC% @ 1Ql0S =
35.18728717
7Q10S (cfs) =
13.80
IWC% @ 7Q10S =
31
7QIOW (cfs) =
24.00
IWC% @ 7Q10W =
20.52980132
30Q2 (cfs) =
35.00
1WC% @ 30Q2 =
15.04854369
Avg. Stream Flow, QA (cfs) =
95.00
IW%C @ QA =
6.126482213
Receiving Stream:
Big Shoe Heel Creek HUC 03040204
Stream Class:
C-Sw
Outfall 001
Qw = 4 MGD
COMBINED HARDNESS (mg/L)
Acute = 25 mg/L
Chronic = 25 mg/L
PARAMETER
NC STANDARDS OR EPA CRITERIA
co
REASONABLE POTENTIAL RESULTS
RECOMMENDED ACTION
TYPE
J
Chronic Standard Acute
n # Det. Max Pred Cw Allowable Cw
Acute (FW): 966.3
Arsenic
C
150 FW(7Q10s) 340
ug/L
-----------------------------------------------
3 0
15.0
Chronic (FW): 483.9
C.V. (default)
M_ax_MDL = 10
Arsenic
C
10 HH/WS(Qavg)
ug/L
Note: n < 9
NO DETECTS
Chronic (HH) 163.2
No RP, Predicted Max < 50% of Allowable Cw - No
Limited data set
Max MDL = 10
Monitoring required
Acute: 184.73
Beryllium
NC
6.5 FW(7QlOs) 65
ug/L
3 0
3.00
___ _ ____
Note: n < 9
C.V. (default)
Chronic: 20.97
No RP, Predicted Max < 50% of Allowable Cw - No
Limited data set
NO DETECTS
Max MDL = 2
Monitoring required
Acute: 9.207
Cadmium
NC
0.5899 FW(7Q 1 Os) 3.2396
ug/L
3 0
3.000
Note: n < 9
C.V. (default)
_ _ _ _ _ _ _ _ _ _ _ _ _ _
Chronic: 1.903
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _
All values reported non -detect < 2 ug/L - No
monitoring required. Permittee shall report to PQL of
Limited data set
NO DETECTS
Max MDL = 2
1 ug/L.
Acute: NO WQS
Total Phenolic Compounds
NC
300 A(30Q2)
ug/L
3 0
60.0
Note: n < 9
C.V. (default)
_ _ _ _ _ _ _ _ _ _ _ _
Chronic: 1,993.5
_ _ _ _ _ _ _ _ _ _ _ _ _
No RP, Predicted Max < 50% of Allowable Cw - No
Limited data set
NO DETECTS
Max MDL = 40
Monitoring required
Acute: 2,572.2
Chromium III
NC
117.7325 FW(7QlOs) 905.0818
µg/L
0 0
N/A
--Chronic:-----379.8---
---------------------------
Acute: 45.5
Chromium VI
NC
11 FW(7QlOs) 16
µg/L
0 0
N/A
--Chronic: ----- 35.5 ---
---------------------------
Chromium, Total
NC
µg/L
3 0
15.0
Max reported value = 5
a: No monitoring required if all Total Chromium
samples are < 5 pg/L or Pred. max for Total Cr is <
Note: n < 9
C.V. (default)
allowable Cw for Cr VI.
Limited data set
NO DETECTS
Max MDL = 10
Acute: 29.76
Copper
NC
7.8806 FW(7Q1 Os) 10.4720
ug/L
14 11
66.78
--Chronic:-----25_
---------------------------
42---
RP shown - apply Monthly Monitoring with Limit
3 values > Allowable Cw
Acute: 62.5
Cyanide
NC
5 FW(7QlOs) 22
10
ug/L
3 0
15.0
___ _ ______ ____
_ _ _ _ _ _ _ _ _ _ _ _ _
Note: n < 9
C.V. (default)
Chronic: 16.1
All values reported < 5 ug/L - No monitoring required
Limited data set
NO DETECTS
Max MDL = 10
Page 1 of 2
20656 RPA, rpa
9/2/2020

Leith Creek WWTP
NCOO2O656
Freshwater RPA - 95% Probability/95% Confidence Using Metal Translators
Outfall 001
Qw = 4 MGD
Acute: 214.529
Lead
NC
2.9416 FW(7Q1 Os) 75.4871
ug/L
3 0
7.500
Note: n < 9
C.V. (default)
_ _ _ _ _ _ _ _ _ _ _ _ _ _
Chronic: 9.489
_ _ _ _ _ _ _ _ _ _ _ _ _
All values reported < 5 ug/L - No monitoring required
Limited data set
NO DETECTS
Max MDL = 5
Acute (FW): 952.6
Nickel
NC
37.2313 FW(7QlOs) 335.2087
µg/L
3 0
15.0
_ _ _ _____ ____
Chronic (FW)120.1
___________________________
Note: n < 9
C.V. (default)
Max MDL = 10
Nickel
NC
25.0000 WS(7Q10s)
µg/L
Limited data set
NO DETECTS
Chronic (WS) 80.6
No RP, Predicted Max < 50% of Allowable Cw - No
Max MDL = 10
Monitoring required
Acute: 159.1
Selenium
NC
5 FW(7QlOs) 56
ug/L
3 0
15.0
Note: n < 9
C.V. (default)
___ _ ______ ____
Chronic: 16.1
___________________________
All values non -detect < 10 ug/L - No monitoring
Limited data set
NO DETECTS
Max MDL = 10
required
Acute: 0.842
Silver
NC
0.06 FW(7Q10s) 0.2964
ug/L
3 0
7.500
Note: n < 9
' —
C.V. (default)
Chronic: 0.194
All values reported non -detect < 5 ug/L - No
monitoring required. Permittee shall report to PQL of
Limited data set
NO DETECTS
Max MDL = 5
1 ug/L.
Acute: 357.2
RP shown - apply Monthly Monitoring with Limit
Zinc
NC
126.7335 FW(7QlOs) 125.7052
ug/L
14 14
492.3
- - - - _ _
-----
Chronic:-408.8
- - - - - - - - - - - - - - - - - - - - - - - - - - -
No value > Allowable Cw
20656 RPA, rpa
Page 2 of 2 9/2/2020

Permit No. NC0020656
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
(Dissolved)
Chronic FW, µg/1
(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:
FW= Freshwater, SW= Saltwater
Calculation = Hardness dependent standard
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/l 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* 11.136672-[ln hardness](0.041838)} eA10.9151 [In hardness]-3.1485}
Cadmium, Acute Trout waters
WER* {1.136672-[ln hardness](0.041838)} of 0.9151[In hardness]-3.6236}
Cadmium, Chronic
WER* {1.101672-[ln hardness](0.041838)} e^{0.7998[ln hardness]-4.4451}
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]-1.7001
Copper, Chronic
WER*0.960 e^{0.8545[In hardness]-1.7021
Lead, Acute
WER*{1.46203-[ln hardness](0.145712)1 • of 1.273[ln hardness]-1.4601
Lead, Chronic
WER* {1.46203-[ln hardness](0.145712)1 • of 1.273[ln hardness]-4.705}
Nickel, Acute
WER*0.998 e^{0.8460[ln hardness]+2.255}
Nickel, Chronic
WER*0.997 e-10.8460[ln hardness]+0.0584}
Page 1 of 4

Permit No. NCO020656
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]+0.8841
Zinc, Chronic
WER*0.986 e-10.8473[ln hardness]+0.8841
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
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. NCO020656
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 1Q10 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 - I
Ctotal I + f [Kpo] [ss(i+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 (le. 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 = (s7Q10 + Qw) (Cwgs) - (s7Q10) (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 s7Q10)
s7Q10 = 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 s7Q10 may be incorporated as applicable:
IQ10 = used in the equation to protect aquatic life from acute toxicity
Page 3 of 4

Permit No. NC0020656
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
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)]
25
Default Value used, 2016, 2017 and
2018 PPAs reported < 30 ug/L
Average Upstream Hardness (mg/L)
[Total as, CaCO3 or (Ca+Mg)]
25
Default Value used, No upstream
hardness reported
7Q 10 summer (cfs)
13.8
NPDES Files
1Q10 (cfs)
11.42
Calculated in RPA
Permitted Flow (MGD)
4.0
NPDES Files
Date: 8/21/2020
Permit Writer: Nick Coco
Page 4 of 4

Reduction in Frequency Evalaution
Facility:
Leith Creek WWTP
Permit No.
NC0020656
Review period (use
6/2017 - 6/2020
3 yrs)
Approval Criteria: Y/N?
1. Not currently under SOS
Y
2. Not on EPA Quarterly noncompliance
report
Y
3. Facility or employees convicted of CWA
violations
N
# of non -
Weekly
Monthly
3-yr mean
# daily
# daily
Reduce
50%
200%
200%
monthly
# civil penalty
Data Review
Units
average
average
(geo mean
< 50%?
samples
<15?
samples
< 20?
limit
> 2?
> 1?
Frequency?
limit
limit
MA
for FC)
MA
>200%
WA
>200%
asessment
(Yes/No)
violations
BOD
mg/L
30
20
10
1.6074627
Y
40
0
Y
0
N
0
N
Y
TSS
mg/L
45
30
15
6.4839838
Y
60
0
Y
0
N
0
N
Y
Ammonia
mg/L
15
5
2.5
0.5663744
Y
10
0
Y
1
N
1
N
Y
Fecal Coliform
#/100
400
200
1001
90.95968
Y
800 1 0 1 Y
0
N
0
N
Y

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NH3/TRC WLA Calculations
Facility: Leith Creek WWTP
PermitNo. NC0020656
Prepared By: Nick Coco
Enter Design Flow (MGD): 4
Enter s7Q10 (cfs): 13.8
Enter w7Q10 (cfs): 24
Total Residual Chlorine (TRC)
Daily Maximum Limit (ug/1)
Ammonia (Summer)
Monthly Average Limit (mg NH3-N/1)
s7Q10 (CFS)
13.8
s7Q10 (CFS)
13.8
DESIGN FLOW (MGD)
4
DESIGN FLOW (MGD)
4
DESIGN FLOW (CFS)
6.2
DESIGN FLOW (CFS)
6.2
STREAM STD (UG/L)
17.0
STREAM STD (MG/L)
1.0
Upstream Bkgd (ug/1)
0
Upstream Bkgd (mg/1)
0.22
IWC (%)
31.00
IWC (%)
31.00
Allowable Conc. (ug/1)
55
Allowable Conc. (mg/1)
2.7
Capped at 28 ug/L. Maintain limit.
More stringent than current
permit limit. Apply limit.
Ammonia (Winter)
Monthly Average Limit (mg NH3-N/1)
Fecal Coliform
w7Q10 (CFS)
24
Monthly Average Limit:
2001100- DESIGN FLOW (MGD)
4
(If DF >331; Monitor)
DESIGN FLOW (CFS)
6.2
(If DF<331; Limit)
STREAM STD (MG/L)
1.8
Dilution Factor (DF)
3.23 Upstream Bkgd (mg/1)
0.22
IWC (%)
20.53
Allowable Conc. (mg/1)
7.9
Summer limits applied
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/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)

9/2/20 WQS = 12 ng/L
Facility Name
Leith Creek WWTP/NC0020656
/Permit No.:
Total Mercury 1631E PQL = 0.5 ng/L
Date Modifier Data Entry Value
MERCURY WQBEL/TBEL EVALUATION V:2013-6
Annual Limit 39 ng/L with
Quarterly Monitoring
MMP Required
7Q10s = 13.800 cfs WQBEL = 38.71 ng/L
Permitted Flow = 4.000 47 ng/L
8/9/16
4.53
4.53
11/8/16
62
62
> TBEL 33.3 ng/L -
Annual Average for 2016
2/14/17
16.2
16.2
5/9/17
20.3
20.3
8/15/17
4.63
4.63
11/14/17
15.8
15.8
14.2 ng/L -
Annual Average for 2017
2/13/18
2.79
2.79
5/15/18
2.39
2.39
8/14/18
3.69
3.69
11/13/18
3.78
3.78
3.2 ng/L -
Annual Average for 2018
2/11/19
10.4
10.4
5/15/19
11.9
11.9
11.2 ng/L -
Annual Average for 2019
2/25/20
38.7
38.7
5/7/20
8.02
8.02
23.4 ng/L -
Annual Average for 2020

Leith Creek WWTP/NC0020656
Mercury Data Statistics (Method 1631E)
2016
2017
2018
2019
# of Samples
2
4
4
2
Annual Average, ng/L
33.3
14.2
3.2
11.15
Maximum Value, ng/L
62.00
20.30
3.78
11.9
TBEL, ng/L
47
WQBEL, ng/L
38.7
2020
23.36
38.7

MONITORING REPORT(MR) VIOLATIONS for:
Permit: NCO020656 MRS Betweel 7 - 2016 and 7 - 2020 Region: %
Facility Name:% Param Name% County: %
Major Minor: %
Report Date: 08/20/2C Page 24 of 25
Violation Category:Limit Violation Program Category: %
Subbasin:% Violation Action: %
PERMIT: NCO020656
FACILITY: City of Laurinburg -Leith Creek WWTP
COUNTY: Scotland
REGION: Fayetteville
Limit Violation
MONITORING
VIOLATION
UNIT OF
CALCULATED
%
REPORT
OUTFALL
LOCATION
PARAMETER
DATE
FREQUENCY
MEASURE
LIMIT
VALUE
Over
VIOLATION TYPE
VIOLATION ACTION
06-2020
001
Effluent
Chlorine, Total Residual
06/11/20
5 X week
ug/I
28
40
42.9
Daily Maximum
No Action, BPJ
Exceeded
06 -2020
001
Effluent
Chlorine, Total Residual
06/12/20
5 X week
ug/I
28
44
57.1
Daily Maximum
No Action, BPJ
Exceeded
06 -2020
001
Effluent
Chlorine, Total Residual
06/15/20
5 X week
ug/I
28
37
32.1
Daily Maximum
No Action, BPJ
Exceeded
06 -2020
001
Effluent
Chlorine, Total Residual
06/16/20
5 X week
ug/I
28
40
42.9
Daily Maximum
No Action, BPJ
Exceeded
06 -2020
001
Effluent
Chlorine, Total Residual
06/18/20
5 X week
ug/I
28
40
42.9
Daily Maximum
No Action, BPJ
Exceeded
06 -2020
001
Effluent
Chlorine, Total Residual
06/19/20
5 X week
ug/I
28
44
57.1
Daily Maximum
No Action, BPJ
Exceeded
06 -2020
001
Effluent
Chlorine, Total Residual
06/24/20
5 X week
ug/I
28
31
10.7
Daily Maximum
No Action, BPJ
Exceeded
06 -2020
001
Effluent
Chlorine, Total Residual
06/25/20
5 X week
ug/I
28
30
7.1
Daily Maximum
No Action, BPJ
Exceeded
06 -2020
001
Effluent
Chlorine, Total Residual
06/26/20
5 X week
ug/I
28
33
17.9
Daily Maximum
No Action, BPJ
Exceeded
06 -2020
001
Effluent
Chlorine, Total Residual
06/29/20
5 X week
ug/I
28
33
17.9
Daily Maximum
No Action, BPJ
Exceeded
10-2018
001
Effluent
Coliform, Fecal MF, MFC
10/06/18
5 X week
#/100ml
400
403.84
1.0
Weekly Geometric Mean
Proceed to NOD
Broth, 44.5 C
Exceeded
10-2018
001
Effluent
Coliform, Fecal MF, MFC
10/31/18
5 X week
#/100ml
200
215.13
7.6
Monthly Geometric Mean
Proceed to NOD
Broth, 44.5 C
Exceeded
12 -2018
001
Effluent
Flow, in conduit or thru
12/31/18
Continuous
mgd
4
5.13
28.3
Monthly Average
Proceed to
treatment plant
Exceeded
Enforcement Case
01 -2019
001
Effluent
Flow, in conduit or thru
01/31/19
Continuous
mgd
4
5.24
30.9
Monthly Average
Proceed to
treatment plant
Exceeded
Enforcement Case
03-2019
001
Effluent
Flow, in conduit or thru
03/31/19
Continuous
mgd
4
4.21
5.2
Monthly Average
Proceed to NOV
treatment plant
Exceeded
04 -2019
001
Effluent
Flow, in conduit or thru
04/30/19
Continuous
mgd
4
4.28
7.0
Monthly Average
Proceed to NOV
treatment plant
Exceeded

MONITORING REPORT(MR) VIOLATIONS for:
Permit: NCO020656 MRS Betweel 7 - 2016 and 7 - 2020 Region: %
Facility Name:% Param Name% County: %
Major Minor: %
Report Date: 08/20/2C Page 25 of 25
Violation Category:Limit Violation Program Category: %
Subbasin:% Violation Action: %
PERMIT: NCO020656 FACILITY: City of Laurinburg -Leith Creek WWTP COUNTY: Scotland REGION: Fayetteville
Limit Violation
MONITORING VIOLATION UNIT OF CALCULATED %
REPORT OUTFALL LOCATION PARAMETER DATE FREQUENCY MEASURE LIMIT VALUE Over VIOLATION TYPE VIOLATION ACTION
02-2020 001 Effluent Flow, in conduit or thru 02/29/20 Continuous
mgd
treatment plant
11 -2016 001 Effluent Mercury, Total (as Hg) - 11/30/16 Quarterly
ng/I
Concentration
05-2019 001 Effluent Nitrogen, Ammonia Total (as 05/31/19 5 X week
mg/I
N) - Concentration
4 4.62 15.6 Monthly Average Proceed to NOV
Exceeded
39 62 59.0 Annual Load Exceeded None
5 5.1 2.1 Monthly Average Proceed to NOD
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 15 I 3 I NC0020656 I11 121 19/06/26 I17 18 n 19 L G j 201
21111111111111111111111111111111111111111111 f6
Inspection
Work Days Facility Self -Monitoring Evaluation Rating B1 CA ---------------------- Reserved -------------------
67
70 �� LJ � 71 I tyI 72 L Ln, � 73LLI74 71
J 1 1 1 1 L L j80
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)
09:45AM 19/06/26
14/11/01
Leith Creek WWTP
Hall St Extension
Exit Time/Date
Permit Expiration Date
Laurinburg NC 28352
12:OOPM 19/06/26
19/08/31
Name(s) of Onsite Representative(s)/Titles(s)/Phone and Fax Number(s)
Other Facility Data
Dixon Lee Medlin/ORC/910-755-7921/
Name, Address of Responsible Official/Title/Phone and Fax Number
Contacted
Robert A. Ellis, PO Box 249 Laurinburg NC 283530249//910-276-9374/9102773633
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 Dispos Facility Site Review Effluent/Receiving Wate
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
Mark Brantley DWR/FRO WQ/910-433-3300 Ext.727/
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
31 NCO020656 I11 121 19/06/26 I17 18I„I
Section D: Summary of Finding/Comments (Attach additional sheets of narrative and checklists as necessary)
Comments
Facility was clean and neat in appearance at the time of the inspection.
DWR records do not have a back-up ORC listed for the Leith Creek WWTP. Please contact Maureen
Kinney with NC Operator Certification Program to designate a back-up ORC. She can be reached at
919-707-9038 or [e-mail].
Page#

Permit: NCO020656 Owner - Facility: Leith Creek WWTP
Inspection Date: 06/26/2019 Inspection Type: Compliance Evaluation
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:
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?
❑
❑
0
❑
Is access to the plant site restricted to the general public?
0
❑
❑
❑
Is the inspector granted access to all areas for inspection?
0
❑
❑
❑
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)?
0
❑
❑
❑
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 operatc
❑
❑
❑
on each shift?
Is the ORC visitation log available and current?
0❑
❑
❑
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?
❑
❑
❑
Page# 3

Permit: NCO020656 Owner - Facility: Leith Creek WWTP
Inspection Date: 06/26/2019 Inspection Type: Compliance Evaluation
Record Keeping Yes No NA NE
Facility has copy of previous year's Annual Report on file for review? ❑ ❑ ❑
Comment: DWR records do not have an ORC listed.
Effluent Pipe
Yes
No
NA
NE
Is right of way to the outfall properly maintained?
0
❑
❑
❑
Are the receiving water free of foam other than trace amounts and other debris?
0
❑
❑
❑
If effluent (diffuser pipes are required) are they operating properly?
❑
❑
0
❑
Comment:
Aerobic Digester
Yes
No
NA
NE
Is the capacity adequate?
0
❑
❑
❑
Is the mixing adequate?
0
❑
❑
❑
Is the site free of excessive foaming in the tank?
0
❑
❑
❑
# Is the odor acceptable?
0
❑
❑
❑
# Is tankage available for properly waste sludge?
0
❑
❑
❑
Comment:
Drying Beds
Yes
No
NA
NE
Is there adequate drying bed space?
0
❑
❑
❑
Is the sludge distribution on drying beds appropriate?
0
❑
❑
❑
Are the drying beds free of vegetation?
0
❑
❑
❑
# Is the site free of dry sludge remaining in beds?
0
❑
❑
❑
Is the site free of stockpiled sludge?
0
❑
❑
❑
Is the filtrate from sludge drying beds returned to the front of the plant?
0
❑
❑
❑
# Is the sludge disposed of through county landfill?
❑
❑
0
❑
# Is the sludge land applied?
0
❑
❑
❑
(Vacuum filters) Is polymer mixing adequate?
❑
❑
0
❑
Comment:
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
❑
❑
❑
Page# 4

Permit: NC0020656 Owner - Facility: Leith Creek WWTP
Inspection Date: 06/26/2019 Inspection Type: Compliance Evaluation
Flow Measurement - Effluent Yes No NA NE
(If units are separated) Does the chart recorder match the flow meter? ❑ ❑ 0 ❑
Comment:
Pump Station - Influent
Yes
No
NA
NE
Is the pump wet well free of bypass lines or structures?
0
❑
❑
❑
Is the wet well free of excessive grease?
0
❑
❑
❑
Are all pumps present?
0
❑
❑
❑
Are all pumps operable?
0
❑
❑
❑
Are float controls operable?
0
❑
❑
❑
Is SCADA telemetry available and operational?
0
❑
❑
❑
Is audible and visual alarm available and operational?
❑
❑
❑
Comment:
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:
Secondary Clarifier
Yes
No
NA
NE
Is the clarifier free of black and odorous wastewater?
0
❑
❑
❑
Is the site free of excessive buildup of solids in center well of circular clarifier?
0
❑
❑
❑
Are weirs level?
0
❑
❑
❑
Is the site free of weir blockage?
0
❑
❑
❑
Is the site free of evidence of short-circuiting?
0
❑
❑
❑
Is scum removal adequate?
0
❑
❑
❑
Is the site free of excessive floating sludge?
0
❑
❑
❑
Is the drive unit operational?
0
❑
❑
❑
Is the return rate acceptable (low turbulence)?
0
❑
❑
❑
Page# 5

Permit: NCO020656 Owner - Facility: Leith Creek WWTP
Inspection Date: 06/26/2019 Inspection Type: Compliance Evaluation
Secondary Clarifier Yes
No
NA
NE
Is the overflow clear of excessive solids/pin floc? 0
❑
❑
❑
Is the sludge blanket level acceptable? (Approximately'/4 of the sidewall depth) 0
❑
❑
❑
Comment:
Aeration Basins
Yes
No
NA
NE
Mode of operation
Ext. Air
Type of aeration system
Surface
Is the basin free of dead spots?
0
❑
❑
❑
Are surface aerators and mixers operational?
0
❑
❑
❑
Are the diffusers operational?
❑
❑
0
❑
Is the foam the proper color for the treatment process?
0
❑
❑
❑
Does the foam cover less than 25% of the basin's surface?
0
❑
❑
❑
Is the DO level acceptable?
0
❑
❑
❑
Is the DO level acceptable?(1.0 to 3.0 mg/1)
0
❑
❑
❑
Comment:
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?
0
❑
❑
❑
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/1)
0
❑
❑
❑
Are settelometer results acceptable?(400 to 800 ml/I in 30 minutes)
❑
❑
❑
Comment:
De -chlorination
Yes
No
NA
NE
Type of system ?
Gas
Is the feed ratio proportional to chlorine amount (1 to 1)?
0
❑
❑
❑
Is storage appropriate for cylinders?
0
❑
❑
❑
# Is de -chlorination substance stored away from chlorine containers?
0
❑
❑
❑
Comment:
Page# 6

Permit: NC0020656
Inspection Date: 06/26/2019
Owner - Facility: Leith Creek WWTP
Inspection Type: Compliance Evaluation
De -chlorination
Yes
No
NA
NE
Are the tablets the proper size and type?
❑
❑
0
❑
Are tablet de -chlorinators operational?
❑
❑
0
❑
Number of tubes in use?
Comment:
Standby Power
Yes
No
NA
NE
Is automatically activated standby power available?
0
❑
❑
❑
Is the generator tested by interrupting primary power source?
0
❑
❑
❑
Is the generator tested under load?
0
❑
❑
❑
Was generator tested & operational during the inspection?
❑
❑
❑
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 power?
❑
❑
❑
Is the generator fuel level monitored?
0
❑
❑
❑
Comment:
Equalization Basins
Yes
No
NA
NE
Is the basin aerated?
0
❑
❑
❑
Is the basin free of bypass lines or structures to the natural environment?
0
❑
❑
❑
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: Need to remove vexation from the bottom of the basin.
Disinfection -Liquid
Yes
No
NA
NE
Is there adequate reserve supply of disinfectant?
0
❑
❑
❑
(Sodium Hypochlorite) Is pump feed system operational?
0
❑
❑
❑
Is bulk storage tank containment area adequate? (free of leaks/open drains)
0
❑
❑
❑
Is the level of chlorine residual acceptable?
0
❑
❑
❑
Is the contact chamber free of growth, or sludge buildup?
0
❑
❑
❑
Is there chlorine residual prior to de -chlorination?
0
❑
❑
❑
Page# 7

Permit: NCO020656
Inspection Date: 06/26/2019
Disinfection -Liquid
Comment:
Influent Sampling
# Is composite sampling flow proportional?
Is sample collected above side streams?
Is proper volume collected?
Is the tubing clean?
Owner - Facility: Leith Creek WWTP
Inspection Type: Compliance Evaluation
# 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?
Comment:
Effluent Sampling
Is composite sampling flow proportional?
Is sample collected below all treatment units?
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 the facility sampling performed as required by the permit (frequency, sampling type
representative)?
Comment:
Upstream / Downstream Sampling
Is the facility sampling performed as required by the permit (frequency, sampling type, an(
sampling location)?
Comment:
Yes No NA NE
Yes
No
NA
NE
❑
❑
■
❑
■
❑
❑
❑
■
❑
❑
❑
■
❑
❑
❑
■
❑
❑
❑
■
❑
❑
❑
Yes
No
NA
NE
■
❑
❑
❑
■
❑
❑
❑
■
❑
❑
❑
■
❑
❑
❑
■
❑
❑
❑
■
❑
❑
❑
Yes No NA NE
■ ❑ ❑ ❑
Page# 8

Whole Effluent Toxicity Testing and Self Monitoring Summary
Laurel Road WTP NCO086975/001 County: Carteret
Mysd24PF Begin: 11/1/2017 Ac P/F Monit: 90% M NonComp:
J F M A M
2016 Pass - - Pass -
2017 Pass - - Pass -
2018 Pass - - Pass -
2019 Pass - - Pass -
2020 Pass - - Pass -
Region: WIRO Basin: WOK04 Jan Apr Jul Oct SOC JOC:
7Q10: PF: na IWC: Freq: Q
J J A 5 O N D
Pass - - Pass - -
Pass - - Pass - -
Pass - - Pass - -
Pass - - Pass - -
Pass
Laurinburg- Leith Creek WWTP
NCO020656/001
County: Scotland Region: FRO
Basin: LUM55 Feb May Aug Nov SOC JOC:
Ceri7dPF Begin:
11/1/2014 chr lim: 31%
NonComp: Single 7Q10: 13.8
PF: 4.0 IWC: 31 Freq: Q
J
F M
A M J J
A 5 O N D
2016 -
Pass -
- Pass - -
Pass - - Pass -
2017 -
Pass -
- Pass - -
Pass - - Pass >100(P) -
2018 -
Pass >100(P) -
- Pass >100(P) - -
Pass >100(P) - - Pass -
2019 -
Pass -
- Pass - -
Pass - - Pass -
2020 -
Pass -
- Pass - -
- - - - -
Laurinburg Maxton Airport -Laurel Hill NC0005479/001 County:
Scotland
Ceri7dPF Begin:
11/1/2009 chr lim: 1.5%
NonComp:
Single
J
F M
A
M
2016 -
- Pass
-
-
2017 Pass
- Pass
-
-
2018 -
- Pass
-
-
2019 -
- Pass
-
-
2020 -
- Pass
-
-
Laurinburg WTP, City of
NCO036773/001 County:
Scotland
Ceri7dPF Begin:
11/1/2014 Ceri7dPF Monit @ 90
NonComp:
J
F M
A
M
2016 -
Fail -
-
Fail
2017 -
Fail -
-
Fail
2018 -
Pass -
-
Fail
2019 -
Pass -
-
Pass
2020 -
Pass -
-
Pass
Laurinburg-Maxton Airport (LMAC) WW NCO044725/001 County:
Scotland
Ceri7dPF Begin:
11/1/2016 chr lim: 2.6%
NonComp:
Single
J
F M
A
M
2016 -
- Pass
-
-
2017 -
- Pass
-
-
2018 -
- Pass
-
-
2019 >10.4(P)
>10.4(P) >10.4(P) Pass
-
-
2020 -
- Pass
-
-
Region:
FRO
Basin:
LUM55
Mar Jun Sep Dec
SOC JOC:
7Q10: 31.0
PF: 0.3
IWC:
1.5 Freq: Q
J J
A
5
O
N
D
Pass -
-
Pass
-
-
Pass
Pass -
-
Pass
-
-
Pass
Pass -
-
Pass
-
-
Pass
Pass -
-
Pass
-
-
Pass
Pass -
-
-
-
-
-
Region:
FRO
Basin:
LUM55
Feb May Aug Nov
SOC JOC:
7Q10:
PF:
IWC:
Freq: Q
J J
A
5
O
N
D
- -
Fail
-
-
Pass
-
- -
Fail
-
-
Fail
-
- -
Pass
-
-
Pass
-
- -
Pass
-
-
Pass
-
Region:
FRO
Basin:
LUM51
Mar Jun Sep Dec
SOC JOC:
7Q10: 111.0
PF: 2.0
IWC:
1.3 Freq: Q
J J
A
5
O
N
D
Pass -
-
Pass
-
-
Pass
Pass -
-
Pass
-
-
Pass
Pass -
-
Pass
-
>10.4(P)
Pass
Pass -
-
Pass
-
-
Pass
Pass -
-
-
-
-
-
Legend: P= Fathead minnow (Pimphales promelas), H=No Flow (facility is active), s = Split test between Certified Labs Page 66 of 122