NC0024147_Fact Sheet_20220923

Fact Sheet
NPDES Permit No. NC0024147
Permit Writer/Email Contact Gary Perlmutter, [e-mail]:
Date: September 8, 2022
Division/Branch: NC Division of Water Resources / NPDES Municipal Permitting Unit
Fact Sheet Template: Version Jan 09, 2017
Permitting Action:
© Renewal
❑ Renewal with Expansion
❑ New Discharge
❑ Modification (Fact Sheet should be tailored to mod request)
1. Basic Facility Information:
Facility Information
Applicant/Facility Name:
City of Sanford / Big Buffalo Wastewater Treatment Plant (WWTP)
Applicant Address:
P.O. Box 3729, Sanford, NC 27331
Facility Address:
5327 Iron Furnace Road, Sanford, NC 27330
Permitted Flow:
12.0 MGD
Facility Type/Waste:
MAJOR Municipal; 89.62% domestic, 10.38% industrial 1
Facility Class:
Grade IV
Treatment Units:
Influent Distribution Box, Influent Screens, Influent Flow
Measurement, Grit Removal, Influent Pump Station, Equalization
Tank, BNR Basins, Secondary Clarifiers, Denitrification Filters, UV
Disinfection, Offsite Reclamation, Discharge Pipe and Outfall, Solids
Handling
Pretreatment Program (Y/N)
, Yes
County:
Lee
Region
Raleigh
Footnote.
1. Permitted industrial flow = 1.24 MGD
Briefly describe the proposed permitting action and facility background: The City of Sanford had applied
for an NPDES permit renewal for its Big Buffalo WWTP, received by DWR on March 22, 2022. Review
of the application found it complete with PPAs sampled in June 2018, March 2019, December 2020 and
September 2021; 2nd species WET tests were sampled in September 2017, June 2018, March 2019,
December 2020 and September 2021.
This facility serves the City of Sanford (pop. —26,945) and treats domestic and industrial wastewater with
an active pretreatment program involving 11 Significant Industrial Users (SIUs). The SIUs include nine
Categorical Industrial Users (CIUs): eight metal finishers (40 CFR 433) and one timber products processor
(40 CFR 429). Treated effluent management includes offsite water reclamation and onsite reuse as well as
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discharge to the Deep River via the NPDES program. Biosolids management include aerobic digestion,
dewatering and land application, the lattermost under permit WQ0000543).
2. Receiving Waterbody Information
Receiving Waterbody Information
Outfalls/Receiving Stream(s):
Outfall 001 at 35°33'03"N 79°13'29"W / Deep River
Stream Segment:
17-(38.7)
Stream Classification:
C
Drainage Area (mi2):
Ar 1148
Summer 7Q10 (cfs)
22.5
Winter 7Q10 (cfs):
33.6
30Q2 (cfs):
Average Flow (cfs):
126
IWC (% effluent):
45%
NC 2020 303(d) listed/parameter:
r None
Subject to TMDL/parameter:
State-wide Mercury TMDL
Basin/HUC:
I
Cape Fear / 0303000306
USGS Topo Quad:
E22SW / Colon, NC
The current critical streamflows were provided by USGS via the Permittee's request for a permit
modification for expansion in 2010. The current IWC is based on the above USGS-provided streamflows,
increased from a former value of 39%.
3. Effluent Data Summary
Effluent data for Outfall 001 are summarized in Table 1 for the period from April 2018-March 2022.
Table 1. Effluent Data Summary Outfall 001.
Parameter
Units
Average
Max
Min
Permit Limit 1
Flow 2
_ MGD
5.413
29.923
1.782
MA = 12.0
CBOD5 (Apr -Oct)
mg/L
2.5
7.7
< 2.0
MA = 5.0
WA = 7.5
CBOD5(Nov-Mar)
mg/L
2.8
25.0
< 2.0
MA = 9.2
WA = 14.2
CBOD removal
%
98.5
99.6
81.7
> 85
TSS
mg/L
3.4
128
< 2.5
MA = 30.0
WA = 45.0
TSS removal
%
98.1
22.1
99.6
> 85
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Parameter
Units
Average
Max
Min
Permit Limit 1
NH3-N (Apr -Oct)
mg/L
0.74
6.70
< 0.04
MA = 1.0
WA = 3.0
NH3-N (Nov -Mar)
mg/L
0.69
4.16
< 0.04
MA = 1.1
WA = 3.4
Fecal Coliform
(geometric mean)
#/100 mL
12.1
> 2420
1
MA = 200
WA = 400
Dissolved Oxygen
mg/L
8.5
11.1
5.6
DMin > 5.0
pH
S.U.
6.6
7.2
5.4
6.0-9.0
Temperature
°C
20.4
28.0
12.0
Conductivity
µmhos/cm
553
881
121
Total Phosphorus (TP)
mg/L
2.29
14.88
< 0.10
TP Load (Apr -Oct)
lb/mo
1,993
5,252
153
TP Load (Apr -Oct)
lb/season
Summer 2018 = 15,867
Summer 2019 = 19,623
Summer 2020 = 15,821
Summer 2021 = 4,147
SM = 20,138
Total Nitrogen (TN)
mg/L
4.52
19.10
0.83
TN Load (Apr -Oct)
lb/mo
4,640
15,223
1,960
TN Load (Apr -Oct)
lb/yr
Summer 2018 = 41,903
Summer 2019 = 36,295
Summer 2020 = 33,061
Summer 2021 = 17,345
SM = 64,628
Total Kjeldahl Nitrogen
(TKN)
mg/L
1.57
16.30
0.20
Nitrate -Nitrite
(NO3+NO2)
mg/L
3.06
14.96
0.48
Total Copper
µg/L
4
58
< 2
Hardness
mg/L
65
100
Footnotes.
1. MA = Monthly Average, WA = Weekly Average, DMin = Daily Minimum; SM = Summer Maximum; CY
= calendar year.
2. Average for CY2021 = 4.113 MGD, 34% of design flow.
Flows were elevated, peaking with the maximum of 23.32 MGD in September 2018 are attributed to the
effects of flooding associated with Hurricane Florence.
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
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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 (Y/N): Yes.
Name of Monitoring Coalition: Upper Cape Fear River Basin Association (UCFRBA).
If applicable, summarize any instream data and what instream monitoring will be proposed for this permit
action: The current permit has instream monitoring requirements for Dissolved Oxygen, Temperature, and
Conductivity at frequencies of weekly from October through May and 3/week from June through
September. In addition is quarterly upstream monitoring for Hardness to calculate instream water quality
standards for hardness -dependent metals (see Reasonable Potential Analysis section below). The upstream
sampling location is Deep River at Cumnock Rd Bridge and the downstream location is at US Hwy 15-501.
Instream data from April 2018—December 2021 were obtained from DWR's monitoring coalition database
for UCFRBA stations B5685000 (upstream at Deep River Park bridge near Cumnock Rd) and B5820000
(downstream at US Hwy 15-501) for review. These data were checked for statistically significant
differences by Student's t-test and compared against concurrent effluent data as well as applicable state
water quality standards (WQS). Statistical significance level (p-value) was set at 0.05. Instream data review
findings for each parameter are summarized in Table 2 below.
Table 2. Instream and concurrent effluent monitoring summary statistics.
Parameter
Upstream
Downstream
Effluent
Standard
Dissolved Oxygen
(DO), mg/L
Average = 7.25
Range: 4.51-11.70
Average = 7.17
Range: 4.40-11.40
Average = 8.17
Range: 6.40-11.1
DA = 5.0
Instant = 4.0
Temperature, °C
Average = 20.8
Range: 6.6-31.2
Average = 20.9
Range: 6.8-30.9
Average = 21.8
Range: 13.0-28.0
DM — 32.0
Conductivity
(umhos/cm)
Average = 112
Range: 64-190
Average = 121
Range: 66-212
Average = 572
Range: 329-810
Fecal Coliform,
cfu/100 mL
Geomean = 189
Range: 21-8,800
Geomean = 169
Range: 19-14,000
Geomean = 13
Range: 1-2,420
MA = 200
WA = 400
Dissolved Oxygen (DO) — DO remains in the permit as a parameter of concern for aquatic life. The receiving
stream segment is meeting criteria for DO in the 2020 Integrated Report. Instream average DO did not test
significantly different between sites, but the concurrent average effluent DO tested higher than both
instream DO averages.
Temperature — Temperature remains in the permit as a parameter of concern for aquatic life. The receiving
stream is meeting criteria for temperature in the 2020 Integrated Report. Reviewed instream temperature
data showed seasonal patterns of summer highs and winter lows at both locations. Summer temperature
maxima at both stations were below the WQS of 32°C for lower piedmont and coastal plain waters (15A
NCAC 02B .0211). No statistical differences were found between upstream and downstream average
temperatures. Review of paired up- to downstream temperatures found no exceedances of the 2.8°C
increase standard (15A NCAC 02B .0211). Concurrent effluent temperatures were consistently higher in
winter months.
Conductivity — Conductivity remains in the permit as a parameter of concern due to industrial discharges.
Big Buffalo WWTP treats industrial waste via a pretreatment program. Review of instream data yielded no
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statistically significant difference between the up- and downstream average conductivity. However, effluent
conductivity was substantially higher.
Fecal Coliform — Fecal Coliform is a parameter of concern for aquatic life and human health, but was
removed from the permit in 2017 since it was found that the receiving water is neither a Class B nor
impaired for fecal coliform. Instream data collected by UCFRBA are available for review. Downstream
geomean was lower than the upstream, and the effluent geomean was substantially lower than either
instream geomean. Fecal Coliform monitoring is not required and will not be added to the permit.
Additional Instream Parameters — The UCFRBA also monitored the instream stations for Ammonia -
Nitrogen (NH3-N), Inorganic Nitrogen (NO2+NO3), Total Kjeldahl Nitrogen (TKN), pH, Phosphorus, and
Turbidity. Since the permit has effluent requirements for these parameters except Turbidity, and they were
reviewed in the previous fact sheet, instream data were reviewed for potential impact. Among these
instream parameters only TKN showed a statistical difference between stations with concentrations higher
downstream (Table 3).
Table 3. Instream and concurrent effluent monitoring summary statistics — additional parameters.
Parameter
Upstream
IT Downstream
Effluent
Standard
NH3-N (mg/L)
Average = 0.03
Range: 0.02-0.25
Average = 0.05
Range: 0.02-0.38
Average = 0.74
Range: 0.04-1.00
NO2+NO3 (mg/L)
Average = 0.4;
Range: 0.02-0.93
Average = 0.62*
Range: 0.03-1.40
Average = 3.36
Range: 0.48-14.84
TKN (mg/L)
Average = 0.79
Range: 0.38-1.36
Average = 0.86
Range: 0.43-2.31
Average = 1.39
Range: 0.59-2.31
pH (SU)
Average = 6.85
Range: 6.20-7.22
Average = 6.87
Range: 6.31-7.27
Average = 6.6
Range: 6.30-7.10
6.0 — 9.0
Phosphorus
(mg/L)
Average = 0.108
Range: 0.020-0.317
Average = 0.155
Range: 0.034-0.558
Average = 1.45
Range: 0.10-3.60
Turbidity (NTU)
Average = 22.2
Range: 2.9-98.4
Average = 23.0
Range: 2.8-104
NA
50
* = statistical) different between instream stations.
NIL
No changes to the permit for instream monitoring.
5. Compliance Summary
Summarize the compliance record with permit effluent limits (past 5 years): From April 2017 through
March 2022, five pH values were reported below the minimum of 6.0 SU in September 2018 and March
2019, each resulting in a Notice of Violation.
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 from March 2018 through March
2022 as well as all four 2nd species WET tests, sampled in June 2018, March 2019, December 2020, and
September 2021.
Summarize the results from the most recent compliance inspection: The most recent facility compliance
inspection, conducted on 6/1/2021, reported that the influent pump station and surrounding berm were
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under construction after flooding from Hurricane Florence in 2018; otherwise, no compliance issues. The
report recommended that the Permittee include the influent pump station in the permit renewal; it is included
in the process narrative tab of the renewal package. The most recent pretreatment compliance inspection
was conducted on 9/17/2021; no comments were provided in the report. A toxicity inspection was
conducted on 3/15/2022, with the sample results passing.
6. Water Quality -Based Effluent Limitations (WQBELs)
Dilution and Mixing Zones
In accordance with 15A NCAC 2B.0206, the following streamflows are used for dilution considerations
for development of WQBELs: 1 Q 10 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: The CBOD annual
loading was maintained upon expansion to the current permitted flow of 12.0 MGD in the 2010 permit
modification, resulting in the current limits.
Ammonia and Total Residual Chlorine Limitations
Limitations for ammonia are based on protection of aquatic life utilizing an ammonia chronic criterion of
1.0 mg/L (summer) and 1.8 mg/L (winter). Acute ammonia limits are derived from chronic criteria, utilizing
a multiplication factor of 3 for Municipals and a multiplication factor of 5 for Non -Municipals.
Limitations for Total Residual Chlorine (TRC) are based on the NC water quality standard for protection
of aquatic life (17 µg/L) and capped at 28 µg/L (acute impacts). Due to analytical issues, all TRC values
reported below 50 µg/L are considered compliant with their permit limit.
Describe any proposed changes to ammonia and/or TRC limits for this permit renewal: The current
Ammonia limits were originally set to protect the dissolved oxygen standard, based on maintaining the
annual load upon expansion to the current flow in the 2010 permit modification. Ammonia was reviewed
in the attached Wasteload Allocation (WLA) sheet using the design flow of 12.0 MGD and receiving stream
low flow of 7Q10 = 22.5 cfs (summer) and 33.6 cfs (winter). The resulting allowable concentrations are
less stringent than the current limits. No changes are proposed for Ammonia.
The current permit lacks TRC limits, having been removed in the 2017 permit since the facility disinfects
using UV. In the event that the facility uses chlorination, TRC was reviewed via the WLA sheet as for
Ammonia above. The resulting allowable concentration was 38 µg/L; a limit capped at 28 µg/L has been
added to the permit.
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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 Y2 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 are available among submitted DMR data. Monthly upstream data, sampled from
June 2020 through December 2021, were not submitted via DMR but separately with the application.
A reasonable potential analysis was conducted on effluent toxicant data collected between April 2018 and
March 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 Monitoring. The following parameters will receive a water quality -based
effluent limit (WQBEL) since they demonstrated a reasonable potential to exceed applicable water
quality standards/criteria: None.
• Monitoring Only. The following parameters will receive a monitor -only requirement since they
did not demonstrate reasonable potential to exceed applicable water quality standards/criteria, but
the maximum predicted concentration was > 50% of the allowable concentration: 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 Beryllium, Total Cadmium, Chloride, Total Phenolic Compounds, Total
Chromium, Total Copper, Total Cyanide, Total Fluoride, Total Lead, Total Molybdenum, Total
Nickel, Total Selenium, Total Silver, Total Zinc.
• POTW Effluent Pollutant Scan Review: Three effluent pollutant scans were evaluated for
additional pollutants of concern. Four PPAs, sampled in June 2018, March 2019, December 2020,
and September 2021, were reviewed.
• 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.
• 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, or the maximum predicted
concentration was > 50% of the allowable 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: All
parameters were non -detects.
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
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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 facility is a Major POTW with a chronic WET limit at
45% effluent, sampled quarterly. The WET limit is based on the Instream Waste Concentration (IWC) as
calculated from the design flow tier of 12.0 MGD and the summer receiving stream 7Q10 of 22.5 cfs (WET
Permitting Limits and Monitoring Requirements guidance memo, 8/2/1999).
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/L) 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/L) and/or if any individual value exceeds a TBEL value of 47 ng/L.
Describe proposed permit actions based on mercury evaluation: No mercury requirements are in the
current permit, based on the previous permit cycle data being all below detection. Submitted low level
mercury data from June 2018 through March 2022 were reviewed for TMDL evaluation. No individual
results exceeded the TBEL of 47 ng/L and no annual average exceeded the WQBEL of 26.52 ng/L (Table
4). Because mercury was detected in the effluent (> 1 ng/L) and the design flow is > 2 MGD, a MMP is
required and will be added to the permit.
Table 4. Mercury Effluent Data Summary.
Parameter
2018
2019
2020
2021
2022
No. of Samples
4
4
4
4
4
Annual Average Conc. ng/L
1.0
1.6
0.5
0.5
0.5
Maximum Conc., ng/L
2.62
4.70
0.50
0.50
0.50
TBEL, ng/L
47
WQBEL, ng/L
26.52
Other TMDL/Nutrient Management Strategy Considerations
If applicable, describe any other TMDLs/Nutrient Management Strategies and their implementation within
this permit: Individual TN (64,628 lbs/summer season) and TP (20,138 lbs/summer season) effluent limits
were maintained in the permit renewal to comply with the 2011 final draft nutrient permitting strategy for
the Upper Cape Fear River Basin, which includes the Deep River watershed. This strategy was drafted for
the Cape Fear River Basin Plan to address Chlorophyll -a impairment of the Cape Fear River near Buckhorn
Dam, approximately 17.5 river miles downstream of the discharge. These summer mass load limits have
been in effect since the facility's expansion to 12.0 MGD on September 20, 2014, to hold the load per the
strategy. Also in the permit in accordance with the strategy are special conditions for nutrient load
calculations [A. (5)] and reopening the permit for supplemental monitoring [A. (4.)]. A TMDL is in
progress. To aid load calculations, total monthly flow has been added to the permit.
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Other WQBEL Considerations
If applicable, describe any other parameters of concern evaluated for WQBELs: The City submitted
sampling results of influent and effluent 1,4-Dioxane and PFAS compounds from multiple samplings in
2019 and 2020 with the application.
Table 4. Effluent Monitoring Results of Emerging Contaminants for the limited period of
January -June 2020.
Parameter
Average (Range)
Drinking Water
Health Advisory
1,4-Dioxane, µg/L
1.56 (< 1.00-2.43)
35 µg/L
Perfluorooctanoic Acid (PFOA), ng/L
12.39 (9.23-15.20)
*
Perfluorooctanosulfonic Acid (PFOS), ng/L
11.72 (7.40-14.3)
Perfluoroheptanoic Acid (PFHpA), ng/L
_ 36.56 (14.30-75.70)
NA
Perfluorohexanoic Acid (PFHxA), ng/L )
49.47 (ND-70.80)
NA
6:2 Fluorotelomer Sulfonate (6:2 FTS), ng/L
71.90 (23.00-124.00)
NA
*Note that EPA's recent health advisory for PFAS is non -enforceable and non -regulatory and provide technical
information to states agencies and other public health officials on health effects, analytical methods, and treatment
technologies associated with drinking water contamination.
Big Buffalo WWTP discharges into a Class C waterbody with a water supply watershed located —7.5 miles
downstream. Because 1,4-Dioxane was detected at concentrations high enough for further evaluation,
monthly monitoring for this parameter will be added to the permit. In addition, a permit reopener special
condition regarding 1,4-Dioxane based on changes toward limits, monitoring or treatment will be added to
the permit.
Based on detection of PFAS chemicals (including PFOA and PFOS and the relatively high values for
PFHpA, PFHxA and 6:2 FTS) reported in the Chemical Addendum, monitoring of PFAS chemicals will be
added to the permit at a quarterly frequency. Since an EPA method for sampling and analyzing PFAS in
wastewater is not currently available, 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 CFR 136 published in the Federal Register. This
date may be extended upon request and if there are no NC -certified labs.
If applicable, describe any special actions (HQW or ORW) this receiving stream and classification shall
comply with in order to protect the designated waterbody: NA.
If applicable, describe any compliance schedules proposed for this permit renewal in accordance with 15A
NCAC 2H.0107(c)(2)(B), 40CFR 122.47, and EPA May 2007 Memo: NA.
If applicable, describe any water quality standards variances proposed in accordance with NCGS 143-
215.3(e) and 15A NCAC 2B. 0226 for this permit renewal: NA.
7. Technology -Based Effluent Limitations (TBELs)
Municipals (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
BOD5/TSSfor Monthly Average, and 45 mg/L for BOD5/TSSfor Weekly Average). YES.
Page 9 of 14

If NO, provide a justification for alternative limitations (e.g., waste stabilization pond). NA.
Are 85% removal requirements for BOD5/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.
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 2B.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.
The current permit has reduced monitoring frequencies for BOD, TSS, and Fecal Coliform. The City
requested continuation of reduced monitoring for these parameters plus Ammonia in the permit renewal
application. Review of submitted data found all target parameters to meet numeric criteria. Reduced
monitoring frequencies of the above parameters has been maintained in the permit; monitoring for
Ammonia has been reduced to 2/week.
For instream monitoring, refer to Section 4.
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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 Federal Register in November 2, 2020 This permit contains the
requirements for electronic reporting, consistent with Federal requirements.
12. Summary of Proposed Permitting Actions
Table 5. Current Permit Conditions and Proposed Changes.
Parameter
Current Permit 1
Proposed Change
Basis for Condition/Change
Flow
MA = 12.0 MGD
No change
15A NCAC 02B .0400 at seq., 02B
0500 et seq.
Total Monthly Flow
No requirement
Add monthly
monitoring
To aid in calculating nutrient loads
CBOD5 '
Summer
MA = 5.0 mg/L
WA = 7.5 mg/L
Winter
MA = 9.2 mg/L
WA = 14.2 mg/L
Monitor 2/week
No change
WQBEL. Based on maintaining load
upon expansion to current permitted
flow in 2010. 15A NCAC 2B.0200.
Monitoring frequency reduction
(MFR) criteria met.
TSS
MA = 30.0 mg/L
WA = 45.0 mg/L
Monitor 2/week
No change
TBEL. Secondary treatment
standards / 40 CFR 133 / 15A NCAC
2B .0406. MFR criteria met.
1
1
NH3-N
Summer
MA = 1.0 mg/L
WA = 3.0 mg/L
Winter
MA = 1.1 mg/L
WA = 3.4 mg/L
Monitor Daily
No change in limits
Reduce monitoring to
2/week
WQBEL. Based on EPA criteria,
state guidance for toxicity protection.
MFR criteria met.
Fecal Coliform
MA = 200 /100 mL
WA = 400 /100 mL
Monitor 2/week
No change
WQBEL. State WQ standard, 15A
NCAC 2B .0200. MFR criteria met.
Total Residual Chlorine
(TRC)
No requirement
Add daily max. limit
of 28 µg/L to be
applied when
chlorine is used.
WQBEL. State WQ standard, 15A
NCAC 2B .0200.
Dissolved Oxygen (DO)
DM > 5.0 mg/L
Monitor daily
No change
WQBEL. State WQ standard, 15A
NCAC 2B .0200., .0500.
Page 11 of 14

Parameter
Current Permit 1
Proposed Change
Basis for Condition/Change
pH
6 — 9 SU
Monitor daily
No change
WQBEL. State WQ standard, 15A
NCAC 2B .0200, .0500.
Temperature
Monitor daily
No change
State WQ reporting requirements
15A NCAC 2B .0500.
Conductivity
Monitor daily
No change
State WQ reporting requirements
15A NCAC 2B .0500; facility treats
industrial waste.
Total Phosphorus (TP)
Monitor weekly
No change
State WQ reporting requirements
15A NCAC 2B .0500. Cape Fear
River Basin Permitting Strategy.
TP Load
20,138 lb/summer
(Apr -Oct)
Monitor monthly,
seasonally
No change
WQBEL. Cape Fear River Basin
Permitting Strategy.
Total Nitrogen (TN)
Monitor weekly
No change
State WQ reporting requirements
15A NCAC 2B .0500. Cape Fear
River Basin Permitting Strategy.
TN Load
64,628 lb/summer
(Apr -Oct)
Monitor monthly,
seasonally
No change
WQBEL. Cape Fear River Basin
Permitting Strategy.
TKN
Monitor weekly
No change
State WQ reporting requirements
15A NCAC 2B .0500. Cape Fear
River Basin Permitting Strategy.
NO2+NO3
Monitor weekly
No change
State WQ reporting requirements
15A NCAC 2B .0500. Cape Fear
River Basin Permitting Strategy.
Total Copper
Monitor quarterly
Remove from permit
No Reasonable Potential (RP) to
exceed WQS found.
Total Hardness
Monitor quarterly
No change
Hardness -dependent dissolved metals
water quality standards, approved in
2016, need effluent hardness data for
calculations of permit limitations.
Mercury
No requirement
Add Mercury
Minimization Plan
2012 Statewide Mercury TMDL
Implementation
1,4-Dioxane
No requirement
Add monthly
monitoring; add
reopener special
condition
Based on limited effluent data
showing detection, more results are
needed to evaluate.
PFAS
No requirement
Add quarterly
monitoring with
delayed
implementation
Based on limited effluent data
showing detection, more results are
needed to evaluate. Implementation
delayed until after EPA certified
method becomes available.
Page 12 of 14

Parameter
Current Permit 1
Proposed Change
Basis for Condition/Change
Toxicity Test
Chronic
Ceriodaphnia
dubia Pass/Fail at
45% effluent
No change
WQBEL. No toxics in toxic
amounts. 15A NCAC 2B.0200 and
15A NCAC 2B.0500.
Effluent Pollutant Scan
Monitor 3 years per
permit cycle
Update sample years:
2024, 2025, 2026.
40 CFR 122
Electronic Reporting
Special Condition
Update special
condition
In accordance with EPA Electronic
Reporting Rule 2015.
Footnote
1. MGD = Million gallons per day; MA = Monthly Average; WA = Weekly Average; DM = Daily Maximum;
QA = Quarterly Average.
13. Public Notice Schedule:
Permit to Public Notice: 09/22/2022.
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 questions regarding any of the above information or on the attached permit, please contact Gary
Perlmutter at [phone] or via email at [e-mail].
15. Fact Sheet Addendum (if applicable):
Were there any changes made since the Draft Permit was public noticed (Yes/No): No.
If Yes, list changes and their basis below:
16. Fact Sheet Attachments:
• NPDES PT POCs review form
• Effluent summary charts and tables
• Instream summary charts and tables
• NC 2020 Integrated Report, p. 110
• Monitoring Report (MR) Violations page
• WET testing and Self -Monitoring Summary, page 94
• Compliance Inspection Report, 6/1/2021
• Pretreatment Inspection Report, 9/17/2021
• Toxicity Inspection Report, 3/15/2022
• NH3/TRC WLA Calculations sheet
Page 13 of 14

• Freshwater RPA spreadsheet
• Mercury WQBEL/TBEL Evaluation data and summary table
• 2011 Cape Fear River Basin Plan & NPDES Permitting Strategy
• Monitoring Frequency Reduction Evaluation
1
1
1
1
Page 14 of 14

A B) C IDIEIPI GI HIIIJI K ) L ) M
N ) 0 ) P
1
2
8
4
5
6
7
8
g
10
11
12
13
NPDES/PT
POC Review Form
Ility's General Information
Version: 2022.03.04
Date of (draft) Review
4/21/2022 - 7/15/2022
C. POC review due to:
e. Contact Information
Date of (foal) Review
ii a
Municipal NPDES renewal
❑
Regional Office (RO)
Raleigh
NPDES Permit Writer
Gary Perlmutter
New Industries
❑
RO PT Staff
Cheng
Zhang
RO NPDES Staff
Scott Vinson
Permttee-Facility Name
City of Sanford - Big Buffalo WWTP
WWTP expansion
0
Facility PT Staff, email
Sarah Jordan, sarah.lordanTr45anfordno.net
NPDES Permit Number
NC0024147
Stream reclass./adjustment
0
f. Receiving Stream
NPDES Permit Effective Date
Curial! relocation/adjustment
0
Outfall I
NPDES Permit Renewal
Application Dale
3/22/2022
7010 update
Receiving Stream:
Deep River
OA, cfs:
1260
NPDES Permit Public Notice
Date
Other, explain below
Stream Class
C
7010 (S), cfs:
22.5
eDMR data evaluated from:
to i
Comments on POC review trigger:
Oufall Let.
35°33'03" N
Ouffall Lang.
79°13'29" W
a. WWTP Capacity Summary
The City of Sanford submitted an
Outfa1111
Current Permitted Flow, mgd
12.0
Designed Flow,
mgd
12.0
application for the renewal of its Big Buffalo
WWTP in March 2022.
Receiving Stream:
IM
QA, cfs:
14
15
117Permitted
i6
SIU Flow, mgd
1.25
d. IU Summary
Stream Class
7010, cfs:
b. PT Docs. Summary
# IUs
12
Duran Lat.
Dudall Long.
IW S approval date
8/10/2018
# SIUs
12
Comments:
USTMP approval date:
3/12/2015
# CIUs
9
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
# NSCIUs
0
HWA approval date
2/22/2018
# !Us w/Local
Permits w Other
Types
2.
Industrial Users' Information.
#
Industrial User (IU) Name
IU Activity
IU Conventional
Pollutants
IU Non Conventional Pollutans & Toxic Pollutant
IUP Effective Date
1
Arauco Panels USA, LLC
Timber
Products
See
POC Table
See POC Table
8/1/2021
2
ASCfTrion
Metal
Finisher
See
POC Table
See POC Table
9/30/2019
a
i
Caterpillar - Boone Trail
Metal
Finisher
See
POC Table
See POC Table
9/30/2019
.E 4
`m
Caterpillar - Womack
Metal
Finisher
See
POC Table
See POC Table
9/30/2019
a
w
Charah, LLC
Coal Ash
Mgmt
See
POC Table
See POC Table
8/1/2021
a 6
Coty US, LLC
Cosmetics
See
POC Table
See POC Table
9/30/2019
Z
7
Hydrotybe Enterprises, Inc
Metal
Finisher
See
POC Table
See POC Table
9/30/2019
e
MagnetMarelli Powertrain USA, LLC
Metal
Finisher
See
POC Table
See POC Table
9/30/2019
6
Moen Inc
Metal
Finisher
See
POC Table
See POC Table
9/30/2019
10
STI Polymer
Orgaarnnic
See
POC Table
See POC Table
9/30/2019
11
Tyson Foods Inc. Mexican Original
Food
See
POC Table
See POC Table
3/21/2022
12
Wyeth (Pfizer)
Pharma.
See
POC Table
See POC Table
9/30/2019
Comment: I Magfneti Marelli IUP was rescinded in December
2021.
Static Controls IUP was dropped in 2019.
3. Comments from NPDES pw
Facility Summary and NPDES regulatory action:
Comments from NPDES pw to PT staff (Central, RO, Facility):
The City of Sanford had applied for an NPDES permit renewal for its
22e,
by4D5)WaRnnd otnr
Big Buffalo
please maintain the following POC-NPDES
required pollutants:37SWaWnfTrPd,
s2ti0c2a2n. dTihnids ufsaciilaitl
(rpeocpeive2d6eMatasrcdhomwastewater
active pretreatment program involving 11 Significant Industrial Users
SIUs include Categorical Industrial Users finishers
wCiith aon
(SIUs). The
POC that need to be added/modified in
USTMP sampling plan:
1,4-Dioxane, PFAS
nine (ClUs): eight metal
CFR 433) and one timber products processor (40 CFR 429). Treated
(40
effluent
pOC that may be removed from USTMP
sampling plan:
management includes offsite water reclamation and onsite reuse as
discharge to the Deep River via the NPDES program. Biosolids management
Include aerobic digestion, dewatering and land application, the lattermost
well as
under
ORC's comments on IU(POC:
permit W00000543).
Additional pollutants added to USTMP due
to POTWs concerns:
NPDES pw's comments on Ills
4. Status of Pretreatment Program (check all that apply)
Status of Pretreatment Program (check all that apply)
❑
1) facility has no SIU's, does have Division approved Pretreatment
Program that
is INACTIVE
0
2) facility has no SIU's, does not have Division approved Pretreatment
Program
0
3) facility has SIUs and DWQ approved Pretreatment Program
2
3a) Full Program with LTMP
❑
3b) Modified Program with STMP
0
4) additional conditions regarding Pretreatment attached or listed below
2
5) facility's sludge is being land applied or composted
0
6) facility's sludge is incinerated (add Beryllium and Mercury sampling according to § 503.43)
0
7) facility's sludge is taken to a landfill, if yes which landfill:
0
8) other 1
I
I
Sludge Disposal Plan:
Land application.
58
Sludge Permit No:
W00000543
Page 1
24147 POC Review Form 2022

A B) C ) D ) E ) F ) G ) H ) I ) J ) K ) L ) M ) N ) 0 ) P
59
60
61
62
5. LTMP/STMP and HWA Review
PW: Find S/LTMP document, HWA spreadsheet, DMR, previous and new NPDES permit for next section.
a
2
y
L-
p
o.
Parameter of
Concern (POC)
Check List
New
NPDES
POC
Previous
NPDES
POC
Required by
EPA PT(1)
POC due to
Sludge
POC due to
SIU (3)
POTW
POC (4)
%
Removal
Rate
L/STMP
Effluent Freq
NPDES
Effluent Freq
PQLs review
Comment
PQL from
S/LTMP, ug/I
Required PQL
per NPDES
permit
Recomm.
PQL, ug/I
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
93
94
95
96
97
98
99
100
101
102
103
104
MUM
0
Flow
0
0
❑
,
O
CBOD
0
0
0
0
2.0 mg/L
0
TSS
0
0
0
❑
2.5 mg/L
0
NH3
0
0
0
0
0.1 mg/L
0
Arsenic
0
0
0
0
0
5.0
2.0
Lower PQL to recommended
❑
Barium
❑
0
0
❑
0
❑
Beryllium(5)
0
0
❑
0
0
Cadmlum(1)
❑
0
0
0
0
0
2.0
0.5
Lower PQL to recommended
0
Chromium(1)
0
0
0
0
0
0
5.0
10.0
0
Copper(1)
0
0
0
X
0
❑
5.0
2.0
Lower PQL to recommended
0
Cyanide
0
❑
0
0
10.0
0
Lead(1)
❑
0
0
17
0
❑
5.0
2.0
Lower PQL to recommended
0
Mercury(5)
❑
0
El
0
0
0.001
0.001
0
Molybdenum
❑
0
X
0
❑
100.0
10.0
Lower PQL to recommended
0
Nickel(1)
0
❑
0
X
0
0
10.0
5.0
Lower PQL to recommended
❑
Selenium
❑
0
0
0
0
10.0
❑
Silver
0
❑
❑
0
0
5.0
1.0
Lower PQL to recommended
0
Zinc(1)
❑
0
0
X
0
0
10.0
10.0
❑
Sludge Flow to Disposal
0
❑
❑
0
% Solids to Disposal
0
❑
❑
0
Oil & Grease
❑
❑
❑
TN
0
0
x
❑
0
❑
TP
❑
0
x
0
0
0
PFAS 1633
❑
U
❑
❑
Recommend odd to LTMP
0
1,4 Dioxane
0
0
❑
❑
Recommend odd to LTMP
❑
❑
0
0
❑
❑
0
❑
0
❑
0
El0
0
0
0
■
❑
0
0
0
I
I
Footnotes:
(1) Always in the LTMP/STMP due to EPA -PT requirement
(2) Only in LTMP/STMP if sludge land app or compost (dif POC for incine ators)
(3) Only in LTMP/STMP while SIU still discharges to POTW
(4) Only in LTMP/STMP when pollutant is still of concern to POTW
(5) In LTMP/STMP, if sewage sludge is incinerated (Follow instruc0ons for Be and Hg according to § 503.43)
Please use blue font for the info updated by pw
Please use red font for POC that need to be addedlmodlfled In LJSTMP sampling plan
Pie
Blue shaded cell:
Parameters usually included under that POC list
I I I
6. Pretreatment
updates in response to NPDES permit renewal
i Permit writer, please add list of required/recommended PT updates in NPDES permit cover letter.
[VDU Permit Effective Date I180 days after effective (date): I
Page 2 24147 POC Review Form 2022

Big Buffalo WWTP
Effluent Monitoring NC0024147
14
12
10
0 8
2 6
4
2
0
Flow
• Mo Avg Limit
•
• •
•
•
• • • ~•• ••••• •• • •••
�•
••• ••• •• •
•••••
oti oti oti▪ ' oti° oti° oti° otiti Ol> o�� o��
o\���ti �\yo�ti °\���ti h\���ti ��\N, o\y��ti �\1�ti �\���ti �\�\ti �\�\\ti
16
14
12
J 10
E 8
6
4
2
0
Carbonaceous BOD (CBOD)
• Wk Avg ♦ Mo Avg WA Limit — — MA Limit
4-0;;;atAkielti
♦I
•
- d
•
~ •
•
oti oti oti oti° oti° oti° oti otiti oti oti
°\�v�ti ��ti°\� �o\�cb �\ti h\yh�ti �.ti�ti o\��ti \)\
Removal rate
120%
100%
80%
60%
40%
20%
0%
CBOD Removal
• Effluent —Limit
•
• •
oti oti oti' oti° otio oti Ol> otiti o'Cv oti
h\ D\ti o\y��ti \��ti A\\��ti cb\���ti
Summary Statistics
N 1461
Avg 5.413
SD 2.442
Min 1.782
Max 29.923
Summary Statistics
Summer
N 264
Avg 2.5
SD 0.9
Min 2.0
Max 7.7
Winter
N 152
Avg 2.8
SD 2.8
Min 2.0
Max 25.0
Summary Statistics
N 431
Avg 98.5%
SD 0.016
Min 81.7%
Max 99.6%
Page 1 of 6 GB Perlmutter 9/23/2022

Big Buffalo WWTP Effluent Monitoring NC0024147
50
45
40
35
30
Total Suspended Solids (TSS)
• Wk Avg • Mo Avg
WA Limit • MA Limit
—ao 25
20
15
10
0
•
•
•
120%
100%
m 80%
> 60%
0
40%
20%
0%
TSS Removal
• Effluent —Limit
•
•
•
•
•
otio61,
otio' otio' otio otio oti° otio otio otio otio
Ammonia (NH3-N)
Wk Avg • Mo Avg WA Limit - - - MA Limit
4.0
3.5
3.0
J 2.5
2.0
1.5
1.0
0.5
0.0
otio otio' otio otio otio oti° otio otio otio otio
o\���ti ��tio\� o\���ti h\�h�ti y�\ti�ti o�ti�\� \��ti
Summary Statistics
N 436
Avg 3.4
SD 8.0
Min 2.5
Max 128.0
Summary Statistics
N 433
Avg 98.1
SD 0.061
Min 22.1
Max 99.6%
Summary Statistics
Summer
N 597
Avg 0.74
SD 0.52
Min 0.04
Max 6.70
Winter
N 402
Avg 0.69
SD 0.53
Min 0.04
Max 4.16
Page 2 of 6 GB Perlmutter 9/23/2022

Big Buffalo WWTP Effluent Monitoring
NC0024147
1000
• Mo Avg
recal uoiirorm
Wk Avg MA Limit WA Limit
•
0-
100 M '• •• '.
o • Mom!• . • �•••
. Y•
100
•
•n. ••'•�•v�••.•' K'•
•' .�'
•
air a•
•
1 • •
oti� oti� oti� oti�' oti�' oti° otiti otiti oti� oti�
10 -
9
8
7
6
5
pH
• Effluent - - - L. Limit U. Limit
fiven#4..weivioarogsft
• •
4
O�� O�� O,� O� O� Off° O�� O'1y 0'V 01,
Temperature
Summary Statistics
N 441
Geomean 12
Min 1
Max 2420
Summary Statistics
N 999
Avg 8.5
SD 1.0
Min 5.6
Max 11.1
Summary Statistics
N 999
Avg 6.6
SD 0.2
Min 5.4
Max 7.2
Page 3 of 6 GB Perlmutter 9/23/2022

Big Buffalo WWTP
Effluent Monitoring
NC0024147
30 -
25
20
u 15
10
5
0
O",\ O� O, O, O,O 61' 61' O� O� Ol•
d
Total Phosphorus (TP)
16
14
12
10 •
w s • •• i ••• •
•• • •• • •• •• • ••
6 • • • y • • • • •
2 •• IF• •* :&'
•
• • VI il•
•
•
0 - -
••
•
•
oti� oti�' otio oti� oti° otiy otiti oti� oti�
o\\�o�ti o\���ti h\y��ti y�\ti�ti °\y��ti �\���ti 1\1P'\���ti
6000 r
Summer TP Load
Summary Statistics
N 999
Avg 20.4
SD 4.7
Min 12.0
Max 28.0
Summary Statistics
N 999
Avg 554
SD 114
Min 121
Max 881
Summary Statistics
N 268
Avg 2.29
SD 2.50
Min 0.10
Max 14.88
Page 4 of 6 GB Perlmutter 9/23/2022

Big Buffalo WWTP Effluent Monitoring NC0024147
5000
4000
0
3000
2000
1000
0
•
•
•
•• • • • •
• • •• •• •
• • • • •
• • •
•
•
NN•
O,� O�� O,O O,� Off° O1y �
AV
0
E
0
16000
14000
12000
10000
8000
6000
4000
2000
0
•
TN Load
•
•
• ••• • ••
• • •••• • •• •
• •
••~•••
oti oti oti' oti° oti° oti° otiti 61> oti
„o'
\,(0'
\co,
70 r
L
Total Copper (Cu)
Summary Statistics
N 29
Avg 1992.62
SD 1192.29
Min 152.56
Max 5251.51
Summa Statistics
N 212
Avg 4.52
SD 3.08
Min 0.83
Max 19.10
NO2+NO3
N 212
Avg 3.06
SD 2.66
Min 0.48
Max 14.96
TKN
N 213
Avg 1.57
SD 1.31
Min 0.20
Max 16.30
Summary Statistics
N 29
Avg 4640.14
SD 2590.56
Min 1959.92
Max 15223.30
Page 5 of 6 GB Perlmutter 9/23/2022

Big Buffalo WWTP
Effluent Monitoring NC0024147
ol)
50
-J 40
b
30
20
10
•
o ••••w•••M•••••••••i •••••••••••••!•••• M
oti oti oti oti° oti° oti° otiti otiti oti oti
Summary Statistics
N 48
Avg 4
SD 8
Min 2
Max 58
Page 6 of 6 GB Perlmutter 9/23/2022

Big Buffalo WWTP
Instream Monitoring NC0024147
14
12
10
- 8
E • 6
4
2
0
Dissolved Oxygen (DO)
• Upstream • Effluent Dnstream —Standard
•0 ♦ ea
oti� oti� oti� oti° oti° otiti otiti oti� oti�
35
30
25
u 20
15
10
5
0
Temperature
• Upstream 6 Effluent Dnstream —Standard
r-
im •limlig niblinn N)
• ■ + n■
o
O>�
o\���ti/�• ti �\y��ti \ti�ti o\y��ti \C�ti ��ti ��ti et\���ti
900
800
700
600
500
3 400
300
200
100
0
Conductivity
• Upstream Effluent Dnstream
■
■�
■
■ ■
■
• -. •
■
•
■
■
■ ■ NM
■
■
■
■
■
n
D him iy�- �-y•.G� Mor. _e,(•"c =n
ONE• ON•E ONE
Page 1 of 4
GB Perlmutter, 9/23/2022

Big Buffalo WWTP
Instream Monitoring NCOO24147
100000
10000
E
0
0
- 100
U
1000
10
1
Fecal Coliform
• Upstream • Effluent ♦ Dnstream
•
• • • !♦
6 •
*• • ♦• !• •• •♦
r • • •
•
♦
•
♦ •
•
oti oti' oti' oti' oti oti° o01> oti PI,
1.2
1
0.8
Sao 0.6
E
0.4
0.2
0
Ammonia Nitrogen (NH3-N)
• Upstream Effluent ♦ Dnstream
.•_•_�_•_•�•
i
•
•
.1, es • A. inn nmV Amin m!� .nna\nfripurnpiOn v,rn r�
oti o'C'b o''�' oti° oti° oti° otiti otiti oti oti
• Upstream
10
9
8
6
5
4
pH
Effluent Dnstream - L. Std U. Std
•:�ti•��•
O,A 00� 00�
Page 2 of 4
GB Perlmutter, 9/23/2022

Big Buffalo WWTP
Instream Monitoring
NCOO24147
2.5
2.0
\ 1.5
1.0
0.5
0.0
•
Total Kjeldahl Nitrogen (TKN)
• Upstream
■
w ■■■
r:
Effluent Dnstream
■
■
• rM ■■ • ■ RI• • ■ 4?■ I I
�• ■■ .. !•• ••�.IA•.
•
O, O,� OHO
����ti �\yo�ti yo\���ti �\y��ti y�\ti�ti �\y��ti '\��ti A\���ti cb\l'��ti
Total Phosphorus
• Upstream r Effluent Dnstream
4.0 -
3.5 - ■ 1
3.0 -
J 2.5 - ■
■
awn 2.0 -■■
■ • ■
1.0 - ■ ■ ■ ■ ■ ■
■
0.5 - ■ ■ ■ ■ ■ Ft ■ ■
0.0 ,,� M'� ,PAIN,,Ncnr16•■iv Mn�`��JN_nu!'IrnlvIOt)'
O�A O� 0.,
O' , O,O O,O OHO O�y O�y O1, O'1�
„,,,,I,
ev-
Page 3 of 4
GB Perlmutter, 9/23/2022

Big Buffalo WWTP
Instream Monitoring NC0024147
120
100
80
H 60
z
40
20
0
Turbidity
• Upstream Dnstream —Standard
• •
♦
♦
•
•6 ♦
••
• ♦ • a n••
r•
• • • • � ::�
r Q 0/ 114 A •
•
oti� oti�' oti�' oti� oti� otio '1> otiy oti� oti�
�\���ti �\yo�ti o\���ti �\y��ti titi�y\ 6\y��ti y\��ti A\,1?)
Page 4 of 4 GB Perlmutter, 9/23/2022

Deep
AU Name
AU ID Description
DEEP RIVER
NORTH CAROLINA 2020 INTEGRATED REPORT
Cape Fear River Basin
AU Number Classification AU LengthArea AU Units
17-(38.7)
4141 From Lee County water supply intake to a point 0.4 mile upstream of Rocky Branck
12.0 FW Miles
2020 Draft Water Quality Assessments
PARAMETER
IR CATEGORY CRITERIA STATUS
REASON FOR RATING
Water Temperature (32°C, AL, LP&CP)
Dissolved Oxygen (4 mg/I, AL, FW)
pH (6 su, AL, FW)
pH (9.0, AL, FW)
Turbidity (50 NTU, AL, FW miles)
Fecal Coliform (GM 200/400, REC, FW)
Fecal Coliform (GM 200/400, REC, FW)
1 Meeting Criteria
1 Meeting Criteria
1 Meeting Criteria
1 Meeting Criteria
1 Meeting Criteria
1 Meeting Criteria
1 Meeting Criteria
DEEP RIVER 17-(4)a
4142 From dam at Oakdale Cotton Mills, Inc. to SR 1113
WS-IV;CA:*
Meeting Criteria
Meeting Criteria
Meeting Criteria
Meeting Criteria
Meeting Criteria
with Statistical Con
with Statistical Con
with Statistical Con
with Statistical Con
with Statistical Con
Pathogen Indicator Meeting Criteria
Pathogen Indicator Meeting Criteria
2.0 FW Miles
2020 Draft Water Quality Assessments
PARAMETER
IR CATEGORY CRITERIA STATUS
REASON FOR RATING
Water Temperature (32°C, AL, LP&CP)
Dissolved Oxygen (4 mg/I, AL, FW)
pH (6 su, AL, FW)
pH (9.0, AL, FW)
NO2+NO3-N (10 mg/I, WS, WS)
Turbidity (50 NTU, AL, FW miles)
Fecal Coliform (GM 200/400, REC, FW)
1 Meeting Criteria
1 Meeting Criteria
1 Meeting Criteria
1 Meeting Criteria
1 Meeting Criteria
1 Meeting Criteria
1 Meeting Criteria
Meeting Criteria
Meeting Criteria
Meeting Criteria
Meeting Criteria
Meeting Criteria
Meeting Criteria
with Statistical Con
with Statistical Con
with Statistical Con
with Statistical Con
with Statistical Con
with Statistical Con
Pathogen Indicator Meeting Criteria
7/21/2021 NC 2020 INTEGRATED REPORT Category 5 assessments approved by EPA June 23,2021
Page 110 of 1334

MONITORING REPORT(MR) VIOLATIONS for:
Report Date: 05/31/22 Page 1 01 1
Permit: NC0024147 MRs Betweei 4 - 2017 and 5 - 2022
Facility Name: % Param Nam( %
Major Minor: %
Region: % Violation Category:Limit Violation Program Category: NPDES WW
County: % Subbasin:% Violation Action:
PERMIT: NC0024147
FACILITY: City Of Sanford - Big Buffalo WWTP
COUNTY: Lee REGION: Raleigh
Limit Violation
MONITORING UNIT OF
OUTFALL LOCATION PARAMETER VIOLATION FREQUENCY
REPORT DATE MEASURE
LIMIT
CALCULATED
VALUE Over
VIOLATION TYPE VIOLATION ACTION
09-2018 001
09-2018 001
09-2018 001
03-2019 001
03-2019 001
Effluent
Effluent
Effluent
Effluent
Effluent
pH
pH
pH
pH
pH
09/17/18 5 X week su 6 5.6 6.7 Daily Minimum Not Proceed to NOV
Reached
09/19/18 5 X week su 6 5.6 6.7 Daily Minimum Not Proceed to NOV
Reached
09/21/18 5 X week su 6 5.5 8.3 Daily Minimum Not Proceed to NOV
Reached
03/21/19 5 X week su 6 5.4 10 Daily Minimum Not Proceed to NOV
Reached
03/22/19 5 X week su 6 5.4 10 Daily Minimum Not Proceed to NOV
Reached

i a 0
Whole Effluent Toxicity Testing and Self Monitoring Summary
U
0
O
Feb May Aug Nov
m
0
L▪ )
C
co
0]
cu
00
C
In
E
to O.
L
o
U c
O
T
C
0
O
U
NC0038300/001
S.S. Mobile Home Park
chr lim: 90%
O
O
a\ -I
a -I
C
.00
m
O
• d D_ D D
C
O O O O O
U
0
O
Feb May Aug Nov
0
O
0
}
N
co
cu
00
C
•H
C
0
z0 c
0
Z
T
O
U
chr lim: 34%
O
-1
O
a\ -I
0
a -I
C
.00
m
LL
0-
0 2
H
2
� 2 �
• o_ z
U
0
UI
0
Mar Jun Sep Dec
O
}
C
•
(Ca
0
0
K
C
0
U
NC0023884/001
Salisbury WWTP
7Q10: 263.5
NonComp: Single
chr lim: 5.3%; exp 20
u-
a
N
n
a)
U
O
1 G 0 0 0
LL
CO 01 0
O O O O
U
0
O
Jan Apr Jul Oct
NC0086991/001
Sanchez Drive WTP
0
0)
LL
Cerio7dPF Monit: 90
0
O
C
.Ea
CO
u-
a
n
0)
U
1 a D_ D_ D_
C
L
U
0
O
Mar Jun Sep Dec
1
▪ 1
L)
C
(0
m
0
K
O
tie
cc
NC0024147/001
Sanford -Big Buffalo WWTP
7Q10: 16.8
NonComp: Single
chr lim: 12MGD @ 45
O
0
Page 94 of 117
Legend: P= Fathead minnow (Pimohales oromelasl. H=No Flow (facility is active). s = Solit test between Certified Labs

United States Environmental Protection Agency
E PA Washington, D.C. 20460
Water Compliance Inspection Report
Form Approved.
OMB No. 2040-0057
Approval expires 8-31-98
Section A: National Data System Coding (i.e., PCS)
Transaction Code NPDES yr/mo/day Inspection
1 IN I 2 IL I 3 I NC0024147 111 121 21/06/01 117
Type
1810I
I I I I I
Inspector Fac Type
19I S I 2011
211111 I I I I I I II I I I I I I I I I I I I I I I I I
I II
I I I I I P6
Inspection Work Days Facility Self -Monitoring Evaluation Rating B1 QA Reserved
671 I 70I I 711 172 I N I 73I 1 74 71
I I
I I I I I I 180
Section B: Facility Data
Name and Location of Facility Inspected (For Industrial Users discharging to POTW, also include
POTW name and NPDES permit Number)
Big Buffalo WWTP
5327 Iron Furnace Rd
Sanford NC 27330
Entry Time/Date
01:OOPM 21/06/01
Permit Effective Date
18/05/01
Exit Time/Date
03:30PM 21/06/01
Permit Expiration Date
22/09/30
Name(s) of Onsite Representative(s)/Titles(s)/Phone and Fax Number(s)
///
Scott A Siletzky/ORC/919-775-8305/
Other Facility Data
Name, Address of Responsible Official/Title/Phone and Fax Number
Contacted
Paul Martin Weeks,PO Box 3729 Sanford NC 273303729/City
Engineer/919-777-1119/9197748179 No
Section C: Areas Evaluated During Inspection (Check only those areas evaluated)
Permit Flow Measurement Operations & Maintenar Records/Reports
Sludge Handling Dispo: Effluent/Receiving Wate Laboratory
Section D: Summary of Finding/Comments (Attach additional sheets of narrative and checklists as necessary)
(See attachment summary)
Name(s) and Signature(s) of Inspector(s) Agency/Office/Phone and Fax Numbers Date
Jason T Robinson DWR/RRO WQ/919-791-4200/
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# 1

3I
NPDES yr/mo/day
NC0024147 111 121 21/06/01
117
Inspection Type
18 [j
(Cont.)
1
Section D: Summary of Finding/Comments (Attach additional sheets of narrative and checklists as necessary)
On Tuesday, June 1, 2020, Jason Robinson of the Raleigh Regional Office conducted a compliance
evaluation inspection of the treatment facilities located at the Big Buffalo WWTP. The purpose of this
inspection was to ensure compliance with the subject NPDES permit. During the inspection, the
presence and cooperation of Mr. Scott Siletzky, Operator in Responsible Charge (ORC) and Mr. Dale
Deaton, Lab Supervisor were helpful and appreciated.
The City of Sanford Big Buffalo WWTP is located at 5327 Iron Furnace Road, Sanford, NC. The
WW-4 facility is permitted and authorized to discharge 12 MGD of treated wastewater through Outfall
001 into the Deep River.
This NPDES compliance evaluation inspection consisted of the following:
• Review of the NPDES permit;
• Review of the owner/facility information;
• Review of April 2019 —April 2021 monitoring data;
• Review of April 2019 —April 2021 compliance history;
• On -site inspection of the laboratory;
• On -site inspection of the wastewater treatment units
Findings during the pre -inspection file review were as follows:
1. The NPDES permit was issued effective on May 1, 2018, and will expire on September 30, 2022.
2. As listed in the subject permit, the treatment components include: 4 mechanical bar screens and
1 manual bar screen; dual grit collection system; equalization tank; aeration basins; 5 clarifiers;
denitrification filters; ultraviolet disinfection system (4 channels); alum and supplemental carbon
facility; gravity -belt thickeners; 5 sludge storage tanks; and standby electrical generation. The
influent pump station is not listed in the permit and should be included in the next permit application
submittal and issued permit.
3. For the review period April 2019 —April 2021, no DMR violations were detected and no
enforcement actions (Notices of Deficiency, Notices of Violation, or Civil Penalty Assessments) were
issued to the City. In addition, the facility has been compliant with its Chronic Toxicity permit limit and
monitoring requirements, which is required in the months of March, June, September and December.
An Effluent Pollutant Scan is required to be done three times during the permit cycle. The pollutant
scans were done on June 13, 2018, March 12, 2019 and December 15, 2020.
4. As required by North Carolina General Statute § 143-215.1C(a), the City has prepared and made
available to its customers the wastewater annual report for fiscal year 2020. The report summarizes
the performance of the City's treatment facilities and the extent to which any permit requirements
have been violated.
5. The plant's influent pump station was significantly affected during Hurricane Florence in
September 2018. The entire area was inundated by flood waters from the nearby Big Buffalo Creek
and Deep River. Until the floodwater receded, all water inside of the earthen berm structure was sent
through the treatment plant. DWR staff performed site visits on September 21 st and 26th, 2018.
Work was ongoing on the pump station and surrounding berms during the inspection.
Findings during the inspection were as follows:
6. The operator's log and supporting analytical documentation were consistent and up to date.
7. The inspector compared December 2020 and February 2021 DMR data against the bench lab
data and the contract labs (Environment 1 & Meritech) analytical data. No discrepancies were noted.
8. The laboratory (certification number 137) is certified for and self -reports monitoring data for most
parameters. Others are done by Environment 1 (certification number 10). Toxicityanalysis is done by
Meritech (lab number 165). An inspection of the meter calibration logs, standards, buffer expiration
dates and incubator temperatures (fecal and BOD) showed the laboratory to be compliant with
record -keeping requirements. The thermometers used are calibrated to NSIT standards quarterly.
9. At the time of inspection, work was still ongoing at the influent pump station and surrounding berm
Page# 2

Permit: NC0024147
Inspection Date: 06/01/2021
Owner - Facility: Big Buffalo WWTP
Inspection Type: Compliance Evaluation
due to damages and to rectify flooding sustained during Hurricane Florence in September of 2018.
There are 7 total influent pump stations.
10. The EQ basin was not in use during the time of the visit.
11. Clarifiers 1-4 were in operation, while 5 was down for repair. Plant staff measured the sludge
level in clarifier #3 using a graduated sludge judge. The inspector observed the measured sludge
level at 1.5 ft. The ORC stated the clarifiers are 15-ft. deep.
12. Three on -site generators power the site and are exercised weekly.
13. Synagro pump and removes sludge from the digester.
14. The inspector was able to observe/inspect the outfall. The right of way was maintained and the
effluent observed was clear and free of solids and excess foam.
Other than the influent pump station and surrounding berm that are under construction, the overall
condition of the subject facility was compliant with the NPDES permit requirements as observed on
the day of the inspection. Please make sure to include the influent pump station in your next permit
renewal application
Page# 3

Permit: NC0024147
Inspection Date: 06/01/2021
Owner - Facility: Big Buffalo WWTP
Inspection Type: Compliance Evaluation
Permit Yes No NA NE
(If the present permit expires in 6 months or less). Has the permittee submitted a new ❑ ❑ ❑ ❑
application?
Is the facility as described in the permit? • ❑ ❑ ❑
# Are there any special conditions for the permit? El • El El
Is access to the plant site restricted to the general public? • ❑ ❑ ❑
Is the inspector granted access to all areas for inspection? • ❑ ❑ ❑
Comment: -
Record Keeping
Are records kept and maintained as required by the permit?
Is all required information readily available, complete and current?
Are all records maintained for 3 years (lab. reg. required 5 years)?
Are analytical results consistent with data reported on DMRs?
Is the chain -of -custody complete?
Dates, times and location of sampling
Name of individual performing the sampling
Results of analysis and calibration
Dates of analysis
Name of person performing analyses
Transported COCs
Are DMRs complete: do they include all permit parameters?
Has the facility submitted its annual compliance report to users and DWQ?
(If the facility is = or > 5 MGD permitted flow) Do they operate 24/7 with a certified
operator on each shift?
Is the ORC visitation log available and current?
Is the ORC certified at grade equal to or higher than the facility classification?
Is the backup operator certified at one grade less or greater than the facility
classification?
Is a copy of the current NPDES permit available on site?
Facility has copy of previous year's Annual Report on file for review?
Comment:
Laboratory
Are field parameters performed by certified personnel or laboratory?
Yes No NA NE
• ❑ ❑ ❑
• ❑ ❑ ❑
• ❑ ❑ ❑
•
•
•
•
• ❑ ❑ ❑
• ❑ ❑ ❑
• ❑ ❑ ❑
• ❑ ❑ ❑
Yes No NA NE
Page# 4

Permit: NC0024147
Inspection Date: 06/01/2021
Owner - Facility: Big Buffalo WWTP
Inspection Type: Compliance Evaluation
Laboratory
Are all other parameters(excluding field parameters) performed by a certified lab?
# Is the facility using a contract lab?
# Is proper temperature set for sample storage (kept at less than or equal to 6.0
degrees Celsius)?
Incubator (Fecal Coliform) set to 44.5 degrees Celsius+/- 0.2 degrees?
Incubator (BOD) set to 20.0 degrees Celsius +/- 1.0 degrees?
Comment:
Yes No NA NE
• ❑ ❑ ❑
• ❑ ❑ ❑
• ❑ ❑ ❑
Operations & Maintenance Yes No NA NE
Is the plant generally clean with acceptable housekeeping? • ❑ ❑ ❑
Does the facility analyze process control parameters, for ex: MLSS, MCRT, Settleable MODE
Solids, pH, DO, Sludge Judge, and other that are applicable?
Comment:
Pump Station - Influent
Is the pump wet well free of bypass lines or structures?
Is the wet well free of excessive grease?
Are all pumps present?
Are all pumps operable?
Are float controls operable?
Is SCADA telemetry available and operational?
Is audible and visual alarm available and operational?
Yes No NA NE
• ❑ ❑ ❑
• ❑ ❑ ❑
• ❑ ❑ ❑
• ❑ ❑ ❑
• ❑ ❑ ❑
• ❑ ❑ ❑
• ❑ ❑ ❑
Comment: Construction still ongoing due to damages caused by Hurrican Florence in 2018
Bar Screens Yes No NA NE
Type of bar screen
a.Manual ❑
b.Mechanical •
Are the bars adequately screening debris? • ❑ ❑ ❑
Is the screen free of excessive debris? • ❑ ❑ ❑
Is disposal of screening in compliance? • ❑ ❑ ❑
Is the unit in good condition? • ❑ ❑ ❑
Comment: 4 mechanical, 1 manual
Page# 5

Permit: NC0024147
Inspection Date: 06/01/2021
Owner - Facility: Big Buffalo WWTP
Inspection Type: Compliance Evaluation
Grit Removal
Type of grit removal
a.Manual
b.Mechanical
Is the grit free of excessive organic matter?
Is the grit free of excessive odor?
# Is disposal of grit in compliance?
Comment:
Flow Measurement - Influent
# Is flow meter used for reporting?
Is flow meter calibrated annually?
Is the flow meter operational?
(If units are separated) Does the chart recorder match the flow meter?
Comment: Effluent flow use for reporting
Yes No NA NE
•
• ❑ ❑ ❑
• ❑ ❑ ❑
• ❑ ❑ ❑
Yes No NA NE
❑ • ❑ ❑
• ❑ ❑ ❑
• ❑ ❑ ❑
• ❑ ❑ ❑
Aeration Basins Yes No NA NE
Mode of operation Ext. Air
Type of aeration system Diffused
Is the basin free of dead spots? • ❑ ❑ ❑
Are surface aerators and mixers operational? • ❑ ❑ ❑
Are the diffusers operational? • ❑ ❑ ❑
Is the foam the proper color for the treatment process? • ❑ ❑ ❑
Does the foam cover less than 25% of the basin's surface? • ❑ ❑ ❑
Is the DO level acceptable? ❑ ❑ ❑ •
Is the DO level acceptable?(1.0 to 3.0 mg/I) ❑ ❑ ❑ •
Comment:
Nutrient Removal Yes No NA NE
# Is total nitrogen removal required? • ❑ ❑ ❑
# Is total phosphorous removal required? • ❑ ❑ ❑
Type Biological
# Is chemical feed required to sustain process? • ❑ ❑ ❑
Is nutrient removal process operating properly? • ❑ ❑ ❑
Page# 6

Permit: NC0024147
Inspection Date: 06/01/2021
Owner - Facility: Big Buffalo WWTP
Inspection Type: Compliance Evaluation
Nutrient Removal
Comment:
Secondary Clarifier
Is the clarifier free of black and odorous wastewater?
Is the site free of excessive buildup of solids in center well of circular clarifier?
Are weirs level?
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: Clarifiers 1-4 operational, 5 ongoing cnostruction.
Sludge measured in 3 (-1.5 feet of 15 feet)
Pumps-RAS-WAS
Are pumps in place?
Are pumps operational?
Are there adequate spare parts and supplies on site?
Comment:
Yes No NA NE
Yes No NA NE
• ❑ ❑ ❑
• ❑ ❑ ❑
• ❑ ❑ ❑
• ❑ ❑ ❑
• ❑ ❑ ❑
• ❑ ❑ ❑
Yes No NA NE
• ❑ ❑ ❑
• ❑ ❑ ❑
❑ ❑ ❑ •
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? ■ El ❑ ❑
Is the filter free of growth? • El El El
Is the air scour operational? • ❑ ❑ ❑
Is the scouring acceptable? • El El El
Is the clear well free of excessive solids and filter media? ■ ❑ El El
Comment:
Page# 7

Permit: NC0024147
Inspection Date: 06/01/2021
Owner - Facility: Big Buffalo WWTP
Inspection Type: Compliance Evaluation
Disinfection - UV Yes No NA NE
Are extra UV bulbs available on site? ❑ ❑ ❑ •
Are UV bulbs clean? ❑ ❑ El •
Is UV intensity adequate? ❑ ❑ El •
Is transmittance at or above designed level? ❑ ❑ ❑ •
Is there a backup system on site? • ❑ ❑ ❑
Is effluent clear and free of solids? • ❑ ❑ ❑
Comment:
Effluent Pipe
Is right of way to the outfall properly maintained?
Are the receiving water free of foam other than trace amounts and other debris?
If effluent (diffuser pipes are required) are they operating properly?
Comment:
Standby Power
Is automatically activated standby power available?
Is the generator tested by interrupting primary power source?
Is the generator tested under load?
Was generator tested & operational during the inspection?
Do the generator(s) have adequate capacity to operate the entire wastewater site?
Is there an emergency agreement with a fuel vendor for extended run on back-up
power?
Is the generator fuel level monitored?
Comment: _
Flow Measurement - Effluent
# Is flow meter used for reporting?
Is flow meter calibrated annually?
Is the flow meter operational?
(If units are separated) Does the chart recorder match the flow meter?
Comment:
Yes No NA NE
• ❑ ❑ ❑
Yes No NA NE
• ❑ ❑ ❑
• ❑ ❑ ❑
• ❑ ❑ ❑
• ❑ ❑ ❑
• ❑ ❑ ❑
Yes No NA NE
• ❑ ❑ ❑
Page# 8

United States Environmental Protection Agency
E PA Washington, D.C. 20460
Water Compliance Inspection Report
Form Approved.
OMB No. 2040-0057
Approval expires 8-31-98
Section A: National Data System Coding (i.e., PCS)
Transaction Code NPDES yr/mo/day Inspection
1 IN I 2 LI 3 I NC0024147 111 121 21/09/17 117
Type
1811
IIIIIIIIIII
Inspector Fac Type
19I S I 2011
21IIIIII IIIIIIIIIIIIIIIIII I IIIIII
P6
Inspection Work Days Facility Self -Monitoring Evaluation Rating B1 QA Reserved
671 I 70I I 711 172 I N I 731 1 74 71
I I
I I I I I I 180
Section B: Facility Data
Name and Location of Facility Inspected (For Industrial Users discharging to POTW, also include
POTW name and NPDES permit Number)
Big Buffalo WWTP
5327 Iron Furnace Rd
Sanford NC 27330
Entry Time/Date
10:OOAM 21/09/17
Permit Effective Date
18/05/01
Exit Time/Date
02:30PM 21/09/17
Permit Expiration Date
22/09/30
Name(s) of Onsite Representative(s)/Titles(s)/Phone and Fax Number(s)
///
Scott A Siletzky/ORC/919-775-8305/
Other Facility Data
Name, Address of Responsible Official/Title/Phone and Fax Number
Contacted
Paul Martin Weeks,PO Box 3729 Sanford NC 273303729/City
Engineer/919-777-1119/9197748179 No
Section C: Areas Evaluated During Inspection (Check only those areas evaluated)
Pretreatment
Section D: Summary of Finding/Comments (Attach additional sheets of narrative and checklists as necessary)
(See attachment summary)
Name(s) and Signature(s) of Inspector(s) Agency/Office/Phone and Fax Numbers Date
Cheng Zhang DWR/RRO WQ/919-791-4200/
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# 1

NPDES yr/mo/day
31 NC0024147 111 121 21/09/17
117
Inspection Type
18 {j
1
Section D: Summary of Finding/Comments (Attach additional sheets of narrative and checklists as necessary)
Page# 2

Permit: NC0024147
Inspection Date: 09/17/2021
Owner - Facility: Big Buffalo WWTP
Inspection Type: Pretreatment Audit
Yes No NA NE
Page# 3

United States Environmental Protection Agency
E PA Washington, D.C. 20460
Water Compliance Inspection Report
Form Approved.
OMB No. 2040-0057
Approval expires 8-31-98
Section A: National Data System Coding (i.e., PCS)
Transaction Code NPDES yr/mo/day Inspection
1 IN I 2 LI 3 I NC0024147 111 121 22/03/15 117
Type
181 R I
I11IIIIIII1
Inspector Fac Type
19 I S I 2011
211I1I1I I111I1IIIII I11111I I IIIIII
P6
Inspection Work Days Facility Self -Monitoring Evaluation Rating B1 QA Reserved
671 I 70 I3 I 71 I D 172 I N I 73 74 71
I I 1
I I I I I I 180
Section B: Facility Data
Name and Location of Facility Inspected (For Industrial Users discharging to POTW, also include
POTW name and NPDES permit Number)
Big Buffalo WWTP
5327 Iron Furnace Rd
Sanford NC 27330
Entry Time/Date
09:OOAM 22/03/15
Permit Effective Date
18/05/01
Exit Time/Date
09:20AM 22/03/15
Permit Expiration Date
22/09/30
Name(s) of Onsite Representative(s)/Titles(s)/Phone and Fax Number(s)
///
Scott A Siletzky/ORC/919-775-8305/
Other Facility Data
Name, Address of Responsible Official/Title/Phone and Fax Number
Contacted
Paul Martin Weeks,PO Box 3729 Sanford NC 273303729/City
Engineer/919-777-1119/9197748179 No
Section C: Areas Evaluated During Inspection (Check only those areas evaluated)
Other
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
Cheng Zhang DWR/RRO WQ/919-791-4200/
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# 1

31
NPDES yr/mo/day
N C 0024147 111 121 22/0 3/ 15
I17
Inspection Type
18 LB]
1
Section D: Summary of Finding/Comments (Attach additional sheets of narrative and checklists as necessary)
Two effluent composite samples were collected on March 15 and 17, 2022, and were used for
Ceriodaphnia dubia chronic pass/fail test by staff at DWR Aquatic Toxicity Branch. The test result was
PASS.
Page# 2

Permit: NC0024147
Inspection Date: 03/15/2022
Owner - Facility: Big Buffalo WWTP
Inspection Type: Bioassay Compliance
Other
Comment:
Yes No NA NE
Page# 3

NH3/TRC WLA Calculations
City of Sanford - Big Buffalo WWTP
PermitNo. NC0024147
Prepared By: Gary Perlmutter
Enter Design Flow (MGD): 12
Enter s7Q10 (cfs): 22.5
Enter w7Q10 (cfs): 33.6
Total Residual Chlorine (TRC)
Daily Maximum Limit (ug/I)
s7Q10 (CFS)
DESIGN FLOW (MGD)
DESIGN FLOW (CFS)
STREAM STD (UG/L)
Upstream Bkgd (ug/I)
IWC (%)
Allowable Conc. (ug/I)
Fecal Coliform
Monthly Average Limit:
(If DF >331; Monitor)
(If DF<331; Limit)
Dilution Factor (DF)
22.5
12
18.6
17.0
0
45.26
38
Ammonia (Summer)
Monthly Average Limit (mg NH3-N/I)
s7Q10 (CFS)
DESIGN FLOW (MGD)
DESIGN FLOW (CFS)
STREAM STD (MG/L)
Upstream Bkgd (mg/I)
IWC (%)
Allowable Conc. (mg/I)
Ammonia (Winter)
Monthly Average Limit (mg NH3-N/I)
w7Q10 (CFS)
200/100mI DESIGN FLOW (MGD)
DESIGN FLOW (CFS)
STREAM STD (MG/L)
2.21 Upstream Bkgd (mg/I)
IWC (%)
Allowable Conc. (mg/I)
Total Residual Chlorine
1. Cap Daily Max limit at 28 ug/I to protect for acute toxicity
Ammonia (as NH3-N)
1. If Allowable Conc > 35 mg/I, Monitor Only
2. Monthly Avg limit x 3 = Weekly Avg limit (Municipals); capped at 35 mg/I
3. Monthly Avg limit x 5 = Daily Max limit (Non-Munis); capped at 35 mg/I
22.5
12
18.6
1.0
0.22
45.26
1.9
33.6
12
18.6
1.8
0.22
35.63
4.7
Fecal Coliform
1. Monthly Avg limit x 2 = 400/100 ml = Weekly Avg limit (Municipals) = Daily Max limit (Non -Muni)

Freshwater RPA - 95% Probability/95% Confidence Using Metal Translators
MAXIMUM DATA POINTS = 58
REQUIRED DATA ENTRY
Table 1. Project Information
Facility Name
WWTP/WTP Class
NPDES Permit
Outfall
Flow, Qw (MGD)
Receiving Stream
HUC Number
Stream Class
I. CHECK IF HQW OR ORW WQS
Big Buffalo WWTP
Grade IV
NC0024147
001
12.000
Deep River
03030003
C
Apply WS Hardness WQC
7Q10s (cfs)
7Q1Ow (cfs)
30Q2 (cfs)
QA (cfs)
1Q10s (cfs)
22.50
33.60
1260.00
I 18.56 1
Effluent Hardness
Upstream Hardness
Combined Hardness Chronic
Combined Hardness Acute
65.31 mg/L (Avg)
32.16 mg/L (Avg)
47.16 mg/L
48.75 mg/L
Data source: submitted DMRs; instream hardness
submitted with renewal application.
Data Source(s)
CHECK TO APPLY MODEL
Table 2. Parameters of Concern
Par01
Par02
Par03
Par04
Par05
Par06
Par07
Par08
Par09
Par10
Par11
Par12
Par13
Par14
Par15
Par16
Par17
Par18
Par19
Par20
Par21
Par22
Par23
Par24
Name
WQS
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
0.9531
FW
5.8029
ug/L
Chlorides
Aquatic Life
NC
230
FW
Chlorinated Phenolic Compounds
Water Supply
NC
1
A
ug/L
4 Total Phenolic Compounds
Aquatic Life
NC
300
A
ug/L
Chromium III
Aquatic Life
NC
197.9962
FW
1564.0418
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
13.5553
FW
19.6483
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
5.9846
FW
159.3401
ug/L
Mercury
Aquatic Life
NC
12
FW
0.5
ng/L
Molybdenum
Human Health
NC
2000
HH
ug/L
Nickel
Aquatic Life
NC
63.6959
FW
589.8037
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
0.9349
ug/L
Zinc
Aquatic Life
NC
216.9965
FW
221.3719
ug/L
24147 Freshwater RPA, input
9/23/2022

REASONABLE POTENTIAL ANALYSIS
H1
Effluent Hardness
Date Data BDL=1/2DL Results
1 4/3/2018 77 77 Std Dev.
2 5/1/2018 60 60 Mean
3 6/5/2018 84 84 C.V.
4 7/2/2018 80 80
5 8/7/2018 100 100 10th Per value
6 9/4/2018 67 67 Average Value
7 10/1/2018 60 60 Max. Value
8 11/6/2018 68 68
9 12/4/2018 69 69
10 1/4/2019 55 55
11 2/5/2019 59 59
12 3/5/2019 41 41
13 4/2/2019 71 71
14 5/6/2019 63 63
15 6/3/2019 87 87
16 7/1/2019 71 71
17 8/6/2019 63 63
18 9/10/2019 74 74
19 10/1/2019 96 96
20 11/5/2019 74 74
21 12/3/2019 69 69
22 1/6/2020 52 52
23 2/3/2020 56 56
24 3/3/2020 54 54
25 4/6/2020 61 61
26 5/4/2020 46 46
27 6/2/2020 50 50
28 7/7/2020 55 55
29 8/3/2020 54 54
30 9/1/2020 69 69
31 10/6/2020 60 60
32 11/3/2020 68 68
33 12/1/2020 54 54
34 1/5/2021 48 48
35 2/2/2021 48 48
36 3/2/2021 52 52
37 4/6/2021 62 62
38 5/4/2021 74 74
39 6/1/2021 75 75
40 7/6/2021 70 70
41 8/3/2021 65 65
42 9/7/2021 67 67
43 10/12/2021 67 67
44 11/8/2021 81 81
45 12/7/2021 76 76
46 1/4/2022 70 70
47 2/1/2022 54 54
48 3/1/2022 59 59
49
50
51
52
53
54
55
56
57
58
Use"PASTE SPECIAL
Values"then "COPY".
Maximum data points
= 50
H2
Upstream Hardness
12.4954
65.3125
0.1913
48
51.40 mg/L
65.31 mg/L
100.00 mg/L
Date Data BDL=1/2DL Results
24 Std Dev.
30 Mean
30 C.V.
30 n
28 10th Per value
36 Average Value
36 Max. Value
26
30
30
30
33
34
28
37
32
34
39
44
6/1/2020 24
7/2/2020 30
8/3/2020 30
9/1/2020 30
10/5/2020 28
11/3/2020 36
12/9/2020 36
1/11/2021 26
2/1/2021 30
3/1/2021 30
4/5/2021 30
5/3/2021 33
6/1/2021 34
7/6/2021 28
8/2/2021 37
9/2/2021 32
10/1/2021 34
11/1/2021 39
12/2/2021 44
Use 'PASTE SPECIAL
Values" then "COPY".
Maximum data points
= 58
4.7989
32.1579
0.1492
19
27.60 mg/L
32.16 mg/L
44.00 mg/L
24147 Freshwater RPA, data
9/23/2022

REASONABLE POTENTIAL ANALYSIS
Par01 & Paro2
Arsenic
Date
1 4/3/2018
2 5/1/2018
3 6/5/2018
4 7/2/2018
5 8/7/2018 < 3
6 9/4/2018 < 3
7 10/1/2018 < 3
8 11/6/2018 < 3
9 12/4/2018 < 3
10 1/4/2019 < 3
11 2/5/2019 < 3
12 3/5/2019 < 3
13 4/2/2019 < 3
14 5/6/2019 < 3
15 6/3/2019 < 3
16 7/1/2019 < 3
17 8/6/2019 < 3
18 9/10/2019 < 3
19 10/1/2019 < 3
20 11/5/2019 < 3
21 12/3/2019 < 3
22 1/6/2020 < 3
23 2/3/2020 < 2
24 3/3/2020 < 2
25 4/6/2020 < 2
26 5/4/2020 < 2
27 6/2/2020 < 2
28 7/7/2020 < 2
29 8/3/2020 < 2
30 9/1/2020 < 2
31 10/6/2020 < 2
32 11/3/2020 < 2
33 12/1/2020 < 2
34 1/5/2021 < 2
35 2/2/2021 < 2
36 3/2/2021 < 2
37 4/6/2021 < 2
38 5/4/2021 < 2
39 6/1/2021 < 2
40 7/6/2021 < 2
41 8/3/2021 < 2
42 9/7/2021 < 2
43 10/12/2021 < 2
44 11/8/2021 < 2
45 12/7/2021 < 2
46 1/4/2022 < 2
47 2/1/2022 < 2
48 3/1/2022 < 2
49
50
51
52
53
54
55
56
57
58
Data BDL=1/2DL Results
< 2 1 Std Dev.
< 3 1.5 Mean
< 3 1.5 C.V.
< 3 1.5 n
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
Mult Factor =
Max. Value
Max. Pred Cw
Use"PASTE SPECIAL
Values"then "COPY".
Maximum data points
= 50
Par03
Beryllium
0.2507
1.2188
0.2057
48
1.02
1.5 ug/L
1.5 ug/L
Date Data BDL=1/2DL Results
1 6/13/2018 < 5 2.5 Std Dev.
2 3/12/2019 < 5 2.5 Mean
3 10/15/2020 < 5 2.5 C.V. (default)
4 9/21/2021 < 5 2.5 n
5
6 Mull Factor =
7 Max. Value
8 Max. Pred Cw
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
Use 'PASTE SPECIAL
Values" then "COPY".
Maximum data points
= 58
0.0000
2.5000
0.6000
4
2.59
2.50 ug/L
6.48 ug/L
24147 Freshwater RPA, data
9/23/2022

REASONABLE POTENTIAL ANALYSIS
Par04
Cadmium
Date Data BDL=1/2DL Results
1 4/3/2018 < 0.5 0.25 Std Dev.
2 5/1/2018 < 0.5 0.25 Mean
3 6/5/2018 < 0.5 0.25 C.V.
4 7/2/2018 < 0.5 0.25 n
5 8/7/2018 < 0.5 0.25
6 9/4/2018 < 0.5 0.25 MuIt Factor =
7 10/1/2018 < 0.5 0.25 Max. Value
8 11/6/2018 < 0.5 0.25 Max. Pred Cw
9 12/4/2018 < 0.5 0.25
10 1/4/2019 < 0.5 0.25
2/5/2019 < 0.5 0.25
12 3/5/2019 < 0.5 0.25
13 4/2/2019 < 0.5 0.25
14 5/6/2019 < 0.5 0.25
15 6/3/2019 < 0.5 0.25
16 7/1/2019 < 0.5 0.25
17 8/6/2019 < 0.5 0.25
18 9/10/2019 < 0.5 0.25
19 10/1/2019 < 0.5 0.25
20 11/5/2019 < 0.5 0.25
21 12/3/2019 < 0.5 0.25
22 1/6/2020 < 0.5 0.25
23 2/3/2020 < 0.5 0.25
24 3/3/2020 < 0.5 0.25
25 4/6/2020 < 0.5 0.25
26 5/4/2020 < 0.5 0.25
27 6/2/2020 < 0.5 0.25
28 7/7/2020 < 0.5 0.25
29 8/3/2020 < 0.5 0.25
30 9/1/2020 < 0.5 0.25
31 10/6/2020 < 0.5 0.25
32 11/3/2020 < 0.5 0.25
33 12/1/2020 < 0.5 0.25
34 1/5/2021 < 0.5 0.25
35 2/2/2021 < 0.5 0.25
36 3/2/2021 < 0.5 0.25
37 4/6/2021 < 0.5 0.25
38 5/4/2021 < 0.5 0.25
39 6/1/2021 < 0.5 0.25
40 7/6/2021 < 0.5 0.25
41 8/3/2021 < 0.5 0.25
42 9/7/2021 < 0.5 0.25
43 10/12/2021 < 0.5 0.25
44 11/8/2021 < 0.5 0.25
45 12/7/2021 < 0.5 0.25
46 1/4/2022 < 0.5 0.25
47 2/1/2022 < 0.5 0.25
48 3/1/2022 < 0.5 0.25
49
50
51
52
53
54
55
56
57
58
Use"PASTE SPECIAL
Values"then "COP)'.
Maximum data pants
= 50
Par05
Chlorides
0.0000
0.2500
0.0000
48
1.00
0.250 ug/L
0.250 ug/L
1
2
3
4
5
6
7
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
Date Data
4/3/2018 82
5/1/2018 70
6/5/2018 49
7/2/2018 98
8/7/2018 63
9/4/2018 88
10/1/2018 50
11/6/2018 48
12/4/2018 45
1/4/2019 44
2/5/2019 54
3/5/2019 34
4/2/2019 58
5/6/2019 65
6/3/2019 97
7/1/2019 74
8/6/2019 82
9/10/2019 91
10/1/2019 104
11/5/2019 75
12/3/2019 96
1/6/2020 37
2/3/2020 63
3/3/2020 90
4/6/2020 63
5/4/2020 67
6/2/2020 79
7/7/2020 69
8/3/2020 64
9/1/2020 77
10/6/2020 89
11/3/2020 105
12/1/2020 30
1/5/2021 22
2/2/2021 45
3/2/2021 46
4/6/2021 63
5/4/2021 78
6/1/2021 77
7/6/2021 66
8/3/2021 83
9/7/2021 96
10/12/2021 50
11/8/2021 86
12/7/2021 108
1/4/2022 29
2/1/2022 56
3/1/2022 71
BDL=1/2DL Results
82 Std Dev.
70 Mean
49 C.V.
98 n
63
88 Mull Factor =
50 Max. Value
48 Max. Pred Cw
45
44
54
34
58
65
97
74
82
91
104
75
96
37
63
90
63
67
79
69
64
77
89
105
30
22
45
46
63
78
77
66
83
96
50
86
108
29
56
71
Use PASTE SPECIAL.
Values" men "COPr' .
Maximum data points = 58
21.7055
68.3
0.3180
48
1.0
108.0 mg/L
111.2 mg/L
24147 Freshwater RPA, data
9/23/2022

REASONABLE POTENTIAL ANALYSIS
Par06
Chlorinated Phenolic Compounds
Date Data BDL=1/2DL Results
Std Dev.
Mean
C.V.
Use"PASTE SPECIAL
Values"then "COPY".
Maximum data points
= 50
Par07
Total Phenolic Compounds
NO DATA
NO DATA
NO DATA
0
Mult Factor = N/A
Max. Value N/A ug/L
Max. Pred Cw N/A ug/L
Date Data BDL=1/2DL Results
6/13/2018 32
3/12/2019 < 10
10/15/2020 < 10
9/21/2021 16
Use 'PASTE SPECIAL
Values" then "COPY".
Maximum data points
= 58
32 Std Dev. 12.7671
5 Mean 14.5000
5 C.V. (default) 0.6000
16 n 4
Mult Factor = 2.59
Max. Value 32.0 ug/L
Max. Pred Cw 82.9 ug/L
24147 Freshwater RPA, data
9/23/2022

REASONABLE POTENTIAL ANALYSIS
Par08
Chromium III
Date Data BDL=1/2DL Results
Std Dev.
Mean
C.V.
Use"PASTE SPECIAL
Values"then "COPY".
Maximum data points
= 50
Par09
Chromium VI
NO DATA
NO DATA
NO DATA
0
Mult Factor = N/A
Max. Value N/A pg/L
Max. Pred Cw N/A pg/L
Use "PASTE SPECIAL.
Values" then "COPY".
Maximum data points
= 58
Date Data BDL=1/2DL Results
1 Std Dev. NO DATA
2I Mean NO DATA
3 C.V. NO DATA
Mull Factor =
Max. Value
Max. Pred Cw N/A
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
24147 Freshwater RPA, data
9/23/2022

REASONABLE POTENTIAL ANALYSIS
Par10
Chromium, Total
Date Data BDL=1/2DL Results
1 4/3/2018 < 5 2.5 Std Dev.
2 5/1/2018 < 5 2.5 Mean
3 6/5/2018 < 5 2.5 C.V.
4 7/2/2018 • 5 2.5 n
5 8/7/2018 • 5 2.5
6 9/4/2018 < 5 2.5 MuIt Factor =
7 10/1/2018 • 5 2.5 Max. Value
8 11/6/2018 • 5 2.5 Max. Pred Cw
9 12/4/2018 • 5 2.5
10 1/4/2019 • 5 2.5
11 2/5/2019 • 5 2.5
12 3/5/2019 < 5 2.5
13 4/2/2019 • 5 2.5
14 5/6/2019 • 5 2.5
15 6/3/2019 • 5 2.5
16 7/1/2019 < 5 2.5
17 8/6/2019 • 5 2.5
18 9/10/2019 • 5 2.5
19 10/1/2019 • 5 2.5
20 11/5/2019 < 5 2.5
21 12/3/2019 • 5 2.5
22 1/6/2020 • 5 2.5
23 2/3/2020 • 5 2.5
24 3/3/2020 • 5 2.5
25 4/6/2020 < 5 2.5
26 5/4/2020 • 5 2.5
27 6/2/2020 < 5 2.5
28 7/7/2020 6 6
29 8/3/2020 < 5 2.5
30 9/1/2020 < 5 2.5
31 10/6/2020 < 5 2.5
32 11/3/2020 < 2.5
33 12/1/2020 < 2.5
34 1/5/2021 < 5 2.5
35 2/2/2021 < 5 2.5
36 3/2/2021 < 5 2.5
37 4/6/2021 < 5 2.5
38 5/4/2021 < 5 2.5
39 6/1/2021 < 5 2.5
40 7/6/2021 < 5 2.5
41 8/3/2021 < 5 2.5
42 9/7/2021 < 5 2.5
43 10/12/2021 < 5 2.5
44 11/8/2021 < 5 2.5
45 12/7/2021 < 5 2.5
46 1/4/2022 6 6
47 2/1/2022 < 5 2.5
48 3/1/2022 < 5 2.5
49
50
51
52
53
54
55
56
57
58
Use"PASTE SPECIAL
Values"then "COPY".
Maximum data points
= 50
Pall
Copper
0.7068
2.6458
0.2671
48
1.03
6.0 pg/L
6.2 pg/L
Date Data BDL=1/2DL Results
1 4/3/2018 2 2 Std Dev.
2 5/1/2018 < 2 1 Mean
3 6/5/2018 < 2 1 C.V.
4 7/2/2018 < 2 1 n
5 8/7/2018 3 3
6 9/4/2018 3 3 Mull Factor =
7 10/1/2018 4 4 Max. Value
8 11/6/2018 < 2 1 Max. Pred Cw
9 12/4/2018 3 3
10 1/4/2019 5 5
11 2/5/2019 3 3
12 3/5/2019 2 2
13 4/2/2019 3 3
14 5/6/2019 < 2 1
15 6/3/2019 2 2
16 7/1/2019 < 2
17 8/6/2019 3 3
18 9/10/2019 3 3
19 10/1/2019 3 3
20 11/5/2019 2 2
21 12/3/2019 2 2
22 1/6/2020 < 2 1
23 2/3/2020 < 2 1
24 3/3/2020 6 6
25 4/6/2020 3 3
26 5/4/2020 < 2 1
27 6/2/2020 2 2
28 7/7/2020 3 3
29 8/3/2020 4 4
30 9/1/2020 3 3
31 10/6/2020 4 4
32 11/3/2020 2 2
33 12/1/2020 3 3
34 1/5/2021 3 3
35 2/2/2021 2 2
36 3/2/2021 < 3 1.5
37 4/6/2021 2 2
38 5/4/2021 3 3
39 6/1/2021 3 3
40 7/6/2021 3 3
41 8/3/2021 4 4
42 9/7/2021 3 3
43 10/12/2021 3 3
44 11/8/2021 3 3
45 12/7/2021 2 2
46 1/4/2022 58 58
47 2/1/2022 3 3
48 3/1/2022 3 3
49
50
51
52
53
54
55
56
57
58
Use "PASTE SPECIAL
Values" then "COPY".
Maximum data points
= 58
8.0760
3.7188
2.1717
48
1.13
58.00 ug/L
65.54 ug/L
24147 Freshwater RPA, data
9/23/2022

REASONABLE POTENTIAL ANALYSIS
Par12
Cyanide
Date Data BDL=1/2DL Results
1 4/3/2018 < 5 5 Std Dev.
2 5/1/2018 < 5 5 Mean
3 6/5/2018 < 5 5 C.V.
4 7/2/2018 < 5 5 n
5 8/7/2018 < 5 5
6 9/4/2018 < 5 5 MuIt Factor =
7 10/1/2018 < 5 5 Max. Value
8 11/6/2018 < 5 5 Max. Pred Cw
9 12/4/2018 < 5 5
10 1/4/2019 < 5 5
11 2/5/2019 < 5 5
12 3/5/2019 < 5 5
13 4/2/2019 < 5 5
14 5/6/2019 < 5 5
15 6/3/2019 < 5 5
16 7/1/2019 < 5 5
17 8/6/2019 < 5 5
18 9/10/2019 < 5 5
19 10/1/2019 < 5 5
20 11/5/2019 < 5 5
21 12/3/2019 < 5 5
22 1/6/2020 < 5 5
23 2/3/2020 < 5 5
24 3/3/2020 < 5 5
25 4/6/2020 < 5 5
26 5/4/2020 < 5 5
27 6/2/2020 < 5 5
28 7/7/2020 < 5 5
29 8/3/2020 < 5 5
30 9/1/2020 < 5 5
31 10/6/2020 < 5 5
32 11/3/2020 < 5
33 12/1/2020 < 5
34 1/5/2021 < 5 5
35 2/2/2021 < 5 5
36 3/2/2021 < 5 5
37 4/6/2021 < 5 5
38 5/4/2021 < 5 5
39 6/1/2021 < 5 5
40 7/6/2021 < 5 5
41 8/3/2021 < 5 5
42 9/7/2021 < 5 5
43 10/12/2021 < 5 5
44 11/8/2021 < 5 5
45 12/7/2021 < 5 5
46 1/4/2022 < 5 5
47 2/1/2022 < 5 5
48 3/1/2022 < 5 5
49
50
51
52
53
54
55
56
57
58
Use"PASTE SPECIAL
Values"then "COPY".
Maximum data points
= 50
Par13
Fluoride
0.0000
5.00
0.0000
48
1.00
5.0 ug/L
5.0 ug/L
Date Data BDL=1/2DL Results
1 4/3/2018 450 450 Std Dev.
2 5/1/2018 420 420 Mean
3 6/5/2018 130 130 C.V.
4 7/2/2018 480 480 n
5 8/7/2018 330 330
6 9/4/2018 550 550 Mull Factor =
7 10/1/2018 220 220 Max. Value
8 11/6/2018 430 430 Max. Pred Cw
9 12/4/2018 380 380
10 1/4/2019 100 100
11 2/5/2019 270 270
12 3/5/2019 310 310
13 4/2/2019 510 510
14 5/6/2019 460 460
15 6/3/2019 710 710
16 7/1/2019 570 570
17 8/6/2019 610 610
18 9/10/2019 580 580
19 10/1/2019 620 620
20 11/5/2019 590 590
21 12/3/2019 460 460
22 1/6/2020 420 420
23 2/3/2020 460 460
24 3/3/2020 380 380
25 4/6/2020 590 590
26 5/4/2020 480 480
27 6/2/2020 120 120
28 7/7/2020 470 470
29 8/3/2020 540 540
30 9/1/2020 590 590
31 10/6/2020 510 510
32 11/3/2020 530 530
33 12/1/2020 390 390
34 1/5/2021 250 250
35 2/2/2021 240 240
36 3/2/2021 230 230
37 4/6/2021 110 110
38 5/4/2021 < 100 50
39 6/1/2021 470 470
40 7/6/2021 390 390
41 8/3/2021 600 600
42 9/7/2021 620 620
43 10/12/2021 460 460
44 11/8/2021 540 540
45 12/7/2021 160 160
46 1/4/2022 310 310
47 2/1/2022 390 390
48 3/1/2022 460 460
49
50
51
52
53
54
55
56
57
58
Use 'PASTE SPECIAL
Values" then "COPY".
Maximum data points
= 58
162.2181
415.4167
0.3905
48
1.04
710.0 ug/L
738.4 ug/L
24147 Freshwater RPA, data
9/23/2022

REASONABLE POTENTIAL ANALYSIS
Par14
Lead
1
3
4
5
6
7
8
9
10
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
Date BDL=1/2DL
4/3/2018 < 2
5/1/2018 < 2
6/5/2018 < 2
7/2/2018 < 2
8/7/2018 < 2
9/4/2018 < 2
10/1/2018 < 2
11/6/2018 < 2
12/4/2018 < 2
1/4/2019 < 2
2/5/2019 < 2
3/5/2019 < 2
4/2/2019 < 2
5/6/2019 < 2
6/3/2019 < 2
7/1/2019 < 2
8/6/2019 < 2
9/10/2019 < 2
10/1/2019 < 2
11/5/2019 < 2
12/3/2019 < 2
1/6/2020 < 2
2/3/2020 < 2
3/3/2020 < 2
4/6/2020 < 2
5/4/2020 < 2
6/2/2020 < 2
7/7/2020 < 2
8/3/2020 < 2
9/1/2020 < 2
10/6/2020 < 2
11/3/2020 < 2
12/1/2020 < 2
1/5/2021 < 2
2/2/2021 < 2
3/2/2021 < 2
4/6/2021 < 2
5/4/2021 < 2
6/1/2021 < 2
7/6/2021 < 2
8/3/2021 < 2
9/7/2021 < 2
10/12/2021 < 2
11/8/2021 < 2
12/7/2021 < 2
1/4/2022 < 2
2/1/2022 < 2
3/1/2022 < 2
Results
Std Dev.
Mean
C.V.
Mult Factor =
Max. Value
Max. Pred Cw
Use"PASTE SPECIAL
Values"then "COPY".
Maximum data points
= 50
Par15
Mercury
0.0000
1.0000
0.0000
48
1.00
1.000 ug/L
1.000 ug/L
Use 'PASTE SPECIAL
Values" then "COPY".
Maximum data points
= 58
Date Data BDL=1/2DL Results
1 Std Dev. NO DATA
4
5
6
7
Mull Factor =
8Max. Pred Cw N/A
9
2Mean NO DATA
Max. Value
3 C.V. NO DATA
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
24147 Freshwater RPA, data
9/23/2022

REASONABLE POTENTIAL ANALYSIS
Par16
Molybdenum
Date Data BDL=1/2DL Results
1 4/3/2018 9 9 Std Dev.
2 5/1/2018 11 11 Mean
3 6/5/2018 7 7 C.V.
4 7/2/2018 10 10 n
5 8/7/2018 12 12
6 9/4/2018 10 10 MuIt Factor =
7 10/1/2018 7 7 Max. Value
8 11/6/2018 7 7 Max. Pred Cw
9 12/4/2018 14 14
10 1/4/2019 < 5 2.5
11 2/5/2019 6 6
12 3/5/2019 < 5 2.5
13 4/2/2019 7 7
14 5/6/2019 12 12
15 6/3/2019 8 8
16 7/1/2019 9 9
17 8/6/2019 12 12
18 9/10/2019 9 9
19 10/1/2019 10 10
20 11/5/2019 8 8
21 12/3/2019 10 10
22 1/6/2020 6 6
23 2/3/2020 < 5 2.5
24 3/3/2020 < 5 2.5
25 4/6/2020 6 6
26 5/4/2020 9 9
27 6/2/2020 5 5
28 7/7/2020 9 9
29 8/3/2020 9 9
30 9/1/2020 10 10
31 10/6/2020 8 8
32 11/3/2020 8 8
33 12/1/2020 6 6
34 1/5/2021 7 7
35 2/2/2021 10 10
36 3/2/2021 5 5
37 4/6/2021 6 6
38 5/4/2021 7 7
39 6/1/2021 7 7
40 7/6/2021 7 7
41 8/3/2021 9 9
42 9/7/2021 10 10
43 10/12/2021 10 10
44 11/8/2021 13 13
45 12/7/2021 14 14
46 1/4/2022 13 13
47 2/1/2022 6 6
48 3/1/2022 6 6
49
50
51
52
53
54
55
56
57
58
Use"PASTE SPECIAL
Values"then "COPY".
Maximum data Pants
= 50
Par17 & Par18
Nickel
2.8840
8.2083
0.3513
48
1.03
14.0 ug/L
14.4 ug/L
Date Data BDL=1/2D
4/3/2018
5/1/2018
6/5/2018
7/2/2018
8/7/2018
9/4/2018
10/1/2018
11/6/2018
12/4/2018
1/4/2019 <
2/5/2019
3/5/2019
4/2/2019 1
5/6/2019 1
6/3/2019
7/1/2019
8/6/2019
9/10/2019
10/1/2019
11/5/2019
12/3/2019
1/6/2020
2/3/2020
3/3/2020
4/6/2020
5/4/2020
6/2/2020
7/7/2020
8/3/2020
9/1/2020
10/6/2020
11/3/2020
12/1/2020
1/5/2021
2/2/2021
3/2/2021
4/6/2021
5/4/2021
6/1/2021
7/6/2021
8/3/2021 1
9/7/2021
10/12/2021
11/8/2021 1
12/7/2021 1
1/4/2022 1
2/1/2022
3/1/2022
2
Results
Std Dev.
Mean
C.V.
Mull Factor =
Max. Value
Max. Pred Cw
Use"PASTE SPECIAL
Values"then "COPY".
Maximum data Pants
= 50
2.4834
7.6354
0.3253
48
1.03
14.0 pg/L
14.4 pg/L
-10-
24147 Freshwater RPA, data
9/23/2022

REASONABLE POTENTIAL ANALYSIS
Par19
Selenium
Date Data BDL=1/2DL Results
1 4/3/2018 < 3 1.5 Std Dev.
2 5/1/2018 < 3 1.5 Mean
3 6/5/2018 < 3 1.5 C.V.
4 7/2/2018 < 3 1.5 n
5 8/7/2018 < 3 1.5
6 9/4/2018 < 3 1.5 MuIt Factor=
7 10/1/2018 < 3 1.5 Max. Value
8 11/6/2018 < 3 1.5 Max. Pred Cw
9 12/4/2018 < 3 1.5
10 1/4/2019 < 3 1.5
2/5/2019 < 3 1.5
12 3/5/2019 < 3 1.5
13 4/2/2019 < 3 1.5
14 5/6/2019 < 3 1.5
15 6/3/2019 < 3 1.5
16 7/1/2019 < 3 1.5
17 8/6/2019 < 3 1.5
18 9/10/2019 < 3 1.5
19 10/1/2019 < 3 1.5
20 11/5/2019 < 3 1.5
21 12/3/2019 < 3 1.5
22 1/6/2020 < 3 1.5
23 2/3/2020 < 3 1.5
24 3/3/2020 < 3 1.5
25 4/6/2020 < 3 1.5
26 5/4/2020 < 3 1.5
27 6/2/2020 < 3 1.5
28 7/7/2020 < 3 1.5
29 8/3/2020 < 3 1.5
30 9/1/2020 < 3 1.5
31 10/6/2020 < 3 1.5
32 11/3/2020 < 3 1.5
33 12/1/2020 < 3 1.5
34 1/5/2021 < 3 1.5
35 2/2/2021 < 3 1.5
36 3/2/2021 < 3 1.5
37 4/6/2021 < 1.5
38 5/4/2021 < 1.5
39 6/1/2021 < 1.5
40 7/6/2021 < 3 1.5
41 8/3/2021 < 3 1.5
42 9/7/2021 < 3 1.5
43 10/12/2021 < 3 1.5
44 11 /8/2021 < 3 1.5
45 12/7/2021 < 3 1.5
46 1/4/2022 < 3 1.5
47 2/1/2022 < 3 1.5
48 3/1/2022 < 3 1.5
49
50
51
52
53
54
55
56
57
58
1
Use"PASTE SPECIAL
Values"then "COPY".
Maximum data points
= 50
Par20
Silver
0.0000
1.5000
0.0000
48
1.00
1.5 ug/L
1.5 ug/L
Date Data BDL=1/2DL Results
1 4/3/2018 < 0.5 Std Dev.
2 5/1/2018 < 0.5 Mean
3 6/5/2018 < 0.5 C.V.
4 7/2/2018 < 0.5 n
5 8/7/2018 < 0.5
6 9/4/2018 < 1 0.5 Mull Factor =
7 10/1/2018 < 1 0.5 Max. Value
8 11/6/2018 < 0.5 Max. Pred Cw
9 12/4/2018 < 0.5
10 1/4/2019 < 0.5
11 2/5/2019 < 0.5
12 3/5/2019 < 0.5
13 4/2/2019 < 1 0.5
14 5/6/2019 < 1 0.5
15 6/3/2019 < 1 0.5
16 7/1/2019 < 1 0.5
17 8/6/2019 < 1 0.5
18 9/10/2019 < 1 0.5
19 10/1/2019 < 1 0.5
20 11/5/2019 < 1 0.5
21 12/3/2019 < 1 0.5
22 1/6/2020 < 1 0.5
23 2/3/2020 < 1 0.5
24 3/3/2020 < 1 0.5
25 4/6/2020 < 1 0.5
26 5/4/2020 < 1 0.5
27 6/2/2020 < 1 0.5
28 7/7/2020 < =I 0.5
29 8/3/2020 < 1 0.5
30 9/1/2020 < 1 0.5
31 10/6/2020 < 1 0.5
32 11/3/2020 < 1 0.5
33 12/1/2020 < 1 0.5
34 1/5/2021 < 1 0.5
35 2/2/2021 < 1 0.5
36 3/2/2021 < 1 0.5
37 4/6/2021 < 1 0.5
38 5/4/2021 < 1 0.5
39 6/1/2021 < 1 0.5
40 7/6/2021 < 1 0.5
41 8/3/2021 < 1 0.5
42 9/7/2021 < 1 0.5
43 10/12/2021 < 1 0.5
44 11/8/2021 < 1 0.5
45 12/7/2021 < 1 0.5
46 1/4/2022 < 1 0.5
47 2/1/2022 < 1 0.5
48 3/1/2022 < 1 0.5
49
50
51
52
53
54
55
56
57
58
Use 'PASTE SPECIAL
Values" then "COPY".
Maximum data points
= 58
0.0000
0.5000
0.0000
48
1.00
0.500 ug/L
0.500 ug/L
24147 Freshwater RPA, data
9/23/2022

REASONABLE POTENTIAL ANALYSIS
Par21
Zinc
Use"PASTE SPECIAL
Values. then "COPY".
Maximum data points
= 50
Date Data BDL=1/2DL Results
1 4/3/2018 40 40 Std Dev. 20.3776
2 5/1/2018 44 44 Mean 45.1667
3 6/5/2018 56 56 C.V. 0.4512
4 7/2/2018 71 71 n 48
5 8/7/2018 46 46
6 9/4/2018 62 62 Mult Factor= 1.04
7 10/1/2018 36 36 Max. Value 152.0 ug/L
8 11/6/2018 29 29 Max. Pred Cw 158.1 ug/L
9 12/4/2018 43 43
10 1/4/2019 32 32
11 2/5/2019 54 54
12 3/5/2019 27 27
13 4/2/2019 51 51
14 5/6/2019 44 44
15 6/3/2019 37 37
16 7/1/2019 36 36
17 8/6/2019 72 72
18 9/10/2019 43 43
19 10/1/2019 37 37
20 11/5/2019 43 43
21 12/3/2019 32 32
22 1/6/2020 26 26
23 2/3/2020 36 36
24 3/3/2020 70 70
25 4/6/2020 68 68
26 5/4/2020 51 51
27 6/2/2020 43 43
28 7/7/2020 46 46
29 8/3/2020 60 60
30 9/1/2020 37 37
31 10/6/2020 43 43
32 11/3/2020 37 37
33 12/1/2020 23 23
34 1/5/2021 17 17
35 2/2/2021 16 16
36 3/2/2021 32 32
37 4/6/2021 42 42
38 5/4/2021 43 43
39 6/1/2021 47 47
40 7/6/2021 31 31
41 8/3/2021 45 45
42 9/7/2021 50 50
43 10/12/2021 28 28
44 11/8/2021 52 52
45 12/7/2021 51 51
46 1/4/2022 152 152
47 2/1/2022 43 43
48 3/1/2022 44 44
49
50
51
52
53
54
55
56
57
58
Par22
0
Use "PASTE SPECIAL.
Values. then "COPY".
Maximum data points
= 50
Date Data BDL=1/2DL Results
1 Std Dev. NO DATA
4
5
6
7
8Max. Pred Cw N/A
9
2Mean NO DATA
Max. Value
3 C.V. NO DATA
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
- 12 -
24147 Freshwater RPA, data
9/23/2022

Big Buffalo WWTP
NC0024147
Freshwater RPA - 95% Probability/95% Confidence Using Metal Translators
MAXIMUM DATA POINTS = 58
Qw (MGD) = 12.0000
1Q10S (cfs) = 18.56
7Q1OS (cfs) = 22.50
7Q1OW (cfs) = 33.60
30Q2 (cfs) = NO 30Q2 DATA
Avg. Stream Flow, QA (cfs) = 1260.00
Receiving Stream: Deep River HUC 03030003
WWTP/WTP Class: Grade IV
IWC% @ 1Q10S = 50.05382131
IWC% @ 7Q10S = 45.25547445
IWC% @ 7Q1OW = 35.63218391
IWC% @ 30Q2 = N/A
IW%C @ QA = 1.454716096
Stream Class: C
Outfall 001
Qw = 12 MGD
COMBINED HARDNESS (mg/L)
Acute = 48.75 mg/L
Chronic = 47.16 mg/L
PARAMETER
TYPE
NC STANDARDS OR EPA CRITERIA
Jto
a
REASONABLE POTENTIAL RESULTS
RECOMMENDED ACTION
Chronic Applied Acute
Standard
11 # Det. Max Pred Cw Allowable Cw
Arsenic
Arsenic
C
C
150 FW(7Q10s) 340
10 HH/WS(Qavg)
ug L
ug/L
48 0
1.5
NO DETECTS
Acute (FW): 679.3
_ _ _ _ _ _ _
Chronic (FW): 331.5
Max MDL=3 _ _ _ _
Chronic (HH): 687.4
Max MDL = 3
_ _ _ _ _
No detects
_ _ _ _ _
Beryllium
NC
6.5 FW(7Q10s) 65
ug L
4 0
Note: n < 9
Limited data set
6.48
C.V. (default)
NO DETECTS
Acute: 129.86
___ _ _______ _____
Chronic: 14.36
Max MDL = 5
_ _ _____________________
No detects
Cadmium
NC
0.9531 FW(7Q10s) 5.8029
ug L
48 0
I 0.250
NO DETECTS
Acute: 11.593
— — — — — — — — —
Chronic: 2.106
Max MDL = 0.5
— — — — — — — — — — — — — —
No detects
Chlorides
NC
230 FW(7Q10s)
mg;L
48 48
111.2
Acute: NO WQS
___ _ _______ _____
Chronic: 508.2
No value > Allowable Cw
_ _ _ _ _ _ _ _ _ _ _ _ _
No RP, Predicted Max < 50% of Allowable Cw - No
Monitoring required
Chlorinated Phenolic Compounds
NC
1 A(30Q2)
ug/L
0 0
N/A
Acute: NO WQS
-- Chronic:-----IWC?------------------------------
Total Phenolic Compounds
NC
300 A(30Q2)
ug/L
4 2
Note: n < 9
Limited data set
82.9
C.V. (default)
Acute: NO WQS
___ _ _______ _______________________________
Chronic: IWC?
Chromium III
NC
197.9962 FW(7Q10s) 1564.0418
µg/L
0 0
N/A
Acute: 3,124.7
-- Chronic:-----437.5------------------------------
Chromium VI
NC
11 FW(7Q10s) 16
pg L
0 0
N/A
Acute: 32.0
------------------------------
Chromium, Total
NC
µg/L
Tot Cr value(s)
48 2
> 5 but < Cr VI
6.2
I
Allowable Cw
Max reported value = 6
a: No monitoring required if all Total Chromium
samples are < 5 pg/L or Pred. max for Total Cr is <
allowable Cw for Cr VI.
Page 13 of 14
24147 Freshwater RPA, rpa
9/23/2022

Big Buffalo WWTP
NC0024147
Freshwater RPA - 95% Probability/95% Confidence Using Metal Translators
Outfall 001
Qw = 12 MGD
Copper
NC
13.5553
FW(7Q10s)
19.6483
ug/L
48
38
65.54
Acute: 39.25
___ _ _______ _____
Chronic: 29.95
1 value(s) > Allowable Cw
_ _ _ _ _ _ _ _ _ _ _____
RP based on one high value - apply monthly
monitoring
Cyanide
NC
5
FW(7Q10s)
22
10
ug/L
48
0
5.0
NO DETECTS
Acute: 44.0
___ _ _______ _____
Chronic: 11.0
Max MDL = 10
_ _ _____________________
No detects
Fluoride
NC
1800
FW(7Q10s)
ug/L
48
47
738.4
Acute: NO WQS
___ _ _____ _ _ ___
Chronic: 3,977.4
No value > Allowable Cw
_ _ _ _ _ _ _ _ _ _ _ _ _
No RP, Predicted Max < 50% of Allowable Cw - No
Monitoring required
Lead
NC
5.9846
FW(7Q10s)
159.3401
ug/L
48
0
1.000
NO DETECTS
Acute: 318.338
___ _ _______ _ ___
Chronic: 13.224
Max MDL = 2
_ _ _____________________
No detects
Mercury
NC
12
FW(7Q10s)
0.5
ng/L
0
0
N/A
Acute: NO WQS
------------------------
Molybdenum
NC
2000
HH(7Q 10s)
ug/L
48
44
14.4
Acute: NO WQS
_ _ _ _ _ _ _ _ _ _ _ _ _
Chronic: 4,419.4
No value > Allowable Cw
_ _ _ _ _ _ _ _ _ _ _ _ _ _
No RP, Predicted Max < 50% of Allowable Cw - No
Monitoring required
Nickel
Nickel
NC
NC
63.6959
25.0000
FW(7Q10s)
WS(7Q10s)
589.8037
µg/L
µg/L
48
47
14.4
Acute (FW): 1,178.3
_ _ _ _ _ _ _ _ _ _ _ _
Chronic (FW): 140.7
No value > Allowable Cw
Chronic (WS): 55.2
No value > Allowable Cw
_ _ _ _ _ _ _ _ _ _ _ _ _ _
No RP, Predicted Max < 50% of Allowable Cw - No
Monitoring required
Selenium
NC
5
FW(7Q10s)
56
ug/L
48
0
1.5
NO DETECTS
Acute: 111.9
___ _ _______ _____
Chronic: 11.0
Max MDL = 3
_ _ _____________________
No detects
Silver
NC
0.06
FW(7Q10s)
0.9349
ug/L
48
0
0.500
NO DETECTS
Acute: 1.868
___ _ _______ _____
Chronic: 0.133
Max MDL = 1
_ _ _____________________
No detects
Zinc
NC
216.9965
FW(7Q10s)
221.3719
ug/L
48
48
158.1
Acute: 442.3
___ _ _______ _____
Chronic: 479.5
No value > Allowable Cw
_ _ _ _ _ _ _ _ _ _ _ _ _
No RP, Predicted Max < 50% of Allowable Cw - No
Monitoring required
0
0
N/A
Acute:
_ _ _
Chronic:
0
0
N/A
Acute:
-- _ _ _
------------ Chronic:
Page 14 of 14
24147 Freshwater RPA, rpa
9/23/2022

Sanford - Big Buffalo WWTP / NC0024147
Mercury Data Statistics (Method 1631E)
2018
2019
2020
2021
2022
# of Samples
4
4
4
5
1
Annual Average, ng/L
1.0
1.6
0.5
0.5
0.5
Maximum Value, ng/L
2.62
4.70
0.50
0.50
0.50
TBEL, ng/L
47
WQBEL, ng/L
26.5

9/23/22 WQS = 12 ng/L MERCURY WQBEL/TBEL EVALUATION V:2013-6
Facility Name
Sanford - Big Buffalo WWTP / NC0024147
/Permit No. :
Total Mercury 1631E PQL = 0.5 ng/L 7Q10s =
Date Modifier Data Entry Value Permitted Flow =
6/5/18 < 1
6/13/18 2.62
9/24/18 < 1
12/3/18 < 1
3/12/19 < 1
6/10/19 4.7
9/9/19 < 1
12/10/19 < 1
3/9/20 < 1
6/1/20 < 1
9/14/20 < 1
12/8/20 < 1
3/23/21 < 1
6/15/21 < 1
9/14/21 < 1
9/21/21 < 1
12/14/21 < 1
3/8/22 < 1
No Limit Required
MMP Required
0.5
2.62
0.5
0.5
0.5
4.7
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
22.500
12.000
cfs
WQBEL =
26.52 ng/L
47 ng/L
1.0 ng/L - Annual Average for 2018
1.6 ng/L - Annual Average for 2019
0.5 ng/L - Annual Average for 2020
0.5 ng/L - Annual Average for 2021
0.5 ng/L - Annual Average for 2022

2011 Cape Fear River Basin Plan & NPDES Permitting Strategy
DRAFT
Elements of Basin Plan
NPDES Permitting Strategy
Subwatershed
Subwatershed
Location
Status on
303(d) List
Applicable Nutrient
Strategy
Existing WWTPs
New or Expanding WWTPs
Jordan Lake
Jordan Dam
to headwaters
Impaired for
chl-a, pH,
turbidity
Jordan Lake TMDLs and
Nutrient Strategy Rules
Continue to implement Jordan Lake WS Nutrient Strategy Rules
Expanded Upper
Middle Cape Fear
Buckhorn Dam to
Randleman and
Jordan Lake Dams
Currently
impaired for
chl-a
(@ NCSR 42)
Nutrient TMDL
to be developed
Implement TMDL/ NMS, once established
In interim, perform add'I effluent
nutrient monitoring (permit
reopener), take part in modeling &
TMDL efforts.
In interim, no net increase in
N&P loads in the subwatershed
Lower Middle
Cape Fear
Buckhorn Dam to
Lock & Dam #1
Supporting
(with
(with surficial
algal blooms)
Monitoring & modeling,
followed by D.O. &/or
nutrient strategies/ TMDLs
(W. Wake study)
Implement TMDL(s)/ strategies, once established
In interim, perform add'I effluent
nutrient monitoring (permit
take in &
reopener);partmodeling
TMDL efforts.
In interim, calibrated nutrient
response model is prerequisite
p p q
to permit approval
Lower
Cape Fear
Below Lock & Dam #1
Impaired for
D.O.
TMDL on hold, pending
decision/ action on site-
specific D.O. standards
Implement TMDL/ SSS, once established
In interim, no net increase in
permitted loads of 02-demanding
In interim, no net increase in
actual loads of 02-demanding
wastes in the subwatershed
wastes in the subwatershed
• Include this language in NPDES permits for nutrient -bearing dischargers with maximum permitted flows >0.1 MGD in the Expanded Upper Middle Cape Fear
and Lower Middle Cape Fear permits:
"Pursuant to N.C. General Statute Section 143-215.1; the implementing rules found in Title 15A of the North Carolina Administrative Code, Subchapters 2B and
2H, specifically, 15A NCAC 02B .0505 and 02H.0112(b)(1); and Part II, Section B, Condition 13 of this permit; the Director may reopen this permit to require
supplemental monitoring of the Permittee's effluent discharge. The additional monitoring is necessary to support water quality modeling efforts within the
Cape Fear River Basin and shall be consistent with a monitoring plan developed jointly by the Division and affected stakeholders."
• Standardize monitoring requirements by segment for facility types/permitted flow categories.
CFR 2011 NPDES Permitting Strategy_Sep 2011 -final draft for basin plan
9/15/2015

Reduction in Frequency Evalaution
Facility:
Big Buffalo WWTP
Permit No.
NC0024147
Review period (use 3
yrs)
04/2019 03/2022
Approval Criteria:
Y/N?
1. Not currently under SOC
Y
2. Not on EPA Quarterly noncompliance report
Y
3. Facility or employees convicted of CWA
violations
N
Data Review
Units
Weekly
average limit
Monthly
average
limit
50%
MA
3-yr mean
(geo mean
for FC)
< 50%?
200%
MA
# daily
samples
> 200%
< 15?
200% # daily
samples
WA > 200%
< 20?
# of non -
monthly
limit
violations
> 2?
# civil penalty
asessment
> 1?
Reduce
Frequency?
(Yes/No)
CBOD (weighted)
mg/L
10.29
6.75
3.4
2.20
Y
13.5
3
Y
0
N
0
N
Y
TSS
mg/L
45
30
15
1.06
Y
60
3
Y
0
N
0
N
Y
Ammonia (weighted)
mg/L
3.17
1.04
0.5
0.49
Y
2.08
2
Y
0
N
0
N
Y
Fecal Coliform
#/100
400
200
100
10.67
Y
800 1
Y
0
N
0
N
Y