NC0020761_Fact Sheet_20210512

Fact Sheet
NPDES Permit No. NCOO2O761
Permit Writer/Email Contact Nick Coco, [e-mail]:
Date: February 26, 2021
Division/Branch: NC Division of Water Resources/NPDES Municipal Permitting
Fact Sheet Template: Version 09Jan2017
Permitting Action:
❑X Renewal
❑ Renewal with Expansion
❑ New Discharge
❑ Modification (Fact Sheet should be tailored to mod request)
Note: A complete application should include the following:
• For New Dischargers, EPA Form 2A or 2D requirements, Engineering Alternatives Analysis, Fee
• For Existing Dischargers (POTW), EPA Form 2A, 3 effluent pollutant scans, 4 2"d species WET
tests.
• For Existing Dischargers (Non-POTW), EPA Form 2C with correct analytical requirements based
on industry category.
Complete applicable sections below. If not applicable, enter NA.
1. Basic Facility Information
Facility Information
Applicant/Facility Name:
Town of North Wilkesboro/ Thurman Street Wastewater Treatment
Plant (WWTP)
Applicant Address:
P.O. Box 218, North Wilkesboro, NC 28659
Facility Address:
100 Thurman Street, North Wilkesboro, NC 28659
Permitted Flow:
2.0 MGD
Facility Type/Waste:
MAJOR Municipal; 95.8% domestic, 4.2% industrial*
Facility Class:
Grade III Biological Water Pollution Control System
Treatment Units:
Mechanical bar screen with manual bypass bar screen, Grit chamber,
Influent composite sampler, Influent pump station with four (4) influent
pumps, Influent flow meter, Three (3) 0.064 MG primary clarifiers
with sludge pump station, Two (2) 0.5 MG aeration basins with
mechanical aerators, Splitter box, Four (4) 0.099 MG secondary
clarification with RAS and WAS pumps, Effluent flow meter,
UV disinfection system, Effluent composite sampler, Two (2) 0.279
MG aerobic digestors with blowers, One (1) 0.03 MG sludge thickener
tank with pumps and blower, One (1) 0.99 MG sludge holding/decant
tank with mixer, and truck load out station and pump, Six (6) 2,500
ft2 drying beds with drain system to headworks (receiving for pump
and haul materials), Backup generator
Pretreatment Program (Y/N)
Y
County:
Wilkes
Region
Winston-Salem
*Based on permitted flows
Briefly describe the proposed permitting action and facility background: The Town of North
Wilkesboro has applied for an NPDES permit renewal at 2.0 MGD for the Thurman Street WWTP. This
Page 1 of 9

facility serves a population of approximately 5,700 residents. The facility also serves 2 categorical
significant industrial users (CIUs) via a pretreatment program. Treated wastewater is discharged into the
Yadkin River, a class C water in the Yadkin -Pee Dee River Basin. The facility has a primary Outfall 001.
Note: In their renewal application, the Town referred to their WWTP as the North Wilkesboro WWTP.
Upon discussion with the Town, they have requested that this be considered a typo and that Thurman
Street WWTP remain the name of their facility.
2. Receiving Waterbodv Information:
Receiving Waterbody Information
Outfalls/Receiving Stream(s):
Outfall 001 — Yadkin River
Stream Index:
12-(38)
Stream Classification:
C
Drainage Area (mi2):
526
Summer 7Q10 (cfs)
196
Winter 7Q10 (cfs):
267
30Q2 (cfs):
393
Average Flow (cfs):
683
IWC (% effluent):
1.6
2018 303(d) listed/parameter:
No
Subject to TMDL/parameter:
Yes- State wide Mercury TMDL implementation.
Subbasin/HUC:
03-07-01/03040101
USGS Topo Quad:
C14NW Wilkesboro, NC
3. Effluent Data Summary
Effluent data for Outfall 001 is summarized below for the period of July 2016 through July 2020.
Table 1. Effluent Data Summary Outfall 001
Parameter
Units
Average
Max
Min
Permit
Limit
Flow
MGD
1.2
4.488
0.671
MA 2.0
BOD
mg/1
4.0
11.3
2
WA 45
MA 30
TSS
mg/1
6.6
51
2.5
WA 45.0
MA 30.0
NH3N summer
mg/1
0.5
3.2
0.02
WA 27.0
MA 9.0
Page 2 of 9

NH3N winter
mg/1
0.3
2
Q
WA 35.0
MA 24.0
Fecal coliform
#/100 ml
3
246
(geometric)
WA 400
MA 200
Temperature
° C
17.2
24
,._,
pH
SU
6.6
7.45
6
6.0 < PH <
9.0
Total Silver
ug/1
< 5
< 5
< 5
TN
mg/1
6.7
23.5
1.6
TP
mg/1
0.5
1.56
0.02
MA -Monthly Average, WA -Weekly Average, DM -Daily Maximum, DA-Daily
Average, QA-Quarterly Average
4. Instream Data Summary
Instream monitoring may be required in certain situations, for example: 1) to verify model predictions
when model results for instream DO are within 1 mg/1 of instream standard at full permitted flow; 2) to
verify model predictions for outfall diffuser; 3) to provide data for future TMDL; 4) based on other
instream concerns. Instream monitoring may be conducted by the Permittee, and there are also
Monitoring Coalitions established in several basins that conduct instream sampling for the Permittee (in
which case instream monitoring is waived in the permit as long as coalition membership is maintained).
If applicable, summarize any instream data and what instream monitoring will be proposed for this
permit action: The current permit requires instream monitoring for fecal coliform upstream of the outfall
at least 100 yards and downstream of the outfall at least 100 yards. The Town is a member of the Yadkin -
Pee Dee River Basin Association (YPDRBA) and their instream requirements are provisionally waived as
long as they maintain membership. There are no nearby YPDRBA or Ambient Monitoring (AMS)
stations upstream of the facility. YPDRBA Station Q0450000 is located just downstream of the discharge.
As such, only downstream data (January 2017 — June 2020) has been observed. The data has been
summarized in Table 2 below.
Table 2. Instream Ambient Monitoring Station Data Summary
Parameter
Units
-
Q0450000 Downstream
Geomean
Max
Min
Fecal Coliform
#/100 ml
112
6300
21
Downstream fecal coliform did not exceed a geometric mean of 200/100m1 during the period reviewed,
nor did it exceed 400/100m1 in more than 20% of the samples examined [15A NCAC 02B .0211].
The current permit requires instream fecal coliform monitoring at a 3/week frequency. Per 15A NCAC
02B .0508, water quality limited Grade III facilities should be monitoring for effluent fecal coliform three
times per week during June, July, August, and September, and once per week during the rest of the year.
As such, the monitoring frequency for instream fecal coliform has been modified. This change will only
take effect in the event the facility ceases YPDRBA membership.
Is this facility a member of a Monitoring Coalition with waived instream monitoring (Y/N): Y
Name of Monitoring Coalition: Yadkin -Pee Dee River Basin Association (YPDRBA)
Page 3 of 9

5. Compliance Summary
Summarize the compliance record with permit effluent limits (past 5 years): The facility reported no limit
violations during the period reviewed.
Summarize the compliance record with aquatic toxicity test limits and any second species test results
(past 5 years): The facility passed 16 of 16 quarterly chronic toxicity tests from January 2017 to
December 2020, as well as 4 of 4 second species toxicity tests conducted in 2016, 2017, 2018 and 2019.
Summarize the results from the most recent compliance inspection: The last facility inspection conducted
in January 2020 reported that the facility was in compliance with NPDES permit NC0020761.
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: 1Q10 streamflow (acute Aquatic Life); 7Q10 streamflow (chronic Aquatic
Life; non -carcinogen HH); 30Q2 streamflow (aesthetics); annual average flow (carcinogen, HH).
If applicable, describe any other dilution factors considered (e.g., based on CORMIX model results): NA
If applicable, describe any mixing zones established in accordance with 1SA NCAC 2B.0204(b): NA
Oxygen -Consuming Waste Limitations
Limitations for oxygen -consuming waste (e.g., BOD) are generally based on water quality modeling to
ensure protection of the instream dissolved oxygen (DO) water quality standard. Secondary TBEL limits
(e.g., BOD= 30 mg/1 for Municipals) may be appropriate if deemed more stringent based on dilution and
model results.
If permit limits are more stringent than TBELs, describe how limits were developed: Limitations for
BOD5 are secondary TBEL limits consistent in the permit since 1995's Wasteload Allocation. No
changes are proposed.
Ammonia and Total Residual Chlorine Limitations
Limitations for ammonia are based on protection of aquatic life utilizing an ammonia chronic criterion of
1.0 mg/1 (summer) and 1.8 mg/1 (winter). Acute ammonia limits are derived from chronic criteria,
utilizing a multiplication factor of 3 for Municipals and a multiplication factor of 5 for Non -Municipals.
Limitations for Total Residual Chlorine (TRC) are based on the NC water quality standard for protection
of aquatic life (17 ug/1) and capped at 28 ug/1 (acute impacts). Due to analytical issues, all TRC values
reported below 50 ug/1 are considered compliant with their permit limit.
Describe any proposed changes to ammonia and/or TRC limits for this permit renewal: As the facility
uses UV disinfection with no backup chlorination, the existing permit does not set TRC limits or
monitoring requirements. There are no proposed changes for TRC.
The current ammonia limits are based on a Level B modeling analysis conducted in 1994 in which the
interaction between the Thurman Street WWTP and the Wilkesboro WWTP was taken into account. The
limits have been reviewed in the attached WLA spreadsheet and have been found to be protective. There
are no proposed changes for ammonia limits.
Page 4 of 9

Reasonable Potential Analysis (RPA) for Toxicants
If applicable, conduct RPA analysis and complete information below.
The need for toxicant limits is based upon a demonstration of reasonable potential to exceed water quality
standards, a statistical evaluation that is conducted during every permit renewal utilizing the most recent
effluent data for each outfall. The RPA is conducted in accordance with 40 CFR 122.44 (d) (i). The NC
RPA procedure utilizes the following: 1) 95% Confidence Level/95% Probability; 2) assumption of zero
background; 3) use of detection limit for "less than" values; and 4) streamflows used for dilution
consideration based on 15A NCAC 2B.0206. Effective April 6, 2016, NC began implementation of
dissolved metals criteria in the RPA process in accordance with guidance titled NPDES Implementation of
Instream Dissolved Metals Standards, dated June 10, 2016.
A reasonable potential analysis was conducted on effluent toxicant data collected between April 2017
through January 2021. 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: N/A
• 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: N/A
• 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 Silver
• POTW Effluent Pollutant Scan Review: Three effluent pollutant scans were evaluated for
additional pollutants of concern. (Scans from 2016, 2017, 2018 and 2017-2018 STMP data)
o The following parameter(s) will receive a water quality -based effluent limit (WQBEL)
with monitoring, since as part of a limited data set, two samples exceeded the allowable
discharge concentration: N/A
o The following parameter(s) will receive a monitor -only requirement, since as part of a
limited data set, one sample exceeded the allowable discharge concentration: N/A
o The following parameters will not receive a limit or monitoring, since they did not
demonstrate reasonable potential to exceed applicable water quality standards/criteria and
the maximum predicted concentration was <50% of the allowable concentration: Total
Arsenic, Total Beryllium, Total Cadmium, Total Phenolic Compounds, Total Chromium,
Total Copper, Total Cyanide, Total Lead, Total Molybdenum, Total Nickel, Total
Selenium, Total Zinc
If applicable, attach a spreadsheet of the RPA results as well as a copy of the Dissolved Metals
Implementation Fact Sheet for freshwater/saltwater to this Fact Sheet. Include a printout of the RPA
Dissolved to Total Metal Calculator sheet if this is a Municipality with a Pretreatment Program.
Toxicity Testing Limitations
Permit limits and monitoring requirements for Whole Effluent Toxicity (WET) have been established in
accordance with Division guidance (per WET Memo, 8/2/1999). Per WET guidance, all NPDES permits
issued to Major facilities or any facility discharging "complex" wastewater (contains anything other than
domestic waste) will contain appropriate WET limits and monitoring requirements, with several
exceptions. The State has received prior EPA approval to use an Alternative WET Test Procedure in
Page 5 of 9

NPDES permits, using single concentration screening tests, with multiple dilution follow-up upon a test
failure.
Describe proposed toxicity test requirement: The permit requires quarterly chronic toxicity testing at
1.6% effluent concentration. No changes are proposed.
Mercury Statewide TMDL Evaluation
There is a statewide TMDL for mercury approved by EPA in 2012. The TMDL target was to comply
with EPA's mercury fish tissue criteria (0.3 mg/kg) for human health protection. The TMDL established a
wasteload allocation for point sources of 37 kg/year (81 lb/year), and is applicable to municipals and
industrial facilities with known mercury discharges. Given the small contribution of mercury from point
sources (-2% of total load), the TMDL emphasizes mercury minimization plans (MMPs) for point source
control. Municipal facilities > 2 MGD and discharging quantifiable levels of mercury (>1 ng/1) will
receive an MMP requirement. Industrials are evaluated on a case -by -case basis, depending if mercury is a
pollutant of concern. Effluent limits may also be added if annual average effluent concentrations exceed
the WQBEL value (based on the NC WQS of 12 ng/l) and/or if any individual value exceeds a TBEL
value of 47 ng/1.
Table 3. Mercury Effluent Data Summary (2.0 MGD)
2016
2017
2018
# of Samples
1
1
1
Annual Average Conc. ng/L
< 200
5.25
9.54
Maximum Conc., ng/L
< 200
5.25
9.54
TBEL, ng/L
47
WQBEL, ng/L
770.7
Note: In their 2016 PPA, the facility reported total mercury at non -detect < 200 ng/L. The correct low-
level mercury method was used during the 2017 and 2018 PPA scans.
Describe proposed permit actions based on mercury evaluation: Since no annual average mercury
concentration exceeded the WQBEL, and no individual mercury sample exceeded the TBEL, no mercury
limit is required. Since the facility is not > 2.0 MGD, a mercury minimization plan (MMP) is not
required.
Other TMDL/Nutrient Management Strategy Considerations
If applicable, describe any other TMDLs/Nutrient Management Strategies and their implementation
within this permit: In 2008, the Division's Modeling and TMDL Unit advised the Permittee the Yadkin
Pee -Dee River Basin Association had agreed to conduct additional instream monitoring, April 2008 —
March 2010, in connection with the facility membership. The additional sampling is to be used in
developing a TMDL for High Rock Lake. The permit would not be reopened to reflect this change at this
time but may be subject to reopening in the future when the nutrient management strategy is completed.
The Modeling and TMDL Unit has requested a special reopener condition for all NPDES dischargers
upstream of High Rock Lake be added to assist with sampling in connection with High Rock Lake
nutrient TMDL and/or nutrient strategy development.
Other WQBEL Considerations
If applicable, describe any other parameters of concern evaluated for WQBELs: NA
Page 6 of 9

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
BODS/TSS for Monthly Average, and 45 mg/l for BOD5/TSS for Weekly Average). YES
If NO, provide a justification for alternative limitations (e.g., waste stabilization pond). NA
Are 85% removal requirements for BODS/TSS included in the permit? YES
If NO, provide a justification (e.g., waste stabilization pond). NA
8. Antidegradation Review (New/Expanding Discharge):
The objective of an antidegradation review is to ensure that a new or increased pollutant loading will not
degrade water quality. Permitting actions for new or expanding discharges require an antidegradation
review in accordance with 15A NCAC 2B.0201. Each applicant for a new/expanding NPDES permit
must document an effort to consider non -discharge alternatives per 15A NCAC 2H.0105( c)(2). In all
cases, existing instream water uses and the level of water quality necessary to protect the existing use is
maintained and protected.
If applicable, describe the results of the antidegradation review, including the Engineering Alternatives
Analysis (EAA) and any water quality modeling results: NA
9. Antibacksliding Review:
Sections 402(o)(2) and 303(d)(4) of the CWA and federal regulations at 40 CFR 122.44(1) prohibit
backsliding of effluent limitations in NPDES permits. These provisions require effluent limitations in a
reissued permit to be as stringent as those in the previous permit, with some exceptions where limitations
may be relaxed (e.g., based on new information, increases in production may warrant less stringent TBEL
limits, or WQBELs may be less stringent based on updated RPA or dilution).
Are any effluent limitations less stringent than previous permit (YES/NO): NO
If YES, confirm that antibacksliding provisions are not violated: NA
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
Page 7 of 9

considered effluent limitations under Section 402(o) of the Clean Water Act, and therefore anti -
backsliding prohibitions would not be triggered by reductions in monitoring frequencies.
For instream monitoring, refer to Section 4.
11. Electronic Reporting Requirements
The US EPA NPDES Electronic Reporting Rule was finalized on December 21, 2015. Effective
December 21, 2016, NPDES regulated facilities are required to submit Discharge Monitoring Reports
(DMRs) electronically. While NPDES regulated facilities would initially be required to submit additional
NPDES reports electronically effective December 21, 2020, EPA extended this deadline from December
21, 2020, to December 21, 2025. The current compliance date, effective January 4, 2021, was extended as
a final regulation change published in the November 2, 2020 Federal Register. This permit contains the
requirements for electronic reporting, consistent with Federal requirements.
12.Summary of Proposed Permitting Actions:
Table 4. Current Permit Conditions and Proposed Changes 2.0 MGD
Parameter
Current Permit
Proposed Change
Basis for Condition/Change
Flow
MA 2.0 MGD
No change
15A NCAC 2B .0505
BOD5
MA 30 mg/1
WA 45 mg/1
No change
TBEL. Secondary treatment
standards/40 CFR 133 / 15A
NCAC 2B .0406; 1995 WLA.
NH3-N
Summer:
MA 9.0 mg/1
WA 27.0 mg/1
Winter:
MA 24.0 mg/1
WA 35.0 mg/1
No change
WQBEL. 1995 Level B Model.
2020 WLA review. 15A NCAC
2B.
TSS
MA 30 mg/1
WA 45 mg/1
No change
TBEL. Secondary treatment
standards/40 CFR 133 / 15A
NCAC 2B .0406;
Fecal coliform
MA 200 /100m1
WA 400 /100m1
No change
WQBEL. State WQ standard, 15A
NCAC 2B
Instream Fecal
Coliform
Monitor and Report
3/Week
Monitor and Report three
times per week during June,
July, August, and September,
and once per week during the
rest of the year
Surface Water Monitoring, 15A
NCAC 2B .0508
Temperature
Monitor and Report
3/Week
No change
Surface Water Monitoring, 15A
NCAC 2B .0508
pH
6 — 9 SU
Monitor and Report
3/Week
No change
WQBEL. State WQ standard, 15A
NCAC 2B
Total Nitrogen
Monitor and Report
Monthly
No change
Surface Water Monitoring, 15A
NCAC 2B .0508
Total
Phosphorous
Monitor and Report
Monthly
No change
Surface Water Monitoring, 15A
NCAC 2B .0508
Page 8 of 9

Total Silver
Monitor and Report
Quarterly
Remove requirement
Based on RPA; All values reported
non -detect < 5 ug/L. No
monitoring required. Permittee
shall report to PQL of 1 ug/L
Total Hardness
No requirement
Quarterly monitoring
Upstream and in Effluent
Hardness -dependent dissolved
metals water quality standards
approved in 2016; Pretreatment
facility
Chronic Toxicity
Chronic limit, 1.6%
effluent
No change
WQBEL. No toxics in toxic
amounts. 15A NCAC 2B
Effluent
Pollutant Scan
Three times per
permit cycle
No change; conducted in 2023,
2024, 2025
40 CFR 122
Electronic
Reporting
Electronic
Reporting Special
Condition
No change
In accordance with EPA Electronic
Reporting Rule 2015.
MGD — Million gallons per day, MA - Monthly Average, WA — Weekly Average, DM — Daily Max, QA
— Quarterly Average, DA — Daily Average
13. Public Notice Schedule:
Permit to Public Notice: March 9, 2021
Per 15A NCAC 2H .0109 & .0111, The Division will receive comments for a period of 30 days following
the publication date of the public notice. Any request for a public hearing shall be submitted to the
Director within the 30 days comment period indicating the interest of the party filing such request and the
reasons why a hearing is warranted.
14. Fact Sheet Addendum (if applicable):
The draft was submitted to the Town of North Wilkesboro, EPA Region IV, and the Division's Winston-
Salem Regional Office, Aquatic Toxicology Branch, Ecosystems Branch and Operator Certification
Program for review. No comments were received from any party.
Were there any changes made since the Draft Permit was public noticed (Yes/No): YES
If Yes, list changes and their basis below:
• As the Monitoring Coalition will not be conducting hardness sampling on behalf of the Permittee,
the footnote language in Section A.(1.) has been updated.
• The expiration date for the permit was modified to more closely fit a 5-year permit cycle.
Accordingly, the specified years for the Effluent Pollutant Scans have been modified (2023, 2024,
2025). See Special Condition A. (3.).
15. Fact Sheet Attachments (if applicable):
• RPA Spreadsheet Summary
• BOD and TSS Removal
• Waste Load Allocation Spreadsheet
• Mercury TMDL Spreadsheet
• Toxicity Summary
• Pretreatment Summary
Page 9 of 9

AFFP
Pub Not-NPDES Wastewater Permi
Affidavit of Publication
STATE OF NORTH
CAROLINA } 1 kes
COUNTY OF } L4
Kimberly Cook, being duly sworn, says:
That she is the billing clerk of the Wilkes f printed andatriot,
daily newspaper of general circulation, p
published in North Wilkesboro, County, North Carolina;
that the publication, a copy of which is attached hereto,
was published in the said newspaper on the following
March 17, 2021
SS
That said newspaper was regularly issued and
on those dates.
SIGNED:
a
the billing cleik
Subscribed to and sworn to me this 17th day of March
2021.
Barbara M Daniels, Notary, Guilford, County, North
Carolina 01,2022
My commission expires: February
40097986 40393591
Wren Thedford
NCDEQ-Division of Water Resources
1617 Mail Service Center
Raleigh, NC 27699
Public Notice
North Carolina Environmental
Management CornmissieniNP
DES Unit, 1617 Mail Service Can-
ter Raleigh, NC 27699-1617
Notice of lntent to Issue a PermiNP'_
DES Wastewater
t
NC0020761
Thurman
an Street
WWTP
The North Carolina � � ssio� pro
Management
poses to issue a NPDES wastewa-
ter discharge permit to the
person(s) listed below. Written
regarding t
comments reg g he proposed
until permit will be accepted:dateof this0
.
days after the publish
notice. The Direct�sourcas (DWR)may hold a public r of the NC Divi-
sign of �Jatehearing should there be a significant degree of
public irrteresinfor. Please mail rreat oregL�osts
com-
ments and/or
to DWR at the
bovre+afiddre� t the
In-
terested personsStreet
at 512 N.
Raleigh, circulated DWR h NC 27604l to rev
iew in-
sbury alelg
formation on file. Additional iniorm-
atiorr on NPDES permits and !Ibis
notice may be found on our web -
site: http:L;deq.nc.go► /about divi-
sions/water-resources water-re-
sources-permits?wastewater_
brartch#r>�pdes- tat P ) -
notices,or by calling
01 The Town of North Wilkes-
36
,
borct 1100 Thurman
2�3659} hasre-
questedWilkesboro, N - re
quested renewal of NPDES permit
NC0020761 for its rStreet
Co�,nty.
WWTP, located Wilkes treated mu-
nicipal facility discharges
and industrial wastewater to
the Yadkin River, a class c water
in the Yadkin Pee -Dee River
Basin_ Currently, ammonia and
fecal colifcrm afe water quality lirrt-
ited. This discharge mayaffect fu-
ture allocations into this portion of
the Yadkin River_
March 17, 2021

Freshwater RPA - 95% Probability/95% Confidence Using Metal Translators
MAXIMUM DATA POINTS = 58
REQUIRED DATA ENTRY
Table 1. Project Information
❑ CHECK IF HQW OR ORW WQS
Facility Name
WWTP/WTP Class
NPDES Permit
Outfall
Flow, Qw (MGD)
Receiving Stream
HUC Number
Stream Class
North Wilkesboro WWTP
q
Grade III
NC0020761
001
2.000
Yadkin River
03040101
C
❑ Apply WS Hardness WQC
7Q10s (cfs)
7Q1Ow (cfs)
30Q2 (cfs)
QA (cfs)
1 Q10s (cfs)
196.00
267.00
393.00
683.00
159.23
Effluent Hardness
Upstream Hardness
Combined Hardness Chronic
Combined Hardness Acute
25.33 mg/L (Avg)
25 mg/L (Avg)
25.01 mg/L
25.01 mg/L
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
0.5900
FW
3.2403
ug/L
Chlorides
Aquatic Life
NC
230
FW
Chlorinated Phenolic Compounds
Water Supply
NC
1
A
ug/L
yTotal Phenolic Compounds
Aquatic Life
NC
300
A
ug/L
Chromium III
Aquatic Life
NC
117.7526
FW
905.2705
ug/L
Chromium VI
Aquatic Life
NC
11
FW
16
pg/L
Chromium, Total
Aquatic Life
NC
N/A
FW
N/A
pg/L
Copper
Aquatic Life
NC
7.8820
FW
10.4745
ug/L
Cyanide
Aquatic Life
NC
5
FW
22
10
ug/L
Fluoride
Aquatic Life
NC
1,800
FW
ug/L
Lead
Aquatic Life
NC
2.9423
FW
75.5088
ug/L
Mercury
Aquatic Life
NC
12
FW
0.5
ng/L
Molybdenum
Human Health
NC
2000
HH
ug/L
Nickel
Aquatic Life
NC
37.2379
FW
335.2809
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
0.2965
ug/L
Zinc
Aquatic Life
NC
126.7558
FW
125.7323
ug/L
FW RPA, input
3/1/2021

REASONABLE POTENTIAL ANALYSIS
Effluent Hardness
Date Data
4/26/2016
7/25/2017
10/10/2018
20
28
28
BDL=1/2DL
20
28
28
Results
Std Dev.
Mean
C.V. (default)
n
10th Per value
Average Value
Max. Value
Use "PASTE SPECIAL.
Values" then "COPY"
. Maximum data
points = 58
H2
Upstream Hardness
4.6188
25.3333
0.6000
3
21.60 mg/L
25.33 mg/L
28.00 mg/L
-1-
Date Data
Default
25
BDL=1/2DL
25
Results
Std Dev.
Mean
C.V.
n
10th Per value
Average Value
Max. Value
Use "PASTE SPECIAL
Values" then "COPY"
. Maximum data
points = 58
N/A
25.0000
0.0000
1
25.00 mg/L
25.00 mg/L
25.00 mg/L
FW RPA, data
3/1 /2021

REASONABLE POTENTIAL ANALYSIS
Par01 & Par02
Arsenic
Date Data BDL=1/2DL Results
1 4/26/2016 < 10 5 Std Dev.
2 7/25/2017 < 10 5 Mean
3 10/10/2018 < 10 5 C.V. (default)
4 n
5
6 Mult 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
5.0000
0.6000
3
3.00
5.0 ug/L
15.0 ug/L
-2-
FW RPA, data
3/1 /2021

REASONABLE POTENTIAL ANALYSIS
Par03
Beryllium
Date Data BDL=1/2DL Results
1 4/26/2016 < 5 2.5 Std Dev.
2 7/25/2017 < 5 2.5 Mean
3 10/10/2018 < 5 2.5 C.V. (default)
4 n
5
6 Mult 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
Par04
Cadmium
0.0000
2.5000
0.6000
3
3.00
2.50 ug/L
7.50 ug/L
-3-
Date Data BDL=1/2DL Results
1 4/26/2016 < 2 1 Std Dev.
2 7/25/2017 < 2 1 Mean
3 10/10/2018 < 2 1 C.V. (default)
4 7/10/2017 < 2 1 n
5 7/11/2017 < 2 1
6 7/12/2017 < 2 1 Mult Factor =
7 7/13/2017 < 2 1 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
1.0000
0.6000
7
2.01
1.000 ug/L
2.010 ug/L
FW RPA, data
3/1 /2021

REASONABLE POTENTIAL ANALYSIS
Par07
Total Phenolic Compounds
Date Data BDL=1/2DL Results
1 4/26/2016 147 147 Std Dev.
2 7/25/2017 16 16 Mean
3 10/10/2018 14 14 C.V. (default)
4 n
5
6 Mult 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
Par10
Chromium, Total
76.2168
59.0000
0.6000
3
3.00
147.0 ug/L
441.0 ug/L
-4-
Date Data BDL=1/2DL Results
1 4/26/2016 < 5 2.5 Std Dev.
2 7/25/2017 < 5 2.5 Mean
3 10/10/2018 < 5 2.5 C.V. (default)
4 7/10/2017 < 5 2.5 n
5 7/11/2017 < 5 2.5
6 7/12/2017 < 5 2.5 Mult Factor =
7 7/13/2017 < 5 2.5 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
7
2.01
2.5 pg/L
5.0 pg/L
FW RPA, data
3/1 /2021

REASONABLE POTENTIAL ANALYSIS
Pall
Copper
Date Data BDL=1/2DL Results
1 4/26/2016 9 9 Std Dev.
2 7/25/2017 4 4 Mean
3 10/10/2018 4 4 C.V. (default)
4 7/10/2017 8 8 n
5 7/11/2017 4 4
6 7/12/2017 4 4 Mult Factor =
7 7/13/2017 5 5 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
Par12
Cyanide
2.1492
5.4286
0.6000
7
2.01
9.00 ug/L
18.09 ug/L
-5-
Date Data BDL=1/2DL Results
1 4/26/2016 < 5 5 Std Dev.
2 7/25/2017 < 5 5 Mean
3 10/10/2018 < 5 5 C.V. (default)
4 7/10/2017 < 5 5 n
5 7/11/2017 6.5 5
6 7/12/2017 < 5 5 Mult Factor =
7 7/13/2017 < 5 5 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
5.00
0.6000
7
2.01
5.0 ug/L
10.1 ug/L
FW RPA, data
3/1 /2021

REASONABLE POTENTIAL ANALYSIS
Par14
Lead
Date
4/26/2016 < 10
7/25/2017 16
10/10/2018 < 10
7/10/2017 < 10
7/11/2017 < 10
7/12/2017 < 10
7/13/2017 < 10
BDL=1/2DL Results
5 Std Dev.
16 Mean
5 C.V. (default)
5 n
5
5 Mult Factor =
5 Max. Value
Max. Pred Cw
Use "PASTE SPECIAL.
Values" then "COPY"
. Maximum data
points = 58
Par16
Molybdenum
4.1576
6.5714
0.6000
7
2.01
16.000 ug/L
32.160 ug/L
-6-
Date Data BDL=1/2DL Results
1 7/10/2017 < 5 2.5 Std Dev.
2 7/11/2017 < 5 2.5 Mean
3 7/12/2017 < 5 2.5 C.V. (default)
4 7/13/2017 < 5 2.5 n
5
6 Mult 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
2.5 ug/L
6.5 ug/L
FW RPA, data
3/1 /2021

REASONABLE POTENTIAL ANALYSIS
Par17 & Par18
Nickel
Date Data BDL=1/2DL
5
5
5
5
5
5
5
4/26/2016 <
7/25/2017 <
10/10/2018 <
7/10/2017 <
7/11/2017 <
7/12/2017 <
7/13/2017 <
10
10
10
10
10
10
10
Results
Std Dev.
Mean
C.V. (default)
n
Mult Factor =
Max. Value
Max. Pred Cw
Use "PASTE
SPECIAL -
Values" then
"COPY" .
Maximum data
points = 58
Par19
Selenium
0.0000
5.0000
0.6000
7
2.01
5.0 pg/L
10.1 pg/L
-7-
Date Data BDL=1/2DL
5
5
5
5
5
5
5
4/26/2016
7/25/2017
10/10/2018
7/10/2017
7/11/2017
7/12/2017
7/13/2017
10
10
10
10
10
10
10
Results
Std Dev.
Mean
C.V. (default)
n
Mult Factor =
Max. Value
Max. Pred Cw
Use "PASTE
SPECIAL -Values"
then "COPY" .
Maximum data
points = 58
0.0000
5.0000
0.6000
7
2.01
5.0 ug/L
10.1 ug/L
FW RPA, data
3/1 /2021

REASONABLE POTENTIAL ANALYSIS
Par20
Silver
Date Data BDL=1/2DL
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
4/26/2016
7/25/2017
10/10/2018
4/10/2017
7/5/2017
7/10/2017
7/11/2017
7/12/2017
7/13/2017
10/3/2017
1 /3/2018
4/17/2018
7/17/2018
10/9/2018
1 /9/2019
4/4/2019
7/9/2019
10/8/2019
1/7/2020
4/7/2020
7/7/2020
10/6/2020
1 /5/2021
Results
Std Dev.
Mean
C.V.
n
Mult Factor =
Max. Value
Max. Pred Cw
Use "PASTE SPECIAL.
Values" then "COPY"
. Maximum data
points = 58
Par21
Zinc
0.0000
2.5000
0.0000
23
1.00
2.500 ug/L
2.500 ug/L
-8-
Date Data BDL=1/2DL
86
37
27
14
13
16
16
4/26/2016
7/25/2017
10/10/2018
7/10/2017
7/11/2017
7/12/2017
7/13/2017
86
37
27
14
13
16
16
Results
Std Dev.
Mean
C.V. (default)
n
Mult Factor =
Max. Value
Max. Pred Cw
Use "PASTE SPECIAL.
Values" then "COPY"
. Maximum data
points = 58
26.2388
29.8571
0.6000
7
2.01
86.0 ug/L
172.9 ug/L
FW RPA, data
3/1 /2021

North Wilkesboro WWTP
NC0020761
Freshwater RPA - 95% Probability/95% Confidence Using Metal Translators
MAXIMUM DATA POINTS = 58
Qw (MGD) = 2.0000
1Q1OS (cfs) = 159.23
7Q1OS (cfs) = 196.00
7Q1OW (cfs) = 267.00
30Q2 (cfs) = 393.00
Avg. Stream Flow, QA (cfs) = 683.00
Receiving Stream: Yadkin River HUC 03040101
WWTP/WTP Class:
IWC% @ 1Q1OS =
IWC% @ 7Q1OS =
IWC% @ 7Q1OW =
IWC% @ 30Q2 =
IW%C@QA=
Stream Class:
Grade III
1.909690137
1.557006529
1.147723066
0.782630649
0.451829179
C
Outfall 001
Qw = 2 MGD
COMBINED HARDNESS (mg/L)
Acute = 25.01 mg/L
Chronic = 25.01 mg/L
PARAMETER
TYPE
NC STANDARDS OR EPA CRITERIA
_1
n
REASONABLE POTENTIAL RESULTS
RECOMMENDED ACTION
Chronic Stapda d AcuteoCi
n # Det. Max Pred Cw Allowable Cw
Arsenic
Arsenic
C
C
150 FW(7Q10s) 340
10 HH/WS(Qavg)
ug/L
ug/L
3 0
Note: n < 9
Limited data set
15.0
C.V. (default)
NO DETECTS
Acute (FW): 17,803.9
Chronic (FW):9,633.9
Max MDL= 10
Chronic (HH): 2,213.2
Max MDL = 10
No RP, Predicted Max < 50% of Allowable Cw - No
Monitoring required
Beryllium
NC
6.5 FW(7Q10s) 65
ug/L
3 0
Note: n < 9
Limited data set
7.50
C.V. (default)
NO DETECTS
Acute: 3,403.69
_ _ _ _ _ _ _ _ _ _ _ _ _
Chronic: 417.47
Max MDL = 5
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _
No RP, Predicted Max < 50% of Allowable Cw - No
Monitoring required
Cadmium
NC
0.5900 FW(7Q10s) 3.2403
ug/L
7 0
Note: n < 9
Limited data set
2.010
C.V. (default)
NO DETECTS
Acute: 169.678
_ _ _ _ _ _ _ _ _ _ _ _ _
Chronic: 37.891
Max MDL = 2
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _
No RP, Predicted Max < 50% of Allowable Cw - No
Monitoring required
Total Phenolic Compounds
NC
300 A(30Q2)
ug/L
3 3
Note: n < 9
Limited data set
441.0
C.V. (default)
Acute: NO WQS
_ _ _ _ _ _ _ _ _ _ _ _
Chronic: 38,332.3
No value > Allowable Cw
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _
No RP, Predicted Max < 50% of Allowable Cw - No
Monitoring required
Chromium III
NC
117.7526 FW(7Q10s) 905.2705
µg/L
0 0
N/A
Acute: 47,404.1
--_ _ ---_ _
---------------------------------
Chronic: 7,562.8
Chromium VI
NC
11 FW(7Q10s) 16
µg/L
0 0
N/A
Acute: 837.8
--_ _ ----_ _
--706.5--------------------------------
Chronic:
Chromium, Total
NC
µg/L
7 0
Note: n < 9
Limited data set
5.0
C.V. (default)
NO DETECTS
Max reported value = 2.5
Max MDL = 5
a: No monitoring required if all Total Chromium
samples are < 5 pg/L or Pred. max for Total Cr is <
allowable Cw for Cr VI.
Copper
NC
7.8820 FW(7Q10s) 10.4745
ug/L
7 7
Note: n < 9
Limited data set
18.09
C.V. (default)
Acute: 548.49
_ _ _ _ _ _ _ _ _ _ _ _ _
Chronic: 506.23
No value > Allowable Cw
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _
No RP, Predicted Max < 50% of Allowable Cw - No
Monitoring required
Cyanide
NC
5 FW(7Q10s) 22
10
ug/L
7 1
Note: n < 9
Limited data set
10.1
C.V. (default)
Acute: 1,152.0
____ _ ______ _____
Chronic: 321.1
No value > Allowable Cw
_ _ _ _ _ _ _ _ _ _ _ _ _ _
No RP, Predicted Max < 50% of Allowable Cw - No
Monitoring required
Page 1 of 2
FW RPA, rpa
3/1/2021

North Wilkesboro WWTP
NC0020761
Freshwater RPA - 95% Probability/95% Confidence Using Metal Translators
Outfall 001
Qw = 2 MGD
Lead
NC
2.9423 FW(7Q10s) 75.5088
ug/L
7 1
Note: n < 9
Limited data set
32.160
C.V. (default)
Acute: 3,953.979
_ _ _ _ _ _ _ _ _ _ _ _ _ _
Chronic: 188.972
No value > Allowable Cw
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _
No RP, Predicted Max < 50% of Allowable Cw - No
Monitoring required
Acute: NO WQS
Molybdenum
NC
2000 HH(7Q10s)
ug/L
4 0
6.5
_ _ _ _ _ _ _ _ _ _ _ _ _ _
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _
Note: n < 9
C.V. (default)
Chronic: 128,451.6
No RP, Predicted Max < 50% of Allowable Cw - No
Limited data set
NO DETECTS
Max MDL = 5
Monitoring required
Acute (FW): 17,556.8
Nickel
NC
37.2379 FW(7Q10s) 335.2809
µg/L
_ _ _ _ _ _ _ _ _ _ _
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _
7 0
10.1
Chronic (FW): 2,391.6
No RP, Predicted Max < 50% of Allowable Cw - No
Note: n < 9
C.V. (default)
Max MDL = 10
Monitoring required
Nickel
NC
25.0000 WS(7Q10s)
µg/L
Limited data set
NO DETECTS
Chronic (WS): 1,605.6
Max MDL= 10
Acute: 2,932.4
Selenium
NC
5 FW(7Q10s) 56
ug/L
7 0
10.1
____ _ ______ _____
_ _ _ _ _ _ _ _ _ _ _ _ _ _
Note: n < 9
C.V. (default)
Chronic: 321.1
No RP, Predicted Max < 50% of Allowable Cw - No
Limited data set
NO DETECTS
Max MDL = 10
Monitoring required
Acute: 15.528
Silver
NC
0.06 FW(7Q10s) 0.2965
ug/L
23 0
2.500
____ _ ______ _____
_ _ _ _ _ _ _ _ _ _ _______
Chronic: 3.854
All values reported non -detect < 5 ug/L. No
monitoring required. Permittee shall report to PQL of
NO DETECTS
Max MDL = 5
1 ug/L
Acute: 6,583.9
Zinc
NC
126.7558 FW(7Q10s) 125.7323
ug/L
7 7
172.9
_ _ _ _ _ _ _ _ _ _ _ _ _
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _
Note: n < 9
C.V. (default)
Chronic: 8,141.0
No RP, Predicted Max < 50% of Allowable Cw - No
Limited data set
No value > Allowable Cw
Monitoring required
Page 2 of 2
FW RPA, rpa
3/1/2021

Permit No. NC0020761
NPDES Implementation of Instream Dissolved Metals Standards - Freshwater Standards
The NC 2007-2015 Water Quality Standard (WQS) Triennial Review was approved by the NC
Environmental Management Commission (EMC) on November 13, 2014. The US EPA subsequently
approved the WQS revisions on April 6, 2016, with some exceptions. Therefore, metal limits in draft
permits out to public notice after April 6, 2016 must be calculated to protect the new standards - as
approved.
Table 1. NC Dissolved Metals Water Quality Standards/Aquatic Life Protection
Parameter
Acute FW, µg/1
(Dissolved)
Chronic FW, 14/1
(Dissolved)
Acute SW, 14/1
(Dissolved)
Chronic SW, µg/1
(Dissolved)
Arsenic
340
150
69
36
Beryllium
65
6.5
---
---
Cadmium
Calculation
Calculation
40
8.8
Chromium III
Calculation
Calculation
---
---
Chromium VI
16
11
1100
50
Copper
Calculation
Calculation
4.8
3.1
Lead
Calculation
Calculation
210
8.1
Nickel
Calculation
Calculation
74
8.2
Silver
Calculation
0.06
1.9
0.1
Zinc
Calculation
Calculation
90
81
Table 1 Notes:
1. FW= Freshwater, SW= Saltwater
2. Calculation = Hardness dependent standard
3. Only the aquatic life standards listed above are expressed in dissolved form. Aquatic life
standards for Mercury and selenium are still expressed as Total Recoverable Metals due to
bioaccumulative concerns (as are all human health standards for all metals). It is still necessary
to evaluate total recoverable aquatic life and human health standards listed in 15A NCAC
2B.0200 (e.g., arsenic at 10 µg/1 for human health protection; cyanide at 5 µg/L and fluoride at
1.8 mg/L for aquatic life protection).
Table 2. Dissolved Freshwater Standards for Hardness -Dependent Metals
The Water Effects Ratio (WER) is equal to one unless determined otherwise under 15A
NCAC 02B .0211 Subparagraph (11)(d)
Metal
NC Dissolved Standard, µg/I
Cadmium, Acute
WER*{1.1366724ln hardness](0.041838)} • e^{0.9151 [ln hardness]-3.1485}
Cadmium, Acute Trout waters
WER*{1.136672-[ln hardness](0.041838)} • e^{0.9151[ln hardness]-3.6236}
Cadmium, Chronic
WER* { 1.101672-[ln hardness](0.041838)} • e^{0.7998[In hardness]-4.4451 }
Chromium III, Acute
WER*0.316 • e^{0.8190[ln hardness]+3.7256}
Chromium III, Chronic
WER*0.860 • e^{0.8190[ln hardness]+0.6848}
Copper, Acute
WER*0.960 • e^{0.9422[ln hardness]-1.700}
Copper, Chronic
WER*0.960 • e^{0.8545[ln hardness]-1.702}
Lead, Acute
WER*{1.462034ln hardness](0.145712)} • e^{1.273[In hardness]-1.460}
Lead, Chronic
WER*{1.46203-[ln hardness](0.145712)} • e^{1.273[In hardness]-4.705}
Nickel, Acute
WER*0.998 • e^{0.8460[ln hardness]+2.255}
Nickel, Chronic
WER*0.997 • e^{0.8460[ln hardness]+0.0584}
Page 1 of 4

Permit No. NC0020761
Silver, Acute
WER*0.85 • e^{1.72[ln hardness]-6.59}
Silver, Chronic
Not applicable
Zinc, Acute
WER*0.978 • e^{0.8473[ln hardness]+0.884}
Zinc, Chronic
WER*0.986 • e^{0.8473[ln hardness]+0.884}
General Information on the Reasonable Potential Analysis (RPA)
The RPA process itself did not change as the result of the new metals standards. However, application of
the dissolved and hardness -dependent standards requires additional consideration in order to establish the
numeric standard for each metal of concern of each individual discharge.
The hardness -based standards require some knowledge of the effluent and instream (upstream) hardness
and so must be calculated case -by -case for each discharge.
Metals limits must be expressed as `total recoverable' metals in accordance with 40 CFR 122.45(c). The
discharge -specific standards must be converted to the equivalent total values for use in the RPA
calculations. We will generally rely on default translator values developed for each metal (more on that
below), but it is also possible to consider case -specific translators developed in accordance with
established methodology.
RPA Permitting Guidance/WQBELs for Hardness -Dependent Metals - Freshwater
The RPA is designed to predict the maximum likely effluent concentrations for each metal of concern,
based on recent effluent data, and calculate the allowable effluent concentrations, based on applicable
standards and the critical low -flow values for the receiving stream.
If the maximum predicted value is greater than the maximum allowed value (chronic or acute), the
discharge has reasonable potential to exceed the standard, which warrants a permit limit in most cases. If
monitoring for a particular pollutant indicates that the pollutant is not present (i.e. consistently below
detection level), then the Division may remove the monitoring requirement in the reissued permit.
1. To perform a RPA on the Freshwater hardness -dependent metals the Permit Writer compiles the
following information:
• Critical low flow of the receiving stream, 7Q10 (the spreadsheet automatically calculates
the 1Q10 using the formula 1Q10 = 0.843 (s7Q10, cfs) 0.993
• Effluent hardness and upstream hardness, site -specific data is preferred
• Permitted flow
• Receiving stream classification
2. In order to establish the numeric standard for each hardness -dependent metal of concern and for
each individual discharge, the Permit Writer must first determine what effluent and instream
(upstream) hardness values to use in the equations.
The permit writer reviews DMR's, Effluent Pollutant Scans, and Toxicity Test results for any
hardness data and contacts the Permittee to see if any additional data is available for instream
hardness values, upstream of the discharge.
If no hardness data is available, the permit writer may choose to do an initial evaluation using a
default hardness of 25 mg/L (CaCO3 or (Ca + Mg)). Minimum and maximum limits on the
hardness value used for water quality calculations are 25 mg/L and 400 mg/L, respectively.
If the use of a default hardness value results in a hardness -dependent metal showing reasonable
potential, the permit writer contacts the Permittee and requests 5 site -specific effluent and
upstream hardness samples over a period of one week. The RPA is rerun using the new data.
Page 2 of 4

Permit No. NC0020761
The overall hardness value used in the water quality calculations is calculated as follows:
Combined Hardness (chronic)
= (Permitted Flow, cfs *Avg. Effluent Hardness, mg/L) + (s7Q10, cfs *Avg. Upstream Hardness, mg/L)
(Permitted Flow, cfs + s7Q10, cfs)
The Combined Hardness for acute is the same but the calculation uses the 1Q10 flow.
3. The permit writer converts the numeric standard for each metal of concern to a total recoverable
metal, using the EPA Default Partition Coefficients (DPCs) or site -specific translators, if any
have been developed using federally approved methodology.
EPA default partition coefficients or the "Fraction Dissolved" converts the value for
dissolved metal at laboratory conditions to total recoverable metal at in -stream
ambient conditions. This factor is calculated using the linear partition coefficients
found in The Metals Translator: Guidance for Calculating a Total Recoverable
Permit Limit from a Dissolved Criterion (EPA 823-B-96-007, June 1996) and the
equation:
Cdiss = 1
Ctotal 1 + { [Kpo] [SS(1
+1 [10 6]
Where:
ss = in -stream suspended solids concentration [mg/1], minimum of 10 mg/L used,
and
Kpo and a = constants that express the equilibrium relationship between dissolved
and adsorbed forms of metals. A list of constants used for each hardness -dependent
metal can also be found in the RPA program under a sheet labeled DPCs.
4. The numeric standard for each metal of concern is divided by the default partition coefficient (or
site -specific translator) to obtain a Total Recoverable Metal at ambient conditions.
In some cases, where an EPA default partition coefficient translator does not exist (ie. silver), the
dissolved numeric standard for each metal of concern is divided by the EPA conversion factor to
obtain a Total Recoverable Metal at ambient conditions. This method presumes that the metal is
dissolved to the same extent as it was during EPA's criteria development for metals. For more
information on conversion factors see the June, 1996 EPA Translator Guidance Document.
5. The RPA spreadsheet uses a mass balance equation to determine the total allowable concentration
(permit limits) for each pollutant using the following equation:
Ca = (s7Q10 + Qw) (Cwqs) — (s7Q10) (Cb)
Qw
Where: Ca = allowable effluent concentration (µg/L or mg/L)
Cwqs = NC Water Quality Standard or federal criteria (µg/L or mg/L)
Cb = background concentration: assume zero for all toxicants except NH3* (µg/L or mg/L)
Qw = permitted effluent flow (cfs, match s7Q10)
s7Q10 = summer low flow used to protect aquatic life from chronic toxicity and human
health through the consumption of water, fish, and shellfish from noncarcinogens (cfs)
* Discussions are on -going with EPA on how best to address background concentrations
Flows other than s7Q10 may be incorporated as applicable:
1Q10 = used in the equation to protect aquatic life from acute toxicity
Page 3 of 4

Permit No. NC0020761
QA = used in the equation to protect human health through the consumption of water,
fish, and shellfish from carcinogens
30Q2 = used in the equation to protect aesthetic quality
6. The permit writer enters the most recent 2-3 years of effluent data for each pollutant of concern.
Data entered must have been taken within four and one-half years prior to the date of the permit
application (40 CFR 122.21). The RPA spreadsheet estimates the 95th percentile upper
concentration of each pollutant. The Predicted Max concentrations are compared to the Total
allowable concentrations to determine if a permit limit is necessary. If the predicted max exceeds
the acute or chronic Total allowable concentrations, the discharge is considered to show
reasonable potential to violate the water quality standard, and a permit limit (Total allowable
concentration) is included in the permit in accordance with the U.S. EPA Technical Support
Document for Water Quality -Based Toxics Control published in 1991.
7. When appropriate, permit writers develop facility specific compliance schedules in accordance
with the EPA Headquarters Memo dated May 10, 2007 from James Hanlon to Alexis Strauss on
40 CFR 122.47 Compliance Schedule Requirements.
8. The Total Chromium NC WQS was removed and replaced with trivalent chromium and
hexavalent chromium Water Quality Standards. As a cost savings measure, total chromium data
results may be used as a conservative surrogate in cases where there are no analytical results
based on chromium III or VI. In these cases, the projected maximum concentration (95th %) for
total chromium will be compared against water quality standards for chromium III and
chromium VI.
9. Effluent hardness sampling and instream hardness sampling, upstream of the discharge, are
inserted into all permits with facilities monitoring for hardness -dependent metals to ensure the
accuracy of the permit limits and to build a more robust hardness dataset.
10. Hardness and flow values used in the Reasonable Potential Analysis for this permit included:
Parameter
Value
Comments (Data Source)
Average Effluent Hardness (mg/L)
[Total as, CaCO3 or (Ca+Mg)]
25.33
Average from 2016, 2017 and 2018
Effluent Pollutant Scans
Average Upstream Hardness (mg/L)
[Total as, CaCO3 or (Ca+Mg)]
25
Default Value
7Q10 summer (cfs)
196
NPDES Files
1Q10 (cfs)
159.23
Calculated in RPA
Permitted Flow (MGD)
2.0
NPDES Files
Date: 3/1/2021
Permit Writer: Nick Coco
Page 4 of 4

NC0020761 North Wilkesboro WWTP 3/1/2021
BOD monthly removal rate
Month RR (%) Month RR (%)
February-17
March-17
April-17
May-17
June-17
July-17
August-17
September-17
October-17
November-17
December-17
January-18
February-18
March-18
April-18
May-18
June-18
July-18
August-18
September-18
October-18
November-18
December-18
January-19
February-19
March-19
April-19
May-19
June-19
July-19
95.70
96.64
96.10
96.36
96.74
95.76
94.46
96.50
95.75
96.90
96.48
96.08
95.99
95.87
94.79
95.83
95.94
96.41
95.42
95.55
96.78
96.65
96.08
96.49
96.17
96.05
95.91
95.59
96.28
96.17
August-19
September-19
October-19
November-19
December-19
January-20
February-20
March-20
April-20
May-20
June-20
July-20
August-20
September-20
October-20
November-20
December-20
January-21
February-21
March-21
April-21
May-21
June-21
July-21
August-21
September-21
October-21
November-21
December-21
January-22
Overall BOD removal rate
97.12
96.63
96.78
96.68
96.99
97.41
96.68
97.05
95.96
96.70
96.76
97.13
96.49
96.40
97.04
97.22
96.10
96.31
TSS monthly removal rate
Month RR (%) Month RR (%)
February-17
March-17
April-17
May-17
June-17
July-17
August-17
September-17
October-17
November-17
December-17
January-18
February-18
March-18
April-18
May-18
June-18
July-18
August-18
September-18
October-18
November-18
December-18
January-19
February-19
March-19
April-19
May-19
June-19
July-19
92.58
93.76
94.04
93.98
96.19
96.92
96.41
97.01
96.69
97.83
96.75
96.56
95.80
96.53
95.81
97.00
97.34
97.11
94.68
96.10
96.34
95.73
95.07
95.18
95.91
96.69
96.91
97.94
96.17
98.15
August-19
September-19
October-19
November-19
December-19
January-20
February-20
March-20
April-20
May-20
June-20
July-20
August-20
September-20
October-20
November-20
December-20
January-21
February-21
March-21
April-21
May-21
June-21
July-21
August-21
September-21
October-21
November-21
December-21
January-22
Overall TSSD removal rate
98.18
97.87
97.35
98.11
98.22
98.77
98.32
98.19
97.36
95.78
98.74
98.45
97.05
95.56
95.97
96.27
95.29
96.57

3/1/21 WQS = 12 ng/L
Facility Name
North Wilkesboro WWTP/NC0020761
/Permit No. :
MERCURY WQBEL/TBEL EVALUATION V:2013-6
Total Mercury 1631E PQL = 0.5 ng/L 7Q10s =
Date Modifier Data Entry Value Permitted Flow =
7/25/17
10/10/18
5.25
9.54
No Limit Required
MMP Required
5.25
196.000
2.000
cfs
WQBEL = 770.71 ng/L
47 ng/L
5.3 ng/L - Annual Average for 2017
9.54 9.5 ng/L - Annual Average for 2018

North Wilkesboro WWTP/NC0020761
Mercury Data Statistics (Method 1631E)
2017
2018
# of Samples
1
1
Annual Average, ng/L
5.3
9.5
Maximum Value, ng/L
5.25
9.54
TBEL, ng/L
47
WQBEL, ng/L
770.7

NH3/TRC WLA Calculations
Facility: North Wilkesboro WWTP
PermitNo. NC0020761
Prepared By: Nick Coco
Enter Design Flow (MGD):
Enter s7Q10 (cfs):
Enter w7Q10 (cfs):
2
196
267
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)
196
2
3.1
17.0
0
1.56
1092
UV used. No limit.
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)
196
2
3.1
1.0
0.22
1.56
50.3
Less stringent than existing limit. Maintain limit.
Ammonia (Winter)
Monthly Average Limit (mg NH3-N/I)
w7Q10 (CFS)
200/100mI DESIGN FLOW (MGD)
DESIGN FLOW (CFS)
STREAM STD (MG/L)
64.23 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
267
2
3.1
1.8
0.22
1.15
137.9
Less stringent than existing limit. Maintain limit.
Ammonia (as NH3-N)
1. If Allowable Conc > 35 mg/I, Monitor Only
2. Monthly Avg limit x 3 = Weekly Avg limit (Municipals)
3. Monthly Avg limit x 5 = Daily Max limit (Non-Munis)
If the allowable ammonia concentration is > 35 mg/L, no limit shall be imposed
Fecal Coliform
1. Monthly Avg limit x 2 = 400/100 ml = Weekly Avg limit (Municipals) = Daily Max limit (Non -Muni)

Attachment A —Request for Missing Information
Table 2. EPA Application Form 2A Missing Information
40 CFR 122.21(j)(1)
1.1 Email address of facility contact sperry@north-wilkesboro,com
1.2 Applicant email address [e-mail]
1.3 Email address of the organization transporting the discharge for treatment prior to discharge NA
1.4 Email address of the organization receiving the discharge for treatment prior to discharge NA
15 ' Do you intend to request or renew one or more of the variances authorized at 40 CFR 122.21(n)? (Check all that apply. Consult
with your NPDES permitting authority to determine what information needs to be submitted and when.)
X❑
Discharges into marine waters (CWA Section Water quality related effluent limitation (CWA
Section 302(b)(2))
301(h))
Not applicable
1.6 Email address of contractor responsible for operational or maintenance aspects of the treatment works NA
1.7 Indicate the number of SIUs and NSCIUs that discharge to the POTW.
Number of Sills
2
40 CFR 122.22(a) and (d)
Number of Ms
2
Certification Statement
I certify under penalty of law that this document and ail attachments were prepared under my direction or supervision in
accordance with a system designed to assure that qualified personnel properly gather and evaluate the information submitted.
Based on my inquiry of the person or persons who manage the system, or those persons directly responsible for gathering the
information, the information submitted is, to the best of my knowledge and belief, true, accurate, and complete. I am aware that
there are significant penalties for submitting false information, including the possibility of fine and imprisonment for knowing
violations.
Name (print or type first and last name) Scott Perry
Official title ORC
Date signed
D3ay ;/

NPDES/Aquifer
Protection
Permitting Unit
Pretreatment Information
Request
Form
PERMIT WRITER COMPLETES
THIS PART:
PERMIT WRITERS - AFTER you get this form back
Check
all
that
apply
from PERCS:
Notify PERCS if LTMP/STMP data
Date of Request
3/8/2021
municipal renewal
X
- we said should
be on DMRs is not really there, so we can get it for
Requestor
Nicholas Coco
new industries
you (or NOV POTW).
Facility Name
North Wilkesboro WWTP
WWTP expansion
- Notify PERCS if you want us to keep a specific POC
Permit Number
NC0020761
Speculative limits
in LTMP/STMP so you will have data for next permit
Region
Winston-Salem
stream reclass.
renewal.
PERCS draft fact sheet, RPA.
Basin
Yadkin -Pee Dee
outfall relocation
=mail permit,
- Send PERCS paper copy of permit (w/o NPDES
7Q10 change
boilerplate), cover letter, final fact sheet. Email RPA if
other
changes.
other
check
applicable PERCS
staff:
Other Comments to
PERCS:
BRD, CPF, CTB, FRB,
TAR
Facility is rated 2.0 MGD
wtih 2 CIUs listed in its application.
i
CHO, HIW, LTN, LUM,
NES, NEW, ROA, YAD
PERCS
Status
PRETREATMENT
of Pretreatment
STAFF COMPLETES THIS
Program (check all that apply)
PART:
1) facility has no SIU's,
does have Division approved
Pretreatment Program that
is INACTIVE
2) facility has no SIU's,
does not have Division approved
Pretreatment Program
-I
3) facility has SIUs
and DWQ approved Pretreatment
Program (list "DEV" if program
still under development)
3a) Full Program
with LTMP
-I
3b) Modified Program
with STMP
4) additional conditions
regarding Pretreatment attached
or listed below
Flow, MGD
Permitted
Actual
Time
period for Actual
STMP time frame:
Industrial
0.0845
0.0489
Most recent:
2018
Uncontrollable
n/a
0.9991
Next Cycle:
2021
POC in LTMP/
STMP
Parameter of
Concern (POC)
Check List
POC due to
NPDES/ Non-
Disch Permit
Limit
Required by EPA*
Required
by 503
Sludge**
POC due
to SIU***
POTW POC
(Explain
below)****
STMP
Effluent
Freq
LTMP
Effluent
Freq
BOD
-I
-I
Q
TSS
-I
-I
Q
Q = Quarterly
NH3
-I
Q
M = Monthly
Arsenic
Al
Q
Al
Cadmium
Al
Al
Al
Q
Al
Chromium
Al
Al
Q
Ai
Copper
Al
Al
Al
Q
Cyanide
Al
Q
Is all data on DMRs?
Al
Lead
Al
Al
Al
Q
YES
-I
Mercury
Al
Q
NO (attach data)
Molybdenum
Al
Q
Al
Nickel
Al
Al
Al
Q
Silver
Al
Q
Selenium
Al
Q
Al
Zinc
Al
-I
Al
Q
Is data in spreadsheet?
Total Phosphorus
Q
YES (email to writer)
Total Nitrogen
Q
NO
-I
Q
Q
Q
Q
*Always in the LTMP/STMP ** Only in LTMP/STMP if sludge land app or composte (dif POCs for incinerators)
*** Only in LTMP/STMP while SIU still discharges to POTW **** Only in LTMP/STMP when pollutant is still of concern to POTW
Comments to Permit W riter (ex., explanation of any POCs; info you have on IU related investigations into NPDES problems):
PERC NPDES_Pretreatment.request.form.may2016
Revised: July 24, 2007

Whole Effluent Toxicity Testing and Self Monitoring Summary
North Harnett Regional WWTP NC0021636/001 County: Harnett
Ceri7dPF Begin: 11/1/2017 chr lim 1.6% @ 5.6M + NonComp: Single
Region: FRO
7Q10: 550.0
Basin: CPF07 Jan Apr Jul Oct
PF: 1.6 IWC: 1.6 Freq: Q
SOC_JOC:
J F M A M J J A S 0 N D
2017 Pass - - Pass 2.3(P) - - Pass - - Pass -
2018 Pass - - >8.4(P) Pass - - Pass - - Pass -
2019 Pass - - Pass >8.4(P) - - Pass - - Pass -
2020 >8.4(P) Pass - - Pass - - Pass - - Pass -
North Wilkesboro WWTP, Thurman St NC0020761/001
County: Wilkes Region: WSRO
Basin: YADO4 Jan Apr Jul Oct
Ceri7dPF Begin: 5/1/2015 chr lim: 1.6% NonComp: Single 7Q10: 196.0 PF: 2.0 IWC: 1.5 Freq: Q
SOC JOC:
J F M A M J J A S 0 N D
2017 Pass - - Pass - - Pass >6(P) - - Pass -
2018 Pass - - Pass - - Pass - - Pass >6.4(P) -
2019 >6.4(P) Pass - - Pass - - Pass - - Pass -
2020 Pass - - Pass - - Pass - - Pass -
Norwood WTP NC0088676/001 County: Stanly Region: MRO Basin: YADO8 Jan Apr Jul Oct
Ceri7dPF Begin: 12/1/2017 Chr Monit: 90% - rer NonComp: 7010: PF: 0.032 IWC: Freq: Q
SOC JOC:
2017
2018
2019
2020
J F M A M J
H
H
H
H
H
H
H
H
J A S 0 N D
H - - H -
H - - H -
H - - H -
H - - H -
Norwood WWTP NC0021628/001 County: Stanly Region: MRO Basin: YAD14 Mar Jun Sep Dec
Ceri7dPF Begin: 2/1/2009 chr lim: 2.7% NonComp: Single 7Q10: 42.0 PF: 0.75 IWC: 2.68 Freq: Q
SOC JOC:
J F M A M J J A S 0 N D
2017 - - Pass - - Pass - - Pass - - Pass
2018 - - Pass - - Pass - - Pass - - Pass
2019 - - Pass - - Pass - - Pass - - Pass
2020 - - Pass - - Pass - - Pass - - Pass
NW WTP Hood Creek- Brunswick NC0057533/001 County: Brunswick Region: WIRO Basin: CPF17 Feb May Aug Nov
Ceri7dPF Begin: 4/1/2018 Chr Monit: 90% NonComp: 7Q10: PF: IWC: Freq: Q
SOC JOC:
J F M A M J J A S 0 N
2017 - Fail - - Pass - - Fail - - Fail
2018 - Fail - - Pass - - Fail - - Fail
2019 - Pass - - Fail - - Pass - - Fail >100(P)
2020 - Fail - - Fail - - Fail - - Pass
Oakboro WWTP-001 NC0043532/001
Ceri7dPF Begin: 12/1/2018 chr lim: 30%
County: Stanly
NonComp: Single
Region: MRO
7Q10: 3.3
Basin: YAD13 Jan Apr Jul Oct
PF: 0.9 IWC: 29.71 Freq: Q
SOC_JOC:
2017
2018
2019
2020
J F M A M J
H
H
H
H
H
H
H
H
1 A S 0 N D
H - - H -
H - - H -
H - - H -
H - - H -
Legend: P= Fathead minnow (Pimphales promelas), H=No Flow (facility is active), s = Split test between Certified Labs
Page 70 of 104

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 ICI J 2 IS I 3 I NC0020761 I11 121 20/01/08 117
Type
18 [
I I I I I
Inspector Fac Type
19 G I 201
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 166
Inspection Work Days Facility Self -Monitoring Evaluation Rating B1 QA Reserved
671I 7° I I 711I 72 I N I 73I I 174
L� 1 751
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)
Thurman Street WWTP
Thurman St
North Wilkesboro NC 28659
Entry Time/Date
10:00AM 20/01/08
Permit Effective Date
15/07/01
Exit Time/Date
12:00PM 20/01/08
Permit Expiration Date
20/06/30
Name(s) of Onsite Representative(s)/Titles(s)/Phone and Fax Number(s)
///
Scotty Dale Perry/ORC/336-838-5001/
Other Facility Data
Name, Address of Responsible Official/Title/Phone and Fax Number
Contacted
Scotty Dale Perry, //336-667-7129/
No
Section C: Areas Evaluated During Inspection (Check only those areas evaluated)
Permit Flow Measurement Operations & Maintenar Records/Reports
Self -Monitoring Progran Sludge Handling Dispos Facility Site Review Effluent/Receiving Wate
Laboratory
Section D: Summary of Finding/Comments (Attach additional sheets of narrative and checklists as necessary)
(See attachment summary)
Name(s) and Signature(s) of Inspector(s) Agency/Office/Phone and Fax Numbers Date
Kelli A Park DWR/WSRO WQ/336-776-9689/
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
NC0020761 111 121 20/01/08
117
Inspection Type
18 [j
(Cont.)
1
Section D: Summary of Finding/Comments (Attach additional sheets of narrative and checklists as necessary)
On January 8, 2020, Kelli Park, of this office, met with Scott Perry, Operator in Responsible Charge,
and Justin Shell, Backup Operator in Responsible Charge, to perform a Compliance Evaluation
Inspection at the Thurman Street wastewater treatment plant. This type of inspection consists of two
basic parts: an in -office file review and an on -site inspection of the treatment facility. The attached EPA
inspection form details the areas that were evaluated during this inspection.
The inspection of the facility was satisfactory. If you have any questions regarding the inspection or
this report, please contact Kelli Park or me at [phone] or by email at [e-mail] or
[e-mail].
Page# 2

Permit: NC0020761
Inspection Date: 01/08/2020
Owner - Facility: Thurman Street VVVVTP
Inspection Type: Compliance Evaluation
Operations & Maintenance
Is the plant generally clean with acceptable housekeeping?
Does the facility analyze process control parameters, for ex: MLSS, MCRT, Settleable
Solids, pH, DO, Sludge Judge, and other that are applicable?
Comment:
Permit
(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?
Is access to the plant site restricted to the general public?
Is the inspector granted access to all areas for inspection?
Yes No NA NE
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Comment: The permit expires in June 2020 and a permit renewal was submitted in November of 2019.
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 operatc
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?
Yes No NA NE
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Page# 3

Permit: NC0020761
Inspection Date: 01/08/2020
Owner - Facility: Thurman Street W\NTP
Inspection Type: Compliance Evaluation
Record Keeping
Facility has copy of previous year's Annual Report on file for review?
Comment: ORC and BORC are a grade 4
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: Calibrated on 3/12/19
Influent Sampling
# Is composite sampling flow proportional?
Is sample collected above side streams?
Is proper volume collected?
Is the tubing clean?
# Is proper temperature set for sample storage (kept at less than or equal to 6.0 degrees
Celsius)?
Is sampling performed according to the permit?
Comment: Sampler pulls 125-130 ml per every 14,000 gallons
Last calibrated on 1/6/2020
Bar Screens
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: Debris go to landfill
Grit Removal
Type of grit removal
a.Manual
Yes No NA NE
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Yes No NA NE
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Yes No NA NE
Page# 4

Permit: NC0020761
Inspection Date: 01/08/2020
Owner - Facility: Thurman Street VVVVTP
Inspection Type: Compliance Evaluation
Grit Removal Yes No NA NE
b.Mechanical
Is the grit free of excessive organic matter?
Is the grit free of excessive odor?
# Is disposal of grit in compliance?
Comment: Grit goes to landfill
Primary 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 sludge blanket level acceptable?
Is the sludge blanket level acceptable? (Approximately'/4 of the sidewall depth)
Comment:
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Aeration Basins Yes No NA NE
Mode of operation Ext. Air
Type of aeration system Surface
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: DO reported to be around 2mg/L
Four surface aerators in each aeration basin (2). to maintain a proper DO level the surface
aerators are rotated where one of them is on each day (per basin) and the rest are off.
Page# 5

Permit: NC0020761
Inspection Date: 01/08/2020
Owner - Facility: Thurman Street VVVVTP
Inspection Type: Compliance Evaluation
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)
Yes No NA NE
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Comment: There are 4 secondary clarifiers. The sludge blanket was 2-3ft deep in each of them. The
sludge depth is checked and recorded daily.
Disinfection - UV
Are extra UV bulbs available on site?
Are UV bulbs clean?
Is UV intensity adequate?
Is transmittance at or above designed level?
Is there a backup system on site?
Is effluent clear and free of solids?
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: Calibrated on 3/12/19
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?
Yes No NA NE
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Page# 6

Permit: NC0020761
Inspection Date: 01/08/2020
Owner - Facility: Thurman Street VVVVTP
Inspection Type: Compliance Evaluation
Effluent Pipe
Comment: Effluent was clear the day of inspection
Effluent Sampling
Is composite sampling flow proportional?
Is sample collected below all treatment units?
Is proper volume collected?
Is the tubing clean?
# Is proper temperature set for sample storage (kept at less than or equal to 6.0 degrees
Celsius)?
Is the facility sampling performed as required by the permit (frequency, sampling type
representative)?
Comment: Sampler pulls 125-130 ml per every 14,000 gallons
Last calibrated on 1/6/2020
Yes No NA NE
Yes No NA NE
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Laboratory Yes No NA NE
Are field parameters performed by certified personnel or 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: Lab certification number 492
Silver, toxicity, nitrogen. and phosphorus are analyzed by Meritech
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?
Yes No NA NE
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Page# 7

Permit: NC0020761
Inspection Date: 01/08/2020
Owner - Facility: Thurman Street VVVVTP
Inspection Type: Compliance Evaluation
Standby Power Yes No NA NE
Comment: The generator is tested every Wednesday
Aerobic Digester
Is the capacity adequate?
Is the mixing adequate?
Is the site free of excessive foaming in the tank?
# Is the odor acceptable?
# Is tankage available for properly waste sludge?
Comment: Dennis Key has the sludge permit WQ0002040
Southern Soil Builders hauls the sludge.
Drying Beds
Is there adequate drying bed space?
Is the sludge distribution on drying beds appropriate?
Are the drying beds free of vegetation?
# Is the site free of dry sludge remaining in beds?
Is the site free of stockpiled sludge?
Is the filtrate from sludge drying beds returned to the front of the plant?
# Is the sludge disposed of through county landfill?
# Is the sludge land applied?
(Vacuum filters) Is polymer mixing adequate?
Comment: Drying beds are no longer used for sludge handling.
Yes No NA NE
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Sometimes the septic hauler will use part of one of the drying beds to dry out oil and grease.
When this occurs the hauler places it within a large containment bag that rests in one of the
beds.
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