NC0085359_Fact Sheet_20210528

Fact Sheet
NPDES Permit No. NC0085359
Permit Writer/Email Contact Nick Coco, [e-mail]:
Date: November 18, 2020
Division/Branch: NC Division of Water Resources/NPDES Municipal Permitting Unit
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:
Union County Public Works/Twelve Mile Creek Water Reclamation
Facility (WRF)
Applicant Address:
4600 Goldmine Road, Monroe, NC 28112
Facility Address:
8299 Kensington Drive, Waxhaw, NC 28173
Permitted Flow:
7.5 MGD with expansion tiers 9.0 MGD and 12.0 MGD
Facility Type/Waste:
MAJOR Municipal; 100% domestic
Facility Class:
Grade IV Biological Water Pollution Control System
Treatment Units:
Mechanical Bar Screens, Influent pump station with stand-by generator,
Vortex grit tanks, Carbon odor control facility, Biological Nutrient
Removal (BNR) Distribution Box, Four (4) BNR basins with anaerobic,
anoxic and aerobic zones, Blower building with standby generator,
MLSS distribution box, Sodium Aluminate storage and feed facilities
for chemical phosphorous trim, Four (4) final clarifiers, Three (3) disc
filters, One (1) UV disinfection facility, Cascade post aeration,
Thickening/Dewatering facility [Two (2) gravity belt thickeners and
two (2) belt filter presses], Four aerobic digesters with jet aeration , 2-
stage wet scrubber odor control facility, Main plant standby generator
Pretreatment Program (Y/N)
N; LTMP in development
County:
Union
Region
Mooresville
Page 1 of 13

Briefly describe the proposed permitting action and facility background: Union County Public Works
has applied for an NPDES permit renewal at 6.0 MGD for the Twelve Mile Creek WRF. The Permittee
requested a name/ownership change to update the facility name from Twelve Mile Creek WWTP to
Twelve Mile Creek WWTP on November 23, 2020. This facility serves a population of 70,608 residents.
Treated domestic wastewater is discharged into Twelve Mile Creek, a class C water in the Catawba River
Basin. The facility has a primary Outfall 001.
The Division received an Engineer's Certification, indicating completion of construction work authorized
under Authorization to Construct Permit 085359A07 in February 2020. The completion of this approved
construction results in an increase in design and permitted capacity to 7.5 MGD, per the existing permit.
While the received renewal application indicated renewal at 6.0 MGD, the 6.0 MGD flow tier has been
removed from the permit, and the effective permitted flow is 7.5 MGD.
2. Receiving Waterbodv Information:
Receiving Waterbody Information
Outfalls/Receiving Stream(s):
Outfall 001 - Twelve Mile Creek
Stream Index:
11-138
Stream Classification:
C
Drainage Area (mi2):
76.8
Summer 7Q10 (cfs)
0.1
Winter 7Q10 (cfs):
1.5
30Q2 (cfs):
--
Average Flow (cfs):
72.7
IWC (% effluent):
99
303(d) listed/parameter:
Yes, Listed for Fish Community and Turbidity in 2018 list
Subject to TMDL/parameter:
Yes- State wide Mercury TMDL implementation.
Subbasin/HUC:
03-08-38/03050103
USGS Topo Quad:
H15NE Catawba, NC
3. Effluent Data Summary
Effluent data for Outfall 001 is summarized below for the period of September 2016 through September
2020.
Table 1. Effluent Data Summary Outfall 001
Parameter
Units
Average
Max
Min
Permit Limit
Flow
MGD
4.1
11.919
2.58
MA 7.5
BOD (summer)
mg/1
2.8
15.2
< 2
WA 7.5
MA 5.0
BOD (winter)
mg/1
2.6
43.3
< 2
WA 15.0
MA 10.0
TSS
mg/1
3.4
.'.
2.5
WA 45.0
MA 30.0
NH3N (summer)
mg/1
0.2
".. ".
0.1
WA 3.0
MA 1.0
NH3N (winter)
mg/1
0.2
7
0.1
WA 5.7
MA 1.9
DO
mg/1
8.9
10.2
7.5
DA > 6 mg/1
Page 2 of 13

Fecal coliform
#/100 ml
(geo mean)
9300
< 1
(geometric)
WA 400
MA 200
Temperature
° C
20.8
27.1
13.2
pH
SU
7.2
7.8
6.2
6.0<pH<9.0
TN
mg/1
10.6
16.8
2.5
TP
lbs/d
6.4
36.12
< 1
MA 41.7
TP
lbs/d
9
19.75
2.59
12-month Average
20.85
MA -Monthly Average_ WA -Weekly Average_ DM -Daily Maximum_ DA-Daily Average_ OA-
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 dissolved oxygen and temperature
Upstream at least 50 feet of the outfall and downstream of the outfall one quarter mile, before confluence
with the first tributary at location D1 and at NCSR 1301 at location D2. Data from September 2016
through September 2020 were observed. The data has been summarized in Table 2 below.
Table 2. Instream Data Summary
Parameter
Units
Upstream
Downstream 1
Downstream 2
Average
Max
Min
Average
Max
Min
Average
Max
Min
DO
mg/1
7.6
14.5
3.9
7.7
15.7
5
7.3
11.9
4.5
Temperature
° C
19.4
27.3
2.2
20.4
28.7
5.8
20.1
27.3
5.9
Students t-tests were run at a 95% confidence interval to analyze relationships between instream
samples. A statistically significant difference is determined when the t-test p-value result is < 0.05
The downstream temperature did not exceed 29 degrees Celsius [per 15A NCAC 02B .0211 (18)] at
either location. The temperature differential between upstream and downstream temperature at location
D1 was greater than 2.8 degrees Celsius on 27 occasions during the period reviewed. The temperature
differential between upstream and downstream temperature at location D2 was greater than 2.8 degrees
Celsius on 21 occasions during the period reviewed. It was concluded that a statistically significant
difference between upstream and downstream temperature exists at downstream location 1. It was
concluded that no statistically significant difference between upstream and downstream temperature
exists at downstream location 2.
Downstream DO did not drop below 5 mg/L [per 15A NCAC 02B .0211 (6)] at location D1 during the
period reviewed. Downstream DO dropped below 5 mg/L on 3 occasions at location D2 during the period
reviewed. It was concluded that no significant difference between upstream and downstream DO exists at
either location.
Page 3 of 13

Union County Public Works has requested in their 2019 NPDES permit renewal application that the
Division remove instream monitoring requirements. Instream monitoring has been in the permit since
1996, given the size of the discharge, the low flow nature of the stream, as well as the need to quantify the
impact as the facility encroaches upon future expansions. Union County conducted an intensive DO
survey during Summer 2009 to evaluate instream DO trends. This data indicates that low DO conditions
are much more prevalent in the upstream stations in Twelve Mile Creek and its tributaries. A primary
conclusion of the County 2009 Summer D.O. study was that during low flow conditions, debris dams and
other obstructions in several locations can slow stream velocity, thus decreasing reaeration rates.
However, from the discharge point, Twelve Mile Creek flows for approximately 2 miles prior to crossing
the NC/SC State line, and ultimately discharges into the Catawba River approximately 15 miles below the
outfall. Continued instream sampling will help to confirm the modeling predictions determined based
upon the WRF's flow expansions. Based on analysis of the instream data from review period, tracking
one of the downstream sites would provide the Division with sufficient data from which to draw
conclusions. As such, instream monitoring has been maintained upstream and at downstream
location D2 but has been removed at downstream location D1.
North Carolina's Natural Characteristics Rule. Instream data for Twelve Mile Creek indicates that DO
levels may on occasion fall below the State water quality standard of 5 mg/1, both above and below the
discharge. State regulation (15A NCAC 2B.0205, Natural Characteristics Outside Standard Limits)
provides that water quality standards will not be considered violated when values outside the normal
range are caused by natural conditions. For wastewater discharges to such waters, the discharger will not
be considered a contributor to substandard conditions provided maximum treatment in compliance with
permit requirements is maintained and therefore meeting the water quality standard is beyond the
discharger's control. As previously stated, instream data and water quality modeling results indicate that
Twelve Mile Creek is naturally low in DO on occasions.
Is this facility a member of a Monitoring Coalition with waived instream monitoring (Y/N): N
Name of Monitoring Coalition: NA
5. Compliance Summary
Summarize the compliance record with permit effluent limits (past 5 years): The facility reported one
fecal coliform weekly average limit violation resulting in enforcement in 2018 and in 2019.
Summarize the compliance record with aquatic toxicity test limits and any second species test results
(past 5 years): The facility passed 18 of 18 quarterly chronic toxicity tests as well as 5 of 5 second species
toxicity tests from February 2016 to May 2020.
Summarize the results from the most recent compliance inspection: The last facility inspection conducted
in October 2020 reported that the facility was in compliance with NPDES permit NC0085359.
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).
Page 4 of 13

If applicable, describe any other dilution factors considered (e.g., based on CORMIX model results): NA
If applicable, describe any mixing zones established in accordance with 15A NCAC 2B. 0204(b): NA
Oxygen -Consuming Waste Limitations
Limitations for oxygen -consuming waste (e.g., BOD) are generally based on water quality modeling to
ensure protection of the instream dissolved oxygen (DO) water quality standard. Secondary TBEL limits
(e.g., BOD= 30 mg/1 for Municipals) may be appropriate if deemed more stringent based on dilution and
model results.
If permit limits are more stringent than TBELs, describe how limits were developed: The existing
limitations for BOD were placed in the permit upon expansion request in 2014 and are based on the
results of a QUAL2E model. Modeling of predicted instream dissolved oxygen (DO) levels using the
Division's Streeter -Phelps -based model were limited in application for Twelve Mile Creek. Therefore,
modeling efforts based on a more representative QUAL2E model to evaluate assimilative capacity were
conducted by Tetra Tech and are presented in two Tetra Tech reports: (a) Scoping Level Assessment of
Assimilative Capacity in Twelve Mile Creek Below the Union County WRF (April 2010), and (b)
QUAL2 Model Update for Twelve Mile Creek below the Union County WRF (February 2012). The
scoping level QUAL2 model results suggested that instream DO concentrations would be expected to
increase well above natural background conditions as a result of increased flow velocity with resultant
increase in reaeration, thus there is additional assimilative capacity for expanded flow. Following this
scoping level assessment, additional instream data collection efforts were undertaken to help with model
refinement. The Updated QUAL2E stream water quality model incorporated additional downstream
survey information, verification of model assumptions, and model recalibration. The updated modeling
results validated the primary conclusion of the scoping level QUAL2E analysis- that there is additional
assimilative capacity available and the wastewater discharge is not predicted to negatively impact
instream DO levels below the discharge. The model scenario results indicate that an increased
wastewater discharge (i.e., up to 12 MGD) would raise the DO levels throughout the pooled sections; in
contrast, complete removal of the discharge was predicted to decrease DO levels in pooled zones by more
than 1 mg/1. Since the discharge is immediately upstream of South Carolina waters, per the request of SC
Department of Health & Environmental Control (DHEC), Tetra Tech refined the QUAL2E model further
(specifically adjusting SOD rates), and evaluated the proposed 12 MGD discharge to Twelve Mile Creek
for compliance with South Carolina's water quality standards, specifically the 0.1 mg/1 DO Deficit Rule
(SC Regulation 61-68, Water Classifications and Standards, Section D). The 0.1 Rule requires that
waterbodies with naturally low DO shall not be cumulatively lowered more than 0.1 mg/1 for DO (Daily
Average) due to point sources or other activities during Summer period (defined as March through
October in SC). SC DHEC (Heather Rizzuti, Wasteload Allocation Section ,July 6, 2012) concluded that
the refined QUAL2E model for Twelve Mile Creek demonstrates overall compliance with the 0.1 Rule,
and that the expanded permit should maintain the critical Summer period of March -October as specified
in the 0.1 Rule.
The Division received comments from the County on January 29, 2021, requesting that the proposed draft
permit replace the BOD5 limits with CBOD5 limits [See attached for request]. The existing BOD5 limits
were placed in the permit as a result of a 2010-2012 QUAL2E model. After reviewing the model again,
the Division has concluded that carbonaceous BOD was used and the conclusion of the model
(implemented in the permit) was for carbonaceous BOD. As such, the Division has decided to grant the
request for CBOD5 limits to replace the existing BOD5 limits. This decision has been proposed and agreed
to by the State of South Carolina (SCDHEC) on February 8, 2021.
Page 5 of 13

Ammonia and Total Residual Chlorine Limitations
Limitations for ammonia are based on protection of aquatic life utilizing an ammonia chronic criterion of
1.0 mg/1 (summer) and 1.8 mg/1 (winter). Acute ammonia limits are derived from chronic criteria,
utilizing a multiplication factor of 3 for Municipals and a multiplication factor of 5 for Non -Municipals.
Limitations for Total Residual Chlorine (TRC) are based on the NC water quality standard for protection
of aquatic life (17 ug/1) and capped at 28 ug/1 (acute impacts). Due to analytical issues, all TRC values
reported below 50 ug/1 are considered compliant with their permit limit.
Describe any proposed changes to ammonia and/or TRC limits for this permit renewal: The current
permit does not set a limit or monitoring requirement for TRC since the facility uses UV and does not
have a backup chlorination system. There are no proposed changes for TRC.
The current ammonia limits were upon expansion request in 2014 and are based on the results of a
QUAL2E model [See previous section on BOD limits for more information on the model]. Ammonia -
nitrogen limits have been reviewed in the attached WLA and have been found to be protective. No
changes are proposed at any existing flow tier.
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 September
2016 through September 2020 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: NA
• Monitoring Only. The following parameters will receive a monitor -only requirement since they
did not demonstrate reasonable potential to exceed applicable water quality standards/criteria,
but the maximum predicted concentration was >50% of the allowable concentration: NA
• No Limit or Monitoring: The following parameters will not receive a limit or monitoring, since
they did not demonstrate reasonable potential to exceed applicable water quality
standards/criteria and the maximum predicted concentration was <50% of the allowable
concentration: Total Copper, Total Zinc
• POTW Effluent Pollutant Scan Review: Three effluent pollutant scans were evaluated for
additional pollutants of concern. (PPAs from 2016, 2017, 2018 and 2019)
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, RP was shown, but fewer than two exceeded the allowable discharge
concentration: Total Cadmium
Page 6 of 13

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 Chromium, Chlorides, Total Cyanide, Total Lead, Total
Nickel, Total Selenium, Total Silver
The facility has inadvertently reported a value of 13000 ug/L for total cadmium on 9/11/2018 in their
discharge monitoring report. The facility provided the Division with a lab sheet clarifying that this value
reflected calcium sampling on that day, and that total cadmium was not sampled on 9/11/2018.
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.
Site Specific Study Background information:
Union County submitted the site -specific criteria study in September 2003. After an extensive review,
consultation between the County, their engineering consultants and the Division, along with input from
the EPA, site -specific standards for the Twelve Mile Creek were developed. Previously, there was a
significant discussion on the County's exclusion of Cladocerans from the National Dataset (September
2004 meeting). The Division presented information to the County and EPA that determined that
Cladocerans should be included in developing the site -specific criteria. The EPA, East Standard,
Monitoring and TMDL Section, reviewed the data and concurred with the Division (Jan. 2005 letter). The
County submitted revised site -specific criteria that included Cladocerans in March 2005. The criteria were
as follows Copper = 10.2 ug/1, Zinc = 91.6 ug/1. Copper and zinc limits in the previous permits were
based on demonstrated RP to exceed water quality standards in South Carolina. The applicable site -
specific copper/zinc standards were originally developed based on a study by Union County in
conjunction with the State of South Carolina and based on Water Effect Ratio (WER) calculations. The
existing permit limitations are based on a WER study performed in 2005/2006 which determined that a
Cu limitation of 12.9 µg/L and a Zn limitation of 171 µg/L would be sufficient to protect SC water quality
standards. The EPA's 1994 Interim Guidance on the Determination and Use of Water -Effect Ratios for
Metals recommends establishing a permit condition for periodic testing of WERs to verify the site -
specific criteria. The Division has not received an updated WER to confirm the 2005/2006 results. As
such, a special condition has been added to the permit requiring a confirmatory WER be conducted.
Toxicity Testing Limitations
Permit limits and monitoring requirements for Whole Effluent Toxicity (WET) have been established in
accordance with Division guidance (per WET Memo, 8/2/1999). Per WET guidance, all NPDES permits
issued to Major facilities or any facility discharging "complex" wastewater (contains anything other than
domestic waste) will contain appropriate WET limits and monitoring requirements, with several
exceptions. The State has received prior EPA approval to use an Alternative WET Test Procedure in
NPDES permits, using single concentration screening tests, with multiple dilution follow-up upon a test
failure.
Describe proposed toxicity test requirement: The permit requires quarterly chronic toxicity testing at
90% effluent concentration at the 7.5 MGD, 9.0 MGD and 12.0 MGD flow tiers. 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
Page 7 of 13

wasteload allocation for point sources of 37 kg/year (81 lb/year), and is applicable to municipals and
industrial facilities with known mercury discharges. Given the small contribution of mercury from point
sources (-2% of total load), the TMDL emphasizes mercury minimization plans (MMPs) for point source
control. Municipal facilities > 2 MGD and discharging quantifiable levels of mercury (>1 ng/1) will
receive an MMP requirement. Industrials are evaluated on a case -by -case basis, depending if mercury is a
pollutant of concern. Effluent limits may also be added if annual average effluent concentrations exceed
the WQBEL value (based on the NC WQS of 12 ng/1) and/or if any individual value exceeds a TBEL
value of 47 ng/1.
Table 3. Mercury Effluent Data Summary (7.5 MGD)
2016
2017
2018
2019
2020
# of Samples
1
1
1
1
2
Annual Average Conc. ng/L
1.1
0.5
0.89
0.5
0.7
Maximum Conc., ng/L
1.1
0.5
0.89
0.5
0.97
TBEL, ng/L
47
WQBEL, ng/L
12.1
Describe proposed permit actions based on mercury evaluation: Since no annual average mercury
concentration exceeded the WQBEL, and no individual mercury sample exceeded the TBEL, no mercury
limit is required. Since the facility is > 2 MGD in design capacity but did not report multiple (> 1
sample) quantifiable levels of mercury (> 1 ng/L), no mercury minimization plan (MMP) is required. The
MMP requirement has been removed from the permit.
Other TMDL/Nutrient Management Strategy Considerations
If applicable, describe any other TMDLs/Nutrient Management Strategies and their implementation
within this permit:
Total Phosphorus (TP). The permit renewal and the existing permit contain total phosphorus mass -based
limits. The mass loading limits (Monthly Average = 41.7 lbs/day, Annual Average = 20.85 lbs/day) were
capped to ensure no additional TP load, even with expansion to 12.0 MGD. These limits were based on a
Union County /DWQ/SCDHEC Settlement Agreement for the inclusion of phosphorus limits to
dischargers to the main stem of the Catawba (upstream of Lake Wateree), to comply with the SC lake
standard of 0.06 mg/1. At 12 MGD, the TP mass limits equate to a Monthly Average concentration of 0.42
mg/1, and an Annual Average concentration of 0.21 mg/1.
Note: The existing permit required the Permittee to submit a nutrient worksheet with their physical
Discharge Monitoring Reports to track Monthly and 12-Month Mass Averages for Total Phosphorous. As
the Division is moving to accept data electronically through the eDMR system, this physical worksheet
requirement has been removed from the permit. The Permittee shall continue to report Monthly Average
Total Phosphorous and 12-Month Mass Average Loading Total Phosphorous via the Division's eDMR
system.
Other WQBEL Considerations
If applicable, describe any other parameters of concern evaluated for WQBELs: NA
If applicable, describe any special actions (HQW or ORW) this receiving stream and classification shall
comply with in order to protect the designated waterbody: NA
Page 8 of 13

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/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; the facility achieved 85%
overall removal for BOD and TSS. Permiee requested and was granted the replacement of BOD limits
and monitoring with CBOD limits and monitoring as part of this renewal.
IfNO, 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,
Page 9 of 13

Reduced Monitoring Frequencies for Facilities with Superior Compliance (10/22/2012 Memo); 4) Best
Professional Judgement (BPJ). Per US EPA (Interim Guidance, 1996), monitoring requirements are not
considered effluent limitations under Section 402(o) of the Clean Water Act, and therefore anti -
backsliding prohibitions would not be triggered by reductions in monitoring frequencies.
For instream monitoring, refer to Section 4.
In their 2019 renewal application, Union County Public Works has requested continuation of reduced
monitoring frequencies for CBOD5, Total Suspended Solids, NH3-N and Fecal Coliform based on DWR
Guidance Regarding the Reduction of Monitoring Frequencies in NPDES Permits for Exceptionally
Performing Facilities. The last three years of the facility's data for these parameters have been reviewed
in accordance with the criteria outlined in the guidance. 2/week monitoring for CBOD5, Total Suspended
Solids, NH3-N and Fecal Coliform has been maintained. Note: BOD data was used in the assessment, as
the facility requested and granted the replacement of BOD requirements with CBOD requirements as part
of this renewal.
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 7.5 MGD, 9.0 MGD and 12.0 MGD — Each tier
has the same limits
Parameter
Current Permit
Proposed Change
Basis for Condition/Change
Flow
MA 6.0 MGD with
MA 7.5 MGD with
15A NCAC 2B .0505, ATC
expansion flow
expansion flow tiers 9.0
Engineer's Certification received
tiers 7.5 MGD, 9.0
MGD and 12.0 MGD
for expansion to 7.5 MGD tier.
MGD and 12.0
MGD
BODS
Summer (March —
Replaced by CBOD5.
WQBEL. 2014 QUAL2E model.
October):
Summer (March —
15A NCAC 2B; DWR Guidance
MA 5.0 mg/1
October):
Regarding the Reduction of
WA 7.5 mg/1
MA 5.0 mg/1
Monitoring Frequencies in NPDES
Winter:
WA 7.5 mg/1
Permits for Exceptionally
MA 10.0 mg/1
Winter:
Performing Facilities; Seasonal
WA 15.0 mg/1
MA 10.0 mg/1
range due to SC 0.1 mg/L D.O.
2/week monitoring
WA 15.0 mg/1
2/week monitoring
Rule. 2021 Permittee request for
CBOD5 limitations
Page 10 of 13

NH3-N
Summer (March -
October):
MA 1.0 mg/1
WA 3.0 mg/1
Winter:
MA 1.9 mg/1
WA 5.7 mg/1
2/week monitoring
No change
WQBEL. 2014 QUAL2E model.
15A NCAC 2B; DWR Guidance
Regarding the Reduction of
Monitoring Frequencies in NPDES
Permits for Exceptionally
Performing Facilities; Seasonal
range due to SC 0.1 mg/L D.O.
Rule.
TSS
MA 30 mg/1
WA 45 mg/1
2/week monitoring
No change
TBEL. Secondary treatment
standards/40 CFR 133 / 15A
NCAC 2B .0406; DWR Guidance
Regarding the Reduction of
Monitoring Frequencies in NPDES
Permits for Exceptionally
Performing Facilities
Fecal coliform
MA 200 /100m1
WA 400 /100m1
2/week monitoring
No change
WQBEL. State WQ standard, 15A
NCAC 2B; DWR Guidance
Regarding the Reduction of
Monitoring Frequencies in NPDES
Permits for Exceptionally
Performing Facilities
DO
DA > 6 mg/1
No change
WQBEL. Based on results of the
Union County instream DO study
conducted during Summer 2009 as
well as the 2014 QUAL2E scoping
level assessment.
Temperature
Monitor and
Report Daily
No change
Surface Water Monitoring, 15A
NCAC 2B. 0500
pH
6 - 9 SU
No change
WQBEL. State WQ standard, 15A
NCAC 2B
Total Nitrogen
Monitor and
Report Monthly
No change
Surface Monitoring Requirements
15A NCAC 02B .0508
Total Phosphorous
MA 41.7 lb/d
12-month Average
20.85 lb/d
Monitor and
Report Monthly
No change
WQBEL. Union County
/DWQ/SCDHEC Settlement
Agreement for the inclusion of
phosphorus limits to dischargers to
the main stem of the Catawba
(upstream of Lake Wateree), to
comply with the SC lake standard
of 0.06 mg/1
Instream Monitoring
Upstream and at 2
downstream
locations
Upstream and at 1
downstream location
BPJ. Instream monitoring data
review
Chronic Toxicity
Chronic limit,
90% effluent
No change
WQBEL. No toxics in toxic
amounts. 15A NCAC 2B
Effluent Pollutant Scan
Three times per
permit cycle
No change; conducted
in 2022, 2023, 2024
40 CFR 122
Page 11 of 13

Mercury Minimization
Plan (MMP)
MMP Special
Condition
Remove special
condition
For POTW > 2 MGD and no more
than one sample (>1 ng/1), no
MMP required
Confirmatory WER
study Condition
No requirement
Special Condition A.(8.)
Water Effect Ratio
Confirmation
For verification of site -specific
criteria developed in 2005/2006;
1994 Interim Guidance on the
Determination and Use of Water -
Effect Ratios for Metals
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, AA — Annual Average
13. Public Notice Schedule:
Permit to Public Notice: November 24, 2020 and February 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 Union County Public Works, EPA Region IV, South Carolina DHEC, and
the Division's Mooresville Regional Office, Aquatic Toxicology Branch and Operator Certification
Program for review. The Division received comments from Union County Public Works on December 21,
2020 regarding updating the supplement to cover's facility components list and correcting various typos.
One comment was made related to the draft permit incorrectly listing monitoring frequencies for total
phosphorous and total nitrogen as "weekly" instead of "monthly." The fact sheet to the permit correctly
noted monthly monitoring in accordance with 15A NCAC 02B .0508 and the existing permit had monthly
monitoring frequencies for the two parameters. As such, this inconsistency is treated as a typographical
error and has been considered to be a minor modification not resulting in additional public comment. The
full list of Union County's comments has been attached to this fact sheet, as well as the final cover letter.
No comments were received from any of the other parties.
The County submitted comments to the Division on January 29, 2021 requesting replacement of BOD5
limits with CBOD5 limits [See Section 6. of this fact sheet for a more in-depth summary] This request
has been granted and results in the need for additional public notice. As such, a second draft with these
proposed changes was submitted for public comment on February 16, 2021.
Were there any changes made since the November 24, 2020 Draft Permit was public noticed (Yes/No):
YES
If Yes, list changes and their basis below:
Page 12 of 13

• A typographical error regarding the monitoring frequencies for total phosphorous and total
nitrogen in Sections A.(1.) through A.(3.) has been corrected.
• A typographical error has been corrected in the header to Section A.(3.).
• Special Condition A.(8.) has been corrected to reference total zinc instead of total silver.
• The facility components list in the supplement to cover has been updated for accuracy.
• Per request by the County, CBOD5 limits have replaced BOD5 limits [See A.(1.) — A.(3.)].
A second draft permit was submitted for public comment on February 16, 2021. The draft was submitted
to the Union County Public Works, EPA Region IV, South Carolina DHEC, and the Division's
Mooresville Regional Office, Aquatic Toxicology Branch and Operator Certification Program for review.
No comments were received from any party.
Were there any changes made since the February 16, 2021 Draft Permit was public noticed (Yes/No): No
If Yes, list changes and their basis below: NA
15. Fact Sheet Attachments (if applicable):
• County Comments and Division responses
• RPA Spreadsheet Summary
• BOD and TSS Removal
• Monitoring Reduction Frequency Spreadsheet
• Dissolved Metals Implementation/Freshwater
• Waste Load Allocation Spreadsheet
• Mercury TMDL Spreadsheet
• Toxicity Summary
• Instream Monitoring Summary
• Renewal Application Addendum
• Name/Ownership Change Request
Page 13 of 13

AFFP
Public Notice North Carolina
Affidavit of Publication
STATE OF NORTH
CAROLINA }
COUNTY OF }
SS
Kimberly Cook, being duly sworn, says:
That she is the billing clerk of the The Enquirer Journal, a
daily newspaper of general circulation, printed and
published in Monroe, County, North Carolina; that the
publication, a copy of which is attached hereto, was
published in the said newspaper on the following dates:
February 16, 2021
That said newspaper was regularly issued and circulated
on those dates.
SIGNED:
the billing c14<
Subscribed to and sworn to me this 16th day of February
2021.
Barbara M Daniels, Notary, Guilford County, County,
North Carolina
My commission expires: February 01, 2022
i1}Ii 111171111„,',
30146484 30926181
Wren Thedford
Division Of Water Resources
1617 Mail Service Center
Raleigh, NC 27699
TA,c`;(0
1
:GG AO$LlC 'U
131 .�I'"%,„S' j c.0- -
Public Notice
North Carolina
Environmental Management
Commission/NPDES Unit
1617 Mail Service Center
Raleigh, NC 27699-1617
Notice of Intent to Issue a
NPDES Wastewater Permit
NC0085359 Twelve Mill
Creek WWTP
The North Carolina Environ-
mental Management Commis-
sion proposes to issue a NP-
DES wastewater discharge
permit to the person(s) listed
below. Written comments re-
garding the proposed permit
will be accepted until 30 days
after the publish date of this
notice. The Director of the NC
Division of Water Resources
(DWR) may hold a public
hearing should there be a sig-
nificant degree of public in-
terest. Please mail comments
and/or information requests to
DWR at the above address,
interested persons may visit
the DWR at 512 N. Salisbury
Street, Raleigh, NC 27604 to
review information on file. Ad-
ditional information on NP-
DES permits and this notice
may be found on our website:
http://deq. nc.gov/about/divi-
sio n s/waler-resources/water-
resources-permits/
wastewater-branch/nodes-
wastewater/public-notices,or
by calling [phone],
Union County Public Works
[4600 Goldmine Road, Mon-
roe, NC 28112] has reques-
ted renewal of NPDES permit
NC0085359 for its Twelve Mile
Creek Water Reclamation Fa-
cility, located in Union County.
This permitted facility dis-
charges treated municipal
wastewater to Twelve Mile
Creek, a class C water in the
Catawba River Basin. Cur-
rently CBOD5, NH3, dis-
solved oxygen, fecal coliform,
pH, and total phosphorus are
water quality limited. This dis-
charge may affect future alloc-
ations in this segment of
Twelve Mile Greek.
Feb. 16, 2021

Union County
EST. 1842
January 29, 2021
Public Works
4600 Goldmine Rd
Monroe NC 28110
T. 704-289-1434
Iwww.unioncountync.gov
Mr. Mike Montebello
Water Quality Permitting Section — NPDES
Division of Water Resources
North Carolina Department of Environmental Quality
1617 Mail Service Center
Raleigh, NC, 27699-1617
RE: Union County Public Works
Twelve Mile Creek Water Reclamation Facility
Modification Request to NPDES Permit No. NC0085359
Dear Mr. Montebello,
Union County Public Works Department (UCPW) received the Draft National Pollutant Discharge
Elimination System (NPDES) permit for our Twelve Mile Creek Water Reclamation Facility (WRF) on
December 7, 2020. We provided comments on the draft permit on December 21, 2021, which is within
the 30-day comment window. We understand that the draft permit has been released for public notice, but
the final permit has not yet been issued.
We have recently completed an in-depth review of our historical plant data for plant optimization. In
reviewing our historical data, we noted that the Twelve Mile Creek WRF has demonstrated slight
increases in the effluent five-day biochemical oxygen demand (BOD5) concentration in the past several
years. The Twelve Mile Creek WRF maintains compliance with effluent permit limits; however, we
suspect a nitrogen interference in the effluent BOD results.
BOD5 measures the oxygen consumed to biologically degrade organic matter, oxidize inorganic
chemicals, and oxidize reduced forms of nitrogen (e.g., ammonia). The portion of the measured BOD5
associated with the organic oxygen demand is known as carbonaceous BOD5 (cBOD5). The portion of the
measured BOD5 associated with oxidizing nitrogen is known as the nitrogenous BOD5 (nBOD5).
Many plants with ammonia and/or total Kjeldahl nitrogen (TKN) limits have a cBOD5 limit instead of
BOD5. A cBOD5 measurement prevents ammonia from influencing the analysis. A concentration of
1 mg/L ammonia exerting a 4.6 mg/L oxygen demand results in an elevated BOD5 concentration. A
nitrification inhibitor is often added to suppress nitrification activity, resulting in more accurate
measurement of the eBOD5. Standard Methods for the Examination of Water and Wastewater (2017)
recommends that a nitrification inhibitor (as directed in Standard Method 5210 B.5e) be used for

secondary effluent measurement to provide a more accurate estimate of cBOD5.
We respectfully request a change to our BOD5 effluent limit of 5 mg/L to a cBOD5 effluent limit. We
believe that cBODs effluent will more accurately portray the effluent quality of our facility. A cBOD5
effluent limit will also avoid double -counting the impacts of ammonia on the receiving stream.
If you have any questions, please contact me at [phone] or [e-mail].
Sincerely,
Lit,4
Andrew Neff, PE
Water and Wastewater Division Director
cc: Bart Farmer, Union County Public Works, Water Reclamation Facilities Superintendent
Jonathan Jordan, Union County Public Works, Supervisor Twelve Mile Creek WRF
Mary Sadler, PE, Hazen and Sawyer
Jim Struve, PE, Hazen and Sawyer
Page 2

Monday, February 8, 2021 at 16:05:21 Eastern Standard Time
Subject: Re: [External] Re: NC0085359 Twelve Mile Creek WWTP Permit Limit Modification
Date: Monday, February 8, 2021 at 3:11:47 PM Eastern Standard Time
From: Rizzuti, Heather
To: Coco, Nick A
CC: Cantrell, Wade, Montebello, Michael J
Attachments: image001.png, image002.png, image003.png, image004.png
CAUTION: External email. Do not click links or open attachments unless you verify. Send all suspicious email as an attachment
to Report Spam.
Nick Coco,
Yes, for the NC0085359 permit reissuance, SCDHEC is in agreement with NC DWR about changing the
parameter from BOD5 to CBOD5 without changing the limits themselves. SCDHEC does not oppose
changing the BOD5 limits to CBOD5 limits with the same values. To be specific, for all the effluent
flows on the referenced draft permit, the current summer and winter monthly average BOD5 limits of
5 mg/L and 10 mg/L, respectively, can be changed to summer and winter monthly average CBOD5
limits of 5 mg/L and 10 mg/L. The weekly average BOD5 parameter can also be changed to
CBOD5 without changing the limits themselves.
Please let Wade Cantrell and me know if you have any further questions.
Heather Bartley Rizzuti, M.S.
Environmental Health Manager II
S.C. Dept. of Health & Environmental Control
303(d), Modeling & TMDL Section, Bureau of Water
Office: [phone]
Connect: www.scdhec.gov Facebook Twitter
From: Coco, Nick A <[e-mail]>
Sent: Monday, February 8, 2021 1:28 PM
To: Rizzuti, Heather <[e-mail]>
Cc: Cantrell, Wade <[e-mail]>; Montebello, Michael J <[e-mail]>
Subject: Re: [External] Re: NC0085359 Twelve Mile Creek WWTP Permit Limit Modification
***Caution. This is an EXTERNAL email. DO NOT open attachments or click links from unknown senders or unexpected
email.***
Hi Heather,
NC DWR is proposing to change the parameter from BOD5 to CBOD5 without a change to the limits
themselves. After reviewing the 2010-2012 Tetra Tech QuaI2E model, it appears carbonaceous BOD was used
Page 1 of 5

and the conclusion of the model (implemented in the permit) was for carbonaceous BOD. I have attached the
model results for your reference. Do you believe SCDHEC would be in agreement with this conclusion?
Thanks in advance,
Nicholas A. Coco, El
Engineer
NPDES Municipal Permitting Unit
NC DEQ/ Division of Water Resources / Water Quality Permitting
919 707-3609 office
919 707 9000 main office
[e-mail]
St., Raleigh, NC, 27604
enter, Raleigh, NC, 27699-1617
State of Emergency and DWR policy for Covid-19. Thanks for being patient
available to talk by phone or meet via Microsoft Teams**
t : _ Nothin
Email correspondence to and from this address is subject to the
North Carolina Public Records Law and may be disclosed to third parties.
From: "Coco, Nick A" <[e-mail]>
Date: Monday, February 8, 2021 at 12:19 PM
To: "Rizzuti, Heather" <[e-mail]>
Cc: "Cantrell, Wade" <[e-mail]>, "Montebello, Michael J"
<[e-mail]>
Subject: Re: [External] Re: NC0085359 Twelve Mile Creek WWTP Permit Limit Modification
Hi Heather,
NC DWR is proposing to change the parameter from BOD5 to CBOD5 without a change to the limits
themselves. After reviewing the 2010-2012 Tetra Tech QuaI2E model, it appears carbonaceous BOD was used
and tha rnnrliicinn rf tha mnrdal limnIamantard in tha narmitl roue fnr rarhnnaraniic RC f 1 haves attarhard tha
Page 2 of 5

model results and Division correspondences for your reference. Do you believe SCDHEC would be in
agreement with this conclusion?
Sorry that the file is in a ZIP. I got the message kicked back because the PDF was too large.
Thanks in advance,
Nicholas A. Coco, El
Engineer
NPDES Municipal Permitting Unit
NC DEQ/ Division of Water Resources / Water Quality Permitting
919 707-3609 office
919 707 9000 main office
nick.coco a(�ncdenr.gov
Physical Address: 512 North Salisbury St., Raleigh, NC, 27604
Mailing Address: 1617 Mail Service Center, Raleigh, NC, 27699-1617
I'm working at home due to the State of Emergency and DWR policy for Covid-19. Thanks for being patient
as we try to stay safe.
**Email is preferred but we are available to talk by phone or meet via Microsoft Teams**
Email correspondence to and from this address is subject to the
North Carolina Public Records Law and may be disclosed to third parties.
From: "Coco, Nick A" <[e-mail]>
Date: Monday, February 8, 2021 at 12:13 PM
To: "Rizzuti, Heather" <[e-mail]>
Cc: "Cantrell, Wade" <[e-mail]>, "Montebello, Michael J"
<[e-mail]>
Subject: Re: [External] Re: NC0085359 Twelve Mile Creek WWTP Permit Limit Modification
Hi E-laathar
Page 3 of 5

NC DWR is proposing to change the parameter from BOD5 to CBOD5 without a change to the limits
themselves. After reviewing the 2010-2012 Tetra Tech QuaI2E model, it appears carbonaceous BOD was used
and the conclusion of the model (implemented in the permit) was for carbonaceous BOD. I have attached the
model results and Division correspondences for your reference. Do you believe SCDHEC would be in
agreement with this conclusion?
Thanks in advance,
Nicholas A. Coco, El
Engineer
NPDES Municipal Permitting Unit
NC DEQ/ Division of Water Resources / Water Quality Permitting
919 707-3609 office
919 707 9000 main office
[e-mail]
Physical Address: 512 North Salisbury St., Raleigh, NC, 27604
Mailing Address: 1617 Mail Service Center, Raleigh, NC, 27699-1617
I'm working at home due to the State of Emergency and DWR policy for Covid-19. Thanks for being patient
as we try to stay safe.
**Email is preferred but we are available to talk by phone or meet via Microsoft Teams**
Email correspondence to and from this address is subject to the
North Carolina Public Records Law and may be disclosed to third parties.
From: "Rizzuti, Heather" <[e-mail]>
Date: Tuesday, February 2, 2021 at 2:29 PM
To: "Coco, Nick A" <[e-mail]>
Cc: "Cantrell, Wade" <[e-mail]>, "Montebello, Michael J"
<[e-mail]>
Subject: [External] Re: NC0085359 Twelve Mile Creek WWTP Permit Limit Modification
Page 4 of 5

Nick Coco,
We at SCDHEC have a couple of questions before we give you an answer. Is NC DWR proposing to
change the monthly average BOD5 limits to CBOD5 and keep the same concentration value? To be
specific, is NC DWR proposing to change the current summer and winter monthly average BOD5 limits
of 5 mg/L and 10 mg/L to CBOD5 limits of 5 mg/L and 10 mg/L, or change the CBOD5 values? If the
values are proposed to be changed, then what values?
Heather Bartley Rizzuti, M.S.
Environmental Health Manager II
S.C. Dept. of Health & Environmental Control
303(d), Modeling & TMDL Section, Bureau of Water
Office: [phone]
Connect: www.scdhec.gov Facebook Twitter
0❑
From: Coco, Nick A <[e-mail]>
Sent: Tuesday, February 2, 2021 9:45 AM
To: Rizzuti, Heather <[e-mail]>
Cc: Cantrell, Wade <[e-mail]>; Montebello, Michael J <[e-mail]>
Subject: NC0085359 Twelve Mile Creek WWTP Permit Limit Modification
***Caution. This is an EXTERNAL email. DO NOT open attachments or click links from unknown senders or unexpected
email.***
Hi Heather,
I hope all is well.
I am currently working on the NPDES permit renewal for Union County'sTwelve Mile Creek WWTP, permitted
under NPDES permit NC0085359. A draft permit for this facility has already gone out for public notice and NC
DWR has received a comment from the County requesting that the BOD limit in the permit be changed to
CBOD. Currently, the Twelve Mile Creek WWTP has summer and winter monthly average limits of 5 mg/L and
10 mg/L, respectively. These limits are a result of a 2012 QUAL2E model conducted by Tetra Tech. Since the
discharge crosses the state line into SC, SCDHEC had reviewed the 2012 model, and Tetra Tech refined the
QUAL2E model further (specifically adjusting SOD rates) based on your comments, and evaluated the
proposed 12 MGD discharge to Twelve Mile Creek for compliance with South Carolina's water quality
standards, specifically the 0.1 mg/I DO Deficit Rule. NC DWR does not oppose changing the BOD limits to be
CBOD limits, but we wanted to see if SC DHEC was in agreement. Additionally, we wanted to make sure that
the BOD limits set from the model were equivalent to what the CBOD limits would be, or if the model was
conducted with more specificity, and CBOD limits need to be calculated based on a CBOD/BOD ratio.
Page 5 of 5

Thanks in advance for your time.
Best,
Nicholas A. Coco, El
Engineer
NPDES Municipal Permitting Unit
NC DEQ/ Division of Water Resources / Water Quality Permitting
919 707-3609 office
919 707 9000 main office
nick.coco a(�ncdenr.gov
"'--" St., Raleigh, NC, 27604
enter, Raleigh, NC, 27699-1617
State of Emergency and DWR policy for Covid-19. Thanks for being patient
available to talk by phone or meet via Microsoft Teams**
—' Nothin
Email correspondence to and from this address is subject to the
North Carolina Public Records Law and may be disclosed to third parties.
Page 6 of 5

Union County
December 21, 2020
Public Works
4600 Goldmine Rd
Monroe NC 28110
T. 704-289-1434
www.unioncountync.gov
Mr. Mike Montebello
Water Quality Permitting Section —NPDES
Division of Water Resources
North Carolina Department of Environmental Quality
1617 Mail Service Center
Raleigh, NC, 27699-1617
RE: Union County Public Works
Twelve Mile Creek Water Reclamation Facility
NPDES Permit Renewal, Permit No. NC0085359
Dear Mr. Montebello,
Union County Public Works Department (UCPW) received the Draft National Pollutant Discharge
Elimination System (NPDES) permit for our Twelve Mile Creek Water Reclamation Facility (WRF) on
December 7, 2020. We have reviewed our draft permit and wish to provide the following comments to the
Division of Water Resources (DWR).
1. On the supplement to the cover sheet, the description of the facility infrastructure is inaccurate. The
following list of components is an accurate description of the WRF infrastructure:
• Mechanical Bar Screens
• Influent Pump Station with Standby Generator
• Vortex Grit Tanks
• Carbon Odor Control Facility
• Biological Nutrient Removal (BNR) Distribution Box
• Four (4) BNR Basins with anaerobic, anoxic and aerobic zones
• Blower Building with Standby Generator
• MLSS Distribution Box
• Sodium Aluminate Storage and Feed Facilities for Chemical Phosphorus Trim
• Four (4) Final Clarifiers
■ Three (3) Disc Filters
• One (1) UV Disinfection Facility
■ Cascade Post Aeration
• Thickening / Dewatering Facility (two (2) gravity belt thickeners and two (2) belt filter
presses)
• Four (4) Aerobic Digesters with Jet Aeration
• 2-Stage Wet Scrubber Odor Control Facility
• Main Plant Standby Generator
Additionally, please update the treatment unit description in the Fact Sheet table of Basic Facility
Information.

2. Please update the permitted flow in the Fact Sheet table of Basic Facility Information to remove the
6 mgd plant capacity.
3. Revision to Title Header: The title header of A.(3.) should be modified to reflect a design flow of
12 mgd and not 10 mgd. The header should be revised as follows:
EFFLUENT LIMITATIONS AND MONTIORING REQUIREMENTS [12.0 MGD]
4. WER Confirmation Provision Section A.(8): The County conducted a Water Effect Ratio (WER)
study for copper and zinc in 2005/2006. Section A.(8) needs to be updated to change "silver" to zinc."
The Fact Sheet documents that a WER study for copper and zinc was conducted.
5. Effluent Limitations and Monitoring Requirements (A.(1), A.(2), and A.(3)) — Frequency of
monitoring for total nitrogen and phosphorus: The draft permit indicates a change in the frequency of
monitoring for total nitrogen and phosphorus from "monthly" to "weekly" on all three effluent limits
pages. Our current permit requires monthly monitoring for total nitrogen and phosphorus. We believe
that this change is in error, as page 11 of the Fact Sheet does not provide a basis for the increased
monitoring frequency for these two parameters. Please revise the monitoring requirements for
nitrogen and phosphorus from a weekly requirement to a monthly requirement per our current permit.
If you have any questions regarding any of the NPDES permit renewal application materials, please
contact me at [phone] or [e-mail].
Sincerely,
Andrew Neff, PE
Water and Wastewater Division Director
cc:
Bart Farmer, Union County Public Works, Water Reclamation Facilities Superintendent
Jonathan Jordan, Union County Public Works, Supervisor Twelve Mile Creek WRF
Mary Sadler, PE, Hazen and Sawyer
Jim Struve, PE, Hazen and Sawyer
Page 2

Fact Sheet Addendum
The Division received comments from the Union County Public Works on December 21, 2020 and
provides the following responses:
1. The facility components list has been updated in both the supplement to cover sheet and the fact sheet.
2. The reference to the 6.0 MGD flow tier has been removed from the basic facility information table in the fact
sheet, as the tier no longer exists in the permit.
3. The typographical error in the header of Section A.(3.) referencing a 10.0 MGD flow tier instead of a 12.0
MGD flow tier has been corrected.
4. The typographical error in Special Condition A.(8.) referencing silver instead of zinc has been corrected.
5. The typographical error in Sections A.(1.) through A.(3.) referencing weekly monitoring instead of monthly
monitoring for total phosphorous and total nitrogen has been corrected.
The full list of comments received is attached to this document.

AFFP
Public Notice
Affidavit of Publication
STATE OF NORTH
CAROLINA }
COUNTY OF }�,� U�
SS
Kimberly Cook, being duly sworn, says:
That she is the billing clerk of the The Enquirer Journal, a
daily newspaper of general circulation, printed and
published in Monroe, County, North Carolina; that the
publication, a copy of which is attached hereto, was
published in the said newspaper on the following dates:
December 05, 2020
That said newspaper was regularly issued and circulated
on those dates.
SIGNED:
[a,
the billing clerl{
Subscribed to and sworn to me this 5th day of December
2020.
oLG.(.tl/R
Barbara M Daniels, Notary, Guilford County, County,
North Carolina
My commission expires: February 01, 2022
30146484 30920338
Wren Thedford t,,,,nrrr¢e,,,,�'
Division Of Water Resources 131,y , ., M D. ,''
1617 Mail Service Center r='" - •`:(
Raleigh, NC 27699 ,, ;,•�\a-t /�� j, ' �S
e 4
1)UC �\C. ; c2 ..
Public Notice
North Carolina
Environmental Management
CommissionfNPDES Unit
1617 Mail Service Center
Raleigh, NC 27699-1617
Notice of Intent to Issue a
NPDES Wastewater Permit
NC0085359 Twelve Mile
Creek WWTP
The North Carolina Environ-
mental Management Commis-
sion proposes to issue a NP-
DES wastewater discharge
permit to the person(s) listed
below. Written comments re-
garding the proposed permit
will be accepted until 30 days
after the publish date of this
notice. The Director of the NC
Division of Water Resources
(DWR) may hold a public
hearing should there be a sig-
nificant degree of public in-
terest. Please mail comments
and/or information requests to
DWR at the above address.
interested persons may visit
the DWR at 512 N. Salisbury
Street, Raleigh, NC 27604 to
review information on file. Ad-
ditional information on NP-
DES permits and this notice
may be found on our website:
http://deq. nc.gov/aboui/divi-
sions/water-resources/water-
resources-permits
/wastewater-branch/n pdes-
wastewater/public-notices,or
by calling [phone].
Union County Public Works
[4600 Goldmine Road, Mon-
roe, NC 28112) has reques-
ted renewal of NPDES permit
NC0085359 for its Twelve Mile
Creek Water Reclamation Fa-
cility, located in Union County.
This permitted facility dis-
charges treated municipal
wastewater to Twelve Mile
Creek, a class C water in the
Catawba River Basin. Cur-
rently BOD5, NH3, dissolved
oxygen, fecal coliform, pH,
and Total phosphorus are wa-
ter quality limited. This dis-
charge may affect future alloc-
ations in this segment of
Twelve Mile Creek.
Dec. 5, 2020

Attachment A —Request for Missing Information
NPDES APPLICATION COMPLETENESS REVIEWS
FOLLOWING THE EFFECTIVE DATE OF THE
NPDES APPLICATIONS AND PROGRAM UPDATES RULE
On February 12, 2019, the EPA finalized revisions to the application requirements at 40 CFR 122.21 in the NPDES
Applications and Program Updates Rule. The final rule became effective on June 12, 2019. On and after this
date, applicants for EPA -issued permits are required to meet the new application requirements through
completion of updated application forms that conform to the final rule.
During the transition to the updated forms, the EPA anticipates that applicants may inadvertently complete and
submit applications using the older outdated forms for a period after the June 12, 2019 effective date. if this
occurs, applications submitted using the outdated Forms 1 and 2A will not conform to the regulatory
requirements for applications at 40 CFR 122.21 and should be deemed incomplete by the EPA Regions. (Note
that the final rule did not include regulatory changes pertaining to the form requirements for Forms 2B, 2C1, 2D,
2E, and 2F; therefore, submission of the outdated forms may be deemed complete at the EPA Regions'
discretion.)
Requiring applicants to transfer information from the outdated forms and resubmit the new updated forms may
be time-consuming and costly. In lieu of transferring the information and resubmitting the updated forms, EPA
Regions may consider issuing a "Notice of Incomplete Application" to the applicant requesting only the missing
information. Any information provided by the applicant in response to the notice must include the certification
statement from 40 CFR 122.22(d) and be signed in accordance with 40 CFR 122.22(a).
The EPA Regions have the discretion to determine the period of time for which they will allow applicants to
submit the outdated forms along with the missing information to accommodate applicants that may have begun
the permit application process prior to the availability of the updated forms; however, it is expected that this
practice will only be allowed for a short period of time (perhaps six months), after which the EPA Regions should
require that all applications be submitted using the updated forms.
Permittees to which the aforementioned transition period applies may complete and submit the tables
provided on Attachment A to the North Carolina DEQ's Division of Water Resources as an addendum to their
NPDES renewal applications.
These addenda only apply to facilities submitting Forms 1 and/or 2A:
Applicants submitting a renewal application addendum for Form 1 (Non-POTW, private facilities)
should fill out Table 1, found on page 2 of this document & sign and submit document.
Applicants submitting a renewal application addendum for Form 2A (Municipal & POTW's) should fill
out Table 2, found on page 3 of this document & sign and submit document.
Submit completed files to the following address:
NC DEW Division of Water Resources/Complex NPDES Permitting Unit
1617 Mail Service Center
Raleigh, North Carolina 27699- 1617
1 The final rule clarified that existing data may be used, if available, in lieu of sampling done solely for the purpose of the
application, provided that sampling was performed, collected, and analyzed no more than 4.5 years prior to submission.

Attachment A —Request for Missing Information
Table 1. EPA Application Forrn 1 Missing Information
40 CFR 122.21(f)(2)
1.1 `;
bart,[e-mail]
40 CFR
122,21(f)(3)
1.2
NAICS Code(s)
Description (optional)
40 CFR
122.21(f)(4)
1.3
[e-mail]
40 CFR
122.21(f)(9)
1.4 '
Does
•
your facility use cooling water?
Yes X No --) SKIP to Item 1.6
1.5 '
Identify the source of cooling water, (Note that facilities that use a cooling water intake structure as described at 40 CFR 125,
Subparts I and J may have additional application requirements at 40 CFR 122.21(r). Consult with your NPDES permitting
authority to determine what specific information needs to be submitted and when)
40 CFR
122.21(f)(10)
1.6 ',
Do you intend to request or renew one or more of the variances authorized at 40 CFR 122.21(m)? (Check all that apply. Consult
with your NPDES permitting authority to determine what information needs to be submitted and when.)
❑ Fundamentally different factors (CWA ❑ Water quality related effluent limitations (CWA Section
Section 301(n)) 302(b)(2))
❑ Non -conventional pollutants (CWA ❑ Thermal discharges (CWA Section 316(a))
Section 301(c) and (g))
X Not applicable
40 CFR 122.22(a) and (d)
1.7
Certification Statement
I certify under penalty of law that this document and all attachments were prepared under my direction or supervision in
accordance with a system designed to assure that qualified personnel properly gather and evaluate the information submitted.
Based on my inquiry of the person or persons who manage the system, or those persons directly responsible for gathering the
information, the information submitted is, to the best of my knowledge and belief, true, accurate, and complete. 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)
Bart T. Farmer
Official title
WRF Superintendent
Signature
,
Date signed
11123/2020

Attachment A —Request for Missing Information
Table 2. EPA Application Form 2A Missing Information
40 CFR
122.21(j)(1)
1.1 `
[e-mail]
1.2
[e-mail]
1.3.:
[e-mail]
1.4
[e-mail]
1.5.:
Do you intend to request or renew one or more of the variances authorized at 40 CFR 122.21(n)? (Check all that apply. Consult
with your NPDES permitting authority to determine what information needs to be submitted and when.)
Discharges into marine waters (CWA Section 1-1 Water quality related effluent limitation (CWA
301(h)) Section 302(b)(2))
X Not applicable
1,6
[e-mail]
40 CFR
122.210)(6)
1.7.:'
Indicate the number of SIUs and NSCIUs that discharge to the POTW.
Number of SIUs
Number of ClUs
0
0
40 CFR
122.22(a) and (d)
1.8
Certification Statement
1 certify under penalty of law that this document and all attachments were prepared under my direction or supervision in
accordance with a system designed to assure that qualified personnel property gather and evaluate the information submitted.
Based on my inquiry of the person 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.l 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)
Bart T. Farmer
Official title
WRF Superintendent
Signature
Ak
Date signed
11 /23/2020

ROY COOPER
Unrvr]U /
MICHAEL S. REGAN
�1CCY'C!N!'y
S. DANIEL SMITH
I la
NOWT H CA O'LINA
£rtwfrar murttat Quality
PERMIT NAME/OWNERSHIP CHANGE FORM
CURRENT PERMIT INFORMATION:
Permit Number: NC0085359 or NCG5 1 1 1 1
1. Facility Name: 12-Mile Creek WWTP
II. NEW OWNER/NAME INFORMATION:
1. This request for a name change is a result of:
a. Change in ownership of property/company
b. Name change only
X c. Other (please explain): Facility Name Change
2. New owner's name (name to be put on perrnit):
12-Mile Creek WRF (Water Reclamation Facility)
3. New owner's or signing official's name and title: Bart T. Farmer
(Person legally responsible for permit)
WRF Superintendent
(Title)
4. Mailing address: 4600 Goldmine Road City: Monroe
State: NC Zip Code: 28110 Phone: [phone]
E-mail address: bart.farrner cr unioneountync.gov
THIS APPLICATION PACKAGE WILL NOT BE ACCEPTED BY THE DIVISION UNLESS ALL OF
THE APPLICABLE ITEMS LISTED BELOW ARE INCLUDED WITH THE SUBMITTAL.
REQUIRED ITEMS:
1. This completed application form
2. Legal documentation of the transfer of ownership (such as a property deed, articles of incorporation,
or sales agreement)
[see reverse side of this page for signature requirements]
North Carolina Department of Environmental Quality f Division of Water Resources
1617 Mail Service Center j Raleigh, North Carolina 27699-1617
919-707-9000

NPDES Name & Ownership Change
Page 2 of 2
Applicant's Certification:
1, Bart T. Farmer , attest that this application for a name/ownership change has been reviewed and is
accurate and complete to the best of my knowledge. 1 understand that if all required parts of this
application are not completed and that if all required supporting information and attachments are not
included, this applicatiop package will be returned as incomplete.
Signature:
Date:11/23/20
THE COMPLETED APPLICATION PACKAGE, INCLUDING ALL SUPPORTING
INFORMATION & MATERIALS, SHOULD BE SENT TO THE FOLLOWING ADDDRESS:
NC DEQ / DWR / NPDES
1617 Mail Service Center
Raleigh, North Carolina 27699-1617
Version 11/2020

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
Twelve Mile Creek WWTP
IV
NC0085359
001
7.500 E
Twelve Mile Creek
03050103
C
❑ Apply WS Hardness WQC
7Q10s (cfs)
7Q10w (cfs)
30Q2 (cfs)
QA (cfs)
1Q10s (cfs)
0.100
1.50
72.70
0.09
Effluent Hardness
Upstream Hardness
Combined Hardness Chronic
Combined Hardness Acute
75.62 mg/L (Avg)
43.63 mg/L (Avg)
75.35 mg/L
75.38 mg/L
Based on 2005/2006 WER study, total copper
allowable discharge concentration = 12.9 ug/L, and
total zinc allowable discharge concentration = 171
ug/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
1.3575
FW
8.4841
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
290.6109
FW
2234.7606
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
20.2296
FW
29.6225
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
10.0423
FW
257.8038
ug/L
Mercury
Aquatic Life
NC
12
FW
0.5
ng/L
Molybdenum
Human Health
NC
2000
HH
ug/L
Nickel
Aquatic Life
NC
94.6806
FW
852.7062
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
1.9782
ug/L
Zinc
Aquatic Life
NC
322.7501
FW
320.2289
ug/L
20834 RPA, input
11/20/2020

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
Twelve Mile Creek WWTP
IV
NC0085359
001
9.000 E
Twelve Mile Creek
03050103
C
❑ Apply WS Hardness WQC
7Q10s (cfs)
7Q10w (cfs)
30Q2 (cfs)
QA (cfs)
1Q10s (cfs)
0.100
1.50
72.70
0.09
Effluent Hardness
Upstream Hardness
Combined Hardness Chronic
Combined Hardness Acute
75.62 mg/L (Avg)
43.63 mg/L (Avg)
75.39 mg/L
75.42 mg/L
Based on 2005/2006 WER study, total copper
allowable discharge concentration = 12.9 ug/L, and
total zinc allowable discharge concentration = 171
ug/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
1.3581
FW
8.4881
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
290.7535
FW
2235.7488
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
20.2399
FW
29.6376
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
10.0489
FW
257.9566
ug/L
Mercury
Aquatic Life
NC
12
FW
0.5
ng/L
Molybdenum
Human Health
NC
2000
HH
ug/L
Nickel
Aquatic Life
NC
94.7286
FW
853.0957
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
1.9800
ug/L
Zinc
Aquatic Life
NC
322.9140
FW
320.3754
ug/L
20834 RPA, input
11/20/2020

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
Twelve Mile Creek WWTP
IV
NC0085359
001
12.000 E
Twelve Mile Creek
03050103
C
❑ Apply WS Hardness WQC
7Q10s (cfs)
7Q10w (cfs)
30Q2 (cfs)
QA (cfs)
1Q10s (cfs)
0.100
1.50
72.70
0.09
Effluent Hardness
Upstream Hardness
Combined Hardness Chronic
Combined Hardness Acute
75.62 mg/L (Avg)
43.63 mg/L (Avg)
75.45 mg/L
75.47 mg/L
Based on 2005/2006 WER study, total copper
allowable discharge concentration = 12.9 ug/L, and
total zinc allowable discharge concentration = 171
ug/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
1.3589
FW
8.4931
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
290.9323
FW
2236.9874
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
20.2529
FW
29.6565
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
10.0572
FW
258.1482
ug/L
Mercury
Aquatic Life
NC
12
FW
0.5
ng/L
Molybdenum
Human Health
NC
2000
HH
ug/L
Nickel
Aquatic Life
NC
94.7887
FW
853.5840
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
1.9823
ug/L
Zinc
Aquatic Life
NC
323.1194
FW
320.5590
ug/L
20834 RPA, input
11/20/2020

REASONABLE POTENTIAL ANALYSIS
H1
Effluent Hardness
Date Data BDL=1/2DL Results
78 Std Dev.
59 Mean
94 C.V.
82 n
84 10th Per value
76 Average Value
100 Max. Value
61
57
73
87
89
88
56
66
56
56
86
78
78
63
65
50
56
52
50
60
63
56
59
76
64
63
64
60
63
100
94
160
110
130
100
100
75
66
10/12/2016
11/17/2016
12/13/2016
1/11/2017
2/16/2017
3/7/2017
4/5/2017
5/4/2017
5/10/2017
6/6/2017
7/19/2017
8/17/2017
9/19/2017
10/4/2017
11/9/2017
12/5/2017
1/10/2018
2/15/2018
3/6/2018
4/4/2018
5/16/2018
6/7/2018
7/10/2018
8/16/2018
9/11/2018
10/10/2018
11/7/2018
11/15/2018
12/4/2018
1/8/2019
2/13/2019
3/6/2019
4/10/2019
5/15/2019
6/5/2019
7/15/2019
8/7/2019
9/26/2019
10/8/2019
11/13/2019
12/5/2019
1/9/2020
2/13/2020
3/18/2020
8/5/2020
78
59
94
82
84
76
100
61
57
73
87
89
88
56
66
56
56
86
78
78
63
65
50
56
52
50
60
63
56
59
76
64
63
64
60
63
100
94
160
110
130
100
100
75
66
Use "PASTE SPECIAL.
Values" then "COPY"
. Maximum data
points = 58
H2
Upstream Hardness
22.1660
75.6222
0.2931
45
56.00 mg/L
75.62 mg/L
160.00 mg/L
Date Data BDL=1/2DL
34
38
42
58
58
46
43
41
43
33
38
37
41
43
53
42
36
53
50
7/15/2019
7/16/2019
7/17/2019
7/22/2019
7/23/2019
7/24/2019
7/29/2019
7/30/2019
7/31/2019
8/5/2019
8/6/2019
8/7/2019
2/17/2020
3/9/2020
4/6/2020
5/4/2020
6/1/2020
7/6/2020
8/3/2020
34
38
42
58
58
46
43
41
43
33
38
37
41
43
53
42
36
53
50
Results
Std Dev.
Mean
C.V.
n
10th Per value
Average Value
Max. Value
Use "PASTE SPECIAL•
Values" then "COPY"
. Maximum data
points = 58
7.5514
43.6316
0.1731
19
35.60 mg/L
43.63 mg/L
58.00 mg/L
20834 RPA, data
- 1 - 11/20/2020

REASONABLE POTENTIAL ANALYSIS
Par01 & Par02
Arsenic
Date Data BDL=1/2DL Results
1 11/7/2018 < 5 2.5 Std Dev.
2 2/6/2019 < 5 2.5 Mean
3 5/15/2019 < 5 2.5 C.V. (default)
4 10/8/2019 < 5 2.5 n
5 2/13/2020 < 5 2.5
6 8/5/2020 < 5 2.5 Mult Factor =
7 8/3/2016 < 5 2.5 Max. Value
8 5/10/2017 < 5 2.5 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
8
1.90
2.5 ug/L
4.8 ug/L
20834 RPA, data
- 2 - 11/20/2020

REASONABLE POTENTIAL ANALYSIS
Par03
Beryllium
Date Data BDL=1/2DL Results
1 11/7/2018 < 2 1 Std Dev.
2 2/6/2019 < 2 1 Mean
3 8/5/2020 < 2 1 C.V. (default)
4 8/3/2016 < 5 2.5 n
5 5/10/2017 < 5 2.5
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
0.8216
1.6000
0.6000
5
2.32
2.50 ug/L
5.80 ug/L
Date Data BDL=1/2DL Results
1 11/7/2018 < 1 0.5 Std Dev.
2 2/6/2019 < 2 1 Mean
3 5/15/2019 < 2 1 C.V. (default)
4 10/8/2019 < 5 2.5 n
5 2/13/2020 1 1
6 8/5/2020 < 0.5 0.25 Mult Factor =
7 8/3/2016 < 1 0.5 Max. Value
8 5/10/2017 < 1 0.5 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
0.7063
0.9063
0.6000
8
1.90
2.500 ug/L
4.750 ug/L
20834 RPA, data
- 3 - 11/20/2020

REASONABLE POTENTIAL ANALYSIS
Par05
Chlorides
Use "PASTE
SPECIAL -Values
then "COPY" .
Maximum data
points = 58
Date Data BDL=1/2DL Results
1 2/13/2020 32 32 Std Dev. N/A
2 Mean 32.0
3 C.V. (default) 0.6000
4 n 1
5
6 Mult Factor = 6.2
7 Max. Value 32.0 mg/L
8 Max. Pred Cw 198.4 mg/L
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
Par10
Chromium, Total
Date Data BDL=1/2DL Results
1 2/6/2019 < 5 2.5 Std Dev.
2 8/3/2016 < 5 2.5 Mean
3 5/10/2017 < 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
0.0000
2.5000
0.6000
3
3.00
2.5 pg/L
7.5 pg/L
20834 RPA, data
- 4 - 11/20/2020

REASONABLE POTENTIAL ANALYSIS
Pall
Copper
Date Data BDL=1/2DL Results
1 9/6/2016 2.8 2.8 Std Dev.
2 10/12/2016 2.1 2.1 Mean
3 11/17/2016 3 3 C.V.
4 12/13/2016 2.3 2.3 n
5 1 /11 /2017 2.2 2.2
6 2/16/2017 2.9 2.9 Mult Factor =
7 3/7/2017 2.4 2.4 Max. Value
8 4/5/2017 < 2 1 Max. Pred Cw
9 5/4/2017 < 2 1
10 5/10/2017 2.2 2.2
11 6/6/2017 2.1 2.1
12 7/19/2017 2.5 2.5
13 8/17/2017 2.2 2.2
14 9/19/2017 2.6 2.6
15 10/4/2017 2.3 2.3
16 11/9/2017 < 2 1
17 12/5/2017 < 2 1
18 1/10/2018 2.7 2.7
19 2/15/2018 3.1 3.1
20 3/6/2018 3.4 3.4
21 4/4/2018 3.5 3.5
22 5/16/2018 2.6 2.6
23 6/7/2018 3.1 3.1
24 7/10/2018 3.6 3.6
25 11/7/2018 4 4
26 2/6/2019 < 2 1
27 5/15/2019 3.7 3.7
28 10/8/2019 3.6 3.6
29 2/13/2020 4.1 4.1
30 8/5/2020 4.9 4.9
31 8/3/2016 3.9 3.9
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
1.0084
2.6710
0.3775
31
1.12
4.90 ug/L
5.49 ug/L
Date Data BDL=1/2DL Results
1 11/7/2018 < 10 5 Std Dev.
2 2/6/2019 < 10 5 Mean
3 8/5/2020 < 10 5 C.V. (default)
4 8/3/2016 < 10 5 n
5 5/10/2017 < 10 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
5.00
0.6000
5
2.32
5.0 ug/L
11.6 ug/L
20834 RPA, data
- 5 - 11/20/2020

REASONABLE POTENTIAL ANALYSIS
Par14
Lead
Date
11/7/2018 < 5
2/6/2019 < 5
5/15/2019 < 5
10/8/2019 < 5
2/13/2020 < 5
8/5/2020 < 5
8/3/2016 < 5
5/10/2017 < 5
BDL=1/2DL Results
2.5 Std Dev.
2.5 Mean
2.5 C.V. (default)
2.5 n
2.5
2.5 Mult Factor =
2.5 Max. Value
2.5 Max. Pred Cw
Use "PASTE SPECIAL.
Values" then "COPY"
. Maximum data
points = 58
Par16
Molybdenum
0.0000
2.5000
0.6000
8
1.90
2.500 ug/L
4.750 ug/L
Date Data BDL=1/2DL Results
1 11/7/2018 < 5 2.5 Std Dev. 1.4311
2 5/15/2019 < 5 2.5 Mean 3.1400
3 10/8/2019 < 5 2.5 C.V. (default) 0.6000
4 2/13/2020 5.7 5.7 n 5
5 8/5/2020 < 5 2.5
6 Mult Factor = 2.32
7 Max. Value 5.7 ug/L
8 Max. Pred Cw 13.2 ug/L
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
Use "PASTE SPECIAL•
Values" then "COPY"
. Maximum data
points = 58
20834 RPA, data
- 6 - 11/20/2020

REASONABLE POTENTIAL ANALYSIS
Par17 & Par18
Nickel
Date Data BDL=1/2DL Results
1 11/7/2018 2 2 Std Dev.
2 2/6/2019 < 5 2.5 Mean
3 5/15/2019 2 2 C.V. (default)
4 10/8/2019 3.2 3.2 n
5 2/13/2020 2.5 2.5
6 8/5/2020 2.3 2.3 Mult Factor =
7 8/3/2016 2.1 2.1 Max. Value
8 5/10/2017 < 2 1 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
Par19
Selenium
0.6234
2.2000
0.6000
8
1.90
3.2 pg/L
6.1 pg/L
Date Data BDL=1/2DL Results
1 11/7/2018 < 5 2.5 Std Dev.
2 2/6/2019 < 5 2.5 Mean
3 5/15/2019 < 5 2.5 C.V. (default)
4 10/8/2019 < 5 2.5 n
5 2/13/2020 < 5 2.5
6 8/5/2020 < 5 2.5 Mult Factor =
7 8/3/2016 < 5 2.5 Max. Value
8 5/10/2017 < 5 2.5 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
8
1.90
2.5 ug/L
4.8 ug/L
20834 RPA, data
- 7 - 11/20/2020

REASONABLE POTENTIAL ANALYSIS
Par20
Silver
Date Data BDL=1/2DL
2.5
1
0.5
0.5
0.5
0.5
2.5
2.5
11/7/2018
2/6/2019
5/15/2019
10/8/2019
2/13/2020
8/5/2020
8/3/2016
5/10/2017
5
2
1
1
1
1
5
5
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
Par21
Zinc
0.9978
1.3125
0.6000
8
1.90
2.500 ug/L
4.750 ug/L
Date Data BDL=1/2DL Results
44 Std Dev.
39 Mean
58 C.V.
52 n
50
42 Mult Factor =
56 Max. Value
37 Max. Pred Cw
36
41
36
25
33
40
23
47
49
54
44
57
51
52
49
49
57
66
39
29
32
44
59
39
28
50
45
57
78
65
65
64
63
46
40
34
47
56
52
9/6/2016
10/12/2016
11/17/2016
12/13/2016
1/11/2017
2/16/2017
3/7/2017
4/5/2017
5/4/2017
5/10/2017
6/6/2017
7/19/2017
8/9/2017
9/19/2017
10/4/2017
11/9/2017
12/5/2017
1/10/2018
2/15/2018
3/6/2018
4/4/2018
5/16/2018
6/7/2018
7/10/2018
8/16/2018
9/11/2018
11/7/2018
11/15/2018
12/4/2018
1/8/2019
2/6/2019
2/13/2019
3/6/2019
4/10/2019
5/15/2019
6/5/2019
7/15/2019
8/7/2019
9/26/2019
10/8/2019
11/13/2019
12/5/2019
1/9/2020
2/13/2020
3/18/2020
8/5/2020
8/3/2016
Use "PASTE SPECIAL.
Values" then "COPY"
. Maximum data
points = 58
11.8596
47.2128
0.2512
47
1.03
78.0 ug/L
80.3 ug/L
20834 RPA, data
- 8 - 11/20/2020

Twelve Mile Creek WWTP
NC0085359
Freshwater RPA - 95% Probability/95% Confidence Using Metal Translators
MAXIMUM DATA POINTS = 58
Qw (MGD) = 7.5000
1Q10S (cfs) = 0.09
7Q1OS (cfs) = 0.10
7Q1OW (cfs) = 1.50
30Q2 (cfs) = NO 30Q2 DATA
Avg. Stream Flow, QA (cfs) = 72.70
Receiving Stream: Twelve Mile Creek HUC 03050103
WWTP/WTP Class: IV
IWC% @ 1Q10S = 99.23175416
IWC% @ 7Q1OS = 99.14712154
IWC% @ 7Q1OW = 88.57142857
IWC% @ 30Q2 = N/A
IW%C @ QA = 13.78594723
Stream Class: C
Outfall 001
Qw = 7.5 MGD
COMBINED HARDNESS (mg/L)
Acute = 75.38 mg/L
Chronic = 75.35 mg/L
PARAMETER
TYPE
NC STANDARDS OR EPA CRITERIA
_1u)
n
REASONABLE POTENTIAL RESULTS
RECOMMENDED ACTION
Chronic Stapda d Acute
n # Det. Max Pred Cw Allowable Cw
Arsenic
Arsenic
C
C
150 FW(7Q10s) 340
10 HH/WS(Qavg)
ug/L
ug/L
8 0
Note: n < 9
Limited data set
4.8
C.V.(default)
NO DETECTS
Acute (FW): 342.6
------------------------------------------------
Chronic (FW): 151.3
Max MDL =5_______________________________________
Chronic (HH): 72.5
Max MDL = 5
No RP, Predicted Max < 50% of Allowable Cw - No
Monitoring required
Beryllium
NC
6.5 FW(7Q10s) 65
ug/L
5 0
Note: n < 9
Limited data set
5.80
C.V. (default)
NO DETECTS
Acute: 65.50
____ _ ______ _____
Chronic: 6.56
Max MDL = 5
_ _ _ _ _ _ _ _ _ _ _ _ _ _
All values reported non -detect < 5 ug/L and 2 ug/L -
No Monitoring required
Cadmium
NC
1.3575 FW(7Q10s) 8.4841
ug/L
8 1
Note: n < 9
Limited data set
4.750
C.V. (default)
Acute: 8.550
_ _ _ _ _ _ _ -_ _ _ _ _
--1-.3-6-9
Chronic: 1.369
1 value(s) > Allowable Cw
_ _ _ _ _ _ _ _ _ _ _ _ _
RP for limited dataset, no detected values above
allowable discharge concentration - apply quarterly
monitoring
Chlorides
NC
230 FW(7Q10s)
mg/L
1 1
Note: n < 9
Limited data set
198.4
C.V. (default)
Acute: NO WQS
____ _ ______ _____
Chronic: 232.0
No value > Allowable Cw
_ _ _ _ _ _ _ _ _ _ _ _____
One value reported at 32 mg/L - No monitoring
required.
Chromium III
NC
290.6109 FW(7Q10s) 2234.7606
µg/L
0 0
N/A
Acute: 2,252.1
--_ _ ----_ _
--293.1--------------------------------
Chronic:
Chromium VI
NC
11 FW(7Q10s) 16
µg/L
0 0
N/A
Acute: 16.1
--_ _ ----- _ _
---------------------------------
Chronic: 11.1
Chromium, Total
NC
µg/L
3 0
Note: n < 9
Limited data set
7.5
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
12.9000 FW(7Q10s) 18.5000
ug/L
31 26
5.49
Acute: 18.6
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _
Chronic: 13.0
No value > Allowable Cw
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _
No RP, Predicted Max < 50% of Allowable Cw - No
Monitoring required
Cyanide
NC
5 FW(7Q10s) 22
10
ug/L
5 0
Note: n < 9
Limited data set
11.6
C.V. (default)
NO DETECTS
Acute: 22.2
____ _ ____________
Chronic: 5.0
Max MDL = 10
_ _ _ _ _ _ _ ___ _ _ _____
All values reported non -detect < 10 ug/L - No
Monitoring required
Page 1 of 2
20834 RPA, rpa
11/20/2020

Twelve Mile Creek WWTP
NC0085359
Freshwater RPA - 95% Probability/95% Confidence Using Metal Translators
Outfall 001
Qw = 7.5 MGD
Lead
NC
10.0423 FW(7Q10s) 257.8038
ug/L
8 0
Note: n < 9
Limited data set
4.750
C.V. (default)
NO DETECTS
Acute: 259.800
_ _ _ _ _ _ _ _ _ _ _ _ _
Chronic: 10.129
Max MDL = 5
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _
No RP, Predicted Max < 50% of Allowable Cw - No
Monitoring required
Acute (FW): 859.3
Nickel
NC
94.6806 FW(7Q10s) 852.7062
µg/L
8 6
6.1
_ _ _ _ _—_ _ _ --_—_-------_—_---_—_-------_—_—
Chronic (FW)—95.5
Note: n < 9
C.V. (default)
No value > Allowable Cw _ _ _
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _
Nickel
NC
25.0000 WS(7Q10s)
µg/L
Limited data set
Chronic (WS): 25.2
No RP, Predicted Max < 50% of Allowable Cw - No
No value > Allowable Cw
Monitoring required
Acute: 56.4
Selenium
NC
5 FW(7Q10s) 56
ug/L
8 0
4.8
____ _________________________________________
Note: n < 9
C.V. (default)
Chronic: 5.0
All values reported non -detect < 5 ug/L - No
Limited data set
NO DETECTS
Max MDL = 5
Monitoring required
Acute: 1.993
Silver
NC
0.06 FW(7Q10s) 1.9782
ug/L
8 0
4.750
All values reported non -detect < 5 ug/L, < 2 ug/L, and
Note: n < 9
Limited data set
C.V. (default)
NO DETECTS
Chronic: 0.061
Max MDL = 5
< 1 ug/L - No monitoring required. Permittee shall
continue to report to PQL of 1 ug/L.
Acute: 172.324
No RP, Predicted Max < 50% of Allowable Cw - No
Zinc
NC
171.0000 FW(7Q10s) 171.0000
ug/L
47 47
80.3
Monitoring required
--- ----------------------------------- Chronic: 172.471
No value > Allowable Cw
Page 2 of 2
20834 RPA, rpa
11/20/2020

Twelve Mile Creek WWTP
NC0085359
Freshwater RPA - 95% Probability/95% Confidence Using Metal Translators
MAXIMUM DATA POINTS = 58
Qw (MGD) = 9.0000
1Q1OS (cfs) = 0.09
7Q10S (cfs) = 0.10
7Q10W (cfs) = 1.50
30Q2 (cfs) = NO 30Q2 DATA
Avg. Stream Flow, QA (cfs) = 72.70
Receiving Stream: Twelve Mile Creek HUC 03050103
WWTP/WTP Class: IV
IWC% @ 1Q1OS = 99.35897436
IWC% @ 7Q10S = 99.28825623
IWC% @ 7Q10W = 90.29126214
IWC% @ 30Q2 = N/A
IW%C @ QA = 16.09924986
Stream Class: C
Outfall 001
Qw = 9 MGD
COMBINED HARDNESS (mg/L)
Acute = 75.42 mg/L
Chronic = 75.39 mg/L
PARAMETER
TYPE
NC STANDARDS OR EPA CRITERIA
_1u)
n
REASONABLE POTENTIAL RESULTS
RECOMMENDED ACTION
Chronic Stapda d Acute
n # Det. Max Pred Cw Allowable Cw
Arsenic
Arsenic
C
C
150 FW(7Q10s) 340
10 HH/WS(Qavg)
ug/L
ug/L
8 0
Note: n < 9
Limited data set
4.8
C.V.(default)
NO DETECTS
Acute (FW): 342.2
------------------------------------------------
Chronic (FW): 151.1
Max MDL =5_______________________________________
Chronic (HH): 62.1
Max MDL = 5
No RP, Predicted Max < 50% of Allowable Cw - No
Monitoring required
Beryllium
NC
6.5 FW(7Q10s) 65
ug/L
5 0
Note: n < 9
Limited data set
5.80
C.V. (default)
NO DETECTS
Acute: 65.42
____ _ ______ _____
Chronic: 6.55
Max MDL = 5
_ _ _ _ _ _ _ _ _ _ _ _ _ _
All values reported non -detect < 5 ug/L and 2 ug/L -
No Monitoring required
Cadmium
NC
1.3581 FW(7Q10s) 8.4881
ug/L
8 1
Note: n < 9
Limited data set
4.750
C.V. (default)
Acute: 8.543
_ _ _ _ _ _ _ -_ _ _ _ _
--1-.3-6-8
Chronic: 1.368
1 value(s) > Allowable Cw
_ _ _ _ _ _ _ _ _ _ _ _ _
RP for limited dataset, no detected values above
allowable discharge concentration - apply quarterly
monitoring
Chlorides
NC
230 FW(7Q10s)
mg/L
1 1
Note: n < 9
Limited data set
198.4
C.V. (default)
Acute: NO WQS
____ _ ______ _____
Chronic: 231.6
No value > Allowable Cw
_ _ _ _ _ _ _ _ _ _ _ _____
One value reported at 32 mg/L - No monitoring
required.
Chromium III
NC
290.7535 FW(7Q10s) 2235.7488
µg/L
0 0
N/A
Acute: 2,250.2
--_ _ ----_ _
--292.8--------------------------------
Chronic:
Chromium VI
NC
11 FW(7Q10s) 16
µg/L
0 0
N/A
Acute: 16.1
--_ _ ----- _ _
---------------------------------
Chronic: 11.1
Chromium, Total
NC
µg/L
3 0
Note: n < 9
Limited data set
7.5
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
12.9000 FW(7Q10s) 18.5000
ug/L
31 26
5.49
Acute: 18.6
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _
Chronic: 13.0
No value > Allowable Cw
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _
No RP, Predicted Max < 50% of Allowable Cw - No
Monitoring required
Cyanide
NC
5 FW(7Q10s) 22
10
ug/L
5 0
Note: n < 9
Limited data set
11.6
C.V. (default)
NO DETECTS
Acute: 22.1
____ _ ____________
Chronic: 5.0
Max MDL = 10
_ _ _ _ _ _ _ ___ _ _ _____
All values reported non -detect < 10 ug/L - No
Monitoring required
Page 1 of 2
20834 RPA, rpa
11/20/2020

Twelve Mile Creek WWTP
NC0085359
Freshwater RPA - 95% Probability/95% Confidence Using Metal Translators
Outfall 001
Qw = 9 MGD
Lead
NC
10.0489 FW(7Q10s) 257.9566
ug/L
8 0
Note: n < 9
Limited data set
4.750
C.V. (default)
NO DETECTS
Acute: 259.621
_ _ _ _ _ _ _ _ _ _ _ _ _
Chronic: 10.121
Max MDL = 5
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _
No RP, Predicted Max < 50% of Allowable Cw - No
Monitoring required
Acute (FW): 858.6
Nickel
NC
94.7286 FW(7Q10s) 853.0957
µg/L
8 6
6.1
_ _ _ _ _—_ _ _ --_—_-------_—_---_—_-------_—_—
Chronic (FW)—95.4
Note: n < 9
C.V. (default)
No value > Allowable Cw _ _ _
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _
Nickel
NC
25.0000 WS(7Q10s)
µg/L
Limited data set
Chronic (WS): 25.2
No RP, Predicted Max < 50% of Allowable Cw - No
No value > Allowable Cw
Monitoring required
Acute: 56.4
Selenium
NC
5 FW(7Q10s) 56
ug/L
8 0
4.8
____ _________________________________________
Note: n < 9
C.V. (default)
Chronic: 5.0
All values reported non -detect < 5 ug/L - No
Limited data set
NO DETECTS
Max MDL = 5
Monitoring required
Acute: 1.993
Silver
NC
0.06 FW(7Q10s) 1.9800
ug/L
8 0
4.750
All values reported non -detect < 5 ug/L, < 2 ug/L, and
Note: n < 9
Limited data set
C.V. (default)
NO DETECTS
Chronic: 0.060
Max MDL = 5
< 1 ug/L - No monitoring required. Permittee shall
continue to report to PQL of 1 ug/L.
Acute: 172.103
No RP, Predicted Max < 50% of Allowable Cw - No
Zinc
NC
171.0000 FW(7Q10s) 171.0000
ug/L
47 47
80.3
Monitoring required
--- ----------------------------------- Chronic: 172.226
No value > Allowable Cw
Page 2 of 2
20834 RPA, rpa
11/20/2020

Twelve Mile Creek WWTP
NC0085359
Freshwater RPA - 95% Probability/95% Confidence Using Metal Translators
MAXIMUM DATA POINTS = 58
Qw (MGD) = 12.0000
1Q10S (cfs) = 0.09
7Q1OS (cfs) = 0.10
7Q1OW (cfs) = 1.50
30Q2 (cfs) = NO 30Q2 DATA
Avg. Stream Flow, QA (cfs) = 72.70
Receiving Stream: Twelve Mile Creek HUC 03050103
WWTP/WTP Class: IV
IWC% @ 1Q10S = 99.51845907
IWC% @ 7Q1OS = 99.46524064
IWC% @ 7Q1OW = 92.53731343
IWC% @ 30Q2 = N/A
IW%C @ QA = 20.37239869
Stream Class: C
Outfall 001
Qw = 12 MGD
COMBINED HARDNESS (mg/L)
Acute = 75.47 mg/L
Chronic = 75.45 mg/L
PARAMETER
TYPE
NC STANDARDS OR EPA CRITERIA
_1u)
n
REASONABLE POTENTIAL RESULTS
RECOMMENDED ACTION
Chronic Stapda d Acute
n # Det. Max Pred Cw Allowable Cw
Arsenic
Arsenic
C
C
150 FW(7Q10s) 340
10 HH/WS(Qavg)
ug/L
ug/L
8 0
Note: n < 9
Limited data set
4.8
C.V.(default)
NO DETECTS
Acute (FW): 341.6
------------------------------------------------
Chronic (FW): 150.8
Max MDL =5_______________________________________
Chronic (HH): 49.1
Max MDL = 5
No RP, Predicted Max < 50% of Allowable Cw - No
Monitoring required
Beryllium
NC
6.5 FW(7Q10s) 65
ug/L
5 0
Note: n < 9
Limited data set
5.80
C.V. (default)
NO DETECTS
Acute: 65.31
____ _ ______ _____
Chronic: 6.53
Max MDL = 5
_ _ _ _ _ _ _ _ _ _ _ _ _ _
All values reported non -detect < 5 ug/L and 2 ug/L -
No Monitoring required
Cadmium
NC
1.3589 FW(7Q10s) 8.4931
ug/L
8 1
Note: n < 9
Limited data set
4.750
C.V. (default)
Acute: 8.534
_ _ _ _ _
_ _ _ _ _ _ _ _ -1-.3-6-6
Chronic: 1.366
1 value(s) > Allowable Cw
_ _ _ _ _ _ _ _ _ _ _ _ _
RP for limited dataset, no detected values above
allowable discharge concentration - apply quarterly
monitoring
Chlorides
NC
230 FW(7Q10s)
mg/L
1 1
Note: n < 9
Limited data set
198.4
C.V. (default)
Acute: NO WQS
____ _ ______ _____
Chronic: 231.2
No value > Allowable Cw
_ _ _ _ _ _ _ _ _ _ _ _____
One value reported at 32 mg/L - No monitoring
required.
Chromium III
NC
290.9323 FW(7Q10s) 2236.9874
µg/L
0 0
N/A
Acute: 2,247.8
--_ _ ----_ _
--292.5--------------------------------
Chronic:
Chromium VI
NC
11 FW(7Q10s) 16
µg/L
0 0
N/A
Acute: 16.1
--_ _ ----- _ _
---------------------------------
Chronic: 11.1
Chromium, Total
NC
µg/L
3 0
Note: n < 9
Limited data set
7.5
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
12.9000 FW(7Q10s) 18.5000
ug/L
31 26
5.49
Acute: 18.6
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _
Chronic: 13.0
No value > Allowable Cw
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _
No RP, Predicted Max < 50% of Allowable Cw - No
Monitoring required
Cyanide
NC
5 FW(7Q10s) 22
10
ug/L
5 0
Note: n < 9
Limited data set
11.6
C.V. (default)
NO DETECTS
Acute: 22.1
____ _ ____________
Chronic: 5.0
Max MDL = 10
_ _ _ _ _ _ _ ___ _ _ _____
All values reported non -detect < 10 ug/L - No
Monitoring required
Page 1 of 2
20834 RPA, rpa
11/20/2020

Twelve Mile Creek WWTP
NC0085359
Freshwater RPA - 95% Probability/95% Confidence Using Metal Translators
Outfall 001
Qw = 12 MGD
Lead
NC
10.0572 FW(7Q10s) 258.1482
ug/L
8 0
Note: n < 9
Limited data set
4.750
C.V. (default)
NO DETECTS
Acute: 259.397
_ _ _ _ _ _ _ _ _ _ _ _ _
Chronic: 10.111
Max MDL = 5
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _
No RP, Predicted Max < 50% of Allowable Cw - No
Monitoring required
Acute (FW): 857.7
Nickel
NC
94.7887 FW(7Q10s) 853.5840
µg/L
8 6
6.1
__ _ _ _—_ _ _ --_—_-------_—_---_—_-------_—_—
Chronic (FW)—95.3
Note: n < 9
C.V. (default)
No value > Allowable Cw _ _ _
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _
Nickel
NC
25.0000 WS(7Q10s)
µg/L
Limited data set
Chronic (WS): 25.1
No RP, Predicted Max < 50% of Allowable Cw - No
No value > Allowable Cw
Monitoring required
Acute: 56.3
Selenium
NC
5 FW(7Q10s) 56
ug/L
8 0
4.8
____ _________________________________________
Note: n < 9
C.V. (default)
Chronic: 5.0
All values reported non -detect < 5 ug/L - No
Limited data set
NO DETECTS
Max MDL = 5
Monitoring required
Acute: 1.992
Silver
NC
0.06 FW(7Q10s) 1.9823
ug/L
8 0
4.750
All values reported non -detect < 5 ug/L, < 2 ug/L, and
Note: n < 9
Limited data set
C.V. (default)
NO DETECTS
Chronic: 0.060
Max MDL = 5
< 1 ug/L - No monitoring required. Permittee shall
continue to report to PQL of 1 ug/L.
Acute: 171.827
No RP, Predicted Max < 50% of Allowable Cw - No
Zinc
NC
171.0000 FW(7Q10s) 171.0000
ug/L
47 47
80.3
Monitoring required
--- ----------------------------------- Chronic: 171.919
No value > Allowable Cw
Page 2 of 2
20834 RPA, rpa
11/20/2020

Permit No. NC0085359
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 April6, 2016, with some exceptions. Therefore, metal limits in draft
permits out to public notice after April6, 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[ln hardness]-4.4451 }
Chromium III, Acute
WER*0.316 • e^{0.8190[ln hardness]+3.7256}
Chromium III, Chronic
WER*0.860 • e^{0.8190[ln hardness]+0.6848}
Copper, Acute
WER*0.960 • e^{0.9422[ln hardness]-1.700}
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. NC0085359
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. NC0085359
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. NC0085359
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)]
75.62
Data provided in DMRs 09/2016-
09/2020
Average Upstream Hardness (mg/L)
[Total as, CaCO3 or (Ca+Mg)]
43.63
Data provided in DMRs 09/2016-
09/2020
7Q10 summer (cfs)
0.1
NPDES Files
1Q10 (cfs)
0.09
Calculated in RPA
Permitted Flow (MGD)
7.5
NPDES Files
Date: 11/18/2020
Permit Writer: Nick Coco
Page 4 of 4

NC0085359 Twelve Mile Creek WWTP 11/19/2020
BOD monthly removal rate
Month RR (%) Month RR (%)
September-16
October-16
November-16
December-16
January-17
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
99.13
99.06
99.20
99.18
98.83
98.99
98.92
98.70
98.85
99.05
99.12
99.14
99.04
99.26
99.18
99.20
98.90
98.88
98.97
98.77
99.15
99.19
99.23
99.20
99.08
98.89
97.29
98.53
98.28
98.55
March-19
April-19
May-19
June-19
July-19
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
Overall BOD removal rate
98.57
97.00
97.70
98.14
98.32
98.90
98.91
98.18
98.12
98.23
98.32
98.23
97.28
97.93
97.30
98.03
98.17
97.88
98.60
TSS monthly removal rate
Month RR (%) Month RR (%)
September-16
October-16
November-16
December-16
January-17
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
98.84
98.83
98.89
98.94
98.57
98.88
98.76
98.54
98.81
98.78
99.08
98.93
98.79
99.04
99.03
98.87
98.77
98.79
98.85
98.00
99.00
99.02
98.85
98.95
98.65
99.01
97.09
97.67
95.42
98.03
March-19
April-19
May-19
June-19
July-19
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
Overall TSS removal rate
98.03
93.97
97.05
98.04
98.20
98.46
98.21
98.44
98.42
97.12
97.94
97.42
97.19
98.33
97.00
98.30
98.34
97.72
98.25

Instream Temperature Summary NC0085359
Date
Upstream [degC]
Downstream 1 [degC]
Downstream 2 [degC]
9/6/2016
22.1
24.3
24.6
9/7/2016
22.3
23.5
24.2
9/8/2016
22.7
24.7
24.5
9/12/2016
23.6
24.8
24.6
9/13/2016
23.1
24.8
24.8
9/14/2016
23.8
25.3
25.4
9/19/2016
24.3
25.8
25.9
9/20/2016
23.8
24.7
24.5
9/21/2016
23.1
24
24.1
9/26/2016
22.6
24.3
24.3
9/27/2016
22.6
22.9
22.9
9/28/2016
22.5
24
23.5
10/3/2016
19.7
22.6
22.5
10/12/2016
15.2
17.1
16.9
10/18/2016
17.5
19.9
21.2
10/25/2016
13.7
17.7
17.4
10/31/2016
16.4
20.8
20.2
11/7/2016
12.3
18.9
16.9
11/14/2016
11.2
18.1
16.3
11 /21 /2016
8.2
15.6
13.6
11/28/2016
9.5
16.4
15.2
12/8/2016
11.4
13.7
12.9
12/14/2016
9.6
14.6
13.3
12/21/2016
6.8
10.6
9.6
12/28/2016
12.7
16.2
15.1
1/5/2017
8.9
10.3
10
1/11/2017
6.8
7.9
7.3
1/18/2017
16.3
18
17.3
1/26/2017
13
13
13.7
1 /31 /2017
7.8
9.3
9.6
2/8/2017
12.4
13.6
14.3
2/16/2017
10.3
10.5
10.4
2/23/2017
15
16.1
17.3
2/28/2017
13.9
16.4
16
3/7/2017
14
14.9
15.4
3/15/2017
6.3
6.6
6.8
3/21/2017
14.2
14.8
13.9
3/29/2017
18.2
18.2
17.9
4/5/2017
17.9
18
18.4
4/11/2017
17
17.7
16.9
4/19/2017
16.7
17.1
17.9
4/27/2017
18.7
18.7
18.9
5/1/2017
21
21.2
21
5/11/2017
19.6
19.7
19.5
5/15/2017
20.4
20.6
19.9
5/24/2017
20.8
20.8
20.6
5/31/2017
21.3
21.8
22.3
6/6/2017
22.3
22.4
22.7
6/7/2017
21.1
20.9
21.1
6/8/2017
20.2
19.9
20.6
6/12/2017
21.2
21.9
22.7
6/13/2017
21.9
22.4
22.8
P1

Instream Temperature Summary NC0085359
Date
Upstream [degC]
Downstream 1 [degC]
Downstream 2 [degC]
6/14/2017
24
23.6
23.5
6/19/2017
23.8
23.8
23.7
6/21/2017
22.6
22.6
22.3
6/22/2017
23.1
23.1
23
6/26/2017
22
22.3
22.8
6/27/2017
21.2
21.5
21.9
6/28/2017
20.6
20.9
20.9
7/3/2017
25
25
24.7
7/5/2017
24.1
24.1
23.9
7/6/2017
24
24
23.9
7/10/2017
23.7
23.8
23.7
7/11/2017
23.7
23.7
23.6
7/12/2017
24.4
24.5
24.3
7/17/2017
23.7
23.9
23.7
7/18/2017
24.1
24.1
24.1
7/19/2017
23.6
23.9
23.7
7/24/2017
24.3
24.2
24.1
7/25/2017
24.8
24.9
24.7
7/26/2017
24.3
24.2
24.1
7/31/2017
21.9
24.1
22.2
8/1/2017
21.5
22.2
22.3
8/2/2017
21.9
23.1
22.8
8/7/2017
23.5
24.1
23.8
8/8/2017
23.3
23.4
23.3
8/9/2017
22.5
22.8
22.4
8/14/2017
24.2
24.3
24.1
8/15/2017
24.4
24.4
24.3
8/16/2017
24.7
24.9
24.6
8/21/2017
26.3
27
26.3
8/23/2017
25.1
25.4
25.1
8/24/2017
23.6
23.9
23.7
8/28/2017
21.5
22.8
22.3
8/29/2017
20.7
22.3
22
8/30/2017
20.7
22.4
21.9
9/6/2017
21.6
22.8
22.7
9/7/2017
19.6
20
19.7
9/8/2017
18.9
19.9
19.9
9/11/2017
18.8
19
18.9
9/13/2017
19.3
19.7
19.4
9/14/2017
20.4
20.5
20.4
9/18/2017
20.9
21.7
21.7
9/19/2017
20.6
21.4
21.6
9/20/2017
20.9
22.2
21.9
9/25/2017
20.8
22
21.9
9/26/2017
21.3
22.7
22.3
9/27/2017
23
24.2
24.1
10/2/2017
17.9
20.6
19.7
10/10/2017
22.8
24.2
24
10/18/2017
15.2
17.9
17.4
10/25/2017
15.1
16.1
16.3
10/30/2017
11.3
16.7
15.1
11/6/2017
17.5
20.7
19.8
P2

Instream Temperature Summary NC0085359
Date
Upstream [degC]
Downstream 1 [degC]
Downstream 2 [degC]
11/14/2017
10.7
12.8
12.6
11/20/2017
10.3
15.6
14.1
11/28/2017
9.3
15.2
13.7
12/4/2017
11.5
15.8
14.9
12/14/2017
8.3
12.4
11.2
12/19/2017
11.8
15.3
14.7
12/27/2017
8.3
10.8
10.1
1/4/2018
2.2
7.3
6
1/10/2018
5.1
10.9
10.8
1/16/2018
5
7.8
6.3
1/22/2018
8
10.9
9.5
2/1/2018
8.6
9.2
9.1
2/6/2018
10
10.1
10.2
2/15/2018
13.3
14.3
14.2
2/21/2018
18.6
17.8
17.7
2/27/2018
13.7
14.2
13.7
3/6/2018
10.6
11.3
11.4
3/14/2018
8.6
9
8.8
3/20/2018
16.3
16.2
16.2
3/27/2018
10.9
11.2
11.3
4/3/2018
17.1
16.8
16.7
4/10/2018
12.9
18.2
13.4
4/18/2018
16.3
17.5
16.4
4/26/2018
18
17.7
17.8
5/1/2018
16
17
16.1
5/8/2018
18.9
20.4
18.9
5/15/2018
22.5
23.2
22.4
5/22/2018
22.4
23.2
22.6
5/29/2018
23.4
23.5
23.5
6/4/2018
24.2
24.3
23.9
6/5/2018
22.2
23.9
22.2
6/6/2018
22.4
23.5
22.4
6/11/2018
25.2
25.7
24.7
6/12/2018
21.8
22.1
22.2
6/13/2018
22.8
23.5
23
6/18/2018
26.5
27.1
26.6
6/19/2018
26.4
26.7
25.8
6/20/2018
27.3
27.6
26.8
6/25/2018
25.8
27.1
25.3
6/26/2018
24.4
25.7
24.3
6/27/2018
24.8
24.8
24.9
7/2/2018
26.1
26.8
26.2
7/3/2018
26.7
28.7
27.3
7/5/2018
26.4
28.1
25.9
7/10/2018
23.8
26.3
24.9
7/11/2018
24.7
27
25.3
7/12/2018
25.4
27
25.9
7/16/2018
24
24.6
24.4
7/17/2018
24.3
24.7
24.5
7/18/2018
24.4
24.7
24.5
7/23/2018
23.4
24.9
23.9
7/24/2018
23.4
23.9
24.5
P3

Instream Temperature Summary NC0085359
Date
Upstream [degC]
Downstream 1 [degC]
Downstream 2 [degC]
7/25/2018
24.8
25
25.5
7/30/2018
25.3
26.2
26.1
7/31/2018
25
25.5
25.4
8/1/2018
24.7
25
25
8/6/2018
25.4
27
26
8/7/2018
25
25.9
25.1
8/8/2018
25.7
26.9
25.8
8/13/2018
24.5
25.2
24.5
8/14/2018
25
26.2
25.8
8/15/2018
25
25.8
25.7
8/20/2018
24.9
25.9
25.6
8/21/2018
24.5
25.5
25.2
8/22/2018
25.1
26.3
25.1
8/27/2018
24.8
26.3
25.4
8/28/2018
25.3
26.2
25.6
8/29/2018
25.5
26.4
25.6
9/4/2018
25.2
26.5
26.4
9/5/2018
25.2
26.5
25.8
9/6/2018
25.5
26.8
26.3
9/10/2018
25.5
26.2
25.2
9/11/2018
23.4
24.5
24.1
9/12/2018
24.3
25.4
24.8
9/19/2018
24
24.2
23.9
9/20/2018
23.8
24.6
23.9
9/21/2018
23.9
24.9
24
9/24/2018
22.3
23.1
22.9
9/25/2018
22.5
23.5
23
9/26/2018
23.3
24.4
23.7
10/1/2018
22.2
23.7
23
10/8/2018
23.4
24.9
24.2
10/16/2018
20.2
21.1
20.9
10/23/2018
13.4
16
15.7
10/29/2018
14.2
15
15.2
11/5/2018
14.8
14.8
14.7
11/14/2018
11.7
11.8
11.8
11/19/2018
12
12.9
12.8
11/26/2018
11.5
12.1
12.2
12/3/2018
15
15.1
15.2
12/13/2018
7.9
7.9
8.7
12/18/2018
9.9
10.6
10.6
12/26/2018
8.6
9.3
9.1
12/31/2018
13.1
13.6
13.6
1/8/2019
12.9
13.5
13
1/15/2019
8.2
9.8
8.9
1/22/2019
5.2
5.8
5.9
1/28/2019
7.4
9.1
8.1
2/4/2019
8.3
10.8
8.9
2/11/2019
8.6
10.1
9.9
2/18/2019
9.6
11
9.9
2/25/2019
10.3
10.6
10.4
3/6/2019
9
8.7
9
3/11/2019
12.7
14.3
12.7
P4

Instream Temperature Summary NC0085359
Date
Upstream [degC]
Downstream 1 [degC]
Downstream 2 [degC]
3/18/2019
11
12.1
11.5
3/25/2019
14.2
15.8
14.1
4/1/2019
13
12.6
13.6
4/8/2019
16.8
17.7
16.6
4/16/2019
15.8
15.9
16.1
4/22/2019
13.8
14.2
14.4
4/29/2019
17.8
18
18.1
5/6/2019
20.5
20.4
20.4
5/13/2019
20.4
20.3
20.4
5/21/2019
21.3
21.3
21.6
5/28/2019
22.9
22.9
23.2
6/3/2019
21.2
21.9
22
6/4/2019
20.7
21.4
21.6
6/5/2019
22.3
22.9
22.5
6/10/2019
23.3
23.3
23.2
6/11/2019
23
23
23.1
6/12/2019
21.1
21.4
21.6
6/17/2019
21.9
22.3
22.6
6/18/2019
23.1
23.3
23.7
6/19/2019
22.9
23.2
23.3
6/24/2019
22.8
23
23.2
6/25/2019
23.2
23.3
23.5
6/26/2019
23.2
23.3
23.5
7/1/2019
24.4
24.5
24.7
7/2/2019
24
24.3
24.5
7/3/2019
24.8
24.8
25.2
7/8/2019
26.6
27.8
26.4
7/9/2019
24.8
25.1
25
7/10/2019
25.2
25.2
25
7/15/2019
25.9
27
25.5
7/16/2019
26.4
28
26.2
7/17/2019
25.9
27.6
25.9
7/22/2019
25.1
25.1
25.2
7/23/2019
24.6
24.7
24.7
7/24/2019
21.6
21.9
21.8
7/29/2019
22.3
23.4
23.5
7/30/2019
22.3
23.6
23.6
7/31/2019
22.5
23.8
23.9
8/5/2019
22.7
23
23
8/6/2019
22.7
23.2
23.6
8/7/2019
23.2
23.9
23.9
8/12/2019
24.1
24.8
25.1
8/13/2019
24.5
25
25.1
8/14/2019
24.1
24.7
24.7
8/19/2019
24.9
25.1
25.3
8/20/2019
24
24.7
24.7
8/21/2019
23.6
23.6
23.5
8/26/2019
21.2
21.7
21.7
8/27/2019
21.2
22.1
22
8/28/2019
22.2
22.8
22.9
9/3/2019
22
23.7
23.6
9/4/2019
22.3
23.8
23.8
P5

Instream Temperature Summary NC0085359
Date
Upstream [degC]
Downstream 1 [degC]
Downstream 2 [degC]
9/5/2019
22.7
24.1
24
9/9/2019
22.8
24.2
24.1
9/10/2019
23.6
24.8
24.9
9/11/2019
24
25.1
25
9/16/2019
22.3
23.1
23
9/17/2019
22.7
23.5
23.7
9/18/2019
22
23.2
23.1
9/23/2019
20
22.5
22.2
9/24/2019
20.6
23
22.7
9/25/2019
20.5
22.6
22.3
10/1/2019
23.3
24.6
24.5
10/7/2019
19.9
22.5
21.9
10/15/2019
16.9
20.2
19.4
10/21/2019
15.8
16.7
16.7
10/28/2019
16.9
17.8
18.1
11/4/2019
10.6
15.1
14.6
11/12/2019
10.5
13.7
13.8
11/18/2019
9
11.9
12
11/25/2019
10.2
11.3
11.5
12/2/2019
11.1
11.9
12.1
12/9/2019
8
11.4
11.7
12/16/2019
10.9
10.6
9.6
12/26/2019
8.5
8.8
9.1
12/30/2019
14.3
14.6
14.8
1/6/2020
9.1
9.4
9.7
1/13/2020
15.1
15
15.4
1 /21 /2020
5.3
6.8
7.3
1/27/2020
8.4
8.8
9.3
2/3/2020
8.9
9.3
9.6
2/10/2020
10.7
9.6
9.9
2/17/2020
9.9
10.4
10.6
2/24/2020
9.4
10.1
10.5
3/3/2020
11.9
12.6
12.7
3/9/2020
11
11
11
3/16/2020
14.2
14.7
14.9
3/23/2020
15
8
15.9
3/30/2020
19
19.3
19.6
4/6/2020
17.2
17
17.3
4/14/2020
17.6
17.8
17.9
4/20/2020
9.1
15
15.1
4/27/2020
15.5
16.1
16.5
5/4/2020
18.7
18.6
18.5
5/11/2020
14.1
14.6
14.9
5/18/2020
19.3
19.8
20
5/26/2020
20.1
20.1
20.2
6/1/2020
19.7
19.9
19.8
6/2/2020
19.2
19.2
19.4
6/3/2020
20.3
20.2
20.5
6/8/2020
23.4
23.2
23
6/9/2020
23.7
23.5
23.6
6/10/2020
23.8
26.6
23.6
6/15/2020
20.2
20.7
20.9
P6

Instream Temperature Summary NC0085359
Date
Upstream [degC]
Downstream 1 [degC]
Downstream 2 [degC]
6/16/2020
18.3
19
19.1
6/17/2020
18.1
18.6
18.8
6/22/2020
22.1
22.2
22.5
6/23/2020
22.6
22.6
22.8
6/24/2020
22.5
22.6
22.7
6/29/2020
23
23.1
23.3
6/30/2020
23.5
24.3
23.7
7/1/2020
23
23
22.9
7/6/2020
23.6
23.7
23.9
7/7/2020
23.3
23.5
23.6
7/8/2020
23.2
23.4
23.5
7/13/2020
24.1
24.2
24.4
7/14/2020
24
24.2
24.3
7/15/2020
25.2
25.1
25.4
7/20/2020
25.6
25.4
25.6
7/21/2020
25.1
25
25
7/22/2020
24.7
24.5
24.4
7/27/2020
24.8
24.8
24.8
7/28/2020
25.2
25.2
25.4
7/29/2020
25.3
25.3
25.3
8/3/2020
25.3
25.3
25.4
8/4/2020
24.4
24.3
24.1
8/5/2020
24.3
24.4
24.3
8/10/2020
24.2
24.4
24.2
8/11/2020
23.6
24.4
24.2
8/12/2020
24.3
24.8
24.8
8/17/2020
23.4
23.6
23.5
8/18/2020
23.3
23.5
23.5
8/19/2020
23.4
23.8
23.8
8/24/2020
23.5
23.8
23.7
8/25/2020
23.5
23.9
23.8
8/26/2020
23.7
24.1
24
8/31/2020
24.4
24.8
24.8
Average
19.4
20.4
20.1
Max
27.3
28.7
27.3
Min
2.2
5.8
5.9
p-value
<
.05
>
.05
P7
Note: Student's t-tests run to compare both downtream locations to the upstream sample location.

Instream Temperature Summary NC0085359
Date
Upstream [degC]
Downstream 1 [degC]
Downstream 2 [degC]
9/6/2016
22.1
24.3
24.6
9/7/2016
22.3
23.5
24.2
9/8/2016
22.7
24.7
24.5
9/12/2016
23.6
24.8
24.6
9/13/2016
23.1
24.8
24.8
9/14/2016
23.8
25.3
25.4
9/19/2016
24.3
25.8
25.9
9/20/2016
23.8
24.7
24.5
9/21/2016
23.1
24
24.1
9/26/2016
22.6
24.3
24.3
9/27/2016
22.6
22.9
22.9
9/28/2016
22.5
24
23.5
10/3/2016
19.7
22.6
22.5
10/12/2016
15.2
17.1
16.9
10/18/2016
17.5
19.9
21.2
10/25/2016
13.7
17.7
17.4
10/31/2016
16.4
20.8
20.2
11/7/2016
12.3
18.9
16.9
11/14/2016
11.2
18.1
16.3
11 /21 /2016
8.2
15.6
13.6
11/28/2016
9.5
16.4
15.2
12/8/2016
11.4
13.7
12.9
12/14/2016
9.6
14.6
13.3
12/21/2016
6.8
10.6
9.6
12/28/2016
12.7
16.2
15.1
1/5/2017
8.9
10.3
10
1/11/2017
6.8
7.9
7.3
1/18/2017
16.3
18
17.3
1/26/2017
13
13
13.7
1 /31 /2017
7.8
9.3
9.6
2/8/2017
12.4
13.6
14.3
2/16/2017
10.3
10.5
10.4
2/23/2017
15
16.1
17.3
2/28/2017
13.9
16.4
16
3/7/2017
14
14.9
15.4
3/15/2017
6.3
6.6
6.8
3/21/2017
14.2
14.8
13.9
3/29/2017
18.2
18.2
17.9
4/5/2017
17.9
18
18.4
4/11/2017
17
17.7
16.9
4/19/2017
16.7
17.1
17.9
4/27/2017
18.7
18.7
18.9
5/1/2017
21
21.2
21
5/11/2017
19.6
19.7
19.5
5/15/2017
20.4
20.6
19.9
5/24/2017
20.8
20.8
20.6
5/31/2017
21.3
21.8
22.3
6/6/2017
22.3
22.4
22.7
6/7/2017
21.1
20.9
21.1
6/8/2017
20.2
19.9
20.6
6/12/2017
21.2
21.9
22.7
6/13/2017
21.9
22.4
22.8
P1

Instream Temperature Summary NC0085359
Date
Upstream [degC]
Downstream 1 [degC]
Downstream 2 [degC]
6/14/2017
24
23.6
23.5
6/19/2017
23.8
23.8
23.7
6/21/2017
22.6
22.6
22.3
6/22/2017
23.1
23.1
23
6/26/2017
22
22.3
22.8
6/27/2017
21.2
21.5
21.9
6/28/2017
20.6
20.9
20.9
7/3/2017
25
25
24.7
7/5/2017
24.1
24.1
23.9
7/6/2017
24
24
23.9
7/10/2017
23.7
23.8
23.7
7/11/2017
23.7
23.7
23.6
7/12/2017
24.4
24.5
24.3
7/17/2017
23.7
23.9
23.7
7/18/2017
24.1
24.1
24.1
7/19/2017
23.6
23.9
23.7
7/24/2017
24.3
24.2
24.1
7/25/2017
24.8
24.9
24.7
7/26/2017
24.3
24.2
24.1
7/31/2017
21.9
24.1
22.2
8/1/2017
21.5
22.2
22.3
8/2/2017
21.9
23.1
22.8
8/7/2017
23.5
24.1
23.8
8/8/2017
23.3
23.4
23.3
8/9/2017
22.5
22.8
22.4
8/14/2017
24.2
24.3
24.1
8/15/2017
24.4
24.4
24.3
8/16/2017
24.7
24.9
24.6
8/21/2017
26.3
27
26.3
8/23/2017
25.1
25.4
25.1
8/24/2017
23.6
23.9
23.7
8/28/2017
21.5
22.8
22.3
8/29/2017
20.7
22.3
22
8/30/2017
20.7
22.4
21.9
9/6/2017
21.6
22.8
22.7
9/7/2017
19.6
20
19.7
9/8/2017
18.9
19.9
19.9
9/11/2017
18.8
19
18.9
9/13/2017
19.3
19.7
19.4
9/14/2017
20.4
20.5
20.4
9/18/2017
20.9
21.7
21.7
9/19/2017
20.6
21.4
21.6
9/20/2017
20.9
22.2
21.9
9/25/2017
20.8
22
21.9
9/26/2017
21.3
22.7
22.3
9/27/2017
23
24.2
24.1
10/2/2017
17.9
20.6
19.7
10/10/2017
22.8
24.2
24
10/18/2017
15.2
17.9
17.4
10/25/2017
15.1
16.1
16.3
10/30/2017
11.3
16.7
15.1
11/6/2017
17.5
20.7
19.8
P2

Instream Temperature Summary NC0085359
Date
Upstream [degC]
Downstream 1 [degC]
Downstream 2 [degC]
11/14/2017
10.7
12.8
12.6
11/20/2017
10.3
15.6
14.1
11/28/2017
9.3
15.2
13.7
12/4/2017
11.5
15.8
14.9
12/14/2017
8.3
12.4
11.2
12/19/2017
11.8
15.3
14.7
12/27/2017
8.3
10.8
10.1
1/4/2018
2.2
7.3
6
1/10/2018
5.1
10.9
10.8
1/16/2018
5
7.8
6.3
1/22/2018
8
10.9
9.5
2/1/2018
8.6
9.2
9.1
2/6/2018
10
10.1
10.2
2/15/2018
13.3
14.3
14.2
2/21/2018
18.6
17.8
17.7
2/27/2018
13.7
14.2
13.7
3/6/2018
10.6
11.3
11.4
3/14/2018
8.6
9
8.8
3/20/2018
16.3
16.2
16.2
3/27/2018
10.9
11.2
11.3
4/3/2018
17.1
16.8
16.7
4/10/2018
12.9
18.2
13.4
4/18/2018
16.3
17.5
16.4
4/26/2018
18
17.7
17.8
5/1/2018
16
17
16.1
5/8/2018
18.9
20.4
18.9
5/15/2018
22.5
23.2
22.4
5/22/2018
22.4
23.2
22.6
5/29/2018
23.4
23.5
23.5
6/4/2018
24.2
24.3
23.9
6/5/2018
22.2
23.9
22.2
6/6/2018
22.4
23.5
22.4
6/11/2018
25.2
25.7
24.7
6/12/2018
21.8
22.1
22.2
6/13/2018
22.8
23.5
23
6/18/2018
26.5
27.1
26.6
6/19/2018
26.4
26.7
25.8
6/20/2018
27.3
27.6
26.8
6/25/2018
25.8
27.1
25.3
6/26/2018
24.4
25.7
24.3
6/27/2018
24.8
24.8
24.9
7/2/2018
26.1
26.8
26.2
7/3/2018
26.7
28.7
27.3
7/5/2018
26.4
28.1
25.9
7/10/2018
23.8
26.3
24.9
7/11/2018
24.7
27
25.3
7/12/2018
25.4
27
25.9
7/16/2018
24
24.6
24.4
7/17/2018
24.3
24.7
24.5
7/18/2018
24.4
24.7
24.5
7/23/2018
23.4
24.9
23.9
7/24/2018
23.4
23.9
24.5
P3

Instream Temperature Summary NC0085359
Date
Upstream [degC]
Downstream 1 [degC]
Downstream 2 [degC]
7/25/2018
24.8
25
25.5
7/30/2018
25.3
26.2
26.1
7/31/2018
25
25.5
25.4
8/1/2018
24.7
25
25
8/6/2018
25.4
27
26
8/7/2018
25
25.9
25.1
8/8/2018
25.7
26.9
25.8
8/13/2018
24.5
25.2
24.5
8/14/2018
25
26.2
25.8
8/15/2018
25
25.8
25.7
8/20/2018
24.9
25.9
25.6
8/21/2018
24.5
25.5
25.2
8/22/2018
25.1
26.3
25.1
8/27/2018
24.8
26.3
25.4
8/28/2018
25.3
26.2
25.6
8/29/2018
25.5
26.4
25.6
9/4/2018
25.2
26.5
26.4
9/5/2018
25.2
26.5
25.8
9/6/2018
25.5
26.8
26.3
9/10/2018
25.5
26.2
25.2
9/11/2018
23.4
24.5
24.1
9/12/2018
24.3
25.4
24.8
9/19/2018
24
24.2
23.9
9/20/2018
23.8
24.6
23.9
9/21/2018
23.9
24.9
24
9/24/2018
22.3
23.1
22.9
9/25/2018
22.5
23.5
23
9/26/2018
23.3
24.4
23.7
10/1/2018
22.2
23.7
23
10/8/2018
23.4
24.9
24.2
10/16/2018
20.2
21.1
20.9
10/23/2018
13.4
16
15.7
10/29/2018
14.2
15
15.2
11/5/2018
14.8
14.8
14.7
11/14/2018
11.7
11.8
11.8
11/19/2018
12
12.9
12.8
11/26/2018
11.5
12.1
12.2
12/3/2018
15
15.1
15.2
12/13/2018
7.9
7.9
8.7
12/18/2018
9.9
10.6
10.6
12/26/2018
8.6
9.3
9.1
12/31/2018
13.1
13.6
13.6
1/8/2019
12.9
13.5
13
1/15/2019
8.2
9.8
8.9
1/22/2019
5.2
5.8
5.9
1/28/2019
7.4
9.1
8.1
2/4/2019
8.3
10.8
8.9
2/11/2019
8.6
10.1
9.9
2/18/2019
9.6
11
9.9
2/25/2019
10.3
10.6
10.4
3/6/2019
9
8.7
9
3/11/2019
12.7
14.3
12.7
P4

Instream Temperature Summary NC0085359
Date
Upstream [degC]
Downstream 1 [degC]
Downstream 2 [degC]
3/18/2019
11
12.1
11.5
3/25/2019
14.2
15.8
14.1
4/1/2019
13
12.6
13.6
4/8/2019
16.8
17.7
16.6
4/16/2019
15.8
15.9
16.1
4/22/2019
13.8
14.2
14.4
4/29/2019
17.8
18
18.1
5/6/2019
20.5
20.4
20.4
5/13/2019
20.4
20.3
20.4
5/21/2019
21.3
21.3
21.6
5/28/2019
22.9
22.9
23.2
6/3/2019
21.2
21.9
22
6/4/2019
20.7
21.4
21.6
6/5/2019
22.3
22.9
22.5
6/10/2019
23.3
23.3
23.2
6/11/2019
23
23
23.1
6/12/2019
21.1
21.4
21.6
6/17/2019
21.9
22.3
22.6
6/18/2019
23.1
23.3
23.7
6/19/2019
22.9
23.2
23.3
6/24/2019
22.8
23
23.2
6/25/2019
23.2
23.3
23.5
6/26/2019
23.2
23.3
23.5
7/1/2019
24.4
24.5
24.7
7/2/2019
24
24.3
24.5
7/3/2019
24.8
24.8
25.2
7/8/2019
26.6
27.8
26.4
7/9/2019
24.8
25.1
25
7/10/2019
25.2
25.2
25
7/15/2019
25.9
27
25.5
7/16/2019
26.4
28
26.2
7/17/2019
25.9
27.6
25.9
7/22/2019
25.1
25.1
25.2
7/23/2019
24.6
24.7
24.7
7/24/2019
21.6
21.9
21.8
7/29/2019
22.3
23.4
23.5
7/30/2019
22.3
23.6
23.6
7/31/2019
22.5
23.8
23.9
8/5/2019
22.7
23
23
8/6/2019
22.7
23.2
23.6
8/7/2019
23.2
23.9
23.9
8/12/2019
24.1
24.8
25.1
8/13/2019
24.5
25
25.1
8/14/2019
24.1
24.7
24.7
8/19/2019
24.9
25.1
25.3
8/20/2019
24
24.7
24.7
8/21/2019
23.6
23.6
23.5
8/26/2019
21.2
21.7
21.7
8/27/2019
21.2
22.1
22
8/28/2019
22.2
22.8
22.9
9/3/2019
22
23.7
23.6
9/4/2019
22.3
23.8
23.8
P5

Instream Temperature Summary NC0085359
Date
Upstream [degC]
Downstream 1 [degC]
Downstream 2 [degC]
9/5/2019
22.7
24.1
24
9/9/2019
22.8
24.2
24.1
9/10/2019
23.6
24.8
24.9
9/11/2019
24
25.1
25
9/16/2019
22.3
23.1
23
9/17/2019
22.7
23.5
23.7
9/18/2019
22
23.2
23.1
9/23/2019
20
22.5
22.2
9/24/2019
20.6
23
22.7
9/25/2019
20.5
22.6
22.3
10/1/2019
23.3
24.6
24.5
10/7/2019
19.9
22.5
21.9
10/15/2019
16.9
20.2
19.4
10/21/2019
15.8
16.7
16.7
10/28/2019
16.9
17.8
18.1
11/4/2019
10.6
15.1
14.6
11/12/2019
10.5
13.7
13.8
11/18/2019
9
11.9
12
11/25/2019
10.2
11.3
11.5
12/2/2019
11.1
11.9
12.1
12/9/2019
8
11.4
11.7
12/16/2019
10.9
10.6
9.6
12/26/2019
8.5
8.8
9.1
12/30/2019
14.3
14.6
14.8
1/6/2020
9.1
9.4
9.7
1/13/2020
15.1
15
15.4
1 /21 /2020
5.3
6.8
7.3
1/27/2020
8.4
8.8
9.3
2/3/2020
8.9
9.3
9.6
2/10/2020
10.7
9.6
9.9
2/17/2020
9.9
10.4
10.6
2/24/2020
9.4
10.1
10.5
3/3/2020
11.9
12.6
12.7
3/9/2020
11
11
11
3/16/2020
14.2
14.7
14.9
3/23/2020
15
8
15.9
3/30/2020
19
19.3
19.6
4/6/2020
17.2
17
17.3
4/14/2020
17.6
17.8
17.9
4/20/2020
9.1
15
15.1
4/27/2020
15.5
16.1
16.5
5/4/2020
18.7
18.6
18.5
5/11/2020
14.1
14.6
14.9
5/18/2020
19.3
19.8
20
5/26/2020
20.1
20.1
20.2
6/1/2020
19.7
19.9
19.8
6/2/2020
19.2
19.2
19.4
6/3/2020
20.3
20.2
20.5
6/8/2020
23.4
23.2
23
6/9/2020
23.7
23.5
23.6
6/10/2020
23.8
26.6
23.6
6/15/2020
20.2
20.7
20.9
P6

Instream Temperature Summary NC0085359
Date
Upstream [degC]
Downstream 1 [degC]
Downstream 2 [degC]
6/16/2020
18.3
19
19.1
6/17/2020
18.1
18.6
18.8
6/22/2020
22.1
22.2
22.5
6/23/2020
22.6
22.6
22.8
6/24/2020
22.5
22.6
22.7
6/29/2020
23
23.1
23.3
6/30/2020
23.5
24.3
23.7
7/1/2020
23
23
22.9
7/6/2020
23.6
23.7
23.9
7/7/2020
23.3
23.5
23.6
7/8/2020
23.2
23.4
23.5
7/13/2020
24.1
24.2
24.4
7/14/2020
24
24.2
24.3
7/15/2020
25.2
25.1
25.4
7/20/2020
25.6
25.4
25.6
7/21/2020
25.1
25
25
7/22/2020
24.7
24.5
24.4
7/27/2020
24.8
24.8
24.8
7/28/2020
25.2
25.2
25.4
7/29/2020
25.3
25.3
25.3
8/3/2020
25.3
25.3
25.4
8/4/2020
24.4
24.3
24.1
8/5/2020
24.3
24.4
24.3
8/10/2020
24.2
24.4
24.2
8/11/2020
23.6
24.4
24.2
8/12/2020
24.3
24.8
24.8
8/17/2020
23.4
23.6
23.5
8/18/2020
23.3
23.5
23.5
8/19/2020
23.4
23.8
23.8
8/24/2020
23.5
23.8
23.7
8/25/2020
23.5
23.9
23.8
8/26/2020
23.7
24.1
24
8/31/2020
24.4
24.8
24.8
Average
19.4
20.4
20.1
Max
27.3
28.7
27.3
Min
2.2
5.8
5.9
p-value
<
.05
>
.05
P7
Note: Student's t-tests run to compare both downtream locations to the upstream sample location.

11/19/20 WQS = 12 ng/L
Facility Name
Twelve Mile Creek WWTP/NC0085359
/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 =
12/12/18
2/6/19
3/18/20
8/5/20
8/3/16
5/10/17
<
<
<
0.89
1
0.2
0.97
1.1
1
No Limit Required
No MMP Required
0.89
0.5
0.5
0.97
1.1
0.5
0.100
7.500
cfs
WQBEL = 12.10 ng/L
47 ng/L
0.9 ng/L - Annual Average for 2018
0.5 ng/L - Annual Average for 2019
0.7 ng/L - Annual Average for 2020
1.1 ng/L - Annual Average for 2016
0.5 ng/L - Annual Average for 2017

Twelve Mile Creek WWTP/NC0085359
Mercury Data Statistics (Method 1631E)
2018
2019
2020
2016
# of Samples
1
1
2
1
Annual Average, ng/L
0.9
0.5
0.7
1.10
Maximum Value, ng/L
0.89
0.50
0.97
1.1
TBEL, ng/L
47
WQBEL, ng/L
12.1
2017
1
0.5
0.5

NH3/TRC WLA Calculations
Facility: Twelve Mile Creek WWTP
PermitNo. NC0085359
Prepared By: Nick Coco
Enter Design Flow (MGD):
Enter s7Q10 (cfs):
Enter w7Q10 (cfs):
7.5
0.1
1.5
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)
0.1
7.5
11.625
17.0
0
99.15
17
UV used. No limit set.
Ammonia (Summer)
Monthly Average Limit (mg NH3-N/I)
s7Q10 (CFS) 0.1
DESIGN FLOW (MGD) 7.5
DESIGN FLOW (CFS) 11.625
STREAM STD (MG/L) 1.0
Upstream Bkgd (mg/I) 0.22
IWC (%) 99.15
Allowable Conc. (mg/I) 1.0
Same as current permit 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)
1.01 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
1.5
7.5
11.625
1.8
0.22
88.57
2.0
Same as current permit 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)

NH3/TRC WLA Calculations
Facility: Twelve Mile Creek WWTP
PermitNo. NC0085359
Prepared By: Nick Coco
Enter Design Flow (MGD): 9
Enter s7Q10 (cfs): 0.1
Enter w7Q10 (cfs): 1.5
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)
0.1
9
13.95
17.0
0
99.29
17
UV used. No limit set.
Ammonia (Summer)
Monthly Average Limit (mg NH3-N/I)
s7Q10 (CFS) 0.1
DESIGN FLOW (MGD) 9
DESIGN FLOW (CFS) 13.95
STREAM STD (MG/L) 1.0
Upstream Bkgd (mg/I) 0.22
IWC (%) 99.29
Allowable Conc. (mg/I) 1.0
Same as current permit 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)
1.01 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
1.5
9
13.95
1.8
0.22
90.29
2.0
Same as current permit 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)

NH3/TRC WLA Calculations
Facility: Twelve Mile Creek WWTP
PermitNo. NC0085359
Prepared By: Nick Coco
Enter Design Flow (MGD):
Enter s7Q10 (cfs):
Enter w7Q10 (cfs):
12
0.1
1.5
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)
0.1
12
18.6
17.0
0
99.47
17
UV used. No limit set.
Ammonia (Summer)
Monthly Average Limit (mg NH3-N/I)
s7Q10 (CFS) 0.1
DESIGN FLOW (MGD) 12
DESIGN FLOW (CFS) 18.6
STREAM STD (MG/L) 1.0
Upstream Bkgd (mg/I) 0.22
IWC (%) 99.47
Allowable Conc. (mg/I) 1.0
Same as current permit 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)
1.01 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
1.5
12
18.6
1.8
0.22
92.54
1.9
Same as current permit 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)

Reduction in Frequency Evalaution
Facility:
Twelve Mile Creek WWTP
Permit No.
NC0085359
Review period (use
3 yrs)
9/2017 9/2020
Approval Criteria:
Y/N?
1. Not currently under SOS
Y
2. Not on EPA Quarterly noncompliance
report
Y
3. Facility or employees convicted of CWA
violations
N
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%
WA
# daily
samples
>200%
< 20?
# of non -
monthly
limit
violations
> 2?
# civil penalty
asessment
> 1?
Reduce
Frequency?
(Yes/No)
BOD (summer)
mg/L
7.5
5
2.5
2.6406818
N
10
1
Y
0
N
0
N
N
BOD (winter)
mg/L
15
10
5
2.3989899
Y
20
1
Y
0
N
0
N
Y
TSS
mg/L
45
30
15
2.8867388
Y
60
0
Y
0
N
0
N
Y
Ammonia (summer)
mg/L
3
1
0.5
0.1341203
Y
2
3
Y
0
N
0
N
Y
Ammonia (winter)
mg/L
5.7
1.9
1
0.1081605
Y
3.8
0
Y
0
N
0
N
Y
FecalColiform
#/100
400
200
100
4.6058885
Y
800
8
Y
2
N
0
N
Y

MONITORING REPORT(MR) VIOLATIONS for:
Report Date: 10/07/2C Page 1 of 1
Permit: NC0085359 MRs Betweel 9 - 2016 and 9 - 2020
Facility Name: % Param Name%
Major Minor: %
Region:
County: %
Violation Category:Limit Violation
Subbasin:%
Program Category:
Violation Action: %
PERMIT: NC0085359
FACILITY: Union County - Twelve Mile Creek WWTP
COUNTY: Union
REGION: Mooresville
Limit Violation
MONITORING OUTFACE
REPORT
LOCATION
PARAMETER
VIOLATION UNIT OF
DATE FREQUENCY MEASURE
LIMIT
CALCULATED
VALUE
ok
Over
VIOLATION TYPE VIOLATION ACTION
11-2018 001
Effluent
01-2019 001 Effluent
Coliform, Fecal MF, MFC
Broth, 44.5 C
Coliform, Fecal MF, MFC
Broth, 44.5 C
11/17/18 2 X week
01/05/19 2 X week
#/100m1 400 3,422.96 755.7 Weekly Geometric Mean
Exceeded
#/100m1 400 425.35 6.3 Weekly Geometric Mean
Exceeded
Proceed to NOV
Proceed to NOD

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 2 I5 �-I 3 I NC0085359 111 121 20/10/01 117
Type
18 [ = i
Inspector Fac Type
19 i G I 201
21111111iillliliiiIIiiillliilIliiiIlliiiiiiii
166
Inspection Work Days Facility Self -Monitoring Evaluation Rating B1 QA Reserved
671I 70I3 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)
Twelve Mile Creek WWTP
8299 Kensington Dr
Waxhaw NC 28173
Entry Time/Date
10:OOAM 20/10/01
Permit Effective Date
15/01/01
Exit Time/Date
01:07PM 20/10/01
Permit Expiration Date
19/12/31
Name(s) of Onsite Representative(s)/Titles(s)/Phone and Fax Number(s)
///
Jonathan Brian Jordan/ORC/704-562-4542/
Other Facility Data
Name, Address of Responsible Official/Title/Phone and Fax Number
Contacted
Bart Farmer,4600 Goldmine Rd Monroe NC 28110/Water Reclamation Facilities
Superintendant/704-296-4227/7042897395 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
Roberto Scheller DWR/MRO WQ/252-946-6481/
Signature of Management Q A Reviewer Agency/Office/Phone and Fax Numbers Date
W. Corey Basinger DWR/Division of Water Quality/704-235-2194/
EPA Form 3560-3 (Rev 9-94) Previous editions are obsolete.
Page# 1

31
NPDES yr/mo/day
NC0085359 111 121 20/10/01
117
Inspection Type
18 [j
1
Section D: Summary of Finding/Comments (Attach additional sheets of narrative and checklists as necessary)
Facility appeared to be very well operated and maintained; however, one deficiency was noted during
review of Record Keeping. Transported Chain -of -Custody's (COC's) forms were not all avalible on -site
for review and/or signed by laboratory as received.
Page# 2

Permit: NC0085359
Inspection Date: 10/01/2020
Owner - Facility: Twelve Mile Creek VVVVTP
Inspection Type: Compliance Evaluation
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: Facility operating under old permit that expired on December 31, 2019. Renewal application
was received by the Division on July 5, 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?
Facility has copy of previous year's Annual Report on file for review?
Yes No NA NE
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Page# 3

Permit: NC0085359
Inspection Date: 10/01/2020
Owner - Facility: Twelve Mile Creek VVVVTP
Inspection Type: Compliance Evaluation
Record Keeping Yes No NA NE
Comment: At time of inspection Chain -of -Custody (COC) forms were not complete, signed off by
laboratory as received, and not being stored on -site. Please be advised that in accordance
with your NPDES Permit # NC0085359, Part II, Section D, Monitoring and Reporting, For
each measurement or sample taken prusuant to the requirements of this permit, the
Permittee shall record the date, exact place and time of sampling or measurements, and
have access to a copy (hard copy or electronic) of any record that must be kept under the
conditions of the permit.
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:
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 SCADAtelemetry available and operational?
Is audible and visual alarm available and operational?
Comment:
Chemical Feed
Is containment adequate?
Is storage adequate?
Are backup pumps available?
Is the site free of excessive leaking?
Comment: Alkalinity is being added in the form of lime at the head of WWTP.
Yes No NA NE
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Yes No NA NE
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Yes No NA NE
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Page# 4

Permit: NC0085359
Inspection Date: 10/01/2020
Owner - Facility: Twelve Mile Creek VVVVTP
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?
Yes No NA NE
•
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• ❑ ❑ ❑
• ❑ ❑ ❑
Comment: ORC indicated that performance evaluation of qrit removal shows that qrit removal may be
removinq too much orqanic material alonq with qrit.
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?
Yes No NA NE
• ❑ ❑ ❑
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• ❑ ❑ ❑
• ❑ ❑ ❑
Comment: Flow meters are calibrated every 6 months. Influent flow meter was last calibrated on
8/28/2020 by CITI.
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: At time of inspection influent sampler was recorded at 4 degrees Celsius.
Yes No NA NE
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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? ❑ ❑ ❑ ❑
Comment: Facility has 4 treatment trains with an anoxic zone at the head of each train. Facility can alsc
add Sodium Aluminate to aid in Phosphorous removal.
Page# 5

Permit: NC0085359
Inspection Date: 10/01/2020
Owner - Facility: Twelve Mile Creek VVVVTP
Inspection Type: Compliance Evaluation
Nutrient Removal 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:
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: Sludge blanket measured at < 1 foot.
Pumps-RAS-WAS
Are pumps in place?
Are pumps operational?
Are there adequate spare parts and supplies on site?
Comment:
Yes No NA NE
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Yes No NA NE
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Page# 6

Permit: NC0085359
Inspection Date: 10/01/2020
Owner - Facility: Twelve Mile Creek VVVVTP
Inspection Type: Compliance Evaluation
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:
Yes No NA NE
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Filtration (High Rate Tertiary) Yes No NA NE
Type of operation: Cross flow
Is the filter media present? • ❑ ❑ ❑
Is the filter surface free of clogging? • ❑ ❑ ❑
Is the filter free of growth? • ❑ ❑ ❑
Is the air scour operational? • ❑ ❑ ❑
Is the scouring acceptable? ❑ ❑ ❑ •
Is the clear well free of excessive solids and filter media? ❑ ❑ • ❑
Comment: Facility has fabric covered drum filters. One set of filters were in backwash mode at time of
inspection.
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?
Yes No NA NE
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Comment: At time of inspection it was noted that alga was sluffing off from discharge weirs of UV unit. 11
is recommended that weirs be covered from sunlight to prevent a high TSS reading in
effluent samples.
Effluent Sampling
Is composite sampling flow proportional?
Is sample collected below all treatment units?
Is proper volume collected?
Is the tubing clean?
Yes No NA NE
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Page# 7

Permit: NC0085359
Inspection Date: 10/01/2020
Owner - Facility: Twelve Mile Creek VVVVTP
Inspection Type: Compliance Evaluation
Effluent Sampling
# 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)?
Yes No NA NE
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Comment: At time of inspection effluent sampler was recorded at 2.8 degrees Celsius.
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?
Yes No NA NE
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Comment: Flow meters calibrated every 6 months. Effluent flow meter was last calibrated on 8/28/2020
by CITI.
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:
Yes No NA NE
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Page# 8

Whole Effluent Toxicity Testing and Self Monitoring Summary
Unifi-Kinston LLC(EI Dupont) NC0003760/001 County: Lenoir Region: WARO Basin: NEU05 Jan Apr Jul Oct
Ceri7dPF Begin: 4/1/2010 CHR LIM: 1.9% NonComp: SINGLE 7Q10: 283.1 PF: 3.6 IWC: 1.9 Freq: Q
SOC JOC:
J F M A M J J A 5 0 N D
2016 Pass - - Pass - - Pass - - Pass -
2017 Pass - - Pass - - Pass - - Pass -
2018 Pass - - Pass - - Pass - - Pass -
2019 Pass - - Pass - - Pass - - Pass -
2020 Pass - - Pass - - Pass - - -
Unimin Corp. Red Hill Plant NC0085839/001 County: Mitchell Region: ARO Basin: FRB06 Jan Apr Jul Oct
Ceri7dPF Begin: 7/1/2018 chr lim: 3.3% @ 2 M NonComp: Single 7Q10: 90.7 PF: 2 IWC: 1.2 Freq: Q
SOC_JOC:
J F M A M J J A 5 0 N D
2016 Pass - - Pass - - Pass - - Pass -
2017 Pass - - Pass - - Pass - - Pass -
2018 Pass - - Pass - - Pass - - Pass -
2019 Pass - - Pass - - Pass - - Pass -
2020 Fail 4.7 2.3 8.086 (P) Pass - - 4.7 - - -
Unimin Corp. -Crystal Operation NC0084620/001 County: Mitchell Region: ARO Basin: FRB06 Jan Apr Jul Oct
Ceri7dPF Begin: 6/1/2012 chr lim: 2.0% @ 0.55 NonComp: Single 7Q10: 41 PF: 0.553 IWC: 1.3 Freq: Q
SOC JOC:
J F M A M J J A 5 0 N D
2016 >8 - - >8 - - >8 - - >8 -
2017 >8 - - >8 - - >8 - - >8 Pass -
2018 Pass - - Pass - - Pass - - Pass -
2019 Pass - - Pass - - Pass - - Pass -
2020 Pass - - Pass - - Pass - - -
Unimin -Schoolhouse (Mica) NC0000361/001
Ceri7dPF Begin: 6/1/2012 chr lim: 10%
County: Avery
NonComp: Single
Region: ARO
7010: 30
Basin: FRB06 Feb May Aug Nov
PF: 2.6 IWC: 10 Freq: Q
SOC_JOC:
J F M A M J J A 5 0 N
2016 - Pass - - Pass - - Pass - - Pass
2017 - Pass - - Pass - - Pass - - Pass
2018 - Pass - - Pass - - Pass - - Pass
2019 - Pass - - Pass - - Pass - - Pass
2020 - Pass - - Pass - - Pass - -
Union County-12 Mile Creek WWTP NC0085359/001 County: Union Region: MRO Basin: CTB38 Feb May Aug Nov
Ceri7dPF Begin: 1/1/2015 chr lim: 90% (for 6, 9, NonComp: Single 7Q10: 0.0 PF: 6.0 IWC: 100 Freq: Q
SOC_JOC:
J F M A M J J A 5 0 N
2016 - Pass - - Pass >100(P) - - Pass - - Pass
2017 - Pass - - Pass - - >100(P) Pass - - Pass
2018 - >100(P) Pass - - Pass - - Pass - - Pass
2019 - Pass - - Pass - - Pass - - >100(P) Pass
2020 - Pass - - >100(P) Pass - - - -
Legend: P= Fathead minnow (Pimnhales nromelas), H=No Flow (facility is active), s = Split test between Certified Labs
Page 113 of 121