NC0089915_Draft Fact Sheet_20200212 (3)

Fact Sheet
NPDES Permit No. NCOO89915
Permit Writer/Email Contact: [e-mail]
Date: February 12, 2020
Division/Branch: NC Division of Water Resources / NPDES Complex Permitting
Fact Sheet Template: Version 09Jan2017
Permitting Action:
❑ Renewal
❑ Renewal with Expansion
® New Discharge
❑ Modification (Fact Sheet should be tailored to mod
Note: A complete application should include the followi
• For New Dischargers, EPA Form 2A or 2D requirements, Enginee
• For Existing Dischargers (POTW), EPA Form 2A, 3 effluent polluta
tests.
• For Existing Dischargers (Non-POTW), EPA Form 2C with correct
on industry category.
Complete applicable sections below. If not applicable, enter NA.
1. Basic Facility Information
atives Analysis, Fee
4 2°d species WET
based
Facility Information
Applicant/Facility Name:
The Chemours Company / Chemours Fayetteville Works
Applicant Address:
1007 Market Street, Wilmington, DE 19899
Facility Address:
22828 NC Highway 87 W, Fayetteville, NC 28306-7332
Permitted Flow:
1.58 MGD
Facility Type/Waste:
MAJOR Industrial
Facility Class:
II
Treatment Units:
influent oxidation, coagulation, and pH adjustment, ultrafiltration,
granular activated carbon (GAC) adsorption
Pretreatment Program (Y/N):
N/A
County:
Bladen
Region:
Fayetteville
Page 1 of 18
Commented [KC1]: Grade II physical/chemical, per
15A NCAC 08G .0306

Briefly describe the proposed permitting action and facility background.
A. Introduction / Permitting Action
In order to reduce PFAS loading to the Cape Fear River pursuant to the Consent Order entered by the
Bladen County Superior Court on February 25, 2019 ("Consent Order"), Chemours has requested a new
NPDES permit for the discharge of treated groundwater and surface water from a stream located on the
southern portion of its property. The flow from Outfall 003 consists primarily of contaminated groundwater
and surface water, which must be treated to remove at least 99% of the PFAS. This stream, often referred
to as "Old Outfall 002," was used to discharge process wastewater from the facility prior to June 2012,
when Outfall 002 was relocated to the current outfall location (for permit NC0003573) above Lock and
Dam #3 (also known as William O Huske Dam) in the Cape Fear r. Pursuant to the Consent Order,
Chemours is required to implement a system to capture and treaythe weather flow at Old Outfall 002
prior to discharge by September 30, 2020. The treatment system shall meet such discharge standards as
shall be set by DEQ, and shall, in addition and at a miniyalum, be at.least 99% effective in controlling
indicator parameters, GenX and PFMOAA, i.e. 99% removal of these parameters. The issuance of this
permit will allow Chemours to begin this remediatio et the Cons\aoad
ent and reduce
PFAS loading to the Cape Fear River.
Additionally, as part of the Consent Order, Chemou required to conng Assessment.
The summary report was submittedto DEQ on Dece er 6, 20]�. Thel the sources of
per- and polyfluoroalkyl substances (PFAS) on and around the elite and tloadings to the
Cape Fear River. Chemours estimates that remediating the baseflow (groundwater and surface water) from
this channel will reduce overall loading of Total Table 3+ PFAS compounds to the river by 26% (Cape Fear
River PFAS Loading Reduction Plan — Supplemental Information rt, November 2019).
This outfall is named Outfit �' this new permit to allow-1 the pot 'al consolidation of Chemours
other NPDES wastew ter permit 03573, in
B. Proposed Treatment System
The proposed treatment system inclu es a am to collect ry weather baseflow estimated to be 540
gallons per minute) and,some seep and groundwater, for a total flow capacity of the dam of 610 gallons
per minute (gpm). The treatment system is designed to treat a maximum flow of 750 gallons per minute
(gpm), w h will allow for treatment of the dry weather flow from the Old Outfall 002 channel and
additional cont a mated water from seeps oundwater from elsewhere on -site.
The system is exp d to be able to remove numerous PFAS compounds, including the indicator
parameters HFPO-DA (GenX) and PFMOAA. Again, the Consent Order specifies that HFPO-DA and
PFMOAA are to be rex loved from the Old Outfall 002 channel by at least 99%. The Consent Order
required Chemours to compete, at a minimum, monthly surface water sampling in Old Outfall 002 at
designated locations, beginning no later than March 2019 to be completed by September 30, 2019 to
establish baseline mass loading from Old Outfall 002. Additionally, by September 30, 2019, Chemours
was required to complete pilot scale testing of treatment equipment to determine its control efficiency for
all PFAS identified in Old Outfall 002. Pilot testing results, received by DWR on October 3, 2019,
demonstrated that the proposed granular activated carbon (GAC) system can remove at least 99% of the
total PFAS compounds reported per the Consent Order.
This proposed treatment system will consist of the following components:
1) Influent Oxidation, Coagulation & pH Adjustment
This treatment system includes an influent oxidation/coagulation /pH adjustment tank for pretreatment of
the ultrafiltration (UF) feed (pH adjustment/oxidation/coagulation). The pH adjustment will be done using
Page 2 of 18

sodium hydroxide. Additional iron oxidation will be done with sodium hypochlorite. Poly -aluminum
chloride (PAC) will be used for coagulation and contribute to help maintain the OF membranes. Partially
treated water will be conveyed to the OF units via dual booster pumps. Safety Data Sheets (SDSs) are
attached for the chemicals to be utilized at the wastewater treatment system.
Iron hydroxide particles precipitated in the oxidation process and total suspended solids (TSS) will be
coagulated and settled in the tank. The settled solids will be transferred by a solids transfer pump to a weir
tank (back pulse waste recycle tank) and filtered in downstream removal processes (thickener and rotary -
fan filter press).
2) Ultrafiltration
This design includes OF pretreatment before the Granular Activated Carbon (GAC) stage. The OF will
perform the role of solids removal upstream of the GAC units. The will provide an absolute barrier to
solids at 0.04 - 0.1 µm range. Per the manufacturing vendor, the me rane will provide additional TOC
removal as well.
The OF back pulse waste recycle will be captured in a weil4ank to allow solids to settle and then will be
recycled through the system after being pumped back tope uentidation/coagulation /pH adjustment
tank. The settled solids in the weir tank (the back-pul5� waste recycle tank) will be drawn off by a sludge
pump and filtered in downstream removal processes (thickener and rotary -fan filter press).
The OF units will intermittently need to be clearil with a low co entration of c c acid. The cleaning
solution will be captured in a Clean -In Place (CIP) tank and neutraliz in it. Follo eutralization, the
CEP water will be recycled through th tment system after being pumped back b neutralization
pumps to the influent oxidation/coagulation /pFVadjustment to
3) Granular Activated Carbon (GAC) Adsorption
Based on GAC adsorption studies, PEAS removal to meet disc\rements (per the CO), is expected
to be accomplished using GAC adsorption. The system designation includes a total of six (6)
12' diameter x 5' diameter straight de vessels in a three (3) pass configuration capable of swapping
lead/middle/lag. Each GAC vessel ca old up to 20,000 lbs. of GAC? The GAC beds will be sluiced out
upon exhaustion and th ew bed sluiced back into the vessel. The GAC vessels have backwashing
capability. SiWquantitie d config may b dified during process optimization.
4) Solling and Treatment
The treatment system includes a containerized slu dling system with sludge pump, polymer make
down/injNtion system, in -line mixer and a thickener unit and rotary fan press skid. The rotary fan press
will be moun on a sump with a pump to re filtrate from the process to the head of the plant into the
influent oxida agulation /pH adjustment . Additionally, the solids handling system will include
a screw conveyoilwmove the sludg out of the container/press and into a roll off for storage, until the
sludge accumulates enou h to be led off site. Solid waste is to be shipped to a Waste Management
Landfill in Emelle, AL.
5) Discharge
The treated water will be discharged and reintroduced to Outfall 003. The discharge location will be in the
Cape Fear River, downstream of the capture dam.
C. Facility Background
Currently, no process wastewater from Chemours is discharged. The only process wastewater discharged
comes from Chemours' tenants DuPont and Kuraray. That wastewater is covered under the NPDES
discharge permit #NC0003573. This permit HNC0089915 is for the collection and treatment of the
contaminated dry weather flow (groundwater and surface water) in Chemours old Outfall 002 channel.
Renewal of permit NC0003573 will be addressed separately from this permit.
Page 3 of 18

2. Receiving Waterbody Information
Receiving Waterbody Information
Outfalls/Receiving Stream(s):
Outfall 003 — Cape Fear River
Stream Segment:
18-(2625)
Stream Classification:
C, WS-Iv
Drainage Area (mi'):
4852
Summer 7Q10 (cfs):
467 (17.14 —used in limit calculations to account for dilution,
the number is based on the odeling)
Winter 7Q10 (cfs):
603
30Q2 (cfs):
900
Average Flow (cfs):
4220
12.5% (based on th odel)
IWC (% effluent):
303(d) listed/parameter:
No, the segment is not listed on the 2018 303(d) list
Subject to TMDL/parameter:
Yes — State-wide Mercury L implementation.
Sub-basinMUC:
Outfall 002: 03-06-16 /
USGS Topo Quad:
Duart lk
3. Effluent Data Summary
N/A — N Di harge
This is a new p or the colle and trea ent of contaminated dry weather flow in a channel leading to
the Cape Fear Rive viously, ours used this channel to discharge process wastewater and referred to
it as "Old Outfall 002
4. Instream Data
Instream monitoring may be required in certain situations, for example: 1) to verify model predictions
when model results for instream DO are within 1 mg/l of instream standard at full permitted flow; 2) to
verify model predictions for outfall diffuser; 3) to provide data for fixture TMDL; 4) based on other
instream concerns. Instream monitoring may be conducted by the Pennittee, and there are also
Monitoring Coalitions established in several basins that conduct instream sampling for the Pennittee (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: As part of the Consent Order (Paragraph I I (d)), Chemours is required to sample its intake,
discharge (Outfall 002), and a multitude of additional on -site locations for PFAS compounds. These
Page 4 of 18

sampling efforts are detailed in the Updated PEAS Characterization Plan, dated May 1, 2019. This plan
and the sampling locations were conditionally approved by DWR on June 19, 2019.
Chemours' existing NPDES permit, NC0003573, has instream monitoring requirements for temperature,
dissolved oxygen, and conductivity on a weekly basis to evaluate the effects of its discharge on the
receiving stream. Chemours is a member of the Middle Cape Fear Basin Association, with upstream
coalition station B8290000 (approximately 1 mile upstream of Outfall 002) and downstream coalition
station B8302000 (approximately 4 miles downstream of Outfall 002), instream monitoring for PEAS
compounds will be required.
Is this facility a member of a Monitoring Coalition with waived instream monitoring (Y/N): Y
Name of Monitoring Coalition: Middle Cape Fear Basin Associate
5. Compliance Summary
Summarize the compliance record with permit effluent tits (past 5 years s is a new permit.
Summarize the compliance record with aquatic toxicity test limits and any secoNpe
test results
(past S years): This is a new permit.
Summarize the results from the most r mpliance inspecti This is a n
6. Water Quality -Base ffluent Limitations WQBELs
Dilution and Mixing Zones
In accordance with ANCAC 213.0206, the following stream flows are used for dilution considerations
for development of WQBELs: 1Q10 streamflow (acute Aquatic Life); 7QI0 streamflow (chronic Aquatic
Life; non -carcinogen HH); 30Q2 streamflow (aesthetics); annual average flow (carcinogen, HH).
If applicable, describe any other dilution factors considered (e.g., based on CORMIX model results):
Geosyntee,Consultants of NC has submitted CORMIX model results on behalf of The Chemours
Company FCSaden
r the primary discharge Outfall 002 of their Fayetteville Works site discharging to
the Cape Fealassified W`S-IV, approxiately 1,500 feet above the William O Huske Dam aka
Lock and DaCounty. The discharge was modeled because of concerns over incomplete
mixing due to the presence of the lock and dam system and background concentrations from site runoff,
aerial deposition, seepage, and groundwater flow containing per -and polyfluoralkyl substances (PEAS)
into the river.
The CORMIX model river schematization used The Army Corps of Engineers 2016 bathymetric survey
data which showed a consistent river cross-section profile from the point of discharge to just above Lock
and Dam 3. Critical river flows were obtained from the USGS in June 2019, which showed a marked
decrease in critical flow statistics from those used in prior permits. The lower flows reflect changes in the
B. Everett Jordan Lake Drought Contingency Plan formally approved in 2008 and operationally in effect
since 2007. Water levels in the model were determined from the continuous record USGS stream gage
(Station 02105500) located at the lock and dam. Outfall parameters in the model were based on the
existing outfall configuration.
Page 5 of 18

The modeled pollutant of concern is HFPO-DA at a concentration of 710 ng/L. The final model results
predict the NC Department of Health and Human Services HFPO-DA health goal of 140 ng/L is met at
15.8 meters from the outfall. Mixing continues till 21.2 in from the outfall where the plume begins to
exhibit passive ambient diffusion with little additional dilution. At this point the effluent plume dilution is
8:1 until model end. Though model results indicate the NC DIMS provisional health goal is met,
additional onsite and downstream loading of the target compound is not accounted for in the model and
the dilution model should not be used to establish final water quality -based effluent limitations. The
model results can be used, however, to establish dilution based effluent limitations for parameters with
little to no background concentrations. The 8:1 dilution is both more conservative than and supported over
instream waste concentration (IWC) based limitations normally performed under 15A NCAC 2B. The
IWC from using standard procedures under 7Q10 flow conditions of 7 cubic feet per second (cfs)
would be 9% versus 12.5% at an 8:1 dilution. The 8:1 dilution fa tor, deled and established for
Chemours upstream discharge at Outfall 002 was used as a cons4rvative estimate to assess effluent limits
and monitoring requirements for the discharge (Outfall 003 this p it.
Applying EPA criteria for sizing mixing zones in their ical Supp cument for Water Quality -
based Toxics Control 1991 section 4.3.2, with the st iting facN
ute mixing zone
based on 10% of the size of the regulatory mixing'e, an 8:1 chroat 21.2 m would
result in an acute mixing zone with a dilution of 2.3. at 2.1 m fro
It should be noted, that the model produ an effective summer 7 7.14 cfs. This is
a very conservative assumption, as it i tiallylower than f 4 .0 cfs for the
7Q10s. Because the CORMLY model pr high level of protection for the receiving stream and
the downstream water users, the effective Os used in th asonable Potential Analysis (RPA)
for Outfall 003.
If applicable, describe any mixing zonis
established in accordance with 1 SA NCAC 2B.0204(b): N/A.
Oxygen -Consuming Waste Limitation
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.
Ifpermit limi a more stringe an TBE escribe how limits were developed. See "Dilution and
Mixing Zones' on above.
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 ing/I (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 arty proposed changes to ammonia and/or TRC limits for this permit renewal: The facility
conducted a comprehensive evaluation of the dry weather flow in the creek bed (channel) and submitted
results on the EPA Form 2D to the Division. The analysis indicates that there is no ammonia or TRC.
Page 6 of 18

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) stream flows 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 provided by the facility in the
permit application. Pollutants of concern included toxicant
s,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 follo g parameters will receive a water quality -based
effluent limit (WQBEL) since they demonstrated a reasonable potential to exceed applicable
water quality standards/criteria: Silver, Cobalt, Selenium, Mercury.
• Monitoring Only. The following parameters will receive a monitor -only requirement since they
did not demonstrate reasonable potential to exceed applic"a'ble water quality standards/criteria,
but the maximum predicted concentration was >50% of the allowable concentration: Cadmium,
Copper, Cyanide, Lead, Thallium.
• No Limit or Monitoring: The following parameters will not receive a limit or monitoring, since
they did not demons reasonable potential to exceed applicabl4owater quality
standards/criteria and the maximum predicted concentration was <50% of the allowable
concentration: Aluminum, Arsenic, Barium, Beryllium, Cadmium, Total Phenolic Compounds,
Total Chromium, Fluoride, Molybdenum, N el, Sulfate, Zinc, Nitrate/nitrite.
Attached are the RPA results and a copy of the guidance entitled "NPDES Implementation of Instream
Dissolved Metals Standards —Freshwater Standards. "
Toxicity Testing Limitation
Permit limits and monitoring requirements ole Effluent Toxicity (WET) have been established in
accordance with Division guidance (per WET emo, 8/2/1999). Per WET guidance, all NPDES permits
issued to Major facilities, or any facility discharging "complex" wastewater (contains anything other than
domestic waste) will contain appropriate WET limits and monitoring requirements, with several
exceptions. The State has received prior EPA approval to use an Alternative WET Test Procedure in
NPDES permits, using single concentration screening tests, with multiple dilution follow-up upon a test
failure.
Describe proposed toxicity test requirement: This is a Major Industrial facility, and a chronic WET limit
at 12.5% with quarterly frequency is established in the permit.
Mercury Statewide TMDL Evaluation
There is a statewide TMDL for mercury approved by EPA in 2012. The TMDL target was to comply
with EPA's mercury fish tissue criteria (0.3 mg/kg) for human health protection. The TMDL established a
wasteload allocation for point sources of 37 kg/year (81 lb/year), and is applicable to municipals and
Page 7 of 18

industrial facilities with known mercury discharges. Given the small contribution of mercury from point
sources (-2% of total load), the TMDL emphasizes mercury minimization plans (MMPs) for point source
control. Municipal facilities > 2 MGD and discharging quantifiable levels of mercury (>1 ng/1) will
receive an MMP requirement. Industrials are evaluated on a case -by -case basis, depending if mercury is a
pollutant of concern. Effluent limits may also be added if annual average effluent concentrations exceed
the WQBEL value (based on the NC WQS of 12 ng/1) and/or if any individual value exceeds a TBEL
value of 47 ng/l.
Describe proposed permit actions based on mercury evaluation: This is anew permit and the Division
has no historic data to conduct a comprehensive evaluation. The RPA indicates the need for a standard of
96.0 ng/L. However, State Implementation Strategy specifies a Technology Based Effluent Limit for
mercury of 47.0 ng/L. This limit is more stringent than the R4Strateg
fore will be implemented in the
permit.
Other TMDL/Nutnent Management Strategy Considerations
If applicable, describe any other TAMLs/Nutrient Ma emed their implementation
within this permit: N/A. ik
Other WOBEL Considerations
If applicable, describe any other parame,_ers of concern aluated for WQBELs:
The TBELs result in more stringent effluent limits for GenX than result from a calculation of effluent
limits using the dilution model with the health goal of 140 ng/L for GenX.
If applicable, describe any s ecial actions (HQW or ORW) this receiving stream and classification shall
comply with in order to protect t e designated waterbod V'
If applicable, describe any compliance schedules proposed for thi it renewal in accordance with
15A NCAC 2H.0107(c) (2) (B), 40CFR 122.47, and EPA May 2007 Memo.
If applicable, destribe any water quality standards variances proposed in accordance with NCGS 143-
215.3(Ano
d 15A NCAC 2B.0226 for this permit renewal: N/A.
7. Telogy-Based Effluent Limitations (TBELs)
Describe what this facility produces: This i face/groundwater remediation permit for the Chemours
facility that produces organic chemicals.
List the federal effluent limitations guideline (ELG) for this facility: N/A.
If the ELG is based on production or flow, document how the average production/fow value was
calculated: N/A.
For ELG limits, document the calculations used to develop TBEL limits: N/A.
If any limits are based on best professional judgement (BPJ), describe development: N/A.
Document any TBELs that are more stringent than WQBELs: The TBELs for GenX and PFMOAA were
calculated in accordance with the Consent Order, which requires that the treatment system removes 99%
of both compounds.
The calculation was based on the permit application data, which indicates that the influent contains the
following concentrations: GenX— 6.0 µg/L; PFMOAA = 85 µg/L.
Page 8 of 18

The facility provided an Engineering Report on Wastewater Treatability. The Report demonstrated that
the proposed Granular Activated Carbon (GAC) system is able to remove 99% of all PEAS compounds
present in the wastewater. The GAC system showed that when indicator compounds PFMOAA and GenX
are removed at the rate of 99%, the other PEAS identified in the Table 3+ and EPA Method 537 are also
removed at the rate of at least 99%.
The TBELs documented as part of the pilot study of 0.06 µg/L for GenX, and 0.85 µg/L for PFMOAA.
Below please find the limit calculation. The application data indicates that the groundwater that will be
treated by the GAC has the following concentration for two indicator parameters: GenX— 6.0 µg/L;
PFMOAA = 85 µg/L. The results in the application are based on a single 24-hr composite influent
sample. The facility is obligated to remove 99% of the PEAS from fluent. Therefore, the expected
effluent shall be limited as follows:
GenX = (6.0 µg/L/100%) * 1 % = 0.06 µg/L
PFMOAA = (85.0 µg/L/100%) * 1% = 0.85 µg/L
In addition, and as required by the Consent Order the tr ent will be req to demonstrate 99%
removal based on monthly averages which may at times be a more stringent r ment than the limits
cited above.
The Division is unable to calculate W Ls for the ISLA#o the absence o e standards or
EPA criteria for these parameters. hi addition, tgaccurately assess WQBELs, a mass based loading from
all sources should be used to establish a water quality -based wasteload allocation for EFPO-DA and
associated PEAS. When EPA develops PFAS criteria or the State adopts standards for any of the
compounds generated by Che ours, the Division will conduct a reasonable potential analysis and reopen
the permit to include the ne
Ao
1
Document any TBELs that are less stringent X^�!s is a new permit.
AL L
8. Antidegradation Review (New/Ex n in Discharge)
The objective of an antidegradation review is to ensur 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 2E10105(c)(2). In all
cases, existing instream water uses and the level of water quality necessary to protect the existing use is
maintained and protect
If applicable, describe the r f the antidegradation review, including the Engineering Alternatives
Analysis (EAA) and arty water quality modeling results: The facility provided an FAA to justify new
discharge, please see the application for details.
The facility reviewed the following available alternatives: Connection to the Existing Publicly Owned
Treatment Works (POTW), Land Application, Wastewater Reuse in the Facility, Trucking Offsite, and
Direct Discharge.
Connection to the existing POTW was not available since the nearest Rockfish Creek Water Reclamation
Facility refused to accept this wastewater.
Page 9 of 18

The Present Value Costs for the next 20 years was calculated using EPA discount factor of 3.5%, the
Costs are presented below:
Land Application — $86,000,000
Wastewater Reuse in the Facility - $69,600,000 (including riparian restoration)
Trucking Offsite - $8,710,000,000
Direct Discharge- $67,000,000
The Analysis indicates that the direct discharge is the most environmentally sound alternative selected
from all reasonably cost-effective options [per 15A NCAC 2110105(c)(2)].
The Division has given a significant consideration to the fact that ev ith the 99% removal efficiency,
the baseflow treatment system will discharge effluent with GenX tration of 60 ng/L. This
concentration is lower than the state health goal of 140 ng/L.
9. Antibacksliding Review
Sections 402(o)(2) and 303(d)(4) of the CWA and federa regulations at 40 CFR 122.44(1) prohibit
backsliding of effluent limitations in NPDES permits. These provisions requirr 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). IW
Are any effluent limitations less stringent than previous permit (YES/NO): N/A. This is a new permit.
If YES, confirm that antibac ing provisions are not violated: N/A.
10. Monitoring Re ements
Monitoring frequencies for NPDES permitting are established in accordance with the following
regulations and guidance: 1) State Regulation for Surface Water Monitoring, 15A NCAC 2B.0500; 2)
NPDES Guidance, Monitoring Frequency for Toxic Substances (7/15/2010 Memo); 3) NPDES Guidance,
Reduced Monitoring Frequencies for Facilities with Superior Compliance (10/22/2012 Memo); 4) Best
Professional Judgement (BPJ). Per US EPA (Interim Guidance, 1996), monitoring requirements are not
considered effluent limitations under Section 4d2(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 ection 4.
11. Electronic Reporting Requirements
The US EPA NPDES Electronic Reporting Rule was finalized on December 21, 2015. Effective
December 21, 2016, NPDES regulated facilities are required to submit Discharge Monitoring Reports
(DMRs) electronically. Effective December 21, 2020, NPDES regulated facilities will be required to
submit additional NPDES reports electronically. This permit contains the requirements for electronic
reporting, consistent with Federal requirements.
12. Summary of Proposed Permitting Actions
Page 10 of 18

Parameter
Current Permit
Proposed Change
Basis for Condition/Change
Flow
N/A (new permit)
MA 1.58 MGD
15A NCAC 2B .0505
BOD5
N/A (new permit)
MA 30.0 mg/L
WQBEL. Based on protection of DO
DM 45.0 mg/L
standard. 15A NCAC 2B.0200
TSS
N/A (new permit)
MA 30.0 mg/L
TBEL. Secondary treatment
WA 45.0 mg/L
standards/40 CFR 133 / 15A NCAC
2B .0406
Temperature
N/A (new permit)
The ambient
WQBEL. State WQ standard, 15A
temperatur cee
CAC 2B .0200
32°C
DO
N/A (new permit)
WVW
W State WQ standard, 15A
upstream/downstream
NCA 0200
Monitoring Only
HFPO-DA (GenX)
N/A (new permit)
MA 0.06 µg
TBEL, based the Consent Orde ,
DM 0.06 µg/L
Kkk
PFMOAA
N/A (new permit)
MA 0.85 µg/L
TBEL, based on the Consent Order
DM 0.85 µg/Ls,
0
PEAS compounds
N/A new permit
Effluent and Inta
qk
Based on the Consent Order
Monitoring Only
(variable frequencies)
pH
N/A (new permit)
6.0 — 9.0 SU
WQBEL. State WQ standard, 15A
NCAC 2B .0200
Total Nitrogen
N/A (nNN
Monthly Effluent
State WQ Rule, 15A NCAC 2B
Monitoring Only
.0500
Total Phosphorus
N/A (new permit)
Monthly Effluent
State WQ Rule, 15A NCAC 2B
Monitoring Only
.0500
Conductivity
N/A (ne nnit)
Monthly
State WQ Rule, 15A NCAC 2B
upstream/downstream
.0500
Monitoring Only
Toxicity Test
N/A (new permit)
Chronic limit, 12.5%
WQBEL. No toxics in toxic
effluent
amounts. 15A NCAC 2B.0200 and
15A NCAC 2B.0500
Total Hardness
N/A (new permit)
Quarterly Effluent
State WQ standard, 15A NCAC 2B
Monitoring Only
.0200
Page 11 of 18
Commented [KC2]: Add specific CO paragraph
references? i.e. Paragraph 12

Total Selenium
N/A (new permit)
MA 40.0 µg/L
State WQ standard, 15A NCAC 2B
.0200
DM 379.8 µg/L
Total Silver
N/A (new permit)
MA 0.48 µg/L
State WQ standard, 15A NCAC 2B
.0200
DM 2.01 µg/L
Total Cobalt
N/A (new permit)
MA 23.9 µg/L
State WQ standard, 15A NCAC 2B
.0200
DM 23.9 µg/L
Total Cadmium
N/A (new permit)
Quarterly Effluent
State WQ standard, 15A NCAC 2B
Monitoring Only
.0200
Total Copper
N/A (new permit)
Quarterly E
State WQ standard, 15A NCAC 2B
Monito ' y
0200
Total Cyanide
N/A (new permit)
Q Effluent
St Q standard, 15A NCAC 2B
. g Only
.020
Total Lead
N/A (new permit
Quarterl
State WQ st d, 15A NCAC 2B
Ironitoring
.0200
Total Thallium
N/A (new permit)'Quarterly
Effluen
State WQ standard, 15A NCAC 2B
Monitoring Only
.0200
Mercury
N/A (new permit)
Quarterly Effluent
State WQ standard, 15A NCAC 2B
Monitoring Only A
.0200
Electronic
N/A (new pennit)
Required
In accordance with EPA Electronic
Reporting
46
Reporting Rule 2015.
MGD — Million gallons pef day, MA — Monthly Average, DM — Daily Max
13. Public Notice Schedui
Permit to Public Notice: xx/xx/2020
Per 15A NCAC 2H .0109 & .0111, The Division will receive comments for a period of 30 days following
the publication date of the public notice. Any request for a public hearing shall be submitted to the
Director within the 30 days comment period indicating the interest of the party filing such request and the
reasons why a hearing is warranted.
14. NPDES Division Contact
If you have questions regarding any of the above information or on the attached permit, please contact
Sergei Chernikov at [phone] or via email at [e-mail].
15. Fact Sheet Attachments (if applicable)
Page 12 of 18

• RPA Sheets
o Input Sheet
o Data Sheets
o RPA Sheet
o Dissolved to Total Metal Calculator Sheet
• NPDES Implementation of Instream Dissolved Metals Standards— Freshwater Standards
Page 13 of 18

NPDES Implementation of Instream Dissolved Metals Standards - Freshwater Standards
The NC 2007-2015 Water Quality Standard (WQS) Triennial Review was approved by the NC
Environmental Management Commission (EMC) on November 13, 2014. The US EPA subsequently
approved the WQS revisions on April 6, 2016, with some exceptions. Therefore, metal limits in draft permits
out to public notice after April 6, 2016 must be calculated to protect the new standards - as approved.
Table 1. NC Dissolved Metals Water Quality Standards/Aquatic Life Protection
Parameter
Acute FW, µg/1
(Dissolved)
Chronic FW, µg/1
(Dissolved)
Acute SW, µg/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
bioaccumulativ 'concerns (as are allan health standards fot�all metals). It is still
necessary to aluate total recoverable,atic life and human health standards listed in 15A
11
NCAC 213.0200 (e.g., arsenic at 10 µg/l for human health protection; cyanide at 5 µg/L and
fluoride at 1.8 mg/L for aquatic 'fe protection).
Table 2. Disso -Freshwater Standar s r Hardness -Dependent Metals
The Water Effects Ratio (WER) t equal to one unless determined otherwise under
15A NCAC 02B .0211 Subparagraph (11)(d)
Metal
NC Dissolved Standard, µg/l
Cadmium, Acute
WER*{1.136672-[In hardness](0.041838)1 e^{0.9151 [In hardness]-
3.14851
Cadmium, Acute Trout
waters
WER*{1.136672-[In hardness](0.041838)1 e^{0.9151[ln hardness] -
3.62361
Cadmium, Chronic
WER*{1.101672-[In hardness](0.041838)1 e^{0.7998[ln hardness]-
4.44511
Chromium III, Acute
WER*0.316 e^{0.8190[In hardness]+3.72561
Chromium III, Chronic
WER*0.860 e^{0.8190[ln hardness]+0.68481
Copper, Acute
WER*0.960 e^{0.9422[lnhardness]-1.7001
Page 14 of 18

Copper, Chronic
WER*0.960 - e^{0.8545[lnhardness]-1.702}
Lead, Acute
WER*{1.46203-[In hardness](0.145712)} e^{1.273[ln hardness]-
1.460}
Lead, Chronic
WER*{1.46203-[In hardness](0.145712)} e^{1.273[ln hardness]-
4.705}
Nickel, Acute
WER*0.998 e^{0.8460[ln hardness]+2.2551
Nickel, Chronic
WER*0.997 e^{0.8460[lnhardness]+0.0584}
Silver, Acute
WER*0.85 - e^{1.72[ln hardness]-6.59}
Silver, Chronic
Not applicable
Zinc, Acute
WER*0.978 e^{0.8473[ln hardness]+0.8841
Zinc, Chronic
WER*0.986 e^{0.8473[lnhardness]+0.8841
General Information on the Reasonable Potential Analysis (RPA)
The RPA process itself did not change -as the result of the new etals standards. ever,
application of the dissolved and hardness -dependent standard 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 edVMkted case -by -case for each discharge.
Metals limits must b xpressed as `total recoverable' tals in accordance with 40 CFR 122.45(c).
The discharge-specifi tandards must be converted t 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 po consider case-spe 'ftc translators developed in accordance with
establish methodolo
The RPA is designed to predict the maxunum ely effluent concentrations for each metal of concem, based
on recent effluent data, and calculate the allowable effluent concentrations, based on applicable standards and
the critical lowflowvalues .for the receiving stream.
If the maximum predicted
alue is greater than the maximum allowed value (chronic or acute), the
discharge has reasonable po ential 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) ""
• Effluent hardness and upstream hardness, site -specific data is preferred
• Permitted flow
Page 15 of 18

• 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 Tonicity 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. 40*
If the use of a default hardness value results in axdness-de nt metal showing
reasonable potential, the permit writer ntacts the Permittee an nests 5 site -specific
effluent and upstream hardness samples ver a period of one week. RPA is rerun using
the new data.
The overall hardness value use ater quality c ons is calculated as fo ows:
Combined Hardness (chronic)
(Permitted Flow, c * v . Effluent Hardness L + 010 fs *Avo,. Upstream Hardness
(Permitted Flow, cfs + s7Q1 1.1
The Combined dness for acute is the some buthe calculation uses the 1Q10 flow.
3. The pexxnit writer c nverts the numeric standard for each metal of concern to a total
recoverable metal, using the EPA Default Partition Coefficients (F)PCs) 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: Guidancefor Calculating a Total Recoverable
Permit Limit from a Dissolved Criterion (EPA 823-B-96-007, June 1996) and the
equation:
Ctotal 1 + { [Kpo] [SS(1+a)] [10 6] 1
Where:
ss = in -stream suspended solids concentration [mg/1], minimum of 10 mg/L used,
Page 16 of 18

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 Cie.
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 convex on 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 = s7 10 + w Cw s — s7 10
Qu IV
Where: Ca = allowable effluent concentration (ig/L or mg/L)
Cwqs = NC Water Quality Standard or federal criteria (Ng\mg//TL))
Cb = background concentration: ass e zero for all xicants
except NH3* (lig/L or mg/L)
Qw = permitted effluent floNeto
, match s7Q10)
s7Q10 = summer low flow protect aquat c life fro 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
<thef th 10 may eincorporat icable:
Q10 = used in the equation to protect aquatic life from acute toxicity
QA,= used in the equation to otect human health through the consumption of water, fish,
and shellfish from carcinogens
30Q2 — us4in equation to protect aesthetic quality
The permit writer enters the most recent 2-3 years of effluent data for each pollutant of
concern. Data entered must have been taken within four and one-half years prior to the date
of the permit application (40 CFR 122.21). The RPA spreadsheet estimates the 95th
percentile upper concentration of each pollutant. The Predicted Max concentrations are
compared to the Total allowable concentrations to determine if a permit limit is necessary. If
the predicted max exceeds the acute or chronic Total allowable concentrations, the discharge
is considered to show reasonable potential to violate the water quality standard, and a permit
limit (Total allowable concentration) is included in the permit in accordance with the U.S.
EPA Technical Support Document for Water Quality -Based Toxics Control
published in 1991.
Page 17 of 18

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 samp ng, upstream of the discharge, are
inserted into all permits with facilities monitoring for hard ss-dependent metals to ensure
the accuracy of the permit limits and to;buoildorerobes dness dataset.
10. Hardness and flow values used in the Ronable Potential Analysi for this permit included:
Parameter
Value h,
Comments (Data Source
Average Effluent Hardness (mg/L)
Total as, CaCO3 or (Ca+Mg)]
25.
Default v e
Average Upstream Hardness
(mg/L) l%
[Total as, CaCO3 pr (Ca+Mg)]
**4
Default value
%L
7Q10 summer (cfs)
17.14
CORNUX model, 8:1dilution
1 Q10 (cfs)
14.16
RPA calculation
Permitted Flow GD)
.58
Design flow of treatment system
Page 18 of 18