NC0089915_Draft Fact Sheet_20200212 (4)

Fact Sheet
NPDES Permit No. NCO089915
Permit Writer/Email Contact: [e-mail]
Date: February 12, 2020
Division/Branch: NC Division of Water Resources / NPDES Complex Permitting
Fact Sheet Template: Version 09Jan20I7
Permitting Action:
❑ Renewal
❑ Renewal with Expansion
❑X New Discharge
❑ Modification (Fact Sheet should be tailored to mod
Note
A complete application should include the following:
For New Dischargers, EPA Form 2A or 2D requirements, Engineering Alternatives Analysis, Fee
For Existing Dischargers (POTW), EPA Form 2A, 3 effluent pollutant scans, 4 2nd species WET
tests.
For Existing Dischargers (Non-POTW), EPA C rrect analytical re uirements based
on industry category.
Complete applicable sections below. If not applicat:
1. Basic Facility Information
Facility Information
Applicant/Facility Name:
The Chemours Company / Chemours Fayetteville Works
Applicant Address:
1007 Market Street, Wilmington, DE 19899
Facility Address:
2282 C Highway 87 W, Fayetteville, NC 28306-7332
Permitted Flow:
1.58 MG
Facility Type/Waste:
JOR 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
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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, stormwater, and surface water from a stream
located on the southern portion of its property.
The flow from Outfall 003 consists primarily of contaminated surface water, stormwater, and groundwater,
which must be treated to remove at least 99% of the HFPO-DA (GenX), PFMOAA, and PMPA. This
stream, often referred to as "Old Outfall 002," was used to discharge process wastewater from the facility
prior to June 2012, when the process wastewater discharge was relocated to the current outfall location (for
permit NC0003573) above Lock and Dam #3 (also known as Wi m O Huske Dam) in the Cape Fear
River. Pursuant to the Consent Order, Chemours is required to implement a system to capture and treat the
dry weather flow (baseflow) 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 shak4n addition and at a minimum,
be at least 99% effective in controlling indicator parameters, HFPO-DA, PFMOAA, and PMPA, i.e. 99%
removal of these parameters. The issuance of this pe it will allow Chemours to egin this remediation to
meet the Consent Order requirement and reduce PFS ding to t Cape Fear
Additionally, as part of the Consent Or Chemours was required to conduct a Mass Loading Assessment.
The summary report was submitted to EQ on,December 6, 2019. The report assessed all known sources
of per- and polyfluoroalkyl substances (PFAS) on and around the site and their potential mass loadings to
the Cape Fear River using data from the May, June, and September 2019 sampling for the facility.
Chemours preliminarily estimated that remediating the baseflow (dry weather flow) from this channel will
reduce overall loading of Total Table 3+ PFAS compounds to the river by 26% based on an average of
these two sampling a nts (Cape F River PFAS Loading Reduction Plan - Supplemental Information
Report, November 20
This outfall is named Outfa 03 in this new permit to a ow for the potential consolidation of Chemours'
other NPDES wastewater permit, NC0003573, in the future.
B. Prouosed Treatment
L. 1%, -440
The proposed treatment system includes aldaril4o collect dry weather baseflow in the creek bed/channel
(estimated to be 540 gallons per minute with a maximum flow of 610 gpm) and some seeps and
groundwater, for a total flow capacity at the dam (collection system) of 670 gallons per minute (gpm).
The treatment system is designed to treat a maximum flow of 750 gallons per minute (gpm), which will
provide a treatment safety factor in the event Chemours has trouble getting the flow through the carbon
systems. The Permitted Flow allowance of 1.58 million gallons per day (MGD) is for the addition of
future flows from on -site seeps and other groundwater remediation projects expected at the site.
The system is expected to be able to remove numerous PFAS compounds, including the indicator
parameters HFPO-DA (GenX), PFMOAA, and PMPA. As described above, the Consent Order specifies
that HFPO-DA and PFMOAA are to be removed from the Old Outfall 002 channel by at least 99%. The
Consent Order required Chemours to complete, 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 NPDES permit application.
Page 2 of 19

From time -to -time the Middle Cape Fear River has experienced flooding conditions which are
documented to cause a significant increase in water levels below Lock and Dam 93, consistent with the
location of proposed Outfall 003. During these events a backwater condition propagates upstream in the
"Old Outfall 002 Stream". Historical observation indicates that the Old Outfall 002 Stream levels can rise
significantly (consistent with the flooded Cape Fear River levels) and would be expected, at times, to be
equal to or significantly greater than the invert elevation of the treatment system intake dam and
associated pumping system. During these flooded backwater conditions elevated sediment load and
reduced flow velocity gradients are expected to cause significant sediment deposition within the
collection dam and pumping structure. The sediment load may cause failure of the pumping and
treatment system during the flooded backwater condition. Requirement for treatment shall be suspended
during these force majeure flooding events and be allowed 48 hours after the backwater stream level falls
below the invert of the intake collection dam to safely maintain the influent collection structure and re-
initiate collection and treatment. The triggering Cape Fear River flood elevations; event
documentation and notification requirements; and procedur for treat nt cessation and safe restart shall
be included in the approved Dam Operation and Maintenance Plan.
This proposed treatment system will consist of the following components:
1) Influent Oxidation, Coagulation & pH Austment
This treatment system includes an influent oxidation/coagulation p adju\for pretreatment of
the ultrafiltration (UF) feed (pH adjust ent/oxidation/coagulation). The pH adjustment will be done using
sodium hydroxide. Additional iron odation 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 boosterpumps. Safety Data Sheets (SDSs) are
attached for the chemicals to be utilized at th 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 rec cle tank) and filtered in downstream removal processes (thickener and rotary -
fan filter press).
2) Ultrafiltratio
This design includes 4*etreatment before the Granu Activated Carbon (GAC) stage. The OF will
perfo 1 the role of solids removal upstream of the GAC units. The OF will provide an absolute barrier to
solids at ALI
µm range. P r e man f taring vendor, the OF membrane will provide additional TOC
removal
The OF back pul waste recycle be captured in a weir tank to allow solids to settle and then will be
recycled through the system after b pumped back to the influent oxidation/coagulation /pH adjustment
tank. The settled solids in the weir nk (the back -pulse 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 cleaned with a low concentration of citric acid. The cleaning
solution will be captured in a Clean -In Place (CIP) tank and neutralized in it. Following neutralization, the
CIP water will be recycled through the treatment system after being pumped back by CIP neutralization
pumps to the influent oxidation/coagulation /pH adjustment tank.
3) Granular Activated Carbon (GAC) Adsorption
Based on GAC adsorption studies, PFAS removal to meet discharge requirements (per the CO), is expected
to be accomplished using GAC adsorption. The system design for this application includes a total of six (6)
12' diameter x 5' diameter straight side vessels in a three (3) pass configuration capable of swapping
lead/middle/lag. Each GAC vessel can hold up to 20,000 lbs. of GAC. The GAC beds will be sluiced out
Page 3 of 19

upon exhaustion and the new bed sluiced back into the vessel. The GAC vessels have backwashing
capability. Sizing, quantities and configuration may be modified during process optimization.
Chemours' initial process control sampling plan consists of sampling the influent to the GAC system once
per week, sampling the lead, middle, and lag units twice a month, and additional sampling as needed when
nearing GAC unit replacement criteria. These samples will be analyzed by Chemours inhouse laboratory.
The lead GAC bed will be changed out when PFMOAA in the lead GAC unit equals PFMOAA out of the
lead GAC unit. This will ensure full utilization of the carbon bed. Chemours will test for PFMOAA between
each GAC unit to determine when units need to be rotated or disposed because this compound's affinity to
carbon is a bit less than HFPO-DA. This was tested out during Chemours' pilot scale study and a 99%
reduction was maintained for both compounds in the lag (or third) GAC bed effluent.
4) Solids Handling and Treatment
The treatment system includes a containerized sludge handling sy m with sludge pump, polymer make
down/injection system, in -line mixer and a thickener unit and rotary f n press skid. The rotary fan press
will be mounted on a sump with a pump to return filtrate from the pr to the head of the plant into the
influent oxidation/coagulation /pH adjustment tank. Additionally, the s handling system will include
a screw conveyor to move the sludge out of the container/press and into 1 off for storage, until the
sludge accumulates enough to be hauled off site. Solid waste is to be sh to an approved waste
management facility for disposal per Federal and State RegulationsX
5) Discharge
The treated water will be discharged and reintroduc03. The discharge location will be
downstream of the capture dam, and will flow from the Cape Fear River. On October 16,
2019, the division issued a 401 Certification for the t weir to create a small in
reservoir, DWR Project 92019-1146. The purpose of the project was to create a pool from which to
withdraw water, treat it in an upland facility and discharge below the we he permanent impacts for the
project were 270 Linear Feet of stream (Old Outfall 002). Mos4f the impacts were associated with the
stabilization of the stream bed and bank with rip -rap behind the weir. No mitigation was triggered as the
project did not exceed the s threshold of 300 LF of stream. The Army Corps of Engineers issued a 404
(NWP 38) forth ro* on ber 29, 2019.
C.Fac ackeround
Currently, no process wastewa from Clemours is discharged. The only process wastewater discharged
comes from Chemours' tenants DuPont andwKuraray. That wastewater is covered under the NPDES
discharge permit 4NC0003573. This permit #NC0089915 is for the collection and treatment of the
contaminated dry weather flow (groundwater and surface water) in Chemours Old Outfall 002 channel.
Renewal of Chemours'per t N 003573 will be addressed separately from this permit.
2. Receiving Waterbody Information
Receiving Waterbody Information
Outfalls/Receiving Stream(s):
Outfall 003 — Cape Fear River
Stream Segment:
18-(26.25)
Stream Classification:
C, WS-1v
Page 4 of 19

Drainage Area (mi2):
4852
Summer 7Q10 (cfs):
467 (17.14 — used in limit calculations to account for dilution,
the number is based on the modeling)
Winter 7Q10 (cfs):
603
30Q2 (cfs):
900
Average Flow (cfs):
4220
IWC (% effluent):
12.5% (based on the model)
303(d) listed/parameter:
No, the segment is no on the 2018 303(d) list
Subject to TMDL/parameter:
Yes — State-wid TMDL implementation.
Outfall 002- -16 /
Sub-basin/HUC:
USGS Topo Quad:
Duart
jV 11%L
3. Effluent Data Summary
N/A — New Discharge
This is a new permit for the collection
the Cape Fear River. Previously ft
as "Old Outfall 002".
Q
In
y weather flow in a channel leading to
process wastewater and referred to it
Instream monitoring may be requi certain si afions, for example: 1) to verify model predictions
when model results for instream DO are within 1 mg/l of instream standard at full permitted flow; 2) to
verify model predictions for outfall diffuser; 3) to provide data for future TMDL; 4) based on other
instream 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 an 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
sampling efforts are detailed in the Updated PFAS 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). As part of this permit, instream
monitoring for PFAS compounds will be required.
Page 5 of 19

Is this facility a member of a Monitoring Coalition with waived instream monitoring (YIN): Y
Name of Monitoring Coalition: Middle Cape Fear Basin Association
5. Compliance Summary
Summarize the compliance record with permit effluent limits (past 5 years): This is a new permit.
Summarize the compliance record with aquatic toxicity test limits and any second species test results
(past 5 years): This is a new permit.
Summarize the results from the most recent con
6. Water Quality -Based Effluent Lim
Dilution and MixingZones
ones
In accordance with 15A NCAC 2B.0206, the following eam flows are used for di on considerations
for development of WQBELs: 1Q10 streamflow (acute Aquatic Life); 7Q10 streamflow (chronic Aquatic
Life; non -carcinogen HH); 30Q2 streamflow (aesthetics); annual average flow (carcinogen, HH).
If applicable, describe any other dilution factors considered (e.g. ®'base on CORMIX model results):
Geosyntec Consultants of NC has submitted IX model results o alf of The Chemours
Company FC, LLC for the primary discharge Outfall 002 of their Fayetteville Works site discharging to
the Cape Fear River, classified WS-IV, approximately I,AO feet a�o4 the William O Huske Dam aka
Lock and Dam 3 in Bladen County. The discharge was modeled because of concerns over incomplete
mixing due to resence of the lock and dam system and background concentrations from site runoff,
aerial depositiNconsisten
undwater flow containing per -and polyfluoralkyl substances (PFAS)
into th river.
The CORMIX modtization used The Army Corps of Engineers 2016 bathymetric survey
data which showed er cross -sec on profile from the point of discharge to just above Lock
and Dam 3. Critical river flows were obtaine om 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.
The model showed continued mixing up to 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. The 8:1 dilution is used 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 213. The IWC from using standard procedures under 7Q10 flow conditions of 467 cubic feet per
second (cfs) would be 9% versus 12.5% at an 8:1 dilution. The 8:1 dilution factor, modeled and
established for Chemours' upstream discharge at Outfall 002 was used as a conservative estimate to
assess effluent limits and monitoring requirements for the discharge (Outfall 003) regulated in this permit.
Page 6 of 19

It should be noted that the model produced an effective summer 7Q10 (7QIOs) value of 17.14 cfs. This is
a very conservative assumption, as it is substantially lower than the USGS estimate of 467.0 cfs for the
7Q 1 Os. Because the CORMIX model provides a very high level of protection for the receiving stream and
the downstream water users, the effective 7QIOs was be used in the Reasonable Potential Analysis (RPA)
for Outfall 003.
If applicable, describe any mixing zones established in accordance with I5A NCAC 2B. 0204(b): N/A.
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 quali standard. Secondary TBEL limits
(e.g., BOD= 30 mg/1 for Municipals) may be appropriate if deeme stringent based on dilution and
model results.
If permit limits are more stringent than TBELs, describe how limits were developed.- See "Dilution and
Mixing Zones" Section above.
Ammonia and Total Residual Chlorine Limitation
Limitations for ammonia are based on protection o tic life utilizing\amchroinnic criterion of
1.0 mg/1(summer) and 1.8 mg/1(winter). Acute ammonia limits are deririteria,
utilizing a multiplication factor of 3 for Municipals and a multiplication -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/i (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 pe mit renewal: The facility
conducted a comprehensive4evaluation the dryweathe ow ine deck bed (channel) and submitted
results on the EPA Form 2on. The analysis indicates that there is no ammonia or TRC.
0 4 AV- %IkkL
.
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 1/2 detection limit for "less than" values; and 4) stream flows used for dilution
consideration based on 15A NCAC 213.0206. 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 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: Silver and Cobalt.
Page 7 of 19

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: Cadmium,
Copper, Cyanide, Lead, Thallium, Selenium, Mercury.
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: Aluminum, Arsenic, Barium, Beryllium, Total Phenolic Compounds, Total
Chromium, Fluoride, Molybdenum, Nickel, 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 Limitations Ad*k
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 Al ernative WET Test Procedure in
NPDES permits, using single concentration screening tests, with le dilution follow-up upon a test
failure.
Describe proposed toxicity test requirem his is a Major ustrial facility, and a chronic WET limit
at 12.5% with quarterly frequency is establijkd in the pee_rmit.
Mercury Statewide TMDL Evalua
There is a statewide TMDL for mercury approved by EPA in 2012. The TMDL target was to comply
with EPA's mercury fish tissue criteria (0.3 mg/kg) for human health protection. The TMDL established a
wasteload allocation for point sources of 37 kg/year (81 lb/year), and is applicable to municipals and
industrial facilities with known mercury discharges. Given the small contribution of mercury from point
sources (-2% of total load), the TMDL emphasizes mercury minimization plans (MMPs) for point source
control. Municipal facilities > 2 MGD and discharging quantifiable levels of mercury (>1 ng/1) will
receive an MMP requirement. Industrials are evaluated on a case -by -case basis, depending if mercury is a
pollutant of concern. Effluent limits may also be added if annual average effluent concentrations exceed
the WQBEL value (based on the NC WQS of 12 ng/1) and/or if any individual value exceeds a TBEL
value of 47 ng/1. 4
Describe proposed permit actions based on mercury evaluation: This is a new permit and the Division
has no historic data to conduct a comprehensive evaluation. The RPA does not indicate the need for a
limit and the effluent demonstrated compliance with the annual average Technology Based Effluent Limit
for mercury of 47.0 ng/L. No limit is required but quarterly monitoring is recommended.
Other TMDL/Nutrient Management Strategy Considerations
If applicable, describe any other TNDDLs/Nutrient Management Strategies and their implementation
within this permit: N/A.
Other WQBEL Considerations
If applicable, describe any other parameters of concern evaluated for WQBELs:
Page 8 of 19

The Technology Based Effluent Limits were the guiding criteria used to develop permit limitations for
HFPO-DA, PFMOAA, and PMPA.
When EPA develops PFAS criteria or the State adopts standards for any of the compounds generated by
Chemours, the Division will conduct a reasonable potential analysis and reopen the permit to include the
new limits, if they are more stringent than the TBELs.
If applicable, describe any special actions (HQW or ORW) this receiving stream and classification shall
comply with in order to protect the designated waterbody.
If applicable, describe any compliance schedules proposed for this permit renewal in accordance with
I5A NCAC 2H 0107(c) (2) (B), 40CFR 122.47, and EPA May 2007 Memo.
If applicable, describe any water quality standards variances pr in accordance with NCGS 143-
215.3(e) and I5A NCAC 2B. 0226 for this permit renewal: Nl
7. Technology -Based Effluent Limitations s)
Describe what this facility produces: This is a surf, dwater remedi ermit for the Chemours
facility that produces organic chemicals.
List the federal effluent limitations guideline (ELG) forNthis facili A.
If the ELG is based on production or flow, document how the aver ge production/flow ue was
calculated. N/A.
For ELG limits, document the calculations used to develop TBEL limits: N/A.
If any limits are based o est professional judgement (BP.I), describe development: N/A.
Document any TBELs' that are more stringent than WQBELs: Initially, HFPO-DA and PFMOAA were
chosen as the two PFAS compounds that would be used to indicate reductions of Total PFAS in the
remediated surface water. As additional studies have been performed since the Consent Order, PMPA
has been added as an indicator parameter since the laboratory experiments demonstrated its low affinity
for GAC absorption. Therefore, TBELs for HFPO-DA, PFMOAA, and PMPA were calculated while
recognizing the Consent Order's requirement that the treatment system removes at least 99% of HFPO-
DA and PFMOAA.
The 99% rem also consist ith the ES permitting procedure for establishing BAT for waste
streams that don e promulgat ffluent Guidelines.
The facility provided ngineering Report on Wastewater Treatability. The Report demonstrated that
the proposed Granular Activated Carbon (GAC) system is able to remove 99% of the total Table 3+
PFAS compounds (as listed in NPDES permit application) present in the wastewater based on current
analytical reporting limits and influent concentrations. The GAC system showed that when indicator
compounds PFMOAA, PMPA, and HFPO-DA are removed at the rate of 99%, the Total Table 3+
compounds (as listed in NPDES application) were also removed at the rate of 99% based on current
analytical detection levels.
Data provided in the application showed dry weather baseflow to have influent concentrations for the two
indicator parameters at 6.0 µg/L for HFPA-DA, 85 µg/L for PFMOAA, and 5.4 µg/L for PMPA. This
was based on a single 24-hour composite influent sample. The dry weather flow (baseflow) will be treated
utilizing three GAC units in series versus the typical two GAC unit in series to assure compliance with
permit limitations. The lead GAC bed will be changed out when PFMOAA in the influent to the lead
GAC unit equals PFMOAA effluent of the lead GAC unit. This will ensure full utilization of the carbon
Page 9 of 19

bed. Chemours will test for PFMOAA between each GAC unit to determine when units need to be rotated
or disposed because this compound's affinity to carbon is a bit less than HFPO-DA. This was tested out
during Chemours' pilot scale study and a 99% reduction was maintained for all three compounds in the
lag (or third) GAC bed effluent. In accordance with the Engineering Report, the expected effluent at 99%
removal would be as follows:
HFPO-DA = (6.0 µg/L/100%) * 1% = 0.06 µg/L
PFMOAA = (85.0 µg/L/100%) * 1% = 0.85 µg/L
PMPA = (5.4 µg/L/100%) * 1% = 0.054 µg/L
Therefore, three limits will be placed on the PFAS indicator parameters in the new permit. First, HFPO-
DA, PFMOAA, and PMPA TBELs of 0.06 µg/L, 0.85 µg/L, and g/L respectively. This is based
on Chemours data provided in the application and pilot study.
In addition, and as required by the Consent Order, the treatmeor
ill have to demonstrate 99%
removal for HFPO-DA, PFMOAA, and PMPA based on monthly average concentration data.
% Removal =
Where: Influent = monthly average influent
Effluent = monthly average eAwk
This percent removal will be reported mon y wit Chemours ele nic Discharge Monitoring Report
(eDMR) data. If the influent HFPO-DA or PFMOAA concentrations to the water treatment system are
equal to or less than 200 ng/L and 500 ng/L, respectively, then the water treatment system effluent
concentrations of less than the current reporting ymauine
/L and 5 ng/L, respectively) shall be
considered as achieving 99% removal.The addition of PMPA as an indicator parameter additional carbon treatment units and
Chemours has committed to making the necessary improvements to the treatment system and complying
with the PMPA technology based effluent permit limits by Jan. 31, 2021. All other limits are effective
upon commencement of discharge. Furthermore, since these are technology based effluent limits, if
appropriate, after 3 years of treatment system operation the division will evaluate effluent limits and
adjust the l * if the analysis indicates an roved performance.
Document any T s;4'
ngent than previous permit: N/A. This is anew permit.
8. Antidegradation ew/Expanding Discharge)
The objective of an antidegradation review is to ensure that a new or increased pollutant loading will not
degrade water quality. Permitting actions for new or expanding discharges require an antidegradation
review in accordance with 15A NCAC 213.0201. Each applicant for a new/expanding NPDES permit
must document an effort to consider non -discharge alternatives per 15A NCAC 2H.0105(c)(2). In all
cases, existing instream water uses and the level of water quality necessary to protect the existing use is
maintained and protected.
If applicable, describe the results of the antidegradation review, including the Engineering Alternatives
Analysis (EAA) and any water quality modeling results: The facility provided an EAA to justify the
Page 10 of 19

chosen disposal alternative for this new discharge; the complete EAA document can be found within the
application in DWR's Laserfiche files.
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. Reuse is currently not a feasible option, because, including but
not limited to, - the Consent Order requires Chemours to accelerated reduction of PFAS contamination in
the Cape Fear River and downstream water intakes within a two-year period, and it would be difficult for
Chemours to implement this in an accelerated manner. Chemours m valuate this alternative more
closely in the future.
The Present Value Costs for the next 20 years was calculat lowing alternatives using an EPA
discount factor of 3.5%; the Costs are presented below:
Land Application — $86,000,000
Wastewater Reuse in the Facility - $69,600,000 (i es riparian restoratN
ith this
alternative include the riparian damage and distance the cap dam
Trucking Offsite - $8,710,000,000
Direct Discharge- $67,000,000 ohib,
As compared to other alternatives, and in accordance with 15A NCC 2H .0105(c)(2), the Engineering
Alternatives Analysis provided justification for a direct discharge to surface water alternative and
indicated that the direct discharge is the most environmenta sound alte ative selected from all
reasonably cost-effective options.
9. Antibacksliding eview
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 (YESINO): N/A. This is a new permit.
If YES, confirm that antibacksliding provisions are not violated: N/A.
10. Monitoring Requirements
Monitoring frequencies for NPDES permitting are established in accordance with the following
regulations and guidance: 1) State Regulation for Surface Water Monitoring, 15A NCAC 2B.0500; 2)
NPDES Guidance, Monitoring Frequency for Toxic Substances (7/15/2010 Memo); 3) NPDES Guidance,
Reduced Monitoring Frequencies for Facilities with Superior Compliance (10/22/2012 Memo); 4) Best
Professional Judgement (BPJ). Per US EPA (Interim Guidance, 1996), monitoring requirements are not
considered effluent limitations under Section 402(o) of the Clean Water Act, and therefore anti -
backsliding prohibitions would not be triggered by reductions in monitoring frequencies.
For instream monitoring, refer to Section 4
Page 11 of 19

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
Parameter
Current Permit
Proposed Change
Basis for Condition/Change
Flow
N/A (new permit)
MA 1.58 MGD
NCAC 213.0505
BOD5
N/A (new permit)
NSA 30.0 mg/L
W Based on protection of DO
D ` mg/L
standa 5A NCAC 213.0200
TBEL. Best Professional Judgement.
TSS
N/A (new permit) IN,
%.0mgmg
5.0 mg/L
h,
Temperature
Imik
N/A (new ermit)
The am lent water
WQBEL. State WQ standard, 15A
temperature to exceed
AC 213.0200
32°C 40
DO
N/A (ne ermit)
Wee
WQBEL. State WQ standard, 15A
upstrea ownstream
NCAC 2B .0200
Monitoring Only
HFPO-7 (GenX)
N/A (new permit)
06 µg/L
TBEL, based on the Consent Order
DM 0.06 µg/L
and BPJ/BAT
PFMOAA
N/A (new p
0.85 µg/L
TBEL, based on the Consent Order
,,jDM
0.85 µg/L
and BPJ/BAT
PMPA
MA 0.054 µg/L
TBEL, based on the Consent Order
Nr
DM 0.054 µg/L
Effluent and Intake
and BPJ/BAT
Based on the Consent Order
PFAS compounds
N/A (new rmit)
Monitoring Only
(Table 3+ and/or
(variable frequencies)
EPA Method 357
mod)
pH
N/A (new permit)
6.0 — 9.0 SU
WQBEL. State WQ standard, 15A
NCAC 213.0200
Page 12 of 19

Parameter
Current Permit
Proposed Change
Basis for Condition/Change
Total Phosphorus
N/A (new permit)
Monthly Effluent
State WQ Rule, 15A NCAC 213
Monitoring Only
.0500
Conductivity
N/A (new permit)
Monthly
State WQ Rule, 15A NCAC 213
upstream/downstream
.0500
Monitoring Only
Toxicity Test
N/A (new permit)
Chronic limit, 12.5%
WQBEL. No toxics in toxic
effluent
amounts. 15A NCAC 213.0200 and
15A NCAC 213.0500
Total Hardness
N/A (new permit)
Quarterly Efflu
State WQ standard, 15A NCAC 2B
Monitoring
Quarter ent
.0200
Total Selenium
N/A (new permit)
State WQ standard, 15A NCAC 213
Mon Only
.0200
Total Silver
N/A (new permit)
µg/L
State andard, 15A NCAC 213
.0200
DM 2.0
Total Cobalt
N/A (new permit)
23.9 µg
State WQ standard, 15A NCAC 2B
.0200
DM 23.9 µg/L
Total Cadmium
N/A new ermit)
Quarterly Effl t 14
to WQ standard, 15A NCAC 2B
Monitoring n
200
Total Copper
N/A (new permit
Qua Effluent
State WQ standard, 15A NCAC 213
Monit Only
.0200
Total C 111rA
N/A (new permit)
Quarterly Effluent
State WQ standard, 15A NCAC 213
1%1011
Monitoring Only
.0200
Total Lead
N/A (new pe
uarterly Effluent
State WQ standard, 15A NCAC 213
Monitoring Only
.0200
Total Thallium
N/A (new permit
Quarterly Effluent
State WQ standard, 15A NCAC 213
Monitoring Only
.0200
Mercury
N/A (new permit)
Quarterly Effluent
2012 State TMDL and NPDES
Monitoring Only
Implementation Guidance.
Electronic
N/A (new permit)
Required
In accordance with EPA Electronic
Reporting
Reporting Rule 2015.
MGD — Million gallons per day, MA — Monthly Average, DM — Daily Max
13. Public Notice Schedule
Permit to Public Notice: xx/xx/2020
Page 13 of 19

Per 15A NCAC 21-1.0109 & .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)
RPA Sheets
o Input Sheet
o Data Sheets
o RPA Sheet
o Dissolved to Total Metal Calculator heet
NPDES Implementation of Instream Dissolved Metals Standards — Freshwater Standards
Safety Data Sheets (SDSs) for the chemicals to be utilized at the wastewater treatment system
Page 14 of 19

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/l
(Dissolved)
Chronic FW, µg/l
(Dissolved)
Acute SW, µg/l
(Dissolved)
Chronic SW, µg/l
(Dissolved)
Arsenic
340
150
69
36
Beryllium
65
6.5
---
---
Cadmium
Calculation
Calculation
40
8.8
Chromium III
Calculation
Calculation
---
---
Chromium VI
16
11
1 LVAM50
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 11W
81
Table 1 Notes: 1%
1. FW= Freshwater, SW= Sal rater
2. Calculation = Hardness dependent standard
Only the aquatic life standards listed above are express dissolved form. Aquatic life
standards for Merry and selenium are still expressed as TotRecoverable Metals due to
bioaccumulative concerns (as are all human health standards for all metals). It is still
necessary to evaluate total rec verable aquatic life and human health standards listed in 15A
NCAC 213.0200 (e.g., arsenic a 10 µg/l for human health protection; cyanide at 5 µg/L and
fluoride at 1.8 mg/L for aquatic life protection).
Table 2. Dissolved Freshwater Standards for Hardness -Dependent Metals
VThe Water Effects Ratio (WER) is equal to one unless determined otherwise under
15A NCAC 02B .0211 Sutagraph (11) (d)
Metal
NC Dissolved Standard, µg/l
Cadmium, Acute
WER*{1.136672-[ln hardness](0.041838)} e^{0.9151 [In hardness]-
3.1485}
Cadmium, Acute Trout
waters
WER*{1.136672-[ln hardness](0.041838)} e^{0.9151[ln hardness] -
3.62361
Cadmium, Chronic
WER*{1.101672-[ln hardness](0.041838)} e^{0.7998[ln hardness]-
4.4451 }
Chromium III, Acute
WER*0.316 e^{0.8190[ln hardness]+3.7256}
Chromium III, Chronic
WER*0.860 e^{0.8190[ln hardness]+0.6848}
Copper, Acute
WER*0.960 e^{0.9422[ln hardness]-1.7001
Page 15 of 19

Copper, Chronic
WER*0.960 • e^{0.8545[ln hardness]-1.7021
Lead, Acute
WER* { 1.46203- [ln hardness] (0.145712)1 e^ { 1.273 [ln hardness] -
1.4601
Lead, Chronic
WER* { 1.46203- [ln hardness] (0.145712)1 e^ { 1.273 [ln hardness] -
4.7051
Nickel, Acute
WER*0.998 e^{0.8460[ln hardness]+2.2551
Nickel, Chronic
WER*0.997 e^{0.8460[ln hardness]+0.05841
Silver, Acute
WER*0.85 • e^{1.72[ln hardness]-6.591
Silver, Chronic
Not applicable
Zinc, Acute
WER*0.978 e^{0.8473[ln hardness]+0.8841
Zinc, Chronic
WER*0.986 e^{0.8473[ln hardness]+0.8841
The RPA process itself did not chan�was the result of the new metals standards. Hwever,
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.
N
The hardness -based standards require some knowledge of the efflu It
and instream (upstream)
hardness and so must be calculated case -by -case for each discharge.
Metals limits must b 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 p6s i 1 n i r case-s *fic translators developed in accordance with
established methodologv.
14
The RPA is designed to predict the maximum 4ely 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 potenfial 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...s
• Effluent hardness and upstream hardness, site -specific data is preferred
• Permitted flow
Page 16 of 19

• Receiving stream classification
In order to establish the numeric standard for each hardness -dependent metal of concern
and for each individual discharge, the Permit Writer must first determine what effluent and
instream (upstream) hardness values to use in the equations.
The permit writer reviews DMR's, Effluent Pollutant Scans, and Toxicity Test results for any
hardness data and contacts the Permittee to see if any additional data is available for
instream hardness values, upstream of the discharge.
If no hardness data is available, the permit writer may choose to do an initial evaluation
using a default hardness of 25 mg/L (CaCO3 or (Ca + Mg)). Minimum and maximum limits
on the hardness value used for water quality calculations are 25 mg/L and 400 mg/L,
respectively.
If the use of a default hardness value results m ahardness-dependent metal showing
reasonable potential, the permit writer contacts the Permittee and requests 5 site -specific
effluent and upstream hardness samples ov, a period of one week. The RPA is rerun using
the new data. low 11111k
The overall hardness value used in the water quality calculations is calculated as follows:
Combined Hardness (chronic) Akq� X
_ (Permitted Flow, cfs *Avg. Effluent Hardness, mg/L) + (s7Q10, cfs *Avg. Upstream Hardness, mg/L)
jkj 1jPFN% (Permitted Flow, cfs + s7Q10, cfs)
The Combined ness for acute is the same but the calculation uses the 1Q10 flow.
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:
Cai55 - 1
Ctotal 1 + { [Kpo] [ss(1+a)] [10-6] t
Where:
ss = in -stream suspended solids concentration [mg/1], minimum of 10 mg/L used,
Page 17 of 19

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 convey 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 i4ing the\wingeq/ua)tion.
Ca = s7 10 + w Cw s — s7 10
Qw
Where: Ca = allowable effluent concentration (µg/L or mg/L)
Cwqs = NC Water Quality Standard or federal crite a
Cb = background concentration: ass e zero for\fro
except NH3* (µg/L or mg/L)
Qw = permitted effluent flo s, ma 10)
s7Q10 = summer low flow used to protect aquatichronic toxicity and human health
through the consumpticke of water, fish, and shellfish from noncarcinogens (cfs)
* Discussi re on- g with EPA ow best to address background concentrations
s other than s7Q10 may be incorporat pplicable:
1 Q1 0 = used in the equatio o protect aquatic life from acute toxicity
CA used in 3!quation to otect human health through the consumption of water, fish,
and sh llfish from carcinogens
30Q2 din the equation to protect aesthetic quality
6. The permit writer from
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 18 of 19

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. 4&
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+M ]
25.0
Default vale
Average Upstream Hardness
(mg/L) NV
[Total as, CaCO3 or Ca+M ]
425.0
41L Default value
7Q10 summer (cfs)
17.14
CORMIX model, 8:1dilution
1Q10 cfs ;
14.16
RPA calculation
Permitted Flow (MGD)
1.58
Design flow of treatments stem
Page 19 of 19