2021.02.25_CCO_ChemoursResponseToOldOutfallNOV

The Chemours Company
Fayetteville Works
22828 NC Highway 87 W
Fayetteville, NC 28306

February 25, 2021
Sheila Holman
Assistant Secretary for the Environment
1601 Mail Service Center
Raleigh, NC 27699-1601
[e-mail]

Danny Smith
Director, Division of Water Resources
1601 Mail Service Center
Raleigh, NC 27699-1601
[e-mail]

Re: Notice of Violation & Intent to Assess Civil Penalty and Stipulated Penalty
Tracking Number: NOV-2021-PC-0047
Chemours Company-Fayetteville Works
Bladen County
Dear Ms. Holman and Mr. Smith,
This letter is submitted on behalf of Chemours in response to the above-referenced
Notice of Violation (“NOV”) from DEQ dated January 26, 2021 regarding the recently installed
treatment system for the Old Outfall (now called Outfall 003) at Fayetteville Works. As set forth
below and in the attached materials, this response provides factual details, clarifications and
corrections regarding the events described in the NOV, furnishes the items of additional
information requested by DEQ, including with respect to corrective actions and improvements
undertaken, and responds to the alleged violations of the Consent Order and NPDES Permit
NC0089915 (“the NPDES Permit”). Chemours continues to take actions to improve the
operation of the Outfall 003 treatment system and address challenges posed by substantial rain
events, and subsequent sediment loading into the system, and Chemours will continue to keep
DEQ informed regarding system operations and improvements.

Background

Pursuant to Consent Order paragraph 12(e) and NPDES Permit NC0089915, Chemours
started operation of the treatment system at the Old Outfall on September 30, 2020. The system
reduces PFAS loadings to the Cape Fear River attributable to historic operations at Fayetteville
Works and is one of many remediation actions that Chemours is implementing.

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The Old Outfall treatment system was designed and constructed, using site-specific water
parameters and remediation technologies, pursuant to the requirements of the Consent Order.
The system operates in a challenging and dynamic natural environment, where there is steep,
shifting, and uneven terrain, significant rainfall and other weather events, and the potential for
flooding from both the Old Outfall channel and the Cape Fear River. In other words, the system
is not an “off-the-shelf” piece of equipment operating in static conditions. Further,
notwithstanding the significant personnel and other resource availability challenges created by
the COVID-19 pandemic during much of 2020, the design and construction of the system was
completed, and it became operational, by the original date set forth in the Consent Order,
September 30, 2020. DEQ issued the final NPDES Permit for the system on September 18,
2020, with an effective date of September 30, 2020, the same date as the Consent Order deadline.
Due to this timing, a pre-compliance system commissioning period was not possible, where
system adjustments and improvements are made to optimize performance in real-world
conditions and to respond to challenges that may not have been readily apparent during the
design process.

As set forth further below, the events described in the NOV occurred during the early
months of operation of the system following startup, and these events were associated with
frequent and uncommon substantial rain events (including a 50-year storm event) that resulted in
significant slope failures upstream of the construction area and other operational challenges for
the new system. Chemours timely informed DEQ of these events and challenges, and Chemours
has undertaken, and continues to undertake, corrective actions and improvements to reduce the
likelihood of recurrences and ensure consistent and reliable overall system operations.

Responses to Requests for Additional Information

In the NOV, DEQ requested that Chemours provide additional information with respect
to five numbered items. Those items are noted below, followed by Chemours’s responses.
Further information is provided in attachments, where indicated.
1. Descriptions and timeline of treatment system design improvements.
The treatment system has undergone several operational and design improvements since
startup. These improvements include chemistry adjustments, additional monitoring, the addition
of filtration capacity, and wastewater recovery system design improvements.

Treatment System Chemistry Adjustments

The treatment system chemistry has been and continues to be refined at four main points:
1) pre-filtration, 2) wastewater recovery, 3) sludge dewatering, and 4) filtration cleaning events.

1) Pre-filtration chemistry adjusts the pH and aids filtration in the formation of
flocculant. Operational runtime of the system with varying degrees of changes in the feedwater
conditions have aided in refining the chemistry for pH adjustment, oxidation, and flocculant to

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create a filterable particle. The refinement of pre-filtration chemistry aids in greater uptime and
less wastewater production across system filters.

2) Wastewater recovery chemistry includes a coagulant for rapidly settling solids within
the filters wastewater to produce a recoverable supernatant. The coagulant optimization has
produced less carryover of solids in the supernatant. The return of supernatant to the headworks
with lower solids content produces less solids loads for the filters, greater uptime, and less
wastewater production.

3) Sludge dewatering chemistry is utilized to thicken the sludge prior to dewatering
steps. A combination coagulant and polymer are added to transform the sludge to a solid
through the dewatering steps. This dewatering chemistry has allowed the system to remove
dewatered solids from the water cycle. The removal of solids within the system facilitates
sustainable filtration operations.

4) Filtration cleaning chemistry is utilized for removing solids directly on the surface of
the filter and increasing the flow through the filter. The chelating agents enter into the
wastewater stream and inhibit wastewater recovery and sludge dewatering. The elimination of
chelating agents in the wastewater stream starting in mid-January 2021 allows the wastewater
chemistry and sludge dewatering chemistry to separate the water and solids effectively. This
returns supernatant with lower solids content to the headworks of the filters and, as of mid-
February 2021, increases the production of solids removed from the water cycle.

Additional Monitoring

The increase in system monitoring has focused on 1) raw water conditions, 2) flow
production goals, and 3) carbon exchange events.

1) Raw water conditions are closely monitored for pH and turbidity. An inline turbidity
analyzer has been added to the already installed pre-filtration and post-filtration turbidity
analyzers. The raw water turbidity analyzer provides operation staff a key data point to alert to
changes in feedwater conditions. The system responds to the changes in raw water through
chemistry and filtration cleaning events to optimize recovery and uptime.

2) Flow production goals are incorporated in the Programmable Logic Controller
(“PLC”) and operator interface to identify flow conditions at the system relative to goals. The
operator interface readout provides the average flow for the day and remaining production
requirement for meeting dry weather flow in a daily period. The improved access to flow
production totals and key performance indicators provides the operation staff with information
for balancing maintenance downtime with production requirements.

3) The carbon vessels are designed and built to industry standards to facilitate exchange
of exhausted carbon with new carbon. Instructions have been integrated into procedures and
highlighted to address trace PFAS residuals during carbon exchanges, including:

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· Removal of all residual biofilm and carbon fines from the internal carbon vessel and
underdrain;
· Utilization of treated water for carbon sluice, backwash and forward rinse; and
· Sampling of vessels and analysis for PFAS compounds prior to placing in service.

Addition of Filtration Capacity

Additional filtration capacity was added to the system to increase filtration production
volumes. An emergency filtration trailer with pressurized media filtration was brought onsite
and has now been replaced with an ultrafiltration container. The additional filtration equipment
delivers three filter trains, with the ability to take one filter train offline and meet system demand
with the remaining two trains when solids are being removed efficiently.

Wastewater Recovery System Design Improvements

Wastewater recovery system design improvements have included adding a mechanical
filtration skid on the wastewater recovery line and a conical bottom clarifier with the water
recovery system. While incorporating the conical bottom tank design improvements, a
temporary system of transferring sludge to frac tanks for settling and decanting has been
employed.

Mechanical filtration is installed on the wastewater recovery line to capture solids
carryover in the supernatant. Filtration of the supernatant reduces the solids returned to the
headworks, lessens solids loads for the filters, improves uptime, and reduces wastewater
production across the system.

A conical bottom clarifier was installed to concentrate the wastewater sludge and
increase the consistency of the sludge for dewatering events. The enhanced sludge consistency
in the cone tank is transferred to the dewatering equipment, which is now being used for solids
dewatering production. The system’s ability to remove dewatered solids from the water cycle
facilitates sustainable filtration plant operations.

While implementing the wastewater recovery system design improvements, a temporary
system of transferring sludge to frac tanks has been employed to retain water production.
Wastewater from the filters is sent to the backpulse tank for the separation of sludge and water.
The supernatant water from the backpulse tank is returned to the headworks of the system. The
sludge is transferred to frac tanks for further separation and solids settling. The frac supernatant
water is returned to the headworks and the sludge is settled and stored for eventual dewatering.

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Timeline of Improvements

· October 19 to 23
o Mechanical filtration of supernatant added within the wastewater recovery system
for reduced filtration solids load.
o Temporary system of transferring sludge to frac tanks is employed.
· October 23 to 27
o Emergency filter trailer is deployed to site, as well as diesel feed pump and
connections.
· November 26
o Carbon exchanges and monitoring includes treated water rinse-in and verification
samples.
· December 6 to 12
o Emergency filter trailer is employed.
· December 8
o Wastewater recovery coagulant refinement enhances the solids settling in the
wastewater.
· December 13
o Ultrafiltration train addition increases filtration capacity.
· December 14
o Conical bottom clarifier installed within wastewater recovery system to aid in
sludge formation for dewatering steps.
· January 15
o Filtration cleaning chemistry eliminates chelating agents and reduces
interferences that prevented water and solids separation in sludge and dewatering
steps.
· January 20
o Inline turbidity monitor added to the raw water.
· February 18
o The sludge dewatering system was brought online in batch mode and has begun
to produce batches of dewatered solids.

2. Average daily flow rates and data.
Data regarding influent and effluent flow rates associated with the system are provided in
the spreadsheet labeled as Attachment A.

Dates on which the average daily flow rate through the treatment system were below 610
gpm and water was overflowing the dam (weir) are shown and explained below and in
Attachment A. Chemours previously notified DEQ of treatment system flow issues for these
dates.

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October 2020 - Date Influent daily average flow (gpm)
11 603
12 573
14 448
15 383
16 339
17 383
18 280
19 288
20 359
21 393

The flow rates shown above between October 11 and 21 followed 1.4 inches of rain on
October 11 and significant sediment loading into the system. Several design improvements were
made during and following this period, as set forth in response to request #1 above.

November 2020 - Date Influent daily average flow (gpm)
13* 601
14* 113
15* 17
16* 0
17* 0
18* 138
24 595
26 559
27 598
28 578
29 588

The flow rates shown above between November 13 and 18 (marked with an asterisk)
followed over 7 inches of rain on November 11 and 12, during a 50-year force majeure storm
event in the region.1 As a result of this storm event and upstream flooding of the Cape Fear
River, the system was temporarily shut down in accordance with the NPDES Permit and system
Operation & Maintenance Plan between November 13 and 18.

1 Chemours’s rain gauge measured over 7 inches of rain on November 11 and 12. The nearby rain gauge at the
Huske Dam indicated over 8 inches of rain on November 11 and 12.

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The flow rates shown above between November 24 and 29 (which were only slightly
below the 610 flow target) were attributable to operational issues over the week of the
Thanksgiving holiday. Manual calculations were made to achieve target flow rates, and an error
in the calculations caused missed targets. Following this period, as a corrective action, a PLC
based calculator was integrated within the automation and displayed at the main PLC/HMI
interface for the system (shown in the photo below), such that data are now readily displayed and
available for operator review and manual calculations are not needed.

December 2020 - Date Influent daily average flow (gpm)
1 604

Although the average daily flow on December 1 was slightly less than 610 gpm, base
flow was treated and flow rates exceeded 610 gpm while water was flowing over the dam on that
date. The influent flow rate was 750 gpm at 9 am on December 1. By that afternoon, drainage
reduced in the creek, and water was below the dam. At that time, pumping rates declined due to
lower base flow, resulting in a daily average under 610 gpm.

3. Operator’s logs.

Operator’s logs for the treatment system for the period from September 30, 2020 through
February 5, 2021 are provided at Attachment B.

4. Solids removal and sediment loading plan.

Several design improvements have been made to facilitate solids removal from the
Outfall 003 treatment system, as described in response to request #1 above. Chemours also
implemented a short-term dredge operation to control sediment loading at the outfall intake
structures and contain sediment during larger storm events. In the next few weeks, additional
filtration units are planned to be added to the treatment system for additional management of

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turbidity and sediments. Chemours is also continuing to evaluate other additional improvements
to the treatment system to address sediment loading and solids removal.

On January 20, 2021, Chemours submitted to DEQ the Fayetteville Outfall 003
Treatment Plant Waste Management Plan, describing storage and disposal procedures for waste
materials, including removed solids, from the treatment system. The Waste Management Plan is
reattached here as Attachment C.

5. Site grading log, sediment and erosion control practices, slopes stabilization
plan, and self-inspection reports.

Self-inspection reports and DEQ inspection reports under Chemours’s Construction
Stormwater NPDES Permit NCG010000 are provided at Attachments D and E, respectively.
Chemours is following the sediment and erosion control and stabilization requirements set forth
in Permit NCG010000. The area around the treatment system remains in construction under
Permit NCG010000. Chemours anticipates achieving final stabilization by this summer,
dependent upon vegetation growth, and will work with DEQ to close out Permit NCG010000 at
that time.

The slope collapse referenced in the NOV was not due to the structural integrity of the
slope, but rather was caused by a channelized concentrated flow of water from the 50-year force
majeure storm event on November 11 and 12 (which exceeded the 10-year design storm
specified in the regulations for sediment and erosion control). The sediment from this slope
collapse was contained at the toe of the slope and did not mobilize into the intake structure for
the Outfall 003 treatment system. After the storm event and inspection occurred, the area was
graded and riprapped to convey water to the outfall channel.

The slope located downstream of the lift station does not impact the Outfall 003 treatment
system intakes and has no effect on system operations. Matting and seeding of the downstream
slopes had not occurred at the time of the storm event on November 11 and 12, as this area was
in active construction and utilizing best management practices in accordance with Permit
NCG010000.

At the time of the DEQ inspection on November 17, the slopes were overly saturated and
could not accommodate construction equipment. Construction work on the downstream slope
and the gulley washout on the upstream slope began on November 18. Following
recommendations from the DEQ inspection on December 1, a rock rundown ditch was installed
and sediment was removed from the channel on December 9. Photos of the construction area
from November and December are provided at Attachment F.

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Responses to Alleged Violations

Chemours respectfully submits the following responses to the alleged violations of the
Consent Order and NPDES Permit2 listed in the NOV.

Consent Order paragraph 12(e).

Chemours installed and commenced operation of the Old Outfall treatment system by
September 30, 2020, as required under the Consent Order. Further, with limited exceptions as
described in this response, associated with frequent and uncommon substantial rain events and
other operational challenges for the new system, the system has captured dry weather flow and
treated it to more than 99% removal efficiency for the indicator PFAS parameters. That
Chemours has implemented design improvements to address weather and operational challenges
for the new system does not mean that the system was “not properly designed” or that there was
a “design failure,” as the NOV alleges. Further, the limited period of system shut down between
November 13 and 18 was in accordance with the NPDES Permit and associated with a 50-year
force majeure storm event that caused substantial flooding of the Cape Fear River.

Permit Effluent Limit.

As noted in the NOV, there was one discrete exceedance of the 0.85 µg/L PFMOAA
effluent limit — on October 29, 2020, the effluent concentration was 1.2 µg/L. This was
attributable to a carbon changeout performed for the treatment system, in which the spent carbon
was removed but a small amount of residual spent material was left in the treatment vessel from
which trace levels of captured PFMOAA then desorbed out.

Promptly upon receiving sampling results showing this exceedance, Chemours reported it
to DEQ and initiated corrective actions to prevent recurrence. Specifically, procedural changes
were made for carbon changeout so that vessels are now opened and inspected to fully remove
all carbon and then rinsed, and then inspections are performed below the cone bottom and at the
media capture screen downstream of each carbon vessel. In addition, procedures were modified
to use treated water for sluicing and forward flushing. Sluicing procedures were also modified to
include bed exchange and rinsing within the system for sample collection. Pursuant to these
procedures, the fresh bed is then left offline until sample results come back verifying that permit
limits will be met.

Permit Flow Requirement.

Chemours respectfully refers DEQ to the response to request #2 above.

2 Chemours understands the NOV to assert that the alleged permit violations also constitute per se violations of 15A
NCAC 2B .0216(4)(d) and NCGS § 143-215.1(a)(6), and not that there is any other or independent basis for alleged
violations of these provisions. Accordingly, Chemours has not specifically addressed these provisions in this
response.

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Permit Operation and Maintenance Requirement.

The NOV alleges that certain events constituted improper operation and maintenance of
the treatment system. These events are listed below as described in the NOV, followed by
Chemours’s responses.

· Flow rates below 610 gpm between October 14 and 21 and November 24 and 29:
Chemours respectfully refers DEQ to the response to request #2 above.
· Treatment system shut down on November 11 and 12: On these dates, the system
remained in operation except for a limited period for essential maintenance, and the
system influent daily average flow rates exceeded 610 gpm. Further, as noted above,
there was a 50-year force majeure storm event on November 11 and 12.
· PFMOAA effluent limit exceedance on October 29: Chemours respectfully refers
DEQ to the response in the “Permit Effluent Limit” section above.
· Sediment loadings into system: Chemours has made several design and operational
improvements to the treatment system to address challenges posed by sediment
loading, as set forth in response to requests #1 and #4 above. Further, as set forth in
response to request #5 above, Chemours has taken several measures to prevent
erosion around the treatment system in accordance with Construction Stormwater
NPDES Permit NCG010000. The sediment loading that has impacted the system was
not caused by erosion around the treatment system, but rather by erosion which
occurred approximately 400-2500 feet upstream of the system intake along 30-foot
vertical channel slopes, as shown below, and which was caused by frequent and
uncommon substantial rain events, including a 50-year force majeure storm event.

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Permit Mitigation Requirement.

As set forth in this response and as previously communicated to and discussed with DEQ,
Chemours has taken, and continues to take, actions to improve the operation of the treatment
system and address challenges posed by substantial rain events and sediment loading into the
system. Accordingly, Chemours respectfully submits that there has been no “failure to mitigate,”
as alleged in the NOV.

***

Chemours respectfully submits that the circumstances here qualify in substantial part as
force majeure events within the scope of Paragraph 32 of the Consent Order, as a combination of
acts of God and extraordinary events beyond Chemours’s control. Chemours and its contractors
allocated the necessary resources, effort, and expertise to meeting the commitments Chemours
had made, and were able to begin operations on time despite having to undertake the last six
months of construction during a global pandemic, which, combined with the late timing of the
permit issuance, left no time for a pre-compliance system commissioning period. Then the
operators were confronted with extraordinary amounts of rain as they were beginning operation
and seeking to optimize performance. Chemours used its best efforts to have the system run as
well as possible as soon as possible, and given the design and timing challenges associated with
this project, and the conditions under which it had to be constructed and commence operation,
Chemours asks that DEQ not seek penalties at this time.

If you have any questions about the information provided herein or would like to discuss
this matter further, please contact me at [e-mail].

Sincerely,

Dawn M. Hughes
Plant Manager
Chemours – Fayetteville Works

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Attachments
A. Spreadsheet of Influent and Effluent Flow Rates
B. Operator’s Logs
C. Fayetteville Outfall 003 Treatment Plant Waste Management Plan
D. Construction Stormwater NPDES Permit NCG010000 Self-Inspection Reports
E. Construction Stormwater NPDES Permit NCG010000 DEQ Inspection Reports
F. Photos of Construction Area

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Cc:
William F. Lane, DEQ
Francisco Benzoni, NC DOJ
Asher Spiller, NC DOJ
Michael Abraczinskas, DAQ
Michael Scott, DWM
Julie Grzyb, DWR

Kemp Burdette, CFRW
Geoff Gisler, SELC

David C. Shelton, Chemours
Todd Coomes, Chemours
Brian Long, Chemours
Kevin Garon, Chemours
Christel Compton, Chemours
Joel Gross, Arnold & Porter
Brian Israel, Arnold & Porter
Thomas Santoro, Arnold & Porter
John F. Savarese, WLRK
R. Steven DeGeorge, Robinson Bradshaw