NC0089915_Chemours Correspondence_20200817

9 Chemours-
August 17, 2020
Sheila Holman
Assistant Secretary for the Environment
1601 Mail Service Center
Raleigh, NC 27699-1601
[e-mail]
Wastewater Permitting
Attn: Chemours Permit
1617 Mail Service Center
Raleigh, NC 27699-1617
[e-mail]
The Chemours Company
Fayetteville Works
22828 NC Highway 87 W
Fayetteville, NC 28306
Re: Chemours - Comments on Draft NPDES Permit No. NC0089915
Dear Ms. Holman,
On July 10, 2020, DEQ issued for public comment Draft NPDES Permit No. NC0089915
(the "Draft Permit") for the water treatment system being implemented by Chemours at the Old
Outfall at the Fayetteville Works site (the "Site"). Chemours is implementing this treatment
system pursuant to paragraph 12(e) of the Consent Order with DEQ and Cape Fear River Watch
that was entered by the Superior Court for Bladen County on February 25, 2019. The treatment
system will reduce PFAS loadings from the Site to the Cape Fear River, and Chemours
anticipates commencing operation of the treatment system by September 30, 2020, subject to
DEQ's issuance of the final NPDES Permit.
DEQ is accepting public comments on the Draft Permit for the treatment system through
August 17, 2020. Chemours respectfully submits the following comments to DEQ.
1. The effluent limits and 99% removal efficiency requirement for PMPA are arbitrary and
not provided for in the Consent Order.
Consent Order paragraph 12(e) states: "The [Old Outfall] treatment system shall meet
such discharge standards as shall be set by DEQ, and shall, in addition and at a minimum, be at
least 99% effective in controlling [PFAS] indicator parameters, GenX and PFMOAA." Pursuant
to this provision, the Draft Permit contains 99% removal efficiency requirements for HFPO-DA
(for GenX) and PFMOAA. The 99% removal efficiency requirements for these two compounds
are in accordance with the requirements of Consent Order paragraph 12(e).
However, the Draft Permit also contains a 99% removal efficiency requirement and
specific effluent limits for a third PFAS compound, PMPA. PMPA is not specified in paragraph

12(e) of the Consent Order, and there are also no applicable regulatory limits or standards for
PMPA.
Notwithstanding the express language of the Consent Order, DEQ's Fact Sheet for the
Draft Permit incorrectly states that the Consent Order requires 99% effective control of PMPA.
See, e.g., Fact Sheet at pg. 2 ("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 shall, in 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 permit will allow Chemours to begin this remediation to meet
the Consent Order requirement and reduce PFAS loading to the Cape Fear River.") and pg. 10
("In addition, and as required by the Consent Order, the treatment system will have to
demonstrate 99% removal for HFPO-DA, PFMOAA, and PMPA based on monthly average
concentration data."). These statements in DEQ's Fact Sheet are incorrect; there is no such
Consent Order requirement for PMPA.
Elsewhere in the Fact Sheet, DEQ does acknowledge that there is no applicable Consent
Order requirement for PMPA and that the newly introduced PMPA removal efficiency
requirement and effluent limits may necessitate Chemours to make design and construction
changes to the treatment system and need additional time for compliance. DEQ selected January
31, 2021 as the effective date for the PMPA removal efficiency requirement and effluent limits
in the Draft Permit (without explaining why this particular date was selected) and stated in the
Fact Sheet that Chemours has committed to make any necessary changes and comply by then.
Chemours is uncertain whether changes will be needed, and whether such changes can be
completed by that or any other date.
While there is no basis for including the PMPA removal efficiency requirement and
effluent limits in the Permit, Chemours does support the Permit requiring monitoring and
reporting for PMPA.1 The analytical work already done by Chemours, which Chemours has
shared with DEQ, has shown that the treatment system being constructed will be effective in
removing PMPA, possibly even to a 99% level, but Chemours will not know the precise
effectiveness until the system is operational. Based on the results of PMPA monitoring, and
taking into account other design and implementation considerations, Chemours may make design
adjustments to the treatment system to further enhance the removal of PMPA. However,
Chemours should not be bound to an arbitrary PMPA removal efficiency requirement and
effluent limits, and especially not when the treatment system was neither specifically designed
nor required by the Consent Order to meet those PMPA limits, and there is no regulatory
provision for such limits.
1 If the PMPA 99% removal efficiency requirement were to be included in the final Permit, the following statement
from Permit section A.(6.) would need to be revised to add PMPA: "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 limits (2 ng/L and 5 ng/L,
respectively) shall be considered as achieving 99% removal." PMPA has a current reporting limit of 20 ng/L, so if
PMPA influent concentrations are equal to or less than 2,000 ng/L, PMPA effluent concentrations of less than the
current reporting limit should be considered as achieving 99% removal.
2

2. The daily maximum effluent limits for PFAS indicator parameters should not be set equal
to the monthly average effluent limits.
In the Draft Permit, DEQ set the daily maximum effluent limits for GenX, PFMOAA,
and PMPA exactly equal to the monthly average effluent limits for these compounds. As shown
in the Fact Sheet, DEQ calculated both the daily maximum and monthly average effluent limit
for each compound by multiplying the concentration of a single 24-hour composite influent
sample for each compound by 1% (i.e., 99% removal). However, DEQ does not explain why it
used this same calculation methodology for both the daily maximum and monthly average
effluent limits.
Setting the daily maximum limit the same as the monthly average limit is inconsistent
with the procedures set forth in EPA's NPDES Permit Writers' Manual.2 In Section 5.2 of the
Manual (Technology -Based Effluent Limitations for Industrial Dischargers), EPA recommends
that daily maximum limits "be calculated by multiplying the long-term average achievable by
implementation of the model technology or process change by a daily variability factor
determined from the statistical properties of a lognormal distribution." EPA recommends using a
default coefficient of variation (CV) value of 0.6 to calculate daily maximum limits if data
regarding variability is not available.
DEQ should recalculate the daily maximum effluent limits for GenX and PFMOAA in
accordance with EPA's guidance (and should do so too for PMPA were PMPA effluent limits to
be included in the final Permit).
3. The effluent limits for PFAS indicator parameters should not be adjusted to become more
stringent after three years.
Draft Permit section A.(3.) states: "if appropriate, after 3 years of treatment system
operation the division will evaluate effluent limits and adjust the limits if the analysis indicates
an improved performance." DEQ's Fact Sheet, at page 10, further states: "since these are
technology based effluent limits [for GenX, PFMOAA, and PMPA], if appropriate, after 3 years
of treatment system operation the division will evaluate effluent limits and adjust the limits if the
analysis indicates an improved performance." These statements are inconsistent with NPDES
permitting regulations and should be removed from the Permit and Fact Sheet.
Specifically, North Carolina has adopted the federal NPDES regulations at 40 CFR
122.29 (a), (b), and (d). See 15A NCAC 02B .0408. Pursuant to 40 CFR 122.29(d), new
dischargers and new sources "may not be subject to any more stringent new source performance
standards or to any more stringent technology -based standards" for a period of "ten years from
the date that construction is completed" or "ten years from the date the source begins to
discharge process or other nonconstruction related wastewater." Accordingly, the technology -
based effluent limits for PFAS indicator parameters established in the Permit for the new
treatment system here should not be adjusted to become more stringent after just three years.
2 Available at https://www.epa.gov/sites/production/files/2015-09/documents/pwm_2010.pdf.

4. The PFAS monitoring requirements in Permit section A.(5.) should be revised.
Section A.(5.) of the Draft Permit contains requirements for monthly and quarterly PFAS
monitoring for upstream and downstream locations in the Cape Fear River as well as for influent
and effluent from the Old Outfall treatment system. DEQ does not provide an explanation in the
Permit or Fact Sheet for these monitoring requirements. Chemours believes that certain
modifications to these requirements are appropriate, as set forth below.
First, the frequency of treatment system influent and effluent monitoring in section A.(5.)
is excessive and should be reduced from monthly and quarterly to semiannually. The treatment
system influent and effluent monitoring requirements in section A.(5.) are in addition to the
Permit's influent and effluent monitoring requirements, effluent limits, and 99% removal
efficiency requirements for PFAS indicator parameters. These multiple requirements for PFAS
indicator parameters are sufficient to monitor and demonstrate the effectiveness of the treatment
system.
Second, the River upstream and downstream monitoring requirements in section A.(5.)
are redundant to the River sampling conducted by Chemours pursuant to the Consent Order,
including sampling to be conducted under the Consent Order Addendum. Chemours believes
that the Consent Order River sampling will provide a comprehensive set of monitoring data and
that additional River sampling should not be required in the Permit for the Old Outfall treatment
system. Accordingly, the River monitoring requirements in section A.(5.) should be removed.3
Third, section A.(5.) lists four compounds (DFSA, MMF, MTP, and PPF Acid) under the
Table 3+ Lab SOP analytical method. However, as previously discussed with DEQ and as noted
in prior submissions to DEQ,4 these four compounds have been removed from the Table 3+ Lab
SOP because that analytical method did not provide accurate data quantifications for those
compounds. Chemours is working with external laboratories on analytical method development
and finding an appropriate testing methodology for these four compounds. Accordingly, section
A.(5.) of the Permit should be revised so that monitoring for these four compounds is not
required until an appropriate testing methodology is established.
Finally, Chemours requests that DEQ add a provision to the Permit allowing Chemours to
apply to DEQ for modifications of the PFAS monitoring requirements, based on monitoring
results or analytical method changes.
3 If the River monitoring requirements in section A.(5.) were to be included in the final Permit, the Downstream
location should be changed to the autosampler located near the Tar Heel Ferry Road Bridge. The Downstream
location listed in the Draft Permit ("The boat ramp approximately 4500 feet downstream at Prospect Hall Landing")
may be an artifact from prior maps of the area, as the location 4500 feet downstream of the Old Outfall does not
contain a boat ramp and both banks of the River there are heavily wooded with no access available from land.
4 See Submission Pursuant to Consent Order Paragraph I I- June 10, 2019; Laboratory Analyses for MTP, MMF,
DFSA and PPF Acid - June 18, 2019; and Updates to Laboratory Analytical Test Methods - June 10, 2020; available
at https://www.chemours.com/en/about-chemours/global-reach/fayetteville-works/compliance-testing.
El

If you have any questions about these comments, please contact me at
[e-mail].
Sincerely,
9,*A, 0 /7
Brian D. Long
Plant Manager
Chemours — Fayetteville Works