NC0020737_Comments_20240108

SOUTHERN
LAW ENVIRONMENTAL
CENTER
Via Mail and Electronic Submission
Nick Coco
Environmental Engineer
NCDEQ-DWR
Water Quality Permitting Section
1617 Mail Service Center
Raleigh, NC 27699-1617
48 Patton Avenue, Suite 304 Telephone [phone]
Asheville, NC 28801 Facsimile 828-258-2024
January 5, 2024 RECEIVED
JAN 0 8 2024
NCDEQ/DWR/NPDES
Re: Comments on NPDES Wastewater Permit NCO020737 Pilot Creek WWTP
Dear Mr. Coco,
Thank you for the opportunity to comment on the draft NPDES Wastewater Permit
NCO020737 for the Pilot Creek Wastewater Treatment Plant (the "Draft Permit"). We submit these
comments on behalf of the Southern Environmental Law Center ("SELC"), MountainTrue, and
the Broad Riverkeeper.
We appreciate the hard work that DEQ put into crafting the Draft Permit and creating the
opportunity for public comment. We especially appreciate DEQ's efforts to address PFAS
pollution by inserting testing and reduction requirements into the Draft Permit. As currently
constituted, the Draft Permit requires the City of Kings Mountain (the "City" or "Permittee") to
collect PFAS monitoring data from industrial users and update the permits for these industrial
users "to address PFAS discharges."' These data must be collected relatively quickly and must be
shared in publicly available pretreatment reports. Together, these provisions will go a long way
toward reducing PFAS pollution in the Buffalo Creek watershed.
Other portions of the Draft Permit, however, do not do enough to protect the existing uses
of Buffalo Creek, as well as downstream environmental justice communities. These shortcomings
must be addressed in a revised permit.
I. DEQ must account for background conditions.
Binding federal regulations require DEQ to determine if a discharge "will cause, have the
reasonable potential to cause, or contribute to an excursion above any State water quality standard,
including State narrative criteria for water quality."' Put differently, DEQ must analyze "whether
a discharge, alone or in combination with other sources ofpollutants to a waterbody ... could lead
' Draft Permit at 13.
2 40 C.F.R. § 122.44(dx1)(i) (emphasis added); see also 15A N.C. Admin. Code 02B .0203 (requiring DEQ to
design "[w]ater quality based effluent limitations and management practices for direct or indirect discharges of
waste ... such that the water quality standards and best usage of receiving waters and all downstream waters will
not be impaired").
Charlottesville Chapel Hill Atlanta Asheville Birmingham Charleston Nashville Richmond Washington, DC

to an excursion above an applicable water quality standard."3 To that end, DEQ must first
"determine the critical background concentration of the pollutant of concern in the receiving water
before the discharge ... to ensure that any pollutant limitations derived are protective of the
designated uses" for those waters.'
Despite the clear requirement and need to analyze background conditions, DEQ's Draft
Permit declines to do so. Instead, it assumes that background concentrations of "all toxicants
except" ammonia are "zero."' That is a questionable assumption. Directly upstream of the outfall
is another permitted facility using chlorine for water treatment.6 Also located upstream within the
upper Buffalo Creek watershed are more than fifty permitted residual solids disposal sites for
various towns and cities.' Many of these permits allow for land application of solid wastes
containing heavy metals and toxic pollutants, including arsenic, cadmium, copper, lead, mercury,
molybdenum, nickel, selenium, and zinc.8 At least some of this pollution is likely washing
downstream during residual application, irrigation, and storm events.
DEQ must redo its reasonable -potential analyses to account for background pollution
levels.9 DEQ has effectively acknowledged as much, noting that it is engaged in "on -going"
discussions with EPA about "how best to address background concentrations." 10 One simple
solution would be to sample in -stream pollution levels just upstream of the outfall." If DEQ is
unsure about how to incorporate this information into its reasonable -potential analyses, EPA's
Permit Writers' Manual provides several suggested approaches for incorporating "background in -
stream pollutant concentration[s]" into a reasonable -potential determination.12
II. DEQ must analyze whether a temperature limit is appropriate.
North Carolina law provides that the temperature of Buffalo Creek, as class C mountain
waters, is "not to exceed 2.8 degrees C (5.04 degrees F) above the natural water temperature, and
in no case to exceed 29 degrees C (84.2 degrees F)."13 This standard has two parts —a delta limit
'U.S. EPA, NPDES Permit Writers' Manual at 6-23 (2010) [hereinafter "Permit Writers' Manual"]; see also 40
C.F.R. § 122.44(d)(lxii) (requiring DEQ to "account for existing controls on point and nonpoint sources of
pollution" in the waterbody when conducting a reasonable -potential analysis).
4 Permit Writers' Manual at 6-19.
5 Fact Sheet at 37.
6 NPDES Permit No. NC0079740 (Dec. 7, 2018),
https:Hedocs.deq nc.gov/WaterResources/DocView.aspx?id=777598&dbid=0&repo=WaterResources&searchid--95
9657c4-ff17-465b-a3b5-427e40486e50.
N.C. Dep't of Env't Quality, DWR Permits Map, https://data-ncdenr.opendata.arcgis.com/apps/ncdenr::penmits-
map/explore.
B See, e.g., NPDES Permit No. WQ0001793 (Dec. 18, 2020),
https://edocs.deq nc.gov/WaterResources/DocView.aspx?id=1401016&dbid=O&repo=WaterResources&searchid=ff
fl bc7f-2669-4b61-bb01-c56074daabfc.
9 Testing for in -stream hardness upstream of the discharge cannot fill this void, since only certain metals are
hardness dependent.
10 Fact Sheet at 37.
" We recommend sampling on Buffalo Creek downstream of the confluence with Muddy Fork and Potts Creek.
Sampling on Buffalo Creek above the confluence would inappropriately skew the result by omitting potential
pollutants contributed by Muddy Fork and Potts Creek.
12 Permit Writers' Manual at 6-23 to -31.
13 15A N.C. Admin Code 02B .0211(18).
2

and an absolute limit. The delta limit prohibits an increase attributable to a "direct or indirect"
discharger of more than 2.8 °C above the natural water temperature.14 It does not require the
discharger to release "heated" liquids specifically; rather, it broadly prohibits dischargers from
adding effluent that increases the "natural" water temperature of the stream above a certain
threshold. 15 Likewise, the absolute limit provides that temperature shall "in no case" exceed
29 °C—regardless of whether thermal dischargers are present.16 Therefore, both of these limits
apply to the Pilot Creek discharge —as DEQ impliedly concedes.17
Yet DEQ's Draft Permit includes no temperature limit. Instead, it only requires daily
monitoring and reporting.18 The Fact Sheet suggests this is because downstream temperatures were
never more than 2.8 °C above upstream temperatures 19 and downstream temperatures never
exceeded 29 °C during the study period. However, the Fact Sheet does not contain a reasonable -
potential analysis to support this argument. What's more, the values the Fact Sheet does report
suggest that the City may be bumping up against both limits; downstream temperatures were 1.5 °C
higher on average and the maximum downstream temperature topped 28 'C. Given these high
values, it seems likely that a predictive analysis of the Pilot Creek discharge would show it has
"the reasonable potential to cause, or contribute to an excursion above" the state temperature
standard.20 DEQ must conduct this analysis in a revised draft permit.
III. DEQ should reevaluate its approach to total residual chlorine.
North Carolina's acute limit for total residual chlorine is 17 ug/L.21 The Draft Permit
acknowledges this limit and sets a daily maximum limit of 28 ug/L across all flow levels to protect
against acute toxicity.22 Nevertheless, the Draft Permit goes on to say that DEQ "shall consider all
effluent total residual chlorine values reported below 50 ug/L to be in compliance with the
permit."23 Apparently, this is because of "analytical issues" with analyzing chlorine levels below
14 Id. 02B .0203 ("Water quality based effluent limitations and management practices for direct or indirect
discharges of waste or for other sources of water pollution shall be developed by the Division such that the water
quality standards and best usage of receiving waters and all downstream waters will not be impaired.").
15 For example, if the natural water temperature of a stream is 15 °C, and a discharger adds "room temperature"
effluent (around 20 °C) to that stream, the temperature of the receiving waters will increase. While the discharger
may not be deliberately heating the receiving waters, the result is the same.
16 15A N.C. Admin Code 02B .0205 ("The adopted water quality standards relate to the condition of waters as
affected by the discharge of sewage, industrial wastes, or other wastes including those from nonpoint sources and
other sources of water pollution.").
" See Fact Sheet at 4.
'$ Draft Permit at 3, 5, 7.
19 This may be a product of DEQ's sample design. According to the Fact Sheet, the downstream sampling site is 2.4
miles downstream of the outfall. Fact Sheet at 3. That is an extremely generous mixing zone.
20 In its reasonable -potential analyses of metal toxicants, DEQ consistently predicted that the maximum likely
concentration value was higher than the maximum recorded value; it is hard to see why temperature should be
treated any differently.
21 15A N.C. Admin. Code 02B .0211(3).
22 Draft Permit at 3, 5, 7.
23 Id. at 4, 6, 8.

50 ug/L.24 Due to these issues, DEQ has been inserting similarly capacious language into NPDES
permits since at least 2008.
DEQ should assess if its 15-year-old assumptions are outdated. In the intervening years,
scientists have developed numerous technologies to better assess chlorine concentrations and
eliminate interference.25 DEQ has also hinted that analytical difficulties no longer prevent accurate
measurements of chlorine below 50 ug/L.26 In fact, DEQ's Fact Sheet for Pilot Creek lists thirty-
five different violations of the 28 ug/L standard over the past five years —indicating that analytical
difficulties may not prevent accurate measurements below 50 ug/L.27 If that is the case, it is unclear
why DEQ is continuing to allow exceedances of the permitted residual chlorine level. After all,
DEQ lacks the authority to issue NPDES permits that do not ensure compliance with water quality
standards, including the total residual chlorine standard.28
DEQ must either explain in a revised draft permit and fact sheet why its de facto 50 ug/L
limit remains necessary or enforce North Carolina's actual standard for total residual chlorine.
IV. DEQ must set a chronic permit limit for silver.
When DEQ determines "that a discharge causes, has the reasonable potential to cause, or
contributes to an in -stream excursion above the allowable ambient concentration of a State numeric
criteria within a State water quality standard for an individual pollutant, the permit must contain
effluent limits for that pollutant."29 DEQ has no authority to issue NPDES permits that do not
ensure compliance with water quality standards.30 Where draft permits fail to ensure compliance,
they must be revised.
DEQ must revise the Draft Permit to include a chronic limit for silver. The chronic standard
for silver in class C waters is 0.06 ug/L .31 Data submitted by the City show that the facility's
' Fact Sheet at 5; see also N.C. Dep't of Env't & Nat. Res., Total Residual Chlorine SO ug/L Compliance Level
(May 1, 2008), https://www.deq nc.gov/coastal-management/gis/data/esmp-data/2010/july/npdes/trccomplevel-
20090710-dwq-swp-npdes/download.
21 See, e.g., Robert Wilson et al., Continuous Chlorine Detection in Drinking Water and a Review of New Detection
Methods, 63 Johnson Matthey Tech. Rev. 103 (2019); Peng Li, Concise Review on Residual Chlorine Measurement:
Interferences and Possible Solutions, 323 J. of Cleaner Prod. (2021); Peng Li. et al., Micro particles as Interfering
Substances in Colormetric Residual Chlorine Measurement, 207 Ecotoxicology & Env't Safety (2021); Vt. Dep't of
Env't Conservation, Chlorine Residual,
https:Hdec.vermont.gov/sites/dec/files/wsm/wastewater/docs/Section%209_Total%20Residual%20Chlorine.pdf
(describing low -range colorimetric analyses with a range of 2 to 500 ug/L)
I See Compliance Evaluation Inspection Report, NPDES Permit No. NCO020737 (Mar. 24, 2022) (criticizing Pilot
Creek's failure to show its chlorine curve could meet the low chlorine limit of 10 ug/L)
27 Fact Sheet at 40-42.
28 See 33 U.S.C. § 131 l(b)(l)(C) (requiring NPDES permits to include limitations "necessary to meet water quality
standards"); 40 C.F.R. § 122.44(d)(1) (same).
29 40 C.F.R. § 122.44(d)(1 xiii) (emphasis added); see also Permit Writers' Manual at 6-31 ("If a permit writer has
determined that a pollutant or pollutant parameter is discharged at a level that will cause, have reasonable potential
to cause, or contribute to an excursion above any state water quality standard, the permit writer must develop
WQBELs for that pollutant parameter.").
30 See 33 U.S.C. § 1311(b)(1)(C) (requiring NPDES permits to include limitations "necessary to meet water quality
standards"); 40 C.F.R. § 122.44(d)(1) (same).
31 15A N.C. Admin. Code 02B .0211(11Xd).
U

effluent topped out at 1.8 ug/L on April 15, 2021—thirty times the state standard.32 Though this
effluent is diluted by the receiving waters, DEQ's reasonable -potential analysis suggests it will not
be diluted enough. Using that analysis, DEQ calculated that the City's effluent must contain no
more than 0.305 ug/L to meet the chronic standard; however, its analysis predicted a maximum
effluent value of 4.325 ug/L.
Because DEQ not only had evidence that the City's discharge causes excursions, but also
has the reasonable potential to cause future excursions, it should have imposed a chronic silver
limit. Instead, it purported to exercise its `BPJ"33—best professional judgment34—and required
quarterly monitoring instead. However, DEQ lacks the discretion to ignore the City's data and the
agency's own reasonable -potential analysis.35 It is required, as a matter of law, to impose a chronic
silver limit.
V. DEQ must employ the current chronic standard for selenium.
Current water quality standards for class C waters include a multi -component chronic
standard for selenium.36 In the following order of preference, DEQ must assess compliance using:
(1) fish egg/ovary tissue; (2) fish whole body or muscle tissue; or (3) water column
concentrations.37 Water -column concentrations are further divided into lentic and lotic standards
of 1.5 ug/L and 3.1 ug/L, respectively, which much be assessed using a 30-day average.38
DEQ did not assess compliance with this updated standard in the Draft Permit. Instead, it
mistakenly used the old 5 ug/L chronic standard in its analysis.39 Accordingly, it must redo its
selenium analysis.
It is unclear if the Permittee's reported data comply with the current standard. Based on the
Fact Sheet, it seems that the City sampled for selenium using water -column concentrations.
However, the Fact Sheet does not explain whether these samples were 30-day averages as the
regulation requires. DEQ must follow-up with the Permittee to determine whether their samples
post-dating the June 1, 2022 amendment to the selenium standard comply with that standard.
If DEQ has no useable data with which to assess compliance with the new selenium
standard, DEQ should engage in the qualitative approach suggested by EPA in its Permit Writers'
Manual .40 In the Manual, EPA recommends crafting a water -quality -based effluent limit by
assessing, among other factors, whether (1) the permittee has a "history of compliance problems
and toxic impacts"; (2) "[p]oint and nonpoint source controls" in the watershed; (3) "[s]pecies
32 Fact Sheet at 25.
33 Id. at 30.
34 In the Clean Water Act context, "best professional judgment" is a statutory and regulatory standard for crafting
certain technology -based effluent limitations, among other limits. See, e.g., 40 C.F.R. § 125.3(ax2)(i)(B). It is not a
"magic" phrase that allows DEQ to avoid setting permit limits.
31 See 33 U.S.C. § 1311(bx1)(C); 40 C.F.R. § 122.44(dxl)(iii).
36 15A N.C. Admin. Code 0213.0211(11)(d).
37 Id.
38 Id
39 Fact Sheet at 15-17.
41 See Permit Writers' Manual at 6-30 to -3 1.

sensitivity data including in -stream data, adopted water quality criteria, or designated uses"; and
(4) "[d]ilution information such as critical receiving water flows or mixing zones ."41 DEQ should
also consider environmental justice impacts, as explained below.
Vl. DEQ must not backslide on permit limits for molybdenum and selenium.
The Clean Water Act ("CWA") was expressly designed to "eliminat[e] the discharge of all
pollutants."42 To that end, the Act broadly prohibits dischargers seeking a renewed or reissued
permit from backsliding on their previous permit's effluent limits.43 Special circumstances must
be present for a permittee to qualify for an exemption from this anti -backsliding requirement.'
For effluent limitations based on state water quality standards, as is largely the case here,
relaxation of a permit requirement must be consistent with CWA Section 303(d)(4).45 That Section
provides that if water quality standards for the receiving waters are being attained, then the
"permitting standard may be revised only if such revision is subject to and consistent with the
[state's] antidegradation policy."46
North Carolina's antidegradation policy requires DEQ to protect "existing uses" of a water
body.a' This includes both the "present and anticipated usage of waters," including "any uses not
specified by the [waterbody's] assigned classification. ,48 To ensure these uses are not degraded,
both the permittee and DEQ must follow a set of specific procedures.49
DEQ's Draft Permit relaxes permit standards for molybdenum and selenium.50 Because
the previous permit's effluent limitations for these pollutants were based on state water quality
standards, and water quality standards in Buffalo Creek are currently being attained, DEQ may
only relax the molybdenum and selenium standards "if such revision is subject to and consistent
with the [state's] antidegradation policy."51 Yet DEQ expressly declines to conduct an
antidegradation review in the Draft Permit.52 The failure to do so violates the CWA.
Backsliding on the previous permit's selenium limit is particularly inappropriate given the
circumstances here. DEQ suggests that a strict application of its reasonable -potential analysis
would require a permit limit for selenium. In other words, it predicts —based on all of the City's
data that the Permittee is likely to violate the water quality standard for selenium. When that is
41 Id.
4133 U.S.C. § 1311(b).
41Id § 1342(o).
44 Id.
41 Id § 1342(o)(1).
461d. § 1313(d)(4).
4' 15A N.C. Admin. Code 02B .0201(b).
4' Id. 02B .0201(c).
49 Id.
50 Fact Sheet at 9.
51 33 U.S.C. § 1313(d)(4).
sz Fact Sheet at 9.
6

the case, DEQ may not revise a permit to contain a less stringent standard.53 However, DEQ
sidesteps this requirement by identifying a sampling failure. Specifically, DEQ notes that the
Permittee conducted seven of its forty-six selenium samples using an insufficiently sensitive
sampling method,54 which skewed the resulting analysis. Instead of applying the precautionary
principle, DEQ exercises its "best professional judgment" and throws those seven data points out
entirely. With those data removed, DEQ then finds that, under its inappropriately circumscribed
analysis, no selenium exceedances are reasonably likely. In effect, DEQ rewards the Permittee for
conducting inadequate testing by removing permit limits for selenium. That is not an appropriate
use of the agency's "best professional judgment" —especially given the presence of environmental
justice communities in the watershed.
VII. DEQ should consider the environmental justice impacts of the Draft Permit.
Governor Cooper's Executive Order 292 requires cabinet agencies —including DEQ—to
incorporate environmental justice considerations into their decision -making and "consider public
health impacts in their permitting, policy actions, and agency programs to the furthest extent
permissible by law."55 According to the state's community mapping tool, two environmental
justice communities are located downstream of the outfall.56 Both of these communities have
significantly higher rates of cancer, heart disease, and child mortality than the state average.57
Because communities like these are often disproportionately affected by chemical and
nonchemical pollution, E.O.292 requires DEQ to carefully assess whether its permitted limits are
acting as cumulative stressors. This means the agency must analyze background conditions, as
explained above, and err on the side of caution when setting permit limits. For example, even if
DEQ concludes that it is technically permitted to backslide on molybdenum and selenium limits
after conducting its required antidegradation analysis,58 DEQ should still think twice about
greenlighting such backsliding, knowing that two environmental justice communities may be
cumulatively impacted by any increased pollution.
VIII. Conclusion
DEQ must revise the Draft Permit and reissue it for public comment. Thank you for
consideration of this letter. Please contact or Alyson Merlin (828-258-2023; [e-mail]),
or Spencer Scheidt (828-258-2023; [e-mail]) if you have any questions regarding
these comments.
53 33 U.S.C. § 1342(oX3) ("In no event may such a permit to discharge into waters be renewed, reissued, or
modified to contain a less stringent effluent limitation if the implementation of such limitation would result in a
violation of a water quality standard ....")
54 Fact Sheet at 7.
ss Exec. Order 292 (Oct. 24, 2023).
s6 See N.C. Dep't of Env't Quality, Community Mapping System,
https://ncdenr.maps.arcgis.r,om/apps/webappviewer/index html?id=lebOfbe2bcfb4cccb3cc212af8a0b8c8.
57 Id
58 See supra.
7

Sincerely,
(4 -
Alyson Merlin, Associate Attorney
Southern Environmental Law Center
Spencer Scheidt, Associate Attorney
Southern Environmental Law Center
David Caldwell, Broad Riverkeeper
MountainTnre