NC0004987_DRAFT Permit Comments_20220211

SOUTHERN
ENV RONMENTAL
CENTER
Via Electronic Mail and U.S. Mail
48 Patton Avenue, Suite 304 Telephone [phone]
Asheville, NC 28801 Facsimile 828-258-2024
February 11, 2022
N.C. Department of Environmental Quality
NPDES Permitting Branch
c/o Sergei Chernikov
1617 Mail Service Center
Raleigh, North Carolina 27699-1617
[e-mail]
Re: Draft NPDES Permit NC0004987
Dear Dr. Chernikov:
Please accept these comments on behalf of the Catawba Riverkeeper Foundation, the
Sierra Club, and the Southern Environmental Law Center concerning the renewal of NPDES
Permit No. NC0004987 for Duke Energy's Marshall Steam Station in Terrell, NC.
The Catawba Riverkeeper Foundation's primary mission is to protect the 8,900 miles of
waterways in the Catawba—Wateree River Basin. The Foundation fulfills its mission through
monitoring, conservation advocacy, and public education and engagement. The Foundation's
members routinely use rivers and lakes within the watershed for recreation; some members rely
on the river as a drinking water source, others for educational and business purposes. The
Foundation also has members that live on Lake Norman in the vicinity of the Marshall Steam
Station. Sierra Club, founded in 1892, is the nation's oldest and largest grassroots nonprofit
environmental organization, with over 15,000 members and supporters in North Carolina. Sierra
Club's purposes are to explore, enjoy, and protect the wild places of the Earth; to practice and
promote the responsible use of the Earth's ecosystems and resources; to educate and enlist
humanity in the protection and restoration of the quality of the natural and human environment;
and to use all lawful means to carry out these objectives. The Southern Environmental Law
Center works to protect the basic right to clean air, clean water, and a livable climate; to preserve
the South's natural treasures and rich biodiversity; and to provide a healthy environment for all.
The Foundation, Sierra Club, and the Southern Environmental Law Center all have a long history
of identifying environmental problems at the Marshall Steam Station and working towards
solutions.
There are several fundamental problems with the NPDES permit as drafted. Many of
these stem from overreliance on the Reasonable Potential Analysis and water quality -based
effluent limitations. Namely:
• The Draft Permit relies on the Reasonable Potential Analysis ("RPA") to relax
various permit requirements in violation of the anti -backsliding provisions of the
Clean Water Act ("CWA"), which require that a new or modified permit contain
Charlottesville Chapel Hill Atlanta Asheville Birmingham Charleston Nashville Richmond Washington, DC

limits and conditions at least as stringent as those in the previous permit except in
limited circumstances.
• DEQ also relies on the RPA to displace the necessary implementation of technology -
based effluent limitations ("TBELs") in violation of the CWA. Application of TBELs
is necessary to fulfill Congress's "goal that the discharge of pollutants into the
navigable waters be eliminated." 33 U.S.C. § 1251(a)(1).
In addition to this overreliance on water quality -based effluent limitations ("WQBELs"), the
Reasonable Potential Analysis itself is flawed and fails to accurately represent the discharges
from Outfalls 002 and 005. The Draft Permit also fails to address discharges of wastewater
through unpermitted seeps and incorrectly applies North Carolina's water quality standard for
turbidity. The permit cannot be issued in its current form in compliance with the CWA and must
be revised.
I. The Draft Permit Violates the Clean Water Act's Anti -Backsliding Provisions.
The CWA's anti -backsliding provisions require that a new or modified NPDES permit
contain limits and conditions at least as stringent as those of the previous permit at the same
facility. 33 U.S.C. § 1342(o)(1); 40 C.F.R. § 122.44(1)(1) ("[W]hen a permit is renewed or
reissued, interim effluent limitations, standards or conditions must be at least as stringent as the
final effluent limitations, standards, or conditions in the previous permit...). The proposed
permit impermissibly relaxes effluent limits and monitoring requirements for several constituents
discharged by the Marshall Steam Station. Although the CWA contains exceptions to its anti -
backsliding provisions, the Draft Permit neither demonstrates nor alleges that the Marshall
Steam Station falls into any of these exceptions. As such, the terms of the proposed permit
violate the CWA and must be amended. See 33 U.S.C. § 1342(o)(2) (providing exceptions).
A. DEQ Must Strengthen Relaxed Monitoring Requirements in the Draft
Permit.
The Draft Permit improperly weakens many of the monitoring requirements mandated by
the Marshall Steam Station's current, active permit. For Outfall 002, the Draft Permit prescribes
a change from weekly monitoring to monthly monitoring for Copper, Iron, Mercury, Arsenic,
and Selenium. DEQ's assertion that these changes were informed by the results of the RPA, Fact
Sheet at 33, is inapposite, as the CWA does not include an exception to its anti -backsliding
provisions related to that analysis. Equally unavailing is DEQ's reliance on the RPA for the
complete removal of monitoring requirements for Cadmium, Chromium, Iron, Lead, Nickel,
Silver, and Zinc at Outfall 005. Id. The CWA and its implementing regulations explicitly
prohibit issuance of new standards and conditions which are less stringent than a facility's
previous permit, and no exception applies here. See 33 U.S.C. § 1342(o)(1); 40 C.F.R. §
122.44(1)(1). DEQ's own explanation fails to acknowledge these anti -backsliding provisions.
Removal of monitoring requirements is particularly problematic where the waste stream
is undergoing a change and has effectively not been monitored in the past —as is the case with
Outfall 002, which is transitioning from discharging "decanted" wastewater from the ash pond to
"dewatering" wastewater. Draft Permit at 4. This outfall also may be newly discharging
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"extracted groundwater from remediation activities." Id. at 2. DEQ implicitly acknowledges that
it does not have perfect information about this waste stream by requiring Duke Energy to "treat
the wastewater discharged from the ash pond/ponds using physical -chemical treatment, if
necessary, to assure state Water Quality Standards are not contravened." Id. at 5. This
requirement only works if Duke Energy has some indication that state water quality standards
may be contravened —which requires monitoring. If the constituents of a new waste stream
created by switching from decanting to dewatering are unknown, monitoring frequency should
be increased rather than decreased.
DEQ must also explain how it will enforce daily maximum and monthly average effluent
limitations where only monthly monitoring is required. For example, at Outfall 005, discharges
of Total Suspended Solids ("TSS") are limited to a 50.0 mg/L daily maximum and 30.0 mg/L
monthly average —but TSS is subject to only monthly monitoring.' DEQ must explain how daily
maximum and monthly average limits will be enforced if the Marshall Steam Station is only
required to monitor its discharge once per month. As another example, at Outfall 006, discharges
of Arsenic, Mercury, Selenium, and Nitrate are subject to monthly average and daily maximum
limits but monitoring is only required once per quarter. Draft Permit at 9. If the monitoring
program is inadequate to detect permit violations, it cannot ensure permit compliance —thereby
failing to protect receiving waters in accordance with the requirements of the CWA. We urge
DEQ to clarify its monitoring system or amend this oversight in the final permit.
B. DEQ Must Amend Weakened and Eliminated Effluent Limitations in the
Draft Permit.
The Draft Permit also contravenes the CWA by proposing to raise or eliminate certain
constituent effluent limitations. At Outfall 005, the Draft Permit transforms the limits on Copper
from WQBELs to TBELs based on the results of the RPA, Fact Sheet at 33, but DEQ's new
TBEL allows a greater quantity of Copper to be discharged from the facility than the previous
WQBEL (moving from a monthly average limit of 68.8 µg/L and daily maximum of 76.8 µg/L
to a proposed monthly average and daily limit of 1.0 mg/L). The CWA does not permit such an
increase in discharge during permit renewal, and DEQ's reliance on the RPA fails to justify
infringement of the CWA's anti -backsliding provisions.
More problematically, the Draft Permit proposes to eliminate the effluent limits for three
constituents at Outfall 002 entirely. Although Arsenic has a monthly average limit of 139.1 µg/L
and a daily maximum of 695.4 µg/L in the active permit, the Draft Permit would eliminate those
limitations entirely. DEQ again purports to rely on the results of the RPA for this decision. Id. at
32. As discussed above, the RPA is not, nor can it be contorted to become, an exception to the
CWA's anti -backsliding provisions.
The Draft Permit also eliminates the effluent limitations for Copper and Iron from Outfall
002. According to the active permit, these limits only apply "when chemical metal cleaning
1 The TSS requirement at Outfall 002 similarly includes monthly average and daily maximum limitations but
purports to require only monthly monitoring. Draft Permit at 4. This appears to be in tension with another provision
of the permit stating: "The facility shall continuously monitor [TSS] concentrations and the dewatering pump shall
be shut off automatically when one half of the Daily Maximum limit (15 minute average) is exceeded." Id. at note 2.
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wastewaters are being discharged." Permit at 7, note 3. In this context, we assume "discharged"
means discharged into Lake Norman, and not discharged into the ash basin which is designed to
have a 30-day retention time, Fact Sheet at 2—it would make little sense to apply limits to the
outfall when waste is put into the ash pond but not when it is discharged out of it. To justify the
removal of the Copper and Iron limits, DEQ notes that the ash basin no longer receives
wastewater. Id. at 33. DEQ has not alleged that this change meets one of the statutory exceptions
to the CWA's anti -backsliding provisions at 33 U.S.C. § 1342(o)(2)—which is required to
eliminate this limit Moreover, it has not been shown that the elimination of chemical metal
cleaning wastewater input to the ash pond will end discharges of Iron and Copper through
Outfall 002. To the contrary, the permit renewal application (hereinafter "NPDES Renewal
Application") notes that both Cooper and Iron are "believed present" in the discharge from
Outfall 002. See NPDES Renewal Application, Form 2C for Outfall 002, at 11-24. If Iron and
Copper will continue to be discharged through Outfall 002, DEQ should retain the existing
limits
II. The Permit Must Be Revised to Include Technology -Based Effluent Limitations.
A. Site -Specific TBELs Must Be Based on The Best Available Technology.
All NPDES permits must contain TBELs. 40 C.F.R. § 125.3(a); U.S. ENV'T PROT.
AGENCY, NPDES PERMIT WRITERS' MANUAL, § 3.2 (Sept. 2010) (hereinafter Permit Writers'
Manual).2 Where TBELs are inadequate to achieve water quality standards, the permit must also
include WQBELs. 40 C.F.R. § 122.44(d); see generally Permit Writers' Manual, Chapter 6.
TBELs are the first line of defense and must be implemented even if they are more protective
than required under WQBELs. 15A N.C. Admin. Code 2B.0404(a) ("if the discharge is subject
to both technology based and water quality based effluent limitations for a parameter, the more
stringent limit shall apply"); see Permit Writers' Manual at 5-1. Here, TBELs must be based on
the best available technology economically achievable ("BAT") to control and, if possible,
eliminate the discharge of pollutants. 33 U.S.C. § 1311(b)(2)(A). Congress made the Act
"technology -forcing": technology -based effluent limitations spur innovation in wastewater
treatment and control and ensure progress toward the Act's goal of eliminating the discharge of
pollutants into navigable waters. Kennecott v. EPA, 780 F.2d 445, 448 (4th Cir. 1985); see also
EPA v. Nat'l Crushed Stone Ass'n, 449 U.S. 64, 74 (1980).
TBELs in NPDES permits are derived in one of two ways — either from Effluent
Limitation Guidelines ("ELGs") issued by the Environmental Protection Agency ("EPA") for the
relevant discharging industry, 33 U.S.C. § 1314(b), or where no ELG applies, from the "best
professional judgment" ("BPJ") of the permit writer after a case -by -case analysis, 40 C.F.R. §
125.3(c)(2). If an ELG partially applies to some pollutants or activities in the permit application,
those pollutants or activities not covered are subject to the permit writer's BPJ. 40 C.F.R. §
125.3(c)(3).
ELGs were promulgated for the Steam Electric Power Generating Point Source Category,
which includes the Marshall Steam Station, for specific waste streams in 1974, 1977, 1982, and
relevant here, in 2015. The 2015 rule established ELGs for seven waste streams: FGD
2 https://www.epa.gov/sites/production/files/2015-09/documents/pwm 2010.pdf.
4

wastewater, fly ash transport water, bottom ash transport water, FGMC wastewater, gasification
wastewater, nonchemical metal cleaning wastes, combustion residual leachate, and legacy
wastewater. See 80 Final Rule, Effluent Limitations Guidelines and Standards for the Steam
Electric Power Generating Point Source Category, Fed. Reg. 67,838, 67,849 (Nov. 3, 2015). The
rule defined "legacy wastewater" as "FGD wastewater, fly ash transport water, bottom ash
transport water, FGMC wastewater, or gasification wastewater generated prior to" a specific
date. Id. at 67,854. Combustion residential leachate was defined as "liquid, including any
suspended or dissolved constituents in the liquid, that has percolated through or drained from
waste or other materials placed in a landfill, or that passes through the containment structure
(e.g., bottom, dikes, berms) of a surface impoundment." Id. at 67,847.
For legacy wastewater and combustion residual leachate, EPA's 2015 rule attempted to
rubber-stamp existing coal ash settling lagoons —the same technology required under EPA's
1982 ELG—as BAT, providing virtually no limits for toxic pollutants in these wastestreams. See
80 Fed. Reg. at 67,854. In 2019, the Fifth Circuit Court of Appeals rejected this approach and
vacated the provisions of the 2015 rule applicable to leachate and legacy wastewater. Sw. Elec.
Power Co. v. EPA, 920 F.3d 999 (5th Cir. 2019). The Fifth Circuit found EPA's decision:
particularly inexplicable given the rule's recognition that impoundments have
proven "largely ineffective" at pollution control over the past decades. And, as we
have seen, it was the recognized shortcomings of impoundments —shortcomings
with respect to leachate discharges as well as other wastestreams—that led the
agency to revise the steam -electric effluent guidelines in the first place.
Id. at 1025-26 (citations omitted).
Almost three years have passed since the Fifth Circuit's vacatur of the leachate and
legacy wastewater portions of the ELG Rule, and EPA has yet to promulgate a new rule
addressing either waste stream. Therefore, the NPDES permit writer must use best professional
judgment to determine the BAT standard applicable to legacy wastewater and leachate
discharges at Marshall Steam Station (and any other discharge not covered by the ELG). 33
U.S.C. § 1342(a)(1)(B); 40 C.F.R. § 125.3; 15A N.C. Admin. Code 2H .0118. When applying
best professional judgment, "[i]ndividual judgments []take the place of uniform national
guidelines, but the technology -based standard remains the same." Tx. Oil & Gas Ass 'n v. EPA,
161 F.3d 923, 929 (5th Cir. 1998).
Notably, EPA itself reached this same conclusion recently. In re GSP Merrimack LLC,
NPDES Appeal Nos. 20-05 & 20-06 (Aug. 3, 2021).3 EPA issues the NPDES permit for the
Merrimack coal-fired plant in New Hampshire. There, the agency initially proposed sending
leachate to an impoundment with no additional treatment. Id. But after the Fifth Circuit's
decision in Southwestern Electric Power Co., EPA has agreed that it must set limits for leachate
discharge according to the best professional judgment of the permit writer. Id. At EPA's motion,
the Environmental Appeals Board remanded that portion of the proposed permit to correct this
3https://yosemite.epa.gov/OA/EAB WEB Docket.nsf/Filings%20By%20Appeal%20Number/CB6DAB631E28A9
A48525 87260066B9C0/$File/GSP%20Merrimack%2OLLC%20(final).pdf
5

error and allow EPA to conduct a site -specific best available technology analysis for treatment of
leachate at Merrimack. Id.
B. The Draft Permit Fails to Limit Known Constituents of Coal Ash Waste
Using the Best Available Technology.
Despite the law's clear requirement, the Draft Permit fails to impose site -specific TBELs
based on the permit -writer's BPJ.
While most internal waste streams are purportedly no longer directed to Outfall 002, it
still discharges "treated wastewater [including] metal cleaning wastes, coal pile runoff, ash
transport water, storm water, low volume wastes, landfill leachate, extracted groundwater from
remediation activities, and [FGD] wet scrubber wastewater." Draft Permit at 2. This is, at least in
part, "legacy wastewater" as defined in the 2015 ELG. See 80 Fed. Reg. at 67,854. Because that
portion of the 2015 rule has been vacated, DEQ must establish and apply TBELs based on the
permit writer's BPJ. The NPDES Renewal Application is clear that a number of contaminants
are "believed present" in this discharge including Antimony, Arsenic, Copper, Mercury, Nickel,
Selenium, Thallium, Bromide, Sulfate, Sulfide, Aluminum, Barium, Boron, Cobalt, Iron,
Molybdenum, and Manganese. See NPDES Renewal Application, Form 2C for Outfall 002 at
11-24. Many of these contaminants are associated with coal ash waste. Nevertheless, Outfall 002
includes virtually no discharge limitations except for one applicable to Oil and Grease and
another applicable to TSS. To DEQ's credit, the Oil and Grease and TSS limits "are based on
Best Professional Judgment" —but they are the only BPJ-based limits in the entire draft permit.
See Fact Sheet at 32 (describing the basis for permit limits).
Outfall 002 also may be discharging waste streams that are not "legacy wastewater" —
namely, contaminated groundwater. As part of the dewatering phase, Outfall 002 will be
discharging groundwater from beneath the ash basin. Draft Permit at 4. While not entirely clear,
the Draft Permit also indicates that "extracted groundwater from remediation activities" is routed
through the ash pond and discharged through Outfall 002. Draft Permit at 2. Processing these
waste streams through Outfall 002 further underscores the importance of using BPJ to establish
TBELs.
The discharge of "extracted groundwater from remediation activities" through Outfall
002 deserves further discussion. First, the Draft Permit references this waste stream only once,
seemingly as an afterthought. DEQ must clearly disclose if this waste stream is being processed
through NDPES outfalls—which should not be allowed absent additional, meaningful treatment
of this contaminated groundwater. The contaminated groundwater is being extracted, in part,
because it is flowing into streams and Lake Norman. In other words, the extraction is intended to
prevent contamination from reaching surface waters. It makes no sense to spend significant
effort and expense extracting this groundwater only to dump it into Lake Norman, with no
further treatment, via the ash pond and Outfall 002—particularly when the ash pond is how this
groundwater became contaminated in the first place.
Second, this practice risks violations of EPA's Coal Combustion Residuals Rule. EPA
has clarified that "monitored natural attenuation," or "MNA," is not an acceptable way to "treat"
6

groundwater contaminated by coal ash. For example, EPA recently explained that "MNA
through dilution and dispersion does not meet the requirements in 40 C.F.R. § 257.97(b)(4) and
is not appropriate for consideration as a primary corrective measure." EPA, Proposed Denial of
Alternative Closure Deadline for Clifty Creek Power Station at 54 (Jan. 22, 2022).4 This and
other EPA rulings explain in detail why MNA does not "remove from the environment as much
of the released contaminated material as feasible as required under 40 C.F.R. §§ 257.97(b)(1)
and (4)." Id. at 60-67. The rulings also discuss preferable alternatives, such as ex -situ treatment
of groundwater contamination. E.g., id. at 56-70.
Pumping contaminated groundwater to the surface and processing it through the ash pond
and Outfall 002 with no further treatment is effectively the same as MNA except that the
insufficient "dilution and dispersion" would occur in surface waters instead of groundwater.
DEQ cannot permit this practice.
Many of the same problems that plague Outfall 002 also apply to Outfall 005. Most
interior waste streams at Marshall Steam Station have now been redirected from the unlined ash
pond, which discharges through Outfall 002, to the lined retention basin which discharges
through Outfall 005. See Draft Permit at 2. The NPDES Renewal Application indicates that
Cadmium, Copper, Mercury, Nickel, Selenium, Bromide, Sulfate, Sulfide, Sulfite, Aluminum,
Barium, Boron, Cobalt, Iron, and Manganese are "believed present" in Outfall 005's discharge.
See NPDES Renewal Application, Form 2C for Outfall 005 at 11-24. Like Outfall 002, Outfall
005 contains no limits on any of these contaminants (except Iron and Copper when "chemical
metal cleaning wastewaters are being discharged"). See Draft Permit at 10. Worse, Outfall 005
has no flow limitation —allowing discharges of wastewater in unlimited quantities.
Based on the language in the Draft Permit and the RPA, these omissions appear to be
based on the erroneous belief that TBELs are unnecessary where water quality standards are
being met. As explained above, WQBELs are intended to supplement TBELs, not supplant them
(and as explained below, the RPA here is flawed). The RPA is intended to inform the
development of WQBELs; it is unrelated to treatment technologies and has no role in the
development of TBELs. The CWA concerns itself with any point source pollutant discharges,
not just with discharges of pollutants that rise to a level that DEQ views as problematic. "The
term `discharge of a pollutant' ... means any addition of any pollutant to navigable waters from
any point source." 33 U.S.C. § 1362(12) (emphasis added); 40 C.F.R. § 122.2. As recognized by
the Fourth Circuit Court of Appeals, the statute covers all additions, "no matter how small." W.
Va. Highlands Conservancy, Inc. v. Huffman, 625 F.3d 159, 166-67 (4th Cir. 2010). DEQ cannot
escape applying TBELs because it believes water quality standards will not be violated.
1. Impoundments are not the Best Available Technology for combustion
residual leachate.
One specific problem associated with Outfall 005 relates to the discharge of coal
combustion leachate. In conducting the mandated analysis of best available technologies and
4 https://www.regulations.gov/document/EPA-HQ-OLEM-2021-0587-0023; see also EPA, Coal Combustion
Residuals (CCR) Part A Implementation, https://www.epa.gov/coalash/coal-combustion-residuals-ccr-part-
implementation (collecting decisions issued under the Coal Combustion Residuals Rule).
7

setting limits accordingly, DEQ cannot determine that the status quo of dumping leachate into an
impoundment is BAT. As the Fifth Circuit acknowledged in striking down the portion of EPA's
2015 ELG failing to appropriately limit leachate discharges, "everything the rule says about the
record of impoundments over the past three decades indicates that their performance in
controlling discharges has been distinctly poor." Sw. Elec. Power Co., 920 F.3d at 1018. The
court further noted that impoundments are "demonstrably inferior to other available
technologies." Id. at 1019. EPA itself stated in its 2015 ELG Rule that impoundments "are
largely ineffective at controlling discharges of toxic pollutants and nutrients." 80 Fed. Reg.
67,840.
EPA laid out the critical failings of impoundments in detail:
Pollutants that are present mostly in soluble (dissolved) form, such as selenium,
boron, and magnesium, are not effectively and reliably removed by gravity in
surface impoundments. For metals present in both soluble and particulate forms
(such as mercury), gravity settling in surface impoundments does not effectively
remove the dissolved fraction. Furthermore, the environment in some surface
impoundments can create chemical conditions (e.g., low pH) that convert
particulate forms of metals to soluble forms, which are not removed by the gravity
settling process.
Id.
Rather, a membrane pollution control technology is now available and effective for
such toxic pollution as leachate, and DEQ must evaluate it as BAT for Marshall Steam Station.
EPA has confirmed the availability of membrane pollution control technology by using it for its
Voluntary Incentive Program limits in 2020, 85 Fed. Reg. 64,673, and reconfirmed in July 2021
when announcing its intention to reexamine its ELG determinations to strengthen them:
"treatment systems using membranes continue to rapidly advance as an effective option for
treating a wide variety of industrial pollution, including from steam electric power plants."5
Moreover, EPA's 2020 ELG Rule record demonstrates membrane technology is in use at three
plants in China, and it has been piloted by at least seven plants in the United States, 84 Fed. Reg.
64,620, 64,632 (Nov. 22, 2019), including by Duke Energy at Belews Creek.6 The technology is
also used in other industries.
Accordingly, membrane technology is "available," as courts have interpreted the term
under the CWA, and should be used in the Marshall Steam Station NPDES permit as BAT for
5 EPA Announces Intent to Bolster Limits on Water Pollution from Power Plants (July 26, 2021),
https://www. epa. gov/newsreleases/epa-announces-intent-bolster-limits-water-pollution-power-plants.
6 DEQ, Belews Creek NPDES Permit Fact Sheet at 3,
https://files.nc.gov/ncdeq/Water%20Quality/NPDES%20Coa1%20Ash/2014%20Duke%20Energy%20Renewals%2
Oand%20Modifications/B elews%20Creek/B elews-W W-Permit-Fact-Sheet-Dec.-2018.pdf.
7 See, e.g., EPA, Notes from Site Visit to Duke Energy's Belews Creek Steam Station on December 13,
2017, Docket ID No. EPA-HQ-OW-2009-0819-7337 ("According to [Duke Energy], the paste encapsulation
technology is well proven over the past several decades in the mining industry for tailings deposition and
underground backfill.").
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leachate. At the very least, DEQ must do more than give its blessing to an impoundment system
that does not meaningfully control toxic pollution and must consider other treatment options.
III. The Reasonable Potential Analysis is Flawed.
As noted above, the lack of limits in the Draft Permit appears to be based on the RPA,
completed to determine "the reasonable potential for toxicants to be discharged at levels
exceeding water quality standards." Draft Permit at 3. Where the analysis showed no reasonable
potential, no limit was included in the draft permit. As we have explained, this approach does not
comply with the CWA, which requires application of TBELs even when WQBELs are
unnecessary. DEQ's approach, however, underscores the importance of completing an accurate
RPA. This one falls short on several fronts.
First, DEQ completed an RPA for Outfall 002 and a separate RPA for Outfall 005, but
neither RPA accounts for the existence of the other discharge. See Draft Permit at 3-4. In other
words, the RPA for Outfall 002 assumes a total discharge from Marshall Steam Station of 3
million gallons per day of wastewater, and the RPA for Outfall 005 assumes a total discharge of
5.1 million gallons per day. Because Outfall 002 and 005 will be discharging simultaneously for
a period of time, the total discharge for the facility is closer to 8.1 million gallons per day, not
including discharges of coal ash contaminants through seeps and groundwater hydrologically
connected to surface waters. The RPA is flawed because DEQ has not accounted for the total
amount of waste coming from Marshall Steam Station.
Second, the RPAs assume "the background concentrations for all parameters ... to be
below detection level." Draft Permit at 3. DEQ knows this is a false assumption. The agency has
collected significant surface water sampling data surrounding the Marshall Steam Station in
connection with analyses required under the Coal Ash Management Act. This data shows
background concentrations for many contaminants are above detection level. For example, Duke
Energy's December 2019 Corrective Action Plan Update for Marshall Steam Station lists
background surface water concentrations for numerous constituents at Table 4-4.8 Additional
background surface water concentrations are provided in Table 3-2 of the Clean Water Act §
316(a) Balanced and Indigenous Community Study Report provided with the renewal application
for this permit. The active NPDES permit also requires instream sampling for some parameters,
and the Draft Permit Fact Sheet acknowledges that some of these constituents are above
detection levels. See Fact Sheet at 31 (distinguishing between instream parameters below
detection levels versus below water quality standards). Elsewhere, Duke Energy has
acknowledged that "[s]urface water receptors downgradient of [Marshall Steam Station]
demonstrate compliance with [surface water] standards, with the occasional exception of
dissolved oxygen, chloride, TDS, arsenic, selenium, cadmium (D), copper (D), and lead (D).
Localized influence from NPDES permitted outfalls are likely contributing to these exceptions."9
In other words, Duke Energy not only has surface water parameter concentration data, but some
of this data indicates contributions to surface water standard violations from the NPDES outfalls.
8 https://files.nc.gov/ncdeq/Coal%20Ash/2019-caps/01 Marshall CAPUpdate FullReport 20191231.pdf
9 Duke Energy, 2018 Comprehensive Site Assessment Update at ES-7 (January 31, 2018) (emphasis added),
available from https://www.duke-energy.com/Our-Company/About-Us/Power-Plants/Ash-
Management/Groundwater-Studies.
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With reliable information in hand, there is no excuse for underestimating risk to water quality by
using inaccurate assumptions in the RPA.
For the same reason, it is unreasonable to complete the RPA "utilizing a default hardness
value of 25 mg/L." Fact Sheet at 3. Duke Energy provided hardness data as part of its NPDES
renewal application. That data indicates mean hardness values in Lake Norman ranging from
13.86-17.01 depending on depth. See Clean Water Act § 316(a) Balanced and Indigenous
Community Study Report (2014-2020), Table 3-2. While 25 mg/L is generally considered to be a
conservatively low hardness value, it appears to be too high for use in this particular instance.
Finally, the RPA does not account for all likely discharges from Outfalls 002 and 005
over the course of this permit. The RPA for Outfall 002 was calculated using 58 data points.
Until relatively recently, most of the discharge through Outfall 002 has been decanting water.
Duke Energy has previously represented that water discharged through decanting has "already
undergone treatment" and is fundamentally different from discharging interstitial water through
ash pond dewatering. See Letter from Harry Sideris, Duke Energy, to Jeff Poupart, DEQ (Sept.
30, 2014). But decanting has now concluded and the water discharged through Outfall 002 under
the new permit will be from dewatering, i.e., "removing the interstitial water." Draft Permit at 4.
If the data used to complete the RPA was collected during the decanting phase, it is not
representative of the dewatering phase. DEQ must take this into account to complete an accurate
RPA.
The same is true of Outfall 005, which discharges from the lined retention pond. The
RPA for Outfall 005 is based on 32 data points, but it is unclear when that data was collected. If
that data does not reflect the expected input of waste into the lined retention pond over the life of
the permit, it does not accurately reflect the likely discharges through Outfall 005 and cannot
gauge whether those discharges will lead to violations of water quality standards.
It is also unclear if either RPA accounts for the discharge of extracted, contaminated
groundwater. Duke Energy appears to have predicted concentrations of "constituents of interest"
in this contaminated groundwater.10 These concentrations must also be considered in any reliable
RPA.
IV. DEQ Must Address Unpermitted Discharges of Contaminants Through
Groundwater.
The CWA is a strict liability statute prohibiting the discharge of any pollutant to a Water
of the United States without a permit. 33 U.S.C. § 1311(a). The Supreme Court recently clarified
that this encompasses the "discharge (from a point source) of pollutants that reach navigable
10 Duke Energy, Corrective Action Plan Update, Table 6-10 (Dec. 31, 2019),
https://files.nc.gov/ncdeq/Coal%20Ash/2019-caps/01 Marshall CAPUpdate_FullReport_20191231.pdf. This
document also states (at Table 6-12) that NPDES permit "modification would be required for the discharge of
treated groundwater." We are not aware that Duke Energy has sought this modification and it does not appear to be
considered in the Draft Permit. The only reference in the Draft Permit to discharging contaminated groundwater is
in the Supplement to Permit Cover Sheet. Draft Permit at 2. Duke Energy must clearly disclose if it plans to
discharge contaminated groundwater through NPDES outfalls and DEQ must take this into account when applying
technology -based and water quality -based effluent limitations.
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waters after traveling through groundwater if that discharge is the functional equivalent of a
direct discharge from the point source into navigable waters." Cty. of Maui, Hawaii v. Hawaii
Wildlife Fund, 140 S. Ct. 1462, 1477 (2020); see Black Warrior River -Keeper, Inc. v. Drummond
Co., Inc., No. 2:16-CV-01443-AKK, 2022 WL 129495(N.D. Ala. Jan. 12, 2022) (applying Maui
to find an unpermitted discharge of acid mine drainage through groundwater violates the CWA).
There are two discharges at the Marshall Steam Station that meet this test —colloquially called
seeps S-1 and S-4. DEQ must take steps in this permit and elsewhere to eliminate these
discharges.
For the past several years, seeps S-1 and S-4 have been subject to the requirements of
Special Order by Consent WQ S17-009 ("SOC") issued by the North Carolina Environmental
Management Committee ("EMC"). The SOC identified four unpermitted seeps at Marshall,
including S-1 and S-4. See SOC, Attachment A. Each seep was found to "exhibit some indication
of the presence of coal ash wastewater," which the EMC found "causes or contributes to
pollution of the waters of this State." SOC if 1(e), (m). The EMC also found that "[d]ecanting of
wastewater performed at Duke Energy's coal ash basins is expected to eliminate or substantially
reduce the seeps from the ash basins at the Duke Energy Facilities." Id.? 1(p). Accordingly, the
SOC required accelerated decanting of the Marshall Steam Station coal ash pond, which
concluded in the fall of 2020. See Duke Energy, Seep Management Plan Amendment to
Corrective Action Plan: Marshall Steam Station, 1-1 (April 2021).11
Following decanting, Duke Energy was required to submit a report explaining whether
the seeps had been "dispositioned" in response to decanting. Dispositioned was defined to mean
a seep (1) "is dry for at least three consecutive quarters," (2) "does not constitute, and does not
flow to, waters of the State or Waters of the United States for three consecutive quarters, (3) "is
no longer impacted by flow from any coal ash basins," or (4) "has been otherwise eliminated."
Id.? 2(c)(3). Seeps that were not dispositioned but remained after decanting would have to be
disclosed in a Seep Characterization Report. Id.? 2(d).
Duke filed its Seep Characterization Report in April 2021 disclosing that seeps S-1 and
S-4 were not dispositioned, Seep Characterization Report at 3-3, i.e., they continued to "exhibit
some indication of the presence of coal ash wastewater." On October 8, 2021, DEQ terminated
the SOC. See Letter from Jeff Poupart, DEQ, to Jessica Bednarcik, Duke (Oct. 8, 2021). Moving
forward, Duke proposes to monitor S-1 and S-4 "on a semiannual basis." Seep Characterization
Report at 3-4.
This brings us back to square one. Before the SOC, Duke was discharging coal ash
wastewater through groundwater hydrologically connected to surface waters in violation of the
CWA. The SOC required accelerated decanting under the theory that decanting would resolve
these contaminated discharges. That has proven untrue for S-1 and S-4. The SOC that
"afford[ed] certain relief to Duke Energy" related to these seeps, SOC J 1(a), has been
terminated —all that remains are continued violations of the CWA.
11 https://desitecoreprod-cd.azureedge.net/_/media/pdfs/our-company/ash-management/211508-marshall-seep-
mgmt-amendment.pdf?la=en&rev=4a56c966b9864675883b08b0b2bf2fd7. The amendments to the Corrective
Action Plan contained in the Seep Characterization Report were required by the SOC to "go to public comment."
SOC 2(d). We are unaware if that occurred.
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Notably, in our comments on the draft SOC, we cautioned that if "decanting does not
achieve the expected results, Duke Energy must be required to take further corrective action and
remediation measures that actually eliminate the seepage of pollutants to state waters from the
coal ash basins." See Letter from Amelia Burnette, SELC, to Bob Sledge, DEQ (Feb. 14, 2018).
That time has arrived. DEQ must require further corrective action through this permit and
elsewhere to eliminate these unpermitted seeps, or the Marshall Steam Station will be in
violation of the CWA.
V. DEQ Continues to Misapply the Turbidity Standard at Marshall.
For multiple permit cycles in a row, DEQ has misapplied its water quality standard for
turbidity at Marshall Steam Station —this permit is no different.
The turbidity standard applicable at Marshall Steam Station is "for lakes and reservoirs
not designated as trout waters, the turbidity shall not exceed 25 NTU." 15A N.C. Admin. Code
2B.0211(21). If "turbidity exceeds these levels due to natural background conditions, the existing
turbidity level shall not be increased." Id. (emphasis added).
Outfall 005 includes no turbidity limits or monitoring requirements whatsoever. At a
minimum, DEQ should add a turbidity monitoring requirement.
Outfall 002 requires turbidity monitoring and states that a "discharge from this facility
shall not cause turbidity in the receiving stream to exceed 50 [NTUs]. If the instream turbidity
exceeds 50 NTU due to natural background conditions, the discharge cannot cause turbidity to
increase in the receiving stream. Therefore, if the effluent measurement exceeds 50 NTU, the
Permittee shall sample ... to demonstrate the existing turbidity level in the receiving waterbody
was not increased." Draft Permit at 4-5.
First, the limit for Lake Norman is 25 NTU—not 50 NTU. 15A N.C. Admin. Code
2B.0211(21). Second, requiring consideration of background levels when the effluent exceeds 50
NTU cannot ensure that turbidity in the receiving stream "shall not be increased" when the
stream exceeds the relevant threshold. Id. If the turbidity level in Lake Norman exceeds 25 NTU
(or 50 NTU as wrongfully required in the Draft Permit), it cannot be increased regardless of the
level of turbidity in the effluent. DEQ must rewrite its permit term to prohibit any increase in
turbidity level in Lake Normal over 25 NTU.
VI. Conclusion
For the foregoing reasons, the Draft Permit is unlawful and must be revised in several
important ways to comply with the CWA. In short:
• Violations of the anti -backsliding provisions of the CWA must be corrected;
• TBELs must be implemented regardless of receiving water quality and the RPA;
• The RPA must be revised to accurately reflect both discharges and receiving water
quality;
• Discharges of wastewater through unpermitted seeps must be stopped; and
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• Errors in the application of North Carolina's water quality standard for turbidity must
be corrected.
We appreciate the opportunity to comment on this permit, and would welcome the opportunity
for further discussion of this matter. Thank you for your consideration.
Sincerely,
F ;,,4,4-
Patrick Hunter
Managing Attorney
[e-mail]
Susannah Knox
Senior Attorney
[e-mail]
Alyson Merlin
Associate Attorney
[e-mail]
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