NC0004979_Hearing Officer Report_20170217

ROY COOPER
` Governor
MICHAEL S.REGAN
•
Secretary
Water Resources S.JAY ZIMMERMAN
Environmental Quality Director
February 17, 2017
MEMORANDUM RECEIVED/NCDEQJDa1R
To: Jay Zimmerman FEB 2 7 2017
-- 4k&--
Water Quality
From: Jim Gregson, Regional Supervisor t` Permitting Section
Water Quality Regional Operations Section
Wilmington Regional Office
Subject: Hearing Officer's Report and Recommendations -
Duke Energy Carolinas, LLC - Draft NPDES Wastewater Permit
Allen Steam Station, Gaston County
On April 8, 2015, I served as the Hearing Officer for the Subject Public Hearing held at the
James Warner Citizen Center, 115 West Main Street, in Lincolnton, NC. The purpose of the
public hearing was to allow the public to comment on the draft NPDES wastewater permits and
draft NPDES stormwater permits for Duke Energy Carolinas, LLC's Allen Steam Station,
Marshall Steam Station and Riverbend Steam Station. Because this was a combined public
hearing, Brad Cole from the Division of Energy, Mineral and Land Resources served as the
hearing officer for the Draft NPDES Stormwater Permits.
The Hearing Officer's Report for the Allen Steam Station NPDES permit includes comments
from the public hearing and two public comment periods. Due to substantial changes in the
draft permit, a second public notice was required by the EPA.
In addition to listening to oral comments at the public hearings, I have reviewed all written
comments received during the first public comment period which ended on May 5, 2015, and
the second public comment period which ended on December 7, 2016. In preparation of this
report I have considered all of the public comments, the public record, and the site visit.
The report has been prepared using the following outline:
I. Site History/ Background
II. Site Visit
III. April 8, 2015, Public Hearing and Comments Summary
IV. November 4, 2016, Public Notice Comments Summary
V. Recommendations
VI. Attachments •
•
•
Nothing Compares;-{.....-
State of North Carolina I Environmental Quality I Water Resources
127 Cardinal Drive Extension,Wilmington,North Carolina 28405
910-796-7386

Hearing Officer Report
April 8, 2015, PUBLIC HEARING — DRAFT NPDES PERMITS FOR
DUKE ENERGY CAROLINAS, LLC TO DISCHARGE WASTEWATER
FROM THE ALLEN STEAM STATION, 253 PLANT ALLEN RD.,
BELMONT, GASTON COUNTY
I. History / Background
Duke Energy's Allen Steam Station is a coal fired steam electric generating facility
located in Gaston County. The station, which began operation in 1957, is a five-unit
facility with a capacity of 1,140 megawatts. The facility is permitted to discharge
wastewater under NPDES Permit No. NC0004979 to the Catawba River and South Fork
Catawba River. The Allen Steam Station has two coal ash basins, an active basin and
an inactive basin totaling approximately 322 acres. The active basin has been in use
since 1973. The inactive basin is located to the north of the active basin. Currently the
active ash basin receives sluiced bottom ash and infrequently fly ash. Since 2009, fly
ash is normally handled dry. The ash basin also receives wastewater flows from
pretreated domestic wastewater, coal pile runoff, landfill leachate,flue-gas
desulfurization, the yard drain sump as well as stormwater. The ash basin has a
permitted outfall (Outfall 002) to the Catawba River.
§ 130A-309.210 of the Coal Ash Management Act of 2014 requires owners of coal
combustion residuals surface impoundments to identify and assess all discharges from
the impoundments and to implement corrective action to prevent unpermitted
discharges from the impoundments to the surface waters of the State. Identification of
discharges includes engineered channels designed or improved for the purpose of
collecting water from the toe of the impoundment (toe drains)., as well as non-
engineered seeps and weeps. One method of proposed corrective action allowed
under the Act is to make application for a National Pollutant Discharge Elimination
System (NPDES) Permit amendment to bring the unpermitted discharge under permit
regulations. A Discharge Assessment Plan for the unpermitted discharges at the Allen
Steam Station was submitted by Duke Energy to the Department on December 30,
2014.
The December 30, 2014, Discharge Assessment Plan identified nine unpermitted seeps
at the Allen Steam Station, including two seeps that account for the flow from the toe
drains. To date five additional non-engineered seeps have been identified. It was
determined that only four of the non-engineered seeps would need coverage under the
NPDES Permit. Flow volume for the combined non-engineered seeps was determined
to be 0.006 MGD. The non-engineered seeps would be incorporated into the NPDES
Permit as Outfalls 102, 108, 108B, and 110. The two seeps that account for the flow
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from toe drains have a total flow volume of 0.0091 MGD and would be incorporated into
the Permit under Outfalls 103 and 104.
A summary of the proposed changes to the NPDES Permits can be found on the Fact
Sheet for NPDES Permit Development in Attachment B.
II. Site Visits
A Site visit was conducted at the Allen Steam Station on April 7, 2015. The site visit
was conducted with Duke Energy staff as well as DWR staff. The site visits focused on
the unpermitted seeps and other wastewater outfalls that are the subject of the Draft
NPDES Permit.
III. April 8, 2015, Public Hearing and Comments Summary
A public hearing was held on April 8, 2015, at 6:00 pm, at the James Warner Citizen
Center, 115 West Main Street, in Lincolnton, NC. The purpose of the public hearing
was to allow the public to comment on the draft NPDES wastewater permits and the
draft NPDES stormwater permits for Duke Energy Carolinas, LLC's Allen Steam Station,
Marshall Steam Station and Riverbend Steam Station. Because this was a combined
public hearing, Brad Cole from the Division of Energy, Mineral and Land Resources
served as the hearing officer for the draft NPDES stormwater permits.
The Hearing Officer's Report for the Allen Steam Station NPDES permit was separated
from the reports for the Marshall Steam Station and the Riverbend Steam Station
NPDES permits because the Marshall and Allen permits were required to have a
second public notice and comment period due to substantial changes in the Draft
Permits.
Notice of the hearing (Attachment E.) was published in the Hickory Daily Record, the
Charlotte Observer, and the Gaston Gazette on March 6, 2015. Additionally, a news
release of the Notice was issued on March 6, 2015, and publication of this notice was
posted on the DEQ, DWR and DEMLR websites. The public comment period closed on
May 5, 2015.
Approximately 86 people attended the public hearing including 24 staff members of the
Division of Water Resources and the Division of Energy, Mineral and Land Resources
and the two hearing officers. A total of 60 individuals signed the attendance sign in
sheets at the hearing (Attachment F. and G.). The hearing officer provided opening
comments and Sergei Chernikov, Ph.D., with the Division of Water Resources gave a
brief overview of the draft NPDES wastewater permits. Bradley Bennett with the
Division of Energy, Mineral and Land Resources then gave a brief overview of the draft
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NPDES stormwater permits. Twenty-four individuals registered in advance of the
hearing to provide oral comments. Speakers were allowed five minutes to comment.
Additional time was provided after everyone that registered to speak was finished. Two
individuals that spoke at the hearing also provided written comments. The list of
speakers is included as Attachment F. The two written comments provided at the public
hearing are included with other written comments in Attachment C.
All speakers were generally opposed to the NPDES Permit Drafts. The following is a
summary by issue area of oral comments received at the public hearing:
• Permits would allow coal ash to leak legally or would make legal polluting that is
subject to criminal charges by the United States Department of Justice.
(Speakers 1, 2, 7, 8, 11, 12, and 16)
Response: § 130A-309.210 of the Coal Ash Management Act (CAMA) of
2014 requires owners of coal combustion residuals surface impoundments
to identify and assess all discharges from the impoundments and to
implement corrective action to prevent unpermitted discharges from the
impoundments to the surface waters of the state. Identification of
discharges includes engineered channels designed or improved for the
purpose of collecting water from the toe of the impoundment (toe drains),
as well as non-engineered seeps and weeps. One method of proposed
corrective action allowed under the Act is to make application for a
National Pollutant Discharge Elimination System (NPDES) permit
amendment to bring the unpermitted discharge under permit regulations.
A Discharge Assessment Plan for the unpermitted discharges at the Allen
Steam Station was submitted by Duke Energy to the Department on
December 30, 2014. The facility identified 12 non-engineered and two toe
drains from the ash settling basin. The two toe drains and four of the non-
engineered seeps were determined to require coverage under the NPDES
Permit. One seep did not need coverage under the permit based on the
low concentration of the constituents associated with coal ash. Three of
the seeps were determined not to discharge to surface waters and one
seep outfall pipe has been grouted and no longer discharges. Sampling for
three of the seeps was not required in the permit because they could be
underwater at higher lake levels and that two other seeps would serve as
representative sampling locations for those three.
• Coal ash should be moved out of the storage ponds and placed in safe lined
storage areas or general comments concerning site clean- up. (Speakers 1, 2, 4,
7, 8, 12, 14, 16, 17, 18, 19 and 23)
Response: §130A-309.213 of the Act required the department to develop a
proposed classification system for all coal combustion residuals surface
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impoundments, including active and retired sites. §130A-309.214 requires
owners of coal combustion residual surface impoundments to submit a
proposed closure plan for the Departments approval. High-risk
impoundments shall be closed no later than December 31, 2019,
intermediate-risk impoundments shall be closed no later than December
31, 2024, and low-risk impoundments shall be closed no later than
December 31, 2029.
• Permits would violate laws that are designed to protect the ground waters of
North Carolina or general groundwater concerns. (Speakers 2, 11, 15, 17, 19,
and 23)
Response: While non-engineered seeps do have the potential to
contaminate both surface water and groundwater, the draft NPDES permit
requires groundwater monitoring be conducted to determine compliance
with current groundwater standards found under 15A NCAC 02L .0202. In
accordance with 15A NCAC 02L .0107, the permit-requires that said
monitoring wells be in place at the compliance boundary, such that the
groundwater within the designated area is sufficiently monitored.
Groundwater standard violations would be investigated and regulated
according to 15A NCAC 02L and the Coal Ash Management Act of 2014.
• Permits should require best available treatment technology (BAT) and/or use
require technology based effluent limits (TBEL). (Speakers 2, 16, and 17)
Response: The draft NPDES permit requires both TBEL limits and BAT
limits in accordance with 40 CFR 423 Steam Electric Power Generating
Point Source Category.
• Permits should require sampling for additional constituents. (Speakers 6, 12, 13,
14, 16, 17 and 21)
Response: The sampling requirements in the draft NPDES permit is based
on the state and federal rules, regulations, and policies. The RPA is
conducted on the 126 parameters in the renewal/ma The state conducts a
Reasonable Potential Analysis (RPA) to determine the need for a
monitoring or limit for a particular constituent. RPA is the statistical
analysis of the effluent data that was approved by EPA. The RPA is
conducted on the parameters that are above detection level and have
appropriate state water quality standard/EPA criteria. The majority of the
parameters in the renewal application are below detection level.
• Seeps should be monitored separately or concerns about unspecified seeps.
(Speakers 2, 16 and 17)
•
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Response: The draft NPDES permit requires regular inspection for new
seeps and monitoring requirement for all identified seeps. The six
identified seeps that require permit coverage would be monitored
separately.
• Specific concerns about PCBs. (Speaker 14)
Response: The draft NPDES permit requires priority pollutant analysis be
conducted once per permit cycle at Outfall 002 (ash pond discharge) and
specifically prohibits the discharge of polychlorinated biphenyl
compounds (Condition A.13).
• Specific concerns about selenium and fish contamination. (Speaker 21)
Response: The draft NPDES permit requires fish tissue monitoring once
every year years and requires submission of the results with the renewal
application. The parameters analyzed include arsenic, selenium, and
mercury.
The public hearing audio file is included as Attachment D.
In addition to the public hearing, DWR received 503 written comments via email and
99 comments via the US Mail during the public comment period. Those comments
are included as Attachment C.
42 of the email comments were received using the following form letter email:
1. Using NPDES permits to approve illegal seeps goes against the Clean Water
Act and our own NC General Statutes.
2. The Clean Water Act requires that the permits include limits based on the
"Best Available Technology"and must eliminate discharges of pollution when
possible. Here, it is possible. Excavating the coal ash from leaking lagoons and
storing it in dry, lined landfills away from public waters, or recycling it for
concrete. DENR's new permits should include a requirement to eliminate the
discharges from these sites by excavating them to lined storage or recycling.
3. Many of the toxic metals listed in the permit have no limits on the amount that
can be discharged for coal ash pollutants like cobalt, boron, strontium, and zinc
that are leaking out of the lagoons, and the limits it has set for arsenic, mercury,
and selenium are too weak. This is not acceptable, DENR must SET STRONG
LIMITS on ALL coal ash pollutants.
4..Monitoring of many discharges is proposed for only twice a year, which is
totally inadequate. Monitoring should be increased to gain an accurate
understanding of the changes in discharges throughout the year.
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Response: The inclusion of the seeps into the NPDES permit is based on
the provisions of the Coal Ash Management Act of 2014 (CAMA). The DWR
has been consulting with EPA in regard to the incorporation of the seeps
into the NPDES wastewater permits. The inclusion of the seeps is
considered an interim measure until the facilities decommission the ash
ponds. Some of the seeps are part of the natural groundwater flow and
might remain at the sites even after the ash ponds are decommissioned.
The permits require Technology Based Effluent Limits for Total Arsenic,
Total Mercury, Total Selenium, and Nitrate/nitrite as N. These limits are
based on the recently updated 40 CFR 423. The permits also include the
requirement to meet the CAMA provisions. The CAMA requires removal of
the ash from the High-Risk and Intermediate Risk impoundments and
disposing of it in the landfills. The Low-Risk impoundments might be
capped in place to prevent the water movement through the ash.
The water quality data from the Catawba River indicates that Duke Facilities
do not cause contravention.of the water quality standards for Arsenic,
Selenium, and Mercury. All three parameters were below detection level
downstream from the Duke Energy facilities on the Catawba River. The fish
tissue analysis also indicates compliance with the state and federal
thresholds.
The permit Water Quality Based Effluent Limits are established in
accordance with the EPA Guidance entitled "Technical Support Document
for Water Quality-based Toxics Control." The limits are established only
.when the particular parameter demonstrates a Reasonable Potential to
exceed the state water quality standard or EPA criterion. The state
conducts a Reasonable Potential Analysis (RPA) to determine the need for
a limit for a particular constituent. RPA is the statistical analysis of the
effluent data that was approved by EPA and is based on the conservative
assumption of the low flow and the highest detected value in the
monitoring data set during the last 5 years of the facility operation. The
RPA is conducted on the 126 parameters (if the parameter is detected) in
the renewal/major modification application submitted by Duke Energy.
The monitoring requirements in the permits are based on the state and
federal rules, regulations, and policies. The established frequency is
sufficient to conduct a valid statistical analysis of the effluent data.
127 comments were received using the following form letter email:
I am concerned about the coal ash pollution, which includes arsenic, mercury,
cobalt, seeping into the Catawba River from Duke Energy's leaking and unlined
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lagoons. The draft permits are unacceptably weak and will not adequately protect
our communities from contaminates in coal ash.
For instance, DENR is proposing to start allowing random, untreated streams of
polluted coal ash wastewater to spew out of Duke Energy's lagoons.
These leaks should be stopped and Duke must be required to clean up their
source—the coal ash—and move it away from our waterways.
Response: The inclusion of the seeps into the NPDES permit is based on
the provisions of the Coal Ash Management Act of 2014 (CAMA). The DWR
has been consulting with EPA in regard to the incorporation of the seeps
into the NPDES wastewater permits. The inclusion of the seeps is
considered an interim measure until the facilities decommission the ash
ponds. The combined seeps flow for operating coal-fired power plants
represents a miniscule portion of the wastewater flow from coal ash
impoundment. For example, combined seep flow from Allen Steam Station
represents only 0.08% of the ash pond discharge, for Marshall this number
is 0.02%. This number is higher at the Riverbend steam station since the
facility ceased operations and rarely discharges from the ash pond. The
chemical composition of the seep discharge is almost identical to the ash
pond wastewater but the pollutant concentrations are generally lower. The
statistical analysis conducted on the effluent from ash ponds and seeps
indicates no Reasonable Potential to contravene state water quality
standards or EPA criteria in the receiving stream.
146 comments were received using the following form letter email:
Please reject the current NPDES permits for Duke Energy's three coal ash power
plants along the Catawba River. I'm concerned because the draft permits would
allow Duke Energy to discharge unlimited amounts of arsenic, mercury, and
selenium into the Catawba River and Mountain Island Lake (a drinking water
supply reservoir). This is unacceptable.
The NPDES permitting program goal is to eliminate pollutant discharges and
these permits do not do that. Please protect our communities from coal ash
pollution.
Response: The permits require Technology Based Effluent Limits for Total
Arsenic, Total Mercury, Total Selenium, and Nitrate/nitrite as N. These
limits are based on the recently updated 40 CFR 423. In order to eliminate
pollutant discharges from the Duke Energy sites, the facilities need NPDES
wastewater permits that establish conditions for ash pond dewatering. The
dewatering is the first step in the ash pond decommissioning, which would
significantly decrease pollutant load to the Catawba River.
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•
153 comments were received using the following form letter email:
Please do not allow Duke Energy to pollute our waterways with toxic coal ash.
The NPDES permits for the three power plants along the Catawba River are
woefully inadequate and I hope that you will reject them. As written, the permits
would not even monitor or report on elements and chemicals that are known to
be associated with coal ash ponds. Also, industrial chemicals have been
permitted to be dumped into the coal ash ponds and Duke should be required to
test for them at outfalls.
These permits cannot simply be a way to allow Duke Energy to keep its coal ash
in leaking, unlined lagoons next to bodies of water. I urge you to reject these
NPDES permits as they do not properly protect our communities.
Response: The monitoring requirements in the permits are based on the
state and federal rules, regulations, and policies. The state conducts a
Reasonable Potential Analysis (RPA) to determine the need for a
monitoring for a particular constituent. RPA is the statistical analysis of
the effluent data that was approved by EPA. The RPA is conducted on the
126 parameters (if the parameter is detected) in the renewal/major
modification application. The RPA is conducted on the parameters that are
above detection level and have appropriate state water quality
standard/EPA criteria. The majority of the parameters in the renewal
applications are below detection level. The permit also contains Plan for
Identification of New Discharges. The Plan has mandatory requirements
for 25 sampling parameters.
In order to eliminate ash lagoons, the facilities need NPDES wastewater
permits that establish conditions for ash pond dewatering. The dewatering
is the first step in the ash pond decommissioning.
•
US MAIL COMMENTS •
99 comments were received via the US Mail using the following form letter:
• Using NPDES permits to approve illegal seeps goes against the Clean Water Act
and our own NC General Statutes.
• Permits do not include a timeline for eliminating this illegal discharge. The leaks
should be stopped, not permitted under a fictional collective seep outfall. DENR
should consider utilizing its own SOC process for getting Duke in compliance
with the law, and not allow these illegal discharges to be permitted under an
NPDES permit.
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• Many of the toxic metals listed in the permit have NO LIMITS on the amount that
can be discharged. DENR should never allow unsafe amounts of arsenic,
mercury, and selenium to be discharged into drinking water supplies. There
needs to be specified limits for all elements and chemicals associated with coal
ash.
Response: § 130A-309.210 of the Coal Ash Management Act of 2014
requires owners of coal combustion residuals surface impoundments to
identify and assess all discharges from the impoundments and to
implement corrective action to prevent unpermitted discharges from the
impoundments to the surface waters of the state. Identification of
discharges includes engineered channels designed or improved for the
purpose of collecting water from the toe of the impoundment (toe drains),
as well as non-engineered seeps and weeps. One method of proposed
corrective action allowed under the Act is to make application for a
National Pollutant Discharge Elimination System (NPDES) permit
amendment to bring the unpermitted discharge under permit regulations.
A Discharge Assessment Plan for the unpermitted discharges at the Allen
Steam Station was submitted by Duke Energy to the Department on
December 30, 2014. The facility identified 12 non-engineered and two toe
drains from the ash settling basin. The two toe drains and four of the non-
engineered seeps were determined to require coverage under the NPDES
Permit. One seep did not need coverage under the permit based on the
low concentration of the constituents associated with coal ash. Three of
the seeps were determined not to discharge to surface waters and one
seep outfall pipe has been grouted and no longer discharges. Sampling for
three of the seeps was not required in the permit because they could be
underwater at higher lake levels and that two other seeps would serve as
representative sampling locations for those three. Incorporation of the
seeps in to the NPDES permit is considered an interim measure until the
coal ash impoundments are closed. The draft permit requires that the.
facility continue to implement a plan for the identification of new seeps. A
• seep identification survey shall be conducted semi-annually and new seeps
are to be reported to the Division within five days of detection.
Special Orders by Consent (SOC) can be an appropriate action when a
facility is unable to consistently meet terms, conditions or limits in an
NPDES permit. In this case, there is no evidence that Duke Energy will be
unable to meet the proposed effluent limits.
The Division conducted EPA-recommended analyses to determine the
reasonable potential for toxicants to be discharged at levels exceeding
water quality standards/EPA criteria by this facility from outfall 002 (Ash
Pond). For the purposes of the RPA, the background concentrations for all
parameters were assumed to be below detection level. The RPA uses 95%
probability level and 95% confidence basis in accordance with the EPA
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Guidance entitled "Technical Support Document for Water Quality-based
Toxics Control."
RPA calculations included: As, Be, Cd, Chlorides, Cr, Cu, CN, Pb, Hg, Mo,
Ni, Se, Ag, Zn, Al, and B concentrations. The renewal application listed 1.0
MGD as the maximum flow. The analysis indicates no reasonable potential
to violate the surface water quality standards or EPA criteria.
RPA for Seeps (Outfalls 102, 108, 108B, and 110).
The RPA was also conducted for the combined flow from the seeps. The
analysis was based on the dilution in the receiving stream as a result of
delineation of the effluent channels for all seeps. Calculations included:
As, Cd, Chlorides, Cr, Cu, F, Pb, Hg, Mo, Ni, Se, Zn, Sulfate, Ba, Sb, and TI.
The analysis indicates no reasonable potential to violate the water quality
standards or EPA criteria. The flow volume for the combined seep flow
was measured at 0.006 MGD, this is approximately 0.03% of the ash basin
discharge. However, the flow of 0.5 MGD was used for the RPA to
incorporate a safety factor, account for potential new seeps that might
emerge in the future or increase in flow volume at the existing seeps.
In conclusion, the RPA analysis indicates that existing discharges from the
facility outfalls and seeps will not cause contravention of the state water
quality standards/ EPA criteria.
Other comments received during the first public period expressed issues that have
already been addressed above or are comments from specific organizations as listed
below.
The following is a summary of comments received from the Sierra Club:
• The Department proposes to permit the discharge of pollutants from illegal seeps
in violation of the Clean Water Act.
Response: The inclusion of the seeps into the NPDES permit is based on
the provisions of the Coal Ash Management Act of 2014 (CAMA). § 130A-
309.210 of the Coal Ash Management Act of 2014 requires owners of coal
combustion residuals surface impoundments to identify and assess all
discharges from the impoundments and to implement corrective action to
prevent unpermitted discharges from the impoundments to the surface
waters of the state. Identification of discharges includes engineered
channels designed or improved for the purpose of collecting water from
the toe of the impoundment (toe drains), as well as non-engineered seeps
and weeps. One method of proposed corrective action allowed under the
Act is to make application for a National Pollutant Discharge Elimination
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System (NPDES) permit amendment to bring the unpermitted discharge
under permit regulations. A Discharge Assessment Plan for the
unpermitted discharges at the Allen Steam Station was submitted by Duke
Energy to the Department on December 30, 2014. Under the permit, the
seeps would be monitored and subject to applicable effluent limits which
will ensure that seep discharges will not result in unacceptable impacts to
surface waters. Incorporation of the seeps into the NPDES permit is
considered an interim measure until the coal ash impoundments are
closed. The draft permit requires that the facility continue to implement a
plan for the identification of new seeps. A seep identification survey shall
be conducted semi-annually and new seeps are to be reported to the
Division within five days of detection. The DWR has been consulting with
EPA in regard to the incorporation of the seeps into the NPDES wastewater
permits.
• Seeps, leaks or other structural issues should be addressed directly with sound
engineering solutions, i.e., removal of all coal ash for reuse or stored in
adequately lined landfill.
Response: §130A-309.213 of the Act required the department to develop a
proposed classification system for all coal combustion residuals surface
impoundments, including active and retired sites. §130A-309.214 requires
owners of coal combustion residual surface impoundments to submit a
proposed closure plan for the Departments approval. High-risk
impoundments shall be closed no later than December 31, 2019,
intermediate-risk impoundments shall be closed no later than December
31, 2024, and low-risk impoundments shall be closed no later than
December 31, 2029.
• Limits that the Department has proposed are inadequate. Permits do not set any
limits on the discharge of cobalt, boron, strontium, zinc and a variety of harmful
pollutants. Proposed monitoring frequencies are inadequate.
Response: The sampling requirements in the draft NPDES permit are
based on the state and federal rules, regulations, and policies. The state
conducts a Reasonable Potential Analysis (RPA) to determine the need for
monitoring or a limit for a particular constituent. RPA is the statistical
analysis of the effluent data that was approved by EPA. The RPA is
conducted on the 126 parameters in the renewal/major modification
application. The RPA is conducted on the parameters that are above
detection level and have appropriate state water quality standard/EPA
criteria. The majority of the parameters in the renewal applications are
below detection level.
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• Draft permits should be revised to include numeric effluent limits that are based
on best available technology for all pollutants discharged into receiving
waterways.
Response: The sampling requirements in the draft NPDES permit is based
on the state and federal rules, regulations, and policies. The state conducts
a Reasonable Potential Analysis (RPA) to determine the need for a
monitoring or limit for a particular constituent. RPA is the statistical
analysis of the effluent data that was approved by EPA. The RPA is
conducted on the 126 parameters in the renewal/major modification
application. The RPA is conducted on the parameters that are above
detection level and have appropriate state water quality standard/EPA
criteria. The majority of the parameters in the renewal application are below
detection level. Effluent limits and monitoring for all pollutants of concern
is not necessary to ensure that the pollutants are adequately controlled
because many of the pollutants originate from similar sources, have similar
treatabilities, and are removed by similar mechanisms. Because of this, it
may be sufficient to establish effluent limits for one pollutant as a
surrogate or indicator pollutant that ensures the removal of other
pollutants of concern." The permit also implements Best Practicable
Technology Currently Available (BPT) as well as BAT requirements of 40
CFR 423 Steam Electric Power Generating Point Source Category.
The following is a summary of comments received from the Neuse Riverkeeper
Foundation:
• The pollution limits in the permits are too weak.
Response: The effluent limitations in the permit are established in
accordance with the existing federal and state rules and regulations. EPA
has recently updated 40 CFR 423 and after reviewing parameters of
concern established TBELs for several of these parameters. The EPA
decided that TBELs for all parameters of concern are not necessary
because "Effluent limits and monitoring for all pollutants of concern is not
necessary to ensure that the pollutants are adequately controlled because
many of the pollutants originate from similar sources, have similar
treatabilities, and are removed by similar mechanisms. Because of this, it
may be sufficient to establish effluent limits for one pollutant as a
surrogate or indicator pollutant that ensures the removal of other
pollutants of concern."
• Permitting the leaks violates the Clean Water Act.
Response: The inclusion of the seeps into the NPDES permit is based on
the provisions of the Coal Ash Management Act of 2014 (CAMA). § 130A-
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309.210 of the Coal Ash Management Act of 2014 requires owners of coal
combustion residuals surface impoundments to identify and assess all
discharges from the impoundments and to implement corrective action to
prevent unpermitted discharges from the impoundments to the surface
waters of the state. Identification of discharges includes engineered
channels designed or improved for the purpose of collecting water from
the toe of the impoundment (toe drains), as well as non-engineered seeps
and weeps. One method of proposed corrective action allowed under the
Act is to make application for a National Pollutant Discharge Elimination
System (NPDES) Permit amendment to bring the unpermitted discharge
under permit regulations. A Discharge Assessment Plan for the
unpermitted discharges at the Allen Steam Station was submitted by Duke
Energy to the Department on December 30, 2014. The facility identified 12
non-engineered and two toe drains from the ash settling basin. The two
toe drains and four of the non-engineered seeps were determined to
require coverage under the NPDES Permit. One seep did not need
coverage under the permit based on the low concentration of the
constituents associated with coal ash. Three of the seeps were determined
not to discharge to surface waters and one seep outfall pipe has been
grouted and no longer discharges. Sampling for three of the seeps was not
required in the permit because they could be underwater at higher lake
levels and that two other seeps would serve as representative sampling
locations for those three.
Incorporation of the seeps into the NPDES permit is considered an interim
measure until the coal ash impoundments are closed. The draft permit
requires that the facility continue to implement a plan for the identification
of new seeps. A seep identification survey shall be conducted semi-
annually and new seeps are to be reported to the Division within five days
of detection. The DWR has been consulting with EPA in regard to the
incorporation of the seeps into the NPDES wastewater permits.
The following is a summary of comments received from the Waterkeeper Alliance:
The draft permits for Allen and Marshall are patently illegal because they:
• Violate North Carolina's groundwater protection rules by allowing coal ash to
remain in leaking, unlined ponds that are causing violations of state groundwater
quality standards beyond regulatory compliance boundaries at Allen and
Marshall;
Response: According to 15A NCAC 02L .0106 (e), Any person
conducting or controlling an activity that is conducted under the
authority of a permit initially issued by the Department prior to
December 30, 1983 pursuant to G.S. 143-215.1 or G.S. 130A-294, and
Page 14 of 36

that results in an increase in concentration of a substance in excess
of the standards at or beyond the compliance boundary specified in
the permit, shall....(4) implement an approved corrective action plan
for restoration of groundwater quality at or beyond the compliance
boundary, in accordance with a schedule established by the
Secretary.
This rule indicates current permits that exceed 02L standards have actions
they must take while still being permitted. This rule does not indicate these
facilities cannot continue to be permitted; however,-it does require for the
facility to take corrective action. The Coal Ash facility at Allen Steam
Station is in this process. In addition, the Coal Ash Management Act
(CAMA) of 2013 directs each Coal Ash facility under 130A-309.211 to (a)
provide a groundwater assessment for any groundwater exceedances, and
(b) provide a corrective plan to address restoration of groundwater
quality. Closure plans must be submitted no later than December 31, 2019,
which must include ...provisions for completion of activities to restore
groundwater.. according to 02L requirements. Once classifications are
finalized, each impoundment, depending on their classification, will be
closed under options provided by 130A-309.214.
• Violate the Clean Water Act by failing to require Duke Energy to employ the best
available treatment technology to mitigate or eliminate its toxic wastewater
discharges, even though numerous other facilities with similar waste streams
(including several owned by Duke Energy and regulated by DENR) have
completely eliminated coal ash wastewater discharges;
Response: The draft NPDES permit requires both TBEL limits and BAT
limits in accordance with 40 CFR 423 Steam Electric Power Generating
Point Source Category.
• Violate the Clean Water Act by allowing the uncontrolled release of numerous
toxic pollutants into the Catawba River and its tributaries, decimating those
tributaries beyond recognition and subsequently contaminating the Catawba
River;
Response: § 130A-309.210 of the Coal Ash Management Act (CAMA) of
2014 requires owners of coal combustion residuals surface impoundments
to identify and assess all discharges from the impoundments and to
implement corrective action to prevent unpermitted discharges from the
impoundments to the surface waters of the state. Identification of
discharges includes engineered channels designed or improved for the
purpose of collecting water from the toe of the impoundment (toe drains),
as well as non-engineered seeps and weeps. One method of proposed
corrective action allowed under the Act is to make application for a
National Pollutant Discharge Elimination System (NPDES) permit
Page 15 of 36

amendment to bring the unpermitted discharge under permit regulations.
A Discharge Assessment Plan for the unpermitted discharges at the Allen
Steam Station was submitted by Duke Energy to the Department on
December 30, 2014. The facility identified 12 non-engineered and two toe
drains from the ash settling basin. The two toe drains and four of the non-
engineered seeps were determined to require coverage under the NPDES
Permit. One seep did not need coverage under the permit based on the
low concentration of the constituents associated with coal ash. Three of
the seeps were determined not to discharge to surface waters and one
seep outfall pipe has been grouted and no longer discharges. Sampling for
three of the seeps was not required in the permit because they could be
underwater at higher lake levels and that two other seeps would serve as
representative sampling locations for those three.
• Violate the Clean Water Act's public participation requirements by
preemptively authorizing currently undiscovered or nonexistent pollution
discharges, which will deprive the public of the opportunity to participate in future
enforcement and permitting proceedings as required under federal law; and
Response: § 130A-309.210 of the Coal Ash Management Act (CAMA) of
2014 requires owners of coal combustion residuals surface impoundments
to identify and assess all discharges from the impoundments and to
implement corrective action to prevent unpermitted discharges from the
impoundments to the surface waters of the state. Identification of
discharges includes engineered channels designed or improved for the
purpose of collecting water from the toe of the impoundment (toe drains),
as well as non-engineered seeps and weeps. One method of proposed
corrective action allowed under the Act is to make application for a
National Pollutant Discharge Elimination System (NPDES) permit
amendment to bring the unpermitted discharge
• Violate the Clean Water Act's anti-backsliding provisions by relaxing the terms of
the current wastewater permits for Allen and Marshall. Notably, the State of North
Carolina, including DENR, sued Duke Energy in 2013 for violating both the Allen
and Marshall permits. Now, rather than prosecuting those cases, DENR is simply
attempting to shirk its future enforcement obligations by changing the permits
rather than demanding compliance with them.
Response: Anti-backsliding provisions are applicable to the TBEL limits,
none of the TBEL limits in the proposed permit are less stringent than in
the existing permit.
• In addition to violating both the North Carolina law and the Clean Water Act, the
draft permits for Allen and Marshall demonstrate a lack of commitment to the
health and safety of North Carolina residents. These permits are a step in the
Page 16 of 36

wrong direction because they would allow Duke Energy to dump more toxic
water pollution into North Carolina's rivers than what is currently allowed.
Response: As stated above, none of the TBEL limits in the proposed
permit are less stringent than in the existing permit.
IV. November 4, 2016, Public Notice Comments Summary
A second public notice was published on the draft NPDES Permit modification on
November 4, 2016. The notice was published in the Gaston Gazette. Publication of the
notice was also posted on the DEQ website. The public comment period closed on
December 7, 2016.
The following comments were received from the Sierra Club:
A. DEQ's Proposed Compliance Deadlines for the Revised ELGs Are Not
Justified.
1. DEQ Should Require Allen to Comply with Effluent Limitations for FGD
Wastewater by November 1, 2018.
Response: The existing FGD system for the facility is unable to meet the
proposed As and Se limit with 100% consistency. Although, EPA used the
Allen data to develop ELG, it used 95/99% compliance scenario. Therefore,
Duke needs to optimize the performance of the existing system or install
the membrane ultrafiltration to meet the proposed FGD limits with 100%
compliance rate. Review of the FGD discharge data from 1/1/2011 through
8/2/2016 indicates that: a) the Se daily maximum limit would have been
violated 5 times out of 141 if it was implemented during the last permit
renewal; and b) the As daily maximum limit would have been violated 17
times out of 68 if it was implemented during the last permit renewal.
Hence, the data supports the argument that the existing system needs
additional treatment unit or at least optimization. Duke has reviewed the
potential installation schedule and will be able to install ultrafiltration
earlier than expected. Therefore, the permit will require the facility to meet
the FGD limits by May 1, 2020, if the company decided not to retire the
entire facility early. The decision regarding retirement will be made by June
30, 2017. The permit will also require the facility to operate the FGD
treatment system through the term of the permit.
2. DEQ Should Require Allen to Comply with a Zero Discharge Standard for
Bottom Ash Transport Water by November 1, 2018.
Page 17 of 36

i +
Response: The facility has to develop and install a dry handling system for
the bottom ash, Duke has provided the justification for the proposed
schedule. Therefore, the permit will establish the deadline for bottom ash
conversion as of December 31, 2023, (if the decision is made not to retire
the entire facility early).
B. DEQ Must Establish Technology-Based Effluent Limitations for the Discharge
of Ash Basin Legacy Wastewater.
Response: The EPA has recently conducted a comprehensive study of all
waste streams generated by the power plants, including legacy wastewater
and considered all potential pollutants of concern. Based on the results of
this study the EPA used all applicable rules and regulations and produced
an update to 40 CFR 423 on November 3, 2015. The EPA decided that
TBELs for all parameters of concern are not necessary because "Effluent
limits and monitoring for all pollutants of concern is not necessary to
ensure that the pollutants are adequately controlled because many of the
pollutants originate from similar sources, have similar treatabilities, and
are removed by similar mechanisms. Because of this, it may be sufficient
to establish effluent limits for one pollutant as a surrogate or indicator
pollutant that ensures the removal of other pollutants of concern."
Therefore, the effluent guidelines have been recently promulgated and
there is no need for BPJ decisions. This approach has been approved by
the EPA. In,addition, the final permit will contain physical-chemical
treatment requirement for decanting and dewatering to be consistent with
other Duke permits.
•
C. The Draft Permit Fails to Set Adequate Water Quality-Based Effluent
Limitations.
Response: The need for water quality based effluent permit limits is
determined according to a reasonable potential analysis (RPA). The RPA
procedure utilized by the Division is in accordance with EPA's regulation at
40 CFR 122.44(d)(1). The Fact Sheet explains that: "The Division
conducted EPA-recommended analyses to determine the reasonable
potential for toxicants to be discharged at levels exceeding water quality
standards/EPA criteria by this facility. For the purposes of the RPA, the
background concentrations for all parameters were assumed to be below
detections level. The RPA uses 95% probability level and 95% confidence
basis in accordance with the EPA Guidance entitled "Technical Support
Document for Water Quality-based Toxics Control." The RPA included
evaluation of dissolved metals' standards, utilizing a default hardness
value of 25 mg/L CaCO3 for hardness-dependent metals. The RPA
spreadsheets are attached to the Permit Fact Sheet.
Page 18 of 36

Permit limits are added only if the results of the RPA suggest potential for
exceeding the water quality standards, and are not arbitrarily assigned.
However, absence of permit limits does not allow the facility to violate
instream water quality standards.
The RPA procedure has been approved by EPA, to better understand the
assumptions used in the procedure it is necessary to study the EPA issued
"Technical Support Document for Water Quality-based Toxics Control." It
is a very thorough document of approximately 300 pages, it describes the
RPA procedure in a detailed manner. The RPA spreadsheet also have
sufficient information to demonstrate assumptions used for the procedure.
The comments incorrectly state that "reasonable potential for violating
water quality standards and criteria was found only for the decanting of
the ash pond". In fact, it was also found for dewatering of ash pond.
The Al, Co, V, B, Fe, and Mn were excluded from RPA because the state of
North Carolina does not have water quality standards for these
parameters. In addition, Fe and Mn have been recently removed from the
list of the state standards.
The citation of the 2L or IMAC standards to demonstrate the RPA
deficiency is inappropriate because these are groundwater standards and
RPA is designed to evaluate ability of the facility to meet the surface water
standards.
The assumption that the background concentration is zero is based on the
instream monitoring data, the monitoring data demonstrates that the
background concentration for the majority of the parameters of concern is
below detection level.
The WQBELs for decanting and dewatering are the same because they are
based on the water quality standards, if the facility discharges wastewater
at the level established by RPA it shall not contravene the water quality
standards in the receiving stream. The original concentration of the
pollutants in the wastewater is not relevant in this consideration.
D. DEQ's Proposed Regulation of the Ash Basin Seeps Circumvents Clean
Water Act Requirements.
Response: § 130A-309.210 of the Coal Ash Management Act (CAMA) of
2014 requires owners of coal combustion residuals surface impoundments
to identify and assess all discharges from the impoundments and to
implement corrective action to prevent unpermitted discharges from the
impoundments to the surface waters of the state. Identification of
discharges includes engineered channels designed or improved for the
Page 19 of 36

purpose of collecting water from the toe of the impoundment (toe drains),
as well as non-engineered seeps and weeps. One method of proposed
corrective action allowed under the Act is to make application for a
National Pollutant Discharge Elimination System (NPDES) permit
amendment to bring the unpermitted discharge under permit regulations.
This approach was approved by the EPA.
E. The Draft Permit Sets Inadequate Monitoring Requirements.
Response: Frequency of monitoring and number of parameters that are
being monitored are based on the results of the reasonable potential
analysis (RPA) and requirements contained in Federal and State rules and
regulations. If a parameter shows reasonable potential and requires a limit,
monitoring is generally at a monthly or quarterly frequency. If a parameter
does not show reasonable potential, monitoring might not be required.
Monthly discharge monitoring reports (DMRs) and priority pollutant scans
(required with each permit renewal) are evaluated for RPA with each
renewal. The proposed monitoring frequencies will provide adequate
information to conduct RPA for the next permit renewal. The Division has a
long term monitoring data for coal-fired facilities' discharges and
accumulated a statistically significant dataset for all typical pollutants
associated with the coal ash. This data set allows for an accurate
characterization of the discharge from ash ponds at the frequency
prescribed in the permit. In addition, Duke submitted chemical
characterization of the wastewater in ash lagoons that demonstrates little
variation in the pollutant concentration at the different depth levels.
Therefore, additional monitoring is not likely to provide any additional
useful information. The EPA has approved the proposed monitoring
frequency.
F. Contamination from the Unlined Ash Basin Threatens Ground and Surface
Waters and Requires Immediate Corrective Action.
1. Toxic Contaminants from Allen's Unlined Coal Ash Basins Are Violating
Groundwater Protection Standards and Threatening Ground and Surface Waters.
Response: DEQ filed four lawsuits in 2013 in order to direct Duke Energy
to address "alleged" violations of groundwater and surface water. In 2014,
the Coal Ash Management Act (CAMA) followed this up when it directed
each Coal Ash facility (including Allen Steam Station) under 130A-309.211
to (a) provide a Comprehensive Site Assessment and Corrective Action
Plan that addresses groundwater exceedances, as well as any impacts to
receptors of the contaminated groundwater (i.e. surface water).
In the past two years, Duke Energy has submitted both of these reports and
has submitted Interim Monitoring Plans that address their continued
sampling and analysis of both groundwater and surface water. As of to
Page 20 of 36

date, a Corrective Action Plan has not approved and data continues to be
submitted for DEQ's evaluation.
2. The Unlined Ash Basin Is Polluting the Catawba River Through Hydrologically
Connected Groundwater.
Response: The NPDES program regulates point source discharges to the
Waters of the US, the infiltration of the wastewater to the groundwater does
not fit the definition of the point source discharge. The groundwater
contamination is being regulated under a separate program within DWR.
The comprehensive impact of the facility is being assessed by instream
monitoring.
The facility has been conducting the long-term monitoring of the Catawba
river in connection with the 316a variance. Recent monitoring results
demonstrated that the majority of the results for sampled parameters
above and below the discharge are below detection level (Hg, As, Cd, Cr,
Pb, Se), the rest of the results are below water quality standards (Cu, Zn,
TDS). No parameter demonstrated any increase in the concentration at the
monitoring stations below the discharge.
3. Immediate Corrective Action is Required to Meet Federal Groundwater
Requirements at the Unlined Ash Basin.
Response: According to 15A NCAC 02L .0106 (e), Any person conducting
or controlling an activity that is conducted under the authority of a permit
initially issued by the Department prior to December 30, 1983 pursuant to
G.S. 143-215.1 or G.S. 130A-294, and that results in an increase in
concentration of a substance in excess of the standards at or beyond the
compliance boundary specified in the permit, shall....(4) implement an
approved corrective action plan for restoration of groundwater quality at or
beyond the compliance boundary, in accordance with a schedule
established by the Secretary.
This rule indicates current permits that exceed 02L standards have actions
they must take while still being permitted. This rule does not indicate these
facilities need additional permit conditions or cannot continue to be
permitted; however, it does require for the facility to take corrective action
"...for the restoration of groundwater quality at or beyond the compliance
boundary..." The Coal Ash facility at Allen Steam Station is in this
process. In addition, the Coal Ash Management Act (CAMA) of 2014 directs
each Coal Ash facility under 130A-309.211 to (a) provide a groundwater
assessment for any groundwater exceedances, and (b) provide a corrective
plan to address restoration of groundwater quality. And finally, closure
plans must be submitted no later than December 31, 2019, which must
include ...provisions for completion of activities to restore groundwater...
Page 21 of 36

according to 02L requirements. Once classifications are finalized, each
impoundment, depending on their classification, will be closed under
options provided by 130A-309.214.
G. Duke Energy's 316(a) Assessment Does Not Justify a Variance from North
Carolina's Water Quality Standard for Temperature.
I. Duke's BIP Assessment Is Based on a Faulty and Impaired Reference Area.
Response: Water Sciences Section staff that originally reviewed the 2014
report continue to stand by the report's conclusions.
The issue regarding the reference area is correct and valid. A new
reference area on Lake Wylie upstream from the discharge should be
identified or, if that is not possible, then a suitable region of a nearby
reservoir (e.g., Mountain Island or Lake Norman) should be chosen as the
reference area.
II. Duke's BIP Assessment Does Not Justify a Thermal Variance for Allen.
Response: Water Sciences Section staff that originally reviewed the 2014
report continue to stand by the report's conclusions.
Water Sciences Section staff recognize that the study design and report did
not conform to the EPA's 1977 draft §316(a) Guidance Manual which Duke
Energy was requested to follow as specified in the 2011 NPDES
permit. Specifically:
a. Duke Energy did not spatially and temporally diagram and quantify the
thermal plume; and
b. Duke Energy did not provide a list and survey of endangered or
threatened species in the reservoir or with the vicinity of the Allen
Steam Station.
Issues raised regarding impacts to the Carolina Heelsplitter (a mussel) and
the Atlantic Highfin Carpsucker (a fish) are not valid. The Carolina
Heelsplitter would not be found in a reservoir environment with or without
a power plant discharging heated effluent into the reservoir and the
Atlantic Highfin Carpsucker is likely extirpated from North Carolina.
III. Allen's Thermal Discharges Have Caused Harmful Impacts, and Such
Impacts Likely Will Be Exacerbated by the Effects of Climate Change.
Response: Water Sciences Section staff that originally reviewed the 2014
report continue to stand by the report's conclusions.
Water Sciences Section staff do not have the expertise in thermal
mathematical modeling to comment upon any issues related to global or
regional climate change.
Page 22 of 36

H. DEQ Fails to Establish or Consider Interim.Requirements to Reduce
Impingement and Entrainment in the Draft Permit.
Response: The DEQ has agreed with the justification provided by Duke
Energy to provide an alternative schedule under 316(b). The alternative
schedule is allowed by the 316(b) rule and has been approved by EPA.
In addition, it would require a substantial time and effort to develop these
rules. EPA has a dedicated Division to develop such rules and it took EPA
7 years to develop 316b rule (from 2007 to 2014) and 6 years to develop the
update to 40 CFR 423 (from 2009 to 2015). The DWR does not have
sufficient resources to develop the interim measures under a very severe
time constrains. The facility has to meet deadlines in CCR and CAMA, and
without the permit the facility will not be able to meet these deadlines. The
expedited closure of ash ponds would be more beneficial to the
environment than many years spent on the development of interim
measures, which would delay the closure.
The following comments were received from Duke Energy:
• Per 15A NCAC 02B.0206(b), in cases where the stream flow is
regulated,a minimum daily bw flow may be used as a substitute for the
7Q10flow.The Federal Energy Regulatory Commission(FERC)license for
the Catawba-Wateree Hydroelectric Project No. 2232 issued Nov. 25,
2015 establishes a minimum average daily release requirement from
Wylie Hydro of 411 cfs.Therefore, the reasonable potential analysis
should be conducted at a 7Q10S of 411cfs.
Response: The Division used the historic minimum release number for the
RPA. If the new number is used, the permit would have to be re-noticed and
the comment period will be reopened. This will significantly delay the
issuance of the final permit and Duke Energy indicated the urgent need for
a new permit.
• Regarcfng the total silver limit in sections A. (2.) and A. (3.),we do not believe
this limit is appropriate due to the history of analytical results and due to the
minimum release requirement discussed in #1 above. Based on quarterly
monitoring Sliver has not been detected above the detection imit in the
previous four years. Duke requests that the limit for total silver be removed
and that monitoring and reporting for total silver be conducted for a year,and
if silver is not detected, Duke requests that the monitoring and reporting
requirement be removed.
•
Page 23 of 36

A
Response: The limit for silver has been implemented in accordance with
the existing federal and state rules and regulations. The Division is unable
to remove this limit.
• In section A. (2.),the monitoring frequency for selenium, arsenic,
silver, and mercury is"weekly," in contrast to the "monthly" or
"quarterly" monitoring frequency in the current permit. Historical
monitoring data do not indicate any issues concerning the discharge
from outfall 002, especially the aforementioned parameters. The RPA ,
demonstrates the discharge will not cause contravention of the water
quality criteria for any ofthese parameters.Given that morefrequent
monitoring isnot necessary to address an immediate concern and
considering comments #1 and#2 above, Duke requests the sampling
frequency be changed to"quarterly". If morefrequent monitoring is
required, Duke would not object to"monthly"sampling.
Response: Selenium, Arsenic, Silver, and Mercury are the parameters of
concern. The previous experience with the decanting indicates that these
pollutants might cause contravention of the water quality standards in the
receiving stream and the Division needs to closely monitor these
parameters to assure protection of the environment.
•' For outfall 006, the chronic toxicity is to be tested at an instream waste
concentration (IWC) of 23.6%: the same as the current ash basin. The
23.6% is reputedly based on the effluent flow and 7Q10S of the receiving
water. The effluent flow from the retention basin has a maximum design
of 3.3 MGD which is significantly less than the effluent flow (18.9 MGD)
from the current ash basin and should reduce the concentration at which
Duke should be required to conduct the chronic toxicity testing.
Additionally, as mentioned in comment #1,the FERC license establishes a
minimum average daily release requirement from Wylie Hydro of 411 cfs.
Duke requests that the WC be reviewed and adjusted based on the
expected outfall 006 discharge flow and FERC minimum release.
Response: Since the new retention basin will accept all the wastes that are
currently discharged to the ash basin, it is reasonable to suggest that the
IWC is the same for both treatment units. The Division is willing to change
this number if Duke accepts the flow limit, it also can be changed based on
the actual flow data during the next permit renewal.
• Concerning sections A. (2.) and A. (3.), Duke requests that BOD and
fecal coliform limits be removed from the permit. The limitation of fecal
coliforms in an open pond impoundment is of questionable merit, when
such impoundment is an attractive and active habitat area for wildlife and
more specifically a nesting area for a variety of species of water fowl.
Page 24 of 36

Response: The Division unable to grant this request since the ash pond
is used for discharge of domestic wastewater, which has applicable
TBELs. In addition, this requirement was imposed by the EPA.
• Duke requests the removal of internal outfall 009. The holding basin
was designed as a "pre treatment" step, which allows some initial solids
removal and pH adjustment treatment in the retention basin. This
design allows an effective retention basin that has been constrained
in its size by the available space on the property. The rationale in
creating this internal outfall is unclear. Nevertheless, the internal outfall is
not necessary, and Duke requests that it be removed.
Response: The Division has established the internal outfall 009 to comply
with the requirements of 40 CFR 423 for the low volume wastes and the
coal pile runoff.
• Duke requests the removal of internal outfall 007. At one point in the
development of the new retention basin project, it was believed there was
a need to have two functional internal outfalls at the same time. The
design has progressed to the point where only one internal outfall will be
necessary. Duke would like to keep internal outfall 005 as the only internal
outfall.
Response: The Division is unable to substantial change the permit at this
stage without re-opening the permit. In addition, we have experienced
numerous changes in the design process for Duke permits and it would be
prudent to keep this option open until the next renewal
• In section A. (8) Duke requests the removal of the TSS, oil and grease,
and pH limits for the FGD internal outfall. The limits for TSS, oil and
grease, and pH are based on the best practicable control technology
currently available for FGD wastewater. Since the pH limits apply to all
waste streams and the TSS and O&G limits are the same as low volume
waste streams, these limits should not apply to the internal outfall but
rather to the final outfall to allow for co-treatment.
Response: These requirements are implemented in accordance with 40
CFR 423. The Division is unable to grant this request.
• As stated in the Fact Sheet,the facility has passed all toxicity testing
during the previous permit cycle (20 out of 20). h section A. (2.),A. (3.),
and A. (10.),the measurement frequency for chronic toxicity is monthly;
however, section A. (20.)explicitly states that the samples are to be
taken in January,.April, July, and October,which isthe current
requirement. Duke requests that the measurement frequency for chronic
toxicity be changed to"Quarterly"throughout the text of the permit.
Page 25 of 36

Response: The proposed monitoring frequency is consistent with other
Duke permits and is based on the need to decant and dewater ash ponds,
which require more frequent monitoring due to the potentially higher
pollutant concentrations.
• The car wash that contributed vehicle washwater to outfall 004 has been
removed. Duke requests that the oil and grease limits in section A. (7.) be
removed.
Response: The Division is unable to remove this limit without re-opening
the permit. This change will be done during the next permit renewal.
• In section A. (4.) please amend the text to read that Duke should notify
the DWR Mooresville regional office instead of"DWR Winston-Salem
Regional".
Response: The correction will be made in the final permit.
• In sections A. (4.) and A. (5.), please reinsert the following language that is
h the facility's current permit:
"Sampling is required per occurrence when sump overflows occur for bnger
than one hour. Monthly average limits only apply if the overflow occurs for more
than 24 hours".
Response: The Division is unable to grant this request. This change
has been made to address the EPA comment.
• In footnote 4 of sections A. (8.), please specify that only monitoring and
reporting is required until the applicable date that depends on the retirement
decision.
Response: The change will be made in the final permit.
• In section A. (2.), Duke requests that the language in footnotes 7 and 8 be
clarified to state that continuous monitoring of total suspended solids and pH
is only required when decanting via pumps and that the continuous
monitoring requirements and limitations be restricted to in-process samples.
This language should likewise be reflected in footnotes 6 and 8 ofsectionA.
(3.). As this language was developed priorto additional requirements to
provide physicaVchemical treatment, this requirement is unnecessary
because any water removed via pump wilt be treated priorto release.
Response: The Division will make a clarification regarding the pump
operation. However, the other changes cannot be made. These
measurements have been implemented to address the EPA comments
and consistent with other Duke permits. All the measurements shall be
Page 26 of 36

� t
conducted after the final treatment unit and prior to the discharge to
the receiving stream.
• In section A. (2.), instead of "The fruits.and conditions ... below the
three feet trigger mark", Duke Energy requests that the following
language be substituted: "During decanting the facility is allowed to
drawdown the wastewater h the ash basin to no less than three feet
above the ash at the pump intake bcation. Lowering the level below
the three feet mark triggers the limits and conditions in section A.(3.)
of this permit. This provides clarity regarding what the "three feet
trigger' is and what limits apply.
Response: The Division will make the clarification in the final permit.
• h sections A. (2.)and A. (3.)the "ash pond/ponds decommissioning
process" is not well defined. Duke understands that itwill be allowed
to determine when its decommissioning process has started and
subsequently when it is necessary to deploy physical-chemical
treatment facilities.
Response: The Division concurs with this interpretation of the permit.
• Wastewater from chemical metal cleaning is no bnger discharged.
Duke requests that limitations associated with chemical metal cleaning
be removed from the permit.
Response: The Division is unable to grant this request. Such change
would require the reopening of the permit. The limits in the permit are
applicable to the discharges of the chemical metal cleaning only and if
these wastes are not discharging the facility does not need to meet
these limits.
• In section A.(28.) it is unclear why bromide, hardness, and turbidity
were added as parameters for instream monitoring. Please remove
these parameters from the instream monitoring until the justification
can be evaluated and commented on.
Response: Monitoring for hardness is required to calculate the
appropriate limits in the permit. Monitoring for turbidity is required to
determine compliance with the turbidity standard. Monitoring for
bromide is required to determine potential negative impacts on the
drinking water treatment plants.
• In section A. (28.) it is unclear whether the nstream monitoring and
analysis for metals is total or dissolved. Duke understands that
dissolved metals are what were likely ntended. Please clarify if
Page 27 of 36

a A
dissolved metals monitoring and analysis is the requirement for
instream monitoring.
Response: The Division will make a clarification in the final permit.
• Section A. (28.)states "In-stream monitoring should be conducted at the
stations that have already been established through the BIP monitoring
program".The same section also mentions Station 250 and Station 235.
Please clarify if the intent is to monitor at Station 250 and Station 235 or if
Duke will have the flexibility to choose bcations within its BIP monitoring
program. The BIP stations were established to monitor thermal impacts.
Station 235 is downstream of the confluence of the South Fork Catawba
River, and readings at that point may be influenced by that water body.A
bcation closer to the ash basin dscharge on the Catawba River main stem
may be more appropriate to characterize any potential trace metal
influences from the ash basin discharge.
Response: The intent of the permit is to monitor at the Station 250 and
at the Station 235. These stations have a long term monitoring data that
can be used as a base-line to determine any impacts from the
decommissioning of the ash ponds.
In section A. (2.), the permit imposes a daily maximum Emit of 50 mg/L
for total suspended solids based on 40 C.F.R.123. The ash basins
designed, constructed, and operated to treat the volume of coal pile
runoff associated with at least a 10 year, 24 hour rainfall event;
therefore, the 50 mg/L maximum does not apply per 40 C.F.R.
§423.12(b)(10). The daily maximum TSS limit should be revised to 100
mg/L.
Response: The TSS limit is imposed in accordance with 40 CFR 423.
• Limits for turbidity are proposed for outfall 002, which also has proposed
limits for total suspended solids (TSS). TSS is a parameter that is sufficient
to show that the wastewater treatment system is properly operating. The
potential exists for significant interferences in the analysis for turbidity.
For example, air bubbles and/or light absorbing materials can significantly
interfere with the readings. Turbidity 's also not a direct measurement of
the total suspended materials in water. Turbidity is instead a measure of
relative clarity, and is often used to indicate changes n the total suspended
solids concentration in water without providing an exact measurement of
solids. Duke requests that since these outfalls are limited by TSS that
the limitations and monitoring of turbidity be removed.
Response: The turbidity limit is imposed to assure the compliance with
the state turbidity standard.
Page 28 of 36 •

.
• For those parameters without explicit limitations, Duke understands
that the requirement is to "monitor and report" unless the
measurement frequency is given as"waived". For those parameters
where the measurement frequency is"waived", no monitoring or
reporting is necessary.
Response: The Division concurs with this interpretation of the permit.
• Section A. (27.)says that fish tissue monitoring will be in accordance with a
"sampling plan approved by the Division", however, the permit does not
give specific provisions for how the plan is submitted or approved. Duke
will submit requests for plan approval to the Division's environmental
sciences group within 180 days of permit approval.
Response: The Division concurs with this interpretation of the permit. •
• In section A. (30.)the text should reflect that there are 11 seeps; five of
which do not need coverage under the permit. The text should also be
corrected to read as "Each outfall discharges through its own effluent
channel meeting the requirements in 15A NCAC 2B .0228".
Response: The number of seeps is based on the documents submitted
by Duke. All the seeps and the explanation for their inclusion in the
permit or exclusion from the permit can be found in the Fact Sheet.
• Table 1 in section A. (30.)should be corrected as follows:
Discharge ID Latitude Longitude Outfall
Number
S-2 35°10.426'N 81°0.347'W 102
5-3 (toe drain) 35°10.512'N 81°0.360'W 103
S-4 (toe drain) 35°10.541'N 81°0.364'W 104
S-8 35°10.710'N 81°0.384'W 108
S-8B 35°10.689'N 81°0.391'W 108B
S-10 35°10.884'N 81°0.367'W 110
Response: The Division will make a correction in the final permit.
• In section A. (30.) under"Discharges from Seepage Identified After Permit
Issuance", Duke requests that it be given 180 days after dscovery of a
new seep to determine if the discharge meets state water quality
standards and submit the results to DWR. Duke also understands that the
determination as to whether water quality standards have been met is
Page 29 of 36

outlined in condition A. (28.) of the permit
Response: The Division is unable to grant this request. This condition
has been established in accordance with EPA requirements and is
consistent with other Duke permits.
• In section A. (30.) Duke requests the removal of"The Effluent
Channel"'designation should be established by the DEQ Regional
Office personnel prior to the issuance of the permit".
Response: The Division is unable to grant this request. This
requirement is established in accordance with 15A NCAC 2B .0228.
The following comments were received from the Southern Environmental Law Center
1) DEQ's Proposed Approach for Permitting Seepage from the Ash Basins
Violates the Clean Water Act.
A. Permitting Waters of the United States as "Effluent Channels"Violates the
Clean Water Act and North Carolina Law.
Response: The Effluent Channels at the Allen Steam Station have been
delineated in accordance with the requirements of 15A NCAC 02B .0228.
The EPA and USACOE did not object to this action.
B. The CWA Prohibits Ignoring Point Source Discharges.
Response: The seep S-1 was excluded from the permits for the following
reasons: the concentrations of B, Se, and As in this seep are below
detection level. Therefore, this seep does not discharge wastewater and
don't need to be covered by the permit. Seeps S-8C, S-11 and S-12 do not
discharge to the "Waters of the State", and thus don't need the coverage.
Seeps S-5, S-6, and S-7 present safety concern and have an extremely low
flow of less than 1GPM, they also may be under water during wet periods.
Hence, they were excluded from coverage. It is also important to
emphasize that the flow volume for the combined seep flow is measured at
0.006 MGD, this is approximately 0.03% of the ash basin discharge.
C. The Draft Permit Sets Inadequate Monitoring Requirements for Seeps
and Does Not Assure Permit Modifications for New Seeps Will Comply with
Public Notice Requirements.
Response,: Frequency of monitoring and number of parameters that are
being monitored are based on results of the reasonable potential analysis
(RPA) and requirements contained in the Federal and State rules and
regulations. If a parameter shows reasonable potential and requires a limit,
Page 30 of 36

monitoring is generally at a monthly or quarterly frequency. If a parameter
does not show reasonable potential, monitoring might not be required.
Monthly discharge monitoring reports (DMRs) and priority pollutant scans
(required with each permit renewal) are evaluated for RPA with each
renewal. The proposed monitoring frequencies will provide adequate
information to conduct RPA for the next permit renewal. The permit also
clearly requires re-opening and the Public Notice for the new seeps.
2) The Draft Permit Fails to Account for Discharges of Wastewater Through
Hydrologically Connected Groundwater.
Response: The NPDES program regulates point source discharges to the
Waters of the US, the infiltration of the wastewater to the groundwater does
not fit the definition of the point source discharge. The groundwater
contamination is being regulated under a separate program within DWR.
The comprehensive impact of the facility is being assessed by instream
monitoring.
3) The Department Cannot Issue a Permit to a Facility that is Violating
Surface Water Standards
Response: There is no evidence that the discharge from facility violates
water quality standards in the receiving stream. The citation used in the
comment addresses the permits that cannot assure compliance with the
water quality standards. However, the proposed permit was based on the
existing federal and state rules and regulations and will provide
compliance with the water quality standards in the receiving water bodies.
The statement used by SELC as an evidence of standard violations simply
indicates that the stream is impacted, but it does not indicate the violation
of the water quality standards.
4) The Draft Permit Violates Requirements Applicable to Surface Waters
Classified as Water Supply Areas.
Response: The SELC provided no evidence that surface water quality
standards have been violated. The instream monitoring data demonstrates
compliance with water quality standards. The permit already requires semi-
annual upstream and downstream monitoring near the ash pond discharge.
The upstream site (Station 250) is approximately 1.1 miles upstream of the
discharge and downstream location (Station 235) is approximately 3 miles
downstream of the discharge. These monitoring stations have been
established through the BIP monitoring program, which was required to
maintain the 316(a) temperature variance. The monitored parameters are:
As, Cd, Cr, Cu, Hg, Pb, Se, Zn, turbidity, and Total Dissolved Solids (TDS).
The majority of the results are below detection level (Hg, As, Cd, Cr, Pb,
Se), the rest of the results are below water quality standards (Cu, Zn, TDS).
Page 31 of 36

k -
No parameter demonstrated any increase in the concentration at the
monitoring stations below the discharge.
5) The Reasonable Potential Analysis is Inadequate.
Response: The RPA used for the development of the permit is a statistical
means of evaluating whether toxicants discharged by a facility have a
reasonable potential to cause an exceedance of water quality standards or
EPA-recommended criteria in the receiving stream. The Division's
methodology is approved by the U.S. EPA and is consistent with the EPA's
Technical Support Document for Water Quality-based Toxics Control, or
"TSD".
The RPA evaluates actual effluent data for each waste discharge and
estimates the maximum concentration for each pollutant of concern that
will not be exceeded in 95% of future samples, with 95% confidence. It also
calculates for each parameter the maximum allowable effluent
concentration, which is the highest discharge concentration that, at design
discharge flow and statistical low flows in the receiving stream, will not
exceed the surface water quality standard or criterion in the stream. If the
maximum predicted effluent concentration of a pollutant is greater than the
maximum allowable concentration, the discharge is said to show a
reasonable potential to cause an exceedance of that standard or criterion.
When that is the case, an effluent limit is warranted and is included in the
permit.
6) The Permit Fails to Impose Sufficiently Stringent Technology Based
Effluent Limitations.
A. Effluent Limitations Must be Added to the Draft Permit.
Response: The EPA has recently conducted a comprehensive study of
all waste streams generated by the power plants and considered all
potential pollutants of concern. Based on the results of this study the
EPA used all applicable rules and regulations and produced an update
to 40 CFR 423 in 2015. The EPA decided that TBELs for all parameters of
concern are not necessary because "Effluent limits and monitoring for
all pollutants of concern is not necessary to ensure that the pollutants
are adequately controlled because many of the pollutants originate from
similar sources, have similar treatabilities, and are removed by similar
mechanisms. Because of this, it may be sufficient to establish effluent
limits for one pollutant as a surrogate or indicator pollutant that ensures
the removal of other pollutants of concern." Therefore, the effluent
guidelines have been recently promulgated in there is no need for BPJ
decisions.
Page 32 of 36

B. The Department Has Not Justified Extended Deadlines for Compliance
with New Effluent Limitations.
Response: The existing FGD system for the facility is unable to meet
the proposed As and Se limit with 100% consistency. Although, EPA
used the Allen data to develop ELG, it used 95/99% compliance
scenario. Therefore, Duke needs to optimize the performance of the
existing system or install the membrane ultrafiltration to meet the
proposed FGD limits with 100% compliance. Review of the FGD
discharge data from 1/1/2011 through 8/2/2016 indicates that:
a) Se daily maximum limit would have been violated 5 times out
of 141 if it was implemented during the last renewal
b) As daily maximum limit would have been violated 17 times out
of 68 if it was implemented during the last renewal.
Hence, the data supports the argument that the existing system needs
additional treatment unit or at least optimization. Duke has reviewed the
potential installation schedule and will be able to install ultrafiltration
earlier than expected. Therefore, the permit will require the facility to meet
the FGD limits by May 1, 2020, if the company decided not to retire the
entire facility early. The decision regarding retirement will be made by June
30, 2017. The permit will also require the facility to operate the FGD
treatment system through the term of the permit.
Response regarding the bottom ash: The facility has to develop and install
a dry handling system for the bottom ash, Duke has provided the
justification for the proposed schedule. Therefore, the permit will establish
the deadline for bottom ash conversion as December 31, 2023 (if the
decision is made not to retire the entire facility early).
7) The Proposed Permit Violates North Carolina's Groundwater Rules
DEQ Must Impose Conditions to Prevent Further Groundwater
Contamination
Response: According to 15A NCAC 02L .0106 (e), Any person
conducting or controlling an activity that is conducted under the
authority of a permit initially issued by the Department prior to
December 30, 1983 pursuant to G.S. 143-215.1 or G.S. 130A-294, and
that results in an increase in concentration of a substance in excess
of the standards at or beyond the compliance boundary specified in
the permit, shall....(4) implement an approved corrective action plan
for restoration of groundwater quality at or beyond the compliance
boundary, in accordance with a schedule established by the
Secretary.
Page33of36

This rule indicates current permits that exceed 02L standards have actions
they must take while still being permitted. This rule does not.indicate these
facilities cannot continue to be permitted; however, it does require for the
facility to take corrective action. The Coal Ash facility at Allen Steam
Station is in this process. In addition, the Coal Ash Management Act
(CAMA) of 2013 directs each Coal Ash facility under 130A-309.211 to (a)
provide a groundwater assessment for any groundwater exceedances, and
(b) provide a corrective plan to address restoration of groundwater
quality. Closure plans must be submitted no later than December 31, 2019,
which must include ...provisions for completion of activities to restore
groundwater... according to 02L requirements. Once classifications are
finalized, each impoundment, depending on their classification, will be
closed under options provided by 130A-309.214.
1 DEQ Must Define Compliance and Review Boundaries and Require
Groundwater Monitoring Pursuant to the Groundwater Rule.
Response: According to 15A NCAC 02L .0107, individually permitted
sites have a compliance boundary established at a set horizontal
distance from the waste boundary (or the property boundary,
whichever is closest to the source), the distance depending whether
the permit was permitted prior to December 30, 1983 or after
December 30, 1983. Thus the Compliance Boundary is established by
rule.
As for groundwater monitoring, Duke Energy continues to do extensive
groundwater monitoring. Duke Energy not only monitors its compliance
wells under its NPDES permit, it also monitors groundwater wells, both
inside and outside of the compliance boundary, described in the Final CSA
Supplement 2 Allen Report. According to the Final CSA Supplement 2
Allen Report, additional groundwater monitoring wells and soil borings
were installed. The Final CSA Supplement 2 Allen Report can be found at:
http://edocs.deq.nc.govlWaterResou rces/Browse.aspx?startid=221202&d bi
d=0. : Under this same link, in the folder for Interim Sampling Plans, a DEQ
letter Facility Interim Monitoring Plans Networks and Sampling
Requirements, dated December 21, 2016, gives further direction to Duke
Energy for sampling and reporting requirements. The first attachment
specifically addresses Allen Steam Station requirements.
8) DEQ Cannot Re-issue a Permit with Ongoing Violations of the Removed
Substances Provision.
Response: The disposal of the coal ash in wet lagoons has been authorized
by the EPA in accordance with the CWA. The lagoons are designed to
Page 34 of 36

remove the solid ash only. New federal regulations will gradually phase out
the use of coal ash lagoons. The permit does not allow the discharge of
coal ash from any of the outfalls, including seeps.
9) Duke Energy's 316(a) Demonstration is Inadequate to Justify a Variance
from North Carolina's Water Quality Standard for Temperature. _
Response: Water Sciences Section staff that originally reviewed the 2014
report continue to stand by the report's conclusions.
The issue regarding the reference area is correct and valid. A new
reference area on Lake Wylie upstream from the discharge should be
identified or, if that is not possible, then a suitable region of a nearby
reservoir (e.g., Mountain Island or Lake Norman) should be chosen as the
reference area.
V. Recommendations
Based on the review of the public record, written and oral public comments, the
North Carolina General Statutes and Administrative Code, the Coal Ash
Management Act of 2014, the site visit and discussions with other DWR staff, I
recommend to the Division Director that the draft NPDES permit for the Marshall
Steam Station be modified and issued with the following changes:
1. The Division should consider adjusting the IWC for Outfall 006 chronic
toxicity testing based on a maximum design flow from the proposed new
retention basin of 3.3 MGD. If the IWC is adjusted, the effluent limits page
for Outfall 006 should be modified to include a daily maximum flow limit.
2. Section A. (4.) of the draft permit should be amended to correct that Duke
should notify the DWR Mooresville Regional Office.
3. Clarifying language should be added to Footnote 4 of Section A. (8.) to
specify that only monitoring and reporting is required until the applicable date
based on the retirement decision of the coal fired units.
4. Clarifying language should be added to Footnotes 7 and 8 of Section A. (2.)
and Footnotes 6 and 8 of Section A. (3.) to specify that continuous
monitoring of TSS and pH is only required when decanting via pumps.
5. Clarifying language should be added to Section A. (2.) to specify that during
decanting the facility is allowed to drawdown the wastewater in the ash basin
to no less than three feet above the ash level at the pump intake location and
that lowering the level below the three feet mark triggers the limits and
conditions in Section A. (3.) of the permit.
Page 35 of 36

E:�
6. Clarifying language should be added to Sections A. (2.) and A. (3.) to specify
that Duke will determine when the decommissioning process of the coal fired
units has started and when it is necessary to deploy physical-chemical
treatment facilities.
7. Clarifying language should be added to Section A. (28.) to specify instream
monitoring for dissolved metals.
8. Table 1 in Section A. (30.) should be corrected to add "N" and "W" to latitude
and longitude coordinates, respectively.
VI. Attachments
A. NPDES Applications
B. Draft Permits and Fact Sheets
C. Written comments received during public comment period
D. Public Hearing transcript, including oral comments
E. Notice of Public Hearing
F. Speaker sign-in sheets
G. Non-speaker sign-in sheets
•
Page 36 of 36