Allen Steam Facility - Duke Energy (23)

a
NCDENR
North Carolina Department of Environment and Natural Resources
Division of Water Quality
Beverly Eaves Perdue Coleen H. Sullins Dee Freeman
Governor Director Secretary
STAFF REVIEW AND EVALUATION
NPDES Stormwater Permit
Facility Name:
Duke Energy Carolinas, LLC - Allen Steam Station
DIVISION OF WATE
Q
NPDES Permit Number:
NCS000546
MAY 13 2011
8
Facility Location:
253 Plant Allen Road, Belmont, NC (Gaston County)
, . _ ,t
MOORESViLL
4` Lam' �"
t< REGION
Type of Activity:
Steam Electric Generation
L
SIC Code (if applicable):
4911
Receiving Streams:
See Figure 1
River Basin:
Catawba River Basin, Sub -basin 03-08-37
Stream Classification:
WS -V, B
Proposed Permit Requirements:
See attached draft permit.
Monitoring Data:
See Table 1
Response Requested by (Date):
June 8, 2011
Central Office Staff Contact:
Return to: Bethany Georgoulias, [phone]
Special Issues:
Compliance history
5
Benchmark exceedance
5
Location (TMDL, T&E
species, etc
3
Other Challenges:
• Power Plant -
New SW Permit
8
Difficulty Rating:
21/40
Special Issues Explanation:
• Previously this facility only had an NPDES WW permit for its discharges (NC0004979)
Description of Onsite Activities:
Allen Steam Station is a coal-fired electric generation plant with five active generation units (net
generating capacity of 1,155 NW). The site began power production in 1957. The station includes a
Flue Gas Desulfurization (FGD) facility, a dry ash handling facility, an active ash settling basin, ash
landfill and structural fills, a limestone unloading and stockpile operation, gypsum stacker and
storage operation, a wastewater treatment plant, electrical switchyards, transformer yard, and coal
Page 1 of 10
UALITY
OFFICE

A _
NCS000546 '
handling operation and storage yard. Coal and limestone are shipped to the site via rail lines. '
Documents Reviewed:
0 'NPDES'Stormwater Permit Application Materials (EPA Forms 1 & 217)
0 National Heritage Program (NHP) Threatened and Endangered Species Database
• SPU and NPDES Wastewater Permit Files
• Central Files
0 303(d) List'(2010 Assessment)
0 2010 Catawba BasmWide Plan
'History:
Until' now, the facility has,only had a wastewater permit and sampled some stormwater outfalls as part of the,
NPDES WW renewal application. In' 2'010, Mooresville Regional Office,staff inspected two Duke, Energy
facilities,and noted that this site needed a stormwater permit (see NPDES NC0004979 file). The Division
prefers to issue a separate NPDES SW permit rather than combine wastewater and stormwater requirements
under one permit. The attached permit was drafted to reflect the permitting strategy -for all coal-fired power
plantsrset by the,Stormwater Permitting Unit (SPU) in 2009
Figure 1: Map of Facility
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NCS000546
Central Office Review Summary:
1. Owner's Other Permits:
• NPDES Wastewater Permit NC0004979 1 r
• Air Permit 03757T35
• RCRA Hazardous Waste Permit NCD043678937
• Residual Solids Permit WQ0000452
• Industrial Landfill Solid Waste Permit 36-12
2. General Observations:
In 2009 the Stormwater Permitting Unit (SPU) established a strategy for all coal-fired power
plants. The strategy includes a standard suite of parameters for analytical monitoring (see
attached discussion). Since then, at least four power plants have been monitoring stormwater
discharges for those parameters: Elizabethtown Power LLC (NCS000352), Lumberton Power LLC
(NCS000349), Progress Energy's Mayo Steam Electric Power Plant (NPDES WW + SW
NC0038377), and Progress Energy's Weatherspoon Steam Electric Plan (NPDES WW + SW
NC0005363).
The data from those facilities (12 samples total) shows Zn and Cu benchmarks exceeded most
often. Those sites also have mercury levels in stormwater discharges that range up to 10 ng/1.
3. Impairments and Basinwide Plan Recommendations: The South Fork Catawba River segment is
impaired for copper and has a history of temperature standard exceedances. The Basinwide Plan
(2010) discusses these concerns and references this Duke Energy facility:
"Out of the nine surface temperature samples taken at the lake station during 2007, six exceeded the state
temperature standard. The high temperatures were also recorded at the AMS station C7000000 in 27% of
samples. These co -located monitoring sites are about two and a half miles downstream of the Duke Energy's
Allen Steam Station discharge channel. Figure 4-16 shows the temperature mean and median of the AMS
station C7000000 (blue and red lines, respectively) and the mean and median of five other AMS sites that are
located on Lake Wylie (purple and green lines, respectively). As seen on the graph, the AMS stations average
water temperature is roughly 5'C higher than the other Wylie AMS station averages. Duke Energy conducted a
water quality assessment study to evaluate whether the discharge is having a negative effect on aquatic life,
which is required by the state every five years. DWQ, reviewed the results of the study and confirmed that the
facilities thermal discharge, even though periodically above the state standard, is not negatively impacting
aquatic life. Therefore, this segment will not be Impaired for high temperature.
Copper levels in the South Fork arm are also elevated. Even though this will be the first time this
segment of the lake will be placed on the Impaired Waters list for copper, this exceedance is not new. In
fact, the percent of samples exceeding the standard has dropped from 81% (data years: 1997-2002) to
the current 69% (data years: 2004-2008). The source of the excess copper is likely stormwater runoff
from surrounding urban areas."
The draft permit includes copper monitoring of stormwater discharges from this site. The NPDES
wastewater permit requires a Balanced and Indigenous Population (BIP) study plan be submitted to DWQ
to maintain a CWA Section 316(a) Thermal Variance.
Elevated nutrients are also a concern for Lake Wylie, downstream of this segment of the Catawba River.
This facility is inside the watershed addressed by the Lake Wylie TMDL, and discharges would have been
accounted for in the Load Allocation (non -point sources) at the time. The Modeling and TMDL Unit
recommended infrequent nutrient monitoring to demonstrate there is no problem (per Kathy Stecker,
Modeling and TMDL Unit, April 26, 2011). The draft permit proposes annual monitoring for nutrients,
and the reviewer recommends removing TN and TP monitoring at the next renewal if results
confirm there is minimal concern.
4. Threatened and Endangered: None identified in the vicinity of this site (NHP Virtual Workroom).
Page 3 of 10

NCS000546
S. Location: No issues with locating this facility.
6. Industrial Changes Since Previous Permit: N/A, new stormwater permit.
7. Analytical Monitoring Notes: Two outfalls were sampled as part of the NPDES stormwater application.
These outfalls (SW008 and SW015) were sampled in 2009 for the NPDES wastewater permit renewal
application (submitted December 2009), as part of a prior arrangement with DWQ. Because we have
adopted a consistent stormwater permitting strategy for all power plants, SPU accepted these results
without requiring samples from the other outfalls for the individual permit application. See application
documents (Form 217).
SW008 [Drains area with rail lines that carry coal and limestone; gravel storage area for structural steel,
cable, spare equipment, etc.]: COD levels were elevated (80 mg/1) but not above the 120 mg/1 benchmark.
There were low BOD levels (<2.0 mg/1) in the same sample, which suggests a larger amount of non-
biodegradeable organic material. TSS levels were very high (1500 mg/1) above the 100 mg/1 benchmark.
Aluminum (27.0 mg/1), copper (0.058 mg/1), and zinc (0.32 mg/1) levels were also above benchmarks (of
0.75 mg/1, 0.007 mg/1, and 0.067 mg/1, respectively). Radioactive substances were also reported. There
are no stormwater benchmarks for these substances, but there are water quality standards based on
annual averages. The reviewer noted the level of alpha emitters was around 5 pCi/1 greater than the
standard of 15 pCi/l. No results reported for antimony, lead, or thallium.
SW015 [Drains area west of ash landfill site and gravel haul road for ash transport]: Overall, parameters
were lower in concentration than in the outfall above (except for higher chloride and sulfate
concentrations). All measurements were below benchmarks that were available.
The company is requesting Representative Outfall Status (ROS) for four outfalls. Request form attached.
Central Office observations and questions for Region to consider:
• None of the boxes checked on the ROS form, but groupings seem to be for similar industrial
activities in most cases (according to attached table). Limited data to date.
• Should we require most outfalls to be sampled at least once during the permit cycle? There are
several included in this request that have never been sampled.
• Duke Energy is requesting that SWO05 represent a set of 7+ outfalls, which includes some outfalls
discharging to the Discharge Canal instead of the Catawba River directly (where SWO05 flows). Is
it appropriate for SWO05 to represent Group SWO17 and/or SW019?
• Duke Energy is requesting that SWO18 (to Discharge Canal) represent a set of 4 outfalls, which
includes SW015. SWO15 discharges to a different waterbody (Catawba River) and also drains an
extremely large area (including ash structural fill areas) on the south end of the property. This
outfall was sampled in 2009 (see above), but these are the only data we have from this outfall.
Reviewer recommends considering more data be collected from this outfall before it is included
with a group represented by SW018; does the Region agree?
Wind rose analysis (Tom Anderson, Division of Air Quality, see pg. 5) shows winds are
predominantly from the southwest most of the year here, with more winds from the
northeast in the winter (e-mail follows diagram, pg. 5). This corresponds to winds blowing from
the plant powerhouse towards Drainage Area 8 most of the time, and blowing towards Drainage
Area 11 (comingled with NPDES WW 004) in the winter. Might consider deposition potential
from stacks in these general directions when considering ROS; also consider that the majority of
deposition would occur closest to source. NPDES WW permit only requires flow and 0&G
monitored at Outfall 004 (although SW contribution is small there).
Page 4 of 10

NCS000S46
Email Excerpt
From: Anderson, Tom
Sent: Monday, May 09, 2011 142 PM
To: Georgoulias, Bethany
Subject: RE Wind Roses
Bethany,
Wind distribution in Belmont would probably be well represented by Charlotte NWS data We use MWLOT view
available free here. http //www weblakes com/products/.wrplot/mdex html
I've attached a wind rose that I created for, you for Charlotte The wind distributions, as shown, are almost the same
regardless of the year or time period (5 yr , I Oyr, etc ) at Charlotte Greensboro and Raleigh are very much the
same You can download the program and then use the met.data files that I have attached to look at seasonal or other
periods in detail The sfc files are the ones you'll need — disregard the 'pfl files (they're for "upper air" soundings)
Generally, winds from the SW in late spring, summer and early fall with more winds from the NE in the winter
8 Qualitative Monitoring Notes N/A, new permit
Page 5 of 10

Permit Recommendations:
Analytical Monitoring:
1. Proposed analytical monitoring is consistent with the Stormwater Permitting Unit's strategy for all power
plant permits established in 2009. For more information, see attached discussion. The draft includes:
a. Semi-annual monitoring for 13 priority metals (Ag, As, Be, Cd, Cr, Cu, Hg, Ni, Pb, Sb, Se, Tl, Zn) + Al
& B, with benchmarks where available.
b. Semi-annual mercury (Hg) monitoring with more sensitive method 1631E but no benchmark (or
obligation to monitor monthly in Tier 2).
c. Semi-annual monitoring for COD, TSS, pH, sulfates, and O&G.
d. Requirement to submit annual data summary to DWQ regional office.
2. In addition, the draft permit proposes annual nutrient monitoring because of the Lake Wylie TMDL for
this permit term (should be removed at renewal if there is no concern).
3. Coal pile runoff discharge (subject to stormwater effluent guidelines limitations) is covered under the
plant's wastewater permit (NC0004979); coal yard runoff is directed to NPDES WW outfall 002 (ash
settling basin). Coal yard sump overflow is under the same permit (002a). According to NPDES WW
permit documents, only one discharge has occurred there in the five years prior to NPDES permit renewal
application.
4. The company has requested Representative Outfall Status (ROS) for four (4) stormwater outfalls: SW005,
SW008, SW018, and SW011*. The draft permit does not specify any representative outfalls; review and
approval by Regional Office pending. (See Section 7. for discussion.) *Note that the draft proposes
monitoring SWO11 only once during the permit term because of volume of wastewater there.
Does MRO think it should be monitored semi-annually with the others? Seems like SW011 would
not be very representative if stormwater makes up less than 5% of the discharge flow, even in a
large rainfall event.
Other Proposed Requirements:
1. Because wastewater permit NC0004979 does not include metals monitoring for the discharges through
outfalls 003 and 004, the draft permit clarifies that corresponding SWO12 and SWO11 stormwater outfalls
should be sampled for all parameters in this permit once during the first sampling_ period.
Given that stormwater contributes a small percentage of flow compared to the much larger, continuous
non -contact cooling water and other wastewater flows (4.5 MGD and 6.5 MGD from 003 and 004,
respectively), the potential for contaminants to reach concentrations of concern is probably not very high.
An estimate of stormwater runoff during a large storm (6" in 24 hours) with drainage area and percent
imperviousness showed a stormwater contribution of only —15% of the total discharge flow from SWO12-
003 and —2% of flow from SWO11-004. [The plant does test a 24-hour composite sample from 003 for a
large suite of chemicals for NPDES wastewater permit renewal; however, that sample is usually not taken
during a rain event.]
The one-time sample is intended to screen for possible stormwater problems at these outfalls and confirm
negligible contribution. Any benchmark exceedances would only trigger a Tier 1 response.
Page 6 of 10

NCS000546
Discussions with permittee: Mark McGary, [phone], 5/11/2011, and Don Scruggs (with Plant Allen)
1 Q Two outfalls are,comingled with routine wastewater discharges (not lust emergency overflows)
SW011-004 and'SW012 :003 Are these ever sampled during rain events, and are they sampled prior to
commglmg with stormwater?
a ANSWER 004 (SW011) is sampled quarterly for 0&G, and it,sampled on the first Tuesday of the
quarter—so it may or may not coincide with a rain event Right now there is noway to sample the
discharge prior to commgling with stormwater 003 (SW012) is not sampled except for the
wastewater permit renewal (and probably not,when it's raining) The site is only required to
report flows, which it estimates from pump curves Stormwater runoff contributes a relatively
small volume to these continuous wastewater discharges
b How large is the wastewater flow from each of these outfalls? About 6 5 MGD,max from 004 and
4 5 MGD from 003
2 Q Stormwater that's not routed through oil trap tank in Drainage Area 12—does it bypass that tank?
Where's the discharge sampled?
a ANSWER No bypass, the trap tank is upstream,of the rest -of stormwater "runoff Samples are
taken as close to the end of pipe (outfall) as possible (after cominglmg)
3 Q Where's NPDES Outfall 002 (Ash Settling Basin) - farther south than this plan shows?
a ANSWER Yes To clarify, FGD treatment system flows from mternal,outfall 005 (sampled under
wastewater permit) into these basins There is pH adjustment capability at the settling basins, but
if's not always necessary to use it
Page 7 of 10

NCS000546
SPU Power Plant Permit Strategy (Beginning 2009)
In recent years, the Stormwater Permitting Unit has recognized the complex issues associated with coal-
burmngpower plants and the increased>attention on coal ash storage, use, and disposal,at these sites Data on
stormwater discharges from these plant sites is limited because the focus has traditionally been on
wastewater Regions have also voiced concern about potential ,contamination from metals in stormwater
discharges associated with the activities at these sites After researching constituents these activities or
materials may introduce to the power plant property (and with them potential for stormwater pollution), the
Unit formulated a;strategy for these renewal permits
Basis Draft RTI Study ('Human and Ecological Risk Assessment of Coal Combustion Wastes, RTI, August
2007) and 4iscussions with Robert Schreusdale of RTI suggest these metals may, signal contamination
problems SPU also discussed contaminants with Duke University researcher, Dr Avner Vengosh, who
researched the TVA ash, pon'd'spill in Dec 2008 in Kingston, TN (Mtg with SPU on May 4, 2009) In
addition, RRO/DWQ has sampled dischargesfrom cogeneration plants in the FRO area and flagged
metals of concern Overall, we have very little data with which to characterize storm water discharges
from this industry, but we know there is a concern and need for better understanding aboutpossible
stormwater pollution from activities here
(FYI - Cost of clean mercury method around $160)
Basis Power plants area potential mayor source of mercury, and although some Hg may be regional,
there is a risk that significant quantities come from the activities at the plant itself While wastewater
permit,limits are calculated based on low stream flow and high, wastewater effluent flow conditions—
and sometimes do not warrant the lower -detection method—stormwater contributions vary broadly
and do not change the bio -accumulative nature of methyl -mercury SPU recognizes the complexity of
regional air transport and deposition, as well as the cost and resources involved in clean mercury
sampling protocol, and therefore will exempt Hg from monthly monitoring in the tier structure
However, if mercury data suggest a problem driven by sources or activities at the plant, DWQ should
investigate further and could require,additional monitoring in the future
• emiLannual monitorin��forCOD. Trs.,. pH. sulfates, and O&G.
Basis conventional pollutants associated with types of activities here Note -include provision to allow
pH values below benchmark if facility can document rainfall.pH is as low or lower at "time of sampling
Basis Consistency with current draft General Permits and to facilitate prompter awareness of
monitoring results at -the regional office level
Page 8 of 10

NCS000546
example, plants might consider installing bioretention cells for,drainage areas where metals are a
problem and monitor for effectiveness, in exchange for decreased monitoring frequency and/or no
benchmark trigger We will also` consider relieving monitoring if the facility can demonstrate levels
are not attributable to, or else not able to be separated from, industrial,activities SPU will work with
the regional offices to address, situations on a case-by-case basis
Basis SPU recognizes the ubiquitousness of copper and zinc, and the low benchmark concentrations for
metalslike Cd, but we also know activities at power plants can be contributors of these pollutants SPU
feels alternatives to more monitoring can facilitate solut►ons,and that the permit t►erstructure isflexible
enough to relieve the permittee of monitoring when appropriate
ermit examine for needLto aDDlueriPlimit$. Federal effluent guidelines apply
specifically to the Steam Electric Generating industry, which excludes cogeneration facilities
However, cogeneration plants are similar in many respects, and coal storage and handling activities
may even be identical SPU will consider'a,tailored approach for certain SDOs based on proximity°to
coal sources, storage area size, etc Depending on the size and similarity of the coal storage and
handling (and perhaps other factors), the permit writer could decide to (a) apply limits'initial'ly, or (b)
an arrangement where benchmarks mirroring BPT requirements for coal pile leachate in 40 CFR §423
(TSS of 50 mg/l and pH 6-9 SU) would become limits after two exceedences (i e, Tier 2 action), or (c)
lust impose benchmarks
Basis- Federal stormwater,effluent limits apply to coal piles at steam electric generating facilities,
similarity of cogeneration plants (and even elsewhere) warrant similar scrutiny Otherstates such as
Virginia, Ohio, and Georgia have�already imposed the same BPT limits on coal pile runoff and leachate at
facilities where coal burning for steam, electric generation is notnecessar►ly the primary industrial
activity The flexibilityfor North Carolina to do the same follows that,lead and acknowledges the
potential for the same pollution problems
Page 9 of 10

NCS000546
Recommendations: Based on the documents reviewed, the application information submitted on February 21, 2011
(fee submitted March 3, 2011) is sufficient to issue an Individual Stormwater Permit.
Prepared by (Signature)
Stormwater Permitting'
Date 51-f -2-1-m i
Date s / ZoGf
Concurrence by Regional Office Date 3
RO Water Quality Supervisor t Date
Regional Office Staff Comments (attach additional pages as necessary)
Page 10 of 10

To Bethany Georgoulias July 13, 2011
From Rob,Krebs
Prepared By Michael Parker/R7
NCS000546 Luke Energy Carolinas, LLC - Alden Steam Station
Gaston County
Site inspection conducted on July 13, 2011, by Michael Parker Facility contact Mr Mark McGary
[phone] (cell) and Mr Don Scruggs, Plant Manager This request `is for a new SW permit
This facility is in the business of producing electricity via coal fired turbine generation The S W
outfalls at this site drain to both Lake Wylie and to the South Fork Catawba River Both Lake Wylie
and the, South Fork are classified as WS -IV, B The South Fork is listed as impaired for copper and
has documented water quality standard exceedances for temperature
A significant portion of the SW generated from the industrial process areas at,the Allen Steam Station
site is routed through existing yard drain sumps that carry the SW to an existmg,ash basin This ash
basin discharges through outfall 002, which is covered under the facilities existing NPDES wastewater
permit (NC`0004979) There are, however, areas of the site where SW drains back to surface waters,
and these areas (and the associated outfalls) are to be covered under the subject SW permit The only
SW testing data available for review -in this application was collected in 2009 at SW outfalls'SW008
and SW0015. This data was collected in conjunction with the site's NP DES wastewater permit
renewal There are at least 20 existing SW outfalls that Duke Energy has submitted for inclusion into
the proposed permit Some of these outfalls are relatively easy to access and some are very difficult to
access There ,are a few outfalls ,that would likely present a safety issue foi site personnel should
analytical be required' Also observed during the site visit°were a number of "internal" SW outfalls that
do not discharge directly off-site and' may require some channel modifications ,in order to collect a SW
sample A number of these internal outfalls discharge into vegetated areas as sheet flow before,
reaching surface waters There are also a number of outfalls identified in the permit application that
were found during the site visit that drain areas of the site that are well removed from where any
industrial activities take place These outfalls should not be included as sampled outfalls and are
identified on the site map as outfalls SW001, SW002, SW013, SW014, SW017, SW019, and SW020
In their permit application, Duke Energy has requested the following outfalls be considered as
Representative Outfalls
o Outfall SW005 as representative of outfalls SW002, SW004_, SW005, SW006, SW014, SW017,
and Group outfalls SW019
Based on observations made during the site visit, designating outfall SW005 as a
Representative Outfall is considered appropriate for this group of outfalls even though outfalls
SW017 and SW019 enter the discharge canal°instead of the Catawba River As noted above,
SW outfalls SW017 and SW019 do not drain areas associated with the industrial activities at
this site, so it would be acceptable to include them in this representative group

Page Two
o Outfall SWO08 as representative of outfalls SW001, SW003, 8WO07, SWO08, SWO09, SWO10,
and Group outfalls SWO13
Designation of outfall SWO08 as iepresentative of this group of outfalls is recommended
® Outfall SWO18 as reptesentative of outfalls SWO15, SWOzl�6, SW01,8,,and SWO20
Drainage area 18, which leads to outfall SWO18 is one of the areas of this site where°internal
outfalls complicates the review of this request Furthermore, there is a perennial channel that "
bisects drainage,area L8, and separates the drainage area into two distinct areas" Since all SW
from drainage area 18 leaves the site at the confluence of the perennial channel and the
discharge canal (SWO18), it would not be prudent to conduct analytical testing at this outfall
since any testing would not be entirely representative of the SW from this drainage area 18 due
to the possibility of off-site influences The western portion of this drainage area is
predominately wooded with some gravel parking areas whose `SW is directed via sheet flow
back towards_the perennial channel The SW from the eastern portion, of this drainage area
travels through at`least two internal outfalls, a closed out (vegetated) sediment basin, and then
sheet flows down towards the perennial channel The SW from the small amount of industrial
activities that takes place in this drainage area (Dry Ash Handling Facilities) is collected and
piped back to the site's existing ash basin In conversations with Duke Energy staff during the
site visit, rt°was decided that outfall SWO15' would be,a more representative outfall than
SWO18 This decision was based on the large size of the area that drains to the outfall, t`e fact
that the SW from this area drains an area where fly ash has been deposited, and the fact that any
discharge from SW015 is comprised of SW from the site and riot influenced (significantly) by
off-site drainage This Office recommends that outfall SW0I5 be designated as representative
of outfalls SWO16, SWO18, and SW020
• Outfall SWO11 is representative of outfalls SWO11 and SWO12
The drainage areas for both outfalls SWO11 and SWO12 are two drainage areas where a
significant amount of the industrial activities at this site take place In both of these areas, there
are both graveled and paved (impervious) areas, and a portion,of the SW generated in these
drainage areas passes through oil trap tanks (oil/water separators) before being discharged
Based on observations made during the site visit, this Office,has no objection to, designating
SW outfall SWOT I as representative of outfalls SWOT I and SWO12, however, analytical testing
for all parameters should be required of both outfalls during the first sampling period of the
permit
SW outfalls SWO05, SWO08, and SWO11 receive drainage from areas that have areas that are either
partially graveled or receive a consideiabl'e amount of vehicular traffic Fines associated with the
gravel and vehicular traffic will likely be problematic for TSS once analytical testing begins Unless
additional measures are implemented to control the off-site movement of the fines associated with the
gravel and dust from vehicular traffic, this facility will likely have difficulty in consistently complying
with the benchmark TSS levels proposed in the draft SW permit The mobility of these particles may
also help contribute to the other elevated benchmark values noted in the analytical testing data
submitted with the permit application

Page Three
Analytical testing data, collected in 2009, and submitted with the permit application for outfalls
SW008 and SW015 reflected a number of parameters where test results have exceeded the proposed
benchmark valucs for Aluminum, Clvomium, Copper, Zinc, and Total Suspended Residue Given the
large areas of gravel throughout the site, it 1s not surprising that the TS levels, would be elevated,
however, Duke Energy staff will need to conduct an internal investigation to determine possible
sources of the elevated aluminum, copper, and zinc levels There have been some significant
construction additions at this site since the 2009 testing was performed, and these activities could result
in a change in the characteristics of the site's SW, which would render the submitted testing data as not
being indicative of current site conditions One important site addition in recent years is the
construction of the Flue Gas De-Sulfurization facilities (FGD), which have now been completed and
placed into operation As a result of the construction of these air treatment facilities, Duke no longer
has a "particulate" discharge, but releases steam as a by=product from the FGD operation' Such being
the, case, it will not be necessary to consider a possible wind rose deposition analysis in the selection of
potential representative outfalls since Duke no longer releases particulates to the atmosphere,
Even though representative outfall status has been requested for a number of the SW outfalls at this
site, the lack of'(recent) analytical testing data is of a concern, especially when some of these outfalls
drain areas of the site where signr`ficant industrial activities take place Granted some of these outfalls
can be considered consistent in nature with their corresponding representative outfall, however, the
screening of these outfalls will provide beneficial data in Which to base future permitting decisions and
help confirm any negligible pollutant loading Such being the case, it is recommended that analytical'
testing be performed for all parameters during the first sampling period of the permit at SW outfalls
SW002, SW007, SW008, SW009, SWO10, and SW012
In conclusion, it is recommended that the,subject SW permit be issued with consideration given to the
commentshecommendations as contained.m this report
/mlp
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