(<.( c e,wd cr /g;; r/' 

f. DUKE 

ENERGY® 

September 4, 2015 

Howard Shelanski, Administrator 

Office of Information and Regulatory Affairs 

Office of Management and Budget 

725 17th Street NW 

Washington, DC 20503 

DIANE V. DENTON 

Director 

Environmental & Energy Policy 

526 S. Church Street 

EC12K 

Charlotte, NC 28202 

Tel: 704-382-8598 

diane.denton@duke-enerr;y com 

Subject: Effluent Limitations Guidelines and Standards for the Steam Electric Power Generating 

Point Source Category (RIN: 2040-AF14) 

Dear Administrator Shelanski: 

Duke Energy Business Services, LLC (Duke Energy), on behalf of Duke Energy Carolinas, LLC, 

Duke Energy Indiana, Inc., Duke Energy Ohio, Inc., Duke Energy Kentucky, Inc., Duke Energy 

Florida, Inc., and Duke Energy Progress, Inc. is writing to you to express our concerns 

regarding the Effluent Limitations Guidelines and Standards for the Steam Electric Power 

Generating Point Source Category (RIN: 2040-AF14) currently under review by the Office of 

Information and Regulatory Affairs (OIRA). Duke Energy is the largest electric power holding 

company in the United States with more than 51,400 megawatts of generating capacity. We 

serve 7.3 million U.S. electric customers located in the Carolinas, the Midwest and Florida. 

Duke Energy supplies reliable and affordable electricity from a diverse mix of coal, nuclear, 

natural gas, oil, hydroelectric, and renewable resources. As such, the outcome of this 

rulemaking proceeding is very important to Duke Energy and its customers. 

As a member of the Utility Water Act Group (UWAG)\ Duke Energy participated in meetings 

between UWAG and OIRA on August 6 and 12, 2015 in which concerns regarding the proposed 

flue gas desulfurization (FGD) limits and bottom ash transport water limits were discussed. 

Duke Energy supports the proposed UWAG alternative approaches for those limits, but would 

also like to express concerns with the rule that have not been previously discussed. These 

additional concerns are related to: 

1. Limits for Integrated Gasification Combined Cycle (IGCC) Wastewater 

2. Anti-circumvention Measures 

3. Sufficiently Sensitive Measures 

4. Fixation as a zero liquid discharge system 

Duke Energy previously communicated these concerns to EPA as part of the comments on the 

proposed rule submitted by Duke Energy on September 19, 2013. 

1 The Utility Water Act Group is a voluntary, ad hoc, non-profit, unincorporated group of 198 individual 

energy companies, which own and operate over fifty percent of the nation's total generating capacity. 

Duke Energy is a UWAG member, as are the Edison Electric Institute (EEl), the American Public Power 

Association (APPA), and the National Rural Electric Cooperative Association (NRECA). 
~-----------------------------

1. Limits on IGCC Wastewater 

There is an extremely limited data set on wastewater from IGCC facilities. Only four IGCC 

facilities are located in the U.S., with one- the Kemper Station- not yet fully operational. The 

designs and byproducts of these facilities are significantly different. Duke Energy believes that 

EPA cannot properly establish limits for the IGCC waste stream subcategory in this rulemaking 

based on such limited data. Further, because there only four facilities in the U.S., it is 

unnecessary to establish national effluent guidelines at this time. Duke Energy, therefore, 

requests the IGCC waste stream subcategory be removed in the final rule. 

EPA proposed to include gasification wastewater from IGCC facilities as a new waste stream 

subcategory within the rule. For IGCC wastewater, EPA proposed the following limits: 

Parameter Daily Max. 30-day average 

Arsenic (1-Jg/L) 4 N/A 

Mercury (ng/L) 1.76 1.29 

Selenium (IJg/L) 453 227 

Total Dissolved Solids (TDS) 

(rn_g/1...) 38 22 

Under the proposed rule, these limits applied to all wastewater from all sources at an IGCC 

operation except those for which specific limitations are otherwise established. 

In Duke Energy's comments on the proposed rule, we recommended that EPA reserve setting 

effluent limitation guidelines for IGCC wastewater for a later rulemaking for the following 

reasons: 

Extremely limited data for IGCC stations 

The proposed limits are based on very sparse data incorporating the performance of the 

only two IGCC systems (Wabash River Combined Cycle Plant (Wabash River) and Polk 

Power Station (Polk)) in operation within the United States at the time of the proposed 

rule's development. The data set was comprised of only four samples from each of the 

two plants. Moreover, for each of the two plants, the four samples were taken on four 

days within a single calendar month. From this already limited data set, EPA discarded 

the arsenic and mercury data from the Wabash River facility for use in the statistical 

analysis and limitation development. As a result, the effluent sample results for arsenic 

and mercury are limited to a single calendar month (and actually a single four 

consecutive-day period) from a single plant. 

IGCC Facilities Have Significant Differences in Design 

Currently, there are only four IGCC facilities located in the United States, with the 

Kemper Station not yet fully operational. These facilities have significant differences in 

their design and the byproducts they produce, both of which affect the composition of the 

wastewater. As an example, the three stations currently in service (Duke Energy's 

Edwardsport, in addition to Wabash River and the Polk Power Station) burn a different 

blend of fuel (e.g. pet coke, pet coke/coal blend, and coal), which can result in variability 
of constituents and concentrations in the grey water system. Additionally, these stations 

generate different commercial byproducts: for example, Polk produces sulfuric acid, 

while the Edwardsport IGCC produces elemental sulfur. Even EPA acknowledged that 

the two facilities used in their evaluation, Polk and Wabash River, "operate slightly 

different processes, [and] they are not the same waste streams at both plants."

2 

Duke Energy's Edwardsport IGCC facility is the newest plant in the country with state-of-the-art 

technology. However, since the Edwardsport facility was not yet in operation at the time EPA 

collected the data that was subsequently used to establish the limits for arsenic, mercury, 

selenium and TDS, any relevant influent/effluent and operational data were not incorporated into 

the proposed limits. Upon commencement of operation of the Edwardsport IGCC facility, 

effluent data was collected as required by the National Pollutant Discharge Elimination Systems 

(NPDES) permit. This data is presented in the following table. Based on this initial data 

collection effort, Edwardsport may be challenged to meet the mercury limits for the IGCC waste 

stream subcategory, if the rule is finalized as proposed. It is also important to note, due to 

analytical variability and potential sample contamination, any sample collected from any source 

may be challenged to meet the extremely low mercury limits presented in the proposed rule. 

Edwardsport Outfall 501 (Greywater Treatment Effluent) 

Sample Arsenic, Mercury, 

date ug/1 Selenium, ug/1 ng/1 

5/9/2013 <0.06 7 

5/23/2013 <0.06 0.2 

6/6/2013 <6 <0.2 

6/13/2013 <6 <0.2 

7/22/2013 2.08 

7/24/2013 2 4 

7/31/2013 <0.6 <0.2 

8/2/2013 <0.6 <0.2 

8/8/2013 9.58 

8/25/2013 15 <0.2 

9/5/2013 <0.06 <0.2 

9/25/2013 <0.06 <0.2 

10/3/2013 2.53 

10/8/2013 <0.6 <0.2 

10/17/2013 <0.6 <0.2 

• 

2 78 Fed. Reg. at 34484 
2. Anti-Circumvention Measures 

EPA proposed to add provisions to the regulations that would prevent facilities from, in EPA's 

terminology, "circumventing" the newly proposed effluent limitations and standards for 

wastewaters containing coal combustion residual (CCR) constituents. These would require 

facilities to (1) demonstrate compliance before using the waste stream in another plant process 

or mixing the waste stream with another waste stream; and (2) not transfer effluent with a zerodischarge standard to another process with less stringent requirements. Both of these 

provisions are contrary to EPA's goal of encouraging centralized waste treatment systems. 

Further, these provisions will discourage recycling and reuse of treated wastewater. 

Centralized Waste Treatment Systems 

EPA stated in its 1980 Steam Electric Technical Development Document that 

"consolidation of waste streams to a centralized treatment system is permitted and 

encouraged." The 1974 preamble to the steam electric guidelines says much the same 

thing: "It is also recognized by EPA that, due to the economies of scale, combining 

similar waste streams for treatment to remove the same pollutants is generally less 

cosUy than separate treatment of these waste streams. The employment of cost-saving 

alternatives in meeting the effluent limitations should not be discouraged." If steam 

electric utilities are prohibited from co-mingling waste streams prior to treatment, multiple 

waste treatment systems may have to be built, one for FGD wastewater, one for 

chemical/non-chemical metal cleaning wastewater, one for 11ow volume wastewater, etc. 

Duke Energy believes the condition to demonstrate compliance prior to .mixing with other 

waste streams is counterproductive to EPA's goals and should be rer-Qoved in the final 

rule, especially if the model treatment technology ,includes the same components for 

different waste streams. This would be the case for chemical metal cleaning wastewater 

and FGD wastewater, as the model technologies for both of these waste streams are 

expected to include similar physical/ chemical treatment. 

Recycling and Reuse of Treated Wastewater 

If the anti-circumvention measures are finalized as proposed, there will be no incentive 

to recycle or reuse treated wastewater. For example, Duke Energy's Edwardsport facility 

rarely discharges wastewater from the grey water system. This water is recycled within 

the cooling towers and is only discharged when the unit goes offline. Under a strict 

interpretation of the anti-circumvention measures, this water must meet the IGCC limits 

prior to mixing with any other waste stream, which completely discourages recycling of 

wastewater. 1n addition, under a no discharge limit of bottom ash transport water, the 

anti-circumvention measures prevent treated bottom ash transport water to be used as 

FGD scrubber make-up water. Allowing reuse of bottom ash transport water as scrubber 

makeup water would be an effective management practice for maintaining a bottom ash 

recycling system, while effectively treating any metals .in the bottom ash transport 

system through the FGD wastewater treatment system. Recycling of wastewater would 

reduce the amount of water withdrawn for FGD scrubber make-up water. 
EPA's proposed anti-circumvention measures are in direct contradiction of the centralized waste 

treatment goal and discourage reuse and recycling of water. As a result, the anti-circumvention 

language should be removed in the final rule. If EPA is concerned utilities will not install the 

model technology for the waste stream, these concerns can be addressed on an individual 

permit basis as opposed to establishing national requirements that discourage water 

conservation. 

3. Sufficiently Sensitive Methods 

EPA proposed to include a requirement for utilities to use "sufficiently sensitive analytical 

methods." While Duke Energy understands EPA's rationale to include this provision in the 

proposed rule (i.e., to minimize undetected exceedances of the limits) the language is 

unnecessary as it is duplicative of EPA's final Suff·iciently Sensitive Methods rulemaking (79 

Fed. Reg. 49,001 (August 19, 2014)), which was finalized almost a year after the close of the 

comment period on this rule. Including specific provisions requiring sufficiently sensitive 

methods in the steam electric ELG while at the same time EPA has promulgated a separate, 

comprehensive Sufficiently Sensitive Methods rule could cause confusion and lead to contl,icting 

requirements, especially for FGD wastewater. 

Obtaining accurate data from FGD wastewater samples is subject to numerous variables that 

include different sampling methods, sample preservation procedures, types of analytical 

instruments, lab procedures and varying degrees of lab experience. These issues were 

acknowledged in the memorandum from James A. Hanlon to Water Division Directors, Regions 

1-10, "National Pollutant Discharge Elimination System (NPDES) Permitting of Wastewater 

Discharges from Flue Gas Desulfurization (FGD) and Coal Combustion Residuals (CCR) 

Impoundments at Steam Electric Power Plants" (June 7, 201 0). In addition, the EPA approved 

analytical method for metals, Method 200.8, as written, is not sufficiently detailed to analyze the 

FGD matrix and to detect to the levels of the proposed limits. 

As currently drafted, the language in the proposed rule is inconsistent with the Sufficiently 

Sensitive Methods rule. Unlike the Sufficiently Sensitive Methods rule, the proposed "sufficiently 

sensitive" provision is not limited to 40 CFR Part 136-approved methods. Thus, the proposed 

provision could require the use of unapproved analytical methods that have not undergone 

EPA's validation process and may be unreliable since there are few, if any, approved methods 

capable of measuring at the low regulatory limits proposed in the rule. The proposed "sufficiently 

sensitive" provision could be interpreted as allowing or even encouraging the use of unapproved 

analytical methods in contradiction to the Sufficiently Sensitive Methods rule. 

Duke Energy contends that compliance sampling should be based on re'liable and well-defined 

analytical methods and EPA should remove the requirement to use "sufficiently sensitive 

analytical methods" from the rule, or at a minimum clarify the final rule only authorizes the use of 

analytical methods approved under 40 CFR Part 136 consistent with the final Sufficiently 

Sensitive Methods rule. 

.. 
4. Fixation as Zero Liquid Discharge 

Fixation is an effective way to treat and dispose of FGD wastewater. Fixation involves the 

mixing of lime, fly ash and FGD wastewater with FGD solids (calcium sulfite) separated from the 

purged slurry to form a cement-like substrate. Through pozzolanic reactions that occur in the 

mixture, dissolved solids, metals and chlor·ides in the FGD wastewater are bound in the cementlike substrate, which would be disposed of in a landfill. This approach to fixating waste is useful 

for landfiU disposal due to forming a near-impermeable mass, which resists liquefaction, thereby 

minimizing the leaching of constituents. This treatment option is suitable for stations with an 

inhibited oxidation FGD scrubber, which does not produce saleable gypsum. For stations that 

choose to install a fixation system, these systems are very effective at treating FGD wastewater 

and result in no discharge. 

EPA Region I evaluated fixation as a best available technology in support of the reissuance of a 

NPDES permit for Merrimack Station (Permit No. NH0001465). In EPA's Steam Electric Power 

Generating Point Source Category: Final Detailed Study Report, a case study for Ohio Power 

Company's General James M. Gavin Plant was presented as an example of a zero discharge 

system for FG D wastewater. This treatment system is similar to the fixation process in which a 

cementitious material 1is generated and placed in a landfill. 

It is essential EPA acknowledge fixation in the final rule as an effective treatment system and 

clearly state this treatment system results in zero liquid discharge of FGD wastewater. This is 

necessary to avoid misinterpretation by state environmental regulatory agencies during 

implementation of the rule. 

Thank you for reviewing our concerns on the rule. As stated previously, the outcome of this 

rulemaking proceeding is very important to Duke Energy and its customers. 

Should you have any further questions regarding these concerns, please contact Jennifer 

Stenger at Jennifer.Stenger@duke-energy.com (727-826-5628) or Nathan Craig at 

Nathan.Craig@duke-energy.com (704-382-9622). We also welcome an opportunity to meet with 

OIRA to further discuss these concerns. 

Sincerely, 

Diane V. Denton 

Director of Environmental and Energy Policy 

cc: 

Dominic J. Mancini, Deputy Administrator 

Jim Laity, Branch Chief 

Vlad Dorjets, Desk Officer