October 30, 2014 Thomas Effinger SCAN A UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON, D.C. 20460

220 Operations Way Mail Code: C221 Cayce, SC 29033-3701 Dear Mr. Effinger: OFFICE OF WATER

The U.S. Environmental Protection Agency ("EPA"), under the authority ofthe Clean Water Act, as amended (the "Act"), 33 USC 1251 et seq., proposed revisions to the effluent limitations guidelines and standards ("ELGs") for the steam electric power generating point source category on June 7, 2013. EPA received the comments submitted by SCANAregarding the proposed ELGs on September 20, 2013. Those comments discuss a pilot treatment technology program that was implemented at SCANA's Wateree station in June 2013 , and they present some results from the program. Based on our review ofSCANA' s comments, as well as those ofthe Utility Water Act Group ("UWAG"), which SCANA expressly endorses, we have concluded that additional information is needed to evaluate the data provided in SCANA's comments, as well as comments with respect to flue gas desulfurization ("FGD") wastewater characterization and tr· eatment. Thus, pursuant to Section 308 ofthe Act, 33 U.S.C. 1318, EPArequests that you provide the Agency with all FGD wastewater and pilot-scale FGD wastewater treatment datathat was collected from SCANA's Wateree Station during the pilot testing programreferenced in the comments. The following identifies EPA's specific requests/questions related tothe pilot tests conducted at SCANA's Wateree Station

. 1. Please identify when the pilot testwas conducted.
2

. Please identify and describe the objectives ofthe pilot test. 3. Please provide a description ofthe wastewater used in the pilot testing (e.g., describe any treatment ofthe FGD wastewater prior to 

### it being transferred to the technologies evaluated aspart ofthe pilot testing).

Internet Address (URL) • http://www

.epa
.gov Recycled/Recyclable • Printed with Vegetable Oil Based Inkson 100% Postconsumer, Process Chlorine Free Recycled Paper4. Please describe any changes made to the pretreatment configuration/operations during the pilot testing and when these changes occurred. For example, describe any additional pretreatment steps that were added prior to the wastewa ter being transferred to th e pilot-test technologies. Include a detailed description of the pretreatment technology (or changes to the technology) including chemicals and dosage rates, and the date the changes were made. Fo r any changes made to the pretreatment system, pro vide an explanation as to why the changes were made. 5. Please provide a description of all the wastewater trea t ment technologies evaluated as part of the pilot testing, including all biological (e.g., G E 's ABMet, Infilco's iBio) and other treatment systems (e.g., chemical precipitation, ion exchange, ultrafiltration, vapor -compression evaporation, zero valent iron) including chemicals and dosage rates. Please also note any changes made to the treatment technologies or additional pretreatment added by the vendors to the systems during t he pilot testing to

optimize performance of the technology. For any changes made to the treatment technologies, provide an explanation as to why the changes were made and identify the date the changes were made. 6. Please identify the amount of wastewater treated through each of the treatment technologies (including any pretreatment system(s)) and note any changes throughout the pilot test duration. For any changes in the wastewater flow rate treated, please explain why there was an increase/decrease in the flow rate. 7. Please identify any wastestreams or dilution streams that were/are commingled with the FGD wastewater prior to treatment technologies. Identify the percent contribution of the other wastestreams/dilution streams compared to the FGD wastewater that was/is treated in the pilot test. 8. Please provide a s implified process flow diagram of the entire pilot test configuration that identifies t he generation of the FGD wastewater, any pretreatment systems, and

all technologies evaluated. Please note that th is simplified diagram should identify the operation of the pilot test before and after any changes were made and the date changes were made should be noted on the diagram. See Enclosure 1 for an example of a simp lifi ed process flow diagram. 9. Please provide a detailed process flow diagram for each wastewater treatment technology evaluated as part of the pilot testing including any vendor installed pretreatment steps starting with the wastewater supplied to the vendor by AEP. The diagram should show all the specific samp ling locations and chemical addition pointsfor that technology. Please note that each diagram should include specific sampling . location names sothe analytical data can**b~** matched specifically to each technology evaluated. See Enclosure 1 for anexample ofa detailed process flow diagram. 10. EPArequests that SCANAprovide all arsenic, mercury, selenium, nitrate/nitrite, and ammonia concentration data for the following wastestreams for the entire time period that the pilottest was conducted (see Enclosure 2 and Attachment 1 ("Analytical Data Table" workbook) for details on providing the analytical data): a. FGD purge stream (e.g., prior to any treatment ordilution); b. FGD purge intermediate- Primary (e.g., FGD purge after first pretreatment step); c. FGD purge intermediate- Secondary (e.g., FGD purge after second pretreatment step); d. FGD purge intermediate- Tertiary (e.g., FGD purge after third pretreatment step); e. FGD purge intermediate- Quaternary (e.g., FGD purge after fourth pretreatment step); 

### f. Influentto pilot testing (e.g., after all pretreatment, butbefore treatment inthe technologies evaluated in the pilot test); and g. Treated wastewater from each technology evaluated (Note: Ifany technologies are operated as treatment trains (i.e., one technology is downstream ofanother technology) then the data for each stage in the treatment train should be provided). 11. Additionally, EPA requires certain supplemental information to further evaluate the quality ofthe data. Please provide the data listed inEnclosure 2.
12. Please provide the type and source ofcoal (i.e., mine name and location) used at the plant each day starting one monthprior to the beginning ofthe pilot test and continuing through the entire pilot test duration. 

### Inaddition, please provide the sulfur and chlorine content ofthe coal used at th e plant for each day ofthis period, if available. Fordays where coal blending occurred, please note the percentage ofeach type ofcoal used. See Attachment 2 (Supplemental Dataworkbook, tab titled "Coal Data") for the format ofthe data requested by EPA. 13. Please provide the following information for each day within the range ofsampling results that are being provided, ifavailable (See Attachment 2 Supplemental Data workbook): a. Chloride concentration, pH, total suspended solids (TSS), and average daily oxidation-reduction potential (ORP) values within the FGD scrubber system (tab titled "FGD System Information"); b. Chloride concentration, pH, TSS, and average daily ORP values for the FGDpurge stream (prior to any treatment) (tab titled "FGD Purge Stream"); c. Chloride concentration, pH , TSS , and average daily ORP values for the influent to · pilot testing (e.g., after initial treatment , but before treatment in the technologies evaluated in the pilot test) (tab titled "FGD WWT Influent"); and d. Electric generation output (MW-hr) for each generating unit serviced by a FGD system (tab titled "Electricity Generation").

Additionally , EPA requests that you identify all other pilot tests conducted between January 1, 2010 and the present that evaluated the treatment ofFGD wastewater at Wateree Station or any other SCANA power plants. For each of the additional pilot test identified, you must provide the following information: • Where was the test conducted; • When was the test conducted; • What technologies were evaluated (company and technology); and • What were the objectives of the test ? The information and data responsive to the items above should be received by EPA !!Q later than November 21,2014. EPA has determined that it requires such information and data in order to assist with the development of its revised steam electric ELGs , and the Agency is under a consent decree to sign a decision taking final action on the rulemaking by September 30, 2015. The Agency also believes that all the information and data requested is readily available to SCAN A, and thus EPA's request is reasonable. You must prov i de the information and data to E PA pursuant to the federal law cited abo v e. Moreover, it is in your best interest to ensure that any information on which EPA may base its regulations presents an accurate and representative picture of the industry . We appreciate your coop e ration in providing all the information and data requested. Please be advised legal action, resulting in penalties, could be taken against you should you fail to fully cooperate with this request. Enclosure 1 of this letter provides example process flow diagrams that should be provided in response to this request. Enclosure 2 of this letter provides details regarding how the analytical data and supplemental information should be provided to EPA. Enclosure 3 of this letter provides the statutory authority on which this request is based and explains your legal rights to protection of confidential business information. Enclosure 4 is a notice of EPA ' s intention to allow selected contractors access to all information, including confidential information that you submit. EPA will make your information available to EPA contractors to the extent they need such information to carry out any work required by their contracts. As noted in Enclosure 4, if you wish to comment on this action, any such comment must be received in writing by E PA within 10 days of your receipt of this notice. Please send these comments to the address li sted in Enclosure 4. If you have any questions or concerns , please contact Phillip Flanders via e-mail at flanders.phillip @ epa . gov or by phone at 202-566-8323.We appreciate your help inproviding the information described above ina timely manner. Sincerely,



# yQh **~** Robert K. Wood, Di rector Engineering 

### & Analysis Division (4303T) EnclosuresEnclosure

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le Simplified Process Flow Diagram for Pilot Test ConfigurationTechnology2Technology2Technology2Technology2InfluentEqualizedInfluentAdded6115114PretreatedInfluentTechnology2Bioreactor1EffluentBioreactor2EffluentPlant-SuppliedWastewatertoVendorEqualizationTankI:---------------------------------,IIlFerric!II:LimeChloridePolymer:II:IIIl:IIl:II!Rct·SettlingTanklIea1on(CI·t·Tankan1erSimulation)Solids---------------------------------'NutrientsBiologicalReactor1NutrientsBiologicalReactor2Figure2.ExampleDetailedProcessFlowDiagramforPilotTestTechnologyIIIIIIIPolishingFilterTechnology2FinalEffluentIIIIIIIEffluentEnclosure 2 Guidelines for Submitting Analytical Data for the Steam Electric Power Generating Effiuent Guidelines Rulemaking This document provides guidance regarding the submission of analytical data in response to the proposed Steam Electric ELGs, inc l uding the type of supplemental information that should be provided along with any analytical data, in order to ensure that EPA can use the data to inform its analyses for the final action. The data you submit should reflect typical operating conditions and be representative of properly operating treatment systems. Data you submit should be relevant to flue gas desulfurization wastewater. Important Considerations • The data provided should include both treated, partially treated, and untreated wastewater. • Pollutant data should be collected using sufficiently sensitive, EPA - approved analytical methods in 40 CFR Part 136 appropriate for the pollutant concentrations present in the wastewater. Data Submission Format and Criteria

To facilitate EPA's analysis and use of the analytical data , the data should be submitted using the format provided in the Microsoft Excel Workbook titled "Analytical Data Table. " The Analytical

Data Table workbook provides the content , structure, and format for the analytical data submission. Included within the workbook are two separate spreadsheets. The spreadsheet titled "Data Table Structure" provides the table for entering the analytical data. The spreadsheet titled "Example Data Table" includes three example entries to provide some context of how to

populate each of the fields in the data table. Additionally, the spreadsheet titled "F ield Descriptions " describes each fie l d included in the data table. Provide the individual sample results associated with the sampling locations. Entries that average multiple results for a sampling point are of limited use. The following is the information that should be provided for each individual sampling result, as applicable (see the "Field Descriptions" spreadsheet for more details): • Plant Survey ID (from the Questionnaire for the Steam Electric Ejjluent Guidelines); • Plant Name; • Date Sample Collected; • Analyte (for metals , inc l uding whether it is total recoverable or dissolved); • CAS Number; • Analytical Method; • Type of Sample Collected (e.g., grab, 24-hour composite); • Type of Sample Analyzed (e.g., total recoverable, dissolved) • Units; • Non-Detect Indicator; • Concentration;• J-Value Concentration; • DetectionLimit; • Reporting Limit; • Dilution Factor; • Qualifiers; • Qualifier Description; • Wastestream represented by result; • Flow rate; and • Samplepoint description. ForEPA to evaluate whether the dataprovided are valid and ofsufficient quality for use inthe loadings analyses and/or limitations development, the following supplemental information should accompany any submitted analytical data, as applicable: • Chemicals and dosages added to the treatment system, including location ofinjection points (see Attachment 2 (Supplemental Data workbook, tab titled "Chemical Dosages"); • Laboratory reports associated with the sampling data; and • Identification ofwhether any data or supplemental information submitted to EPA is considered confidential business information.Enclosure 3 Legal Authority This request for information is made under authority provided by Section 308 of the Federa l Water Pollution Control Act , as amended , 33 U.S.C. 1318 . Section 308 provides , in part , that , "Whenever required to carry out the objecti v e ofthis Act , including but not limited to . .. developing or assis t ing in the deve lopm ent of any effluent limitation, or other limitation, prohibition, or effluent standard, pretreatment standard, or standard of performance under this Act . . . the Administrator shall require the owner or operator of any point source to (i) establish and maintain such records , ( ii) make such reports , (iii) i nstall , use, and maintain such monitoring equipmen t or methods ... , ( iv) sample such effluents ... , and (v) provide such other information as [she] may reasonably require." Confidentiality A business ("you" ) may not withhold information from EPA on the grounds that i t is confidential. You may, however, if you desire, assert a business confiden tiality claim covering part or all of the information that you furnish to EPA. EPA regulations concerning confidential business information are contained in 40 CFR Part 2 , Subpart B. The manner of asserting such a claim is specified in 40 CFR 2.203(b). Information covered by such a claim will be disclosed by EPA only to the extent , and b y means o f the proce9ures , set forth in Subpart B. If you wish to claim as confidential any of the information covered by the enclosed request, you must do so at the time you submit the information to EPA. If no such claim accompanies the information when EPA receives it, EPA may make the information available to the public without further notice to you . E PA will notify you in the event that a request is made for release of information that you have claimed to be confident ial or EPA otherwise decides to make a determination as to whether or not such information is entitled to confidential treatment. At that time , EPA will request that you substantiate any claim you have made that information is confidential. Therefore , we encourage you to consult 40 CFR Part 2 , and to claim as confidential only those items that you truly believe satisfy the criteria for confidentiality.

Note that effluent data are not eligible for confidential treatment (see 40 CFR 2.302 ) .Enclosure 4 Notice ofIntent to Transfer Confidential Information to Selected EPA Contractors EPA intends to grant access to any confidential information collected aspart ofthe steam electric effluent guidelines rulemaking to selected EPA contractors. In accordance with 40 CFR Sect ions 2.301(h)(2

-3), 2.302(h)(2-3), and 2.305(h)(2-3), EPAmay allow those contractors identified belowaccess to all data (including data claimed to be confidentia l) collected as part ofthis data request. Transfer ofthis information to these contractors is necessary in order for the contractors to assist EPA in performing technical, statistical, and environmental analyses to support the development ofeftluent limitations guidelines and standards for the Steam Electric Power Generating industry. The contractors and subcontractors that willbeproviding support to EPAduring the development ofthese regulations are listed below: EPA Office EPA Contract

Receiving Contractor Name No. Type ofSupport

Support Office ofWater/ Eastern Research Group, Inc. EP-C-12-021 Engineering analysis Office of Science & Technology/ Engineering & Westat EP-C- 1 0

-023 Statistical analysis Analysis Division EPAhas determined that it is necessary to transfer the information described above tothe designated contractors and subcontractors in order that they may carry out the work required by their contracts. The contracts contain all provisions necessary to implement the confidentiality regulations (see 40 CFR2.301(h)(2), 2.302(h)(2), and 2.305(h)(2)). In accordance with these confidentiality regulations, you are entitled to provide comments to EPA regarding this notice ofcontemplated disclosure. Any such comments must bereceived by EPA in writing within 10 days ofyour receipt ofthis notice. Please send such comments to: Phillip Flanders USEPA Headquarters William Jefferson Clinton Building 1200 Pennsylvania Ave., N.W. Mail Code: 4303T Washington, DC 20460· flanders

. phillip@epa.gov