UNITED STATES ENVIRONMENTAL PROTECTION AGEN CY WASHING T O N , D

. C

. 20460

Elizabeth E

. A ld ridge Hunton & W illi ams LLP 951 East By rd St reet Richmond , VA 23219

- 4074

Dear Ms. Aldridge, 

### DEC 3 0 2 0

13 OFF ICE O F WAT E R

We rece i ved the comments you su bmitted on behal f of the U t ili ty Water Act G roup (UWAG) regard i ng EPA's proposed efflue nt li m itations guideli n es and standards (ELGs) fo r the s team e l ectric power generating point source category (78 FR 34432). We are writing to you because we have concluded that additional information is either needed or wo u ld be usef ul in evaluating your comment s with respec t to fly ash and bottom ash

. In some cases , clari fi cation is needed i n order to prope rl y interpret, validate, and evaluate the ash data submitted al ong w i th your comments. We are th erefo re aski n g that you provide the information described below i n order to ensure that the Agency appropriately considers your subm ission. As you are aware , EP A is operating with a dead l ine for ta ki ng fi nal action o n the steam elec tric E LGs. We are th u s reques t ing t hat any add itional i nfo rmation you pro v ide in response to th i s l etter be rece ived by EPA no l ater than January 24, 2014. T he f ollow i ng requests and questions pertain to data provided in Attachme n t 7 of UWAG's comments. 1. P l ease provide the p l ant name and plant location associated with each plant ID id enti fied i n Attac h men t 7

. In addition, p lease prov i de the Pond / Impo u ndmen t U nit ID (e

. g. , SPD

2) for th e sampl ed pond, as reported in the Questionn aire for the Steam E l ectric Effluent Guidelines

. 2. P lease descri be the so li ds se p aration processes and treatme n t procedures employed at each powe r p l an t fo r which data are provided. Fo r examp l e , does the p l ant use dewatering bins to separate solids from the ash transport water? Please identify if these solids separat i on processes and/or treatment procedu res are located ups tream or downs tream of the sam pl e location. For each p lan t , p lease i dentify what chemicals are added to the wastewater upstream of the sam ple l ocation. 3. From which p l an t s an d companies did UWAG request bottom ash characteri z ation data? If U WAG d id not request data from all members, w h at c ri teria were used to iden t ify the plants for wh i ch data were requested? D i d any plants p ro v ide data to UWAG that were 

### no t incl u d

ed 

### i n UWAG's 

### comme n ts to EPA? If 

### so , why were these data excluded?

I n te rn et A d dress (U R L) • h tt p :/ /www epa
. gov Recycled/Recyclable • P r i nte d wi th Vegetab l e O i l Based Inks on 100% Postco n sume r
. P r ocess C h lori n e F r ee Re c ycle d Paper4. Is the me d ian so urc e water and bottom as h s luice water concentrations provided for the dataset ca l culated u s ing all indi vi dual sampl es ( i .e., the entire dataset) or using the plant averages ? 5. For eac h pond where the data yo u s u bmi tted i s compr i se d of mu lt iple samp l e resu lts , please prov id e the po ll utant concentration data for each i nd i vidual sa mple. 6. For p lants that li st the bottom ash tran sport wate r sampling location as " BA Sluice Pipe " ( Plants 1 , 2 , 3 , 4 , 5 , 6 , 9 , 10 , 11, 18 , 1 9, 20 , & 21), please explai n why ash pond effluent concentrations were not pro v ided. 7

. Fo r each plan t , pl ease provide additi ona l details regarding the sampling locations. a. Source wate r 1. Please specify the locati o n of the source water sampl es provided (e.g., Ohio River upstream of p lant , Ohio River at poin t of intake to plant (note if intake is upstream or down s tream of p l an t dischar ges) , piping pr i o r to mixin g with bot tom ash). 11. Does the plant treat the intake water prior to u se in the bottom ash sluicin g system ? If so, how is the intake water treate d ? 111. Does the plant recycle any process wastewater for use in the bottom ash sluic in g system. If so , h ow ? b. Bottom as h tran sp ort water 1. Pl ease specify the locati on of th e bottom ash sampl e provided (e.g., for

" bottom a s h s luice pipe " please iden tify i f the sample was co ll ected immediate l y after mixing or coming out of th e pip e at the pond in fl uent)

. 11. For each ash pond , plea se ide ntify all wastestream s that e nter th e ash pond and their relative contributi o n (flow rates, pollu ta nt concentrations, and pollutant mass load s) to th e pond. 8. For eac h plant , please provide the a ssoc iated TSS co ncentrati o n for the source water (be fore and after any treatment pr ior to i t s use for transporting ash ) a nd the bottom ash sa

mples

. 9. Please provid e a more detailed de sc ription of the "sa mpling m ethod " field , as well as a description fo r eac h of the identifiers includ e d in the spread s he et (e

. g. , " multip l e grabs & composited ," "se ttl e d " )

. I n add it ion , p lease provide durat io n and frequency i nfo rm ation for composi te samp ling (e.g., 24-hour comp os ite collected every hour)

. 10. For each plant , please describe any atypical ope rations occurring at th e plant at the time of sampling (e.g. , test burn of ne w coal). 1 1. For e ach p lan t , please provide the flow rate of the w a stewat er at th e time o f sa mplin g , as well as the ave rage a nnual bottom as h discharge flo w rate. 12. Do any o f these data correspond to data included in EPRI PIS CES reports? If so , please identify which Plant ID and the correspo ndin g PISCES report. 13. A previous ver sio n of the tab l e includ e d in Attachment 7 was provid e d to the Small Business A ssociation (SBA) d uri n g intera ge ncy review of the pro po se d steam elec tric ELGs

. There, the table i ncluded a footnote " Note 1

- Multip le g rab s of bot tom ash s l uice water were samp led throughout th e slu ic ing period and composited. Then, the composite was allowed t o settle at least one ho ur prior to sampling the supernatant. " Please identify w hich , if any , plants used thi s procedure for collect ing the samples. Please provide justificat io n th at the approach describ e d in Note 1 is co mparabl e to the actual

2performance expected in the surface impo undm ents at the plants for which the samples represent. 14. In additi o n , the data prov ided in Attachment 7 dif fe rs from the data includ e d in the previous vers i on o f the table submitted to S BA ( de scribed in Question 12) fo r Plants 2 , 1 5 , and 2 1. Ple ase provide an explanation for the differences betwee n the se reported values. The fo ll owing requests and questions pe rtain to data provided in Attachment 5 of UWAG's comments. I. P lease prov ide the plant name and plant location associated with e ach plant ID identified in Attachmen t 5. In addition, please provid e the Pond ! Impoundment Unit ID (e.g., SPD2) for the sampled pond, as reported in the Questionnaire for the Steam Electric Effluent Guidelines. 2. What are the current solids separation processe s and tr eatm e nt procedures employed at each power plant for which data are provided ? Pl ease identify if these so lid s separa tion proc esses and / or treatment procedures are lo cated up stream or down stream of the sample loc ation . For each plant , please identif y what, if a ny , c he mi ca l s are added to the wastewater upstream of the sample location. 3. From which p lants/com panies did UW AG requ est sulfide c h a r acte rization data ? What c rit eria were used to identi fy the 9 plants c ho sen for sampli ng ? 4. What is the depth , volume, and residence t im e fo r the surface impoundments from which samples were co llected ? 5

. Fo r each plant , please provide further addi t ional details regarding the samplin g location s . a. Source wate r 1. Please specify the location of the source water sample s pro vi ded (e.g. , Ohio River upstream of plan t, Ohio Ri ver at point of intake to plant (note if intake is upstream or down stream of pl ant discharges), pip ing prior to mixing with bottom ash). u. Is intake water treated prior to us e in the bottom as h sluicing system? If so, please desc ribe the treatment proc ess. 111. Does the plant recycle any proces s wa s t e water for u se in the bottom ash s luicing system? If so, how? b. Bottom ash transport water 1. Please specify the location of the botto m as h sa mple provided for Plants Dl , D2 , D3 , and D4 (e.g. , ash pond n e ar effl uent). n. For ash pond effluent samples , please id en ti fy all wastest reams that enter the ash pond and their relative co ntribution (flow ra tes, pollutant concentrat i ons, and po ll utant mas s loads) to the pond. u1. Plea se identify which ash pond samp les we re collected at a depth near th e bottom of the pond and the depth at which the sample was collected. 6. For each plant , pl e a se d escribe any atypical operations occurri n g at the plant at the ti me of samp li ng (e.g., test bum of new coal). 7. Fo r eac h plant , please provide the flo w rate of the wastewate r at the time of sampling, as well as the average annual bottom as h di sc har ge flow rate. 8. Please ex plain the meaning of the asterisk(*) ne xt t o "F ield S ulfid e " in Field Test Data Table l.
3We appreciate your help 

### in providing the information described above 

### in a timely manner. If you have any questions, please do not hesi tate to call me at (202) 566-1755. Sincerely, 

# f)Jf.i- {;/
Jezebele Alicea- Vire lla

4