Information Requested regarding the Belews Creek Steam Station and Marshall Steam Station Bottom Ash Sampling Data Provided in Comments

1

. What selection criteria did Duke Energy use to identify Belews Creek and Marshall Steam Station as plants to sample? Are there any other bottom ash data associated w i th other Duke plants? EPA requests that bottom ash sampling data be provided for all Duke Energy p l ants for which data are available.

Response: We selected Belews Creek and Marshall due to the close proximity of the stations to our in-house sampling personnel. Belews Creek and Marshall were also selected because we knew the plants would be operating and, thus, generating bottom ash sluice water. Also, we were able to determine that we could safely access the bottom ash sluice water discharge pipe.

Additional bottom ash data has been collected for the East Bend Steam Station. Responses to the questions are provided in the document “Additional Bottom Ash Data: East Bend”.

In addition, bottom ash sulfide samples were collected at Cliffside and Cayuga. These samples were provided to UWAG for analysis. Duke Energy does not have the UWAG laboratory reports, but these reports are available through UWAG. Duke En ergy did collect a split sample from Cliffside and the analytical report is included in this submission. Refer to “Cliffside Bottom Ash Lab Report 6_28_13” and “Cliffsid e EDD 6_28_13.”

Bottom ash samples were collected from Miami Fort 6 and 8 as part of testing of additives for compliance with pending air regulations. This data is being claimed Confidential Business Information (CBI) and is being provided in the folder labeled “MFS Bottom Ash”.

EPA did not specifically request responses to the questions for additional bottom ash data. Given the timeframe of the information request, responses to these questions for Cliffside or Miami Fort were not completed.

Bottom ash data from Cayuga and Gibson were collected at the request of legal counsel during fuel additive testing and is not being produced.

2 . Please provide the Pond/ Impoundment Unit ID (e.g., SPD-2) for the pond which bottom ash transport wate r sampled wou l d enter. P l ease provide the dimensions for this pond including surface area, depth, and residence time. A l so, please identify what other wastestreams flow into this impoundment and their relative contributions

.
Response: Refer to the ICR Questionnaire, Question D4-2

Station Pond Impoundment Unit ID Surface Area (ft 2 ) Depth (ft) Residence Time (hrs)
Belews Creek SPD-2 14,897,520 36.5 96 Marshall Pond 1 6,664,680 35.5 96

Belews Creek (refer to the ICR Questionnaire, Question D3-2)Wastestream Flow Bottom ash sluice water 3,520,800 gpd / 295 dpy Fly ash sluice water 230,400 gpd / 20 dpy Treated FGD wastewater 700,000 gpd / 365 dpy Landfill leachate 10,000 gpd / 365 dpy Boiler fireside cleaning water 83,000 gpd / 3 dpy Coal pile runoff 128181 gpd / 124 dpy Air heater cleaning water 664,000 gpd / 3 dpy Reverse osmosis reject water 150 gpm ; 24 hpd / 365 dpy Ion exchange wastewater 340,000 gpd / 9 dpy Floor Drain wastewater unknown

Marshall (refer to the ICR Questionnaire, Question D3-2)
Wastestream Flow Bottom ash sluice water 3,020,000 gpd / 365 dpy Fly ash sluice water 9,888,000 gpd / 2 dpy Treated FGD wastewater 1,308,000 gpd / 365 dpy Mill Reject Sluice Water 131,000 gpd / 365 dpy Boiler blowdown 2,000 gpd / 365 dpy Coal pile runoff 162,134 gpd / 129 dpy Filter backwash 7,000 gpd / 365 dpy Reverse osmosis reject water 194,000 gpd / 365 dpy Ion exchange wastewater 20,000 gpd / 56 dpy Clarifier sludge 8,000 gpd / 365 dpy Once-through cooling water 80,000 gpd / 365 dpy Limestone pile runoff 2,000 gpd / 129 dpy Gypsum pile runoff 5,000 gpd / 129 dpy Boiler fireside cleaning 77,925 gpd / 4 dpy Air heater cleaning water 326,000 gpd / 3 dpy Track hopper sump 70,000 gpd / 365 dpy Landfill runoff (FGD residue landfill) 5,000 gpd / 365 dpy Sanitary 7,000 gpd / 365 dpy Stormwater 8,330,000 gpd / 129 dpy Floor Drain wastewater unknown

3. For each plant, identify what chemicals are added to the wastestream upstream of the sample location or to the sample during settling.

Response:
Station Chemicals Added

Belews Creek No chemicals added

Marshall No chemicals added4. Please provide a more detailed description of the sampling method beyond "collected in accordance with Me thod 1669." Please specify the location of the bottom ash transport water sample provided (e.g., directly from bottom ash sluice pipe discharge into comm ingled pond or upstream prior to this point). Please specify whether the sample was a grab or composite sample. Additionally, provide duration and frequency information for all composite sampling (e .g. , 24-hour composite collected every ho ur).

Response: Refer to the document titled “UWAG Bottom Ash Sampling Protocol”.

Both samples were composite samples collected from the discharge pipe prior to comingling with other waste streams.

5. How often i s the bottom ash slu iced at the plant? Please indicate whet her samp le s were collected during periods when the bottom ash is not sluiced (i.e., sou rce water is flowing through the pipe).

Response: All samples were collected while bottom ash sluice water was being discharged.

Refer to the ICR Questionnaire, Question C3-3

Plant Unit Average Sluice Water

Flow Rate (gpd) Typical Duration

(hpd) Typical Frequency (dpy)

Belews Creek 1 880,200 6 262 Belews Creek 2 880,200 6 285 Marshall 1 1,832,400 5 267 Marshall 2 1,832,400 5 240 Marshall 3 900,000 6 336 Marshall 4 900,000 6 332

6. Please identify how long the bottom ash was in contac t with th e water pr i or to collecting the supernatant. How does this sample settling time compare to the retention time of the surface impoundment identified in question #2?

Response:

Belews Creek: The water was in contact with the bottom ash approximately 6 hours prior to collecting the supernatant. The bottom ash sample was collected in the field in the carboy and transported back to the laboratory to collect the supernatant.

Marshall: The water was in contact with the bottom ash approximately 3 hours prior to collecting the supernatant. The bottom ash sample was collected in the field in the carboy and transported back to the laboratory to collect the supernatant.7. For each plant, please provide additional details regarding the source wate r sampling locations:

a. Please specify the location of the source water samp l es provided. Please indicate whether the plant discharge is upstream or downstream of intake water location (i.e., does any of the plant's effluent contribute to intake water)?

Response: Plant Source Water Sample Location Plant Discharge

Belews Creek Tap @ the service water intake Intake water is from Belews Lake. The ash pond discharges to the Dan River downstream of Belews Lake.

Marshall Tap @ the service water intake Discharge and intake are both on Lake Norman. The discharge is to the surface water whereas; the service water intake is located at a depth of approximately 30 feet below the surface water elevation.

b. Does the plant treat the intake water prior to u se in the bottom ash sluicing system

. If so, how is the intake water treated?

Response:
Plant Bottom Ash Sluice Water Treatment

Belews Creek No treatment

Marshall No treatment

c. Does the plant recycle any process wastewater for use in the bottom ash sluicing system. If so, how?

Response: Plant Plant Recycle Water

Belews Creek No

Marshal No

8. For each plant, please provide the associated TSS concentrat ion for the source water and the bottom ash samp l es.

Response:
Plant TSS Concentration
Belews Creek Sample was not analyzed for TSS.Marshall Sample was not analyzed for TSS.

9. For each plant, describe any atypical operations occurring at the plant at the time of sampling (e.g., test burn of new coal).

Response: Plant Operations

Belews Creek Normal operation. Marshall Normal operation

10. For each plant, please provide the flow rate of the wastewater at the time of samp lin g, as well

as the average annual bottom ash discharge flow rate.

Response: See response for Question 5 above regarding the average annual bottom ash discharge flow rate.

The flow rate was not recorded at the time of sampling.