Additional Bottom Ash Samples

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: Samples were collected at the East Bend Generating Station. The sample results are provided in the East Bend Bottom Ash spreadsheet.

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)
East Bend SPD-1 / Pond 1 2,317,392 36.5 2,965

East Bend (refer to the ICR Questionnaire, Question D3-2)
Wastestream Flow Bottom ash sluice water 188 gpm / 24 hpd / 365 dpy Boiler blowdown 1 gpm / 24 hpd / 365 dpy Coal pile runoff 105 gpm / 24 hpd / 126 dpy Filter backwash 27,000 gpd / 52 dpy Ion exchange wastewater (regeneration waste) 23 gpm / 24 hpd / 365 dpy Miscellaneous Plant usage 452 gpm / 24 hpd / 362 dpy Vacuum Filter Pump Seal Water 132 gpm / 24 hpd / 365 dpy Cooling tower overboard 990 gpm / 24 hpd / 365 dpy Landfill runoff (uncapped landfill) 119 gpm / 24 hpd / 365 dpy Sanitary 30 gpm / 24 hpd / 365 dpy General runoff 30 gpm / 24 hpd / 126 dpy Floor Drain wastewater 880 gpm / 24 hpd / 365 dpy

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

East Bend No chemicals added for ash sluicing, but bottom ash sluice water system draws from cooling tower circulating water, which is treated with de minimisconcentrations of HEDP, H2SO4, and (summer only) hypochlorite. It is likely none of these would be detectable in the bottom ash sluice water.

4. 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: The samples were collected in accordance with Method 1669. All samples collected were grab samples while bottom ash was being sluiced. The samples were collected directly from the bottom ash sluice water pipe prior to comingling with other wastewater sources. Pyrites and bottom ash are sluiced together.

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).

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)

East Bend 2 300,000 24 257

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: For East Bend, the supernatant was not collected. Instead the entire bottom ash sample was collected and sent to the laboratory for analysis.

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

East Bend Tap @ the service water intake Service water intake is on the Ohio River upstream of plant discharges

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

East Bend Intake water is screened to remove gross contaminants. Bottom ash sluice water system draws from cooling tower circulating water, which is treated with de minimis concentrations of HEDP, H2SO4, and (summer only) hypochlorite.

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

Response: Plant Plant Recycle Water

East Bend No; bottom ash sluice water system draws from cooling tower circulating water, which is process water but not
wastewater.

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

East Bend Intake sample was not analyzed for TSS; NPDESreported TSS value for the month (Aug. 2011) was 8 mg/l.

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

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

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