NC0003425_Comments_20161012

Strickland, Bev
From:
Shell, Karrie-Jo <[e-mail]>
Sent:
Wednesday, October 12, 2016 10:15 AM
To:
Rodriguez, Teresa; Belnick, Tom
Cc:
Davis, Molly; Staples, Bridget
Subject:
Karrie-Jo's comments on Roxboro
Tom and Teresa,
Below are my comments on the Roxboro permit.
Karrie-Jo Robinson -Shell, P.E.
Environmental Engineer
US EPA Region 4
Water Protection Division
61 Forsyth Street
Atlanta, GA 30303
[phone]
From: Shell, Karrie-Jo
Sent: Friday, October 07, 2016 3:19 PM
To: Staples, Bridget <[e-mail]>; Zimmer, Andrea <[e-mail]>
Cc: Davis, Molly <[e-mail]>; Diaz, Denisse <[e-mail]>
Subject: KJ's comments on Roxboro
KJ's comments on Roxboro
EPA received the update flow schematic and other documents on September 14, 2016. Our comments are due October
14, 2016.
1. The permit application dated September 27, 2001, identified and included Form 2C data for two external outfalls
to Hyco Reservoir. An updated 2C data was submitted from Duke to NC DNR via a letter dated August 12, 2016.
Page 2 of the permit implies that 001 also has a direct discharge to Hyco Reservoir. We recommend page 2 be
modified to correctly identify outfall 001 has an internal outfall that discharge via Outfall 003 thence Hyco
Reservoir.
2. The description of the wastewater contributing to internal outfall 001 should be correctly identified on page 4.
The flow updated flow schematic indicates that internal Outfall 001 receives storm water from the east ash
basin, discharges from "areas of wetness" (AOW), discharges from seepages, and incidental gypsum and rail
runoff. Duke's letter to NC dated August 15, 2016, stated that the discharges from the AOW are from the
following seeps: S1, S2, S3, S4, S5, S6, S7, S8, S14, S18 and S19. Most, not all, of these seeps were previously
identified and sampled by Duke and are included in Duke's Topographic Map and Discharge Assessment Plan
dated April 29, 2014.
3. Please provide an explanation of how the AOW (i.e., seeps) are captured and conveyed to internal Outfall 001.
4. The permit application dated September 27, 2011, includes a Form 2C for storm water outfalls SW -A and SW-B,
which discharge to Hyco Reservoir. How are these two outfall addressed in the permit?
5. The sampling location for internal Outfall 001 should be more specific. We recommend the permit state that
sampling for internal outfall 001 be performed at the nearest accessible pint after treatment and prior to
discharging into Outfall 003.

6. The updated flow schematic shows that all emergency overflows from the FGD unit will be collected and routed
back to either the lined ash pond (once it is operational) or back to the bioreactor for treatment prior to being
discharged to Outfall 002. For clarity, we recommend the permit be revised to prohibit the discharge of
emergency overflows from the FGD unit.
7. There was no RPA submitted for outfall 006, which is comprised of coal pile runoff, limestone pile runoff,
emergency gypsum stack, truck wheel wash, storm water, and raw water tank drainage from maintenance
operations. Due to the nature of some of these discharges, we recommend NC submitted an RPA based on
more recent data than that in the September 2011 permit application. Based on information in Duke's August
15, 2016, letter to NC, the plant is already uses a dry fly ash handling system; therefore, there is no need to
allow them until November 18, 2018, to come in compliance with the new steam electric effluent guidelines for
fly ash transport.
8. In its August 15, 2016, letter to NC, Duke stated that it plans to install a vapor suppression system in 2016 at the
anhydrous ammonia tank. In the event of an emergency, this unit may release anhydrous ammonia to the
retention pond. This waste stream should be included in the description of outfall 003.
9. EPA recognizes that NC followed its mixing zone policy to establish a thermal mixing zone in the Hyco Reservoir.
Typically, waterbodies with a 7Q10 of zero cubic feet per second have no assimilative capacity. We recommend
the permit include a reopener in part A.17 that specifically states that NC will automatically reopen the permit
to include a temperature in the permit in the event that instream monitoring indicates the water quality
standard for temperature is not being met at the point of discharge.
10. The RPA for Outfall 003 indicates that one sample was taken for instream hardness and that the average
background hardness is 99 mg/L. When and where was this sample taken?
11. The RPA for Outfall 003 indicates that data between 2010-2011 was used to determine the appropriateness of
limits for chlorides, copper, nickel, selenium, thallium and strontium. Why wasn't more recent data used by NO
By contrast, data from 2011-2016 was used in the RPA for arsenic.
12. How does the RPA address changes in the ash pond effluent during both planned decanting and dewatering
operations?
13. For consistency with other permit conditions for decanting operations at other NC Duke facilities, we
recommend the following additional pollutants be added to outfall 002 during decanting and dewatering
operations: total iron, total cadmium, total chromium, total dissolved solids, and total hardness.
Karrie-Jo Robinson -Shell, P.E.
Environmental Engineer
US EPA Region 4
Water Protection Division
61 Forsyth Street
Atlanta, GA 30303
[phone]