NC0003425_Other Correspondence_20180727

itaiN, DUKE Duke Energy
ENERGY. ENS CCP Environmental Programs
411 Fayetteville St,15th Floor
Raleigh NC 27601-1849
July 27,2018
Mr.Jeff Poupart, Section Chief
NC DWR Permitting Section
1617 Mail Service Center RECEIVED
Raleigh,NC 27699-1617 /®EN(�/®WR
Subject: Installation of Submerged Flight Conveyer AUG Q 2 2018
Roxboro Steam Station
Permit#NC0003425 Water Resources
Person County Permitting Section
Dear Mr.Poupart:
In accordance with requirements found in state and federal laws, Duke Energy is re-routing bottom ash
sluice wastewaters away from ash basins. To continue to handle these wastestreams, Roxboro Steam Station is
installing a Submerged Flight Conveyer (SFC) for the dry handling of bottom ash. This change was
communicated to your office as part of the pending NPDES permit application dated August 15, 2016. The
installation of the new SFC will be completed in September 2018. This letter is intended to provide notification of
the process startup and redirection of the wastewater prior to receipt of final NPDES permit. This is consistent
with guidance received by our staff on January 3,2018 from Sergei Chernikov.
Bottom ash from the boilers will be collected in water filled troughs for transfer to the SFC to direct the bottom ash
wastewater away from the ash basin. Overflow water from the SFC trough is captured, cooled, and recirculated.
The SFC is designed with a blowdown system for the overflow water to be discharged to the Flu-Gas
Desulfurization wastewater treatment system (FGD WWTS) as needed. Federal Effluent Limitation Guidelines
(ELGs) contain allowance to route bottom ash transport water overflows from the SFC to the FGD WWTS.
Additionally, small, incidental flows from the SFC may be sent to the ash basin or Lined Retention basin (once in
service). The FGD WWTS discharges to NPDES internal outfall 010, then to the west ash basin internal outfall
002, finally discharging to NPDES outfall 003.
In conclusion,the startup of the SFC will decrease the pollutant load and flow volumes of the ash basin discharge.
The startup of the SFC is a necessary step in the process or re-directing process wastewater flows away from the ash
basin as we proceed with activities to comply with various statutory requirements. It is our understanding from
previous discussions with your staff that no additional approvals are necessary beyond this notification.
If there are any questions about this matter,please Lori Tollie at(336)854-4916.
Sincerely,
,LB44 /o
esz
Lori Tollie
Senior Environmental Specialist
cc:Teresa Rodriguez—NC DWR 1617 Mail Service Center Raleigh,NC 27699-1617
Shannon Langley-via email
Richard Baker-via email
Julie Grzyb—NC DWR 1617 Mail Service Center Raleigh,NC 27699-1617