NCG500582_Approval_20190920

ROY COOPER
CAW
MICHAEL S. REGAN
S__VWy
UNDA CULPEPPER
Wrecror
To: Scott A. McMillan
NORTH OAROLWA
EnvlronmemdQua ty
September 20, 2019
Project Manager; Environmental Affairs
Southern Power Company
3535 Colonnade Parkway
Birmingham, AL 35243
From: Hannah Headrick W
Aquatic Toxicity Branch
Subject: Biocide Use Review
Southern Power Company — Plant Rowan County Power Station
NPDES # NCG500582
Rowan County
Southern Power Company — Plant Rowan County Power Station has requested approval of the
following chemical, Gengard 7004. These products will be discharged into their Outfall 002 and
into Second Creek.
Calculations predict the use of these products, at the stated dosage rates, will not cause toxic
impacts to aquatic life in the receiving stream, Second Creek. Therefore, the use of this product
as an additive to their cooling tower blowdown, non -contact cooling water, and occasional
draining from other operational systems at Southern Power Company — Plant Rowan County
Power Station is acceptable.
cc: Julie Grzyb — Complex Permitting Branch
Roberto Scheller - MRO
North Carolina Department of Environmental Quality Division of Water Resources /Water
`L"� it Sciences Section
a ��«++`�/""', 4401 Reedy Creek Road 11621 Mail Service Center I Raleigh, North Carolina 27699-1621
919-743-8400