NC0081281_Facility Update_20140204

Henson, Belinda
From: Ogallo, Letoya <[e-mail]>
Sent: Tuesday, February 04, 2014 3:49 PM
To: Henson, Belinda
Cc: Kashmer, Kimberly
Subject: Richmond County CT site
Hi Belinda,
As we discussed on the phone this morning, the Richmond County Combustion Turbine Plant (Smith Plant) had an upset
that resulted in the discharge of 'settled water' purchased from the Richmond County water treatment plant (WTP)
through outfall 003. The direct cause of the discharge seems to have been that the recirculation valve at the WTP was
closed and needed to be manually opened by County staff. By design, when the pressure in the settled water line is over
50 psi, the recirculation valve should automatically open and send water into the WTP's recirculation tank. This did not
occur. Instead, the safety release valve at Smith Plant was triggered at 55 psi and directed settled water into the 003
pond. The 003 pond filled and then discharged through the overflow culvert.
Smith Plant staff discovered the overflow when they visually inspected the 003 pond on 2/3/14. Coincidentally, plant
staff had also been routing dechlorinated cooling tower blowdown to 003 in accordance with the NPDES permit. When
staff became aware that settled water was being discharged, they contacted County staff who manually opened the
recirculation valve and reduced pressure on the settled water line.
Smith plant staff sampled the water in the 003 pond for pH and total residual chlorine (TRC). At 8 am on 2/3, lab results
showed a pH of 7.1 s.u. and a TRC value of 142 ug/L. At 9:00 am, water was released through controlled outfall 003
valve as dechlor was added to the water. A NPDES sample of the discharge water was taken with a result of pH 6.1 and
TRC of 15 ug/L. Due to the nature of the site layout, the discharge from outfall 003 would have travelled over rough
terrain, including rocks and gravel, before contacting surface water. Therefore we do not believe there would have been
an impact to the receiving stream from the discharge. Smith plant staff intends to follow-up with County personnel to
identify and correct the issue with the recirculation valve to prevent this problem from recurring in the future.
Please let me know if you have any further questions. From our conversation this morning I understand that this email
satisfies the reporting requirement necessary for this situation.
Thank you,
Toya
Toya Ogallo I Environmental Specialist
Duke Energy NPDES Permitting and Compliance
410 South Wilmington Street, Raleigh NC 27601
o: 919.546.6647 1 c: 919.608.1793 I f: 919.546.4409
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