NC0047597_bypass notice_20220105

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WATER MANAGEMENT
CITY OF DURHAM
January 5, 2022
Mr. Mitch Hayes
NCDENR
1628 Mail Service Center
Raleigh, North Carolina 27699-1628
SUBJECT: Notification of Bypass of Effluent Filters
South Durham WRF, NC0047597
Dear Mr. Hayes,
This letter is confirmation of the email 1 sent Monday afternoon regarding filter bypassing that
occurred on January 3 and 4, 2022. The first filter began bypassing (overflowing) at
approximately 5:00 am on January 3rd. Anywhere from one to four filters were overflowing at
times for the next 23 hours. All filter bypassing ended by 4:00 am on January 4th.
High plant flow was due to heavy rain. A total of 3.5 inches of rain was recorded at this site. The
TSS for the January 3rd composite were 7.2 mg/1. 1 estimate that 6 million gallons of plant flow
was not filtered. Blankets were maintained in the final clarifiers, so 1 do not expect that any
permitted parameters were exceeded.
The four filters are traveling bridge filters with an overflow weir that allows the filters to remain
in service when hydraulically overloaded and bypass only a portion of the flo w.
If you have any questions or need additional information, please email me or call me at 919-560-
4386, ext. 35532
Sincerely,
C
Charles Cocker
Superintendent
cc: Water Management
Vicki Westbrook
John Young