NC0074268_Email_20200131

Strickland, Bev
From: Graves, Kevin <[e-mail]>
Sent: Friday, January 31, 2020 10:53 AM
To: Tuvia, Ori A
Cc: Scheringer, Stephanie; Shellenbarger, David; Brothers, Mourice; Alexander, Mike
Subject: [External] Follow up to Foaming at Crowders Creek WWTP
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Ori,
Per our phone conversation on 1/29/20, this email is a follow up to the foaming experienced at Crowders Creek WWTP
on 1/25/20.
The foam was first observed in the static aerator and effluent channel at Crowders on 1/25/20. The foaming was
abnormal for the facility so staff immediately checked all other areas of the facility. Staff collected samples from all areas
to visually inspect but could not find any abnormal conditions or foaming elsewhere in the facility. Staff checked all pHs,
DOs, and results from the online nutrient analyzer and plant performance did not appear to be impacted. The
microscope evaluation of the mixed liquor did not indicate any toxicity or shock to the plant's biology occurred. Sewer
lines were checked at this time, but all appeared to be normal. Surfactant samples were collected at the Influent and
Polishing Pond on 1/25/20, with results still pending from a contract laboratory.
Pretreatment started making contact with industrial users on 1/25/20 as well. Through their contacts, no source of an
irregular discharge was determined.
At this time, the source of the foaming is undetermined. Staff believe the foaming was due to a slug load that may have
entered the plant. The plant has not shown any adverse side effects from this foaming. Foaming improved quickly over
the next few days, and the static aerator and effluent channel have returned to normal since.
Please let me know if there are any questions or concerns.
Thanks,
Kevin Graves
Asst. Division Manager —Operations
Wastewater Treatment
City of Gastonia / Two Rivers Utilities
704-214-9147
kevin2(@tworiversutilities.com