NC0056863_Response to NC NOV-2021-TX-0047_20211012

To OF ' RoSE HILL
How,,i!I Ofi'
October 12, 2021
Cindy Moore,
Aquatic Toxicology Branch Supervisor
Division of water Resources, NCDEQ
1621 Mail Service Center
Raleigh, NC 27699-1621
REF: Notice of Violation: NC NOV-2021-TX-0047
Whole Effluent Toxicity (WET) Testing
NPDES Permit No. NCO056863/001
Rose Hill WWTP
Duplin County
Dear Ms. Moore:
I am responding to your 14 SEP 2021 letter, received on 20 SEP 2021 with respect to the above-referenced
subject. Our Chief WWT Plant Operator has already been in conversation about this matter with Mr. Zach
Thomas of your staff. He is aware of the resampling and a copy of the lab results have already been
forwarded to him.
Per our Chief WWT Plant Operator, the Toxicity sampling failed on July 20, 2021 due to a chlorine residual
of 0.69mg/L because of a middle-of-the-night storm event with flow in excess of 680gpm at the time of
sampling. On 7/19/21-7/20/21 there was a total of2.88"of rain fall.The Chlorination system is automatically
based on flow. Although 0.69mg/L isn't a substantial amount it was unfortunately enough to kill off the bugs
that were being tested for.
This problem was discussed with Mike Reed at Meritech Labs during the time of the July sampling . We
resampled (which is a standard procedure if a toxicity is failed for any reason) for August & September.
These resampled tests have passed without issue.
Rainfall has impacted the toxicity testing, particularly when it falls during odd time frames when the Operator
is not available to manually adjust the chlorine feed. We are in the process now of pulling toxicity samples
this week which are actually a special, 2nd species testing required for permit renewal and it's going to rain
again.
We hope this answers issues. It is rare that this has occurred, but we continue to sample and test and strive
to maintain compliance.
ResLu
lly,
J n Bauer
Cc: Zach Thomas, (via email: [e-mail])
Carl Wheeler, ORC (via email: [e-mail])
Morella Sanchez-King, WIRO (via email: [e-mail])
103 SE Railroad Street, P.O. Box 8, Rose Hill, N.C. 28458
Telephone [phone]-Fax [phone]
Email:rosehill(a)embargmail.com
www.townofrosehilinc.com