NC0047384_NOI_NOV2022LV0640_Response_20220928

NC Department of
Environmental Quality
City of Greensboro Received
6 J North Carolina Water Resources Department OCT 0 3 2022
Winston-Salem
Regional Office
September 28, 2022 via email and CERTIFIED Return Receipt 7019 1640 0002 3443 8750
Mr. Lon Snider
North Carolina Department of Environmental Quality - Division of Water Resources
Winston Salem Regional Office
450 West Hanes Mill Road - Suite 300
Winston Salem, North Carolina 27105
RE: NCDEQ September 16, 2022 Notice of Violation and Intent to Assess Civil Penalty
NOV-2022-LV-0640
T. Z. Osborne POTW NCO047384
May 2022 NPDES Permit Violations
Mr. Snider,
This correspondence is in response to your NOV/NO] certified letter of September 16, 2022 which
we received on September 22, 2022. We would like to reiterate the information provided on the
May 2022 eDMR and include an update of activities and plant performance. We appreciate you
taking the information provided into consideration as enforcement goes forward for all of the
violations.
As you are aware, the City of Greensboro T. Z. Osborne POTW (TZO) experienced several
NDPES permit violations during the month of May 2022. Beginning Tuesday, May 3, 2022 the
T. Z. Osborne Water Reclamation Facility (TZO) staff started seeing an increase in the level of
total phosphorus in the treatment processes and the ability to treat biologically was lost. This
caused increases in not only phosphorus but also ammonia, CBOD, TSS and Fecal Coliform.
Over the next 24 hours, our staff was able to determine that we had a plant upset and that an
unknown chemical had affected our biological treatment process. NCDEQ staff were notified and
kept updated throughout the plant upset.
Through the efforts outlined below, our staff was able to reach out to our industries, determine
what industrial discharge most likely caused the plant upset, and work out plans and efforts to
reestablish the biological treatment process at TZO:
May 3-8, 2022 —
• Microscopic examination of activated sludge indicated plant microorganisms had been
dramatically impacted.
• IWS contacted SIUs and IUs via email at 14:17 on May 4, 2022.
• Laboratory staff sent T. Z. Osborne influent and North Buffalo influent composite samples
of May 2, 2022 through May 4, 2022 for rush analysis in an attempt to determine the
cause.

• ORC requested PCard emergency limit increase to hire local septic hauler and order
bacteria for re -seeding.
ORC began re -seeding of TZO activated sludge: reconfigured small percent of flow
directly to aeration, initiated hauled activated sludge from domestic package plants
(11,500 gallons), ordered enzymes and nitrifying bacteria from Momar.
• Hauled domestic activated sludge (11,500 gallons) and re -seeding continued.
• At this point, microorganisms were repopulating in the aeration tanks and ammonia and
phosphorus numbers were beginning to drop.
May 9-11, 2022
• Enzymes and nitrifying bacteria on -site at TZO and being introduced into aeration tank
junction box.
• ORC increased oxygen set points to 2.0 mg/I in back of aeration tanks.
• Tested reconfiguration of some aeration tanks to facilitate faster nitrification recovery
• Microscopic examination of activated sludge and waste activated sludge indicated a good
population of microorganisms, so wasting was stopped to increase biomass.
• By Wednesday May 11, 2022 phosphorus was <1.0 mg/I.
DEQ Regional Office staff was updated frequently throughout this event and received a 5-day
plant upset report, as well as updates afterward.
Causes of Violations and Remedial Actions Taken:
• When IWS contacted all of the industries on Wednesday May 4, 2022, one SIU notified
IWS of -an -accidental -discharge -of an anti=microbiai-raw-material that occurred on Monday,
May 2, 2022 during tanker unloading with potential to cause impacts on activated sludge.
- SIDS and results of their initial investigation provided.
- Lab/IWS staff evaluation found that the time line corresponded to calculated
detention times from the SIU to the TZO Plant
• IWS and laboratory staff conducted a SOUR test using our bacteria and determined that
the product released did have a significant effect on the biological activity in our plant.
• Enforcement actions against the SIU are pending in order to recoup any penalties that
may be assessed to the City by NC DEQ as a, result of these violations.
May 2022 violations
Parameter
Date
Limit
Reported
Type of
Value
Value
Violation
CBOD
5/7/2022
6.0 mg/I
26.76 mg/I
Weekly Average
Exceeded
Nitrogen,
5/7/2022
6.0 mg/I
12.36 mg/I
Weekly Average
Ammonia Total
Exceeded
Nitrogen,
5/14/2022
6.0 mg/I
11.71 mg/I
Weekly Average
Ammonia Total
Exceeded
CBOD
5/31/2022
4.0 mg/I
7.03 mg/I
Monthly Average
Exceeded
Nitrogen,
5/31/2022
2.0 mg/I
5.74 mg/I
Monthly Average
Ammonia Total
Exceeded
PO Box 3136 • Greensboro, NC 27402-3136 - www.ereensboro-nc.eov • 336-373-CITY (2489) • TTY # 333-6930

Compliance Update:
Due to the efforts of TZO staff, we were able to regain biological treatment and returned to
compliance after the May event.
We appreciate the opportunity to present this information for your consideration. If you have
any questions or need additional information, please feel free to contact me.
Sincerely,
Alicia Goots
Interim Superintendent of Laboratory and Pretreatment Services
cc: Michael Borchers, Water Resources Director (via email)
Kristine Williams, Deputy Water Resources Director (via email)
Elijah Williams, Water Reclamation Manager (via email)
Bradley Flynt, T. Z. Osborne ORC/Plant Superintendent (via email)
Amy Varinoski, Pretreatment Coordinator (via email)
Ron Boone, NCDEQ WSRO (via email)
Lon Snider, NCDEQ WSRO (via mail and email)
Jenny Graznak, NCDEQ WSRO (via email)
r
PO Box 3136 • Greensboro, NC 27402-3136 • www.greensboro-ne.gov • 336-373-CITY (2489) - TTY # 333-6930