NC0087084_NOVNOI2022LV0342_RESP_20220603

Town of Forest City
(P.O. Box728
Torest City, North CaroCna 28043
June 3, 2022
Daniel Boss, Assistant Regional Supervisor
Water Quality Operations Sections
Asheville Regional Office
Division of Water Resources, NCDEQ
Dear Mr. Boss,
In response to the Notice of Violation date May 25, 2022, 1 would like to provide a brief history of the
Riverstone plant where the violation occurred. For 13 consecutive months, the Riverstone plant was in
noncompliance for toxicity failures associated with excessive zinc discharges from the former Horsehead,
now American Zinc Products (AZP), facility. When Horsehead filed for bankruptcy in 2015 and closed
temporarily, the Riverstone plant returned to full compliance.
AZP restarted operations in 2018. As a result, metals and ammonia levels have increased significantly. A
consent order was entered into in 2019 for ammonia, however the problem was not resolved by the end of
the consent order. In March 2021, an administrative order was sent to AZP. During the adjudication hearing
on May 26, 2021, both parties agreed to develop a memorandum of understanding. At this hearing, AZP
agreed to pay for sludge removal from the Riverstone plant during the negotiation period. After significant
work by both parties, an agreement was recently executed on May 27, 2022.
Throughout the negotiation period, limited wasting was done due to the high concentration of metals in the
sludge. In July 2021, we started wasting a little at a time. By December 2021 with the increased ammonia and
metals, it became evident that too much wasting had occurred. As a result, we failed TSS and Toxicity for the
month of December. We reseeded the plant at the end of December 2021. As a result, TSS increased and
fecal failed.
Sampling is required once per week at Riverstone. When sampling for fecal one week in January 2022, we
exceeded the limit. DPD powder is used to check effluent discharge for the presence of chlorine before
sampling for fecal. With the TSS issues in the prior month, the sample had small amounts of solids floating
and made it difficult to see a change in color from the DPD powder. We did not catch that it had exceeded
the limit until the week had already passed so there was not a chance to sample back into compliance for
that week. We have created a system between Supervisor, ORC, and Lab Analyst to ensure if this problem
happens again that we will be notified and immediately sample back into full compliance. After January 2022
Riverstone has been in full compliance with the permit, and we anticipate that it will stay that way.
Thanks, Jacob Hodge l6� V fib -
¢/ " 1/y,
ORC