NC0021211_NOI_NOV2024LV0659_Response_20240812

(11il f r a 4 :
P O. Drawer 357
201 South Main Street
Graham, North Carolina 27253
Tel: [phone] / Fax: [phone]
August 2, 2024
Certified Mail No. 7015 1520 0000 6467 5708
Lon T. Snider
NCDEQ\DWR
450 West Hanes Mill Rd., Suite #300
Winston-Salem, NC 27105
Dear Mr. Snider:
NC Department of
Environmental Quality
Received
Subject: Tracking No.: NOV-2024-LV-0659
Limit Exceedance Violations — May 2024
City of Graham
NPDES Permit # NCO021211
Alamance County
Winston-Salem
Regional Office
The City of Graham received a notice of violation and intent to issue civil penalty for
Limit Exceedance violations of our permit in May 2024. The City of Graham requests that you
consider the following response in your decision process prior to taking enforcement action.
In April, the shaft on one of the two surface aerators in our Extended Aeration basin
became dislodged and fell into the basin. Because of the ongoing construction from our plant
upgrade, switching to our other Extended Aeration basin was not an option nor could repairs be
made to surface aerator. A floating aerator was placed into service in the basin but as
temperatures increased during the month, it struggled to provide adequate air in the basin. In
May, we placed a pump into service to help recirculation in the basin but even that did not help
improve Ammonia results. Compounding this problem was the frequent rain received over a
three-week period during the month, averaging over 2 inches per week. Ammonia levels
continued to stay elevated throughout the month resulting in four weekly violations and
ultimately a monthly violation. And although weekly BOD results were compliant, the overall
average for the month exceeded our permit.

Regarding the daily Dissolved Oxygen violation, the city received almost 2 inches of rain
on May 15. In the 24 hours prior to sample collection, incoming plant flows averaged almost 4.4
MGD forcing the plant into a High Flow operating mode with aeration off in our Extended
Aeration basin during the majority of that time to minimize the loss of solids. Prior to May 15,
the plant had not experienced any low Dissolved Oxygen readings while down an aerator and
hasn't had any since.
On May 28, the City of Graham WWTP officially switched over to our new BNR process.
Within a few days, all parameters that had been an issue for us in recent months quickly returned
to well within compliant status. In June, all parameters, both weekly and monthly, were all
compliant with no violations. All July results received thus far have also been in compliance.
Based on the information provided herein, the City of Graham request that enforcement
action not be taken for these Limit Exceedance violations. Thank you for your consideration in
this matter. Should you have any question please contact me via email at
[e-mail] or by phone at 336-570-6721.
Sincerely,
Tonya Mann
Utilities Director
Cc: Megan Garner, City Manager
Cris Routh, Wastewater Treatment Plant Superintendent