NC0024244_Compliance Report_20240909

Office of now Mailing Address
Public Utilities P. O. Box 190
Administration L B E L E Albemarle, C.
[phone] 28002-0190
NORTH CAROLINA
Ala e'. A;. land'
09/06/2024
Mr. Gary Perlmutter
NCDEQ, Division of Water Resources
512 North Salisbury Street
Raleigh, NC 27604
Re: City of Albemarle Wastewater Treatment Plant NPDES Permit No NC0024244.
Cadmium and Copper Compliance Schedule
Dear Mr. Perlmutter:
Please accept this letter as Albemarle's response to NPDES Permit No NC0024244, Item A. (8.)
of the permit at the top of Page 12, Schedule of Compliance for Cadmium and Copper Limits.
Albemarle has been tracking effluent concentrations of Cadmium and Copper as required by the
permit since its issuance (and as required by previous permits). In general, the City's wastewater
plant has no issue obtaining the effluent compliance limits set for Cadmium.
The Long Creek Wastewater Treatment Plant does have a challenge meeting the effluent limits
set for copper, and roughly half the months the plant would be in violation of the planned Sept
2025 limits.
Albemarle's treatment plant has experienced prolonged periods of low influent BOD, with
many months over the past 5 years the average BOD of the influent measured below 100 mg/L.
Furthermore, the aeration process uses floating aerators that are not effective at maintaining
proper mixing inside the aeration process. The result is that very little solids are developed by
the biological process, the plant has a difficult time maintaining proper MLSS concentration,
and it is suspected that what solids are developed settle in the aeration basin and cannot be

resuspended by the floating aerators. As such, most months dating back to 2018 the Long Creek
Wastewater Treatment Plant has wasted zero sludge from the aeration/clarification process.
Since the only way to remove Copper from the wastewater flow stream is by capturing the metal
in the sludge, Albemarle has had no method of effectively removing Copper.
Albemarle is currently under design of CWSRF Project No. CS370522-08 consisting of an
extensive rehabilitation effort at the facility. A key component of the project is transitioning the
aeration process from floating aerators to fine bubble diffused aeration. The project is currently
scheduled for completion in early 2028, and once the project is finished, the MLSS in the
aeration basins will remain fully mixed and the plant will regularly produce a waste sludge
product. Albemarle and our engineer for the project, LKC, are confident that after completion of
CS370522-08 the plant will either (1) comfortably meet the Copper effluent limits, or (2) the
corrective action to achieve Copper compliance will be minor and inexpensive in nature
featuring periodic chemical feed.
In recent email conversations you mentioned Albemarle has the option of conducting a Water
Effect Ratio study for Copper and the WER study could result in noticeably higher limits for
copper.
Presently, Albemarle is considering which of the two pathways is most appropriate:
1. Conduct the Water Effect Ratio study to see if higher (less stringent) Copper limits are
appropriate for the discharge location; or
2. Request a modification to the NPDES Permit, specifically changing the milestones in A.(8.)
to reflect the expected completion date of CS370522-08.
The City of Albemarle will notify you of our intentions before the end of calendar year 2024.
The City of Albemarle thanks you for the opportunity in the consideration of our request. If you
need any additional information or have any questions, please feel free to contact us. I look
forward to your response.
Sincerely,
City of Albemarle
Public Utilities Assistant Director
Collections System ORC
Phone:[phone]
CC: Brandon Plyler LCWWTP ORC/ M:704-438-5973
Jay Voyles Director od PU/ 0:704-984-9609 M: 704-438-3178