NC0060534_PAA Pilot Study Extension_20240409

DocuSign Envelope ID:2EB8EC9E-039B-41BA-B1CD-76296FOOA6139
t,,STATE
ROY COOPER
Governor 2r
ELIZABETH S.BISER
Secretary
RICHARD E.ROGERS,JR. NORTH CAROLINA
Director Environmental Quality
April 9, 2024
Mr. Emory G. Owen, WWTP Superintendent/ORC
City of Brevard
3226 Wilson Road
Pisgah Forest,North Carolina 28768
Subject: Letter of Understanding - Extension
Full-Scale Peracetic Acid Pilot Study
Brevard WWTP
Transylvania County
NCO060534
Dear Mr. Owen:
A request for an extension of an ongoing full-scale pilot study utilizing Peracetic Acid(PAA) as a
disinfectant was received April 3, 2024, by the Division of Water Resources (Division). The City
of Brevard's WWTP (NC0060534)intends to utilize CedarChem's 22%Peracetic Acid(PAA)for
the study in hopes to replace the existing primary disinfectant, liquid chlorination and
dechlorination. The initial timeline for the study, as determined in the December 19, 2023 Letter
of Understanding, was from January 1, 2024 to January 31, 2024. An extension to the ongoing
study to March 31, 2024 was approved by the Division on February 14, 2024. As the City has
would like to collect additional data over multiple seasons and gain a better understanding of PAA
dosing to ensure consistent disinfection, the City has requested continuation of the full-scale pilot
study until June 30, 2024. The Division has agreed to the extension.
Given the short duration of the project (From January 1, 2024 to June 30, 2024) and the minimal
likelihood of discernible water quality impacts, the Division is providing City of Brevard the
following Understanding to Conduct:
A full-scale pilot study which feeds PAA 22% from a tote into the contact chamber and alternative
location of the distribution box before the clarifiers via a flow-paced pump located in the existing
chemical building.A dose of 4.0 mg/L(as PAA)will be used during the first week of trial.Weekly
adjustment of the PAA dose will be made as needed, based on the observed microbial indicator
counts from the previous week. During the trial period, the Site personnel and CedarChem staff
will review testing data weekly and make necessary adjustment for dosing.
This Letter of Understanding is subject to the following conditions:
1. The project shall not cause or contribute to any violation of water quality standards in the
French Broad River, which is classified B waters in the French Broad River Basin. The
NPDES permit terms and conditions shall be complied with during the pilot study at the
facility.
North Carolina Department of Environmental Quality I Division of Water Resources
512 North Salisbury Street 1 1611 Mail Service Center I Raleigh,North Carolina 27699-1611
NOHIH�AHU�INA _
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DocuSign Envelope ID:2EB8EC9E-039B-41 BA-B1 CD-76296FOOA6B9
2. The facility shall keep sodium hydroxide and calcium thiosulfate onsite during the duration
of the full-scale pilot study as a backup and notify the Division if returns to dosing existing
disinfection chemicals for any reason.
3. Monitoring and Reporting.
a. No later than 2 days prior to initiating the pilot study and 2 days following the completion
of the pilot study, the City of Brevard shall notify the Asheville Regional Office and the
NPDES Municipal Permitting Unit.
b. Collect daily effluent water samples at the current effluent sampling point and
monitor parameters including Total Fecal Coliform, Escherichia coli, PAA
residual, BOD, TSS,pH, temperature and DO.
c. Report the monitoring results mentioned in Condition 3.b weekly to the Division
by email to michael.montebello(ancdenr.gov. Final summary reports for the PAA
pilot study shall be made in writing and sent to:
NCDEQ/DWR NPDES
Municipal Permitting Unit
Attn: Michael Montebello
1617 Mail Service Center
Raleigh,NC 27699-1617
and by email to: michael.montebellogncdenr.gov
d. The City shall report to the Asheville Regional Office any noncompliance that
potentially threatens public health or the environment. Any information shall be
provided orally within 24 hours from the time the City becomes aware of the
circumstances. A written report shall also be provided within five days of the time
the City becomes aware of the circumstances. Occurrences outside normal business
hours may also be reported to the Division's Emergency Response personnel at
[phone] or(919) 733-3300.
4. The City shall make available upon the Division's request any monitoring results or other
information necessary to ensure compliance with this letter of approval.
The Division may modify this Letter of Understanding upon the written request of the City. The
Division also reserves the right to modify or withdraw this Letter of Understanding if the project
does not conform to the above conditions or results in unacceptable impacts to water quality. In
such case,the Division shall notify the City in writing of its findings and identify actions required
of the City.
This Letter of Understanding applies only to conducting the full-scale PAA pilot study from
January 1, 2024 to June 30, 2024. If the City elects to permanently utilize PAA to replace the
D E Q�� North Carolina Department of Environmental Quality I Division of Water Resources
cee512 North Salisbury Street 1 1611 Mail Service Center I Raleigh,North Carolina 27699-1611
919.707.9000

DocuSign Envelope ID:2EB8EC9E-039B-41BA-B1CD-76296FOOA6139
existing liquid chlorine for disinfection, the Division will consider the results of this study and the
scope of work in order to determine whether the system will require other permits.
If you have any questions concerning this letter, please contact Michael Montebello at(919) 707-
3624 or at michael.montebello(&ncdenr.2ov.
Sincerely,
Doc/uSigne'd b/y�:, -
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Michael Montebello, Branch Chief
NPDES Municipal Permitting Unit
Hardcopy: NPDES Files
Ecopy: DWR/Asheville Regional Office
City of Brevard/WWTP Assistant Superintendent/Aaron Winans
IDKQ�� North Carolina Department of Environmental Quality I Division of Water Resources
512 North Salisbury Street 1 1611 Mail Service Center I Raleigh,North Carolina 27699-1611
��� 919.707.9000