NC0026557_Speculative Limits_20230328

DocuSign Envelope ID: BDC1E434-EBAA-40F5-9lC9-592AD82B522B
STAT!
ROY COOPER Y A
Governor
ELIZABETH S.BISER
Secretary
RICHARD E.ROGERS,JR. NORTH CAROLINA
Director Environmental Quality
March 28, 2023
Regina Mathis, Town Manager
Town of Bryson City
PO Box 726
Bryson City,NC 28713-0726
Subject: Speculative Effluent Limits
NPDES Permit NCO026557
SRP-W-ARP-0150
Bryson City WWTP
Swain County
Little Tennessee River Basin
Dear Permitttee:
This letter provides speculative effluent limits for a 1.2 MGD expansion for Bryson City WWTP.
McGill Associates, P.A. requested speculative effluent limits on September 16, 2022.
Receiving Stream. The Tuckasegee River is located within the Little Tennessee River Basin. The
Tuckasegee River has a stream classification of B. The USGS responded to a low flow request from M.
Keith Webb, PE, on September 9, 2022, with the following revised flows: the Tuckasegee River has a
summer(annual) 7Q10 flow of 358 cfs, a winter 7Q10 flow of 417 cfs, a 30Q2 flow of 417 cfs, and an
annual average flow of 1,555 cfs.
The Tuckasegee River at Outfall 001 [stream segment 2-79-(40.9)] is not currently listed as an impaired
waterbody on the 2022 North Carolina 303(d) Impaired Waters List. There are no specific permitting
strategies for French Broad River in the Little Tennessee River Basin Water Quality Plan.
Based upon a review of information available from the North Carolina Natural Heritage Program Online
Map Viewer, there are Federally Listed threatened or endangered aquatic species identified within a 5-
mile radius of the proposed discharge location (see attached). If there are any identified
threatened/endangered species, it is recommended that the applicant discuss the proposed project with
the US Fish and Wildlife Service to determine whether the proposed discharge location might impact
such species.
Speculative Effluent Limits. Based on Division review of receiving stream conditions and specific
proposed discharge location, speculative limits for the proposed expansion are provided in Table 1. A
complete evaluation of these limits and monitoring requirements for metals and other toxicants, as well
as potential instream monitoring requirements, will be addressed as part of the review of the NPDES
permit application.
North Carolina Department of Environmental Quality I Division of Water Resources
�A � 512 North Salisbury Street 1 1617 Mail Service Center I Raleigh,North Carolina 27699-1617
NORTH CtEnW
oep.mrinarEnH.anmanrsl0ual\ /� 919.707.9000

DocuSign Envelope ID:BDC1E434-EBAA-40F5-91C9-592AD82B522B
Every applicant shall submit documentation of any additional pollutants for which there are certified
methods with the permit application if their discharge is anticipated. These pollutants may be found in
40 CFR Part 136, if there are additional pollutants with certified methods to be reported,please submit
the Chemical Addendum to NPDES Application(unless this was completed earlier) and, if applicable,
list the selected certified analytical method used.
Some features of the speculative limit development include the following:
TABLE 1. Speculative Limits for Town of Bryson City Main WWTP (Proposed 1.0 MGD WWTP)
EFFLUENT EFFLUENT LIMITS
CHARACTERISTICS Monthly Weekly Daily
Average Average Maximum
Flow 1.2 MGD
BOD5,200C 30 mg/L 45 mg/L
NH3 asN M&R M&R M&R
TSS 30 mg/L 45 mg/L
TRC 28 µg/L
Fecal coliform(geometric mean) 200/100 mL 400/100 mL M&R
Total Phosphorus M&R M&R M&R
Total Nitrogen M&R M&R M&R
Mercury M&R M&R M&R
Acute Toxicity,48-hour LC-50 test, Ceriodaphnia 90%
M&R=monitor and report
• NH3 Limits. In accordance with 15A NCAC 213.0206, the following streamflows are used for
dilution considerations for development of WQBELs: 1Q10 streamflow (acute Aquatic Life);
7Q 10 streamflow (chronic Aquatic Life; non-carcinogen HH); 30Q2 streamflow (aesthetics);
annual average flow(carcinogen, HH). Limitations for ammonia are based on protection of
aquatic life utilizing an Ammonia chronic criterion of 1.0 mg/1 (summer) and 1.8 mg/1 (winter).
A Wasteload Allocation (WLA) indicated that the allowable concentration was greater than 35
mg/L. Therefore, no limit for Ammonia will be imposed.
• BOD Limits. Limitations for oxygen-consuming waste (e.g., BOD) are generally based on water
quality modeling to ensure protection of the instream dissolved oxygen (DO)water quality
standard. Secondary TBEL limits (e.g., BOD = 30 mg/1 for Municipals, 40 CFR 133 / 15A
NCAC 213 .0406) may be appropriate if deemed more stringent based on dilution and model
results. Model results indicated that Secondary TBEL limits were appropriate.
Engineering Alternatives Analysis EA& Please note that the Division cannot guarantee that an
NPDES permit for a new or expanding discharge will be issued with these speculative limits. Final
decisions can only be made after the Division receives and evaluates a formal permit application for the
expanded discharge.
In accordance with North Carolina Administrative Code 15A NCAC 2H.0105(c), the most
environmentally sound alternative should be selected from all reasonably cost-effective options.
Therefore, as a component of all NPDES permit applications for new and expanding flow includes a
detailed engineering alternatives analysis (EAA) that must be prepared. The EAA must justify the
requested design flow and provide an analysis of potential wastewater treatment alternatives. A copy of
tc�QEQ 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
NORTH GAROLINA 919.707.9000
DapYbNitl of EmbanngnGl Oual�

DocuSign Envelope ID:BDC1E434-EBAA-40F5-91C9-592AD82B522B
the Division guidance for preparing EAA documents is attached and/or can be found online at:
https:Hfiles.nc.gov/ncdeq/Surface%20Water%2OProtection/NPDES/permits/eaa-guidance-20140501-
dwr-swp-npdes_13.pdf
State Environmental Policy Act (SEPA)EA/EIS Requirements. A SEPA EA/EIS document may be
required for projects that: 1) involve $10 Million or more of state funds; or 2)will significantly and
permanently impact 10 or more acres of public lands. Please check with the DWR SEPA coordinator
(David Wainwright, 919-707-9045) as to whether your project requires SEPA review. For projects that
are subject to SEPA, the EAA requirements discussed above will need to be folded into the SEPA
document. Details related to SEPA can be found at: https:Hdeq.nc.gov/permits-rules/state-
environmental-policy-act-sepa/general-information. If required, a Finding of No Significant
Environmental Impact (FONSI)must be issued prior to issuance of the NPDES permit for the
expansion. Details related to FONSI can be found on-line at: https:Hdeq.nc.gov/permits-
regulations/sepa/review-process and at: https://deq.nc.gov/about/divisions/water-
infrastructure/documents/cdb gi-fonsiea
We understand this expansion project is moving forward rapidly; however, we would expect that
any request for NPDES permitting action for the expansion be taken within a five-year period
from the date of this letter, or the noted speculative limits in Table 1 would be subject to
reassessment and review.
Should you have any questions about these speculative limits or NPDES permitting
requirements, please feel free to contact Derek Denard at(919) 707-3618 /
[e-mail] or Doug Dowden at(919) 707-3605 /[e-mail].
Respectfully,
DocuSigned by:
E
l.lf,6.t,(, 16dtk
C464531431644FE...
Michael Montebello
NPDES Program Branch Chief
Attachment: Link to EAA Guidance Document,Chemical Addendum Form,and NPDES application information:
htWs:Hdeq.nc.gov/about/divisions/water-resources/water-quality_permitting/npdes-wastewater/npdes-permitting-
process/npdes-individual-permit-applications
cc: NPDES Files[Laserfiche]
Town of Bryson City/Regina Mathis,Town Manager[[e-mail]]
McGill Associates,P.A./M.Keith Webb,PE[[e-mail]]
DWR/WQPS Doug Dowden[[e-mail]]; Kristen Litzenberger[[e-mail]];
Derek Denard[[e-mail]];John Hennessy [e-mail]];
Charles Weaver[[e-mail]]
ARO/Landon Davidson[[e-mail]];Daniel J Boss[[e-mail]];
Tim Heim[[e-mail]]
NC WRC/Andrea Leslie[[e-mail]]
US FWS/Sarah McRae [[e-mail]]; Sara Ward[[e-mail]]
DWR Planning Section/Fred Tarver[[e-mail]];Pamela Behm[[e-mail]]
QE Q 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
NORTH GAROLINA 919.707.9000
ow.m.m m em�e�vi a�+im