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Home My WebLink AboutNC0088366_Speculative Limits_20230104DocuSign Envelope ID: 9B55104C-997A-4859-A454-AF810268D9A6 ROY COOPER Governor ELIZABETH S. BISER Secretary RICHARD E. ROGERS, JR. Director Mr. Joseph W. McGougan, P.E. MBD Consulting Engineers, PA 1300 Second Ave., Suite 211 Conway, South Carolina 29526 Dear Mr. McGougan: NORTH CAROLINA Environmental Quality 1/4/2023 Subj ect: Speculative Effluent Limits South Harnett Regional WWTP NPDES Permit No. NC0088366 Harnett County Cape Fear River Basin This letter provides speculative effluent limits for expanding the South Harnett Regional WWTP located on the Little River with a proposed flow of 17.5 MGD. The Division received the speculative limits request in a letter dated February 8, 2022. Please recognize that speculative limits may change based on future water quality initiatives, and it is recommended that the applicant review the speculative limits with the Division's Municipal NPDES Unit when the NPDES permit application is submitted. Receiving Stream. Little River is located within the Cape Fear River Basin. Little River has a stream classification of C, and waters with this classification have a best usage for aquatic life propagation and maintenance of biological integrity, wildlife, secondary recreation and agriculture. Little River has a summer 7Q10 flow of 36 cfs, a winter 7Q10 flow of 89 cfs, a 30Q2 flow of 95 cfs, and an annual average flow of 480 cfs. Little River is not currently listed as an impaired waterbody on the 2022 North Carolina 303(d) Impaired Waters List however, the Cape Fear River downstream of the river has a history of nutrient impairments. Based upon a review of information available from the North Carolina Natural Heritage Program Online Map Viewer, there are no Federally Listed threatened or endangered aquatic species identified within a 5-mile radius of the proposed discharge location. 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 to 17.5 MGD are presented 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 upon receipt of a complete NPDES permit application. Every applicant shall also 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 LINA ueo.m.m oremrnment Want - DEQ3NORTH CARO North Carolina Department of Environmental Quality I Division of Water Resources 512 North Salisbury Street 11617 Mail Service Center I Raleigh, North Carolina 27699-1617 919.707.9000 DocuSign Envelope ID: 9B55104C-997A-4859-A454-AF810268D9A6 Chemical Addendum to NPDES Application and, if applicable, list the selected certified analytical method used. Some features of the speculative limit development include the following: • BOD/NH3/Nutrient Limits. With current modeling of the Cape Fear River Basin underway, no new models are being evaluated to develop limits for facilities in the modeled segments. Therefore, mass - loading of oxygen consuming wastes have been frozen based on current permit limits. These speculative limits can be re-evaluated once current modeling is finished. These limits are expected to require advanced treatment technologies. • Total Copper Limits. An updated Reasonable Potential Analysis (RPA) was performed for the proposed flow scenario to determine limits for Total Copper. TABLE 1. Speculative Limits for South Harnett Regional WWTP (Proposed Expansion to 17.5 MGD) EFFLUENT CHARACTERISTICS EFFLUENT LIMITS Monthly Average Weekly Average Daily Maximum Flow 17.5 MGD BOD5, 20°C 4.3 mg/L 6.4 mg/L NH3 as N - Summer * 0.84 mg/L 2.5 mg/L NH3 as N - Winter * 1.7 mg/L 5.1 mg/L Dissolved Oxygen (minimum) Daily average > 5.0 mg/1 TSS 30 mg/L 45 mg/L TRC 28 ug/L Fecal coliform (geometric mean) 200/100 mL 400/100 mL Total Copper 37.0 ug/L 50.3 ug/L Total Phosphorus Load (Apr. -Oct.) 53,543 lbs/season (summer mass loading) Total Nitrogen Load (Apr. -Oct.) 160,628 lbs/season (summer mass loading) Chronic Toxicity Pass/Fail (Quarterly test) 43% *Summer: April 1 — October 31 * Winter: November 1 — March 31 Engineering Alternatives Analysis (EAA). 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 the Division guidance for preparing EAA documents is attached. 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. If required, a FONSI must be issued prior to issuance of the NPDES permit for the expansion. DE NORTH CAROLINA gaparMeM of Environment,/quay North Carolina Department of Environmental Quality I Division of Water Resources 512 North Salisbury Street 11617 Mail Service Center I Raleigh, North Carolina 27699-1611 919.707.9000 DocuSign Envelope ID: 9B55104C-997A-4859-A454-AF810268D9A6 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 Kristin Litzenberger at (919) 707-3699 / kristin.litzenberger@ncdenr.gov or Michael Montebello at Michael.Montebello@ncdenr.gov. Respectfully, DocuSigned by: C464531431644FE... Michael Montebello NPDES Program Branch Chief Attachment: Link to EAA Guidance Document, Chemical Addendum Form, and NPDES application information: hops://deq.nc. gov/about/divisions/water-resources/water-quality-pernutting/npdes-wastewater/npdes-permitting-process/npdes- individual-permit-applications ec: NPDES Files [Laserfiche] Harnett Regional Water / Steve Ward, Director [sward@harnett.org] DWR / Doug Dowden [doug.dowden@ncdenr.gov]; Derek Denard [derek.denard@ncdenr.gov]; Diana Yitbarek [diana.yitbarek@ncdenr.gov] FRO / Stephanie Zorio [stephanie.zorio@ncdenr.gov] NC WRC / Gabriela Garrison [gabriela.garrison@ncwildlife.org] US FWS / Sarah McRae [sarah_mcrae@fws.gov]; Sara Ward [sara_ward@fws.gov] DWR Basinwide Planning / Nora Deamer [nora.deamer@ncdenr.gov] D_E NORTH CAROLINA gaparhneM of Environment,/quay North Carolina Department of Environmental Quality I Division of Water Resources 512 North Salisbury Street 11617 Mail Service Center I Raleigh, North Carolina 27699-1611 919.707.9000