The URL can be used to link to this page

Home My WebLink AboutNC0026662_Speculative Limits_20230131DocuSign Envelope ID: 46F350B4-58BF-45E4-A4A8-994657E88AA2 ROY COOPER Governor ELIZABETH S. BISER Secretary RICHARD E. ROGERS, JR. Director Michael King, Town Administrator Town of Princeton P.O. Box 67 Princeton, NC 27569 Dear Mr. King: NORTH CAROLINA Environmental Quality 1/31/2023 Subject: Speculative Effluent Limits Town of Princeton WWTP NPDES Permit No. NC0026662 Johnston County Neuse River Basin Draper Aden Associates submitted a speculative limits request on behalf of the Town of Princeton on October 13, 2022. The Town of Princeton is considering expanding the existing wastewater discharge to the Little River. Speculative limits were requested for flows of 0.6 MGD and 0.95 MGD. Receiving Stream. The Little River is located within the Neuse River Basin. Little River has a stream classification of WS-IV, NSW, and waters with this classification are used as sources of water supply for drinking, culinary, or food processing purposes as well as for aquatic life propagation and maintenance of biological integrity, wildlife, secondary recreation and agriculture. The USGS responded to a low flow request with the following revised flows: the Little River has a summer (annual) 7Q10 flow of 1.1 cfs, a winter 7Q10 flow of 13.2 cfs, a 30Q2 flow of 23.3 cfs, and an annual average flow of 280 cfs. The Little River at Outfall 001 [stream segment 27-57-(20.2), from Spring Branch to a point 0.6 mile downstream of Smith Mill Run] is not currently listed as an impaired waterbody on the 2022 North Carolina 303(d) Impaired Waters List. There are no specific permitting strategies or TMDLs for this section of the river. 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 0.6 MGD and 0.95 MGD WWTP are presented in Tables 1 and 2. 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 � _ DEQ� NORTH CAROLINA oeo.meei of Environmental Want- 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: 46F350B4-58BF-45E4-A4A8-994657E88AA2 there are additional pollutants with certified methods to be reported, please submit the Chemical Addendum to NPDES Application and, if applicable, list the selected certified analytical method used. TABLE 1. Speculative Limits for Town of Princeton WWTP (Proposed Expansion to 0.6 MGD) EFFLUENT CHARACTERISTICS EFFLUENT LIMITS Monthly Average Weekly Average Daily Maximum Flow 0.6 MGD BOD5, 20°C — Summer * 5.0 mg/L 7.5 mg/L BOD5, 20°C — Winter * 10.0 mg/L 15.0 mg/L NH3 as N - Summer * 1.0 mg/L 3.0 mg/L NH3 as N - Winter * 2.0 mg/L 6.0 mg/L Dissolved Oxygen (minimum) Daily average > 6.0 mg/1 TSS 30 mg/L 45 mg/L Total Residual Chlorine 28 ug/L Fecal coliform (geometric mean) 200/100 mL 400/100 mL Total Phosphorus Monitor & Report Total Nitrogen 5,561 lb/yr Chronic Toxicity Pass/Fail (Quarterly test) 46% *Summer: April 1 — October 31 * Winter: November 1 — March 31 TABLE 2. Speculative Limits for Town of Princeton WWTP (Proposed Expansion to 0.95 MGD) EFFLUENT CHARACTERISTICS EFFLUENT LIMITS Monthly Average Weekly Average Daily Maximum Flow 0.95 MGD BOD5, 20°C — Summer * 3.0 mg/L 4.5 mg/L BOD5, 20°C — Winter * 6.0 mg/L 9.0 mg/L NH3 as N - Summer * 1.0 mg/L 3.0 mg/L NH3 as N - Winter * 2.0 mg/L 6.0 mg/L Dissolved Oxygen (minimum) Daily average > 6.0 mg/L TSS 30 mg/L 45 mg/L Total Residual Chlorine 28 ug/L Fecal coliform (geometric mean) 200/100 mL 400/100 mL Total Phosphorus Monitor & Report Total Nitrogen 5,561 lb/yr Chronic Toxicity Pass/Fail (Quarterly test) 57% *Summer: April 1 — October 31 * Winter: November 1 — March 31 Some features of the speculative limit development include the following: D_E NORTH CARCLINA 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 DocuSign Envelope ID: 46F350B4-58BF-45E4-A4A8-994657E88AA2 • BOD Limits. The Division evaluates expanding discharges using a Level B model intended to assess protection of the water quality standard for dissolved oxygen. The model used by the Division predicted instream dissolved oxygen below the water quality standard of 5.0 mg/1 under both flow scenarios. Based on the results of the model the Division recommends increasing the dissolved oxygen effluent limit to a daily average greater than 6.0 mg/L. With this change, the model predicts the effluent concentrations will not cause exceedances in the dissolved oxygen instream standard for both proposed flow scenarios. In accordance with 15A NCAC 02B .0404 (c), the winter oxygen -consuming wasteload allocation shall not exceed two times the summer oxygen -consuming wasteload limitations nor shall it be less restrictive than minimum treatment requirements. • NH3 Limits. In accordance with 15A NCAC 2B.0206, the following streamflows are used for dilution considerations for development of WQBELs: 1 Q 10 streamflow (acute Aquatic Life); 7Q10 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). For municipals the Acute Ammonia limit (Weekly Average) is derived by multiplying the Chronic limit (Monthly Average limit) multiplied by 3. Using a Level B model, the summer ammonia limit was adjusted down to 1.0 mg/L to protect the water quality standard for dissolved oxygen. In accordance with 15A NCAC 02B .0404 (c), the winter oxygen -consuming wasteload allocation shall not exceed two times the summer oxygen -consuming wasteload limitations nor shall it be less restrictive than minimum treatment requirements. 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 and/or can be found online at: https://files.nc.gov/ncdeq/Surface%20Water%20Protection/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. If required, a 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://deq.nc.gov/permits- regulations/sepa/review-process and at: https://deq.nc.gov/about/divisions/water-infrastructure/documents/cdbgi- 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 Tables 1 & 2 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. D_E NORTH CARCLINA 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 DocuSign Envelope ID: 46F350B4-58BF-45E4-A4A8-994657E88AA2 Respectfully, r AAD'o''c''u..Siwwgne''d by: A `' • .� I^.' I ` ult(ntil� ►VWV�k"kLL C464531431644FE... Michael Montebello NPDES Program Branch Chief Attachment: Link to EAA Guidance Document, Chemical Addendum Form, and NPDES application information: http s : //deq.nc. gov/about/divisions/water-resources/water-quality-permitting/npdes-wastewater/npdes-permitting-process/npdes-individual- permit-applications ec: NPDES Files [Laserfiche] Town of Princeton / Michael King [m.king@myprincetonnc.com] Draper Arden Associates / Ethan Gartin, P.E. [egartin@trccompanies.com] TRC / Steven Gandy, P.E. [sgandy@trccompanies.com]; Alison McLuckie [amcluckie@trccompanies.com] DWR / Doug Dowden [doug.dowden@ncdenr.gov]; Derek Denard [derek.denard@ncdenr.gov]; Bradley Bennett [bradley.bennett@ncdenr.gov] RRO / Scott Vinson [scott.vinson@ncdenr.gov]; Vanessa Manuel [vanessa.manuel@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, Francis Oggeri [francis.oggeri@ncdenr.gov]; Nora Deamer [nora.deamer@ncdenr.gov] D_E NORTH CARCLINA 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