MARYLAND DEPARTMENT OF THE ENVIRONMENT WATER AND SCIENCE ADMINISTRATION NOTICE OF TENTATIVE DETERMINATION Washington County Application for State Discharge Permit 21DP2563, NPDES Permit MD0063509: The Washington County Water Quality Department has submitted a permit renewal application to discharge treated wastewater at an average of 4.50 million gallons per day (mgd) from the Conococheague Wastewater Treatment Plant (WWTP), located at 16232 Elliott Parkway, Williamsport, MD 21795, into Conococheague Creek. This creek is classified as Use IV-P waters, protected for supporting adult trout for catch-and release fishing, and designated as a public water supply. The Maryland Department of the Environment (MDE) is proposing to reissue the discharge permit with the following effluent limitations: BOD5, 18 mg/L maximum (max.) monthly average & 27 mg/L max. weekly average (5/1- 10/31), and 27 mg/L max. monthly average & 41 mg/L max. weekly average (11/1- 4/30); BOD5 Percent Removed, 85% minimum (min.) monthly average; Total Suspended Solids (TSS), 27 mg/L max. monthly average & 41 mg/L max. weekly average, and 374,604 lbs/year max. annual load; TSS Percent Removed, 85% min. monthly average; *Total Ammonia Nitrogen as N (NH3) - Interim Limits, 4.6 mg/L max. monthly average & 16.5 mg/L max. daily average (5/1- 10/31), and 10.7 mg/L max. monthly average & 19.4 mg/L max. daily average (11/1- 4/30); *NH3 - Final Limits ( in effect twelve months after the permit effective date) 2.3 mg/L max. monthly average & 8.6 mg/L max. daily average (5/1- 10/31), and 5.7 mg/L max. monthly average & 19.4 mg/L max. daily average (11/1 - 4/30); E. coli, 115 MPN/100mL max. monthly geometric mean; Total Residual Chlorine, 0.057 mg/L instantaneous max. (when chlorine-containing compounds are used for wastewater treatment); Dissolved Oxygen, 5.0 mg/L at any time; and pH, maintained between 6.5 and 8.5. Annual Load Limits for Nitrogen & Phosphorus The maximum annual loads for Total Nitrogen (TN) and Total Phosphorus (TP) are implemented in two phases, based on waste load allocations (WLAs) from the Chesapeake Bay (CB) TMDL and load transfers from a decommissioned Garden State Tanning (GST) facility and the Smithsburg WWTP. The Phase I limits combine the base WLAs from the CB TMDL with loads transferred from GST, where a max. annual load limit of 76,674 lbs/yr for TN is calculated as 49,947 lbs/yr (WLA from CB TMDL) + 26,727 lbs/yr (GST), and the proposed max. annual load limit of 3,758 lbs/yr for TP is calculated as 3,746 lbs/yr (CB TMDL) + 12 lbs/yr (GST). The Phase II limits add loads transferred from the Smithsburg WWTP to the Phase I totals, where a max. annual load limit of 83,251 lbs/yr for TN is calculated as 76,674 lbs/yr (Phase I Total) + 6,577 lbs/yr (Smithsburg WWTP), and a max. annual loading rate limit of 5,358 lbs/yr for TP is calculated as 3,758 lbs/yr (Phase I Total) + 1,600 lbs/yr (Smithsburg WWTP). All effluent limitations meet the local TMDLs for Bacteria, Nutrients, and Sediment in Conococheague Creek, and the Chesapeake Bay TMDL for Nitrogen, Phosphorus, and Sediment by USEPA on 12/29/2010. Limits are set to ensure water quality standards. Monitoring and reporting requirements for effluent and influent are mandated to ensure compliance with the permit. Per MD Environmental Article § 1–602(a)(2), an EJ score of 69.4 was calculated for this facility. This score has been calculated based on a combination of the following factors: Pollution Burden Exposure Percentile, Pollution Burden Environmental Effects Percentile, and Sensitive Population Percentile. For more information on how the score was calculated, launch the MDEnviroScreen tool from this website-https://mdewwp.page.link/EJ. Copies of the application, draft permit, and Summary Report & Fact Sheet (SRFS) are available on the Department’s Wastewater Permits Interactive Search Portal at https://mdewwp.page.link/WWPPortal. Search for “21DP2563” under “State Num” and click on the “More Info” button for the permit entry to generate a list of available documents for download. If a written request is received by November 6, 2025, a public hearing on the tentative determination for this application can be scheduled. The request should be sent to the Maryland Department of the Environment, Water and Science Administration, 1800 Washington Blvd., Baltimore, Maryland 21230-1708, Attn.: Yen-Der Cheng, Chief, Municipal Permits Division and must include the name, address and telephone number (home and work) of the person making the request, the name of any other party whom the person making the request may represent, and the name of the facility and permit number. Failure to request a hearing by November 6, 2025 will constitute a waiver of the right to a public hearing on the tentative determination for this permit. Written comments concerning the tentative determination will be considered in the preparation of a final determination if submitted to the Department, to the attention of Yen-Der Cheng at the above address, on or before November 17, 2025. Any hearing-impaired person who requests a hearing may request an interpreter at the hearing by contacting Mr. Cheng at (410) 537-3363 or 1-800-633-6101, or by written request to the above address at least ten working days prior to the scheduled hearing date. Information supporting the tentative determination, including the draft permit and fact sheet, may be reviewed by contacting Mr. Cheng at the above telephone number to make an appointment or by written request to Mr. Cheng at the above address. Copies of documents may be obtained at a cost of $0.36 per page. Oct. 17, 24, 2025 #11749891