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Home My WebLink AboutNC0083925_Fact Sheet_20231128NCDEQ / DWR / NPDES EXPEDITED FACT SHEET - NPDES PERMIT RENEWAL NPDES Permit NCO083925 Catherine Shadwell, Compliance & Expedited Permitting Unit / 919-707-3613 Dec 2023 FACILITY INFORMATION Applicant/Facility Name Aqua North Carolina, Inc. (Lauren Raup-Plummer) Salem Glen Subdivision WWTP Applicant Address 202 MacKenan Court Cary, NC 27511 Facility Physical Address 5075 Salem Glen Blvd Lexington, NC 27292 Permitted Flow (MGD) 0.10 MGD (0.20 MGD expansion approval) Type of Waste 100% Domestic, < 1 MGD Facility Class WW-2 County Davidson Permit Status Renewal Regional Office WSRO STREAM CHARACTERISTICS Receiving Stream Yadkin River Stream Classification WS-V Stream Segment 12-(93.5) Outfall Lat. 350 57' 57" N 7Q10 - Summer (cfs) 552 Outfall Long. 800 23' 11" W 7Q10 - Winter (cfs) 835 Drainage basin Yadkin -Pee Dee 30Q2 (cfs) — Subbasin 03-07-02 Average Flow (cfs) 1843 RUC 030401011501 IWC (%) 0.03% (summer) / 0.02% (winter) 303(d) List Not listed. BASIC INFO FOR EXPEDITED PERMIT RENEWAL Does permit need Daily Max NH3 limits? o, Nitrogen Ammonia is monitoring only due to high dilution rates in Yadkin River Does permit need TRC limits/footnote? Already present in permit Does permit have toxicity testing? No Does permit have any Special Conditions? o, but needs High Rock Lake Nutrient opener since facility is upstream of the lake. Does permit have instream monitoring? No New expiration date: December 31, 2028 Facility Summary Salem Glen Subdivision WWTP is a minor facility (flow < 1 MGD) with a design capacity and permitted wastewater discharge of 0.10 MGD. The facility was originally permitted in 1994. This facility utilizes the following treatment components: • Effluent Flow control chamber with bar screen • Flow equalization tank • Two (2) 50,000 gallon aeration basins with coarse air bubbles • Two (2) rectangular clarifiers w/ air sludge wasting and return • UV Disinfection w/ backup tablet chlorination/dichlorination • Effluent clear well • Effluent pump station • Flow measuring device • Stationary generator (backup) Fact Sheet for Permit Renewal Dec 2023 - NPDES Permit NCO083925 - Page 1 Renewal Summary This renewal contains the following changes: • Added the facility grade to Section A. (1.) and A. (2.) • Updated the effluent table in Section A. (1.) with eDMR parameter codes. • Updated Section A. (4.) to reflect current federal requirements for Electronic Reporting of Discharge Monitoring Reports. • Added section A. (3.) to include nutrient reopener for High Rock Lake since facility is upstream from the lake. Compliance History Looking back since 2018 — there have been 5 violations. Most recent inspection performed Feb 2019 found violations of visible solids in UV disinfection chamber, thick layer of sludge in both clarifiers, and foam covering more than 50% of the aeration basin. Comments on Draft Permit Fact Sheet for Permit Renewal Dec 2023 - NPDES Permit NCO083925 - Page 2 IWC Calculations Facility: Salem Glen WWTP Permit No.: NC0083925 Prepared By: Catherine Shadwell Enter Design Flow (MGD): 0.1 Enter s7Q10 (cfs): 552 Enter w7Q10 (cfs): 835 0.2 <= Permitted Flow if Different from Design Total Residual Chlorine (TRC) Ammonia (Summer) Daily Maximum Limit (ug/1) Monthly Average Limit (mg NH3-N/1) Design Permitted Design Permitted s7Q10 (CFS) 552 552 s7Q10 (CFS) 552 552 DESIGN FLOW (MGD) 0.1 0.2 DESIGN FLOW (MGD) 0.1 0.2 DESIGN FLOW (CFS) 0.155 0.31 DESIGN FLOW (CFS) 0.155 0.31 STREAM STD (UG/L) 17.0 17 STREAM STD (MG/L) 1.0 1 Upstream Bkgd (ug/1) 0 0 Upstream Bkgd (mg/1) 0.22 0.22 IWC (%) 0.03 0.06 IWC (%) 0.03 0.0561279 Allowable Conc. (ug/1) 60559 30288 Allowable Conc. (mg/1) 2778.8 1389.9 Ammonia (Winter) Monthly Average Limit (mg NH3-N/1) Design Permitted Design Permitted Fecal Coliform w7Q10 (CFS) 835 835 Monthly Average Limit: Not RequiredVot Required DESIGN FLOW (MGD) 0.1 0.2 (If DF >331; Monitor) DESIGN FLOW (CFS) 0.155 0.31 (If DF<331; Limit) STREAM STD (MG/L) 1.8 1.8 Dilution Factor (DF) 3562.29 1781.65 Upstream Bkgd (mg/1) 0.22 0.22 IWC (%) 0.02 0.04 Allowable Conc. (mg/1) 8513.4 4257.6 *2B .0404 (c) Applies Total Residual Chlorine 1. Cap Daily Max limit at 28 ug/I to protect for acute toxicity Ammonia (as NH3-N) 1. If Allowable Conc > 35 mg/l, Monitor Only 2. Monthly Avg limit x 3 = Weekly Avg limit (Municipals) 3. Monthly Avg limit x 5 = Daily Max limit (Non-Munis) If the allowable ammonia concentration is > 35 mg/L, no limit shall be imposed * By Policy dischargers < 1 MGD get limits no lower than 2 & 4 due to BAT * From 2B .0404(c) - Winter Limits can be no less stringent than 2 times the summer limits Fecal Coliform 1. Monthly Avg limit x 2 = 400/100 ml = Weekly Avg limit (Municipals) = Daily Max limit (Non -Muni) IWC Calculations Facility: Salem Glen WWTP Permit No.: NC0083925 Prepared By: Catherine Shadwell Enter Design Flow (MGD): 0.2 Enter s7Q10 (cfs): 552 Enter w7Q10 (cfs): 835 0.2 <= Permitted Flow if Different from Design Total Residual Chlorine (TRC) Ammonia (Summer) Daily Maximum Limit (ug/1) Monthly Average Limit (mg NH3-N/1) Design Permitted Design Permitted s7Q10 (CFS) 552 552 s7Q10 (CFS) 552 552 DESIGN FLOW (MGD) 0.2 0.2 DESIGN FLOW (MGD) 0.2 0.2 DESIGN FLOW (CFS) 0.31 0.31 DESIGN FLOW (CFS) 0.31 0.31 STREAM STD (UG/L) 17.0 17 STREAM STD (MG/L) 1.0 1 Upstream Bkgd (ug/1) 0 0 Upstream Bkgd (mg/1) 0.22 0.22 IWC (%) 0.06 0.06 IWC (%) 0.06 0.0561279 Allowable Conc. (ug/1) 30288 30288 Allowable Conc. (mg/1) 1389.9 1389.9 Ammonia (Winter) Monthly Average Limit (mg NH3-N/1) Design Permitted Design Permitted Fecal Coliform w7Q10 (CFS) 835 835 Monthly Average Limit: Not RequiredVot Required DESIGN FLOW (MGD) 0.2 0.2 (If DF >331; Monitor) DESIGN FLOW (CFS) 0.31 0.31 (If DF<331; Limit) STREAM STD (MG/L) 1.8 1.8 Dilution Factor (DF) 1781.65 1781.65 Upstream Bkgd (mg/1) 0.22 0.22 IWC (%) 0.04 0.04 Allowable Conc. (mg/1) 4257.6 4257.6 *2B .0404 (c) Applies Total Residual Chlorine 1. Cap Daily Max limit at 28 ug/I to protect for acute toxicity Ammonia (as NH3-N) 1. If Allowable Conc > 35 mg/l, Monitor Only 2. Monthly Avg limit x 3 = Weekly Avg limit (Municipals) 3. Monthly Avg limit x 5 = Daily Max limit (Non-Munis) If the allowable ammonia concentration is > 35 mg/L, no limit shall be imposed * By Policy dischargers < 1 MGD get limits no lower than 2 & 4 due to BAT * From 2B .0404(c) - Winter Limits can be no less stringent than 2 times the summer limits Fecal Coliform 1. Monthly Avg limit x 2 = 400/100 ml = Weekly Avg limit (Municipals) = Daily Max limit (Non -Muni)