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NC0067008_Draft Factsheet_20230530NCDEQ / DWR / NPDES EXPEDITED FACT SHEET - NPDES PERMIT RENEWAL NPDES Permit NCO067008 Catherine Shadwell, Compliance & Expedited Permitting Unit / (919)707-3613 May 2023 FACILITY INFORMATION Facility Name Old Cove Creek WWTP Applicant Name Water Quality Lab and Operations, Inc (Paul Isenhour, president) Applicant Address P.O. Box 1167 Banner Elk, NC 28604 Facility Physical Address/Mailing Address Physical — 207 Dale Adams Road Sugar Grove, NC 28679 Mailing — 247 Winklers Creek Rd, Suite B Boone, NC 28607 Permitted Flow (MGD) 0.01 MGD Type of Waste 100% Domestic, < 1 MGD Facility Class WW-1 County Watauga Permit Status Renewal Regional Office WSRO STREAM CHARACTERISTICS Receiving Stream Cove Creek Stream Classification C Stream Index 8-15 Outfall Lat. 360 15' 45" N 7Q 10 - Summer (cfs) 4.1 Outfall Long. 810 4705" W 7Q10 - Winter (cfs) 6 Drainage basin Watauga 30Q2 (cfs) 10.3 Subbasin 04-02-01 Average Flow (cfs) 48 HUC 060101030302 IWC (%) Summer: 0.38% Winter 0.26% 303(d) List Not listed. Facility Summary Watauga County Board of Commissioners operates a 100% domestic minor facility with an extended aeration wastewater treatment system. The permit was originally issued in 1987, this is a relatively small treatment plant that serves the neighboring recreation center and daycare (about 65 people). No recent reoccurring issues. The facility includes the following components... • Aeration Basin • Clarifier • Chlorination • De -chlorination • Return Sludge holding tank. Renewal Summary This renewal contains the following changes: • Removed pH footnote and moved pH standards to table in section A.(L) in order to keep formatting consistent. • Changed flow sample type from instantaneous to continuous since flow is 0.01MGD — in order to determine compliance with 15A NCAC 2B.0505 • Updated section A (2) to be in compliance with most updated language. • Updated outfall map Compliance History Most recent NOV was 2014. Fact Sheet for Permit Renewal May 2023 - NPDES Permit NCO067008 - Page 1 Comments on Draft Permit - Minor grammar and formatting edits - No significant comments on draft. Fact Sheet for Permit Renewal May 2023 - NPDES Permit NCO067008 - Page 2 IWC Calculations Facility: Old Cove Creek WWTP Permit No.: NCO067008 Prepared By: Catherine Shadwell Enter Design Flow (MGD): 0.01 Enter s7Q10 (cfs): 4.1 Enter w7Q10 (cfs): 6 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) 4.1 4.1 s7Q10 (CFS) 4.1 4.1 DESIGN FLOW (MGD) 0.01 0.2 DESIGN FLOW (MGD) 0.01 0.2 DESIGN FLOW (CFS) 0.0155 0.31 DESIGN FLOW (CFS) 0.0155 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 (%) 0.38 7.03 IWC (%) 0.38 7.0294785 Allowable Conc. (ug/1) 4514 242 Allowable Conc. (mg/1) 207.3 11.3 Ammonia (Winter) Monthly Average Limit (mg NH3-N/1) Design Permitted Design Permitted Fecal Coliform w7Q10 (CFS) 6 6 Monthly Average Limit: 200/100ml 200/100ml DESIGN FLOW (MGD) 0.01 0.2 (If DF >331; Monitor) DESIGN FLOW (CFS) 0.0155 0.31 (If DF<331; Limit) STREAM STD (MG/L) 1.8 1.8 Dilution Factor (DF) 265.52 14.23 Upstream Bkgd (mg/1) 0.22 0.22 IWC (%) 0.26 4.91 Allowable Conc. (mg/1) 613.4 32.4 *213 .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/I, 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)