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Home My WebLink AboutNC0070289_Fact Sheet_20231024NCDEQ / DWR / NPDES EXPEDITED FACT SHEET - NPDES PERMIT RENEWAL NPDES Permit NCO070289 Catherine Shadwell, Compliance & Expedited Permitting Unit / 919-707-3613 Oct 2023 FACILITY INFORMATION Applicant/Facility Name Stones Throw Homeowners Association (Jennifer Eggerichs) Ridgewood Farms at Stones Throw WWTP Applicant Address PO Box 690725 Charlotte NC 28227 Facility Physical Address/Mailing Address 863 Olde Creek Trail Concord NC 28025 Permitted Flow (MGD) 0.05 MGD Type of Waste 100% Domestic, < 1 MGD Facility Class WW-2 County Cabarrus Permit Status Renewal Regional Office MRO Receiving Stream STREAM CHARACTERISTICS Caldwell Creek Stream C Classification Stream Segment 13-17-8-5 Outfall Lat. 350 17' 16" N 7Q10 - Summer (cfs) 0.72 Outfall Long. 80" 35' 07" W 7Q10 - Winter (cfs) 1.5 Drainage basin Yadkin -Pee Dee 30Q2 (cfs) — Subbasin 03-07-11 Average Flow (cfs) 8.3 HUC 030401050302 IWC (%) 9.72% (summer) / 4.91 % (winter) 303(d) List Yes BASIC INFO FOR EXPEDITED PERMIT RENEWAL Does permit need Daily Max NH3 limits? Already present in permit Does permit need TRC limits/footnote? Already present in permit Does permit have toxicity testing? No Does permit have any Special Conditions? ngineering assessment requirement (MRO still has =ott received one Does permit have instream monitoring? Yes, U&D for Dissolved Oxygen and Temp ew expiration date: ovember 30, 2028 Facility Summary Stones Throw Homeowners Association runs their neighborhood Wastewater Treatment Plant. Ridgewood Farms at Stones Throw WWTP is a small, private, 100% domestic system that feeds into Caldwell Creek. The NPDES permit was originally issued in 1987. This facility utilizes the following treatment components: • Duplex Influent pump station • Bar screen • Aerobic sludge holding/thickening tank • Extended aeration • Clarifier • Tablet chlorination with contact basin • Tablet dichlorination with contact basin • Post aeration Fact Sheet for Permit Renewal Oct 2023 - NPDES Permit NCO070289 - Page 1 Renewal Summary This renewal contains the following changes: • Updated the effluent table in Section A. (1.) and A. (2.) with updated eDMR parameter codes. • Updated Section A. (4) to reflect current federal requirements for Electronic Reporting of Discharge Monitoring Reports. • Updated deadline for the Engineering Assessment in Section A. (3). Compliance History 25 NOVs since 2018, 5 enforcements since 2018 — 3 of which unpaid. According to most recent inspection report, facility is in poor shape and poorly maintained. Facility has not yet turned in their engineering assessment as required by 2020. Comments on Draft Permit Fact Sheet for Permit Renewal Oct 2023 - NPDES Permit NCO070289 - Page 2 IWC Calculations Facility: Ridgewood Farms at Stones Throw WWTP Permit No.: NCO070289 Prepared By: Catherine Shadwell Enter Design Flow (MGD): 0.05 0.2 <= Permitted Flow if Different from Design Enter s7Q10 (cfs): 0.72 Enter w7Q10 (cfs): 1.5 Total Residual Chlorine (TRC) Ammonia (Summer) Daily Maximum Limit (ug/1) Monthly Average Limit (mg NH3-N/1) Design Permitted Design Permitted s7Q10 (CFS) 0.72 0.72 s7Q10 (CFS) 0.72 0.72 DESIGN FLOW (MGD) 0.05 0.2 DESIGN FLOW (MGD) 0.05 0.2 DESIGN FLOW (CFS) 0.0775 0.31 DESIGN FLOW (CFS) 0.0775 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 (%) 9.72 30.10 IWC (%) 9.72 30.097087 Allowable Conc. (ug/1) 175 56 Allowable Conc. (mg/1) 8.2 2.8 Ammonia (Winter) Monthly Average Limit (mg NH3-N/1) Design Permitted Design Permitted Fecal Coliform w7Q10 (CFS) 1.5 1.5 Monthly Average Limit: 200/100ml 200/100ml DESIGN FLOW (MGD) 0.05 0.2 (If DF >331; Monitor) DESIGN FLOW (CFS) 0.0775 0.31 (If DF<331; Limit) STREAM STD (MG/L) 1.8 1.8 Dilution Factor (DF) 10.29 3.32 Upstream Bkgd (mg/1) 0.22 0.22 IWC (%) 4.91 17.13 Allowable Conc. (mg/1) 32.4 9.4 *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) IWC Calculations Facility: Ridgewood Farms at Stones Throw WWTP Permit No.: NCO070289 Prepared By: Catherine Shadwell Enter Design Flow (MGD): 0.09 0.2 <= Permitted Flow if Different from Design Enter s7Q10 (cfs): 0.72 Enter w7Q10 (cfs): 1.5 Total Residual Chlorine (TRC) Ammonia (Summer) Daily Maximum Limit (ug/1) Monthly Average Limit (mg NH3-N/1) Design Permitted Design Permitted s7Q10 (CFS) 0.72 0.72 s7Q10 (CFS) 0.72 0.72 DESIGN FLOW (MGD) 0.09 0.2 DESIGN FLOW (MGD) 0.09 0.2 DESIGN FLOW (CFS) 0.1395 0.31 DESIGN FLOW (CFS) 0.1395 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 (%) 16.23 30.10 IWC (%) 16.23 30.097087 Allowable Conc. (ug/1) 105 56 Allowable Conc. (mg/1) 5.0 2.8 Ammonia (Winter) Monthly Average Limit (mg NH3-N/1) Design Permitted Design Permitted Fecal Coliform w7Q10 (CFS) 1.5 1.5 Monthly Average Limit: 200/100ml 200/100ml DESIGN FLOW (MGD) 0.09 0.2 (If DF >331; Monitor) DESIGN FLOW (CFS) 0.1395 0.31 (If DF<331; Limit) STREAM STD (MG/L) 1.8 1.8 Dilution Factor (DF) 6.16 3.32 Upstream Bkgd (mg/1) 0.22 0.22 IWC (%) 8.51 17.13 Allowable Conc. (mg/1) 18.8 9.4 *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) NORTH CAROLINA 2022 303(D) LIST Rocky Yadkin -Pee Dee River Basin AU Name AU ID Description McKee Creek 2424 From source to Reedy Creek PARAMETER IR CATEGORY IBenthos (Nar, AL, FW) 5 AU Number Classification 13-17-8-4 C AU_LengthArea AU —Units 6.9 FW Miles CRITERIA STATUS REASON FOR RATING 303D YEAR ] fxceeding Criteria Fair, Poor or Severe Bioclassification 1998 Caldwell Creek 13-17-8-5a C 6.0 FW Miles 2426 From source to Freeman Drive PARAMETER IR CATEGORY CRITERIA STATUS REASON FOR RATING 303D YEAR Benthos (Nar, AL, FW) 5 Exceeding Criteria Fair, Poor or Severe Bioclassification 2008 Reedy Creek 13379 From source to McKee Creek PARAMETER IR CATEGORY Benthos (Nar, AL, FW) 5 Reedy Creek 13452 From McKee Creek to Rocky River PARAMETER IR CATEGORY Benthos (Nar, AL, FW) 5 13-17-8a C 8.1 FW Miles CRITERIA STATUS REASON FOR RATING 303D YEAR Exceeding Criteria Fair, Poor or Severe Bioclassification 2008 13-17-8b C 7.1 FW Miles CRITERIA STATUS REASON FOR RATING 303D YEAR Exceeding Criteria Fair, Poor or Severe Bioclassification 20081 Unnamed Tributary to Cold Water Creek (Lake 13-17-9-4-2-( WS-IV;CA 12.1 FW Acres Concord) 13888 Northwest Arm of Lake Concord PARAMETER IR CATEGORY CRITERIA STATUS IF= REASON FOR RATING 303D YEAR Chlorophyll a (40 µg/I, AL, NC) 115 Exceeding Criteria 2018 Rocky River 13-17a C 34.1 FW Miles 2216 From source to mouth of Reedy Creek PARAMETER IR CATEGORY CRITERIA STATUS Turbidity (50 NTU, AL, FW miles) 5 Exceeding Criteria Benthos (Nar, AL, FW) 5 Exceeding Criteria REASON FOR RATING 303D YEAR 2020 Fair, Poor or Severe Bioclassification 1998 Rocky River 13-17b1 C 9.2 FW Miles 13483 From Clarke Creek to Mallard Creek PARAMETER IR CATEGORY CRITERIA STATUS REASON FOR RATING 303D YEAR Turbidity (50 NTU, AL, FW miles) 5 Exceeding Criteria 2016 Benthos (Nar, AL, FW) 5 Exceeding Criteria Fair, Poor or Severe Bioclassification 2008 6/7/2022 NC 2022 303d List- Approved by EPA 4/30/2022 Page 190 of 192