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Home My WebLink AboutNC0089877_Fact Sheet_20240723NCDEQ / DWR / NPDES EXPEDITED FACT SHEET - NPDES PERMIT RENEWAL NPDES Permit NCO089877 Sara Bassett / Compliance & Expedited Permitting Unit / sara.bassettgdeq.nc.gov / July 2024 FACILITY INFORMATION Applicant/Facility Name Onslow Water and Sewer Authority (ONWASA) Webb Creek WWTP Contact Seth Brown Mailing Address 228 Georgetown Rd Jacksonville, NC 28540 Facility Physical Address 250 Zachary Lane Hubert, NC 28539 Permitted Flow (MGD) 0.35 MGD As -Built Flow (MGD) 0.35 MGD Type of Waste 100% Domestic, < 1 MGD Facility Class WW-3 County Onslow Permit Status Renewal Regional Office Wilmington STREAM CHARACTERISTICS Receiving Stream Wallace Creek Stream Classification SB;NSW Stream Segment 19-20 Outfall Lat. 34.706904 N 7Q 10 - Summer (cfs) 0 Outfall Long. 77.274347 W 7Q 10 - Winter (cfs) 0 Drainage basin White Oak 30Q2 (cfs) 0 Subbasin 03-05-02 Average Flow (cfs) 0 HUC 0302030202 IWC (%) 100% 303(d) List No BASIC INFO FOR EXPEDITED PERMIT RENEWAL Already has, however, the Waste Load Allocation spreadsheet for this discharge calculated NH3-N limits of 1.0 mg/L for summer and 1.8 mg/L for winter. However, Division policy has established that for small Does permit need Daily Max NH3 limits? discharges (< 1 MGD) the best available treatment technology for these facilities leads to monthly average limits no lower than 2 mg/L -summer and 4 mg/L — winter. The daily maximums for these parameters have been updated to 5 times the Monthly Average. Does permit need TRC limits/footnote? No Does permit have toxicity testing? No Does permit have any Special Conditions? Yes A. (2.) — A. (6.) Does permit have instream monitoring? Yes (D.O. pH and temperature) New expiration date: July 31, 2029 1. FACILITY SUMMARY The Onslow Water and Sewer Authority sends 100% domestic discharge to Webb Creek WWTP. Web Creek WWTP is a minor facility (flow < 1 MGD) with a design capacity and permitted wastewater discharge of 0.35 MGD facility that includes the following components: ♦ Two (2) 1.87 MGD Rotary Drum Screen System with containment ♦ One (1) 39,300-gallon Equalization Basin (Pre -Anoxic) ♦ Two (2) 38,350-gallon Pre -Aeration Basins with air diffusers ♦ One (1) 32,800-gallon Post -Anoxic Basin with mixer ♦ Two (2) 20,750-gallon MBR Basins with eight (8) 0.04-micron membrane cassettes ♦ Five (5) Blowers (2 pre -aeration, 3 membrane) ♦ One (1) 38,350-gallon Aerobic Digester with air diffusers ♦ One (1) Effluent Wash Water Wet Well with two (2) 128 GPM submersible Wash Water Pumps ♦ One (1) Effluent Composite Sampler ♦ One (1) Effluent Lift Station Wet Well with two (2) 1,100 GPM submersible Effluent Pumps ♦ One (1) 55-gallon Peracetic Acid Tank with containment and dual 280 GPH metering pump system ♦ One (1) 55-gallon drum Alum feed system with dual 1.8 GPH metering pumps ♦ One (1) 55-gallon Micro-C feed system with dual 20 GPH metering pumps RENEWAL SUMMARY This renewal contains the following changes: • Updated Section A. (7.) to reflect current federal requirements for Electronic Reporting of Discharge Monitoring Reports. • Monitoring for the parameters of Total Kjeldahl Nitrogen and Nitrate plus Nitrite Nitrogen have been added to Section A. (1.). • The Waste Load Allocation spreadsheet for this discharge calculated NH3-N limits of 1.0 mg/L for summer and 1.8 mg/L for winter. However, Division policy has established that for small discharges (< 1 MGD) the best available treatment technology for these facilities leads to monthly average limits no lower than 2 mg/L - summer and 4 mg/L — winter. The daily maximums for these parameters have been updated to 5 times the Monthly Average. • Section A. (5.) status has been updated to active following the submittal of the required Engineer's Certificate. The allocation table has been updated to include the estuary TN allocation. COMPLIANCE HISTORY Five limit violations in last permit cycle; no enforcements. COMMENTS ON DRAFT PERMIT The addition of Peracetic Acid Residual monitoring was discussed, however, the parameter was not added because of the long distance to the outfall (— 6 miles) and the short half life of PAA residuals.