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16 <br /> water is estimated to be low flow or zero flow, or under certain conditions non-existent, as <br /> determined by the United States Geological Survey(USGS). Within 20 days of the date USEPA <br /> approves the draft rules submitted pursuant to this subsection, the Commission shall initiate the <br /> process for temporary and permanent rules pursuant to Chapter 150B of the General Statutes. <br /> The draft rules submitted to USEPA for approval shall include all of the following: <br /> (1) Defined terms. — <br /> a. "Treated domestic wastewater" shall mean sewage and wastewater <br /> comprised of waste and wastewater from household, commercial or <br /> light industrial operations (e.g., homes, restaurants, car washes, <br /> laundromats servicing only domestic laundry)excluding any industrial <br /> process wastewater regulated by USEPA under the Categorical <br /> Pretreatment Standards. <br /> b. "Low-risk discharges" means discharges of 2 million gallons per day <br /> or less of treated domestic wastewater when the dissolved oxygen <br /> content(DO)of the effluent is significantly higher(1.5 mg/l or greater) <br /> than the DO of the receiving water during low flow periods and the <br /> biological oxygen demand content (BOD) of the effluent is <br /> significantly lower(1.5 mg/1 or more) than the DO of the effluent. <br /> C. "Sag"means a reduction in the existing DO in the background surface <br /> receiving water to which treated wastewater will be discharged. Sag is <br /> typically related to nutrient elements within treated wastewater,which <br /> may promote the growth of oxygen-consuming micro-organisms, <br /> increasing the BOD, which at elevated levels may reduce DO in the <br /> background surface water body. <br /> (2) Criteria for permitting. — <br /> a. Applicants shall be required to demonstrate, through an analysis <br /> comparing the limits of the NPDES permit to the characteristics of the <br /> receiving water,that a proposed discharge meets criteria for a low-risk <br /> discharge as defined in this subsection. When a discharge is <br /> determined to be low-risk, the applicant shall demonstrate using <br /> simple modeling of the applicant's choosing, provided that the model <br /> chosen is utilized elsewhere in USEPA Region 4, such as the <br /> Streeter-Phelps model used in the State of Alabama, to show that the <br /> Sag, if any, in the DO of the receiving water will not exceed 0.1mg/l. <br /> b. Discharges to low flow or zero flow receiving waters shall be subject <br /> to the following conditions: <br /> 1. The receiving waters fall within any of the following <br /> categories: <br /> I. The 7Q10 or 32Q2 flow statistics are estimated to be <br /> zero by the USGS. <br /> II. The drainage area of the discharge point is less than 5 <br /> square miles as specified by the USGS on-line tools or <br /> other methodology that meets the standard of care for <br /> such work. <br /> III. The 7Q 10 flow is estimated to be less than 1 cubic foot <br /> per second by the USGS. <br /> 2. The proposed flow for any wastewater discharge shall be the <br /> lesser of the following: <br /> I. No more than one-tenth of the flow generated by the <br /> one-year, 24-hour storm event given the drainage area <br /> and calculated using the rational method. The rational <br /> Page 10 Session Law 2024-44 Senate Bill 802 <br />