WA ST Dept of Ecology 2/15/2022 - Laserfiche WebLink

E. NUTRIENT REDUCTION EVALUATION 1. Permittees in Table 8, except for those who meet the exclusions listed in this paragraph, must prepare and submit an approvable Nutrient Reduction Evaluation (NRE) to Ecology for review by December 31, 2025. Permittees with multiple plants may submit a combined report. This combined report must include an evaluation for all plants owned and operated by the jurisdiction. Permittees that maintain an annual TIN average of< 10 mg/L and meet their action level throughout the permit term must submit a truncated NRE that satisfies S5.E.3-S5.E.5. Permittees that meet their action level throughout the permit term, maintain an annual average of< 10 mg/L TIN and a seasonal average of< 3 mg/L do not have to submit the NRE. 2. The NRE must include an all known, available and reasonable treatment (AKART) analysis for purposes of evaluating reasonable treatment alternatives capable of reducing total inorganic nitrogen (TIN). It must present an alternative representing the greatest TIN reduction that is reasonably feasible on an annual basis. 3. In addition, the NRE must assess other site- specific main stream treatment plant upgrades, the applicability of side stream treatment opportunities, alternative effluent management options (e.g., disposal to ground, reclaimed water beneficial uses), the viability of satellite treatment, and other nutrient reduction opportunities that could achieve a final effluent concentration of 3 mg/L TIN (or equivalent load reduction) on seasonal average (April —October) basis. 4. The analysis must be sufficiently complete that an engineering report may be developed for the preferred AKART alternative as well as the preferred alternatives to reach 3 mg/L TIN seasonally, without substantial alterations of concept or basic considerations. The final report must contain appropriate requirements as described in the following guidance (or most recent version): a. The Criteria for Sewage Works Design (ECY Publication No. 98-37, 2019)6 b. Reclaimed Water Facilities Manual:The Purple Book (ECY Publication No. 15- 10-024, 2019)7 5. The analysis conducted for the NRE must include the following elements: a. Wastewater Characterization i. Current flowrates and growth trends within the sewer service area. ii. Current influent and effluent quality. b. Treatment Technology Analysis 6 https://apps.ecology.wa.gov/publications/summarypages/9837.html https://apps.ecology.wa.gov/publications/SummaryPages/1510024.html Puget Sound Nutrient General Permit Page 24