Section 173-221-040. Domestic wastewater facility discharge standards.

(1) Except as allowed under WAC 173-221-050, domestic wastewater facilities which discharge to surface waters shall not exceed a thirty-day average of 30 milligrams per liter (mg/L) BOD, 30 mg/L TSS. Seven-day averages shall not exceed 45 mg/L BOD, 45 mg/L TSS. Additionally, the thirty-day average percent removals of BOD and TSS shall not be less than eight-five percent of influent concentrations.

(2) Fecal coliform limits shall not exceed a monthly geometric mean of 200 organisms/100 milliliters (mL), and a weekly geometric mean of 400 organisms per 100 mL.

(3) The effluent pH value shall be between 6.0 and 9.0 standard units unless the permittee demonstrates that:

(a) Inorganic chemicals are not added to the waste stream as part of the treatment process; and

(b) Contributions from industrial sources do not cause the pH of the effluent to be less than 6.0 or greater than 9.0; and

(c) The discharge does not cause water quality violations outside of an approved dilution zone.

[Statutory Authority: RCW 90.48.035 and 90.48.260. WSR 87-23-020 (Order 87-26), § 173-221-040, filed 11/12/87.]

RCW 90.48.035 and 90.48.260. WSR 87-23-020 (Order 87-26), § 173-221-040, filed 11/12/87.

Rules

173-221-050,