40 CFR 415.282: Effluent limitations guidelines representing the degree of effluent reduction attainable by the application of the best practicable control technology currently available (BPT).

(a) Except as provided in 40 CFR 125.30 through 125.32, any existing point source subject to this subpart and using borax produced by the Trona process must achieve the following effluent limitations representing the degree of effluent reduction attainable by the application of the best practicable control technology currently available (BPT): There shall be no discharge of process wastewater pollutants to navigable waters, except that residual brine and depleted liquor may be returned to the body of water from which the process brine solution was originally withdrawn.

(b) Except as provided in 40 CFR 125.30 through 125.32, any existing point source subject to this subpart and using remined borax must achieve the following effluent limitations representing the degree of effluent reduction attainable by the application of the best practicable control technology currently available (BPT):

Subpart AB—Boric Acid Mined Borax Process

Pollutant or pollutant property BPT limitations

Maximum for any 1 day Average of daily values for 30 consecutive days

Kg/kkg (or pounds per 1,000 lb) of product

Arsenic 0.0028 0.0014

TSS 0.14 0.07

pH (1) (1)

1 Within the range 6.0 to 9.0.