Section 414.53 - Effluent limitations representing the degree of effluent reduction attainable by the application of the best available technology economically achievable (BAT)(a) The Agency has determined that for existing point sources whose total OCPSF production defined by § 414.11 is less than or equal to five (5) million pounds of OCPSF products per year, the BPT level of treatment is the best available technology economically achievable. Accordingly, the Agency is not promulgating more stringent BAT limitations for these point sources.(b) Except as provided in paragraph (a) of this section and in 40 CFR 125.30 through 125.32 , any existing point source that uses end-of-pipe biological treatment and is subject to this subpart must achieve discharges in accordance with § 414.91 of this part.(c) Except as provided in paragraph (a) of this section and in 40 CFR 125.30 through 125.32 , any existing point source that does not use end-of-pipe biological treatment and is subject to this subpart must achieve discharges in accordance with § 414.101 of this part.