40 CFR § 438.10
Applicability
June 9, 2020
(a) This subpart applies to process wastewater directly discharged from facilities specified at §438.1.
(b) This subpart applies to process wastewater discharges from oily operations (as defined at §438.2(f) and appendix B of this part).
(c) This subpart does not apply to process wastewater discharges from metal-bearing operations (as defined at §438.2(d) and appendix C of this part).