25 Pa. Code § 91.6
The Department will encourage pollution prevention by providing assistance to the permittee and users of the permittee's facilities in the consideration of pollution prevention measures such as process changes, materials substitution, reduction in volume of water use, in-process recycling and reuse of water, and by general measures of "good housekeeping" within the plant or facility. The Department will encourage consideration of the following measures, in descending order of preference, for environmental management of wastes: reuse, recycling, treatment and disposal.
25 Pa. Code § 91.6
The provisions of this §91.6 issued under section 5 of The Clean Streams Law (35 P. S. § 691.5); and section 1920-A of The Administrative Code of 1929 (71 P. S. § 510-20).