Yes, POTW treatment plants are divided into two subcategories: Group 1 POTW treatment plants and Group 2 POTW treatment plants, as described in paragraphs (a) through (c) of this section.

(a) Your POTW is a Group 1 POTW treatment plant if an industrial user complies with its NESHAP by using the treatment and controls located at your POTW treatment plant. Your POTW treatment plant accepts the regulated waste stream and provides treatment and controls as an agent for the industrial user. Group 1 POTW treatment plant is defined in § 63.1595.

(b) Your POTW is a Group 2 POTW treatment plant if your POTW treats wastewater that is not subject to control by another NESHAP or the industrial user does not comply with its NESHAP by using the treatment and controls located at your POTW treatment plant. “Group 2 POTW treatment plant” is defined in § 63.1595.

(c) If, in the future, an industrial user complies with its NESHAP by using the treatment and controls located at your POTW treatment plant, then your Group 2 POTW treatment plant becomes a Group 1 POTW treatment plant on the date your POTW begins treating that regulated industrial wastewater stream.