Authority: IC 13-14-8; IC 13-15-1-2; IC 13-15-2-1; IC 13-18-2; IC 13-18-3

Affected: IC 13-11-2; IC 13-13-5-1; IC 13-18-4

Sec. 23. (a) Except as provided in subsection (b), "significant industrial user" or "SIU" means the following:

1. (1) Industrial users subject to categorical pretreatment standards under 327 IAC 5-2-1.5.

2. (2) An industrial user that:

   1. (A) discharges an average of twenty-five thousand (25,000) gallons per day or more of process wastewater (excluding sanitary, noncontact cooling and boiler blowdown wastewater) to the POTW;
   2. (B) contributes a process waste stream that makes up five percent (5%) or more of the average dry weather hydraulic or organic capacity of the POTW treatment plant; or

   3. (C) is designated as a significant industrial user by the control authority on the basis that the industrial user has a reasonable potential to:

      1. (i) adversely affect the POTW's operation; or

      2. (ii) violate a:

         1. (AA) pretreatment standard; or
         2. (BB) requirement of 327 IAC 5-19-3.

3. (3) The control authority may determine that an industrial user subject to categorical pretreatment standards under 40 CFR 403.6 and 40 CFR Chapter I, Subchapter N is a nonsignificant categorical industrial user rather than a significant industrial user if the industrial user never discharges more than one hundred (100) gallons per day (gpd) of total categorical wastewater, excluding sanitary, noncontact cooling and boiler blowdown wastewater, unless specifically included in the pretreatment standard and the following conditions are met:

   1. (A) The industrial user, prior to the control authority's finding, has consistently complied with all applicable categorical pretreatment standards and requirements.
   2. (B) The industrial user annually submits the certification statement required in 40 CFR 403.12(q) together with any additional information necessary to support the certification statement.
   3. (C) The industrial user never discharges any untreated concentrated wastewater.

(b) A control authority may:

1. (1) on its own initiative; or
2. (2) in response to a petition received from an industrial user or a POTW and in accordance with 327 IAC 5-19-3(6);

determine that an industrial user is not a significant industrial user if it does not meet subsection (a)(2)(C).

(Water Pollution Control Division; 327 IAC 5-17-23; filed Oct 10, 2000, 3:02 p.m.: 24 IR 296; filed Apr 3, 2009, 1:55 p.m.: 20090429-IR-327060156FRA; filed Sep 6, 2018, 11:50 a.m.: 20181003-IR-327170278FRA; readopted filed Oct 18, 2024, 1:57 p.m.: 20241113-IR-327230810RFA)