327 IAC 5-10-2 Phosphorus removal

Sec. 2. (a) Phosphorus removal or control facilities shall be required for a point source discharge where: (1)(A) the daily discharge, as a monthly average, contains ten (10) pounds or more of total phosphorus (calculated as elemental phosphorus – P); and (B)(i) the discharge is located within the Lake Michigan or Lake Erie Basins; or (ii) the discharge directly enters a lake or reservoir or enters a tributary within forty (40) miles upstream of a lake or reservoir; or (2) the commissioner determines, irrespective of the quantitative total phosphorus content of the discharge, that phosphorus reduction is needed to protect downstream water uses or to insure that water quality standards applicable to the affected waters of the state are met. (b) Where phosphorus removal is required under subsection (a) for a POTW, the treatment facility shall achieve a degree of reduction in total phosphorus in the discharge (calculated as elemental phosphorus) as prescribed in Table I below, or produce an effluent containing no more than 1.0 mg/l of elemental phosphorus as a monthly average, whichever is more stringent. Table I Phosphorus (P) Level in Raw Sewage (In mg/l) Required % Removed (%) greater than or equal to 4 80% less than 4, greater than or equal to 3 75% less than 3, greater than or equal to 2 70% less than 2, greater than or equal to 1 65% less than 1 60% (c) Where phosphorus removal is required under subsection (a) for a point source other than a POTW, the amount of total phosphorus (calculated as elemental phosphorus) in the discharge from said source shall be reduced by at least ninety (90) percent, unless the person owning or operating the point source can affirmatively demonstrate that such degree of phosphorus reduction is technologically infeasible and that an alternate reduction rate is warranted because of factors unique to his facility. (d) Notwithstanding subsection (b) or (c), a point source shall achieve the degree of phosphorus reduction necessary to comply with an applicable water quality standard for phosphorus.