(a) Utilizing the provisions of Section 28.1 and this Section alternative requirements may be established by the Board in an adjusted standards proceeding for the direct discharge of waste solids to the Mississippi or Ohio Rivers from clarifier sludge and filter backwash generated in the water purification process. Any public water supply utilizing the Mississippi or Ohio Rivers as its raw water source may initiate such a proceeding provided that its waste solids are generated as described herein and it does not utilize lime softening in the purification process. An adjusted standard granted by the Board in an adjusted standard proceeding shall be based upon water quality effects, actual and potential stream uses, and economic considerations, including those of the discharger and those affected by the discharge.(b) No later than January 1, 1991, the public water supply shall make a declaration regarding the intent to pursue an adjusted standard and assemble and submit to the Agency any background information in its possession relevant to current discharge practices. The Agency, after a review of its files and the submittal, shall request such further information as it deems necessary for its initial determination. The Agency shall promptly notify the public water supply in writing of any discretionary determination that it will not agree with pursuit of an adjusted standard and shall indicate the basis for such determination. Such basis may include but not be limited to a judgment that the information submitted is insufficient, that due to the nature of the discharge an adjusted standard would be environmentally unsound, or that a specific alternative control strategy being considered by the supply is infeasible from either an engineering or pollutant removal standpoint. If the supply and the Agency agree on alternative controls, an adjusted standard proceeding before the Board shall be commenced by the supply by filing jointly with the Agency a petition. If the Agency has declined to agree with an alternate control strategy or if the supply declines to accept an Agency proposal, the supply may commence singly an adjusted standard proceeding before the Board.(c) If the public water supply and the Agency jointly file an adjusted standard petition, justifications shall be included in the petition. Justification based upon discharge impact shall include, as a minimum, an evaluation of receiving stream ratios, known stream uses, accessibility to stream and side land use activities (residential, commercial, agricultural, industrial, recreational), frequency and extent of discharges, inspections of unnatural bottom deposits, odors, unnatural floating material or color, stream morphology and results of stream chemical analyses. Where minimal impact cannot be established, justification shall also include evaluations of stream sediment analyses, biological surveys (including habitat assessment), and thorough stream chemical analyses that may include but are not limited to analysis of parameters regulated in 35 Ill. Adm. Code 302. Except as otherwise provided in this Section, the petitioner shall adhere to the general procedural rules for adjusted standards petitions as adopted by the Board. If the petitioner files singly, justification shall include all components identified as applicable to instances where minimal impact cannot be established.(d) Any petition submitted pursuant to this Section shall include the following: (1) A written statement, signed by the petitioners or their authorized representatives, outlining the scope of the evaluation, the nature of, the reasons for, and the basis for the justification for the adjusted standard;(2) Citations to any final enforcement actions against the petitioner and any variances granted to the petitioner where compliance has not been achieved;(3) A description of the proposed alternative control strategy and the discharge limitations associated with said alternative strategy; and(4) A compliance schedule and effective date for attainment of the adjusted standard. No petition for an adjusted standard filed under this Section shall be accepted by the Board after January 1, 1992.(e) The Board shall give notice of the petition and shall schedule a hearing in accordance with 35 Ill. Adm. Code 103. The proceedings shall be in accordance with 35 Ill. Adm. Code 103.(f) In considering the proposed petition and the hearing record, the Board shall take into account the factors contained in subsection (a) of Section 27 of this Act. The Board shall issue and enter a written opinion stating the facts and reasons leading to its decision within 120 days after the filing of the petition. The Board shall issue and enter such orders concerning a petition for an adjusted standard as are appropriate for the reasons stated in its written opinion. Such decisions may include but are not limited to decisions accepting or rejecting the petition, directing that hearings be held to develop further information or to cure any procedural defects, or remanding the petition to the petitioners with suggested revisions. The Board shall also include a compliance schedule for construction of any treatment works, discharge outfall facilities or operational controls that may be required as a result of its final order.(g) Application of otherwise applicable discharge limitations to discharges subject to this Section shall be held in abeyance pending Board action for those petitioners pursuing an adjusted standard as long as they have adhered to the filing times in this Section and are making timely and appropriate progress in seeking an adjusted standard. Petitioners must take all reasonable steps to minimize discharge quantities and adverse environmental impacts for the interim operating period during pursuit of an adjusted standard. In no instances shall interim operating procedures be relaxed from previously demonstrated and generally attainable performance levels.