Ill. Admin. Code tit. 35, § 352.700 – Water Quality Based Effluent Limits Below Detection or Quantification

a) When a WQBEL for a toxic substance is calculated to be less than the quantification level, the permit shall include a discharge limit, method and quantification level consistent with the following:
1. 1) The permit shall include the WQBEL as calculated.
2. 2) The permit shall specify the most sensitive applicable analytical method adopted by the Board and contained in or approved under 40 CFR 136, or other appropriate method adopted by the Board if one is not available under 40 CFR 136. The analytical method adopted by the Board and specified in the permit shall be the method used for compliance assessment including enforcement actions.
3. 3) The permit shall also identify the quantification level that can be achieved with the method specified pursuant to subsection (a)(2). That quantification level shall be the minimum level (ML) specified in or approved under 40 CFR 136 for the selected method for the toxic substance. If no such ML exists, or if the method is not specified or approved under 40 CFR 136, the quantification level shall be the lowest quantifiable level practicable. In determining the practicability of a method, the Agency shall consider achievability of the identified detection level by competent commercial laboratories.
4. 4) A higher quantification level may be established if demonstrated to be appropriate due to effluent-specific matrix interference. The Agency may consider alternative methods adopted by the Board for deriving quantification levels if those methods are demonstrated to be scientifically defensible.
b) The permit shall include a condition requiring the permittee to develop and conduct a pollutant minimization program (PMP) for each pollutant with a WQBEL below the quantification level, unless the permittee can demonstrate that an alternative technique is adequate to assess compliance with the WQBEL. The goal of the PMP shall be to attain and maintain the discharge at or below the WQBEL. The PMP shall include but is not limited to the following:
1. 1) An annual review of potential sources of the toxic substance;
2. 2) Periodic monitoring as necessary in order to assess progress toward the goal of the PMP;
3. 3) Implementation of appropriate cost-effective control measures at the earliest practicable time after sources are identified; and
4. 4) Submittal of an annual, unless otherwise specified in the permit, status report containing all minimization program monitoring results of the reporting period, a listing of potential sources of the toxic substance, a summary of all actions and control measures taken to reduce or eliminate the identified sources of the toxic substance and an overview of anticipated future steps in the PMP.
c) The permit may contain a condition requiring fish tissue monitoring, other bio-uptake sampling, facility sludge monitoring, or a combination of such sampling as necessary to assess the progress of the PMP.
d) The permit shall contain a reopener clause providing for subsequent modification or revocation and reissuance of the permit as warranted by the results of the PMP pursuant to subsection (b), or the availability of new or alternative analytical methods. Such modification or reissuance may accommodate more or less frequent monitoring, a new alternative analytical method or quantification level, or both if appropriate and consistent with subsection (a)(3), or modification or removal of the PMP.