Section 352.430  Instances Requiring Effluent Limits, Other Conditions, or Additional Data

The Agency will consider the following factors when determining whether further data needs to be gathered in order to decide if a reasonable potential to exceed water quality standards exists. These factors may also warrant inclusion of a permit limit for a substance or substances that do not display a reasonable potential to exceed through the analysis of  Sections 352.420 through 352.425.

a)         The facility's effluent is subject to federal categorical limits under 40 CFR 405 through 471 for the substance.

b)         A substance(s) is present in the raw wastewater in significant quantities such that treatment at the facility is designed to remove that substance.

c)         A substance is discharged in quantities that are sufficient to warrant limits in the permit due to batch or highly variable waste generation processes wherein substances are potentially discharged infrequently or sporadically and therefore may avoid detection by intermittent sampling of the final effluent.

d)         The facility has a record of spill events involving certain substances and there is evidence that those substances are discharged in quantities that are sufficient to merit inclusion of permit limits.

e)         Historical information or the knowledge of Agency field inspectors indicate that a potential for discharge of a substance exists  and there is evidence that the substance would be  discharged in quantities sufficient to merit inclusion of permit limits.

f)         For each pollutant listed in Table 6 to 40 CFR 132 (1996) which a permittee reports as known or believed to be present in its discharge and for which data sufficient to calculate tier II values for noncancer human health and acquatic life do not exist all of the following provisions apply:

1)         The Agency shall use all available, relevant toxicity information to estimate ambient screening values for the pollutant that will protect humans from noncancer health effects and aquatic life from acute and chronic effects.

2)         Using the provisions specified in Section 352.423, the Agency shall develop a PEL based on the estimated ambient screening value as determined in subsection (f)(1) of this Section, and compare the PEL with the PEQ.  If the PEQ exceeds the PEL, then the Agency shall generate the minimum data necessary to derive tier II values for noncancer human health and aquatic life.

3)         The data generated in accordance with subsection (f)(2) of this Section shall be used to calculate water quality values.  The values shall be used in calculating a PEL pursuant to Section 352.423 for the purpose of determining whether a WQBEL must be included in the permit.  If the Agency finds that the PEQ exceeds the PEL, the Agency shall follow the procedures under Section 352.424 to determine whether a WQBEL must be established in the permit.