Section 725.190  Applicability

a)         The owner or operator of a surface impoundment, landfill, or land treatment facility that is used to manage hazardous waste must implement a groundwater monitoring program capable of determining the facility's impact on the quality of groundwater in the uppermost aquifer underlying the facility, except as Section 725.101 and subsection (c) provide otherwise.

b)         Except as subsections (c) and (d) provide otherwise, the owner or operator must install, operate, and maintain a groundwater monitoring system that meets the requirements of Section 725.191 and must comply with Sections 725.192 through 725.194.  This groundwater monitoring program must be carried out during the active life of the facility and for disposal facilities during the post-closure care period as well.

c)         All or part of the groundwater monitoring requirements of this Subpart F may be waived if the owner or operator can demonstrate that there is a low potential for migration of hazardous waste or hazardous waste constituents from the facility via the uppermost aquifer to water supply wells (domestic, industrial, or agricultural) or to surface water.  This demonstration must be in writing and must be kept at the facility. This demonstration must be certified by a qualified geologist or geotechnical engineer and must establish the following:

1)         The potential for migration of hazardous waste or hazardous waste constituents from the facility to the uppermost aquifer by an evaluation of the following information:

A)        A water balance of precipitation, evapotranspiration, run-off, and infiltration; and

B)        Unsaturated zone characteristics (i.e., geologic materials, physical properties, and depth to ground water); and

2)         The potential for hazardous waste or hazardous waste constituents that enter the uppermost aquifer to migrate to a water supply well or surface water by an evaluation of the following information:

A)        Saturated zone characteristics (i.e., geologic materials, physical properties, and rate of groundwater flow); and

B)        The proximity of the facility to water supply wells or surface water.

d)         If an owner or operator assumes (or knows) that groundwater monitoring of indicator parameters in accordance with Sections 725.191 and 725.192 would show statistically significant increases (or decreases in the case of pH) when evaluated pursuant to Section 725.193(b), it may install, operate, and maintain an alternate groundwater monitoring system (other than the one described in Sections 725.191 and 725.192).  If the owner or operator decides to use an alternate groundwater monitoring system, it must have done as follows:

1)         The owner or operator must develop a specific plan, certified by a qualified geologist or geotechnical engineer, that satisfies the requirements of federal 40 CFR 265.93(d)(3) for an alternate groundwater monitoring system.  This plan is to be placed in the facility's operating record and maintained until closure of the facility;

2)         The owner or operator must have initiated the determinations specified in federal 40 CFR 265.93(d)(4);

3)         The owner or operator must prepare a written report in accordance with Section 725.193(d)(5) and place it in the facility's operating record and maintain until closure of the facility;

4)         The owner or operator must continue to make the determinations specified in Section 725.193(d)(4) on a quarterly basis until final closure of the facility; and

5)         The owner or operator must comply with the recordkeeping and reporting requirements in Section 725.194(b).

e)         The groundwater monitoring requirements of this Subpart F may be waived with respect to any surface impoundment of which the following is true:

1)         The impoundment is used to neutralize wastes that are hazardous solely because they exhibit the corrosivity characteristic pursuant to 35 Ill. Adm. Code 721.122 or which are listed as hazardous wastes in Subpart D of 35 Ill. Adm. Code 721 only for this reason; and

2)         The impoundment contains no other hazardous wastes, if the owner or operator can demonstrate that there is no potential for migration of hazardous wastes from the impoundment.  The demonstration must establish, based upon consideration of the characteristics of the wastes and the impoundment, that the corrosive wastes will be neutralized to the extent that they no longer meet the corrosivity characteristic before they can migrate out of the impoundment. The demonstration must be in writing and must be certified by a qualified professional.

f)         A permit or enforceable document can contain alternative requirements for groundwater monitoring that replace all or part of the requirements of this Subpart F applicable to a regulated unit (as defined in 35 Ill. Adm. Code 724.190), as provided pursuant to 35 Ill. Adm. Code 703.161, where the Board has determined by an adjusted standard granted pursuant to Section 28.1 of the Act and Subpart D of 35 Ill. Adm. Code 104 the following:

1)         The regulated unit is situated among solid waste management units (or areas of concern), a release has occurred, and both the regulated unit and one or more solid waste management units (or areas of concern) are likely to have contributed to the release; and

2)         It is not necessary to apply the groundwater monitoring requirements of this Subpart F because the alternative requirements will adequately protect human health and the environment.  The alternative standards for the regulated unit must meet the requirements of 35 Ill. Adm. Code 724.201(a).

(Source:  Amended at 43 Ill. Reg. 6049, effective May 2, 2019)