Section 724.328  Closure and Post-Closure Care

a)         At closure, the owner or operator must do the following:

1)         Remove or decontaminate all waste residues, contaminated containment system components (liners, etc.), contaminated subsoils and structures, and equipment contaminated with waste and leachate, and manage them as hazardous waste, unless 35 Ill. Adm. Code 721.103(d) applies; or

2)         Closure in Place

A)        Eliminate free liquids by removing liquid wastes or solidifying the remaining wastes and waste residues;

B)        Stabilize remaining wastes to a bearing capacity sufficient to support final cover; and

C)        Cover the surface impoundment with a final cover designed and constructed to do the following:

i)          Provide long-term minimization of the migration of liquids through the closed impoundment;

ii)         Function with minimum maintenance;

iii)        Promote drainage and minimize erosion or abrasion of the final cover;

iv)        Accommodate settling and subsidence so that the cover's integrity is maintained; and

v)         Have a permeability less than or equal to the permeability of any bottom liner system or natural subsoils present.

b)         If some waste residues or contaminated materials are left in place at final closure, the owner or operator must comply with all post-closure requirements contained in Sections 724.217 through 724.220, including maintenance and monitoring throughout the post-closure care period (specified in the permit under Section 724.217). The owner or operator must do the following:

1)         Maintain the integrity and effectiveness of the final cover, including making repairs to the cap, as necessary to correct the effects of settling, subsidence, erosion, or other events;

2)         Maintain and monitor the LDS in accordance with Sections 724.321(c)(2)(D) and (c)(3) and 724.326(d), and comply with all other applicable LDS requirements of this Part;

3)         Maintain and monitor the groundwater monitoring system and comply with all other applicable requirements of Subpart F; and

4)         Prevent run-on and run-off from eroding or otherwise damaging the final cover.

c)         Contingent Plans

1)         If an owner or operator plans to close a surface impoundment in accordance with subsection (a)(1), and the impoundment does not comply with the liner requirements of Section 724.321(a) and is not exempt from them in accordance with Section 724.321(b), then the following apply:

A)        The closure plan for the impoundment under Section 724.212 must include both a plan for complying with subsection (a)(1) and a contingent plan for complying with subsection (a)(2) in case not all contaminated subsoils can be practicably removed at closure; and

B)        The owner or operator must prepare a contingent post-closure plan under Section 724.218 for complying with subsection (b) in case not all contaminated subsoils can be practicably removed at closure.

2)         The cost estimates calculated under Sections 724.242 and 724.244 for closure and post-closure care of an impoundment subject to this subsection (c) must include the cost of complying with the contingent closure plan and the contingent post-closure plan, but are not required to include the cost of expected closure under subsection (a)(1).

(Source:  Amended at 42 Ill. Reg. 22614, effective November 19, 2018)