(a) At closure, the owner or operator must:
(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 § 261.3(d) of this chapter applies; or
(2) Close the impoundment and provide post-closure care for a landfill under subpart G and § 265.310, including the following:
(i) Eliminate free liquids by removing liquid wastes or solidifying the remaining wastes and waste residues;
(ii) Stabilize remaining wastes to a bearing capacity sufficient to support the final cover; and
(iii) Cover the surface impoundment with a final cover designed and constructed to:
(A) Provide long-term minimization of the migration of liquids through the closed impoundment;
(B) Function with minimum maintenance;
(C) Promote drainage and minimize erosion or abrasion of the cover;
(D) Accommodate settling and subsidence so that the cover's integrity is maintained; and
(E) Have a permeability less than or equal to the permeability of any bottom liner system or natural subsoils present.
(b) In addition to the requirements of subpart G, and § 265.310, during the post-closure care period, the owner or operator of a surface impoundment in which wastes, waste residues, or contaminated materials remain after closure in accordance with the provisions of paragraph (a)(2) of this section must:
(1) Maintain the integrity and effectiveness of the final cover, including making repairs to the cover as necessary to correct the effects of settling, subsidence, erosion, or other events;
(2) Maintain and monitor the leak detection system in accordance with §§ 264.221(c)(2)(iv) and (3) of this chapter and 265.226(b) and comply with all other applicable leak detection system requirements of this part;
(3) Maintain and monitor the ground-water monitoring system and comply with all other applicable requirements of subpart F of this part; and
(4) Prevent run-on and run-off from eroding or otherwise damaging the final cover.