(1) Post closure care for Class II landfills:

(a) Following closure of each Class II landfill unit, the owner or operator must conduct post-closure care.   Post-closure care must be conducted for 30 years, except as provided under (b) below, and consist of at least the following:

(i) maintaining the integrity and effectiveness of any final cover, including making repairs to the cover as necessary to correct the effects of settlement, subsidence, erosion, or other events, and preventing run-on and run-off from eroding or otherwise damaging the final cover;

(ii) maintaining and operating the leachate collection system in accordance with the requirements in ARM 17.50.506.   The department may allow the owner or operator to stop managing leachate if the owner or operator demonstrates that leachate no longer poses a threat to human health and the environment;

(iii) monitoring the ground water in accordance with the requirements of ARM Title 17, chapter 50, subchapter 7, and maintaining the ground water monitoring system, if applicable; and

(iv) maintaining and operating the gas monitoring system in accordance with the requirements of ARM 17.50.511.

(b) The length of the post-closure care period may be:

(i) decreased by the department if the owner or operator demonstrates that the reduced period is sufficient to protect human health and the environment and this demonstration is approved by the department; or

(ii) increased by the department if the department determines that the lengthened period is necessary to protect human health and the environment.

(c) The owner or operator of all Class II landfill units must prepare a written post-closure plan that includes, at a minimum, the following information:

(i) a description of the monitoring and maintenance activities required in (a) above for each Class II landfill unit, and the frequency at which these activities will be performed;

(ii) name, address, and telephone number of the person or office to contact about the facility during the post-closure period; and

(iii) a description of the planned uses of the property during the post-closure period.   Post-closure use of the property must not disturb the integrity of the final cover, liner(s) , or any other components of the containment system, or the function of the monitoring systems unless necessary to comply with the requirements in these rules.   The department may approve any other disturbance if the owner or operator demonstrates that disturbance of the final cover, liner or other component of the containment system, including any removal of waste, will not increase the potential threat to human health or the environment.

(d) The owner or operator must submit to the department a post-closure plan for approval and place a copy of that plan in the operating record no later than October 9, 1993, or by the initial receipt of waste, whichever is later.

(e) Following completion of the post-closure care period for each Class II landfill unit, the owner or operator must submit to the department a certification, signed by an independent registered professional engineer for approval by the department, verifying that post-closure care has been completed in accordance with the post-closure plan.   A copy of the approved document must be placed in the operating record.

(2) (a) The department hereby adopts and incorporates by reference:

(i) the ground water monitoring requirements contained in ARM Title 17, chapter 50, subchapter 7; and

(ii) ARM 17.50.511, containing requirements for maintaining and operating gas monitoring systems.

(b) Copies of the above rules may be obtained from the Department of Environmental Quality, PO Box 200901, Helena, MT 59620-0901, [(406)444-1430].