In this subchapter, the following definitions apply:

(1) "Appendix I to 40 CFR Part 258" means the appendix from the July 1, 2008, Code of Federal Regulations, as set forth in ARM 17.50.1306.

(2) "Appendix II to 40 CFR Part 258" means the appendix from the July 1, 2008, Code of Federal Regulations, as set forth in ARM 17.50.1307.

(3) "Aquifer" has the meaning given in ARM 17.50.1002.

(4) "Class II landfill facility" has the meaning given in ARM 17.50.504.

(5) "Class IV landfill facility" has the meaning given in ARM 17.50.504.

(6) "Closure" has the meaning given in ARM 17.50.502.

(7) "Department" has the meaning given in ARM 17.50.502.

(8) "Disposal" has the meaning given in 75-10-203(3), MCA.

(9) "Existing," when used in conjunction with "unit" or a type of unit, has the meaning given in ARM 17.50.502.

(10) "Facility" has the meaning given in ARM 17.50.502.

(11) "Ground water" has the meaning given in ARM 17.50.502.

(12) "Landfill" has the meaning given in ARM 17.50.502.

(13) "Lateral expansion" has the meaning given in ARM 17.50.502.

(14) "New," when used in conjunction with "unit" or a type of unit, has the meaning given in ARM 17.50.502.

(15) "Operator" has the meaning given in ARM 17.50.502.

(16) "Owner" has the meaning given in ARM 17.50.502.

(17) "Post-closure care" has the meaning given in ARM 17.50.502.

(18) "Qualified ground water scientist" means a scientist or engineer who has received a baccalaureate or post-graduate degree in the natural sciences or engineering and has sufficient training and experience in ground water hydrology and related fields, as may be demonstrated by state registration, professional certifications, or completion of accredited university programs, that enable that individual to make sound professional judgments regarding ground water monitoring, contaminant fate and transport, and corrective action.

(19) "Saturated zone" means that part of the earth's crust in which all voids are filled with water.

(20) "Sludge" means any solid, semi-solid, or liquid waste generated from a municipal, commercial, or industrial wastewater treatment plant, water supply treatment plant, or air pollution control facility, exclusive of the treated effluent from a wastewater treatment plant.

(21) "Underground drinking water source" means:

(a) an aquifer supplying drinking water for human consumption; or

(b) an aquifer in which the ground water contains less than 10,000 mg/L total dissolved solids.

(22) "Unit" has the meaning given in ARM 17.50.502.

(23) "Uppermost aquifer" means the geologic formation nearest the natural ground surface that is an aquifer, as well as lower aquifers that are hydraulically interconnected with this aquifer within the facility's property boundary.