In addition to the terms defined in 75-10-203, MCA, as used in this subchapter, the following terms shall have the meanings or interpretations shown below:

(1) "Act" means the Montana Solid Waste Management Act, 75-10-201 through 75-10-233, MCA.

(2) "Active life" means the period of operation beginning with the initial receipt of solid waste and ending at completion of closure activities in accordance with ARM 17.50.530.

(3) "Active portion" means that part of a facility or unit that has received or is receiving wastes and that has not been closed in accordance with ARM 17.50.530.

(4) "Airport" means a public use airport open to the public without prior permission and without restrictions within the physical capacities of available facilities.

(5) "Aquifer" means any geologic formation, group of formations, or part of a formation capable of yielding significant quantities of ground water to wells or springs.

(6) "Clean fill" means soil, dirt, sand, gravel, rocks and rebar-free concrete, emplaced free of charge to the person placing the fill, in order to adjust or create topographic irregularities for agricultural or construction purposes.

(7) "Closed unit" means any solid waste disposal unit, trench, cell or area that no longer receives solid waste and has been closed in accordance with department rules.

(8) "Closure" means the process by which an owner or operator of a facility closes all or part of a facility in accordance with a department approved closure plan and all applicable closure requirements specified in ARM 17.50.530.

(9) "Compacted soil liner" means recompacted native or amended soil with a minimum thickness of 3 feet with adequate moisture content and compaction to achieve a hydraulic conductivity of less than or equal to 1 x 10^-7 cm/sec.

(10) "Commercial waste" means all types of solid wastes generated by stores, offices, restaurants, warehouses, and other non-manufacturing activities, and non-processing wastes such as office and packing wastes generated at industrial facilities.

(11) "Conditionally exempt small quantity generator wastes (CESQG wastes) " means wastes from a generator defined in ARM 17.54.401(4) (c) .

(12) "Construction and demolition waste" means the waste building materials, packaging, and rubble resulting from construction, remodeling, repair, and demolition operations on pavements, houses, commercial buildings, and other structures, once municipal, household, commercial and industrial wastes have been removed.

(13) "Container site" means a solid waste management facility, generally open to the public, for the collection of solid waste that is generated by more than one household or firm and that is collected in a refuse container with a totalcapacity of not more than 50 cubic yards.

(14) "Cost" means all expenses associated with the permitting, licensing, design, construction, environmental compliance, operation, maintenance, ground water monitoring, corrective action, closure and post-closure care of any facility.

(15) "Director" means the chief administrative officer of the department of environmental quality.

(16) "Disease vectors" means any rodents, flies, mosquitoes, or other animals, including insects, capable of transmitting disease to humans.

(17) "EPA" means the United States environmental protection agency.

(18) "Existing unit" means any solid waste disposal unit that is receiving solid waste as of October 9, 1993.   Waste placement in existing units must be consistent with past operating practices or modified practices to ensure good management.

(19) "Facility" means a manufacturing, processing or assembly establishment; a transportation terminal; or a treatment, storage or disposal unit operated by a person at one site.   The term includes all contiguous land and structures, other appurtenances, and improvements on the land (licensed or unlicensed) used for the storage, treatment or disposal of solid waste.

(20) "Floodplain" means the lowland and relatively flat areas adjoining inland waters, including flood-prone areas, that are inundated by the 100-year flood.

(21) "Generation" means the act or process of producing waste materials.

(22) "Ground water class" means a ground water quality classification established in ARM 17.30.1002.

(23) "Ground water quality standards" means the standards for ground water quality set forth in ARM 17.30.1003.

(24) "Industrial solid waste" means solid waste generated by manufacturing or industrial processes that is not a hazardous waste regulated under subtitle C of the federal Resource Conservation and Recovery Act (RCRA) .   The term includes, but is not limited to, waste resulting from the following manufacturing processes:   electric power generation; fertilizer/agricultural chemicals; food and related products/byproducts; inorganic chemicals; iron and steel manufacturing; leather and leather products; nonferrous metals manufacturing/foundries; organic chemicals; plastics and resins manufacturing; pulp and paper industry; rubber and miscellaneous plastic products; stone, glass, clay, and concrete products; textile manufacturing; transportation equipment; and water treatment.

(25) "Infectious waste" means waste defined in 75-10-1003(4) , MCA.

(26) "Land application unit" means an area where wastes are applied onto or incorporated into the soil surface (excluding manure spreading operations) for agricultural purposes or for treatment and disposal.

(27) "Landfill" means an area of land or an excavation where wastes are placed for permanent disposal, and that is not a land application unit, surface impoundment, injection well, or waste pile.

(28) "Lateral expansion" means a horizontal expansion of the waste boundaries of an existing disposal unit.

(29) "Leachate" means a liquid which has contacted, passed through, or emerged from solid waste and contains soluble, suspended, or miscible materials removed from the waste.

(30) "Liquid waste" means any waste material that is determined to contain "free liquids" as defined by Method 9095 (Paint Filter Liquids Test) , as described in "Test Methods for Evaluating Solid Wastes, Physical/Chemical Methods" (EPA Pub. No. SW-846) .

(31) "Lower explosive limit" means the lowest percent by volume of a mixture of explosive gases in air that will propagate a flame at 25ēC and atmospheric pressure.

(32) "Maximum horizontal acceleration" means the maximum expected horizontal acceleration depicted on a seismic hazard map, with a 90% or greater probability that the acceleration will not be exceeded in 250 years, or the maximum expected horizontal acceleration based on a site-specific seismic risk assessment.

(33) "Municipal solid waste landfill unit (or MSWLF unit) " means a discrete area of land or an excavation that receives household waste, and that is not a land application unit, surface impoundment, injection well, or waste pile.   A MSWLF unit also may receive other types of RCRA subtitle D wastes, such as commercial solid waste, nonhazardous sludge, conditionally exempt small quantity generator waste, and industrial solid waste.   Such a landfill may be publicly or privately owned.   A MSWLF unit may be a new MSWLF unit, an existing MSWLF unit, or a lateral expansion.

(34) "New unit" means any solid waste disposal unit that has not received waste prior to October 9, 1993.

(35) "Open burning" means the combustion of solid waste without:

(a) control of combustion air to maintain adequate temperature for efficient combustion;

(b) containment of the combustion reaction in an enclosed device to provide sufficient residence time and mixing for complete combustion; and

(c) control of the emission of the combustion products.

(36) "Operator" means the person responsible for the overall operation of a facility or part of a facility.

(37) "Owner" means the person who owns a facility or part of a facility.

(38) "PCB wastes" means those polychlorinated biphenyls or PCB items subject to regulation under 40 CFR Part 761.

(39) "Qualified ground water scientist" means a scientist or engineer who has received a baccalaureate or post-graduate degree in 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 judgements regarding ground water monitoring, contaminant fate and transport, and corrective action.

(40) "Refuse container" means a portable facility used for the temporary storage of solid waste.   Containers are emptied periodically and the solid waste is then taken to a disposal or resource recovery facility.

(41) "Regulated hazardous waste" means a solid waste that is a hazardous waste, as defined in 40 CFR 261.3, that is not excluded from regulation as a hazardous waste under 40 CFR 261.4(b) or was not generated by a conditionally exempt small quantity generator as defined in 40 CFR 261.5.

(42) "Run-off" means any rainwater, leachate, or other liquid that drains over land from any part of a facility.

(43) "Run-on" means any rainwater, leachate, or other liquid that drains over land onto any part of a facility.

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

(45) "Seismic impact zone" means an area with a 10% or greater probability that the maximum horizontal acceleration in lithified earth material, expressed as a percentage of the earth's gravitational pull (g) , will exceed 0.10g in 250 years.

(46) "Sewage sludge" means solid, semi-solid, or liquid residue generated during the treatment of domestic sewage in a treatment works.   Sewage sludge includes, but is not limited to, domestic septage; scum or solids removed in primary, secondary, or advanced wastewater treatment processes; and a material derived from sewage sludge.   Sewage sludge does not include ash generated during the firing of sewage sludge in a sewage sludge incinerator or grit and screenings generated during the preliminary treatment of domestic sewage in a treatment plant.

(47) "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.

(48) "Solid waste management system" as defined in 75-10-203, MCA, means a system which controls the storage, treatment, recycling, recovery, or disposal of solid waste.   In

addition, for the purposes of this definition, the department does not consider a container site to be a component of a solid waste management system.

(49) "Structural components" means liners, leachate collection systems, final covers, run-on/run-off systems, and any other component used in the construction and operation of a solid waste management system that is necessary for protection of human health and the environment.

(50) "Surface impoundment" means a facility or part of a facility that is a natural topographic depression, human made excavation, or diked area formed primarily of earthen materials (although it may be lined with human made materials) , that is designed to hold an accumulation of liquid wastes or wastes containing free liquids and is not an injection well.   Examples of surface impoundments are holding, storage, settling, and aeration pits, ponds, and lagoons.

(51) "Transfer station" means a solid waste management facility that can have a combination of structures, machinery, or devices, where solid waste is taken from collection vehicles (public, commercial or private) and placed in other transportation units for movement to another solid waste management facility.

(52) "Unit" means a discrete area of land or an excavation used for the landfilling or other disposal of solid waste.

(53) "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.

(54) "Waste" means useless, unwanted, or discarded materials in any physical form, i.e., solid, semi-solid, liquid, or gaseous.   The term is not intended to apply to by-products or materials which have economic value and may be used by the person producing the material or sold to another person for resource recovery or use in a beneficial manner.

(55) "Waste management unit boundary" means a vertical surface located at the hydraulically downgradient limit of the unit.   This vertical surface extends down into the uppermost aquifer.

(56) "Waste pile" or "pile" means any noncontainerized accumulation of solid, nonflowing waste that is used for treatment or storage.

(57) "Wetlands" means those areas that are inundated or saturated by surface or ground water at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions.   Wetlands generally include swamps, marshes, bogs and similar areas.