Unless a different meaning is plainly required by the context, the following words as hereinafter used in this chapter shall have the following meanings:

(1) "Facility" shall mean an "air pollution control facility" or a "water pollution control facility" as herein defined: (a) "Air pollution control facility" includes any treatment works, control devices and disposal systems, machinery, equipment, structures, property or any part or accessories thereof, installed or acquired for the primary purpose of reducing, controlling or disposing of industrial waste which if released to the outdoor atmosphere could cause air pollution. "Air pollution control facility" shall not mean any motor vehicle air pollution control devices used to control the emission of air contaminants from any motor vehicle. (b) "Water pollution control facility" includes any treatment works, control device or disposal system, machinery, equipment, structures, property or any accessories thereof installed or acquired for the primary purpose of reducing, controlling or disposing of sewage and industrial waste which if released to a water course could cause water pollution: PROVIDED, That the word "facility" shall not be construed to include any control device, machinery, equipment, structure, disposal system or other property installed or constructed: For a municipal corporation other than for coal-fired, steam electric generating plants constructed and operated pursuant to chapter 54.44 RCW for which an application for a certificate was made no later than December 31, 1969, together with any air or water pollution control facility improvement which may be made hereafter to such plants; or for the primary purpose of connecting any commercial establishment with the waste collecting facilities of public or privately owned utilities: PROVIDED FURTHER, That the word "facility" shall not include any control device, machinery, equipment, structure, disposal system, or other property installed or constructed with the proceeds derived from the sale of industrial revenue bonds issued under chapter 39.84 RCW.

(2) "Industrial waste" shall mean any liquid, gaseous, radioactive or solid waste substance or combinations thereof resulting from any process of industry, manufacture, trade or business, or from the development or recovery of any natural resources.

(3) "Treatment works" or "control device" shall mean any machinery, equipment, structure or property which is installed, constructed or acquired for the primary purpose of controlling air or water pollution and shall include, but shall not be limited to such devices as precipitators, scrubbers, towers, filters, baghouses, incinerators, evaporators, reservoirs, aerators used for the purpose of treating, stabilizing, incinerating, holding, removing or isolating sewage and industrial wastes.

(4) "Disposal system" shall mean any system containing treatment works or control devices and includes but is not limited to pipelines, outfalls, conduits, pumping stations, force mains, solids handling equipment, instrumentation and monitoring equipment, ducts, fans, vents, hoods and conveyors and all other construction, devices, appurtenances and facilities used for collecting or conducting, sewage and industrial waste to a point of disposal, treatment or isolation except that which is necessary to manufacture of products.

(5) "Certificate" shall mean a pollution control tax exemption and credit certificate for which application has been made not later than December 31, 1969, except as follows:

(a) With respect to a facility required to be installed, such application will be deemed timely made if made not later than November 30, 1981, and within one year after the effective date of specific requirements for such facility promulgated by the appropriate control agency.

(b) With respect to a water pollution control facility for which an application was made in anticipation of specific requirements for such facility being promulgated by the appropriate control agency, an application will be deemed timely made if made during November, 1981, and subsequently denied, and if an appeal of the agency's denial of the application was filed in a timely manner.

(c) With respect to a facility for which plans and specifications were approved by the appropriate control agency, an application will be deemed timely made if made during November, 1981, and subsequently denied, and if an appeal of the agency's denial of the application was filed in a timely manner.

(d) For the purposes of (a), (b), and (c) of this subsection, "facility" means a facility installed in an industrial, manufacturing, waste disposal, utility, or other commercial establishment which is in operation or under construction as of July 30, 1967.

(6) "Appropriate control agency" shall mean the department of ecology; or the operating local or regional air pollution control agency within whose jurisdiction a facility is or will be located, or the department of ecology, where the facility is not or will not be located within the area of an operating local or regional air pollution control agency, or where the department of ecology has assumed jurisdiction.

(7) "Department" shall mean the department of revenue.