(1) For the purpose of this rule, "grease interceptor" and "grease trap" mean grease trap. Oil/water separators at commercial and industrial facilities are not grease traps.

(2) Grease trap waste may not be discharged to a treatment works not specifically designed to manage the waste.

(3) Grease trap waste may be dewatered at a permitted wastewater treatment works designed in conformance with Department Circular DEQ-2, Design Standards for Public Sewage Systems, a solid waste management system licensed in conformance with Title 75, chapter 10, part 2, MCA, or at a land application site approved in conformance with this subchapter.

(4) A person licensed under this subchapter may dewater grease trap waste where the waste is produced. An owner or lessee of property from which grease trap waste is removed may dewater grease trap waste on property owned or leased by the owner or lessee if the property has an area greater than five acres and if the dewatering does not constitute a nuisance or public health hazard and is not harmful to human health or the environment.

(5) The water from a grease trap dewatering process is commercial wastewater. It may be discharged to an individual commercial wastewater treatment system or approved wastewater treatment facility. The water may be land-applied at an approved septage land application site.

(6) Dewatered grease trap waste may be disposed of at a licensed Class II solid waste management facility.

(7) Grease trap waste, dewatered or not, may be:

(a) composted at a licensed compost facility;

(b) treated at a rendering plant; or

(c) land-applied under the following conditions:

(i) in accordance with ARM 17.50.811(3)(a) or (b) for disposal of septage; or

(ii) in accordance with ARM 17.50.810 when special conditions exist.

(8) The department may approve other methods for handling grease trap waste on a case-by-case basis. A person may not dispose of grease trap waste other than by landfilling at a licensed solid waste management system, management in conformance with this rule, or disposal in a permitted treatment works unless the person has first submitted a written application to the department and received the department's written determination that the proposed disposal methods are at least as protective of human health and the environment as the requirements of this subchapter.