For purposes of this article, the following definitions apply:

1. (a) “Discharge” means to place or dispose hazardous wastes in a land treatment unit.
2. (b) “Facility” has the meaning specified in Section 25117.1.
3. (c) “Hazardous constituent” has the meaning specified in regulations adopted by the department.
4. (d) “Hazardous waste” means a hazardous waste, as defined in Section 25117 and “non-RCRA hazardous waste” has the same meaning as defined in Section 25117. 9.
5. (e) “Land treatment unit” means a facility or part of a facility at which hazardous waste is applied onto or incorporated into the soil surface so that hazardous constituents are degraded, transformed, or immobilized within the treatment zone. A land treatment unit is a disposal unit if the waste will remain after closure.
6. (f) “Potential source of drinking water” has the meaning specified in subdivision (s) of Section 25208.2.
7. (g) “Treatment zone” means the portion of a land treatment unit including the soil surface, within which hazardous constituents are degraded, transformed, or immobilized. A treatment zone may not extend more than five feet from the initial soil surface and the base of the treatment zone shall be a minimum of five feet above the highest anticipated elevation of the water table.
8. (h) “Vadose zone” means the unsaturated zone outside the treatment zone and between the land surface and the water table.
9. (i) “Waste management unit” has the meaning specified in the regulations adopted by the department.