Cal. Public Resources Code § 40200

(a) “Transfer or processing station” or “station” includes those facilities utilized to receive solid wastes, temporarily store, separate, convert, or otherwise process the materials in the solid wastes, or to transfer the solid wastes directly from smaller to larger vehicles for transport, and those facilities utilized for transformation. (b) “Transfer or processing station” or “station” does not include any of the following: (1) A facility, whose principal function is to receive, store, separate, convert, or otherwise process in accordance with state minimum standards, manure. (2) A facility, whose principal function is to receive, store, convert, or otherwise process wastes that have already been separated for reuse and are not intended for disposal. (3) The operations premises of a duly licensed solid waste handling operator who receives, stores, transfers, or otherwise processes wastes as an activity incidental to the conduct of a refuse collection and disposal business in accordance with regulations adopted pursuant to Section 43309. (4) An EMSW conversion facility.