For purposes of this part, "sludge" means solid waste that is a nonhazardous solid, semi-solid, or liquid residue generated by the treatment of domestic sewage or wastewater by a treatment works or water by a water supply system, or such residue, treated or untreated, which results from commercial, agricultural or agribusiness activities or industrial or manufacturing processes and which is subject to the jurisdiction of the Department.
Okla. Stat. tit. 27A, § 2-10-401