Okla. Stat. tit. 27A, § 27A-2-10-401: Sludge defined

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.