Sludge produced at a Publicly Owned Treatment Works, the disposal of which is regulated under the Clean Water Act.

a semi-liquid residue that settles to the bottom of canals and pipes carrying sewage or industrial wastewaters, or in the bottom of tanks used in treating wastewaters.

A solid, semisolid, or liquid residue generated during the treatment of domestic sewage in a treatment works. Sewage sludge includes but is not limited to: domestic septage; scum or solids removed in primary, secondary, or advanced wastewater treatment processes; and a material derived from sewage sludge. Sewage sludge does not include ash generated during the firing of sewage sludge in a sewage sludge incinerator or grit and screenings generated during preliminary treatment of domestic sewage in a treatment works. (Note: The use of sewage sludge is not allowed in organic farming.)

the solid constituents of sewage that are removed for subsequent purification.

Settled sewage solids removed by screening, sedimentation, chemical precipitation, or bacterial digestion.

a semi liquid substance consisting of suspended sewage solids combined with water and dissolved material in varying amounts. a

the solid matter that settles out during the treatment of sewage.