Mechanical sewage treatment in which large solids are filtered out by screens and suspended solids settle out as sludge in a sedimentation tank. Compare advanced sewage treatment, secondary sewage treatment.
The treatment of wastewater to settle out suspended solids in primary sedimentation tanks. It is normal for wastewater to receive preliminary treatment prior to sedimentation.
a system of treating wastewater using screens, gravity, and skimming to remove insoluble particles; this treatment does not reduce dangerous water-soluble organic and inorganic substances
Physical treatment of sewage, designed to remove solids via settling (as sludge) and floatable solids such as oil, fats and grease by first screening and then ponding the effluent.