What is a clarifier in wastewater treatment plant? Sedimentation tanks have been used to treat wastewater and in primary treatment for sewage involves the removal of floating and settlable solids through sedimentation.
Clarifiers are settling tanks for the continuous removal of solids. A clarifier is generally used to remove solid particulates or suspended solids from liquid for clarification and thickening. Concentrated impurities discharged from the bottom of the tank are known as sludge, while the particles that float to the surface of the liquid are called scum.
How The Clarification Occurs
Coagulation and flocculation reagents, such as polyelectrolytes and ferric are added before the water enters the clarifier to cause finely suspended particles to clump together and form larger and denser particles, called flocs. These settle more quickly and in a stable manner allowing allows the separation of the solids in the clarifier to occur more efficiently and easily.
Primary clarifiers reduce the content of suspended solids and pollutants embedded in suspended solids. A large number of reagents necessary to treat domestic wastewater, preliminary chemical coagulation and flocculation are generally not used in domestic wastewater treatment systems but can be used for building a compact/complete wastewater treatment plant or for further polishing of the treated water.
Sedimentation Tanks or Secondary Clarifiers
Sedimentation tanks or secondary clarifiers remove flocs of biological growth created in some methods of secondary treatment including activated sludge and rotating biological processes. These secondary clarifiers are generally used to remove the bacteria and other microorganisms and removed floc is usually recycled back to the processes where the cycle continues.