Vertical-Flow Wastewater Sedimentation Tank For Sewage Treatment
The process to eliminate all impurities present as suspended particles which are carried along by flowing raw waters but which will settle in quiescent or semi-quiescent conditions is called sedimentation. It is usually considered the minimum treatment for turbid surface waters; if 24 hours can be alotted for sedimentation, clarified waters can be directly chlorinated. The sun’s bactericidal effect has also been documented. Below a certain particle size, depending on the material concerned, settling velocity becomes very small and therefore sedimentation becomes unfeasible. This is the case for colloidal matter, which, as it has been discussed, requires coagulation and flocculation before the sedimentation process.