OPTIMIZATION OF BASIC WATER-TREATMENT PROCESSES - DESIGN AND OPERATION - COAGULATION AND FLOCCULATION

The coagulation and flocculation processes are extremely important pre -treatments for conventional rapid sand filtration as well as modern h igh-rate filtration processes. Proper destabilisation of colloidal sub stances in raw water and enmeshment of these substances into flee by c oagulation and flocculation are necessary for subsequent clarification and filtration. Inadequate pre-treatment results in poor filter effic iency; even with a conservative filtration rate, serious consequences may result. This paper describes some important processes including ch emical applications, a jar test method, and concerns over an on/off ty pe of plant operation.