The flocculation and sedimentation method could be used to the water treatment with a large number
of suspended solids and algae, which was simple to operate, easy to maintain and effective to treat,
however, the infrastructure costs and pharmacy costs were high, meanwhile, it was associated with
secondary pollution. Therefore, it cooperated with other processes as a pretreatment process. The
flocculation foam separation of poly aluminum chloride (PAC) and casein was non-polluting, which was
for recovery and removal of algae, and the best agent injection conditions were that the concentration of
PAC was 5mg/L, the time of rapid mixing was 3min, the concentration of casein was 15mg/L, and pH=7-
8 [9].