According to the algae outbreak (the dominant species was synedra acus belonging to Diatoms) in source water

the effects of PAFS

PAC

and PFC coagulants on algae removal and turbidity removal were compared. PAFS was chosen as the optimal coagulant. In addition

different pro-oxidations and coagulant aids were added to enhance flocculation removal effects of algae. The experimental results show that PDMDAAC combined with PAFC shows the best effect

and the order of other promoting coagulation effect was PPC>ClO2>PAM>H2O2>HCA-1. Based on the box-Behnken Design(BBD) experiment design principle

the effects of pH

stirring rate and stirring time on algae removal using PAFS+PDMDAAC were investigated. The results show that the three factors play significant effect on the removal of synedra acus

and the influence degree is pH>stirring rate>stirring time

while the interactive influence of the three factors is not significant. Moreover

the optimum condition of enhanced coagulation is obtained

in which pH is of 7.5

stirring rate is 75r/min and stirring time is 15 min

and the alga removal effect is 98.75%.