Removal of Microcystis aeruginosa and control of algal organic matter by Fe(II)/peroxymonosulfate pre-oxidation enhanced coagulation

Fe(II)/Peroxymonosulfate (PMS) pre-oxidation enhanced coagulation was investigated to remove Microcystis aeruginosa (M. aeruginosa) in this study. When the initial algae cell concentration was 1.0 x 10(6) cells/mL, the highest removal efficiency of algae cells (94.3%) was achieved with lower chemical dosage (e.g. 20 mg/L PMS and 4.5 mg/L Fe(II)). During the pre-oxidation, the release of K+ and death rate of algae cells were lower, meanwhile, relative intact cellular structure was remained. Sulfate radical (SO4 center dot-) was the predominant radical species to facilitate algae removal by decreasing zeta potential in the Fe(II)/PMS system. The majority of algal organic matter (more than 83% of proteins and 76% of polysaccharides) was eliminated after coagulation and sedimentation, indicating that the potential of disinfection by products (DBPs) formation was decreased. Furthermore, Fe(II)/PMS process was optimized by response surface methodology (RSM) according to central composite design (CCD), the higher removal efficiency of M. aeruginosa with lower reagent cost under optimal conditions were obtained. This study provides a promising method of eliminating M. aeruginosa and controlling algal organic matter effectively in eutrophic water.