Removal of Microcystis aeruginosa by potassium ferrate (VI): Impacts on cells integrity, intracellular organic matter release and disinfection by-products formation

Bench scale tests were conducted to study the effect of potassium ferrate (VI) on cell integrity, intracellular organic matter release and disinfection by-products formation of Microcystis aeruginosa. The simulated algal suspension was prepared a concentration of 1.0 × 106 cells/mL and the cytoplasmic membrane integrity was measured with flow cytometry. Results showed that a quick inactivation was achieved after ferrate (VI) oxidation, although no obvious cell lysis was observed. Intracellular organic matter (IOM) release increased with ferrate (VI) dosage and contributed to the formation of trihalomethanes (THM) and haloacetic acids (HAA) as chlorination by-products. However, enhanced coagulation of ferrate (VI) significantly removed M. aeruginosa cells and decreased the algal organic matters (AOMs). Furthermore, the concentrations of THM and HAA were reduced by 71.1% and 67.1%, respectively. Consequently, this study demonstrated potassium ferrate (VI) could act as a dual-functional chemical reagent (i.e., oxidant and coagulant) and may be potentially used in addressing the algal-rich drinking water.