This study examined how ozone and permanganate preoxidation affect flocculation of Chodatella sp. cultures. Ozone caused cells release of extracellular organic matter (EOM) into the bulk water and altered the cell wall structure, detrimentally affecting algae flocculation. However, permanganate stressed cells, causing them to secrete EOM on cell surfaces, which can improve the absorbability of MnO2 during algae flocculation. In the presence of calcium, algae flocculation after permanganate preoxidation was appreciably increased due to Ca2 + functioning as a bridging agent between MnO2 and EOM. Algae flocculation was not enhanced in the presence of calcium after ozone preoxidation.
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