Effect of pH on inactivation of Microcystis aeruginosa by ozonation air in sequencing batch reactor

In this study, a mixture of ozone and air (ozonation air for short) was adopted for the inactivation of Microcystis aeruginosa in a sequencing batch reactor (SBR). Scanning electron microscopy of Microcysti s aeruginosa revealed damage to the cell wall and leakage of intracellular contents after ozone oxidation. Owing to the destruction of cells, the chlorophyll a released from the cells was degraded by ozone oxidation, which showed that chlorophyll a concentrations increased vastly during the first 5 min, then, decreased continuously. pH in the SBR declined with increasing time, reaching around 3.0 at the end of the cycle. It was observed that the removal efficiencies of chlorophyll a were, respectively, 68.4%, 74.5%, 86.7% and 77.9% after 90 min at pH 3.0, 7.0, 9.0 and 11.0 conditions, and the degradation of chlorophyll a accorded with the apparent first‐order kinetics. The results suggested that inactivation of Microcysti s aeruginosa was successfully performed by ozone treatment, verifying the potential of this alternative process for the decontamination of eutrophic water. Copyright © 2010 Society of Chemical Industry