Algae removal performance of UV-radiation-enhanced coagulation for two representative algal species

Abstract Algal blooms severely impact the ecological environment and human health, as well as drinking water supplies and treatment systems. This study investigated UV-radiation-enhanced aluminum (Al)-based coagulation for the removal of two representative algal species (Microcystis aeruginosa and Cyclotella sp.) which are responsible for most fresh water algal bloom in different seasons. The results demonstrated that the UV-Al process can enhance algae removal, and simultaneously control algal organic matter (AOM) release. Comparing with Microcystis aeruginosa, Cyclotella sp. was more sensitive to UV irradiation and its activity was severely inhibited by 240 s of UV irradiation; intracellular reactive oxygen species (ROS) increased sharply then decreased rapidly, and SEM images showed cell walls exhibited substantial compression. UV irradiation decreased the zeta potential, which might have contributed to algae removal. Approximately 93.5% of Microcystis aeruginosa cells and 91.4% of Cyclotella sp. cells were removed after 240 s of UV irradiation with 0.4 mmol/L Al. The MCs concentrations after Al coagulation were low (