Insights into the underlying mechanisms for integrated inactivation of A. spiroides and depression of disinfection byproducts by plasma oxidation.

Cyanobacteria blooms threaten water supply and are potential sources for disinfection byproducts (DBPs) formation. In this study, the underlying mechanisms for effective removal of A. spiroides and the following depression on the formation of DBPs were disclosed. Highly efficient inactivation (more than 99.99%) of A. spiroides was realized by the plasma treatment within 12 min, and 93.4% of Anatoxin-a was also removed within 12 min, with no signals of resurrection after 7 days' re-cultivation. Transcriptomic analysis demonstrated that the expressions of the genes related to cell walls and peripherals, thylakoid membranes, photosynthetic membranes, and detoxification of toxins were distinctly altered. The generated reactive oxidative species (ROS), including ·OH, O, and O, attacked A. spiroides and resulted in membrane damage and algae organic matter (AOM) release. EEM-PARAFAC analysis illustrated that the AOM compositions were subsequently decomposed by the ROS. As a result, the formation potentials of the C-DBPs and N-DBPs were significantly inhibited, due to the effectively removal of AOM and Anatoxin-a. This study disclosed the underneath mechanisms for the effective inactivation of A. spiroides and inhibition of the following formation of the DBPs, and supplied a prospective technique for integrated pollutant control of cyanobacterial containing drinking water.