Microcystis aeruginosa-laden water treatment using peroxymonosulfate enhanced Fe(II) coagulation: Performance and the role of in situ formed Fe3O4

In order to eliminate the harm of the algal blooms to the safety of the drinking water production, Fe(II)/peroxymonosulfate (PMS) process was applied as simultaneous oxidation coupled with coagulation to enhance the removal of Microcystis aeruginosa (M. aeruginosa). In comparison with Fe(II)/H2O2 and Fe(II)/persulfate process, the higher removal rate of algae cells and faster settling speed were obtained in Fe(II)/PMS treatment. The removal rate of optical density at 680 nm (OD680), turbidity and dissolved organic carbon (DOC) reached up to 92.3%, 91.1% and 58.3% with the sequential addition of 90 μM Fe(II) and 50 μM PMS in 20 min. The moderate oxidation capacity of PMS in weak alkaline environment lead to the low ratios of damaged cells and algal organic matters (AOMs) release. The aggregation of the in situ formed Fe3O4 could significantly promote the generation and settleability of larger flocs. This study demonstrated that Fe(II)/PMS process might be a promising technology towards algae-laden water treatment.