Cyanobacteria and cyanotoxins in drinking water: Strategies for multi-barrier management and advancement in photocatalytic treatment

Cyanobacterial blooms and cyanotoxins present a significant threat to freshwater ecosystems and drinking water safety worldwide. Preventing bloom proliferation at the source and employing effective treatment within the water facility are essential for maintaining safe drinking water. Moderate pre-oxidation to enhance coagulation has emerged as a promising strategy that preserves cyanobacterial cell integrity, prevents the release of intracellular toxins, and reduces coagulant demand. Among advanced oxidation processes, photocatalysis has been extensively studied for the inactivation of cyanobacterial cells and the degradation of cyanotoxins. However, most studies have focused on excessive oxidation, with little attention to a moderate pre-photocatalytic treatment approach to enhance coagulation efficiency. Thus, this review comprehensively analyses various photocatalysts for managing cyanobacteria and cyanotoxins in drinking water, by systematically summarising and critically discussing their mechanisms, performance, limitations, and potential integration with conventional treatment processes. The review also highlights the research gap associated with moderate pre-photocatalysis approaches and emphasizes the need for further research to develop sustainable water treatment methods for the safe drinking water provision.