The Application of Potassium Permanganate to Treat Cyanobacteria-Laden Water: a Review

Climate change and eutrophication provide favorable conditions for cyanobacterial growth which can lead to harmful algal blooms (HABs). HABs pose a threat to society due to the release of algal metabolites. Water utilities are challenged with treating cyanobacteria-laden water to effectively eliminate cyanotoxins while avoiding the negative impacts of taste and odor causing compounds, disinfection byproduct (DBP) formation, and increased organic matter loading caused by HABs. Historically, potassium permanganate (KMnO4) has been used for various applications in water treatment due to its affordability and easy implementation, but more recently, KMnO4 gained attention for its potential application to treat cyanobacterial cells. Accordingly, this review aims to summarize the current understanding of the application of KMnO4 as a pre-oxidant for the treatment of HAB impacted water. In this review, we discussed the impacts of KMnO4 on cyanobacterial cell and associated cyanotoxin removal, altering DBP formation, and reducing production of taste and odor causing compounds to highlight the potential application of KMnO4 for HAB treatment. Additionally, we summarized the adverse effects of using KMnO4, gave recommendations to minimize those impacts, and identified future research needs from multiple perspectives. Overall, this review provides a comprehensive current understanding, future directions and insights into the application of KMnO4 to address HABs related issues.