In situ H2O2 treatment of blue-green algae contaminated reservoirs causes significant improvement in drinking water treatability

• Published in: Chemosphere (Oxford) 2023-08, Vol.333, p.138895-138895, Article 138895
• Main Authors: Melo Rocha, Maria Aparecida, Clemente, Allan, Amorim Santos, Allan, da Silva Melo, Jessica, J. Pestana, Carlos, A. Lawton, Linda, Capelo-Neto, José
• Format: Article
• Language: English
• Subjects: Cyanobacteria; Exploratory factor analysis; In-reservoir treatment; Water treatment
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2023.138895

The evaluation of water quality improvement brought about by in situ treatment of eutrophic water bodies, especially those used for human supply is a challenging task since each water system responds differently. To overcome this challenge, we applied exploratory factor analysis (EFA) to understand the effects of using hydrogen peroxide (H2O2) on eutrophic water used as a drinking water supply. This analysis was used to identify the main factors that described the water treatability after exposing blue-green algae (cyanobacteria) contaminated raw water to H2O2 at both 5 and 10 mg L−1. Cyanobacterial chlorophyll-a was undetectable following the application of both concentrations of H2O2 after four days, while not causing relevant changes to green algae and diatoms chlorophyll-a concentrations. EFA demonstrated that the main factors affected by both H2O2 concentrations were turbidity, pH, and cyanobacterial chlorophyll-a concentration, which are important variables for a drinking water treatment plant. The H2O2 caused significant improvement in water treatability by decreasing those three variables. Finally, the use of EFA was demonstrated to be a promising tool in identifying which limnological variables are most relevant concerning the efficacy of water treatment, which in turn can make water quality monitoring more efficient and less costly. [Display omitted] •H2O2 improved water treatability by reducing turbidity, pH, and cyanobacterial chlorophyll-a concentration.•Exploratory factor analysis (EFA) can be applied to elucidate the individual characteristics of a given reservoir.•EFAs are able to indicate which variables are important to monitor to determine the effectiveness of in situ treatment.•EFA is a useful tool for monitoring the effects of water treatment.