Calcium peroxide (CaO2) granules enclosed in textile materials as H2O2 delivery systems to mitigate Microcystis sp. blooms

The past years, hydrogen peroxide (H₂O₂) has been introduced as an environmentally friendly method to combat in situ toxic cyanobacteria blooms because of its selective oxidation and zero waste production. Calcium peroxide (CaO₂)granules are an alternative to liquid H₂O₂ due to their slow H₂O₂ release properties. Herein, concentrations of 0.5, 1.0, and 2.0 g/L CaO₂ granules were (a) added into a surface water matrix to investigate their H₂O₂ releasing properties, (b) enclosed in four types of textile materials as delivery systems to evaluate their overall oxidant releasing capacity and (c) the best ones were applied on a dense Microcystis sp. bloom to investigate their potential to combat cyanobacteria. No difference was observed between the maximum H₂O₂ concentrations of the direct application of granules and the fabric delivery systems of types A – C, (released up to 12 mg/L H₂O₂ for 2.0 g/L CaO₂). Fabric system type D had the lowest H₂O₂ release (2.0 mg/L). Treatment experiments showed that delivery system B with 2 g/L granules and type C of 1 g/L and 2g/L were sufficient to significantly reduce the photosynthetic activity of Microcystis, proving that these delivery systems have the potential to become a more environmentally friendly alternative to H₂O₂.