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

Abstract

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.