Optimization of electrocoagulation-flotation treatment with an aluminum anode to enhance Microcystis aeruginosa cell removal efficiency

Cyanobacteria adversely affect drinking water treatment and the quality of the drinking water supply. Microcystis spp. are the most abundant cyanobacteria in many surface water bodies throughout the world. Electrocoagulation-flotation (ECF) treatment has attracted considerable attention as a means of cyanobacteria removal. In this study, ECF treatment was optimized by adjusting the initial pH, electrode distance, stirring speed, and electrical conductivity (k) to maximize Microcystis aeruginosa cell removal efficiency while meeting drinking water quality standards. The treatment was performed for 200 mL M. aeruginosa suspensions (-2 x 10(6) cells/mL) using an aluminum anode and a graphite cathode at a constant direct current of 100 mA. An initial pH of 6, a stirring speed of 200 rpm, an electrode distance of 1 cm, and k of 500 mu S/cm were selected as optimum conditions for the ECF treatment. Under these conditions, M. aeruginosa at a cell density of -2 x 10(6) cells/mL was completely removed at a current density of 4.0 mA/cm(2) with an average energy consumption of 1.20 +/- 0.03 Wh/L. The zeta potential varied from-18.49 +/- 3 mV to 1.15 +/- 0.38 mV, which confirmed the complete removal of cells. Most importantly, the pH, aluminum concentration, and total dissolved solids of the treated water met the drinking water quality standards of the World Health Organization. The optimized ECF treatment was thus shown to be promising for the removal of M. aeruginosa cells.

Automated summary

In this study, ECF treatment was optimized to efficiently remove Microcystis aeruginosa cells while meeting drinking water quality standards. The optimized ECF treatment showed promising results for the removal of Microcystis aeruginosa cells.