Algae in surface water have been a long-term issue all over the world, due to their adverse influence on drinking water treatment process as well as drinking water quality. The algae removal by
electro-coagulation–flotation (ECF) technology was investigated in this paper. The results indicated that
aluminum was an excellent electrode material for algae removal as compared with iron. The optimal
parameters determined were: current density=1mA/cm2, pH=4–7, water temperature=18–36 ◦C, algae
density=0.55 × 109–1.55 × 109 cells/L.Undertheoptimalconditions,100%ofalgaeremovalwasachieved
with the energy consumption as low as 0.4kWh/m3. The ECF performed well in acid and neutral conditions. At low initial pH of 4–7, the cell density of algae was effectively removed in the ECF, mainly through
the charge neutralization mechanism; while the algae removal worsened when the pH increased (7–10),
and the main mechanism shifted to sweeping flocculation and enmeshment. The mechanisms for algae
removal at different pH were also confirmed by atomic force microscopy (AFM) analysis. Furthermore,
initialcelldensityandwatertemperaturecouldalsoinfluencethealgaeremoval.Overall,theresultsindicated that the ECF technology was effective for algae removal, from both the technical and economical
points of view.