Removal of pathogenic microorganisms from water by electrocoagulation with aluminum electrodes

The electrocoagulation is considered as a technique with great potential to replace the conventional method of coagulation-flocculation induced by chemical reagents. Currently, this technique has been taken with interest in wastewater treatments in public services of water supplies, industries, and sanitation. Briefly, the electrocoagulation generates in-situ the metallic ions, which are the precursors of a broad range of coagulant species. The amount of generated ions is easily controlled with the time of electrolysis and the cell parameters set-up (e. g., potential or current). The coagulants will be composed by a variety of oligomeric species with different surface charges. These coagulants will destabilize and "catch" pathogenic microorganisms or colloidal particles from the wastewaters. Afterward, the excess of coagulants will entail the formation of precipitates (a.k.a. flocculation) which are easily removed by filtration. Herein, two different qualities of metallic aluminum were tested for the electrogeneration of coagulant species: a) aluminum obtained from soda drink cans, and b) pristine aluminum. The electrochemical characterization has shown that the aluminum coming from commercial soda drinks produces higher loads of coagulant agents than the pristine aluminum under the same experimental conditions. Hence, commercial aluminum was chosen as anodic material for the treatment of artificial waters infected with three types of bacteria: Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus, respectively. The experimental results have shown an effectiveness of the 100% on the removal of Pseudomonas aeruginosa and Escherichia coli, whereas for Staphylococcus aureus the removal efficiency was 99.86%.