Removal of algae from biological cultures: a challenge for electrocoagulation?

Abstract

AbstractBACKGROUNDIn the search for novel technologies for the treatment of urban wastewater, combined anaerobic–algae membrane bioreactors have become a very interesting choice. Recovery of algae produced in these reactors has become the key point to obtain a good economic efficiency with this technology. In this work, electrocoagulation is studied as an alternative for the coarse removal of algae from a biological culture.RESULTSResults demonstrate that the electrochemical technology is a suitable technology for this purpose allowing the removal of more than 90% of the algae without modifying significantly the pH and with an operating cost below 0.04 € m−3. The same general trends are observed for applied current charge and current density supplied when aluminum or iron are used as electrodes although aluminum was much more efficient.CONCLUSIONSThe dose of coagulant reagents required is very low, indicating that coagulant generated in the process is very efficiently used. The best results in terms of algae and turbidity removals are obtained operating at low current densities with aluminum electrodes. According to pH and z‐potential values, insoluble metal hydroxide and anion M(OH)4− seems to be the primary coagulation species involved in the electrocoagulation process. © 2014 Society of Chemical Industry