Microalgae Harvesting from Wastewater by Electroflocculation: Source for Biofuel Production

Objective: Third generation biorefineries based on microalgae biomass seem to be a great potential to supply future fuel consumption. However, technological challenges must be faced; such as microalgae harvesting, which is one of the most important bottlenecks. Several technics have been proposed to harvest microalgae such as centrifugation, flotation, precipitation, among others. However, some of them have economical, technical or environmental limitations. In this work, electroflocculation is examined to harvest microalgae using wastewater as growth media. Methods: The best conditions for current intensity, potential, electrodes material, electrolyte and resident time were determined by cyclic voltamperometry, for batch and continuous flow regimens. Results: Through the results of the analysis, the anodic and cathodic reactions were determined and the electroflocculation process performance has been explained. It was observed that oxygen release from the anode contributes significantly to microalgae separation process. Conclusion: Based on these results, it can be established that electroflocculation has a great potential, from a technical and economical point of view, to harvest microalgae.