Electrocoagulation reduces harvesting cost of microalgae

https://cesnet.zoom.us/j/92328512103

Photo-autotrophically produced microalgae, such as Chlorella vulgaris, are increasingly used in human and animal nutrition or as a source of bioactive substances in various fields. Their use in the field of so-called third-generation biofuels is also being considered, but this is hindered mainly by the high price of their biomass, which stems from the complexity of the production process, especially harvesting, which is usually done via centrifugation. The novel method consists of the addition of a pre-concentration step prior to the centrifugation. This pre-concentration is to be carried out by electrocoagulation.  We performed an extensive parametric study of the process of electrocoagulation of C. vulgaris in laboratory conditions, which should consequently serve for the proper design of the process on a larger scale. The influence of electric chargé per volume of suspension, initial biomass concentration, pH, temperature, stirring intensity, residual salt content in the culture medium, and electrolysis time was investigated. In a wide range of conditions, the separation efficiency was higher than 95%, and the total energy costs of separating algae from the medium were reduced by 84%.