Continuous electrocoagulation of Chlorella vulgaris in a novel channel-flow reactor: A pilot-scale harvesting study. (May 2022)

• Record Type: Journal Article
• Authors: Lucakova, Simona; Branyikova, Irena; Kovacikova, Sara; Masojidek, Jiri; Ranglova, Karolina; Branyik, Tomas; Ruzicka, Marek C.
• Is Part Of: Bioresource technology. Volume 351(2022)
• Publication Date: 2022-05
• Subjects: Electrocoagulation -- Electroflocculation -- Chlorella -- Microalgae -- Biomass harvesting; Biomass -- Periodicals; Biomass energy -- Periodicals; Bioremediation -- Periodicals; Agricultural wastes -- Periodicals; Factory and trade waste -- Periodicals; Organic wastes -- Periodicals; Bioénergie -- Périodiques; Déchets agricoles -- Périodiques; Déchets industriels -- Périodiques; Déchets organiques -- Périodiques; Déchets (Combustible) -- Périodiques; 662.88
• DOI: 10.1016/j.biortech.2022.126996
• Languages: English
• ISSNs: 0960-8524

Abstract

Graphical abstract: Highlights: Novel continuous electrocoagulation reactor was developed, capacity 240 L/h. Chlorella biomass harvesting efficiency was higher than 85 %. Harvested biomass was suitable for human consumption, Fe content below 4 mg/g. Power consumption was reduced by 80 % compared to centrifugation alone. Abstract: The most frequently used method to harvest microalgae on an industrial scale is centrifugation, although this has very high energy costs. To reduce these costs, a continuous electrocoagulation process for harvesting Chlorella vulgaris was developed and tested using a pilot-scale 111 L working volume device consisting of an electrolyser with iron electrodes, aggregation channel and lamellar settler. The flow rate of the microalgal suspension through the device was 240 L/h. When using controlled cultivation and subsequent electrocoagulation, a high harvesting efficiency (above 85%), a low Fe contamination in the harvested biomass (<4 mg Fe/g dry biomass, a harvested biomass complied with legislative requirements for food) and significant energy savings were achieved. When comparing electrocoagulation and subsequent centrifugation with the use of centrifugation alone, energy savings were 80 % for a biomass harvesting concentration of 0.23 g/L. Electrocoagulation was thus proven to be a feasible pre-concentration method for harvesting microalgae.