Synergy of flocculation and flotation for microalgae harvesting using aluminium electrolysis. (June 2017)

• Record Type: Journal Article
• Authors: Shi, Wenqing; Zhu, Lin; Chen, Qiuwen; Lu, Ji; Pan, Gang; Hu, Liuming; Yi, Qitao
• Is Part Of: Bioresource technology. Volume 233(2017)
• Page Start: 127
• Page End: 133
• Publication Date: 2017-06
• Subjects: Microalgae harvesting -- Electro-flocculation -- Current density -- Energy consumption -- Phosphate; 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.2017.02.084
• Languages: English
• ISSNs: 0960-8524

Abstract

Graphical abstract: Highlights: Electro-flocculation is a rapid and efficient way to harvest microalgae. Microalgae flocs formed in a snowballing style. Phosphate decrease benefits microalgae based wastewater treatment. Abstract: Microalgae are often used as feedstock for renewable biofuel production and as pollutant up-takers for wastewater treatment; however, biomass harvesting still remains a challenge in field applications. In this study, electro-flocculation using aluminium electrolysis was tested as a method to collect Chlorella vulgaris . The electrolysis products were positively charged over a wide pH range below 9.5, which gave them a flocculation potential for negatively charged microalgae. As flocculants were in-situ generated and gradually released, microalgae flocs formed in a snowballing mode, resulting in the compaction of large flocs. When higher current density was applied, microalgae could be harvested more rapidly, although there was a trade-off between a higher energy use and more residual aluminium in the culture medium. Benefits of this flocculation method are twofold: the phosphate decrease in post-harvesting could improve nutrient removal in microalgae based wastewater treatment, while the ammonium increase may favor microalgae recovery for medium recycling.