title: Synergy of flocculation and flotation for microalgae harvesting using aluminium electrolysis.
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.
authors.affiliation: CEER, Nanjing Hydraulics Research Institute, Guangzhoulu 223, Nanjing 210029, China.
authors.forename: Wenqing
authors.initials: W
authors.lastname: Shi
authors.affiliation: NIGLAS, Chinese Academy of Sciences, Beijingdonglu 73, Nanjing 210008, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Zhu
authors.affiliation: CEER, Nanjing Hydraulics Research Institute, Guangzhoulu 223, Nanjing 210029, China. Electronic address: qwchen@nhri.cn.
authors.forename: Qiuwen
authors.initials: Q
authors.lastname: Chen
authors.affiliation: Huaneng Lancang River Hydropower Co., Ltd., Shijichengzhonglu 1, Kunming 650214, China.
authors.forename: Ji
authors.initials: J
authors.lastname: Lu
authors.affiliation: RCEES, Chinese Academy of Sciences, Shuangqinglu 18, Beijing 100085, China.
authors.forename: Gang
authors.initials: G
authors.lastname: Pan
authors.affiliation: CEER, Nanjing Hydraulics Research Institute, Guangzhoulu 223, Nanjing 210029, China.
authors.forename: Liuming
authors.initials: L
authors.lastname: Hu
authors.affiliation: CEER, Nanjing Hydraulics Research Institute, Guangzhoulu 223, Nanjing 210029, China.
authors.forename: Qitao
authors.initials: Q
authors.lastname: Yi
mesh_terms: D000535:Aluminum; D018533:Biomass; D048408:Chlorella vulgaris; D004572:Electrolysis; D005427:Flocculation; D058086:Microalgae
chemical_list: D000535:Aluminum
keywords: Current density; Electro-flocculation; Energy consumption; Microalgae harvesting; Phosphate