Industrial-scale microalgae pond primary dewatering chemistry for Energy-efficient autoflocculation

Brady, P.V., McHenry, M.P., Carolina Cuello, M. and Moheimani, N.R.ORCID: 0000-0003-2310-4147 (2015) Industrial-scale microalgae pond primary dewatering chemistry for Energy-efficient autoflocculation. In: Moheimani, N.R., McHenry, M.P., de Boer, K. and Bahri, P.A., (eds.) Biomass and Biofuels from Microalgae. Springer International Publishing, pp. 275-287.

Abstract

Industrial-scale microalgae production will likely require large energy-intensive technologies for both culture and biomass recovery; energy-efficient and cost-effective microalgae dewatering and water management are major challenges. Primary dewatering is typically achieved through flocculation followed by separation via settling or flotation. Flocculants are relatively expensive, and their presence can limit the reuse of de-oiled flocculated microalgae. Natural flocculation of microalgae—autoflocculation—occurs in response to changes in pH and water hardness and, if controlled, might lead to less-expensive “flocculant-free” dewatering. A better understanding of autoflocculation should also prompt higher yields by preventing unwanted autoflocculation. Autoflocculation is driven by double-layer coordination between microalgae, Ca+2 and Mg+2, and/or mineral surface precipitates of calcite, Mg(OH)2, and hydroxyapatite that form primarily at pH > 8. Combining surface complexation models that describe the interface of microalgae:water, calcite:water, Mg(OH)2:water, and hydroxyapatite:water allows optimal autoflocculation conditions—for example pH, Mg, Ca, and P levels—to be identified for a given culture medium.

Item Type:	Book Chapter
Murdoch Affiliation:	School of Engineering and Information Technology School of Veterinary and Life Sciences
Publisher:	Springer International Publishing
Copyright:	2015 Springer International Publishing Switzerland
Other Information:	Series Title: Biofuel and Biorefinery Technologies; Vol. 2
URI:	http://researchrepository.murdoch.edu.au/id/eprint/31970

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