Resource recovery with microbial electrochemical systems

Yu, EH

doi:10.1016/B978-1-78242-375-1.00010-1

Resource recovery with microbial electrochemical systems

Lookup NU author(s): Professor Eileen Yu

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Abstract

© 2016 Elsevier Ltd. All rights reserved. Microbial electrochemical systems consist of microbial fuel cells (MFCs), microbial electrolysis cells, and microbial desalination cells. They use an anode immobilized with microorganisms to oxidize organic matters in the wastewater and produce electrons. As the energy generation from MFCs is limited, more and more attention has been directed to reducing energy demand for wastewater treatment, and using cathode reactions, anoxic or aerobic, for recovering resources from waste.In this chapter, single and mixed metal ions recovery from various sources and concentrations using abiotic and biocathode in a bioelectrochemical system (BES) has been reviewed. Simultaneous metal recovery and electric energy generation was possible for the metals with more positive reduction potential than copper (0.34V, standard hydrogen electrode). Electrodeposition electroprecipitation and biosorption are the main mechanisms for metal removal and recovery. Nutrients, mainly nitrogen and phosphorous, removal and recovery have been discussed. Nitrogen recovery is mainly in the form of ammonia recovery, whereas phosphorous recovery is by forming struvite precipitation (MgNH4PO4·6H2O) by adding magnesium and ammonia at the cathode of BES.Electrochemical reduction of CO2 to produce various simple organic compounds is largely dependent on the catalysts chosen. With electrons/electric energy produced from microbial anode in BES, the overall energy for CO2 reduction can be reduced. Microbial electrosynthesis opens up a new avenue on synthesizing medium chain organic compounds with chain elongation process.BES combining waste treatment and extracting energy and recovering resources from waste is a promising technology for sustainable chemical and fuel production, and will have positive impact on the environment and society.