Using Bioelectrochemical Systems for Sustainable Desalination

Abstract

Desalination of seawater or brackish water holds the potential to solve the freshwater shortage that is threatening nearly half of the world population. Current desalination technologies are energy intensive, which makes the desalinated water prohibitively expensive. In this study, investigations have been made to use renewable energy sources from organic waste to power the desalination process. Since desalination is driven by renewable energy, such desalination systems are more sustainable than currently wide employed commercial technologies. Efforts have been made to study how to operate BES driven desalination process such that the energy consumption will be minimized. Forward osmosis technology is also incorporated into BES system for desalination and water reclamation. Two types of FO-BES combined systems are studied here. In this first type, the FO was used as separator in Microbial Desalination Cell (MDC) to achieve the goals of desalination and water reclamation in a single BES. In the second type of system, the MDC was connected with an Osmotic Microbial Fuel Cell (OsMFC). The water reclamation is achieved in OsMFC while the task of desalination is left for MDC. A cost effective cathode catalyst is also prepared in order to lower the capital cost of BES for full scale application. The catalyst is based on activated carbon, which is relatively cheaper to noble metal catalysts, and can be prepared by using simple methods. The activated carbon based catalyst showed high catalytic activity toward oxygen reduction reaction and achieved higher current density than Pt based catalyst.