Forward osmosis as a platform for resource recovery from municipal wastewater - A critical assessment of the literature

Forward osmosis (FO) is an emerging membrane separation technology that has the potential to serve as a game changer in wastewater treatment. FO-based processes can simultaneously produce high quality effluent and pre-concentrated wastewater for anaerobic treatment to facilitate the recovery of energy and nutrients. Complex wastewaters can be directly pre-treated by FO and fresh water can be produced when coupled with a draw solute recovery process (i.e. reverse osmosis or membrane distillation). By enriching organic carbon and nutrients for subsequent biogas production, FO extends the resource recovery potential of current wastewater treatment processes. Here, we critically review recent applications of FO for simultaneous treatment and resource recovery from municipal wastewater. Research conducted to date highlights the importance of successfully integrating FO with anaerobic treatment. Emphasis is also placed on the development of novel FO-based hybrid systems utilising alternative energy sources for draw solute recovery. There remain several technical challenges to the practical realisation of FO for resource recovery from wastewater including salinity build-up, membrane fouling, and system scale-up. Strategies to overcome these challenges are critically assessed to establish a research roadmap for further development of FO as a platform for resource recovery from wastewater.