Engineered osmosis – sustainable technology for water recovery, product concentration and energy generation

Abstract

Engineered osmosis (EO) holds a vast untapped potential to be commercially exploited for various applications, including water recovery, product concentration, and energy generation. The EO process is a sustainable membrane-based technology that operates on the natural osmotic gradient to drive water from the feed stream (low concentration) to a draw solution (high concentration). The EO has gained significant interest owing to the lower energy requirement, ability to handle challenging (high total dissolved solids) feeds, lower membrane fouling, and ease of integration with existing processes. This review includes an extensive compilation of the latest developments (2018–2021) in the applications of the forward osmosis (FO) technology, and provides a critical analysis of the membrane development, synthesis/identification of novel draw solutes (DS), draw solute recovery/regeneration, process integration, utilizing renewable energy, the effect of foulants, the efficacy of cleaning protocols, etc. A dedicated section on energy generation by pressure retarded osmosis includes membrane development, energy considerations, and process integrations. The technical challenges and feasibility of adopting the EO technology are also discussed.