Life cycle assessment of hybrid electrodialysis and reverse osmosis seawater desalination systems

Abstract

This study investigates the environmental impact (EI) and water footprint (WF) of four seawater (SW) desalination configurations that combine both standalone and hybrid systems of SW reverse osmosis (SWRO) and SW electrodialysis (SWED). The analysis is conducted using life cycle assessment (LCA) and water recovery calculations. The results indicate that the hybrid SWRO-ED configuration has increased water recovery by 18–48 % over standalone SWRO and SWED. However, the SWRO-ED hybrid configuration has decreased membrane performance, which leads to increasing membrane replacement by 1.2–3.7 times compared to standalones SWED and SWRO, respectively. The carbon footprint for the SWRO-ED hybridization is 7.62 kg CO2 eq. per cubic meter of desalinated water compared to 5.35 and 6.48 kg CO2 eq/m3 emitted from SWRO and SWED standalones, respectively. On the other hand, the amending of SWED with brackish water RO (BWRO) consecutively increases water recovery by 8.4–42.1 % while reducing CO2 emissions by 41–51 %. The average WF per cubic meter of desalinated water is 2.46, 3.52, 2.65 and 3.92 m3 for the SWRO standalone, SWED standalone, SWED-BWRO, and SWRO-ED hybrid systems, respectively. Most of the WF is consumed indirectly for electricity or chemical production required for water desalination.