Environmental and economic assessment of beach well intake versus open intake for seawater reverse osmosis desalination

Abstract

This paper presents a comparative life cycle assessment (LCA) and levelised cost (LC) analysis of two scenarios: an open intake scenario in which a seawater reverse osmosis (SWRO) desalination plant employs an open intake and membrane pre-treatment prior to RO, and a beach well scenario in which feedwater is extracted from the subsurface using beach well intake and cartridge filtration prior to RO. In both scenarios, desalination plants with 35,000m3/day capacities were modelled. Results indicate that the beach well intake plant life cycle environmental burdens and LC were as much as 31% and 13% lower respectively, compared with the open intake plant. A detailed contribution analysis revealed that the better environmental performance of the beach well intake plant was significantly influenced by its comparatively low electricity use in the simplified pre-treatment process. The better economic performance of the plant with beach well intake was mostly due to savings in chemical use. The results are based on site specific assumptions. However, the LCA and LC framework developed herein could be used to determine the optimum SWRO seawater intake and pre-treatment configuration at plant sites with different characteristics to those modelled herein, provided sufficient data is available.