Assessment of water quality variations on pretreatment and environmental impacts of SWRO desalination

Seawater reverse osmosis (SWRO) desalination is a widely adopted desalination technology given its cost effectiveness and lower energy consumption compared to thermal methods. However, SWRO is sensitive to intake water quality and requires strict pretreatment, which requires significant chemical inputs. This study evaluates the relative environmental impacts of water quality (site selection) and specific selection of chemicals on the overall environmental burden of the SWRO process. A life cycle assessment was carried out of environmental emissions based on an existing SWRO plant in the Arabian Gulf, which was remodelled and sized in AqMB® software based on different intake water quality gathered from seawater samples collected from 19 locations across 563 km of Arabian Gulf coastline. The study concluded that a total reduction of close to 25% in different environmental impacts was possible only by optimizing the location of plant, while careful selection of chemicals, particularly those in coagulation, disinfection and pH neutralization, could significantly influence environmental impact categories with high normalized impact such as marine ecotoxicity potential (MAETP). In comparison, renewable energy in the form of wind provided large reductions in certain significant impact categories, but provided a large increase in MAETP compared to natural gas.

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Published in: Desalination
License: http://creativecommons.org/licenses/by/4.0/
See article on publisher's website: https://dx.doi.org/10.1016/j.desal.2020.114831