Environmental assessment for desalination projects including microbial desalination cells

Abstract

For MIDES it was necessary to analyse the aspects that should be considered for the environmental assessment of desalination projects that integrate the microbial desalination cells as pre-treatment for reverse osmosis. The approach used to that end was to combine three methods: revision of existing guidance for environmental and social assessment of desalination projects to compile a list of components and impacts; life cycle analysis based on a pre-pilot MDC to determine impacts associated with its construction and operation; and risk assessment to determine risks of the potential release of nanoparticles. The results showed that, at project level, existing guidance needs to pay more attention to the effects that the local and regional environment could have on a desalination project and to the regional cumulative effects to which a project could contribute. At the level of the MDC, the main impacts were the contribution to climate change and toxicity resulting from the 20:1 ratio of catholyte to feed water; however, preliminary data for the operation of a pilot MDC showed a reduction to a 5:1 ratio, with largely reduced impacts. At the structural level, the risk assessment showed that the release of nanoparticles from the cathodes and membranes is negligible.