Characterization of microbial communities in water and biofilms along a large scale SWRO desalination facility: Site-specific prerequisite for biofouling treatments

Biofouling impacts seawater reverse osmosis (SWRO) desalination plants by hindering module performance, increasing energetic demands, and incurring further costs. Here we investigated the spatial-temporal dynamics of microbial communities along the feedwater, pretreatment, and reverse osmosis stages of a large-scale SWRO desalination facility. While the composition of water-based microbial communities varied seasonally, the composition of biofilm microbial communities clustered by locations. Proteobacteria dominated throughout the water and biofilm communities while other dominant phyla varied seasonally and spatially. The microbial community composition significantly differed along the pathway locations of feedwater, rapid sand filtration (RSF), cartridge filters (CF), and the reverse osmosis (RO) membranes. Biofilms on the RSF and CF were composed of more diverse microbial populations than RO biofilms as determined by the effective number of species. Biofilms that developed along the treatment pathway (CF) served as inocula enhancing biofouling downstream on the RO membranes. Subsequently, we believe that prior to the development of advanced antibiofouling treatments for the desalination industries, the site-specific microbial community of feedwater, pretreatment and RO biofouling should be characterized. Site specific identification of these communities will enable optimization of pretreatment and cleaning procedures and can ultimately reduce chemical usage and incurred costs.