Identification of bacterial biofilms on desalination reverse osmosis membranes from the mediterranean sea

Nanofiltration and reverse osmosis are two of the most effective surface water treatment processes. They provide water of high quality and eliminate a large amount of microorganisms, organic matter and micropollutants. However, the main limitation of membrane nanofiltration is fouling, which imposes an additional cost. This study focused on the search for microorganisms capable of reducing the performance of nanofilters and also to study autoaggregation and biofilms formation by bacterial strains isolated from the nanomembranes used in the seawater desalination plant of Souk Tlata (Algeria). It provides new microbiological data on the desalination of seawater in the southern Mediterranean basin. The results revealed 14 bacterial species isolated from six fouled reverse osmosis membranes; their quantities were significant with the dominance of Raoultella sp., Klebsiella sp., Staphylococcus sp., Stenotrophomonas sp., Micrococcus sp., and Escherichia coli. In addition, electron imaging of nanomembrane surfaces revealed complex structures of microorganisms forming biofilms.