A surface treatment of two organo-selenium compounds was used to covalently coat reverse osmosis (RO) membranes. The organo-selenium compounds were tested for their ability to inhibit biomass formation at the membrane surface. The RO membranes were tested in a flow-cell apparatus that exposed the sample membranes to continuous flow for fourteen days. Membranes were exposed to a control media of Luria Bertani broth and a synthetic wastewater. The bacterial strains used in the experiments were: Escherichia coli, and Staphylococcus aureus. This research is an extension of the research presented by Low et al. in 2011, where organo-selenium was tested against S. aureus on a small scale. We obtained 2.01 and 2.61 logs of inhibition in the total specific biomass concentration (mu m(3)/mu m(2)) with synthetic wastewater, and 2.83 and 4.33 logs of inhibition with the LB broth medium. In addition, we observed a 2.64 and 2.67 log reduction in the average biofilm thickness (mu m) for synthetic wastewater medium, and 2.98 and 3.98 log reduction for the LB broth medium. These results suggest that the attachment of organo-selenium to the surface of RO membranes is a significant form of antibiofouling technology that is capable of high removal rates, and may be capable of reducing operating costs. (C) 2012 Elsevier B.V. All rights reserved.