Living Filtration Membranes Demonstrate Antibiofouling Properties

Abstract

Membrane filters are excellent prospects for increasing global access to safe water; however, they are significantly limited by fouling, particularly biofouling. Fouling plagues membranes by reducing efficiency and increasing maintenance and costs. Biofouling is particularly problematic due to the self-replicating nature of microorganisms and the secretion of extracellular polymeric substances that make the biofilm difficult to remove. Living filtration membranes (LFMs) are a sustainable membrane technology composed of bacterial cellulose and native microorganisms. In this study, natural water from Butte, Montana's three municipal drinking water sources (Basin Creek Reservoir, Moulton Reservoir, and Big Hole River) was pretreated with a coagulant and used in 400 min bench-scale dead-end filtration tests. Two membranes were compared─an LFM and a commercial mixed cellulose ester (MCE) membrane with a similar nominal pore size. Although the MCE membrane was more hydrophilic and had a smoother surface, surface properties that, in general, may improve fouling resistance for certain particles, a more rapid flux decline and live biomass were observed with the MCE membrane for all three waters. We suggest that the LFM's resistance to biofouling may be due to the proliferation of native bacteria, Acetobacter, which produces acetic acid, a known antibiofilm and antibacterial agent.