Living Filtration Membranes (LFMs) are a water filtration technology that was recently developed in the lab (Technology Readiness Level 4). LFMs have shown filtration performance comparable with that of ultrafiltration, far better fouling resistance than conventional polymer membranes, and good healing capabilities. These properties give LFMs promise to address two significant issues in conventional membrane filtrationfouling and membrane damage. To integrate environmental considerations into future technology development (i.e., Ecodesign), this study assesses the life cycle environmental performance of LFMs treating drinking water under likely design and operation conditions. It also quantitatively ranks the engineering design and operation factors governing the further optimization of LFMs' environmental performance using a global sensitivity analysis. The results suggest that LFMs' superior fouling resistance will reduce the life cycle environmental impacts of ultrafiltration by 25% compared to a conventional polymer membrane in most impact categories (e.g., Acidification, Global Warming Potential and Carcinogenics). The only exception is the eutrophication impacts, where the need for growth medium and membrane regeneration offsets the benefits of LFMs' fouling resistance. Permeability is the most important factor that should be prioritized in future R&D to further improve LFMs' life cycle environmental performance. A 1% improvement in the permeability will lead to a ~0.7% improvement in LFMs' environmental performance in all the impact categories, whereas the same change in the other parameters investigated (e.g. LFM lifespan and regeneration frequency) typically only leads to a <0.2% improvement.

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.