Automatic microfiber filtration (AMF) of surface water: impact on water quality and biofouling evolution

In the current study we examined the impact of thread filtration using an automatic microfiber filter on Lake Kinneret water quality and as a new application to control biofouling over time. We found that automatic microfiber filtration (AMF) reduced total iron and aluminum in water by over 80%. Particle analysis (>2 μm) revealed a total particle removal efficiency of ≈ 90%, with AMF removal efficiency increasing with increasing particle size and decreasing particle circularity. Regarding microbiological parameters, AMF did not affect bacterial counts or composition in the water. However, it did control biofilm evolution and affected its microbial community composition. AMF controlled biofilm over time by maintaining premature biofilms of less than 10 μm mean thickness compared to biofilms of unfiltered water (up to 60 μm mean thickness). In addition, biofilms developing in AMF filtered water contained relatively low levels of extracellular polymeric substances. While biofilms of unfiltered water were dominated by Proteobacteria (≤ 50%) followed by Bacteroidetes (20-30%) during all 4 weeks of the experiment, biofilms of AMF filtered water were dominated by Proteobacteria (≤ 90%) and especially Alphaproteobacteria after 2 weeks, and Chloroflexi (≈ 60%) after 4 weeks. The decrease in Bacteroidetes might originate from removal of transparent exopolymer particles, which are occasionally colonized by Bacteroidetes. The increase in Alphaproteobacteria and Chloroflexi was explained by these robust groups' ability to adjust to different environments.