Enhanced filtration performance of biocarriers facilitated gravity-driven membrane (GDM) by vacuum ultraviolet (VUV) pretreatment: Membrane biofouling characteristics and bacterial investigation

Membrane biofouling is a challenge for biocarriers facilitated gravity-driven membrane (GDM) systems to achieve high-efficiency filtration in decentralized drinking water treatment. The purpose of this study was to investigate the effects of vacuum ultraviolet (VUV) as a pretreatment on membrane fouling, permeate water quality and bacterial communities. VUV pretreatment was found to significantly reduce the cake layer resistance by 24.4% and the membrane pore resistance by 40.0% (p < 0.05), resulting in a 22.2% increase in stable flux. The removal of low molecular weight neutrals and protein-like materials was enhanced by 22.5% and 40.1% respectively after VUV pretreatment. The heterogeneity of the biofouling layer was improved by VUV pre-treatment, and the porosity and roughness were increased by 227.5% and 46.5%, respectively. The application of VUV pretreatment resulted in a larger nanoparticle size in the biofouling layer suspension (peak at 85.4 nm), improvement in the membrane hydrophilicity, and a decrease in protein-like substances adhesion. The richness and diversity of the bacterial community were decreased by VUV pretreatment. The bacterial community structure had the highest mantel correlation with biopolymers (r = 0.89). Overall, VUV pretreatment can be a promising strategy to effectively alleviate membrane biofouling in biocarriers facilitated GDM systems.

Automated summary

The effects of vacuum ultraviolet (VUV) pretreatment on membrane fouling, permeate water quality, and bacterial communities were investigated in this study. The results showed that VUV pretreatment significantly reduced membrane resistance, increased stable flux, and improved the removal of pollutants. The pretreatment also enhanced the porosity and roughness of the membrane surface, decreased protein adhesion, and decreased the richness and diversity of bacterial communities.