Effects of suspended titanium dioxide (TiO2) nanoparticles on cake layer formation in submerged anaerobic membrane bioreactor (AnMBR) for landfill leachate treatment (LFL)

In recent years, TiO₂ NPs have attracted great attention among the semiconductors because of stability, commercial availability, and ease of preparation. For this reason, NPs are widely used in wastewater treatment and membrane bioreactor (MBRs) In this study, the effect of titanium dioxide (TiO2) nanoparticle material was investigated on both the landfill leachate (LFL) treatment and membrane fouling performance. The system performance was evaluated for under varying TiO₂ concentrations (50–300 mg/L TiO₂), constant HRT (24 h), and constant backwashing (5 min)-relaxing (0.5 min) in AnMBR. The optimum conditions were determined as 300 mg/L TiO₂ and the corresponding to COD, Color, TOC and TN removal efficiencies were observed as 55 %, 23 %, 22 %, 30 %, respectively. The best membrane performance was observed at 300 mg/L TiO₂ corresponding to membrane fouling rate as 0.01 mbar/min. TiO₂ addition significantly mitigated membrane fouling (75 % decrease) for AnMBR. Bacteroidetes, Firmicutes and Proteobacteria have been observed to be the dominant species in LFL and MBRs. The bacterial species responsible for membrane fouling were determined as Alphaproteobacteria, Sphingobacteria and Flavobacteria. The addition of TiO₂ was determined membrane fouling decreased in AnMBR. As a result of TiO₂ NPs were observed to thin the cake layer and postpone membrane fouling and filtration.