Performance optimization of a 5 nm TiO2 ceramic membrane with respect to beverage production wastewater Original Research Article

A 5 nm TiO2 ceramic ultrafiltration membrane was evaluated with respect to beverage production wastewater. The influence of operating parameters such as crossflow velocity (CFV), transmembrane pressure (TMP) and particle size distribution on filtration performance was investigated. Results show that certain combinations of higher CFVs and TMPs provide significant improvements in permeate flux and contaminant rejection rates. These improvements are attributed to the turbulent flow regime experienced by suspended particles during ultrafiltration. At higher CFVs of 3.1 and 3.6 m s− 1, the majority of the particles present in the wastewater are swept away from the membrane surface resulting in reduced concentration polarization (cake layer) resistance and improved permeate flux. The steady-state permeate fluxes measured at CFVs of 3.1 and 3.6 m s− 1 increased by 22% and 53% respectively when TMP was increased to 200 kPa. Increasing the TMP further to 300 kPa also increased the steady-state permeate fluxes by 16% and 4% respectively. Similarly, the reduction in concentration polarization resistances at these CFVs also reduced particle infiltration into the membrane pores resulting in better filtrate quality in terms of turbidity and COD. A CFV of 3.1 m s− 1 and a TMP of 300 kPa were identified as optimal operating conditions in terms of energy consumption and permeate flow rate.