Gas sparged cross-flow microfiltration of biologically treated wastewater

A novel technique was tested for reducing tubular mineral membrane fouling by injecting gas into a cross-flow stream. The injected gas is thought to f orm complex hydrodynamic conditions inside the microfiltration module, whic h increase the wall shear stress, preventing the membrane fouling and enhan cing the microfiltration mass transfer. The experimental study was carried gut with biologically treated wastewater filtered through a tubular inorgan ic membrane (Carbosep M14). The flux, monotonously increasing with gas velo city, was more than tripled. New dimensionless quantities of shear stress n umber and resistance number were developed by generalisation of the dimensi onal analysis already carried out for the steady state flux of classical un sparged cross-flow filtration. A unique formalism allowed then interpreting the experimental results of both classical diphasic filtration and sparged filtration. The main limiting mass transport process was due to the solid content.