Investigation of parameters affecting the ultrafiltration of oil-in-water emulsion wastewater

The ultrafiltration (UF) of model oily wastewater containing an emulsifier was investigated in order to determine the main parameters affecting the flux, retention and membrane fouling. The experiments were carried out with a laboratory UF device, using regenerated cellulose UF membranes. The finding that the fall in flux with time correlated best with the cake formation model is in accordance with the result that increasing resistance during filtration is caused predominantly by the concentration polarization, while the participation of membrane fouling in the total resistance is negligible. Analysis of the parameters affecting the UF of oily wastewater demonstrated that the flux is mainly influenced by temperature and concentration (besides the membrane pore size), while the concentration and the stirring speed are the parameters affecting the resistance. The retention increased slightly with concentration, but this was mainly determined by the membrane pore size.