The dead end ultrafiltration of dispersions of active carbon in water was studied. High flux of the permeate and effective purification were goals of the studies. Cyclical flow of the feed (cycling) was found to be the best condition for good purification. During the purification of the membrane, an air/water dispersion was injected into the hollow fiber membrane (air sparging) to improve the cleaning effect. A Simplex optimization of significant parameters was carried out. The behavior of pressure drop and module entrance pressure permitted the classification of the values into two groups. A different build-up of the cake of these groups during the filtration is possible.