An assessment of the viability and utility of the conventional cake filtration theory was made by comparing the results based on the conventional theory with those obtained from more exact numerical analyses. The validity of the assumptions on which the conventional theories are based, such as negligible solid motion, constant liquid velocity through a cake and constant and time-invariant wet to dry cake mass ratio was examined. Based on the comparisons, a more accurate procedure of applying the conventional theory was presented. (C) 2003 Elsevier Science Ltd. All rights reserved.