drum filter wherein the solid wax is deposited on a rotating drum not shown in the form of a wax cake which is solvent washed on the drum the wash solvent comprises a 30 70 volume mixture of mek mibk at a temperature of about 70 u00b0 f which enters filter 14 via line 16 one volume of wash solvent is used for each three volumes of slurry entering the wax filter 14 the deoiled washed wax is then removed from the filter via line 18 approximately one volume of deoiled wax cake is produced for every six volumes of slurry entering the filter and the wax cake comprises approximately 30 volume wax and 70 volume solvent in the wax filter the foots oil solution is separated from the deoiled wax as a foots oil filtrate the wash solvent forms a wash filtrate the foots oil and wash filtrates are combined in the filter and passed to membrane unit 22 via line 20 membrane unit 22 contains a plurality of modified semi permeable membrane made from regenerated cellulose which preferentially permeates therethrough solvent from the combined filtrate to form a permeate richer in solvent and a retentate leaner in solvent than the combined filtrate feed fed to the unit in membrane unit 22 the combined filtrate contacts one side of said membranes at a temperature of about 70 u00b0 f and under a differential pressure across the membranes of.