A mineral slurry containing 30 wt% solid (s.g. = 2.5) in water is fed to a rotary drum filter, 1 m in diameter and 2 m long. The drum rotates 15 revolutions per hour and 25 per cent of its surface is in contact with in the slurry at any given instant. Filtration is carried out under an internal pressure of 40 kPa abs, with the internal filtrate level at 300 mm below the drum's axis. Filtrate is produced at an average rate of 750 kg/h and the filter cake has a voidage of 0.5. a. Calculate the average thickness of the filter cake formed. b. Determine the average specific cake resistance. The drum filter is malfunctioning and filtration needs to be carried out temporarily in a plate and frame filter press with 0.5 m x 0.5 m frames. Filtration will take place under constant- pressure condition at the same pressure differential as with the continuous drum filter. Filtration would require 20 minutes, and filter cake washing would take 10 minutes. If the filtration rate obtained with the filter press is equal to the overall filtration rate of the drum filter, determine: c. the minimum number of plate and frames required; d. the maximum thickness of the filter cake formed in each frame. For both filters, assume the filter cake to be incompressible and neglect the resistance of the filter medium. DATA Filtrate density: 1000 kg/m3; Filtrate viscosity: 1 cp Atmospheric pressure: 101.3 kPa