Question 2 Answer BOTH parts, (a) and (b). In a batch sedimentation experiment on a slurry of solid concentration 30 kg/m', the interface heights are measured at various times and tabulated as: Time (min): 0 5 15 25 35 45 55 70 Height (cm): 100 90 70 50 32 25 22 21 (a) Determine the solid settling velocities at the interface between suspension and clear liquid and the corresponding solid concentrations at t=15, 25, 35, 45, 55, 70 min. (12 marks) (b) A continuous thickener is used to treat the same slurry at a rate of 0.04 m/s. If the underflow solid concentration is 80 kg/m, (1) Determine the rate limiting concentration in the sedimentation tank below the feed point and the corresponding total settling flux. (8 marks) (ii) Determine the area required for the sedimentation tank if 10% over design is assumed (5 marks) )