3. Consider a two-stage nanofiltration process in an effluent treatment plant. (20 marks) F F FA F, C CR F. A feed stream containing 40 kg/m of pollutant is subjected to the first stage NF at a flow rate of 300 kg/h. ) If the concentration of the pollutant after first stage NF reduces to 3 kg/m then find the length of the rectangular channel. Width of the channel is 5 m. Osmotic pressure of the pollutant for stage 1 is expressed as: 11(Pa) = 5000C. Also, consider F = 0.8F. (ii) Considering that the length of the membrane module for the 2nd stage is same as that of the previous one, find the width of the 2nd channel if the pollutant concentration at the end if 2od stage is 1 kg/m. Osmotic pressure of the pollutant for stage 2 is expressed as: 11,(Pa) = 4500C. Consider Fr=0.6F, The operating pressure is kept at 758 kPa for both the stages. The membrane permeability is 2 x 10" m/Pas and consider the mass transfer coefficient to be 6 x 10 m/s