Problem 4. A groundwater containing 240mg/L of Ca2+ and 48mg/LofMg2+ will be treated for hardness removal using a cation exchange resin. The hardness removal capacity of the resin is given as 2mgCaCO3/ml resin. The daily volume of groundwater to be treated is 300m3. Other design parameters: Hardness removal efficiency =%100 Number of ion exchange columns (n)=6 Column hydraulic retention time (EBCT)=5min Regenerant solution: %10NaCl (in weight) Density of regenerant solution =1000g/L Based on information given in the problem: a) Calculate the volume of resin required for each ion exchange column. (5p) b) Calculate the regeneration period as min for each ion exchange column. (10p) c) Calculate the volume of NaCl solution required for the regeneration of all resins at a single regeneration period. (10p) Molecular weights (g/mole): Ca=40,Mg=24,Na=23,Cl=35.5,O=16