6. (10 pts) A pilot scale ion exchange column was used to develop design data for a softening system for the Village of Dolomite. The data are shown below. The design flow rate is 7.000m3/d. The design final hardness is 120mg/. as CaCO. The manufacturer's operating eapacity to breakthrough is 50%%. Assume a two-column system and that there is no leakage before breakilurough. Determine the mass of resin required Raw water data: Ca2+=111.0mg/L as CaCO2,Mg2+=131.8mg, as CaCO2 Column specification: diameter =10.0cm; height 150.0cm; leakage 10mg/L. Resin density =0.80g/cm3 (moist busis) Moisture content =70%; Flow rate through the column =0.25m3/h