A dosage of 40mg/L of alum is added for the coagulation of water in the water treatment plant with a 20 MGD capacity. To supplement the natural alkalinity for good floc formation, lime (CaO) is also added. It is desired to react only 10mg/L (as CaCO3) of natural alkalinity.
Calculate the daily lime required (lbs/day) in this plant if injected lime (CaO) has 85% (w/w) purity.