Determine the lime and soda ash dose, in mg/L as CaCO3, to soften the following water to...

Determine the lime and soda ash dose, in mg/L as CaCO₃, to soften the following water to a final hardness of 90.0 mg/L as CaCO₃ . If the price of lime, purchased as CaO, is $61.70 per megagram (Mg), and the price of soda ash, purchased as Na₂CO₃, is $172.50 per Mg, what is the annual chemical cost of treating 0.050 m 3 /s of this water? Assume the lime is 90% pure and the soda ash is 97% pure. The ion concentrations reported below are all mg/L as CaCO₃.