Determine the lime and soda ash dose, in mg/L as CaCO3, to soften the Village of Galena’...

Determine the lime and soda ash dose, in mg/L as CaCO₃, to soften the Village of Galena’s water to a final hardness of ≤ 130.0 mg/L as CaCO₃. Assume the water temperature as pumped from the ground is 8.5^oC. If the price of lime, purchased as CaO, is $100 per megagram (Mg), and the price of soda ash, purchased as Na₂CO₃ is $200 per Mg, what is the annual chemical cost of treating 0.500 m³ /s of this water? Assume lime is 93% pure and soda ash is 95% pure.