Determine the lime (CaO) and soda ash (Na2CO3) dose, mg/L as CaCO3, to soften the following water to a final hardness of 90.0 mg/L as CaCO3. Assume the lime is 90% pure and the soda ash is 97% pure. (This is problem 4.18 out of the Water and Wastewater Engineering book by Davis)