Exercise $($Lime$-$Soda Softening$)$

a$)$ Determine $Ca$ carbonate hardness $(CaCH)$ and Ca noncarbonate hardness $($CaNCH$)$

b$)$ Calculate the lime $(CaO{H}_2)$ and soda ash dosages for treatment of hard water.

Analysis of the water shows the following

Hardness $=280\frac{mg}{L}$ as $CaC{O}_3$

Magnesium $=21\frac{mg}{L}$

Alkalinity $=170\frac{mg}{L}$ as $CaC{O}_3$

Carbon dioxide $=6\frac{mg}{L}$