In: Civil Engineering
A groundwater contains the following constituents to be treated by the lime-soda process to the minimum hardness possible has the following characteristics:
CO2 = 62.0 mg/L HCO3- = 250.0 mg/L as CaCO3
Ca2+ = 80.00 mg/L Cl- = 35 mg/L
Mg2+ = 36.6 mg/L SO42- = 96.0 mg/L
Na+ = 23.0 mg/L
The facility is to treat 50 x 106 L/day of water from this source using lime-soda ash to reduce the hardness.
a) Determine the total hardness, carbonate hardness, and non-carbonate hardness in mg/L as CaCO3.
b) Determine the lime and soda-ash dosages for softening (units of kg/day). Assume that the lime is 90 percent CaO by weight and the soda ash is pure sodium carbonate.