In: Chemistry
A surface water is coagulated with a dosage of 30 mg/L ferrous sulfate and an equivalent dosage of hydrated lime (Ca(OH)2).
2FeSO4*7H2O + 2Ca(OH)2 + 0.5O2 -> 2Fe(OH)3 + 2CaSO4 + 13 H2O
A ) How many pounds of ferrous sulfate are needed per MGD of water treated.
B) How many pounds/mil of hydrated lime are required assuming, a purity of 70% CaO?
C) Determine the pounds of Fe(OH)3 sludge are produced per MGD of water treated.
30 mg of FeSO4.7H2O present in 1 liter solution
1 gallon = 3.785 Liters
1 MGD = 3.785 million Liters
1 MGD contains iron sulphate = 3.785 * 30 *10^-3 *10^6 g
= 113550 g
1 g = 0.00220462 pounds
113550 g = 0.00220462 * 113550 pounds
= 250.3346 pounds.
equivalent dosage of Ca(OH)2 is also involved in the reaction.
hence mass of Ca(OH)2 = 250.3346 pounds
the compound is 70 % of Ca(OH)2 = 250.3346 pounds
hence required mass of Ca(OH)2 = 250.3346 * (100/70)
= 357.621 pounds of Ca(OH)2 required.
1 mole of FeSO4 *7H2O produces 1 mole of Fe(OH)3
278 g of FeSO4 *7H2O produces 107 g of Fe(OH)3
250.3346 pounds of FeSO4 *7H2O produces (107/278) * 250.3346 pounds of Fe(OH)3
= 96.352 pounds