5 Indicate if the statements below are True or False Explain

5. Indicate if the statements below are True or False. Explain your answer and provide a a. The lower the concentration of particles in water is, the easier to remove the b. Coagulation of a dilute suspension of particles by alum in a \"sweep floc\" mode is c. Surface water of low particle concentration and low alkalinity can be coagulated d. If a dose of 25 mg/L alum (about 104 M) is needed for effective coagulation of 15 qualitative/mechanistic explanation. particles via coagulation and flocculation. more efficient at pH 6.0 than at pH 3.5 effectively by ferric chloride (FeCl3) in a \"sweep floc\" mode. mg/L clay particles at near neutral pH, then a dose of about 50 mg/L alum will be needed for effective coagulation of 30mg/L clay particles at the same pH

Solution

A> False. As concentration of particles decrease, turbidity decrease. With High Turbidity small doses of Coagulants are required. But as turbidity decrease, low dose of coagulants becomes less effective and Coagulants aids are added to accelerate the process of caogulation.

B> True, For Sweep Floc formation low turbidity and high alkalinity of water is favourable case.

C> True. Because of low colloidal concentration, coagulation is most difficult and low alkalinity does not permit the effective formation of Al(OH)₃ floc. FeCl₃ is preffered over Al(OH)₃ Floc.

D> True. 1 Mole of Alum gives two moles of Al(OH)₃ i.e. 1 gm of alum gives =.234 gm of Al(OH)₃.

Also this identity is to be maintained=> gram equivalent of one thing = Gram equivalent of other thing.

This way twice the value of alum will be required for alum for twice the clay particles.