Explain whether these are true or false and why c Surface wa

Explain whether these are true or false and why

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 effectively by ferric chloride (FeCls) 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

(1) Answer:- True ,FeCl₃ is used for coagulant for settling of clay particle (alkali) . It is done by sweep method. For the lowest concentration level of colloids , particles are removed with sweep coagulation once the coagulant dose is high enough.

When the colloid concentration is increased. The particles are at first removed by adsorption and charge neutralization. As the coagulant dose is increased particle stabilize with a reverse charge, by an increased in particle remove by sweep coagulation as the coagulant dose increases.

(2) Answer:- False

Quantity of alum do not increase with increase quantity of clay particles.