Indicate if the statements below are True or False Explain y

Indicate if the statements below are True or False. Explain your answer and provide a qualitative/mechanistic explanation.

A. Surface water of low particle concentration and low alkalinity can be coagulated effectively by ferric chloride (FeCl3) in a “sweep floc” mode.

B. If a dose of 25 mg/L alum (about 10-4 M) is needed for effective coagulation of 15 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 True.

The sweep flocs can be described as large aggregates of Al(OH)3/Fe(OH)3 that are formed when Al/Fe salt is added to water. This process is good at near neutral pH. Here water is of low alkalinity. Hence process will work fine.

B_) True.