PAC is even able to remove HA at low dosage.
The removal ratio was maintained more than 95% when the PAC
dosage was more than 20 mg/L. This removal ratio is higher than
the case of using NaOH as an alkaline chemical. Since CaCO3
behaves as a coagulant reagent, the sedimentation velocity was
significantly high and the SV was reduced about half compared
with the case of using NaOH as a neutralizer. Therefore, the
utilization of CaCO3 combination with coagulation method by PAC
is efficient in removing HA because it is able to perform both as
alkaline chemical and as a coagulant agent about the same time.