Ferric chloride (FeCl3) is going to be used as a coagulant in a water treatment plant at a dosage of 40 mg/L. To avoid consumption of alkalinity and changes in pH, you plan to evaluate the use of caustic soda (NaOH) compared with quicklime (CaO).
What final concentrations of NaOH and CaO (in mg/L) would be required to react with the FeCl3 without consuming alkalinity?