How to remove Chlorine (dechlorination of water) from the feed water before Reverse Osmosis Desalination or prior to Discharge
Concentration of residual Chlorine after disinfection or oxidation is often too high for distribution, discharge to the environment or for other downstream processes such as reverse osmosis desalination.
Amongst other methods, chemical dechlorination by means of Sodium Bisulphite (NaHSO3) is very common for various reasons:
The reaction between Chlorine and Sodium Bisulfite is practically immediate, comes at a lower costs than other chemicals and is widely available
Dosing Control in Water Chlorination: Flow-Paced plus Residual Feedback
Feedback dosing control, where a flow-pace control is combined with a residual Chlorine or ORP sensor feedback reading, is the best available dosing control for disinfection or oxidation. However, the lag-time between the dosing point and the sensor reading can be problematic when the feedwater quality is inconsistent.