Sodium Bisulfite is a reducing agent and reacts readily with dissolved oxygen. Sodium Bisulfite is used for the dechlorination of water and wastewater, boiler water treatment, flue gas desulfurization. In the treatment of drinking water, Sodium Bisulfite is added after super chlorination, to diminish the residual chlorine. In the treatment of wastewater, Sodium Bisulfite is added after disinfection with chlorine before discharging the effluent. Excess of chlorine can have negative effects on aquatic life. It is an efficient agent for the removal of excess chlorine, bromine, iodine, potassium permanganate, and chromium trioxide. Sodium bisulfite is also used for preventing oxidative corrosion in large piping systems.