What is one function of sodium bisulfite in wastewater treatment?

Sodium bisulfite plays a significant role in wastewater treatment primarily as a de-chlorinating agent. The reason it's effective for this purpose lies in its chemical properties. When introduced into chlorinated water, sodium bisulfite reacts with chlorinated compounds to neutralize them, forming harmless byproducts and thus removing chlorine from the water. This is crucial because chlorine can be toxic to aquatic life and can adversely affect the environment when effluents are released into water bodies. By ensuring that the chlorine levels are adequately reduced or eliminated before discharge, wastewater treatment facilities can meet regulatory requirements and protect ecosystem integrity.

Other options, while relevant in certain contexts of water treatment, do not pertain directly to the primary function of sodium bisulfite. The removal of nitrogen typically involves biological processes or specific chemical treatments, while stabilization of pH often relies on buffering agents rather than sodium bisulfite. Enhancing flocculation involves the use of coagulants or flocculants that facilitate the aggregation of particles in water, which is different from the action of sodium bisulfite.