Dechlorination

Dechlorination is the removal of free and total combined chlorine residue from chlorinated wastewater effluent before its reuse or discharge to receiving waters. Chlorine compounds react with many organic compounds in the effluent to produce undesired toxic compounds that cause long-term adverse impacts on the water environment and potentially toxic effects on aquatic microorganisms. It might be brought about through the use of activated carbon, or through the addition of a reducing agent like as sulphur dioxide (SO₂), sodium sulphite (Na₂SO₃) or sodium metabisulphite (Na₂S₂O5). It is significant to note in which dechlorination will not remove toxic by-products which have already been produced.