Water Treatment Chemicals


Sodium meta bisulfite or sodium pyrosulfite is an inorganic compound of chemical formula Na2S2O5. The substance is sometimes referred to as disodium(meta bisulfite). It is used as a disinfectant,antioxidant and preservative and agent.

When mixed with water, sodium meta bisulfite releases sulfur dioxide (SO2), a pungent, unpleasant smelling gas that can also cause breathing difficulties in some people. For this reason, sodium meta bisulfite has fallen from common use in recent times, with agents such as hydrogen peroxide becoming more popular for effective and odorless sterilization of equipment. Released sulfur dioxide however makes the water a strong reducing agent.


Sodium Meta Bi Sulphite is one of a group of preservatives known as bisulphite. It is a food preservative, cosmetic and industrial bleaching agent, and an ingredient in the developing solution for film and photography. Evidence exists that it is also an immune-system toxin. As part of the group of sulfites, sodium meta bisulphite can provoke reactions in people, particularly asthmatics, ranging from gastrointestinal discomfort and hives to asthma attacks.

Food Uses
Sodium Meta Bi Sulphite is used as a preservative in foods such as baked goods, jams, wines, dried fruit and many sauces. Sulphite can be added before or after cooking. Fruits and raw vegetables used to be sprayed with sulphite, but this practice was banned by the U.S. Food and Drug Administration in 1986. Sodium meta bisulphite is also used as an antibacterial agent in wine, although some manufacturers have begun using potassium meta bisulphite instead. Some winemakers have claimed that sodium meta bisulphite increases the sodium content of wine.

Industrial Uses
Sodium Meta Bi Sulphite exists in both food-grade and non-food-grade forms. The non-food-grade form is an industrial bleaching and reducing agent; it is also used to remove excess chlorine from drinking water and as a photographic developing and fixing bath agent.

Medicinal Use
Sodium Meta Bi Sulphite is an antioxidant additive in injectable medicines and is also used as a reducing agent in pharmaceuticals. Some medical lotions may contain sodium meta bisulphite; even in topical preparations, however, sodium meta bisulphite may induce allergic or sensitive reactions.