WASTE AND WATER TREATEMENT

The ability of chitosan to bind metals, combined with its flocculating properties, provide applications in treating drinking water, pools and spas, and various waste streams. So far, this type of application has found the greatest popularity in Japan.

Drinking water : Chitosan or its derivatives combined with activated carbon can purify drinking water. The biopolymer removes two broad types of pollutant: organic compounds such as o- dichlorobenzene, and heavy metals such as lead, mercury, cadmium, copper and zinc. Tests have shown that this treatment reduces the amount of lead to below the 10 ppb (parts per billion) safety limit set by the EPA.

Pool and spas : Derivatives of chitin flocculate, matter such as oils. soaps, dirt and plaster dust suspended in water. ims nas potennai use in claniymg pools, spas, hoi tubs, fountains, ponds, lakes and other areas of water. The derivatives also chelate metals that discolor water and stain pools.

Recovering metals : The chelation ability referred to in the orevious paragraph offers the opportunity to use chitosan to recover metals from electroplating, electronics manufacturing, metal finishing, photographic processing and the production of jewelry. Metals that chelate with chitosan and its derivatives include cadmium, chromium, cobalt, copper, iron, nickel, lead, manganese, mercury, nickel, silver and zinc.

Treating food wastes : Chitosan binds to colloidal and dispersed particles in waste streams from rendering plants, vegetable processing plants and egg processing plants, thereby permitting recovery of proteins to use as feed additives, as indicated in Feed Ingredients, above. Chitosan can also be applied to flocculate other wastes, such as effluents from sewage and paper mills.