| The conventional method for cyanide reduction
in effluents is alkaline chlorination, which requires the process to be
maintained at alkaline pH, to prevent formation of highly toxic cyanogen
chloride gas. Besides this, the appearance of precipitate upon addition of metal salts to wastewater containing cyanides,
gives no assurance that toxic complex cyanides have been eliminated.
| Chlorination does not oxidize iron cyanides to any degree, whereas
other metal cyanides such as nickel, cobalt etc require more time and significant chlorine excess.
| Photochemical oxidation overcomes the problem of conventional treatment and delivers consistent
output quality without any toxic by-products.
| In addition, photochemical
oxidation eliminates the fear of acidification of cyanide effluent by
human error, thereby liberating cyanide, making the process safe and