STUDIES ON THE REMOVAL OF CHROMIUM FROM WASTEWATER

Abstract

Chromium waste discharged from industries may consist of chromium in hoxnvnlr,w- t-rivnlent form. ThoAri industries are inks and industrial dyes manufacturing, chrome tanning, aluminium anodizing and other metal cleaning, electroplating, etc. Hexavalent form is generally believed to be more toxic and is known to be a carcinogen The significance of hexavalent chromium toxicity and the need for treatment of industrial waste waters for hexavalent chromium removal prior to discharge to water ways is a big problem even today. Chromium pollution affects the human-being, small animals, marine and aquatic life, waste water organisms and biological treatment plants. Numerous articles in the literature have been devoted to various aspects of hexavalent chromium toxicity and treatability. At present many methods are available for removal of chromiumfromwaste waters such as reduction and precipitation, adsorption, ion-exchange, reverse-osmosis, freeze concentration, etc. In the present work five different materials, namely, Hydrogen sulphide gas, sodium metabisulphite, Calcium hydroxide, Activated charcol and Aluminium oxide have been used for removal of hexavalent chromium from aquous solution. The experimental results show that H2S gas is the most effective in removing chromium from wastewater.