This book deals with water pollution due to presence of hexavalent chromium from different industrial effluents and its adverse effect on flora and fauna of ecosystem. This paper also provide a low cost treatment method based on biosorption using activated carbon derived from rice husk, an agricultural residue and compares the performance with other biosorbent as well as commercial adsorbents. Various equilibrium and kinetic studies were reported here to quantify the performance of adsorbents.