Researchers are investigating the various biomaterials as an effective alternative to the activated carbon for removal of dyes from aqueous solution. Some of the biosorbent have shown extremely high capacity for removal of dyes. But being a biomaterial, consists of organic molecules, they also contribute organic matter to the solution during adsorption process and thus contribute to the COD of the treated solution. There is a very strong and strict restriction on the value of COD of the industrial waste water before discharging into environment. So the biomaterial which is capable of removing the dyes below the prescribed limit, if increases the COD then it is not suitable for use in the adsorption process for removal of dyes from industrial effluent. In this paper the suitability of raw rice husk, sodium carbonate treated rice husk and potassium hydrogen phosphate treated rice husk has been examined and found that raw rice husk is not suitable biosorbent where as treated rice husk are the promising biosorbent.