TREATMENT OF AGROBASED PULP MILL EFFLUENT USING -ADSORPTION

Abstract

Paper is an essential component of a modern society. Paper consumption for any country closely follows the growth economics of that country As a component of people's consumption, paper contributes about 1% to the annual value of world economic activity — gross domestic product (GDP). For developing countries like India, the consumption of paper per unit of income has increased over the years. In spite of its significant contribution, pulp and paper industries are one of the most polluting industries discharging large amounts of waste — air, liquid and solid wastes. The wastewater from paper mills have high BOD, COD, suspended solids, pH, temperature and colour. The environmental pollution problem for agro based paper mills is different than the large integrated paper mills due to lack of recovery system and use of short fibre raw materials. Among the several treatment processes, adsorption still continues to be the most widely used process. Adsorption by activated carbon is the most widely used process in wastewater treatment. But because of high cost and regeneration losses of activated carbon there is a continuing search for the low cost adsorbents. In present investigations, wastewater samples collected from different sections of a small agro based paper mill were treated both with activated carbon and low cost adsorbents for the removal of colour and COD. The low cost adsorbents used were the carbon slurry, generated in fertilizer plants, and bagasse fly ash generated in sugar mills. In batch studies, the adsorption isotherms have been used to know the effectiveness of the adsorbents. The Langmuir and Freundlich isotherms have fitted best for the process and effect of contact time is also observed. Column study of black liquor was conducted and breakthrough curve is presented. By comparing the adsorption capacities of carbon slurry and bagasse fly ash it is observed that the adsorption capacity of carbon slurry is more than that of bagasse fly ash.