Use of industrial waste for reduction of COD from paper mill effluent

Batch experiments have been carried out to study the reduction of COD from pulp and paper mill effluent by blast furnace flue dust (BFD) and slag generated in steel plant and chrome alloy plants respectively. Reduction efficiencies which attain equilibrium after 8 hours, were observed to be more than 72% and 57% for the BFD and slag respectively. The adsorption processes for both adsorbents follow first order kinetics and Freundlich adsorption isotherms. Particle diffusion studies indicate that predominately adsorption of COD contributing components takes place rapidly by external mass transfer followed by intraparticle diffusion. Column experiments indicate that the reduction of COD decreases with increasing flow rate and decreasing bed height. The break through time and bed depth data show the applicability of BDST model.