DECOLORISATION OF PULP & PAPER MILL EFFLUENT REMOVAL OF DYES

Abstract

Consumption of paper is the indication of the growth of civilization, industrialization of country. Higher the consumption higher is the growth rate. Due to increase in population in India the demand of paper is increasing rapidly and paper mills are producing more paper. There are many small paper mills in India, which are contributing in disposal of waste paper by recycling it. A wide variety of colored paper is made using various types of dyes. In spite of all precautions, some dyes remain untreated and come out of the mill with liquid effluent making it toxic and colored. The intake of dye by human being is harmful for their health. So removal of these dyes is essential. There are many processes for removal of color due to dye._ Adsorption is widely used process due to its simplicity. Usually activated carbon is used for adsorption. But due to its high cost there was a need of low cost adsorbent. In present study Bagasse fly ash is used as a low cost_adsorbent and their results were compared with the activated carbons (Laboratory grade, commercial grade) and coal ash. Auramine, Congo Red, Malachite Green, Orange-G, Methyl Violet, Rhodamine—B dyes that are commonly used in paper mills were used as adsorbates. Batch studies were conducted to see the effect of contact time, adsorbent dose, initial concentration of dyes and pH. The results were fitted in Langmuir and Freundlich isotherms. It was found that the bagasse fly ash is good adsorbent. Column studies were conducted on the removal of Methyl Violet and Rhodamine-B. Colored effluent from a large integrated mill was also treated using bagasse fly ash for removal of COD and color