REMOVAL OF TOXIC ORGANICS FROM PULP AND PAPER MILL EFFLUENT USING CATALYTIC WET AIR OXIDATION

Abstract

Paper is the essential component of the modem society. As a component of the people's consumption, paper contributes about 1% to the annual value of the world economic activity — gross domestic product (GDP). For developing countries like India, the consumption of paper percapita has increased over the years. Inspite of its significant contribution, in India, the pulp and paper industry has been brought under the list of 17 most polluting sectors as identified by the Central Pollution Control Board. The wastewaters from these mills have high BOD, COD, pH, temperature and colour. However, rising general awareness, stricter implementation of environmental regulations and the need to survive in a highly competitive market are slowly forcing the mills to upgrade and improve environmental practices. the several' trcRtllWfit processes, Wet Aii Oxidation is a newly emerging technique for the treatment of the toxic and non-biodegradable industrial waste. Wet air oxidation (WAO) involves the liquid phase oxidation of organic or oxidizable inorganic components at elevated temperatures and pressures using a gaseous source of oxygen (usually air). Wet air oxidation is used as a pretreatment step so that resulting solution can be treated biologically. Since wet air oxidation involves high temperature and high pressure, the use of an appropriate catalyst is highly desirable for conducting this reaction at reduced temperature and pressure conditions. In the present work, CWAO of the pulp and paper mill. was carried out at atmospheric pressure and at temperatures 70-95 °C to remove the toxic organics from the effluent, the catalysts used for the tests include CuO-ZnO/A1203, CuO-ZnO/Ce02 and Perovskites.