ABSTRACT
Pulp and paper industry is a highly capital, energy, and water intensive industry, also a highly polluting process and requires substantial investments in pollution control equipments. Looking into the serious nature of pollution, the pulp and paper industry in India has been brought under the 17 categories of highly polluting industries. India produces 6 million tonnes of paper per year though 311 mills by consuming around 900 million m3 of water and discharging 700 million m3 of wastewater. Out of these about 270 small paper mills (capacity ≤10,000 tonnes per annum (TPA), having a total installed capacity of 1.47 MTPA) do not have chemical recovery units [1]. Effluents from this industry cause alternations in hydrographical parameters of the water body thereby causing tremendous
to the ecosystem. The sources of pollution among various process stages in pulp and paper industry are wood preparation, pulping, pulp washing, bleaching, and paper machine and coating operations. Common pollutants include suspended solids, oxygen demanding wastes, colour, basicity, heavy metals, alkali and alkaline earth metals, phenols, chloro-organics, cyanide, sulphides and other soluble substances [2]. Recent progress in the treatment of persistent organic pollutants in wastewater has led to the development of advanced oxidation processes (AOPs). Advanced oxidation processes make use of strong oxidants to reduce COD/BOD levels, and to remove both organic and oxidizable inorganic components. The processes can completely oxidize organic materials to carbon dioxide and water with the help of free hydroxyl radicals (OH· + OH−). Advanced oxidation process offer several advantages like process operability, absence of secondary waste and soil remediation. This method of treatment can be used either as a main treatment or as a hybrid technique [3]. It can also be used as a pre-treatment scheme for difficult wastewater for which feasible treatment methods are not available.
