Optimization of COD Removal from Pulp and Paper Mill Effluent using Electrooxidation

Abstract

Available treatment methods for pulp and paper industries waste effluent include biological treatment, adsorption, chemical precipitation, which are of high cost of the treatment and suitable for small and medium scale industries. Among the available methods, the chemical precipitation method is commonly used, which requires addition of chemical coagulants and generates more sludge compared to electrooxidation. The electrochemical method of organic matter destruction is a suitable alternative for the treatment of pulp and paper mill effluent, which combines the benefit of electrooxidation and electrocoagulation, capable of removing fine particles as a result of coagulation and electric field. The objective of the study is to evaluate the potential of electrooxidation for organic matter destruction from the pulp and paper mill effluent under various operating conditions such as pH, voltage, reaction time, and to optimize the operating conditions to maximize COD removal using response surface modelling. The wastewater for this study was collected from a pulp and paper mill located in Odisha, with wastewater collected from the outlet of the wastewater discharge before entering the treatment plant, and stored under 20 C to prevent its degradation. The results obtained from this study concluded 73.48% COD removal under optimum conditions (pH=9, V=11.2 V, RT=60 min) however, under experimental conditions, COD removal of 72.90% was observed. This batch monopolar electrooxidation system is efficient to remove COD from pulp and paper mill wastewater, and further studies are required on a continuous reactor to scale up the COD removal by electrooxidation. Keywords: Biological Treatment, Electrooxidation, Electrocoagulation, Chemical Precipitation, Sludge