Hydrodynamic Cavitation: Its optimization and potential application in treatment of Pigment Industry Wastewater

Abstract

Paper presents the application of Hydrodynamic Cavitation technique in reduction of Chemical Oxygen Demand (of Chemical Oxygen Demand (COD) and its various fractions from the Pigment Industry wastewater. Orifice plate with dimension of single hole of 1.5 mm is used in this study. The sample were analyzed at different pressures of 2 bar, 3 bar, 4 bar, 5 bar and 6 bar at different time intervals of 30 min, 60 min, 90 min, 120 min and 180 min. The optimum time and inlet pressure for maximum COD reduction is obtained at 5 bar and 120 min. The samples are analyzed in two stages. In stage first stage, samples are treated with hydrodynamic cavitation only and filtered thereafter. Both the unfiltered and filtered samples were analyzed for various parameters such as COD (filtered and unfiltered), BOD (filtered and unfiltered), TDS and pH. In stage two, the samples are treated with aeration for optimum time followed by Hydrodynamic Cavitation. The optimum time of aeration was obtained at 36 hrs. Response Surface Methodology was used to check the sensitivity of the Hydrodynamic Cavitation set up. Optimization using RSM provided optimum results with desirability 0.798 when pressure was at 5 bar and time of reaction was 120 min.