DEVELOPMENT OF SOLAR PHOTO-FENTON PROCESS FOR THE REMOVAL OF POLLUTANT FROM INSTITUTIONAL WASTEWATER: OPTIMIZATION THROUGH RESPONSE SURFACE METHODOLOGY

Abstract

Water is fundamental to survival on earth. It is one of the important needs in human life. Wastewater from public are often rich in color and containing of chemical which needs a proper treatment before it is realizing into the environment. To make sure environmental protection, it is important to find the best method to overcome this environmental problem. It follows experimental methods for the treatment of institutional waste water. The objective of this study was to investigate the performance of employing solar photo-Fenton to treat institutional wastewater from jimma institute of technology. The color and COD removal percentages were analyzed by using an UV/Vis spectrophotometer and closed reflux method respectively. The effect of operating parameters on solar photo-Fenton process such as reaction time, hydrogen peroxide, solar radiation, and ferric on color, COD and turbidity removal were analyzed. The process was experimented by determining dependent variable by using operating independent parameters. The operating parameters were optimized by response surface methodology (design of expert 11.1.2.0). The quadratic regression models with estimated coefficients were selected for the percentage removal of COD, color and turbidity. It was observed that the model predictions match with experimental values with an R2 for COD removal, color removal and turbidity removal. The CCD was selected in this study because of its efficiency with respect to number of runs required for fitting a second order response surface model. Finally the study has much significance in using cheap and locally available solar radiation for the institutional wastewater treatment in solar photo Fenton process. The evaluation of this process by a central composite design with response surface methodology was evaluated. The relationship among operating variables such as pH, H2O2 dosage, Fe2+ dosage, and reaction time to identify the optimum operating conditions were evaluated. Quadratic models proved to be significant with very low probabilities (<0.0001) for the following responses: chemical oxygen demand (COD), Color and Turbidity. The optimum conditions were H2O2 dosage (781 mg/L), Fe+2 dosage (63 mg/L), pH (3.62) and reaction time (118.49 min) in this method. The experimental results of the maximum COD, Color and Turbidity removal rates corresponded well with the predictions, which were 99.78%, 100% and 100 %, respectively. The current study revealed that the solar photo-Fenton process in an advanced oxidation process was well efficient in the institutional wastewater treatment, achieving a 99.78% COD removal at conditions; pH=3.62, H2O2/Fe+2 ratio =12.4. This method achieved well degradation efficiencies for COD, Color and Turbidity reduced the treatment time comparing with the previous study. It was also recommended that the development of solar photo Fenton process effectively works in tropical zone of the globe thus it is better to the implementation of the method in large scale to the treatment of wastewater