Determination of Optimal pH and Running Time for Treatment of Textile Industry Effluent Using Ozonation Method

Wastewater from the textile industry is one of the most polluted industrial effluents. Many different methods have been used for treatment of this type of effluents. Since ozone is a powerful oxidizing agent and attacks the double bonds of the dye molecules, it can be efficiently used for treatment of this type of wastewater. The present study aims to determine the optimum running time and pH for removal of pollutants from the effluent. In the present research, experiments were carried out in a 4.2 l reactor with a 1393.431 mg inlet ozone. Colour and COD removal efficiencies were measured at different time periods and at pH values of 5 and 9. Results show that using the ozonation method under the optimum condition of a pH value of 9 and a running time 90 minutes reduced chemical oxygen demand (COD) by 21.6% and colour by 82.56% (Pt-Co scale), 73.63% (at 400 nm wavelength) and 90.76% (at 575 nm wavelength). Since the use of ozone alone to achieve the desired level of treatment is not cost effective, it is recommended to use this method in combination with other methods.