| The printing and dyeing wastewater has quality and quantity changes, high Chroma, high organic content and the characteristics of complex components and difficult to biological degradation, and traditional biochemical treatment is difficult to completely degrade organic pollutants. In the water environment increasingly grim situation, the urgent needs, improving of printing and dyeing wastewater treatment process, reducing the pressure on the water environment. In recent years, the rapid development of advanced oxidation technology of water treatment, such as dyeing wastewater is suitable for treatment of refractory organic wastewater,Wherein, Fenton reagent method is mature and easy to operate, which has achieved certain results in various types of industrial wastewater, but there are some disadvantages with Fenton reaction, such as pH scope harsher, low utilization rate of hydrogen peroxide, easy to form precipitation. Ultrasound and ultraviolet technology as a new green technology are widely used,but there are some deficiencies. Recently, scholars at home and abroad combining ultrasound,ultraviolet with Fenton wastewater treatment have made certain progress, but the reaction and process conditions are still not perfect.Based on the domestic and foreign relevant research, on Fenton, US-Fenton, UV-Fenton and US/UV-Fenton system were studied, including the combination of process optimization,dynamic analysis, reaction mechanism exploration, degradation test. Through the single factor experiment, we studied effects of US/UV-Fenton system reaction law of two kinds of simulated wastewater and the various factors on the degradation effect; We use orthogonal test to explore US/UV-Fenton system treatment the printing and dyeing wastewater with different section, and analyzes the significance of each factor. The mainly results are as follows:(1) Rhodamine B as the target pollutants, Wastewater is processed respectively by US, UV,Fenton, US-Fenton, UV-Fenton and US/UV-Fenton, and the US/UV-Fenton system to remove pollutants in wastewater is best. Through the establishment of Fenton, US-Fenton, UV-Fenton and US/UV-Fenton reaction system, that are in line with the pseudo first order reaction kinetics,The reaction rate constant US/UV-Fenton maximum, is 0.0461 L·mg-1·min-1. The reaction process is a strong synergy, and synergetic enhancement factor is 2.744. In the US/UV-Fenton system reaction process, ultrasound and ultraviolet light can not only promote the reaction, and the existence of favorable conditions in the reaction system, which can maintain a highconcentration of Fe2+, the ultrasound enhanced Fenton reaction ability, forming a good circulation system.(2) Rhodamine B and methylene blue as the target pollutant, we are systematically investigated the initial pH value, H2O2 dosage, the mole ratio of H2O2 and Fe2+, reaction time,ultrasonic power and other factors on the system of US/UV-Fenton treatment effect of wastewater, the results showed: US/UV-Fenton system can significantly broaden the pH range of oxidation reaction, and when the pH value was 1~12, the decolorization rate of the wastewater was above 72%, and the removal rate of CODCr was above 40%. In addition, US/UV-Fenton system can not only significantly improve the treatment effect of wastewater treatment, but also reduce the dosage of the drug, and reduce the operating cost. Under the optimum process parameters, the decolorization rate, CODCr removal rate and mineralization rate of US/UV-Fenton system on Rhodamine B wastewater were 99.9% and 92.1%, 61.85%,respectively, the biodegradability of wastewater(BOD5/COD value) was increased from 0.277 to0.503; and the decolorization rate of methylene blue wastewater, CODCr removal rate and mineralization rate were 99.36% and 90.45%, 63.88%, respectively, the biodegradability of wastewater(BOD5/COD value) increased from 0.145 to 0.481.(3) To deal with the wastewater a printing and dyeing enterprise wastewater and wastewater treatment as the research object, on initial wastewater pH value, H2O2 and Fe2+dosage, ultrasonic power, reaction time and other factors as the object of study were designed with five factors and five levels of orthogonal test, the system of research US/UV-Fenton processing printing and dyeing enterprises regulating tank effluent, the effluent from secondary sedimentation tank and through the SPSS software for data range, variance analysis to explore the factors significantly. The results showed: The initial pH value, ultrasonic power, H2O2 concentration and reaction time were all significant factors affecting the removal of CODCr when the US/UV-Fenton system was used as the pretreatment process, and within the range of experimental conditions, the influence of the factors was: pH value>ultrasonic power>H2O2concentration> reaction time, the concentration of Fe2+had no significant effect on the removal of CODCr from wastewater. Under the optimum process parameters, the removal rates of CODCr and TOC were 86.6% and 70.74%, respectively, and the biodegradability of wastewater was increased from 0.315 to 0.497. When the US/UV-Fenton system is used as the advancedtreatment process, the initial pH value, the ultrasonic power and reaction time are the significant influencing factors of CODCr removal, and under the optimal conditions, the removal rates of CODCr and TOC were 73.88% and 64.3%, respectively. |
PDF Full Text Request