Experimental Study On Degradation Of Refractory Wastewater By Hydrodynamic Cavitation Due To Venturi Tube And Triangular Orifices Plates

With the development of modern civilization and the speeding up of urbanization and industrialization, the problem of water pollution and water shortage has become obvious and been a more and more serious threat to the human survival and social development. Therefore, the use of advanced water treatment technology to improve water environment and protect water resources is particularly important. Hydraulic cavitation technology as a new processing method, not only can effectively degrade complex organic compounds and biological refractory material, but have simple operation, easy to implement, less energy consumption and no secondary pollution, etc.In order to study the use of hydraulic cavitation effect on the effect of treating refractory wastewater, and explore the influence of different factors on the wastewater degradation rate, to optimize the parameters of the hydraulic cavitation device and its operating conditions, this paper carried out the following research works by the self-developed hydrodynamic cavitation due to the combination of the Venturi tube with triangular orifices plate designed and built in the Hydraulics Laboratory at Zhe Jiang University of Technology.(1) The experiment choosed hydrophobic material nitrobenzene as the target pollutant and used the Venturi tube hydraulic device to process, to determine the Venturi tube length at the maximum degradation rate, making the zetetic experiment for subsequent processing;(2) The experiment used the combination of the Venturi tube with triangular orifices plate cavitation device to compound the p-nitrophenol and nitrobenzene mixture and discussed the effect of the orifice velocities, run time, initial concentrations, orifice numbers, orifice sizes and cavitation number on the degradation of the mixture wastewater, providing a new processing method for hydrophilic and hydrophobic mixture wastewater.(3) Select methylene blue to capture hydroxyl free radicals generated by the hydraulic cavitation and detect the production by the ultraviolet spectrophotometer, discussing the relation of the hydraulic cavitation intensity and hydroxyl free radical production.(4) The practical chemical wastewater was treated in the combination of hydrodynamic cavitation device. Choose COD as detection index and discussed the effect of orifice numbers and sizes, initial concentrations, run time, cavitation number and pH on the COD degradation of the chemical wastewater to determine the optimal parameters of hydraulic cavitation device and operating conditions.