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

With the rapid development of economy and society, environmental awareness of human beings is gradually increasing, while the conventional wastewater treatment technique can not meet the new requirement of environmental protection. Hydrodynamic cavitation technology, as a new processing method in recent years, not only be characterized by high efficiency, energy saving, but also be of many other advantages including simple operation, no reagent adding and it shows a broad application prospect.This paper presents experimental studies of the effect of the hydrodynamic cavitation on degradation of refractory pollutants. The triangular orifices plates were chosen as the cavitation reactor to remove the refractory pollutants. In order to explore the influence of different factors on the degradation rates of pollutants, and optimize the parameters of the hydraulic cavitation reactor and its operating conditions, this paper carried out the following work by self-developed hydrodynamic cavitation reactor due to the triangular orifices plates in the Hydraulics Laboratory at ZheJiang University of Technology.(1) P-nitrophenol(PNP) was chosen as the target pollutant of hydrophilic pollutants, and the triangular orifices plates were used as the hydrodynamic cavitation reactor, the effects of different orifice velocity, cavitation number, initial concentration of wastewater, orifice number, orifice size and treatment time on the degradation rates of p-nitrophenol were measured;(2) The pressure data acquisition system was used to measure the pressure of hydrodynamic cavitation and study the pressure characteristics of the triangular orifices plates and the dynamic characteristics of hydrodynamic cavitation;(3) The COD was utilized as the detection index to investigate the effects of hydrodynamic cavitation due to the triangular orifices plates on degradation of chemical industry wastewater. The effect of orifice size, orifice number, initial concentration of wastewater, treatment time, pH value and cavitation number on the degradation rates of wastewater were measured and the optimal parameters and operating conditions of hydrodynamic cavitation reactor were determined.