Experimental Study On Disinfection Of Escherichia Coli By Hydrodynamic Cavitation Due To Square Multi-Orifice Plates

With the advance of the standard of living, people put forward higher demand for the quality of drinking water. The drawbacks of the traditional drinking water disinfection technology also gradually appear,it is necessary to develop new drinking water disinfection techniques.Applying the hydraulic cavitation in the field of drinking water disinfection is also a new technology to use hydraulic cavitation energy.The collapsed cavitation bubbles resulting in the generation of microjet and shock wave can release tremendous amounts of energy in short time and the local extreme high temperature and pressure generated by bubble collapse in cavitation can induce rupture of chemical bond of water and occurrence of free hydroxyl radical ? OH and H2O2.It has the good sterilization effect, does not produce secondary pollution, simple equipment, and convenient operation and is suitable for the process of industrialization, etc.In this paper, the research mainly divided into two parts. In the firstpart, Numerical simulation and pressure experimental study on turbulence cavitation characteristics of hydrodynamic cavitation advice were studied by square orifices plate hydrodynamic cavitation device which was independently designed in the Hydraulics Laboratory of Zhejiang University of Technology. The pressure characteristics behind multi-orifice plates were experimental studied by the pressure data acquisition system of SINOCERA-YE6263. The effect of multi-orifice plates with different orifice velocity, size, number and arrangement mode to the time average pressure and cavitation number were considered.The second part experimentally studied disinfection of Escherichia coli, as an indicator culture of pathogenic microorganisms, by using the square multi-orifice plates as the reactor of hydrodynamic cavitation.Based on the cavitation test of different orifice velocities, different orifice geometric parameters and different initial concentrations of Escherichia coli, variations of killing rate of Escherichia coli with cavitation number,orifice velocity, initial concentration, number and size and arrangement mode of multi-orifice were analyzed. To provide an experimental reference for exploring the new way of drinking water disinfection. The experimental results showed that enhancing the velocity, choosing the appropriate initial concentration, improving the treatment time and increasing the number and decreasing the size of orifice on the plates can increase the killing rate of Escherichia coli in water.