Experimental Study Of Pathogenic Microorgansims In Raw Water Disinfected By Hydrodynamic Cavitation Due To Combinations Of Circular Multi-orifice Plates With Venturi Tubes

With the rapid development of economic and society,The quality of Water environment and drinking water are increasing for people.In water treatment plant,Chlorine disinfection is often used in the traditional drinking water disinfection.However,chlorine disinfection can not avoid yielding some by-products."three-induced" disinfection by-products can be generated that injure health of human.The major ingredients are THMS and HAAS.ultraviolet disinfection and ozone disinfection are common methods in foreign water treatment plant.But Ultraviolet disinfection does not have the ability of persistent sterilization,also existing resurrection phenomenon.The sterilization of ozone is extremely strong,and without secondary pollution.But its disadvantages are easy to break down and high price.In rencent years,Some scholars have made some study on the disinfection of drinking water by hydraulic cavitation.some chlorinated by-products in water can be degraded,and natural organic compounds can be removed,this way can reduce the production of disinfection by-products.The combinations of circular multi-orifice plates with Venturi tubes was used to be a hydrodynamic cavitation device.The YE6263 pressure data acquisition system was used to collect the pulsating pressure of working section during the operation of the cavitation device.Analyzing the variation’s influenceing factors of the pressure and cavitation number along the flow field.Using PIV to shoot cavitation working section.Analyzing the distributions of longitudinal velocity,turbulent intensity and turbulent shear stress under different combinations.Based on above the flow characteristics research,making study on killing pathogenic microorganism in raw water by using the combination device.E.coli and total colony count in raw water were taken as the indicator bacteria of pathogenic microorganisms.The killing rates of E.coli and total colony count under different working conditions were detected by counting method of plate.The effects of cavitation number,orifice arrangement,orifice number,cavitation time,raw water percentage,throat length on the killing rates of pathogenic microorganism were analyzed.The experimental results showed that increasing orifice velocity and orifice number,prolonging cavitation time,lowering cavitation number,increasing the number of orifices,improving orifices arrangement and choosing appropriate raw water percentage and throat length,could increase the killing rates of E.coli and total colony count.Hydrodynamic cavitation has potential application prospect as a new technology with no disinfection by-products,safe and high efficiency.