The Experimental And Theory Research Of Breaking Excess Active Sludge By Ultrasonic

The large amounts of excess sludge that generated by Urban sewage treatment is becoming a more serious environmental and social problem.We mainly used the landfill method for excess sludge treatment in the past,but it difficult to continue because the huge sludge yield and the scarce land,even more important is the excess sludge contains a lot of resources, such as organic matter phosphate and so on,so Nowadays, the minimization and resource utilization of the residual activated sludge becomes the inevitable choice of sludge treatment under the background of development of resource recycling and environmental friendly society.This paper design ultrasonic crack test in accordance with the principle of orthogonal experiment in this context. We need ultrasonic cell disruptor to broken residual activated sludge in the four factors three levels orthogonal experiment,meanwhile we analyse and detect test indexes of sludge supernate after disintegration,such as the density of SCOD、 total phosphorus、protein、nucleic acid、peptidoglycan,find the optimal level combination of time、frequency、power and pulse ratio in the ultrasonic crack experiment,the primary and secondary order and significance of the four factors to the effect of ultrasonic crack.We analyse cracked process to apply the ultrasonic cavitation knowledge and improve the ability and efficiency of the ultrasonic sludge processing if the theory is combined with the practice.The orthogonal experiment results of ultrasonic crack residual activated sludge under the experimental conditions are:the optimal level combination is:lOmin、20kHz、600w、3:1;the primary and secondary order is:time>pulse>ratio>frequency>power;The significance of various factors is:the time is important,the pulse ratio、frequency and power is not important.As for the simulate part,we use the MATLAB software to simulate the multi-factor motion equation of bubble, bubbles collapse temperature and bubbles pressure at different bubble diameter based on the ultrasonic cavitation theory.In addition,we confirm a lot of experimental phenomena from the different simulation results.Ultrasonic sludge processing is an effective method to be used for excess sludge processing through the experimental research and simulation results in this paper.However,we only choose three level at every factor in the broken process,limited range,and the considering factors of bubble motion equation is limited,which will be our experiment purpose and direction diligently later.