Mechanism Of Micro-bubble Air Flotation In Water Treatment Process And Flotation Experiment

It has been a long time since the usage of air flotation water purification technology in maintaining solid-liquid separation. After the invention of this technology, it has been put into large scale of use in the field of water supply and drainage so that the treatment and purification of sewage become no longer difficult. The advantage of the air flotation water purification technology includes low energy consumption, less pollution and the ability to handle lightweight suspended particles which is difficult to separate in the gravity sedimentation method. Therefore, the air flotation water purification technology played an important role in sewage treatment, water purification and sustainable usage of water resources.In this paper, we introduces the current status of water purification technology and the principles of air flotation water purification. The process of micro-bubble-floe attachment and surfacing in water treatment is studied. The effect of contact angle, surface tension, ζ potential, size, quantity and other parameters of micro-bubbles on water treatment has been analyzed.After that, the importance of micro-bubble generator in the air flotation water purification technology is introduced. and the principle and structure of two different types (mixed flow and self-absorption) of micro-bubble generator are analyzed. With the help of fluid dynamics theory, a mathematical model that applies to internal three-phase flow field of both the two micro-bubble generators is established, three-dimensional and two-dimensional numerical simulation of the flow field is carried out. The effect of structural parameters on the internal flow field is studied. In water for foam test, the bubble size and quantity of two micro-bubble generator are measured.In order to investigate the removal efficiency of the lightweight suspended particles, aiming at water samples containing Cryptosporidium oocytes and the eutrophication high algae water, research and experiments are carried out to discuss the efficiency. in the experiment containing Cryptosporidium oocytes, we analysis the experimental results of other researchers, using multiple linear regression analysis to derive the model of Cryptosporidium oocytes removal rate. In High algae water, jet and self-priming micro-bubble generator were used, analyzing the performance Characteristics of the two different structures of micro-bubble generator.This paper was based on the National Natural Science Foundation, studied two kinds of water with different sources of pollution, and has played a certain role in promoting the application of air flotation water purification technology in water treatment.