Research On Advection-type Pressurized Dissolved Air Flotation Water Treatment

As an important part of the human beings and other living beings, water is the foundation of the human beings’ survival. There exists a serious short of the water resources in our country, and in order to make a full use of the water resources, the recycling for sewage treatment is needed. The pressurized air flotation water treatment is a method of purification of the water treatment. This method is:introduce a certain pressure flotation pool of dissolved air flotation tank water when the raw water into the flotation tank, and it will release a large number of micro-bubbles when the pressure reaches the rapid decompression to atmospheric pressure, and the bubbles is adhered to the suspended dirt and accelerate the contaminants floating to the surface, and collected by the slagging apparatus and discharging dirt. Pressurized air flotation water treatment is widely used in the water treatment for its significant effects, such as its big air solubility and large amount of the micro-bubbles.The subject which elaborates many key technical problems is on the basis of a full overview flotation water treatment research status of the proposed type of advection pressurized dissolved air flotation.This determines the effect of water treatment systems and the content of the study of this subject.First, the theoretical issues involved in the pressurized air flotation water treatment research, including pressurized dissolved air law (Henry’s law), out gassing principle of the two-film theory, micro-bubbles and grand theories and adhesion of dirt mechanism, this theoretical issues lay a theoretical foundation for pressurized air flotation water treatment device.Secondly, model for the flotation tank flotation pool in order to research air-water two-phase flow pattern and flotation effect. First, simplify the structure of the advection-type flotation tank, using GAMBIT software modeling, then using FLUENT software simulate for the flotation tank model. The content of simulate including in flotation pool or without grating angle, whether the flap angle, different depth ratio of flotation effect analysis. And obtained these key parameters of results of the analysis, and provides a theoretical basis for the optimal design of the flotation tank.Furthermore, use the above result theory and simulation analysis design stratospheric pressurized air flotation water treatment test prototype. The experimental prototype is conducive to the study of the structure of the form, such as the test of the water cycle, adjustable recirculation flow, variable air-entraining, easy to form a vortex within the dissolved gas cylinders cut the form to the entrance, half transparent structure of the flotation tank, the baffle removable, multi-spacing grid plate and a wide range of adjustment grid plate angle. Above all those special designs is to enhance the content of the test and many experimental verification. This prototype takes a number of pilot studies of dissolved gas flotation system different intake, and compares grid plate angle of the flow pattern of the flotation tanks flotation tanks and so on. The results show that:the flotation pool can effectively reduce the regurgitation of the flotation zone and the dead zone, the flotation tank space to take full advantage of the reasonable structure of the flotation tank designed in accordance with the results of theory and simulation analysis also verify the correctness of the theoretical model.Through a systematic study of the subject, a number of useful conclusions were drawn, it provides the practical value of the research results for engaged in the pressurized air flotation system designers, and gives the future direction of research and development.