Study On Efficiency Of Aeration Type In Biological Aeration Filter In Treating Wastewater

Biological aerated filter is a new technology of wastewater treatment. Scholars national and abroad have researched the factors like temperature, water quality and pH value. They have made agree with each other on all of these points, however, researches on the movement law for gas-liquid two-phase flow in biological aerated filter is lack, the oxygen transfer efficiency, momentum and energy between phase as well as the interaction among turbulent components are all unclarified, applications of biological aerated filter also need theory, so it is especially essential to measure the velocity field. This research begins with parameters of two-phase flow and establishes the influence of aeration type in treating wastewater by means of the combination of experimental research and numerical simulation on the gas-liquid two-phase flow.This paper designed a set of biological aerated filter. Particle Image Velocimetry technique was used to study gas-liquid two-phase flows. Take the bubble velocity as a boundary condition, gas-liquid two-phase flow velocity field of different conditions obtained. Measured chemical oxygen demand at specific moment, results of numerical simulation was verified. Finally this paper proposed the most effective aeration pattern.The main results in this paper are listed as follow:(1) Researches about two-phase flow can begin with parameters, particle image velocimetry technique method can be used to complete the numerical simulation.(2) FLUENT software simulated two-phase flow velocity field accurately. The resultsconsistent with experiment.(3) With the change of diameters of capillary tubes, bubble velocity, ratio of aeration tank et al, bubble volume and distribution of gas phase changed simultaneously.(4) When the ratio of aeration tank h/w=1, diameter of capillary tubes is smallest, the bigger the bubble velocity, the two-phase gas-liquid mixing more strong, turbulent intensity getting bigger, more fully makes gas-liquid mass transfer, the higher the efficiency of sewage disposal we can get.