Research On Efficiency Of Areation And Its Effecting Factors With Multi-Grade Drop-Aeration Process

With the development of economic construction in china, the construction of small towns and new rural has made significant socio-economic effect. But in the same time, environmental issues have become increasingly prominent. There are enormous pressure on sewage treatment in rural and small towns.Multi-grade drop-areation biofilm process is a new sewage treatment process which developed to address this situation, This paper studies the drop-areation oxygenation process. The efficiency of areation and its effecting factors were discussed, and made proposals to the design of drop-areation device. We using self-made sewage experimented indoor, reached the following conclusions:Using Na2SO3 to eliminate oxygen dissolved in water, and add CoCl2 as catalyst, is a good simulation to sewage. The Na2SO3 amount of the needs is: 7.875mg per 1mg DO, and CoCl2 is need to meet the cobalt ion concentration of 5 mg/L.Drop-areation is a viable oxygenation method, and the effecting factors of the aeration efficiency mainly relatives to the following three factors: the aperture of drop-water hole in the drop-water plate, the spacing between two adjacent drop-water holes, and the height of drop-areation.The smaller the aperture of drop-water hole is, the better efficiency of aeration we have, but under normal circumstances, the best range of the aperture of drop-water hole is about 3.0mm~4.0mm. While the spacing between two adjacent drop-water holes are about 2.0mm, its effluence to the efficiency of aeration are less than 10%. So the best range of the spacing between two adjacent drop-water holes should longer than 2.0mm. Height of drop-areation is the most important effecting factors of the aeration efficiency, if the spacing is 2.0mm, the dissolved oxygen can reach 7~8mg/L when the height of drop-areation is no less than 1600mm. If the spacing is about 3.0~4.0mm, it is better to set two drop-water plate. The distance between to drop-water plate is about 1000~1300mm.When this process be used in practice, there are something important should be considered: the pretreatment of sewage, the design of the drop-water hole should be easy switch, and to reduce secondary pollution.This paper is basis on simulate experiment indoor, so, it is better to do further experiments to get data that closer to the actual situation if permitted.