Study On Self-aerated Multilayer Bio-contact Oxidation Process

Among many research of sewage treatment process with lower cost, the drop aeration is drawing due to its simple devices and lower treatment cost. The self-aerated multilayer bio-contact oxidation process tested herein is used to treat mid-low concentration sewage by the drop aeration oxygenation combating with biological contact oxidation, effluent recycling buildup to increase dissolved oxygen content and make drop aeration in application of more water quality. The test on self-oxidation contact filter independently developed to simulate sewage treatment and the main contents of research: to discuss the influences on the treatment effect by comparing with the two water distributing devices; to discuss the influence on the treatment effect under intermittent and continuous operation separately; to determine which filler is conditioned in application of drop aeration process, combined filler and elastic solid filler; to determine the recycling flow's influences on the treatment effect. Based on the above, the conclusions are as follows:Films grow slowly in filter in natural method at the beginning of biofilm culturing, and sludge deposit is not easy so it can be applied in the process of drop aeration; increasing the numbers of holes on water distributing devices will improve the distributing uniformity and dissolved oxidation effect: the recycling flow increase will benefit dissolved oxidation increase to improve the treatment effect, but it will have an different treatment effect on COD, NH3-N in continue operation. It will not improve the treatment effect on COD greatly when recycling flow is at 300L/h or greater, but it can greatly improve the treatment on NH3-N; the treatment effect in continue operation is better than that in intermittent operation. The filler is filled with combined fillers tested and operates continually, with recycling flow at 400L/h and HRT 8h, the concentration of COD and NH3-N in effluent meet the discharge standard, but the concentration of NH3-N is higher in intermittent operation; the fillers to be selected in application in the drop aeration process need to have larger specific surface area. The most important is to have biofilms distributed in filter uniformly. This will benefit the mass transfer process of oxygen, pollutants and biofilms.