| Water is very important for the survival of human society. It is also an important factor related to the sustainable development of society. Water shortage and water pollution are very serious in China. Water shortage and water pollution has led to widespread water crisis. Protection of water resources and controlling water pollution has become a global problem. Therefore, researching and developing new technology of sewage treatment has become an urgent task of environmental researchers.Vermibiofilter is a novel technology for ecological wastewater treatment. It has gained more and more attention from domestic and foreign researchers recently, due to its simple tenchnics, low construction cost, high treatment efficiency and sludge-free property. The current vermibiofilter is usually packed filler in a container, the sewage is purified when flows through the filter. The thickness of filling is above 70 to 80 centimeters, generally no more than 1m. There are some inadequacies: in general, Earthworms only live in the upper filter media about 30cm from surface. Because there is no earthworm activity and less micro-organisms, removing of organic matter mainly occurred in the upper filter. Thus the treatment efficiency of lower filtration is low. It will make against to sewage discharge, bio-processing or utilization. In order to overcome these shortcomings, in this paper, we improved present vermibiofilter, designed a new type of multilayer vermibiofilter, so that the supply of oxygen is sufficient in filter, and it can improve pollutant removal efficiency.In this paper, the effect of multilayer vermibiofilter under high and low organic load was studied. It is showed that the system for COD, NH3-N, TP and SS remove are efficient both in high organic load and low organic load conditions. It is showed that average removal rate of the four indicators are 86%, 70%, 67%, 91% and 85%, 73%, 69%, 92%, respectively, both in high organic load and low organic load. Filter module of each layer is very effective in removing contaminants and pollutant concentration of output became lower layer by layer. Moreover, the quality of output is stable. input has a little impact on output.In this article, we compared multilayer vermibiofilter with common bio-filters. In another experiment we use two different kinds of fillers to compare their treatment effects. In this experiment, one is filled by peat, pine bark, earthworms and other organic filler, and the other is filled by ceramic, volcanic rock and gas block of ceramic tiles and other inorganic fillers. It is showed that multilayer vermibiofilter is much better than another filter in COD and NH3-N removal effect. However, multilayer vermibiofilter is worse in TP removal. The organic filler is weaker in phosphorus adsorption capacity than air bricks and other inorganic fillers.The paper study on earthworm population in high organic load too. During two weeks from beginning to get to stabilize, the population of adults, sub-adults, juveniles and cocoons are increase at the beginning and get a balance in the end. There is a good pertinency between the removal rates of contamination and the population.The system has good treatment efficiency. It has advantages of high efficiency, low cost and easy to management.
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