| Humified media Filter constructed by humified filler is a new decentralized treatment structure. At present, Humified media Filter has been put into practical application of sewage treatment. However, two defects appeared in the running process. The one is the low total nitrogen removal efficiency, and the other is the large cover area. To solve the above problems, macro and micro indicators were investigated to establish an evaluation system. Also, COD removal efficiency and biomass in the filter were surveyed to tell out characteristics of organic matter removal. At last, a dynamic model was built. All the experiments are beneficial for the theory system setting up, which will serve for the filler modification and process optimization in Humified media Filter.Studies on Humified media Filter were carried out from four aspects:analyses on micro structure of filler, comparison of saturated hydraulic permeability coefficients, degradation characteristics of COD removal and the dynamic model building. The key findings are outlined below.SEM images showed that aged refuse and peat were constituted of reunion bodies with three-dimensional space structure. Coal and sand which had less rough surface mainly were made up of small particles. XPS maps displayed that Si, C, O and V could be found on all the four kinds of filler. Besides, K could be found in aged refuse, A1 and Zn in peat, and Zn and K in sand. FT-IR analyses told out the hydroxyl, vinyl compounds and Si-O-Si group's existence in all the four kinds of filler. Specific surface area from high to low was in sequence of peat, aged refuse, coal and sand. And CEC was in the descending order of aged refuse, peat, coal and sand. Combing microstructure analyses, peat and aged refuse are more suitable for Humified media Filter.Saturated hydraulic permeability coefficients were measured under clear water and simulation wastewater. All the four biofilters displayed very high saturated hydraulic permeability coefficients under clear water. The descending sequence is peat, aged refuse, coal and sand. Saturated hydraulic permeability coefficients of each biofilter all plunged under the simulation wastewater, keeping the same order with that under clear water. The organic matter removal efficiency, biological species and biomass are investigated to make clear the characteristics of organic matter removal. Three kinds of microorganism were found in all four biolfilters, which played a main function in the organic matter degradation process. In laboratory research, all the biofilters filled with aged refuse, peat and coal displayed ideal organic matter removal rates when inlet concentrations were 500mg/L and 1000mg/L. In contrast to the other two biofilters (aged refuse and coal), the organic matter specific removal rate of biofilter filled with peat was lowest, and the hydraulic permeability coefficient was highest, which leads to the minimum blockage. Biofilter filled with peat was most likely to run stably in long-term, and peat was proved to be excellent humus filler.Through the operation of completely mixed system and Humified media Filter, a dynamic model was built. Half rate constant Ks and maximum specific degradation rate Vmax are obtained from completely mixed system according the Monod mode. The half rate constant Ks equals to 178.6mg/L, and the maximum specific degradation rate Vmax was 1.29X 10-4d-1. The dynamic model of Humified media Filter could be expressed by the equation of Se/So= exp(-2.04 x 10-9 C/F). |
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