| Ammonia,When applied to the micro-polluted water treatment, biological aerated filtercan be used as the pretreatment of the conventional process or depth treatment technology.Found in engineering in the long run, however, due to the larger thickness of the filtermaterial, which is difficult to expand in the process of washing filter, and after long running,there will be much sludge in filter material layer, which always leads to the hardening of filter,the increasing of head loss year by year and biological efficiency that has trended down overthe years.In order to solve the above technical defects, this task is to develop a double filtermaterial of aeration biological filter, by changing the structure of filter inherent, moving upthe position of the filter plate and setting stainless steel mesh in the under layer of the filter.As for filter material, we choose two filter material, suspended ceramsite placed between theunder layer stainless steel mesh and filter plate and activated carbon placed on filter plate.Filter adopts up-flow to water flooding, first through the biofilm on suspended ceramsitesurface to preliminary biochemical treatment of water, removing ammonia nitrogen, organicmatter, and most of the intercept water turbidity, and then through the upper layer of activatedcarbon advanced treatment, further removal of soluble organic matter, smell and material, etc.,improving water quality.We choose XiCun water source to conduct experiments to compare suspended ceramsite-activated carbon double-layer filter of packing and new expanded bed charcoal filter.Through contrast test, test carbon filter layer of turbidity and head loss during the same period,determine the parameters for the process operation and provide the process operationparameters and process parameters for engineering design. Make the new water purificationprocess should be able to represent our country city tap water production technology level,and change trend of XiCun water quality and constantly adapt to domestic and drinking waterhygiene standards. Aiming at the status of the Pearl River Delta water sudden pollutionfrequently accident, we test two new carbon filters to compare their capacity to it. The result shows that:(1) It was by suspended ceramsite-activated carbon aeration biological filter that solvedthe problems of traditional activated carbon–sand filter，such as, difficult flushing，compacting of the filling，over-turbidity of the carbon filter inlet and the weak strain capacity.The optimum operation parameters for the suspended ceramsite-activated carbon aerationbiological filter was upper aeration, with the gas water ratio being0.3. Backwashing was setas two stages: the first stage was gas and drainage, impact strength was5L/(m2s), in thisprosess，the ceramsite bed got completely fluidizated. The second phase was combinedgas-water flushing stage, intensity of water and gas were15~20L/(m2s) and12~15L/(m2s)respectivly, lasted for about10min, and the carbon bed in complete fluidization state，with atube into the carbon bed which can achieve the filter plate.(2)The turbidity removal rate Up-flow Microdilatancy BAC Process was only8%，conducive to extend the backwash cycle，and the effluent turbidit of suspended ceramsite-activated carbon aeration biological filter was low, which would affect the subsequent sandfilter. The removal rate of COD was higher than that of the latter. Instead, for the lack of DO，the ammonia nitrogen, nitrite removal rate was lower. With the rising rate of filtration, thesuspended ceramsite-activated carbon aeration biological filter had remained stable provingon the removal effect of turbidity and nitrite.(3)The suspended ceramsite-activated carbon aeration biological filter had straincapacity for high turbidity and ammonia sudden polluted water. Experiment result showed, asthe turbidity increased to4.0-5.0NTU, ammonia nitrogen threshold for the1.28mg/L, it stillcould achieve the "double standard", however, Up-flow Microdilatancy BAC Process wasunable to achieve the "double standard". |
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