| In this study a kind of low carbon environmental protection bio-trickling filter is self-designed and improved based on common bio-trickling filters designed by other researchers with a combination of the quality and quantity characters of the agritainment restaurant wastewater in southwest China tourism villages and landscape characteristics. This bio-trickling filter is aimed to solve problems brought by agritainment restaurant wastewater efficiently based on energy-saving, environmental protection, high efficiency and stability, and simple operation.This research consists of4parts:fillers screening, the startup of the reactor, the effect of hydraulic loading and the structure of reactor optimization, optimal inlet water load. Firstly, three kinds of fillers are screened out to be filled in different layers of bio-trickling filter from five kinds of fillers that with better adsorption capacity. The changes of pollutants and startup time were studied in the startup procedure after the normal start. Then the effect of restaurant wastewater treatment from water loading improvement is investigated, also nitrogen-density variation is tested along the bio-trickling filter and the factors that affect denitrification were analyzed, from which the bio-trickling filter was optimized. After that, the effect of restaurant wastewater treatment from different water loading is investigated, and the best water loading is concluded.In the process of fillers to screen, the particle size of3to5mm of zeolite, ceramsite, volcanic, shale and particle size of2to3mm of quartz sand were studied in the nitrogen and phosphorus adsorption test. It is found that unit mass filler for NH3-N and TP adsorption quantity increase with the concentration of the solution in the isothermal adsorption experiment of nitrogen and phosphorus with the fillers. In the model of the filler adsorption nitrogen phosphorus effects for linear fit, it was found that NH3-N and TP adsorption can be used Freundlich equations for linear fitting, and Langmuir equation to the TP adsorption for a better fit, but in the NH3-N adsorption effects, can be a better fit for other fillers other than shale. In the study of adsorption kinetics, zeolite can show the best effect of ammonia nitrogen adsorption, and volcanic show the best effect of phosphorus adsorption. After the overall evaluation, three fillers that would be filled in the bio-trickling filter were selected as zeolite ceramsite and volcanic sand.The change of pollutants concentration of inlet and outlet water and removal rate are studied in the process of the startup of bio-trickling filter. The results shown that membrane is formed in14days rapidly and effectively with a combination of artificial inoculation and natural inoculation. The improved bio-trickling filter run stably and the removal rate of COD and NH3-N can be stabilized over80%. TN is reduced to the rate of30%by conventional bio-trickling1#while the better rate above60%by improved bio-trickling filter(2#). However, the phosphorus removal rates in1#and2#are very similar to each other, with2#appearing no distinct advantages.In the experiment on the effect of treatment by bio-trickling filter with improvement of water hydraulic load, the treatment effects were compared at influent flow of8L/h and4L/h at the start. It is shown that,when the influent flow increased to8L/h, the COD and NH3-N removal rate of the improved bio-trickling(2#) reduces, but still at the high level, however the average removal rate of TN in2#which is higher than43.24%at the start. In the analysis of the concentrate of three kinds of nitrogen along the bio-trickling filter, more nitrite nitrogen accumulate lower at the bio-trickling filter, which is very related to low removal rate of TN. Therefore, close the intubation for oxygen at the lower layer of the bio-trickling filter(2#) to create an anoxic environment for the growth of denitrifying bacterias, which optimized the trickling filter.In the experiment on the effect of treatment by the bio-trickling filter with the structure optimized, the effect of the pollution treatment were studied and compared by the optimized bio-trickling filter with different water hydraulic load of8L/h and12L/h. It is shown that the optimized bio-trickling filter could process organics well above80%either at the fluent flow of8L/h or121/h, and at the same time it could improve the NH3-N and TN removal rate showing an obvious denitrification effect. The effect of COD and NH3-N removal is good at the fluent flow of8L/h, but is still lower than the same condition that before optimized. Especially TP reduced sharply because of nearly saturation of the absorption of fillers and the anoxic zone of the below layer of filter2#that is not suitable for the growth of phosphorus-accumulating bacterias. In conclusion, restaurant wastewater pollutants can be treated effectively by the self-designed, self-improved and easily assembled bio-trickling filter and optimized by closing all the intubations for oxygen at the lower layer of the improved bio-trickling filter. This kind of bio-trickling filter could make full use of mountainous terrain and is less occupied, lower construction cost and less energy consumption. It can also be oxygenated naturally and suited to the higher influent hydraulic loading rate of the restaurant wastewater from agritainment. The low carbon bio-trickling filter presents good application prospect on the processing of agitainment restaurant wastewater in southwest mountainous tourist villages. |
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