| Sanitary landfill is the most effective and economical way for solid waste disposal, but some environmental problem exists, like the complicated leachate quality and difficult to treatment, the gas-producing periods as well as long time lasted, smaller gas production and uneasy collection, etc. The bioreactor landfill technology combines refuse retention, pollution partition and biodegradation, etc. to the landfills while no effective technology has been found for the leachate pollution. The project team members combine the bioreactor technology with the disposal function of mineralized solid waste bed towards leachate in order to make an anaerobic-semiaerobic bioreactor landfill. Based on three analog device (large type1#for anaerobic bioreactor control group, the la2#,3#for anaerobic bioreactor+quasi aerobic mineralized refuse bioreactor bed model control group), the study the gas production and the gas component variation at the later stage of the column anaerobic unit, at the same time study regulation of solid waste degradation.During the experiment, the biogas production rate, the methane volume percentage and the cumulative gas production of the three anaerobic unit shows that1#>3#>2#, it indicates that after the semi-aerobic refuse bed in a series, it. will restrain the gas production. As part of the organics of the anaerobic unit will be removed in SAARB by the leachate recharge, which reduce the amount of organics to gas phase in ANBL. On the other hand, leachate will be reaerated after the SAARB treatment, and then is recharged to ANBL, this will inhib it the activity of anaerobic bacteria. Seeing from the3#>2#, we can know that the increase of the leachate recharge rate will help to gas production, and the water content of rubbish will play a decisive role in the methane production in landfills.The relationship of the accumulative settlement for anaerobic unit in month0-13is1#>3#>2#, and3#>2#>1#in month13-16. Analyzing the initial landfill height of various anaerobic units, as well as whether the quasi-aerobic mineralized refuse and the recharge rate is in a series, it shows that refuse degradation is compression settling based in earlier phase, while biodegradation settlement in the later phase, besides, the series of semi-aerobic waste bed and the higher recharge frequency can accelerate the waste degradation. Although the organic matter of the biodegradable degree for the characterized refuse as well as the BDM will be greatly influenced by the nonuniform sampling,20months later it will show a downward trend.Comprehensively analyzing of the methane volume percentage of gas producing, the COD value in leachate and the leachate pH value trend, we can judge that the methane fermentation stage of three anaerobic simulation columns are respectively705d,690d～and660d. It shows that AN-SABL can help to reduce the phase period of landfill hydrolysis acidification, speed up the time for ANBL into methane fermentation, and the recharge frequency of3d/t is more favorable. According to the data of accumulative methane quantity produced by anaerobic column based on experiment, the exponential growth model is established, and there are significant correlations between this model and measured data.The thesis is a good attempt on anaerobic-semiaerobic landfills; the experimental results can provide reference for the practical application of the anaerobic bioreactor and semi-aerobic mineralized refuse bioreactor. |
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