【作者】 李启彬；

【导师】 杨立中；

【作者基本信息】 西南交通大学 ， 市政工程， 2004， 博士

【摘要】 传统的垃圾卫生填埋场具有填埋垃圾稳定速率慢、渗滤液难处理且费用高等不足，生物反应器填埋场不仅能加快填埋垃圾的稳定进程，还能减少渗滤液的排放量和污染强度，是一种极具发展潜力的城市垃圾处理方式。作为最主要的一种控制措施，渗滤液回灌能大大加快生物反应器填埋场的稳定进程。本文即以渗滤液回灌为主线，研究它在厌氧型生物反应器填埋场快速稳定进程中的影响和作用。 本文通过模拟实验首次系统地研究了不同回灌方式(不同回灌频率、回灌量和回灌速率)下渗滤液在不同填埋垃圾(不同垃圾密度和厚度)中的运移和滞留特征；对比研究了不同渗滤液回灌频率对厌氧型生物反应器填埋场启动和稳定进程的影响，并以实验成果为依据，在全面利用填埋垃圾固相可降解有机物量、渗滤液COD浓度和产甲烷速率三方面信息的基础上，建立了厌氧型生物反应器填埋场稳定的动力学模型。针对厌氧型生物反应器填埋场运行后期渗滤液COD浓度衰减慢、氨氮浓度长期偏高的不足，首次提出通过改变运行方式来加速其稳定进程的理念，并在室内模拟实验中得以成功实施。 通过回灌渗滤液水力特性实验研究表明：①填埋垃圾的有效贮水率是渗滤液回灌方式和环境温度的函数。回灌频率越高，回灌量越多，回灌速率越慢，填埋垃圾的有效贮水率就越高；填埋垃圾有效贮水率与环境温度基本符合负线性相关关系，温度越高，填埋垃圾的有效贮水率越低。由于温度降低时填埋垃圾的有效贮水率反而增加，加之低温时微生物降解填埋垃圾的活动有所减弱，对水分的需求也相应减少，因此在低温环境中适当降低渗滤液回灌频率、减小回灌量不会导致填埋垃圾含水率过分下降。②回灌渗滤液的非均匀流在渗流前期占主导地位，但低频率、大水量、低速回灌以及较高的垃圾压实密度、较大的垃圾厚度使渗滤液运移相对均衡。在综合考虑不同第日页西南交通大学博士研究生学位论文回灌方案对填埋垃圾有效贮水率和含水率变化的影响后，实施高频率、大水量、低速率回灌更有利于改善填埋垃圾的含水率分布。 对厌氧型生物反应器填埋场启动的实验研究显示，在调节回灌渗滤液pH值的条件下，回灌频率越高，厌氧型生物反应器填埋场较传统填埋场先开始产甲烷，但当回灌频率在3d/次以上时，两者开始产甲烷的时间相差无几。综合考虑启动周期和运行费用等因素，认为在厌氧型生物反应器填埋场启动阶段实施3d/次的渗滤液回灌频率较为合适。 模拟实验研究还表明，渗滤液回灌频率越高，厌氧型生物反应器填埋场稳定产甲烷速率越快，但产甲烷速率随回灌频率的提高而继续增加的幅度会逐渐减小。在填埋垃圾的稳定过程中，产甲烷速率快速衰减并不意味着填埋垃圾已得到更充分的降解。对厌氧型生物反应器填埋场稳定进程的判断需同时综合考虑渗滤液有机污染强度、产甲烷速率和固相垃圾变化等指标。 在充分利用填埋垃圾固相可降解有机物量、渗滤液COD浓度和产甲烷速率三方面信息的基础上，建立了厌氧型生物反应器填埋场稳定动力学模型，根据模拟实验结果对固相垃圾水解和产甲烷进程的相关参数进行了估计。在比较渗滤液回灌运行费用和填埋场提前稳定产生的经济效益后，在厌氧型生物反应器填埋场稳定期间施行Zd/次的渗滤液回灌频率经济效益最佳，然后是3d/次和ld/次的回灌频率，而回灌频率为o.sd/次时效益最差。 根据首次提出的改变厌氧型生物反应器填埋场稳定后期运行方式的理念开展的模拟实验，厌氧型生物反应器填埋场稳定后期按准好氧方式运行后，渗滤液COD浓度衰减速率提高约3倍，渗滤液氨氮浓度在较短时间内 (回灌频率为ld/次的180天，3d/次的360天)降到不能检出水平，色度明显改善，渗滤液很快(回灌频率为ld/次的205天，3.5d/次的360天)达到国家二级排放标准要求。按准好氧方式运行时，较高的渗滤液回灌频率更有利于渗滤液水质的快速改善。关键词:厌氧型生物反应器填埋场;启动;稳定;渗滤液回灌;动力学模型更多还原

【Abstract】 While traditional municipal solid waste (MSW) landfill has some disadvantages as long stable period, difficult and expensive for leachate treatment, the bioreactor landfill can not only accelerate the stabilization of landfilled waste, but also cut down the quantity of leachate and reduce its pollutant intensity, so it will be a competitive way to treat MSW in the future. Leachate recirculation, as one of the leading control measures, can accelerate the stabilization of bioreactor landfill and this paper focuses on this point.By means of simulated waste columns with different density and thickness, the characteristics of the movement and storage of recirculated leachate in waste was first studied in a systematic way for different leachate recirculation modes (different recirculation frequency, quantity and rate). The influence of different leachate recirculation frequency on the start-up and stabilization of anaerobic bioreactor landfill was also studied. Based on the experimental results, the kinetics model of stabilization of anaerobic bioreactor landfill was developed after the quantity of degradable solid organic waste, the leachate COD concentration and the rate of methane production in the landfill were taken into account comprehensively. In view of slowly-dropped COD concentration and the higher-kept ammonia-N concentration in the leachate in the late stabilization stage of the landfill, the idea to change its operation mode was brought forward and put successfully into practice in simulated experiment.It was shown from the experiment on the hydrodynamic characteristics of recirculated leachate that: (1) the effective water storage capacity of buried waste is a function of the leachate recirculation mode and environmental temperature. The higher recirculation frequency, the more recirculated leachate quantity and the lower recirculation rate, the higher the capacity is. The capacity changes with temperature as negative linear relationship, that is, the higher temperature, the lower capacity is. As the capacity of the waste increases with the temperature drop, at the same time, the action of microorganism starts to weaken and its requirment for the moisture becomes less, the frequency and quantity of leachate recirculation reduced properly in the environment of lower temperature will not result in the too much moisture drop. (2) Non-uniform flow prevails over the earlier stage seepage of recirculated leachate. However, the leachate recirculation with a low frequency, large quantity and small rate, the big waste density and thickness may leads to more uniform seepage. After the influence of different leachate recirculation modes on the capacity and the water moisture of the waste were fully taken into account, to recirculate leachate at high frequency, large quantity and lower rate is more favourable for improving water moisture distribution in the waste.It was shown from the simulating experiment on the start-up of anaerobic bioreactor landfill that the landfill generates methane earlier if leachate recirculation frequency is higher under the condition of adjustment pH of leachate before recirculation, but there was not much difference if leachate recirculation was implemented once every 3 days. Considering the time and the expenditure in the start-up period, the best frequency to recirculate leachate is once every 3 days for the start-up period of anaerobic bioreactor landfill.It was also indicated from the experiment on the stabilization of anaerobic bioreactor landfill that the rate of methane production finds the faster, the higher leachate recirculation frequency, but the rate will rises in a more smaller manner with the higher leachate recirculation frequency. During the stabilization of the landfill, the quickly-dropped rate of methane production does not means that the waste has been degraded well. Determination of the stabilization process of the landfill requires to take fully account of the organic pollutant strength of leachate, the rate of methane production and the degradation extent of organic so更多还原