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东北地区垃圾堆场的垃圾降解行为及稳定化研究

Study on the Waste Degradation Behavior and Stabilization of Dumping Sites in Northeast China

【作者】 谢冰

【导师】 刘惠玲;

【作者基本信息】 哈尔滨工业大学 , 环境科学与工程, 2010, 博士

【摘要】 目前,垃圾堆场在我国的垃圾处理方式中仍占很大比例,我国大多数城市周围都存在着垃圾堆场。这些垃圾堆场不仅占用大量土地、经常发生火灾和爆炸等安全事故,而且对环境的污染与影响非常严重。本文以哈尔滨市为例,通过模拟试验和现场采样分析,对东北地区城市生活垃圾堆场中固体垃圾的有机质、生物可降解物(BDM)、总糖、粗纤维及重金属等指标和垃圾渗滤液水质(COD、BOD、可生化性和氨氮)随时间的变化规律以及垃圾堆场的稳定化状况进行了一系列深入的研究,建立了垃圾渗滤液和固体成分各个指标的动力学模型,分析、比较了影响垃圾稳定化的关键因素,并据此对哈尔滨市的垃圾稳定化时间进行了预测。同时,本文还利用基因扩增——变性梯度凝胶电泳(PCR-DGGE)技术对模拟堆场条件下的微生物群落结构进行了研究。现场试验部分分别采集了哈尔滨市的四个垃圾堆场的垃圾,并且对不同堆放时间的垃圾中有机质、生物可降解物、总糖和粗纤维以及重金属等指标进行分析,研究各个指标与堆放时间的关系。结果表明:垃圾在堆放10年后,垃圾中有机质、BDM、总糖、粗纤维分别减少了50.77%、43.34%、83.38%、24.49%。通过对东部垃圾场和王岗垃圾场的垃圾进行挖掘试验,对两个垃圾堆场的不同堆放深度的垃圾中有机质、生物可降解物和重金属等指标进行分析,研究各个指标与堆放深度之间的关系。结果表明:固体垃圾有机质、BDM、总糖和粗纤维随垃圾堆放时间的增加而呈现降低的趋势,垃圾中有机质和BDM降解速度随垃圾堆放的深度增加而减缓。通过实验室模拟试验研究环境温度对生活垃圾降解的影响,模拟试验温度控制在40℃条件下其垃圾渗滤液各指标和固体垃圾成分各指标达到最大值需要的时间分别比19℃条件下缩短10天和10~20天,结果表明试验范围内环境温度的升高可以缩短垃圾降解的启动时间。实验室模拟试验中40℃试验组的垃圾中有机质和BDM降解率分别是19℃试验组降解率的1.41倍和1.22倍。论文通过模拟垃圾堆场试验对不同环境条件下垃圾堆场中的垃圾降解行为进行了研究,结果表明:自然环境条件试验的渗滤液和固体成分指标的降解速度均比人工模拟条件试验装置快。自然环境条件下垃圾渗滤液的COD、BOD的降解率以及氨氮的转化率分别是人工模拟降水条件试验降解率的1.39倍、1.10倍和1.60倍;自然环境条件下垃圾中有机质、BDM的降解率分别是人工模拟降水条件试验降解率的1.29倍和1.60倍。通过对比分析发现,除环境温度外,天然降水、营养物质和溶解氧、微生物以及降解过程中释放的热量散失等因素对垃圾渗滤液和固体垃圾中有机质和BDM的降解均产生重要影响。利用PCR-DGGE技术,对人工模拟条件试验装置和自然环境条件试验装置的两个垃圾层内的微生物群落结构进行了研究,结果显示两个模拟试验装置内均有着比较丰富的细菌群落多样性。四个不同样品内存在共同的菌种,而每个样品又存在各自比较优势的菌种。通过DGGE图谱的丰富度分析,发现自然环境条件试验装置内的菌群多样性明显高于人工模拟降水条件试验装置,而下层垃圾堆层的菌群种类多于上层垃圾堆层。通过DGGE图谱的相似性分析,发现人工模拟条件试验装置与自然环境条件试验装置内的微生物由于所处的大环境不同,导致微生物种群差异很大。但随着堆放深度的增加,不同垃圾堆体内菌群相似性却明显随之增加。基于生化反应的动力学方程?C?? C e?Kt 0,对模拟试验、垃圾堆场试验的垃圾渗滤液和固体垃圾成分各指标随堆放时间的变化情况进行数学拟合,得到各指标的反应动力学拟合方程,并且得出哈尔滨的渗滤液达到稳定化(COD≤100mg/L,BOD≤30mg/L,氨氮≤15mg/L)所需要的时间为11年,固体垃圾指标达到稳定化(有机质≤7%,BDM≤5%)所需要的时间为19年。本研究成果对控制生活垃圾堆场的环境污染、采用生物强化技术加速垃圾堆场的稳定化、以及加速垃圾堆场土地的再利用具有重要的理论意义和实用价值。

【Abstract】 At present dumping sites takes up a great proportion in waste treatment method proves. There is a large number of life dumping sites in the vast majority of cities around of China. Not only lots of lands were occupied by dumping sites, but also many events such as fire hazard and explosion often occur in dumping sites. Meanwhile, environment was polluted and impacted very seriously by dumping sites.In this paper, Harbin City as an example, we studied on the variation of indexes, such as organic matter, bio-degradable materials(BDM), total sugar, crude fiber, heavy metals and other water quality indicators and landfill leachate(COD, BOD, Bio-degradability and ammonia nitrogen) of solid waste in the life dumping sites of municipal solid waste in northeast regions with the time passing by and studied deeply on the stabilization of the dumping sites through simulation experiments and field sampling and analysis; built dynamic models of landfill leachate and each index of solid components; analyzed and compared key factors influencing on stabilization of waste and accordingly predicted stabilization time of waste and studied on microbial community structure in the dumping sites condition by use of polymerase chain reaction - denaturing gradient gel electrophoresis (PCR-DGGE) technique.We collected waste of these four dumping sites in Harbin, and analyzed organic matter, bio-degradable materials, total sugar and crude fiber, as well as indexes of heavy metals, and studied the relation between each indicator and stacking time. The results showed that organic matter in solid waste, BDM, total sugar and crude fiber had reduced by 50.77%, 43.34%, 83.38% and 24.49%, respectively after 10 years waste was dumped. We also analyzed the indexes, such as organic matter, bio-degradable materials and heavy metals in waste piling up in the different depths of these two dumping sites through excavation test in the Dongbu dumping site and the Wanggang dump site, and studied the relation between each index and stack depth. The results showed that the content of the components of solid waste decreased with the increase of stacking time and increased with the increases of stack depth. We studied the influence of environmental temperature on degradation of the waste through simulating test. The time that used for indexes of landfill leachate and solid components achieving maximum value when temperature of simulation experiments was 40℃were shortened by 10 and 10~20 days than those at 19℃, respectively. The results showed that starting time of waste degradation was shortened under higher temperature (in the range of test). In the accelerated simulating test, the degradation rate of organic matter and BDM index in solid waste at 40℃was at 19℃1.41 and 1.22 times, respectively. The results showed that waste was easier to degrade with higher temperature.In this paper, waste degradation of dumping sites in different environmental conditions was studied through simulation dumping sites tests. The results showed that the degradation of landfill leachate and solid components indexes under natural environmental conditions test device were faster than those under artificial precipitation conditions simulation experimental setup. The degradation rate of COD, BOD and conversion rate ammonia nitrogen of leachate under natural environmental conditions test device was 1.39, 1.10 and 1.60 times those under artificial precipitation conditions simulation experimental setup, respectively. The degradation of organic matter and BDM index in solid waste under natural environmental conditions test device was 1.29 and 1.60 times those under artificial precipitation conditions simulation experimental setup, respectively. Though the analysis and comparison, it is founded that the ambient temperature was not the only critical factor to affect the rate of waste degradation. Some factors such as rainfall, nutrient substance, dissolved oxygen; micro-organisms as well as dissipation of released heat in the process of degradation had much important influence on the degradation of landfill leachate, organic matter in solid waste and BDM.We studied the structure of microbial community structure in two different waste layer of artificial precipitation conditions simulation test and natural environmental conditions simulation test by use of PCR-DGGE technology. The results showed that there are rich diversities of microbial communities in these two simulation test devices. The common bacteria existed in four different samples and there were respective comparative advantages bacteria also existed in each sample. It could be seen that diversities of microbial communities of natural environmental conditions simulation test device were better than those of artificial precipitation conditions ones, and the microbial types of the lower layer of trash were more than those of upper’s through abundance analysis of DGGE spectrum. It was found that there is great difference between microbial community under natural environmental conditions and that under artificial precipitation conditions because environment for microorganism growth is different through similarity analysis of DGGE spectrum. Similarity of microbial communities in different waste dump increased obviously with stacking depth.Based on biochemical reaction kinetics equation,we carried outmathematical fitting of the changes that landfill leachate and solid comPonents ofall indexes of simulated landfill test and simulated dumP test with time Passing by,and got kinetics fitting equation of each index,and concluded that the required timeof leachate of the dumPing sites in Harbin to achieve stabilization(COD≤100mg/L,BOD≤30mg/L,arnrnonia nitrogen≤15mg/L)was 11 years and the required time ofsolid waste indicators of the dumP in Harbin to achieve stabilization(organicmatter≤7%,BDM≤5%)was 19 years.In sununary,we studied landfill leachate,waste of organic matter,BDM,totalsugar,crude fiber and heavy metals of the dumPing sites in Harbin,and the detailsof thes加cture of microbial PoPulations in every waste layer,and further studiedthe stability Process of the dumPing sites.These results Provided a strongtheoretical basis for reuse of the future dumPing sites.

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