城市生活垃圾发酵增效及填埋场生命周期的研究

发布时间：2018-08-04 10:07

【摘要】：随着人口的增多以及生活水平的提高,城市生活垃圾堆积量增大,带来的一系列环境问题逐渐凸显。填埋处理是目前城市生活垃圾的主要处理方式。本文以无锡市某垃圾填埋场为研究对象,以提高垃圾填埋场发酵能力为目标,基于渗滤液水质和甲烷生成规律确定了垃圾厌氧发酵的最适温度;分析了回灌技术对垃圾渗滤液、甲烷生成和微生物群落结构的影响;对填埋场渗滤液水质、产气量变化规律进行预测,并利用物料平衡的方法分析堆体可降解有机碳量,确定了填埋场的生命周期。主要研究结果如下:分析温度对城市生活垃圾厌氧发酵的影响。以无锡市生活垃圾联合厌氧颗粒污泥发酵过程为研究对象,分析不同发酵温度(25°C、35°C和45°C)对城市生活垃圾厌氧发酵过程中渗滤液的化学需氧量(COD)、NH_4~+-N、挥发性脂肪酸(VFA)、渗滤液流出量和甲烷的影响。25°C、35°C和45°C的NH_4~+-N最终浓度分别为2450、2650和3000 mg·L~(-1),COD的去除率分别为60.9%、85.2%和80.1%,甲烷的平均体积分数分别为39.4%、66.9%和53.2%,累积甲烷量分别为15.44、100.95和75.89 m L·g VS~(-1)。结果表明35°C在缩短发酵周期,提高甲烷产量的同时,还能在一定程度上减小NH_4~+-N浓度,有助于减轻后续渗滤液处理的压力。探究了不同COD浓度渗滤液回灌对城市生活垃圾稳定性的影响。通过对不同COD浓度(3k、6k和9k mg·L~(-1))的渗滤液进行回灌处理,对发酵过程中的水质、产气变化进行数据跟踪,并且利用焦磷酸测序技术对其中的古菌群落进行了分析。结果表明,对照组、3k、6k和9k mg·L~(-1)回灌组COD的降解率分别为83.6%、85.7%、91.6%和80.8%;累积甲烷量分别为129.28、287.52、330.98和103.45 m L·g VS~(-1)。6k mg·L~(-1)回灌组的最高产甲烷速率比对照组、3k和9k mg·L~(-1)回灌组分别提高了91.7%、6.4%和126.8%。COD为6k mg·L~(-1)渗滤液回灌不仅能加速垃圾降解,还能显著提高填埋气产量。焦磷酸测序分析污泥中的古菌群落结构,结果表明高浓度渗滤液回灌会降低Methanobacterium、Methanoregula、Methanolinea、Methanospirillum、Methanosphaera的群落,对Methanobacterium的影响尤为显著,相对丰度仅为7.82%。而低中浓度回灌下的Methanobacterium相对丰度均在30%上下。填埋场预测模型的建立及生命周期分析。针对无锡市某垃圾填埋场渗滤液水质和产气量变化规律建立模型,获得COD、NH_4~+-N的浓度变化预测曲线。在Scholl Canyon模型的基础上对填埋场的产气进行预测,并确定了产气速率常数k为0.145。将预测数值与实际测量值进行了对比,平均误差仅在3.33%,结果表明模型是合理可靠的。通过有机碳平衡分析,确定封场时垃圾填埋场有机碳剩余量为266573.42吨。
[Abstract]:With the increase of population and the improvement of living standard, the amount of municipal solid waste is increasing, which brings a series of environmental problems. Landfill treatment is the main treatment of municipal solid waste. This paper takes a landfill site in Wuxi as the research object, aiming at improving the fermentation capacity of the landfill, based on the water quality of leachate and the law of methane generation, the optimum temperature of anaerobic fermentation of refuse is determined, and the effect of recharge technology on landfill leachate is analyzed. The effects of methane production and microbial community structure on landfill leachate quality and gas production were predicted. The biodegradable organic carbon content of landfill was analyzed by material balance method and the life cycle of landfill was determined. The main results are as follows: analyze the effect of temperature on anaerobic fermentation of municipal solid waste. The process of anaerobic granular sludge fermentation of municipal solid waste (MSW) in Wuxi City was studied. The effects of different fermentation temperatures (25 掳C ~ 35 掳C and 45 掳C) on the chemical oxygen demand (COD) of leachate during anaerobic fermentation of municipal solid waste (MSW), the effluents of volatile fatty acid (VFA),) leachate and methane (Ch _ 4) were analyzed. The final concentrations of NH _ 4 ~ -N at 25 掳C ~ 35 掳C and 45 掳C were 2450 ~ 2650 and 45 掳C respectively. The removal rates of 3000 mg / L ~ (-1) COD were 85.2% and 80.1%, respectively. The average volume fraction of methane was 66.9% and 53.2%, respectively, and the accumulative methane content was 15.44100.95 and 75.89 m L g VS-1, respectively. The results show that 35 掳C can shorten fermentation period and increase methane production, but also decrease NH4- N concentration to a certain extent, which is helpful to reduce the pressure of subsequent leachate treatment. The effect of leachate recharge with different COD concentration on the stability of municipal solid waste (MSW) was investigated. The water quality and gas production of leachate with different concentrations of COD (3kDa 6k and 9k mg / L ~ (-1) were tracked by recirculation, and pyrosequencing was used to analyze the community of ancient bacteria in the leachate of different concentration (3kg ~ (6k) and 9k mg / L ~ (-1). The results show that The degradation rates of COD were 91.6% and 80.8%, respectively, in the control group of 6k and 9k mg / L ~ (-1), respectively, and the accumulative methane contents were 129.287.52330.98 and 103.45 m L g VS-1 路6k / L ~ (-1), respectively, which were higher than those of the control group (3k and 9k mg L ~ (-1) by 91.7mg L ~ (-1) and 126.8%.COD of 6k mg / L ~ (-1), respectively. Filtrate recharge can not only accelerate the degradation of garbage, The landfill gas production can also be significantly increased. The results of pyrosequencing analysis showed that high concentration leachate recharge reduced the community of Methanobacteriumum Methanolineum Methanospirillum Methanosphaera, and the relative abundance was only 7.82%. The relative abundance of Methanobacterium was about 30% under low and medium concentration recharge. Establishment of landfill prediction model and life cycle analysis. A model was established for the variation of leachate quality and gas production in a landfill in Wuxi, and the prediction curve of CODU NH4- N concentration was obtained. Based on the Scholl Canyon model, the gas production of the landfill is predicted, and the gas production rate constant k is determined to be 0.145. The average error is only 3.33. The results show that the model is reasonable and reliable. Through organic carbon balance analysis, it is determined that the residual amount of organic carbon in landfill is 266573.42 tons.
【学位授予单位】：江南大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X799.3

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