生活垃圾填埋场春夏季CH4释放及影响因素

采用静态箱法监测了2个生活垃圾填埋场春、夏季及昼夜的CH₄释放通量,并分析了影响CH₄释放的相关因素. 结果表明:填埋气体(LFG)主动收集对填埋场CH₄释放的影响显著. 在填埋龄相近的条件(4.0～4.5年)下,无LFG主动收集的填埋场春、夏季CH₄的释放通量(以CH₄计)平均值〔(541±1　005) mg/(m2·h)〕比有LFG主动收集的填埋场提高4.4倍. 在有LFG主动收集的填埋场内,填埋龄为1.0～1.5年的非渗滤液灌溉区的CH₄释放通量均值〔(324±847)mg/(m2·h)〕为灌溉区的10.0倍左右. 在有LFG主动收集的填埋场内,CH₄释放通量与各环境因子间无显著相关;而在无LFG主动收集的填埋场内,CH₄释放通量分别与覆土温度和气温呈显著正相关,与大气压强呈显著负相关.相关性分析结果表明,CH₄释放通量与填埋场覆土中含水率,w(有机碳)和w(总氮)呈显著正相关.      

硅氧烷在环境中的迁移转化及其对生物气应用的影响

近年来大量使用含有机硅氧烷材料造成硅氧烷作为污染物进入环境,数量逐年增加.在垃圾填埋场和污水处理厂消化产生的生物气(沼气)中出现的硅氧烷会在燃烧过程中结垢,十分不利于生物气的利用,必须清除.本文综述了硅氧烷的理化性质、在环境中的迁移转化规律与生物降解性能、在生物气中的浓度分布以及去除技术,并对生物气应用中的硅氧烷的控制对策研究作出展望.作者强调,需进一步深入研究硅氧烷的生物降解的机理.     

填埋垃圾和渗滤液中CH4氧化菌的丰度研究

应用实时荧光定量聚合酶链式反应(Real-Time Quantitative Polymerase Chain Reaction,简称实时荧光定量PCR)技术对填埋场垃圾和渗滤液中CH₄氧化菌的pmoA基因进行定量分析. 结果表明:实时荧光定量PCR技术可用于渗滤液和垃圾中CH₄氧化菌的定量分析. 对于厌氧和准好氧填埋,初期渗滤液中CH₄氧化菌的数量均高于稳定期;准好氧填埋体渗滤液中CH₄氧化菌的数量均高于厌氧填埋体. 准好氧填埋垃圾中CH₄氧化菌的数量随着填埋龄的增加呈先增加后降低的趋势,并在填埋后的9个月左右达到最大值,与准好氧填埋体CH₄产生的规律相似. 同时,准好氧填埋垃圾中CH₄氧化菌的数量随着距导气管距离的增加而降低,但不同填埋时期的变幅不同,与准好氧填埋体O₂和CH₄的迁移规律有关. 此外,对渗滤液和垃圾样品的研究表明,准好氧填埋体垃圾填埋层内部存在大量的CH₄氧化菌,具有显著的CH₄氧化能力.      

北京市安定生活垃圾填埋场VOCs恶臭物质及其臭气强度

挥发性有机物(VOCs)是填埋场重要的恶臭源之一.为了深入了解造成填埋场恶臭的VOCs及其臭气强度情况,在2014年7—8月采用固相微萃取(SPME)-气相色谱(GC)-质谱(MS)联用法测定了北京市安定生活垃圾卫生填埋场内各代表性地点的VOCs.共确认了48种化合物,包括烷烃、烯烃、芳香烃、环烷烃、萜类、酯类、醛酮类、卤代烃、醇类及含硫化合物和含氮化合物.烷烃的种类最多,达到13种,其次是芳香烃,为9种.以内标法和外标法相结合测定了其中35种物质的含量,发现浓度在0.05~40 mg·m~(-3)之间.在厂区入口和作业面浓度最高的VOC是2,2,4,6,6-五甲基庚烷,在沼气干管是甲苯.从实际经验和臭气强度出发,建立了一种恶臭物质筛选方法,即首先以检出频次和各地点浓度比值筛选出可能的恶臭物质,然后由臭气强度确定最终的恶臭物质.筛选结果表明,填埋场内的恶臭VOCs是对伞花烃、对二甲苯、乙苯、甲苯和邻二甲苯,其中对伞花烃和对二甲苯对恶臭贡献尤为显著.这些恶臭VOCs浓度之间呈现出显著的相关关系,表明这些物质均来源于填埋场内生活垃圾的降解过程.     

Minimizing N2O fluxes from full-scale municipal solid waste landfill with properly selected cover soil

Municipal solid waste landfills emit nitrous oxide （N2O） gas. Assuming that the soil cover is the primary N2O source from landfills, this study tested, during a four-year project, the hypothesis that the proper use of chosen soils with fine texture minimizes N2O emissions. A full-scale sanitary landfill, a full-scale bioreactor landfill and a cell planted with Nerium indicum or Festuca arundinacea Schreb, at the Hangzhou Tianziling landfill in Hangzhou City were the test sites. The N2O emission rates from all test sites were considerably lower than those reported in the published reports. Specifically, the N2O emission rate was dependent on soil water content and nitrate concentrations in the cover soil. The effects of leachate recirculation and irrigation were minimal. Properly chosen cover soils applied to the landfills reduced N2O flux.     

Minimizing N_20 fluxes from full-scale municipal solid waste landfill with properly selected cover soil

Municipal solid waste landfills emit nitrous oxide(N_2O)gas.Assuming that the soil cover is the primary N_2O source from landfills, this study tested,during a four-year project,the hypothesis that the proper use of chosen soils with fine texture minimizes N_2O emissions.A full-scale sanitary landfill,a full-scale bioreactor landfill and a cell planted with Nerium indicum or Festuca arundinacea Schreb,at the Hangzhou Tianziling landfill in Hangzhou City were the test sites.The N_2O emission rates from all test sites were considerably lower than those reported in the published reports.Specifically,the N_2O emission rate was dependent on soil water content and nitrate concentrations in the cover soil.The effects of leachate recirculation and irrigation were minimal.Properly chosen cover soils applied to the landfills reduced N_2O flux.     

南京轿子山生活垃圾填埋场温室气体释放的变化规律

垃圾填埋场是全球温室气体释放的重要来源. 在南京轿子山生活垃圾填埋场3个具有不同填埋龄(4~13 a)、覆土深度(30~100 cm)和有无填埋气收集系统的平台,采用静态箱气相色谱法对填埋场CH₄和N₂O的释放规律进行了研究. 结果表明:填埋龄与覆土深度对填埋场CH₄和N₂O的释放影响显著,与其他2个平台相比,填埋龄(10~15 a)长、覆土深度(80~100 cm)大且无填埋气收集系统的平台1的CH₄和N₂O四季及昼夜释放通量均相对较小,相差为2个数量级;虽然3个平台温室气体释放通量的昼夜和季节性变化规律并不一致,但在春季均出现最小值,CH₄和N₂O的最小释放通量分别约为30和186.49 μg/(m2·h). 夏季、秋冬季交替及冬春季交替时期,CH₄和N₂O的释放通量均出现峰值,晚上的释放量约占全天释放总量的70%左右. 垃圾填埋场是高度异质性体系,相关性分析表明,CH₄释放通量与覆土温度、覆土含水率无显著相关性,而N₂O释放通量却与这2个指标呈显著相关. CH₄释放通量季节和昼夜性变化较稳定,变异系数范围分别为13%~405%和43%~429%. N₂O释放通量的季节性和昼夜性变异水平较高,变异系数范围分别为15%~1 005%和17%~1 552%,因此有必要进行全时段监测.      

氨氧化菌对填埋场CH4协同氧化及铵抑制作用的研究

借助乙炔(C₂H₂)抑制和添加外源铵盐,采用批式培养试验,在初始CH₄浓度为16%的条件下模拟填埋场高CH₄浓度环境,通过分析样品中氨氧化菌对CH₄氧化的贡献率及铵对CH₄氧化的抑制率,研究了填埋场覆盖土、矿化垃圾、砂土和黏土中氨氧化菌对CH₄协同氧化及铵抑制作用. 结果表明:4种供试样品中氨氧化菌对CH₄氧化的贡献率在5.64%~16.24%之间,次序为砂土＜黏土＜覆盖土＜矿化垃圾,覆盖土中的贡献率为14.90%,比矿化垃圾低8.25%,填埋场样品(矿化垃圾和覆盖土)是一般土壤(砂土和黏土)的1.8~10.9倍. 铵对CH₄氧化过程的抑制率在11.90%~24.84%之间,次序为砂土＜黏土＜覆盖土＜矿化垃圾,覆盖土中为23.21%,比矿化垃圾低6.56%,填埋场样品是一般土壤的0.9~2.1倍. 填埋场样品中氨氧化菌对CH₄氧化的贡献率及铵对CH₄氧化的抑制率明显高于一般土壤.      

武进市夹山垃圾卫生填埋场的水环境影响与控制

卫生填埋是目前及今后相当长的时期内我国城市生活垃圾（MSW）处理的主要方式。但按我国卫生填埋技术、污染控制标准，目前国内尚没有垃圾填埋场能全部达到要求，多为准卫生填埋场。其运行后，对周围的大气及水体、土壤等环境将产生一定影响（污染）。本文以武进市夹山垃圾卫生填埋场为例，着重对填埋场运行后垃圾渗滤液等对周围地表、地下水环境的影响进行了分析评价，并提出了相关控制对策。     

Spatio-temporal variation of landfill gas in pilot-scale semi-aerobic and anaerobic landfills over 5 years

Variation of CH₄, CO₂, and O₂ concentrations in layers of different depths in semi-aerobic and anaerobic landfills was analyzed over a period of 5 years. The results showed that most of the municipal solid waste became basically stable after 5 years of landfill disposal. In the upper and middle layer, the concentration of CH₄ in the semi-aerobic landfill was significantly lower than that in the anaerobic landfill in different landfill periods, while in the lower layer, there was little difference in the CH₄ concentration between the semi-aerobic and anaerobic landfills. The average concentration of CH₄ and CO₂ in the anaerobic landfill was always higher than that in the semi-aerobic landfill, while the O₂ concentration showed an opposite variation in different landfill periods. This was related to the aerobic reaction of landfill waste around the perforated pipe in the semi-aerobic landfill, which inhibited effective landfill gas generation.     

有机垃圾填埋过程产甲烷量化模型研究

垃圾填埋场产生大量甲烷,收集这些甲烷不仅可减少温室气体排放,并且可将其作为能源利用,而填埋场甲烷产量的预测是其利用过程中的首要环节. 笔者介绍并分析了现有几种有关垃圾填埋场甲烷产量预测模型的不足;并从可降解有机组分的厌氧降解机理出发,对降解主要反应方程进行量化,由此推导出产甲烷量化模型. 结果表明:每kg动物、植物、纸类和木竹类垃圾(净垃圾)分别可产生0.578,0.331,0.270和0.319 kg甲烷;在此基础上,推导出有机垃圾填埋过程产甲烷量化预测模型,验证结果显示,该模型预测结果可靠,且结构简单、参数较少、易于量化,由于在计算过程中舍弃了其他不可降解组分的含碳量,因而比现有模型更加精准.      

城市生活垃圾填埋场垃圾-土壤-植物中汞含量的分布特征

在贵阳和武汉市的4座城市生活垃圾填埋场,研究了其中的生活垃圾、土壤和植物中的汞含量分布特征。结果显示,城市生活垃圾的汞含量分布极不均匀,浓度为0.170~46.222 mg.kg-1,几何均值0.574 mg.kg-1,一半以上的样品汞含量低于0.5 mg.kg-1,个别含量异常偏高,可能是被混入的含汞废弃产品污染了,而各个填埋场的垃圾汞含量几何均值相差不大。不同垃圾填埋场覆盖土壤的汞含量差异显著,反映了填埋场所在区域的土壤背景值以及垃圾填埋活动对覆盖土壤的污染程度,有时覆盖土壤的汞含量超过区域土壤背景值的2~23倍。填埋场附近的农田土壤存在一定的汞污染迹象。填埋场生长的植物因生活习性的不同汞含量分布特征也不同,无喙齿冠草为叶>根>茎,狗牙根和硬质早熟禾为地下部分>地上部分。随着填埋场运行时间的增长,附近生长的苔藓汞含量不断升高,封闭填埋场种植的玉米果实有一部分汞含量超过了食用标准,这些都说明填埋场的运行会给周围的生态环境带来一定的汞污染风险。     

苏北某市垃圾填埋场周围地下水氮污染及其形态研究

通过对垃圾填埋场地下水氮污染状况的监测,分析了垃圾填埋场渗滤液的水质特征及其对地下水氮污染的影响。结果表明:垃圾渗滤液含有高浓度的NH4+-N,渗滤液进入土壤后,大量共存离子的竞争吸附减弱了土壤胶体对NH4+-N的吸附能力;土壤中有机质增加后,土壤胶体对NH4+-N的吸附性降低,吸附量减少;且高浓度NH4+-N的存在抑制了硝化作用,从而使大量的NH4+-N未能被土壤胶体吸附转化就随渗滤液继续迁移至地下水中,导致地下水的氮污染主要以NH4+-N为主。     

生物反应器填埋场的发展及应用研究

缩短垃圾稳定化时间,并有效地收集和处理渗滤液及填埋气体,是促使传统卫生填埋法向生物反应器填埋场发展的主要因素。生物反应器填埋场通过回灌渗滤液等控制手段,改善填埋场内部微生化环境,加速填埋场稳定化进程。生物反应器填埋场的关键在于渗滤液收集系统、防渗系统、气体收集系统和渗滤液回灌系统。一些在运行的全规模生物反应器填埋场证明了这种操作方式能加快垃圾降解和填埋气体的产生,减少渗滤液处理量。然而还有一些经济和技术上的不确定性,包括持久有效性、压实度和氧化-还原环境等因素都需要进一步研究。     

Comparison between controlled landfill reactor and conditioned landfill bioreactor

Bioreactor landfills allow a more active landfill management that recognizes the biological, chemical and physical processes involved in a landfill environment. The laboratory-scale simulators of landfill reactors treating municipal solid wastes were studied, the effect of solid waste size, leachate recirculation, nutrient balance, pH value, moisture content and temperature on the rate of municipal solid waste (MSW) biodegradation were determined, and it indicated the optimum pH value, moisture content and temperature decomposing MSW. The results of waste biodegradation were compared with that of the leachate-recirculated landfill simulator and conservative sanitary landfill simulator. In the control experiment the antitheses of a decreasing trend of the organic load, measured as biological oxygen demand and chemical oxygen demand, was shown. An obvious enhancement of effective disposal from conservative sanitary landfill (CSL) simulator, to the leachate-recirculated landfill (LRL) simulator and to the conditioned bioreactor landfill(CBL) simulator would be noted, through displaying the compared results of solid waste settlement, heavy, metal concentration in leachate, methane production rate, biogas composition, BOD and COD as well as their ratio.     

密闭化填埋作业条件下的场内恶臭污染分布情况与分析

随着城市化进程的加剧,填埋场恶臭逐渐成为影响城市生活的重要污染.对于场界范围内的恶臭发生源通常要依靠经验确定,难以对填埋场界范围内的恶臭污染强度分布及变化规律进行科学的描述.利用电子鼻与GPS定位仪对生活垃圾填埋场内的恶臭污染情况进行检测,通过GIS软件作图绘制恶臭污染等强度曲线,对场内强污染源释放点进行确定,发现覆盖膜破损及焚烧火炬尾气排放是造成场内恶臭污染的主要原因.对填埋气产量估算分析表明提高填埋气处理能力是控制恶臭污染的关键.     

户用沼气池建设对改善农村生态环境效果分析

通过对河南省9个县(市)中9个乡(镇)的非沼气户和沼气户土壤、地表径流和室内空气进行监测,定量对比分析了户用沼气池建设对农村生态环境改善效果。结果显示,沼气户土壤中的速效磷、速效钾、有机质和全氮含量要高于非沼气户,且"四位一体"生态模式沼气户土壤中4种养分含量明显高于"三位一体"生态模式;沼气户地表径流中的COD、NH₃-N、 TP浓度均低于非沼气户;沼气户室内空气中的CO、SO₂、NH₃、PM₁₀浓度均低于非沼气户,且室内空气中的4项污染物浓度随季节变化而不同。这说明户用沼气池建设对于增加土壤养分、减轻农村面源污染、改善农户居住环境、实现节能减排效果显著。     

A simulation analysis of the migration and transformation of pollutants contained in landfill leachate

A dynamic composite model for a soil-water system that can be used to simulate the movement of leachate from a landfill. The composite model includes nine sub-models that trace water movement and the migration and transformation of five pollutants(organic N, NE4^- ,NO3^- , NO2^-, and Cl^ - ) in saturated and unsaturated soil. The model to simulate the movement of leachate from a landfill in Laogang Town,Shanghai City was used. In this application, the values for the model parameters were oblained by performing a laboratory simulation experimentof water movement and pollutant migration and transformation in soil columns. Soil and leachate obtained from the landfill site and its vicinitywere used in the laboratory experiments. The model was then used to simulate leachate movement and pollutant activity during the ten-year period when the landfill was in operation and in the twenty-year period following its closure. The simulation results revealed that the leachate migrated into the groundwater at the rate of 90-100 meters per year. This model can be applied in the design of future landfills in China for the purpose of assessing and forecasting leachate plumes.     

Life cycle assessment as a decision support tool for landfill gas-to energy projects

The greenhouse gas (GHG) emissions from MSW landfill, and control methods to eliminate or minimize these impacts including energy recovery from landfill gas (LFG) of MSW landfill in Thailand have been evaluated. Life Cycle Assessment (LCA) is used as the analytical tool to evaluate the environmental consequences of landfilling holistically. The economic implications of the control methods are also briefly assessed. The results show that in terms of GHG emissions as well as in terms of economics, it is more advantageous to have a large centralized landfill and produce electricity from the LFG rather than having several small, localized landfills despite significantly lower transportation requirement for the latter case. Sensitivity analysis revealed that the global warming potential was sensitive to gas collection efficiency as well as methane oxidation rate in the landfill. This study shows the utility of a life cycle approach for evaluating LFG-to-energy (LFGTE) projects.     

生物反应器填埋场临时覆盖材料的选择探讨

生物反应器填埋场要求临时覆盖材料具有较强的渗透能力和一定的均衡回灌渗滤液流动的能力。通过比较,认为生物反应器填埋场在运营前期宜采用粉质砂土、黄土或轻亚粘土作临时覆盖材料,后期采用稳定垃圾分选的细粒物作临时覆盖材料,在雨季时还可配合使用塑料布防止过多的降水进入场内。