生活垃圾可持续化填埋

通过对中国填埋场现状分析,提出了"可持续填理"的概念.认为生活垃圾填埋场将从单纯的最终处置场所演变为填埋与中转相结合的场所.填埋场的可持续发展也将从两方面得到体现:一为垃圾降解过程及其副产品处理中以能量形式得到利用,另一方面为稳定化后的垃圾及填埋场本身空间得到再一次的利用.     

含污泥坑生活垃圾填埋场竖向扩容工程稳定沉降分析

为减少生活垃圾填埋场内污泥坑的存在给填埋场后期竖向扩容工程带来的难度,以辽宁省某含污泥坑生活垃圾填埋场为例,对其竖向扩容工程进行了工艺设计和验证分析.根据工程目标和相关规范,合理确定了扩容后填埋场整体平面布置和填埋堆高等参数,选用原位固化技术对污泥进行了加固处理,并确定了处理后污泥的力学参数设计值.使用Geo-Slop...     

原位回灌对垃圾填埋场稳定化进程影响的实验研究

针对填埋法处理城市生活垃圾造成的土地占用和水资源污染等系列环境问题,通过在实验室搭建的模拟城市生活垃圾填埋场实验台,系统研究了淋滤介质、淋滤量和淋滤频率等条件对生活垃圾填埋场稳定化进程的影响。结果表明:采用垃圾渗滤液原液淋滤、淋滤频率为3次/d、淋滤总量为10L时,垃圾填埋场初期稳定化进程最快;在此条件下,垃圾渗滤液中污染物COD、氨氮和TP出现负增长对应的时间分别为17、29、18d。研究结果对进一步开展垃圾渗滤液深度处理和工程应用等相关研究具有重要的指导意义。     

天子岭垃圾填埋场渗滤液的治理及其工艺改进

对杭州市天子垃圾填埋场采用普通活性污泥法自理垃圾渗滤液的治理效果及及其影响因素与运行费用进行了分析,在此基础上针对渗滤液处理中存在的问题提出了在工艺上加以改进的若干设想。     

垃圾填埋场污泥坑原位修复工程实践

垃圾填埋场内污泥坑的存在严重影响填埋场竖向扩建和填埋堆高。对某垃圾填埋场内污泥坑进行现场勘察取样、原位测试与室内实验,获得污泥的分层及沿深度变化的物理、力学特性,并针对不同分层的污泥,提出表层垃圾清除、污水抽排、泥水混合污泥土工管袋脱水、流塑、软塑污泥原位固化综合处理方法。对污泥坑抽排污水过程中垃圾堆体边坡进行渗流稳定分析,发现渗滤液水位快速下降将导致污泥坑垃圾边坡滑移失稳,在污泥坑治理过程中应采取相应措施。根据污泥坑上覆80~120 m垃圾堆体沿原位固化污泥滑移稳定分析,获得污泥坑原位固化处理强度指标,不排水抗剪强度Cu为40 k Pa。     

垃圾填埋场渗滤液的蒸发处理工艺

垃圾填埋场渗滤液是一种难于处理的废水。本文首先对垃圾渗滤液处理工艺所存在的问题进行分析 ,指出蒸发处理垃圾渗滤液是一类有发展前景的工艺 ,然后综述了垃圾填埋场渗滤液的蒸发处理工艺     

垃圾降解过程中淀粉酶活性测定条件优化

垃圾填埋场中垃圾降解初期,淀粉酶活性对于垃圾填埋场中碳素的转化过程和垃圾填埋场生物学特性的研究有重要意义,而且也可作为垃圾填埋场稳定化机制研究的重要指标之一.以模拟垃圾填埋系统的垃圾为研究对象,通过正交实验(L25(56))对淀粉酶活性的测定条件进行了优化研究.结果表明:(1)正交实验结果表明,对淀粉酶活性测定的影响大...     

原位生物强化好氧稳定化技术在温州市某垃圾填埋场治理工程中的应用

针对目前非正规垃圾填埋场采用的传统原位好氧稳定化技术稳定时间长、效率低的问题,采用原位生物强化好氧稳定化技术,在温州市某非正规垃圾填埋场治理中进行中试应用,并与传统好氧稳定化技术治理效果进行对比试验。研究表明：原位生物强化好氧稳定化技术可加速有机垃圾的生物降解,平均沉降量较好氧稳定化处理高54%;有机质质量分数较好氧稳定化处理低33.8%,提前5个月降低至有机质质量分数的修复目标值16%以下;填埋气体CH4体积分数降低至1.5%左右,较好氧稳定化处理低28.6%,且稳定时间缩短了5个月;渗滤液COD值较好氧稳定化处理低32.8%,BOD值较好氧稳定化处理高47.5%;氨氮质量浓度较好氧稳定化处理低32.7%,原位生物强化好氧稳定化技术的成功运行,为填埋场的快速稳定化提供新的思路与技术手段。     

垃圾填埋场渗滤液的蒸发处理工艺

垃圾填埋场渗滤液是一种难于处理的废水。本文首先对垃圾渗滤液处理工艺所存在的问题进行分析，指出蒸发处理垃圾渗滤液是一类有发展前景的工艺，然后综述了垃圾填埋场渗滤液的蒸发处理工艺。     

城市生活垃圾填埋场渗滤液处理方案探讨

对垃圾填埋场渗滤液水处理工艺方案及相关技术进行了分析 ,针对合并处理与单独处理方案本身存在的问题 ,提出以渗滤液回灌技术作为合并处理中预处理工艺 ,削减单独处理方案中生化负荷并加速渗滤液水质稳定化的设想     

Analysis of long-term settlement of municipal solid waste landfills as determined by various settlement estimation methods

In this study, several existing municipal solid waste (MSW) settlement estimation methods are reviewed and applied to analyze the settlement data of nine MSW landfills. Because a biodegradation-related settlement contributes differently to a long-term total settlement depending on the age of landfills, the actual MSW landfill sites are classified into three groups to specifically address the validity of each method in its prediction of a long-term settlement for each age category. Results demonstrate that there are considerable decreases in predicted settlement potentials as fill age increases. Comparisons indicate that the individual estimation methods display a considerable variation in predicting settlements in the fresh MSW landfills. On the other hand, for the old refuse landfills, all of the estimation methods, except the extended soil model, predict low settlement potentials.     

Compressibility of municipal solid waste codisposed with fly ash

If a municipal solid waste (MSW) landfill is used as the foundation for a construction site, the change in the loading conditions may cause considerable compression of the landfill. Therefore, reinforcement to compensate for the loose compression nature of a MSW landfill is a very important design factor for geotechnical engineers when considering the end-use of the landfill. In this study, we discuss a possible technique for stabilizing MSW landfills through the codisposal of municipal solid waste and fly ash. To estimate the stabilization based on the compression characteristics of the codisposed landfill, we performed tests using a large compression set and experimental cells. According to the test results, if the proportion of fly ash is increased, initial and long-term compression could be reduced.     

Analysis of Long-Term Settlement of Municipal Solid Waste Landfills as Determined by Various Settlement Estimation Methods

Abstract

In this study, several existing municipal solid waste (MSW) settlement estimation methods are reviewed and applied to analyze the settlement data of nine MSW land-fills. Because a biodegradation-related settlement contributes differently to a long-term total settlement depending on the age of landfills, the actual MSW landfill sites are classified into three groups to specifically address the validity of each method in its prediction of a long-term settlement for each age category. Results demonstrate that there are considerable decreases in predicted settlement potentials as fill age increases. Comparisons indicate that the individual estimation methods display a considerable variation in predicting settlements in the fresh MSW landfills. On the other hand, for the old refuse landfills, all of the estimation methods, except the extended soil model, predict low settlement potentials.     

Permeability test and slope stability analysis of municipal solid waste in Jiangcungou Landfill,Shaanxi, China

With the rapid increase of city waste, landfills have become a major method to deals with municipal solid waste. Thus, the safety of landfills has become a valuable research topic. In this paper, Jiangcungou Landfill, located in Shaanxi, China, was investigated and its slope stability was analyzed. Laboratory tests were used to obtain permeability coefficients of municipal solid waste. Based on the results, the distribution of leachate and stability in the landfill was computed and analyzed. These results showed: the range of permeability coefficient was from 1.0 × 10^–7 cm sec^–1 to 6.0 × 10^–3 cm sec^–1 on basis of laboratory test and some parameters of similar landfills. Owing to the existence of intermediate cover layers in the landfill, the perched water level appeared in the landfill with heavy rain. Moreover, the waste was filled with leachate in the top layer, and the range of leachate level was from 2 m to 5 m in depth under the waste surface in other layers. The closer it gets to the surface of landfill, the higher the perched water level of leachate. It is indicated that the minimum safety factors were 1.516 and 0.958 for winter and summer, respectively. Additionally, the slope failure may occur in summer.

Implications: The research of seepage and stability in landfills may provide a less costly way to reduce accidents. Landslides often occur in the Jiangcungou Landfill because of the high leachate level. Some measures should be implemented to reduce the leachate level. This paper investigated seepage and slope stability of landfills by numerical methods. These results may provide the basis for increasing stability of landfills.     

A survey of municipal solid waste landfills in Beijing during 2009–2011

The investigation of municipal solid waste (MSW) treatment in China is rare due to its sensitivity and difficulty in terms of access. We chose Beijing, the capital of China, as an example to identify the characteristics of MSW landfill treatments using a 2-month investigation with 20 participants. MSW landfill treatments account for nearly 70% of the annual MSW disposal in Beijing; the landfill processes are equipped with many kinds of technologies and consume a large amount of energy and produce a variety of contaminants. The cover method (the most obvious difference in landfill tamping) mainly includes high-density polyethylene (HDPE) geomembranes with loess and soil alone (i.e., loess or sandy soil). We investigated the actual conditions of landfills and collected data on leachate and landfill gas (LFG) emissions and energy consumption during 2009–2011. The results indicated that the cover method employed by landfills was related to treatment quantity, operation, and especially landfill location. Early large-scale landfills located in plains were covered with HDPE geomembranes, and newly built landfills covered with soil tended to be equipped with HDPE covers. Using HDPE cover also contributed greatly to LFG production due to its impermeability but had no remarkable effect on leachate yield reduction due to the dry climate in Beijing. The potential was reinforced by the potentials of decrement and reuse. The disposal method of LFG can be optimized, and the power generated by the LFG process can meet the landfill demand. The gray water recycled from the leachate could be used in the landfill process.

     

垃圾填埋气收集控制的CFD数值模拟应用研究

基于多孔介质渗流理论,给出了填埋气在填埋场内流动控制方程组及其定解条件,但实际填埋场的不规则边界使其很难求得解析解。建立填埋场竖井抽气物理模型,采用计算流体力学数值模拟软件PHONEICS求得控制方程的数值解,并用相关文献的结论进行校验,结果与前人结论相吻合。将该方法应用于实际填埋场抽气系统的设计,通过PHONEICS软件编程接口二次开发计算负压抽气条件下流入抽气系统的外部空气量,由此引入抽气效率做为抽气效果的评价指标,模拟了传统等边三角形布置竖井抽气系统的运行效果,并根据模拟结果对传统竖井抽气系统进行优化。     

Polymers as Solid Waste in Municipal Landfills

Abstract

Synthetic polymers reach municipal landfills as components of products such as waste household paints, packaging films, storage containers, carpet fibers, and absorbent sanitary products. Some polymers in consumer products that reach landfills are designed to photodegrade or biodegrade. This article examines the significance of degradable polymers in management of solid waste in municipal landfills. Most landfills are not designed to photodegrade or biodegrade solid waste. Landfill disposal of stable polymers such as polyacrylics and polyethylenes is not associated with significant polymer degradation or mobility. Stability to photodegradation and biodegradation is an advantage when municipal landfills are used for disposal of polymer products as solid waste. Use of landfill disposal can be a responsible means to manage polymer waste and can be part of an overall waste management plan which includes source reduction, recycling, reuse, composting, and waste-to-energy incineration.     

Non-controlled biogenic emissions to the atmosphere from Lazareto landfill, Tenerife, Canary Islands

GOAL, SCOPE AND BACKGROUND: [corrected] Historically, landfills have been the simplest form of eliminating urban solid waste with the minimum cost. They have been the most usual method for discarding solid waste. However, landfills are considered authentic biochemical reactors that introduce large amounts of contaminants into the environment in the form of gas and leachates. The dynamics of generation and the movement of gas in landfills depend on the input and output parameters, as well as on the structure of the landfill and the kind of waste. The input parameters include water introduced through natural or artificial processes, the characteristics of the urban solid waste, and the input of atmospheric air. The main output parameters for these biochemical reactors include the gases and the leachates that are potentially pollutants for the environment. Control systems are designed and installed to minimize the impact on the environment. However, these systems are not perfect and a significant amount of landfill gas could be released to the atmosphere through the surface in a diffuse form, also known as Non-controlled emission. In this paper, the results of the Non-controlled biogenic gas emissions from the Lazareto landfill in Tenerife, Canary Islands, are presented. The purpose of this study was to evaluate the concentration of CH4 and CO2 in the soil gas of the landfill cover, the CH4 and CO2 efflux from the surface of the landfill and, finally, to compare these parameters with other similar landfills. In this way, a better understanding of the process that controls biogenic gas emissions in landfills is expected. METHODS: A Non-controlled biogenic gas emission survey of 281 sampling sites was carried out during February and March, 2002. The sampling sites were selected in order to obtain a well-distributed sampling grid. Surface landfill CO2 efflux measurements were carried out at each sampling site on the surface landfill together with soil gas collection and ground temperatures at a depth of 30-40 cm.The CH4 efflux was computed from CO2 efflux and from the ratio CH4/CO2 in the soil gas. Soil gas samples were collected at a depth of 30-40 cm using a metallic probe and 20 cc hypodermic syringes, and later stored in evacuated 10 cc vacutainers for laboratory analysis of bulk composition. The gas sample was introduced in a vacutainer filled with deionized water and displacing the water until the vacutainer was filled with the gas sample in order to avoid air contamination from entering. The surface landfill temperature of the landfill was measured at a depth of 40 cm using a digital thermometer type OMEGA 871A. Landfill gases, CO2 and CH4, were analyzed within 24 hours using a double channel VARIAN micro-GC QUAD CP-2002P, with a 10 meter PORAPLOT-Q column, a TCD detector, and He as a carrier gas. The analysis temperature was 40 degrees C and the injection time was 10 msec. Surface landfill CO2 efflux measurements were performed using a portable NDIR spectrophotometer Licor-800 according to the accumulation chamber method (Chiodini et al. 1996). The data treatment, aimed at drawing the flux map and computing the total gas output, was based on the application of stochastic simulation algorithms provided by the GSLIB program (Deutsch and Journel 1998). RESULTS: Diffuse CH4 and CO2 efflux values range from negligible values up to 7,148 and 30,573 g m(-2) d(-1), respectively. The spatial distribution of the concentration and efflux of CO2, CH4 and soil temperature, show three areas of maximum activity in the landfill, suggesting a non-uniform pattern of diffuse degassing. This correlation between high emissions and concentration of CO2, CH4 and soil temperatures suggests that the areas of higher microbial activity and exothermic reactions are releasing CO2 and CH4 to the atmosphere from the landfill. Taking into consideration the spatial distribution of the CO2 and CH4 efflux values as well as the extension of the landfill, the Non-controlled emission of CO2 and CH4 to the atmosphere by the Lazareto's landfill are of 167 +/- 13.3 and 16 +/- 2.5 t d(-1), respectively. DISCUSSION: The patterns of gas flow within the landfill seem to be affected by boundary materials at the sides. The basalt layers have a low permeability and the gas flow in these areas is extensive. In this area, where a basalt layer does not exist, the flow gas diffuses toward the sea and the flux emissions at the landfill surface are lower. This behavior reflects the possible dissolution of gases into water and the deflection of gases towards the surface at the basalt boundary. The proximity to the sea, the installation of a palm tree garden and, as a result, the contribution of water coming from the watering of this garden has reactivated the system. The introduction of sea water into the landfill and the type of boundary could be defining the superficial gas discharges. CONCLUSIONS: Results from this study indicate that the spatial distribution of Non-controlled emission of CO2 and CH4 at the Lazareto's landfill shows a non-uniform pattern of diffuse degassing. The northeast, central and northwest areas of the Lazareto's landfill are the three areas of high emissions and concentration of CO2 and CH4, and high temperatures. The correlation between high emissions and the concentration of CO2, CH4, and the high temperatures suggest that the areas of higher microbial activity and exothermic reactions are releasing more CO2 and CH4 to the atmosphere from the landfill. A high concentration of CO2 is probably due to the presence of methanotrophic bacteria in the soil atmosphere of the landfill. Patterns of gas flow within the landfill seem to be affected by boundary materials (basalt layers) of low permeability, and side boundaries of the flux emissions at the surface are higher. At the sides of seawater and sediment boundaries, flux emissions at the landfill surface are lower. This behavior reflects a possible dissolution of gases into the water and the deflection of gases towards the surface at the basalt boundary. With this study, we can compare the data obtained in this landfill with other landfills and observe the different levels of emission. The proximity to the sea and the installation of the palm tree garden palms and, as a result, the contribution of water coming from the watering of this garden has reactivated the system. Many landfills worldwide located in similar settings could experience similar gas production processes. RECOMMENDATIONS AND PERSPECTIVES: The need for investigating and monitoring sea water and sediment quality in these landfills is advisable. Concentrations and fluxes of contaminants and their impact in the area should be assessed. With this study we can compare the data obtained in these landfills with other landfills and observe the different levels of emission.     

Monitoring leachate composition at a municipal landfill site in New Delhi, India

Most of the landfills in developing countries do not have any liner at the base, or a drainage layer or a proper top cover, which results in the potential problem of groundwater/surface water contamination due to the leachate. Hence, to decide whether the leachate is to be collected and treated, or may be allowed to discharge into the adjoining soil or public sewer or surface waterbody, it is essential to have an estimate of the amount of leachate and, more importantly, the composition and strength of the leachate and variation of leachate contaminants with time as the landfill site develops. In this paper, the experimental work carried out at one of the landfills in New Delhi, India, to ascertain the composition of leachate, and its effect on the groundwater in the existing situation is presented. The variation in the leachate composition with the age of deposition of solid waste has been studied. The study indicates that the leachate composition varies considerably with the age of deposition of the waste. It may be worthwhile to use different methods for the treatment of leachate from different parts of the landfill, if collected separately. It has also been concluded that since leachate contains high concentrations of organic and inorganic constituents, including heavy metals, liners must be used at the landfills. The presence of bore wells at landfill sites to draw groundwater threatens to contaminate the groundwater, and immediate remediation steps should be taken at all landfill sites that have groundwater bore wells.     

Feasibility of biochar application on a landfill final cover—a review on balancing ecology and shallow slope stability

Due to the increasing concerns on global warming, scarce land for agriculture, and contamination impacts on human health, biochar application is being considered as one of the possible measures for carbon sequestration, promoting higher crop yield and contamination remediation. Significant amount of researches focusing on these three aspects have been conducted during recent years. Biochar as a soil amendment is effective in promoting plant performance and sustainability, by enhancing nutrient bioavailability, contaminants immobilization, and microbial activities. The features of biochar in changing soil physical and biochemical properties are essential in affecting the sustainability of an ecosystem. Most studies showed positive results and considered biochar application as an effective and promising measure for above-mentioned interests. Bio-engineered man-made filled slope and landfill slope increasingly draw the attention of geologists and geotechnical engineers. With increasing number of filled slopes, sustainability, low maintenance, and stability are the major concerns. Biochar as a soil amendment changes the key factors and parameters in ecology (plant development, soil microbial community, nutrient/contaminant cycling, etc.) and slope engineering (soil weight, internal friction angle and cohesion, etc.). This paper reviews the studies on the production, physical and biochemical properties of biochar and suggests the potential areas requiring study in balancing ecology and man-made filled slope and landfill cover engineering. Biochar-amended soil should be considered as a new type of soil in terms of soil mechanics. Biochar performance depends on soil and biochar type which imposes challenges to generalize the research outcomes. Aging process and ecotoxicity studies of biochar are strongly required.