周口北郊垃圾填埋场渗滤液的渗漏量及COD变化模拟分析

周口北郊垃圾填埋场为非卫生填埋,已对周围地下水环境造成了污染。在建立污染物溶出模式的基础上,分析了该非卫生填埋场垃圾渗滤液中化学需氧量(COD)的变化规律,用WHI UnSat Suite软件HELP模块估计了停止填埋后的现状和采用地表防渗措施情况下渗滤液的渗漏量。结果表明,周口北郊垃圾在10a垃圾填埋过程中每年有1 000～5 000m3渗滤液进入含水层,其COD质量浓度大致为2 000mg/L。停止垃圾堆放后,在没有覆盖措施条件下,渗滤液渗漏量平均值为2 500m3/a。在垃圾表层铺设防渗措施可有效减少99%的渗漏量,但仍有12m3/a渗滤液渗漏进入含水层。     

非卫生垃圾填埋场渗滤液污染防治对策研究

针对非卫生垃圾填埋场环境污染问题,以某垃圾填埋场为例,通过 WHI UnSat Suite软件 HELP模块计算不同填埋条件下渗滤液渗漏量。利用GMS模拟了该垃圾场中心抽水条件下污染物迁移变化规律。结果表明,简单地表防渗条件下,渗滤液渗漏量为现状条件下的50%,增铺 HDPE土工膜后,渗漏量可减少99%。卫生填埋渗滤液仅为现状条件下的3.6＆#215;10-3倍。当抽水量为2000 m3/d时,Cl-浓度呈明显下降趋势,由84 mg/L降至80.1 mg/L。     

上海某生活垃圾填埋场对浅层地下水水质的影响

垃圾填埋是目前处理城市生活垃圾普遍使用的方式,由此产生的垃圾渗滤液成为主要的地下水污染源.本文以上海市某生活垃圾填埋场作为研究对象,研究垃圾填埋对地下水的影响.通过监测该场地垃圾填埋前后2年内场区及周边地下水水质的变化情况,以垃圾填埋前调查区的地下水样品分析结果为本底值,采用本底法对地下水水质进行评价来判定地下水是否受到垃圾渗滤液的影响.评价结果显示,对于本研究的水质动态监测阶段,调查区内的浅层地下水水质暂未受到垃圾渗滤液的影响,个别监测井水质发生较大变化是由于填埋场施工建设过程中,破坏了监测井井盖及挖穿了井边含水层顶层.随着整个垃圾填埋场运行时间的延长,防渗漏措施的有效性以及垃圾渗滤液对周边地下水的影响还需要进一步研究.     

天然与改性膨润土组合处理难生物降解垃圾渗滤液的实验研究

以北京市阿苏卫垃圾填埋场中晚期渗滤液为研究对象,通过正交实验的方法分析了改性土、原土、明矾、改性土加明矾等的用量及搅拌速度、搅拌时间、静置时间等因素对垃圾渗滤液CODcr去除率的影响。通过对改性土、原土、明矾处理垃圾渗滤液的机理进行分析后,将改性土、原土分别用来处理垃圾渗滤液中可溶性物质中的疏水性物质和亲水性物质,并结合明矾的絮凝作用组合处理垃圾渗滤液。处理后垃圾渗滤液CODcr值从4700mg/L明显下降到839mg/L,CODcr去除率为82.15%,BOD5从700mg/L下降到263mg/L,BOD5去除率为62.43%。有机改性膨润土、明矾、原土组合处理是一种有效的处理垃圾渗滤液方法。     

垃圾渗滤液在含水层中的污染规律研究——以阜新市垃圾填埋场为例

垃圾的堆存和填埋会产生大量的渗滤液。渗滤液对垃圾填埋场周围环境能够造成严重污染,尤其使地下水质污染而丧失利用价值。通过阜新市垃圾填埋场现场采集新鲜渗滤液水样、垃圾堆体附近土样的实验研究,获得了新鲜渗滤液的各组分浓度和垃圾堆体附近土壤的性质。结合当地地理气候等情况揭示了垃圾渗滤液中污染溶质在地下水系统中的迁移转化的动态过程,定量化预测了污染范围及时空分布,为研究该地区地下水污染控制、管理和评价提供了可靠依据。     

不同龄期垃圾渗滤液对浅层地下水污染的实验研究

为了深入了解垃圾渗滤液对浅层地下水污染的机理,揭示不同龄期垃圾渗滤液在浅层地下水中多组分运移规律,文章以阜新市垃圾填埋场为研究对象,通过室内土柱对比实验,研究了不同龄期垃圾渗滤液在浅层地下水中多组分运移的机理和规律。结果表明不同龄期垃圾渗滤液在入渗过程中都会引起地下水不同程度的污染,且新鲜垃圾渗滤液较老龄垃圾渗滤液更易污染地下水,其污染机理主要为吸附、解析、溶解、沉淀和离子交换等水岩作用。研究结果为今后垃圾填埋场的治理和地下水的修复提供理论依据。     

高效厌氧+A/O+MBR+NF多级组合工艺处理某垃圾填埋场垃圾渗滤液

本项目采用厌氧+A/O+MBR+NF多级组合工艺处理某垃圾填埋场垃圾渗滤液,设计处理规模为300m3/d,出水水质可达到《生活垃圾填埋场污染控制标准》(GB16889-2008)中一般地区对渗滤液出水水质的要求。     

垃圾填埋场对周边地质环境影响与防治对策

垃圾填埋场对周边地质环境的污染越来越受到研究人员的重视,其影响因素复杂,不仅与MSW的性质有关,还与垃圾填埋场的类型及其所处地质环境有密切关系。为分析垃圾填埋场中的渗滤液、重金属以及其他有害物质对周边地质环境(地下水环境、土壤环境)的影响规律,对大量相关文献和实验资料进行研究分析。研究结果表明:渗滤液是垃圾填埋场影响周围地质环境最为重要的因素,对渗滤液污染地表水及地下水情况和防治方法进行了探讨;同样渗滤液也是重金属污染土壤的载体,重金属在土壤剖面中的滞留量一般随深度的增加而逐渐减少;重金属对土壤的污染具有积累性和滞后性特点,随着填埋时间的延长污染加重。最后,根据其污染途径和污染规律,提出了相应具体防治对策。     

矿物法组合处理垃圾填埋场渗滤液的研究

垃圾填埋场渗滤液水质复杂,危害性大,对其无害化处理尚未得到很好解决。研究发现,垃圾渗滤液中有机污染物可标识划分为亲水性和疏水性两大类物质。实验针对性采用亲水的天然膨润土处理亲水性有机物,疏水的有机膨润土处理疏水性有机物,再结合鸟粪石结晶法去除氨氮,从而获得一套处理中晚期垃圾渗滤液的经济高效的矿物法组合处理技术。采用GC-MS技术鉴定经矿物法处理后的垃圾渗滤液,亲水性和疏水性有机污染物的种类和含量都明显降低。检测进水与出水的COD、氨氮及重金属浓度这三项关键指标,垃圾渗滤液原液COD为2566 mg/L,氨氮3859 mg/L,重金属Hg为0.305 mg/L。矿物法组合处理后出水的COD为245mg/L,氨氮48 mg/L,重金属Hg未检出。矿物组合法为垃圾渗滤液的无害化处理提供了一条新的思路。     

阜新城市垃圾填埋场对地下水污染的研究

随着我国城市化的发展,城市生活垃圾产量剧增,垃圾渗滤液对地下水的污染问题已成为当前主要的水环境污染问题。通过对阜新市城市垃圾填埋场地理、地质和气候特征的调查,结合阜新市城市发展现状,分析了阜新市城市垃圾填埋场垃圾成分,渗滤液产生量及渗滤液中污染物的浓度,得出了阜新市城市垃圾填埋场渗滤液中各种污染物污染地下水的源强度。采用数值模拟的方法,对垃圾渗滤液污染地下水的情况进行模拟分析,验证了模拟方法的正确性,并对今后的污染情况进行了预测分析。     

Geochemical assessment of groundwater quality in vicinity of Bhalswa landfill,Delhi, India,using graphical and multivariate statistical methods

A geochemical assessment of groundwater quality and possible contamination in the vicinity of the Bhalswa landfill site was carried out by using a hydrochemical approach with graphical and multivariate statistical methods with the objective of identifying the occurrence of various geochemical processes and understanding the impact of landfill leachates on groundwater quality. Results indicate that nitrate, fluoride and heavy-metal pollution are in an alarming state with respect to the use of groundwater for drinking purposes. Various graphical plots and statistical analyses have been applied to the chemical data based on the ionic constituents, water types, and hydrochemical facies to infer the impact of the landfill on groundwater quality. The statistical analysis and spatial and temporal variations indicate the leaching of contaminants from the landfill to the groundwater aquifer system. The concentrations of heavy metals in the landfill leachates are as follows: Fe (22 mg/l), Mn (~20 mg/l), Cu (~10 mg/l), Pb (~2 mg/l), Ni (0.25 mg/l), Zn (~10 mg/l), Cd (~0.2 mg/l), Cl⁻ (~4,000 mg/l), SO₄²⁻ (~3,320 mg/l), PO₄³⁻ (~4 mg/l), NO₃⁻ (30 mg/l) and fluoride (~50 mg/l); all were much higher than the standards. The study reveals that the landfill is in a depleted phase and is affecting groundwater quality in its vicinity and the surrounding area due to leaching of contaminants.     

Permeability of Municipal Solid Waste in Bioreactor Landfill with Degradation

Bioreactor landfills are operated for rapid stabilization of waste, increased landfill gas generation for cost-effective energy recovery, gain in landfill space, enhanced leachate treatment, and reduced post closure maintenance period. The fundamental process of waste stabilization in bioreactor landfill is recirculation of generated leachate back into the landfills. This creates a favorable environment for rapid microbial decomposition of the biodegradable solid waste. In order to better estimate the generated leachate and design of leachate recirculation system, clear understanding of the permeability of the Municipal Solid Waste (MSW) with degradation and the factors influencing the permeability is necessary. The objective of the paper is to determine the changes in hydraulic properties of MSW in bioreactor landfill with time and decomposition. Four small-scale bioreactor landfills were built in laboratory and samples were prepared to represent each phase of decomposition. Then, the changes in hydraulic properties of MSW in bioreactor landfill with time and decomposition were determined. A series of constant head permeability tests were performed on the samples generated in laboratory scale bioreactor landfills to determine variation of permeability of MSW with degradation. The test results indicated that the permeability of MSW in bioreactor landfills decreases with decomposition. Based on the test results, the permeability of MSW at the first phase of degradation was estimated as 0.0088 cm/s at density 700 kg/m³. However, with degradation, permeability decreased to 0.0013 cm/s at the same density, for MSW at Phase IV.     

Deterioration of groundwater quality in the vicinity of an active open-tipping site in West Malaysia

There is an urgent need for characterization of leachate arising from waste disposal to ensure a corresponding effective leachate management policy. Field and laboratory studies have been carried out to investigate the impact of municipal landfill leachate on the underlying groundwater at a site in West Malaysia. The solid waste was disposed of directly onto an unprotected natural soil formation. This situation was made worse by the shallow water table. The hydrochemical composition of groundwater in the vicinity of the site (background) is a dilute mixed cation, bicarbonate water. The high ionic balance error of ~13.5% reveals that the groundwater body underneath the site was a highly contaminated leachate rather than contaminated groundwater. Elevated concentration of chloride (355.48 mg/L), nitrate (10.40 mg/L as NO₃), nitrite (14.59 mg/L), ammoniacal-N (11.61 mg/L), sodium (227.56 mg/L), iron (0.97 mg/L), and lead (0.32 mg/L) measured downgradient indicate that the contamination plume has migrated further away from the site. In most cases, the concentration of these contamination indicators, together with the ranges of sodium percentage (66.3–89.9%) and sodium adsorption ratio (10.1–19.7%), were found to be considerably higher than the limit values of safe water for both domestic and irrigation purposes, respectively.     

Impacts of Human Activities on Groundwater Quality of an Alluvial Aquifer: A Case Study of the Eskişehir Plain, Turkey

Hydrochemical and water-quality (except biological) data obtained through a two-year sampling and analysis program indicate that the highest concentrations of groundwater pollution occur in the central and eastern parts of Eski?ehir city. Groundwater quality degradation outside the urban area results from agricultural activities. The most serious pollution of groundwater in the Eski?ehir plain is from nitrogen compounds (ammonia, nitrite, and nitrate). The concentrations of ammonia, nitrite, and nitrate of the 51 surveyed water wells range from 0.01–1.65 mg/L, 0.01–1.80 mg/L, and 1.1–257.0 mg/L, respectively. Orthophosphate concentrations in groundwater range from 0.01–1.25 mg/L. Considerable seasonal fluctuation in the groundwater quality was observed. In general, the groundwater quality in wet seasons was better than the quality in dry seasons.     

The Role of Fracture Structure in Leachate Pollution at Landfills： A Case Study of a Landfill in Chongqing City

This paper studies a landfill where there are three faults running through.As serious pollution has occurred to the geological environment,the landfill is to be closed up and renovated.The paper aims to explore the role of fracture structure in leachate pollution at the landfill.The research was carried out in several stages.First,mathematical models of the pre-renovation landfill with three faults running through and the landfill after renovation were established.And then,the boundary conditions and parameters of the two mathematical models were determined.The groundwater level of the landfills was simulated in order to modify the two mathematical models.As a result,a feasible mathematical model was achieved.Based on this model,a comparison was made of the COD concentration variations in the inside leachate and outside leachate between the two landfills. Accordingly,the impacts of the fracture structure on the pollution of leachate at the landfills could be identified.The study results show that while faults contribute to the migration of leachate,they also serve as a confluence of leachate,thus further deteriorating the environment.The COD concentrations of the inside leachate and the outside leacbate of the pre-renovation landfill are respectively 800 mg/L and 220 mg/L higher than those of the post.renovation landfill.Therefore,measures must be taken to handle the leachate seepage in areas where there are faults as well as the neighboring areas so as to get the environmental pollution under control.     

The Role of Fracture Structure in Leachate Pollution at Landfills: A Case Study of a Landfill in Chongqing City

This paper studies a landfill where there are three faults running through. As serious pollution has occurred to the geological environment, the landfill is to be closed up and renovated. The paper aims to explore the role of fracture structure in leachate pollution at the landfill. The research was carried out in several stages. First, mathematical models of the pre-renovation landfill with three faults running through and the landfill after renovation were established. And then, the boundary conditions and parameters of the two mathematical models were determined. The groundwater level of the landfills was simulated in order to modify the two mathematical models. As a result, a feasible mathematical model was achieved. Based on this model, a comparison was made of the COD concentration variations in the inside leachate and outside leachate between the two landfills. Accordingly, the impacts of the fracture structure on the pollution of leachate at the landfills could be identified. The study results show that while faults contribute to the migration of ieachate, they also serve as a confluence of leachate, thus further deteriorating the environment. The COD concentrations of the inside leachate and the outside leachate of the pre-renovation landfill are respectively 800 mg/L and 220 mg/L higher than those of the post-renovation landfill. Therefore, measures must be taken to handle the ieachate seepage in areas where there are faults as well as the neighboring areas so as to get the environmental pollution under control.     

Assessment of the physicochemical parameters and heavy metals toxicity of leachates from municipal solid waste open dumpsite

Heavy metals and physicochemical characteristics of the different sites of the municipal solid waste dumpsite at Olusosun Landfill, Lagos, Nigeria, were investigated. The dormant site of the landfill has the potential of being a source of immediate environmental risk compared to the active and abandoned site, with the active site exhibiting tendency to be a likely source of Pb, Cd and Zn pollution. Zn was the most abundant metal in the area (0.264–0.947 mg/L) while Cd concentration was the lowest (0.001–0.022 mg/L). Pb, Cd, Zn were from anthropogenic sources and correlated significantly with chemical oxygen demand and oil and grease. Cu and Cr were more abundant in the dormant site and are attached to the solids as indicated by their significant correlation with TS and SS. The physicochemical characteristic of the leachate from the landfill indicate that they were more alkaline in nature, with TA range of 2354 to 7946 mg/L while the chemical oxygen demand values was also high 518.14 to 725.01 mg/L. The comparative analysis of the dormant site with other dormant site reveal a moderate concentration of the parameters measured but could contaminate the neighboring groundwater if not checked.     

Environmental impact of an urban landfill on a coastal aquifer (El Jadida, Morocco)

The El Jadida landfill is one among many uncontrolled dumping sites in Morocco with no bottom liner. About 150 tons/day of solid wastes from mixed urban and industrial origins are placed directly on the ground. At the site of this landfill, the groundwaters circulate deeply (10–15 m) in the Cenomanian rock (calcareous–marl), which is characterised by an important permeability from cracks. The soil is sand–clay characterized by a weak coefficient of retention.The phreatic water ascends to the bottom of three quarries, which are located within the landfill. These circumstances, along with the lack of a leachate collection system, worsen the risks for a potential deterioration of the aquifer.To evaluate groundwater pollution due to this urban landfill, piezometric level and geochemical analyses have been monitored since 1999 on 60 wells. The landfill leachate has been collected from the three quarries that are located within the landfill. The average results of geochemical analyses show an important polluant charge vehiculed by landfill leachate (chloride = 5680 mg l⁻¹, chemical oxygen demand = 1000 mg l⁻¹, iron = 23 000 μg l⁻¹). They show also an important qualitative degradation of the groundwater, especially in the parts situated in the down gradient area and in direct proximity to the landfill. In these polluted zones, we have observed the following values: higher than 4.5 mS cm⁻¹ in electric conductivity, 1620 and 1000 mg l⁻¹ respectively in chlorides and sulfate (), 15–25 μg l⁻¹ in cadmium, and 60–100 μg l⁻¹ in chromium. These concentrations widely exceed the standard values for potable water.Several determining factors in the evolution of groundwater contamination have been highlighted, such as (1) depth of the water table, (2) permeability of soil and unsaturated zone, (3) effective infiltration, (4) humidity and (5) absence of a system for leachate drainage. So, to reduce the pollution risks of the groundwater, it is necessary to set a system of collection, drainage and treatment of landfill leachates and to emplace an impermeable surface at the site of landfill, in order to limit the infiltration of leachate.     

电化学循环井驱动模拟含水层化学氧化降解三氯乙烯

传统原位化学氧化地下水修复技术存在氧化剂迁移距离短和利用率低等问题。本研究在双井循环模式促进传质的基础上,通过注水井中的地下水电解原位提供O₂和H₂,配合乙二胺四乙酸(ethylenediamine tetraacetic acid,EDTA)络合溶解出含水层Fe(Ⅱ),活化O₂产生羟基自由基(•OH),实现地下水三氯乙烯(TCE)的氧化降解。在填充了砂土和黏土互层的二维砂槽中,设置电流为0.2 A、流速为72 cm/d、初始TCE浓度为3 mg/L,经过9 d的连续通电处理后,TCE浓度降低到1 mg/L,降解率达到67%。通电前投加0.5 mmol/L EDTA,经过1 d水流循环后含水层中溶解态Fe(Ⅱ)浓度从02 mg/L增加到414 mg/L,黏土区域较高。通电过程中,循环井促进O₂、Fe(Ⅱ)-EDTA和TCE的有效接触与反应,使TCE氧化降解。通电初期,黏土区域Fe(Ⅱ)氧化速率、TCE降解速率较周围慢,后期差异逐渐减小。未通电时加入醋酸钠可促进Fe(Ⅲ)还原,使含水层中铁循环利用。该修复过程通过循环井提升了氧化剂迁移距离,使用源于含水层的Fe(Ⅱ)-EDTA和稳定性较好的O₂提高了氧化剂利用率,有望应用于有机污染地下水修复。