垃圾填埋场渗滤液水量平衡的实验研究

通过回灌条件下的水量平衡实验,分析了回灌条件下水分运动各个要素(降水、径流、下渗、蒸发)之间的关系。在回灌条件下,土壤蒸发能满足渗滤液的水量平衡,下渗水量通过土壤蒸发作用得以大量削减。土壤水分饱和程度对蒸发量的影响是明显的,土壤水分供给充足时,土壤蒸发按蒸发能力进行,蒸发量大而稳定。     

苏州七子山垃圾填埋场渗沥液设计水质的估算

在对垃圾填埋场渗沥液污染物的转化、溶出规律分析的基础上，建立了污染物溶出模式和污染物负荷计算模式，并结合苏州七子山垃圾填埋场的实际情况，确定了其渗沥液在不同条件下的水质。研究表明，在填埋场填埋稳定期的枯水期和丰水期的ＣＯＤｃｒ和ＢＯＤ５浓度分别为２７．２４～４０．８６ｍｇ／ｌ、１３．１７～１９．７５ｍｇ／ｌ和１３．４６～２０．２１ｍｇ／ｌ、６．５１～９．７７ｇ／ｌ；在填埋场封场后枯水期和丰水期的ＣＯＤｃｒ和ＢＯＤ５分别为４．８８～７．３３ｇ／１、２．３６～３．５４ｇ／ｌ和２．２２～３．３４ｇ／ｌ、１．０８～１．６１７ｇ／ｌ。     

Monitoring of Gin Drinkers' Bay landfill,Hong Kong: I. Landfill gas on top of the landfill

The present study centered on the composition of landfill gas and its effects on soil and plants at the Gin Drinkers' Bay (GDB) landfill in Hong Kong This first part of the study was a whole-year monitoring of landfill gas composition in the gas ventilation system installed on top of the landfill Methane, carbon dioxide, oxygen, and ethylene were measured It was shown that gas generation was positively correlated with the amount of precipitation and air temperature and negatively correlated with atmospheric pressure     

Biogeochemical processes at the fringe of a landfill leachate pollution plume: potential for dissolved organic carbon, Fe(II), Mn(II), NH4, and CH4 oxidation

Various redox reactions may occur at the fringe of a landfill leachate plume, involving oxidation of dissolved organic carbon (DOC), CH4, Fe(II), Mn(II), and NH4 from leachate and reduction of O2, NO3 and SO4 from pristine groundwater. Knowledge on the relevance of these processes is essential for the simulation and evaluation of natural attenuation (NA) of pollution plumes. The occurrence of such biogeochemical processes was investigated at the top fringe of a landfill leachate plume (Banisveld, the Netherlands). Hydrochemical depth profiles of the top fringe were captured via installation of a series of multi-level samplers at 18, 39 and 58 m downstream from the landfill. Ten-centimeter vertical resolution was necessary to study NA within a fringe as thin as 0.5 m. Bromide appeared an equally well-conservative tracer as chloride to calculate dilution of landfill leachate, and its ratio to chloride was high compared to other possible sources of salt in groundwater. The plume fringe rose steadily from a depth of around 5 m towards the surface with a few meters in the period 1998-2003. The plume uplift may be caused by enhanced exfiltration to a brook downstream from the landfill, due to increased precipitation over this period and an artificial lowering of the water level of the brook. This rise invoked cation exchange including proton buffering, and triggered degassing of methane. The hydrochemical depth profile was simulated in a 1D vertical reactive transport model using PHREEQC-2. Optimization using the nonlinear optimization program PEST brought forward that solid organic carbon and not clay minerals controlled retardation of cations. Cation exchange resulted in spatial separation of Fe(II), Mn(II) and NH4 fronts from the fringe, and thereby prevented possible oxidation of these secondary redox species. Degradation of DOC may happen in the fringe zone. Re-dissolution of methane escaped from the plume and subsequent oxidation is an explanation for absence of previously present nitrate and anaerobic conditions in pristine groundwater above the plume. Stable carbon isotope (delta13C) values of methane confirm anaerobic methane oxidation immediately below the fringe zone, presumably coupled to reduction of sulfate, desorbed from iron oxide. Methane must be the principle reductant consuming soluble electron-acceptors in pristine groundwater, thereby limiting NA for other solutes including organic micro-pollutants at the fringe of this landfill leachate plume.     

Natural attenuation of xenobiotic organic compounds in a landfill leachate plume (Vejen,Denmark)

Demonstration of natural attenuation of xenobiotic organic compounds (XOCs) in landfill leachate plumes is a difficult task and still an emerging discipline within groundwater remediation. One of the early studies was made at the Vejen Landfill in Denmark in the late 1980s, which suggested that natural attenuation of XOCs took place under strongly anaerobic conditions within the first 150 m of the leachate plume. This paper reports on a revisit to the same plume 10 years later. Within the strongly anaerobic part of the plume, 49 groundwater samples were characterized with respect to redox-sensitive species and XOCs. The analytical procedures have been developed further and more compounds and lower detection limits were observed this time. In addition, the samples were screened for degradation intermediates and for toxicity. The plume showed fairly stationary features over the 10-year period except that the XOC level as well as the level of chloride and nonvolatile organic carbon (NVOC) in the plume had decreased somewhat. Most of the compounds studied were subject to degradation in addition to dilution. Exceptions were benzene, the herbicide Mecoprop (MCPP), and NVOC. In the early study, NVOC seemed to degrade in the first part of the plume, but this was no longer the case. Benzyl succinic acid (BSA) was for the first time identified in a leachate plume as a direct indicator, and as the only intermediate of toluene degradation. Toxicity measurements on solid phase-extracted (SPE) samples revealed that toxic compounds not analytically identified were still present in the plume, suggesting that toxicity measurements could be helpful in assessing natural attenuation in leachate plumes.     

The potential application of red mud and soil mixture as additive to the surface layer of a landfill cover system

Red mud, the by-product of aluminum production, has been regarded as a problematic residue all over the world. Its storage involves risks as evidenced by the Ajka red mud spill,an accident in Hungary where the slurry broke free, flooding the surrounding areas. As an immediate remediation measure more than 5 cm thick red mud layer was removed from the flooded soil surface. The removed red mud and soil mixture(RMSM) was transferred into the reservoirs for storage. In this paper the application of RMSM is evaluated in a field study aiming at re-utilizing waste, decreasing cost of waste disposal and providing a value-added product. The purpose was to investigate the applicability of RMSM as surface layer component of landfill cover systems. The field study was carried out in two steps: in lysimeters and in field plots. The RMSM was mixed at ratios ranging between 0 and 50% w/w with low quality subsoil(LQS) originally used as surface layer of an interim landfill cover. The characteristics of the LQS + RMSM mixtures compared to the subsoil(LQS) and the RMSM were determined by physical–chemical, biological and ecotoxicological methods. The addition of RMSM to the subsoil(LQS) at up to 20% did not result any ecotoxic effect, but it increased the water holding capacity. In addition, the microbial substrate utilization became about triple of subsoil(LQS) after 10 months. According to our results the RMSM mixed into subsoil(LQS) at20% w/w dose may be applied as surface layer of landfill cover systems.     

Recovery of foundry sands and iron fractions from an industrial waste landfill

This study was performed to analyse the technical and economical feasibility of a project concerning the recovery of foundry wastes from a landfill. In such a context, an evaluation of the total amount of residues that could be recovered was performed by using the physical chemical characterization of landfilled wastes: molding and core sands, furnace dusts, finishing dusts, muds, calcium hydroxide and refractory slags. Field tests were realized employing both geophysical methods both the digging of trenches.Two cells of the landfill were investigated by means of geophysical methods using magnetic and electromagnetic techniques. The physical and chemical characterization of wastes was employed in order to determine the best geophysical methods to locate the useful fractions of wastes in landfill and to establish the occurring treatment cycle for the recovery of useful fractions.A cost–benefit analysis was performed to evaluate the feasibility of the proposed landfill mining operation.     

Fenton氧化法深度处理垃圾渗滤液的试验研究

采用Fenton氧化法对经生化处理后的垃圾渗滤液进行深度处理。结果表明,Fenton反应最佳工艺条件:初始pH值为3,H2O2加入量为3.0mL/L,FeSO4.7H2O加入量为3.5g/L,反应时间120min。生化处理后的垃圾渗滤液经Fenton氧化法深度处理后,CODCr由处理前的300mg/L,降至处理后的93mg/L,去除率达69.0%,出水水质达到新修订的《生活垃圾填埋场污染控制标准》(GB16889-2008)排放标准。     

沈阳市生活垃圾填埋场现状及场地利用的建议

通过对国内外及沈阳市生活垃圾填埋场现状的分析,论述了沈阳市生活垃圾填埋场场地再利用的技术方法,并提出了垃圾填埋场绿化、稳定化的垃圾开采利用及将渗沥液经反渗透处理后的浓缩液回灌的方式,加速垃圾填埋场稳定化速度的建议。     

Fate and transport of phenol in a packed bed reactor containing simulated solid waste

An assessment of the risk to human health and the environment associated with the presence of organic contaminants (OCs) in landfills necessitates reliable predictive models. The overall objectives of this study were to (1) conduct column experiments to measure the fate and transport of an OC in a simulated solid waste mixture, (2) compare the results of column experiments to model predictions using HYDRUS-1D (version 4.13), a contaminant fate and transport model that can be parameterized to simulate the laboratory experimental system, and (3) determine model input parameters from independently conducted batch experiments. Experiments were conducted in which sorption only and sorption plus biodegradation influenced OC transport. HYDRUS-1D can reasonably simulate the fate and transport of phenol in an anaerobic and fully saturated waste column in which biodegradation and sorption are the prevailing fate processes. The agreement between model predictions and column data was imperfect (i.e., within a factor of two) for the sorption plus biodegradation test and the error almost certainly lies in the difficulty of measuring a biodegradation rate that is applicable to the column conditions. Nevertheless, a biodegradation rate estimate that is within a factor of two or even five may be adequate in the context of a landfill, given the extended retention time and the fact that leachate release will be controlled by the infiltration rate which can be minimized by engineering controls.