应用反渗透技术处理垃圾填埋场渗滤液

垃圾填埋场渗滤液属于高浓度氨氮废水，其水量、水质特性变化大，成分复杂，因此较难处理。反渗透分离技术能有效截留垃圾渗滤液中溶解态的有机和无机污染物。采用三级反渗透处理垃圾渗滤液工艺处理后的出水水质，能够满足《生活垃圾填埋污染控制标准》（DB16889-2008）要求，并把渗滤液浓缩液回灌于填埋场。     

准好氧填埋技术在城市垃圾处理中的应用

准好氧垃圾填埋技术在近年得到了国内外的广泛应用。其原理是将排气管与渗滤液收集管相通，利用自然通风，使外部空气因填埋场内微生物发酵产生的热量形成的热对流而通过排水管自然进入填埋场内。使填埋场内维持好氧状态，从而加快垃圾的分解，改善渗滤液水质，降低有害气体的发生量，极大的改善了填埋场周围的环境。     

矿化垃圾作回灌型准好氧填埋场日覆盖材料的适宜性研究

本文在对矿化垃圾的基本性质进行测定的基础上,将其作为填埋场覆盖材料进行室内模拟实验.结果显示:经过筛分后的矿化垃圾细料可作为回灌型准好氧填埋场的日覆盖材料,除了具有日覆盖材料的常规功能外,还有净化渗滤液的能力;矿化垃圾对渗滤液中污染物的净化能力优于普通砂土;矿化垃圾作日覆盖材料的最佳粒度为d≤3mm,最优厚度为13cm,双层结构对污染物的净化能力优于单层结构.所以矿化垃圾是一种性能良好的日覆盖替代材料.     

渗滤液回灌在实际应用中应注意的问题

本文介绍了垃圾填埋场渗滤液回灌的机理、优缺点,“干填埋”与“湿填埋”之间的区别。渗滤液回灌可增加填埋废物的含水率,加快垃圾的降解速率,减少渗滤液的处理时间,提高填埋气中甲烷的含量,加速填埋场稳定化进程。鉴于以上这些优点,渗滤液回灌作为一种渗滤液处理方式将会有极大的应用前景。但在实际应用中回灌的渗滤液容易泄漏而导致地下水污染,这是影响渗滤液回灌广泛应用的主要原因。为了避免使地下水受污染,本文总结和分析了渗滤液回灌在实际应用中应注意的问题。     

垃圾填埋场水力学特性的研究进展

本文对填埋场渗滤液产生和运移的水力学特性的研究成果进行了总结，建立在填埋垃圾均质各向同性假设基础上的渗滤液运移模型不能满足日后生物反应器填埋场渗滤液回灌系统的设计和操作运行需要，基于填埋垃圾非均质各向异性的填埋场水力学特性将是今后研究的重点。     

回灌型准好氧填埋场渗滤液中COD浓度的预测模型探讨

基于进行的室内模拟试验，推导了回灌型准好氧填埋场COD浓度计算模型，并通过模拟试验结果确定了模型参数。结果表明，模型的相关系数为0．91，该模型可用于该类填埋场COD浓度的预测。本研究可为回灌型准好氧填埋场的设计提供依据。     

厌氧-准好氧型填埋的渗滤液实验研究

通过室内模拟试验，在渗滤液回灌的厌氧填埋柱基本进入稳定状态后，改用准好氧运行方式。同时监测了渗滤液中有机物浓度以压温度、pH值的变化。改变模拟垃圾柱的运行方式两个月以后。氨氯浓度由2000mg／L迅速下降至101．48mg／L，试验结果显示，准好氧运行方式可以解决生物反应器填埋场进入稳定阶段后存在的氨氮浓度高的问题，加速填埋场的稳定。     

城市垃圾渗滤液场内循环处理的探讨

本文对城市垃圾渗滤液的产生量、水质特征及其影响因素进行了分析，介绍了当前国内外垃圾渗滤水场内循环处理的两大研究流派-以欧美国家为主的生物反应器填埋技术和以日本为主的循环式准好氧填埋技术。根据我国城市垃圾有机物含量高的特点，提出了适合我国国情的、将准好氧填埋技术与生物反应器填埋技术特点相结合的城市垃圾填埋场渗波液场内循环处理的设计思路。     

垃圾填埋场渗滤液回灌技术研究

垃圾填埋场会产生大量的垃圾渗滤波,垃圾渗滤液回灌可以利用填埋场内微生物加速分解其中的有机物,同时可以利用回灌控制填埋场的含水量,促进填埋场的稳定.本文概括了渗滤液回灌处理的理论基础、工艺流程,分析了回灌技术的影响因素,并对表面回灌和地下回灌方式进行了比较,指出了推广应用垃圾渗滤液回灌处理技术需要解决的几点问题.     

生物反应器填埋场渗滤液及其处理对策

根据垃圾的降解和稳定机理分析了生物反应器填埋场渗滤液的动态变化规律，并对其处理对策进行了探讨。生物反应器填埋场前期产生的渗滤液可全部回灌，后期再根据实际情况排放处理部分过量的渗滤液。在对渗滤液水量和水质全面直观认识后，再对生物反应器填埋场渗滤液处理工艺进行针对性的选择和设计，并宜采用物化法处理方式。     

Quality and Quantity of Leachate in Aerobic Pilot-Scale Landfills

In this study, two pilot-scale aerobic landfill reactors with (A1) and without (A2) leachate recirculation are used to obtain detailed information on the quantity and quality of leachate in aerobic landfills. The observed parameters of leachate quality are pH, chloride (Cl⁻), chemical oxygen demand (COD), biological oxygen demand (BOD), total Kjeldahl nitrogen (TKN), ammonia nitrogen (NH₃-N), and nitrate (NO₃^–-N). pH values of the leachate increased to 7 after 50 days in reactor A1 and after 70 days in reactor A2. Cl⁻ concentrations increased rapidly to 6100 (A1) and 6900 (A2) mg/L after 80 days, from initial values of 3000 and 2800 mg/L, respectively. COD and BOD values decreased rapidly in the A1 landfill reactor, indicating the rapid oxidation of organic matter. The BOD/COD ratio indicates that leachate recirculation slightly increases the degradation of solid waste in aerobic landfills. NH₃-N concentrations decreased as a result of the nitrification process. Denitrification occurred in parts of the reactors as a result of intermittent aeration; this process causes a decrease in NO₃⁻ concentrations. There is a marked difference between the A1 and A2 reactors in terms of leachate quantity. Recirculated leachate made up 53.3% of the leachate generated from the A1 reactor during the experiment, while leachate quantity decreased by 47.3% with recirculation when compared with the aerobic dry landfill reactor.     

The effects of leachate recirculation with supplemental water addition on methane production and waste decomposition in a simulated tropical landfill

In order to increase methane production efficiency, leachate recirculation is applied in landfills to increase moisture content and circulate organic matter back into the landfill cell. In the case of tropical landfills, where high temperature and evaporation occurs, leachate recirculation may not be enough to maintain the moisture content, therefore supplemental water addition into the cell is an option that could help stabilize moisture levels as well as stimulate biological activity. The objectives of this study were to determine the effects of leachate recirculation and supplemental water addition on municipal solid waste decomposition and methane production in three anaerobic digestion reactors. Anaerobic digestion with leachate recirculation and supplemental water addition showed the highest performance in terms of cumulative methane production and the stabilization period time required. It produced an accumulated methane production of 54.87 l/kg dry weight of MSW at an average rate of 0.58 l/kg dry weight/d and reached the stabilization phase on day 180. The leachate recirculation reactor provided 17.04 l/kg dry weight at a rate of 0.14l/kg dry weight/d and reached the stabilization phase on day 290. The control reactor provided 9.02 l/kg dry weight at a rate of 0.10 l/kg dry weight/d, and reached the stabilization phase on day 270. Increasing the organic loading rate (OLR) after the waste had reached the stabilization phase made it possible to increase the methane content of the gas, the methane production rate, and the COD removal. Comparison of the reactors' efficiencies at maximum OLR (5 kgCOD/m(3)/d) in terms of the methane production rate showed that the reactor using leachate recirculation with supplemental water addition still gave the highest performance (1.56 l/kg dry weight/d), whereas the leachate recirculation reactor and the control reactor provided 0.69 l/kg dry weight/d and 0.43 l/kg dry weight/d, respectively. However, when considering methane composition (average 63.09%) and COD removal (average 90.60%), slight differences were found among these three reactors.     

Physical properties of industrial wastes: laboratory tests

This article describes some laboratory tests performed on each kind of sludge located in an industrial wastes landfill. Measured physical properties are: field capacity, hydraulic permeability, saturation water content, effective porosity and particle-size distribution. The laboratory apparatus is described; the obtained results are analyzed to point out the possible correlations among the examined parameters. The aim of this work is to provide a data bank for industrial wastes landfills useful to perform some applications such as the evaluation of the produced leachate quantity for landfills whose wastes are similar to the ones here considered.     

Evaluation of leachate recirculation on nitrous oxide production in the Likang Landfill,China

Landfill leachate recirculation is efficient in reducing the leachate quantity handled by a leachate treatment plant. However, after land application of leachate, nitrification and denitrification of the ammoniacal N becomes possible and the greenhouse gas nitrous oxide (N2O) is produced. Lack of information on the effects of leachate recirculation on N2O production led to a field study being conducted in the Likang Landfill (Guangzhou, China) where leachate recirculation had been practiced for 8 yr. Monthly productions and fluxes of N2O from leachate and soil were studied from June to November 2000. Environmental and chemical factors regulating N2O production were also accessed. An impermeable top liner was not used at this site; municipal solid waste was simply covered by inert soil and compacted by bulldozers. A high N2O emission rate (113 mg m-2 h-1) was detected from a leachate pond purposely formed on topsoil within the landfill boundary after leachate irrigation. A high N2O level (1.09 micrograms L-1) was detected in a gas sample emitted from topsoil 1 m from the leachate pond. Nitrous oxide production from denitrification in leachate-contaminated soil was at least 20 times higher than that from nitrification based on laboratory incubation studies. The N2O levels emitted from leachate ponds were compared with figures reported for different ecosystems and showed that the results of the present study were 68.7 to 88.6 times higher. Leachate recirculation can be a cost-effective operation in reducing the volume of leachate to be treated in landfill. However, to reduce N2O flux, leachate should be applied to underground soil rather than being irrigated and allowed to flow on topsoil.     

城市垃圾填埋场渗滤液处理工艺综述

城市垃圾对环境的影响越来越严重，垃圾填埋导致垃圾渗滤液的大量产生，渗滤液中含有大量的有机物、大量的病菌、病毒、寄生虫等以及一些有毒有害的物质，若渗滤液不加以妥善处理、肆意排放，必将对地下水、地表水构成严重威胁，因此垃圾渗滤液的有效处理就成为一个亟待解决的问题。本文对城市垃圾填埋场渗滤液的处理工艺进行了分析和探讨，介绍了国内外垃圾渗滤液处理的主要技术，包括土地处理法、生物法和物化法，并对电解法处理垃圾渗滤液进行了详细的介绍。     

GROUND WATER HYDRAULICS CONSIDERATIONS REGARDING LANDFILLS1

ABSTRACT: Landfill siting and design guidelines or regulations differ from state to state. Most include hydrogeological criteria, referring to hydraulic conductivities, aquifers, ground water flow patterns, contaminant travel times, and distance between landfill and sensitive targets for contaminants, etc. However, almost all of the existing hydrogeological guidelines are incomplete, inconsistent, or both. The aquitard between landfill and regional aquifer frequently offers less resistance to leachate migration than compliance with regulations may suggest. Residence times of leachate, that makes it through the landfill liner, is often overestimated. Monitoring wells in the regional aquifer are unreliable detectors of local leaks in a landfill. If a landfill does leak, costly aquifer restoration is called for. For traditional landfill designs, ground water monitoring considerations suggest the siting over homogeneous sand and gravel aquifers, rather than over complex till environments. An alternative landfill design criterion is suggested, which is based on a negative hydraulic gradient underneath the landfill. This design guarantees ground water protection, simplifies landfill monitoring, and generally enhances the landfill economy.     

Critical review for the quantification of leachate production: Evaluation example for the “Oum Azza” public landfill in Rabat city,Morocco

The estimation of leachate quantities produced in landfills is necessary to dimension the treatment plants allowing to reduce the polluting load of these effluents and consequently avoid their negative impacts on the environment. Different leachate quantification methods were used in this study to assess the leachate volume produced at the Oum Azza landfill. The water balance method give comparable estimations of leachate production to the Ouled Berjal landfill ratio. The first method showed average values between 487 and 495 m³/day for 2015, 2018, and 2019, and at the same time, the second method gave values between 470 and 477 m³/day for the same years. In contrast, the World Bank ratio showed high values that vary between 2260 and 2295 m³/day for 2015, 2018, and 2019. The on-site data and the statistical analysis showed us that the World Bank ratio is not adapted for the estimation of the leachates produced in Oum Azza landfill, while the water balance and the ratio of Ouled Berjal landfill allowed to give comparable results to reality.