Quantifying macroscopic flow and transport in the unsaturated zone to address the long-term contaminant burden of waste repositories.

量化非饱和区的宏观流动和运输，以解决废物储存库的长期污染物负担。

• 批准号: EP/R04242X/1
• 负责人: William Powrie
• 金额: $ 104.83万
• 依托单位: University of Southampton
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2018
• 资助国家: 英国
• 起止时间: 2018 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FR04242X%2F1
• 关键词: Quantifying; macroscopic; flow; transport; unsaturated

The usual way of managing solid waste in the UK has been landfill. We have more than 20,000 sites, containing 6 billion tonnes of waste, which are now full up. Landfills can cause major environmental problems, especially when water (from rain or streams) gets in and mixes with the waste to form a liquid called 'leachate'. If leachate escapes into the environment it can pollute ground and surface water, damage eco-systems and contaminate drinking water.Modern landfill sites are containment systems, sometimes called 'dry tombs'. Plastic membranes line the base and the sides to control how much leachate seeps out. A cap reduces the amount of rainfall entering to reduce how much leachate is formed. Leachate which does form is retained at the base, where it can be collected and treated.After landfilling at a site has stopped, it is covered and enters a management phase known as 'aftercare'. During aftercare, leachate needs to be collected and treated for as long as it presents a pollution hazard. Unfortunately, aftercare periods for modern landfills are measured in centuries. The engineered containment system has to keep working for all this time, along with active environmental control systems for gas and leachate extraction or treatment. Extended aftercare periods cause problems for operators, regulators and society, and are unacceptable in terms of sustainability.A unique project in the Netherlands aims to rapidly improve leachate quality at three demonstration landfills so that they can be brought out of aftercare within the next decade. The project also aims to ensure that future emissions of leachate will be acceptably low - for ever, without any human intervention. If the project succeeds, it will lead to much more sustainable and cost effective methods for landfill aftercare.Our research aims to provide some of the science required to underpin the project. It will be undertaken at the de Kragge landfill, where the operator will recirculate leachate and water through the waste. This will flush contaminants out into the leachate, which will then be treated outside the landfill. The success of this type of treatment depends on how the water or leachate flows through the landfill. If the flow is evenly distributed, the waste will be flushed more uniformly than if preferential flow paths allow the liquid to bypass some of the waste. (This is why it is sometimes possible still to read newspapers that have been buried in a landfill for 40 years). The spacing of preferential flow paths is critical. We calculate that if the flow paths are less than 0.5 m apart, contaminants will diffuse out of the waste fast enough to allow clean-up within about a decade. Flow paths that are more than 1 m apart are likely to limit the release of contaminant from the waste to the extent that a landfill might safely be brought out of aftercare before all the contaminant has been removed.Our research will focus on understanding the nature of liquid flow and flow paths within the landfill, and their influence on landfill clean-up. We will install monitoring systems that can differentiate, at a scale of about 0.5 m, between flow occurring in preferential flow paths and flow occurring more evenly within the unsaturated zone of the landfill. Chemical tracers will be injected into the operator's leachate recirculation system, and we will monitor their flow through the waste. After interpreting the tracer data, we will develop and verify a suite of different models that track flow of contaminants and describe landfill clean-up. We will test a range of model concepts against our new data, to identify those that work best. These will then provide a framework for understanding the performance of the Dutch landfill flushing project and for evaluating any residual risks. The models will also provide a scientific basis for optimising the engineering of flushing, and the management of waste repositories worldwide.

英国处理固体废物的常用方法是填埋。我们有超过 20,000 个场地，容纳了 60 亿吨废物，目前已满。垃圾填埋场可能会造成重大环境问题，尤其是当水（来自雨水或溪流）进入并与废物混合形成称为“渗滤液”的液体时。如果渗滤液泄漏到环境中，就会污染地下水和地表水，破坏生态系统并污染饮用水。现代垃圾填埋场采用遏制系统，有时称为“干墓”。塑料膜排列在底部和侧面，以控制渗滤液的渗出量。盖子可以减少进入的降雨量，从而减少渗滤液的形成量。形成的渗滤液被保留在基地，在那里可以收集和处理。在某个地点的垃圾填埋停止后，将其覆盖并进入称为“善后处理”的管理阶段。在善后处理过程中，只要渗滤液存在污染危害，就需要收集和处理。不幸的是，现代垃圾填埋场的善后处理周期以数百年为单位。工程密封系统必须始终保持工作状态，以及用于气体和渗滤液提取或处理的主动环境控制系统。延长的善后处理期会给运营商、监管机构和社会带来问题，并且在可持续性方面是不可接受的。荷兰的一个独特项目旨在快速提高三个示范垃圾填埋场的渗滤液质量，以便它们能够在未来十年内摆脱善后处理。该项目还旨在确保未来渗滤液的排放量将永远保持在可接受的低水平，无需任何人为干预。如果该项目成功，它将带来更加可持续和更具成本效益的垃圾填埋场善后处理方法。我们的研究旨在提供支持该项目所需的一些科学知识。该项目将在德克拉格垃圾填埋场进行，运营商将通过废物再循环渗滤液和水。这会将污染物冲入渗滤液中，然后在垃圾填埋场外进行处理。这种处理的成功取决于水或渗滤液如何流经垃圾填埋场。如果流量均匀分布，则与优先流动路径允许液体绕过一些废物相比，废物将被更均匀地冲洗。 （这就是为什么有时仍然可以阅读被埋在垃圾填埋场 40 年的报纸）。优先流路的间距至关重要。我们计算出，如果流路间隔小于 0.5 m，污染物将从废物中扩散出来的速度足够快，足以在大约十年内完成清理。相距超过 1 m 的流路可能会限制废物中污染物的释放，以便在所有污染物被清除之前，垃圾填埋场可以安全地从善后处理中移出。我们的研究将侧重于了解废物的性质垃圾填埋场内的液体流动和流动路径及其对垃圾填埋场清理的影响。我们将安装监测系统，能够以约 0.5 m 的尺度区分优先流动路径中发生的流动和垃圾填埋场非饱和区域内更均匀发生的流动。化学示踪剂将被注入运营商的渗滤液再循环系统中，我们将监测它们在废物中的流量。在解释示踪剂数据后，我们将开发并验证一套不同的模型，用于跟踪污染物的流动并描述垃圾填埋场的清理情况。我们将根据新数据测试一系列模型概念，以确定最有效的模型概念。这些将为了解荷兰垃圾填埋场冲洗项目的绩效和评估任何残余风险提供一个框架。该模型还将为优化冲刷工程和全球废物储存库的管理提供科学依据。

项目成果

Causes of High Internal Pore Pressure in a Downward-Draining MSW Landfill

下排垃圾填埋场内部孔隙压力高的原因

• DOI: 10.1061/jggefk.gteng-11520
• 发表时间: 2024-03-01
• 期刊: Journal of Geotechnical and Geoenvironmental Engineering
• 影响因子: 3.9
• 作者: R. Beaven;Jim White;N. Woodman;T. Rees;J. Smethurst;A. Stringfellow;William Powrie;Twan Kanen
• 通讯作者: Twan Kanen

Spatial variability of leachate tables, leachate composition and hydraulic conductivity in a landfill stabilized by in situ aeration

通过原位曝气稳定的垃圾填埋场中渗滤液表、渗滤液成分和水力传导率的空间变异性

• 发表时间: 2021
• 作者: Gebert; J
• 通讯作者: J