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.

英国管理固体废物的通常方式是垃圾填埋场。我们有20,000多个网站，其中包含60亿吨废物，现在已经充满了。垃圾填埋场可能会引起重大的环境问题，尤其是当水（从雨水或溪流中）与废物混合以形成一种称为“浸出物”的液体时。如果渗滤液逃到环境中，它会污染地面和地表水，损坏生态系统和污染的饮用水。现代垃圾填埋场是遏制系统，有时称为“干墓”。塑料膜在底座和侧面排成一列，以控制渗出量渗出多少。帽子减少了降雨量的数量，以减少形成渗滤液的数量。浸出的渗滤液保留在可以收集和处理的基地上。垃圾填埋场停止，被覆盖并进入一个被称为“ Aftercare”的管理阶段。在余后保健期间，只要出现污染危害，就需要收集和处理渗滤液。不幸的是，几个世纪以来，对现代垃圾填埋场的护理期进行了衡量。工程的遏制系统必须一直保持工作，以及用于气体和渗滤液提取或处理的主动环境控制系统。延长的后期护理时期会给运营商，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在三个示范垃圾填埋场的三个示范垃圾填埋场中迅速提高浸出质量，以便在下一十年内将其带出后期的护理。该项目还旨在确保未来的渗滤液排放量将是可以接受的 - 永远不会在没有任何人类干预的情况下。如果该项目成功，它将为垃圾填埋场提供更具可持续性和成本效益的方法。我们的研究旨在提供支撑该项目所需的一些科学。它将在De Kragge垃圾填埋场进行，在那里操作员将通过废物再循环渗滤液和水。这将冲入浸出液中，然后将其在垃圾填埋场外进行处理。这种治疗的成功取决于水或渗滤液如何流过垃圾填埋场。如果流动均匀分布，则与优先流动路径允许液体绕过一些废物相比，废物的冲洗将更加均匀。 （这就是为什么有时仍然可以阅读被埋葬40年的报纸的原因）。优先流动路径的间距至关重要。我们计算出，如果流动路径相距不到0.5 m，则污染物将迅速地从废物中扩散出来，以便在大约十年内清理。相距超过1 m的流动路径可能会限制污染物从废物的释放，以至于可以在清除所有污染物之前可以安全地将垃圾填埋场带出垃圾填埋场。我们将安装可以在优先流动路径中发生的流量和流量更均匀地发生在垃圾填埋场的不饱和区域内的流动之间，以大约0.5 m的尺度区分监测系统。化学示踪剂将被注入操作员的渗滤液再循环系统，我们将监视它们通过废物的流动。解释示踪剂数据后，我们将开发并验证一套不同的模型，这些模型跟踪污染物的流动并描述垃圾填埋场的清理。我们将针对我们的新数据测试一系列模型概念，以确定那些效果最佳的模型概念。然后，这些将提供一个框架，以了解荷兰垃圾填埋场项目的性能并评估任何剩余风险。这些模型还将提供科学基础，以优化潮红的工程以及全球废物存储库的管理。

项目成果

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

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