Woodman N D, Rees-White T C, Beaven R P, Stringfellow A M, Barker J A
Faculty of Engineering and the Environment, University of Southampton, Southampton SO17 1B, UK..
Faculty of Engineering and the Environment, University of Southampton, Southampton SO17 1B, UK.
J Contam Hydrol. 2017 Aug;203:38-50. doi: 10.1016/j.jconhyd.2017.05.008. Epub 2017 Jun 7.
This paper describes a programme of research investigating horizontal fluid flow and solute transport through saturated municipal solid waste (MSW) landfill. The purpose is to inform engineering strategies for future contaminant flushing. Solute transport between injection/abstraction well pairs (doublets) is investigated using three tracers over five separate tests at well separations between 5m and 20m. Two inorganic tracers (lithium and bromide) were used, plus the fluorescent dye tracer, rhodamine-WT. There was no evidence for persistent preferential horizons or pathways at the inter-well scale. The time for tracer movement to the abstraction wells varied with well spacing as predicted for a homogeneous isotropic continuum. The time for tracer movement to remote observation wells was also as expected. Mobile porosity was estimated as 0.02 (4% of total porosity). Good fits to the tracer breakthrough data were achieved using a dual-porosity model, with immobile regions characterised by block diffusion timescales in the range of about one to ten years. This implies that diffusional exchanges are likely to be very significant for engineering of whole-site contaminant flushing and possibly rate-limiting.
本文描述了一项研究计划，该计划旨在调查水平流体流动以及溶质在饱和城市固体废弃物（MSW）填埋场中的运移情况。目的是为未来污染物冲洗的工程策略提供依据。在5米至20米的井间距下，通过五个单独的测试，使用三种示踪剂研究了注入/抽提井对（双井）之间的溶质运移。使用了两种无机示踪剂（锂和溴化物），外加荧光染料示踪剂罗丹明-WT。在井间尺度上，没有证据表明存在持续的优先水平层或路径。示踪剂移动到抽提井的时间随井间距变化而变化，正如对均匀各向同性连续介质所预测的那样。示踪剂移动到远程观测井的时间也符合预期。流动孔隙率估计约为0.02（约占总孔隙率的4%）。使用双孔隙度模型对示踪剂突破数据进行了良好拟合，其中非流动区域以约一到十年范围内的块体扩散时间尺度为特征。这意味着扩散交换对于整个场地污染物冲洗工程可能非常重要，并且可能是限速因素。
