University of Skikda, Algeria; Laboratoire d'etude des Transferts en Hydrologie et Environnement (LTHE), Université Grenoble Alpes, BP 53 38041 Grenoble Cedex 09, France.
Laboratoire d'etude des Transferts en Hydrologie et Environnement (LTHE), Université Grenoble Alpes, BP 53 38041 Grenoble Cedex 09, France.
Waste Manag. 2017 May;63:122-130. doi: 10.1016/j.wasman.2016.07.048. Epub 2016 Aug 21.
During the lifespan of a Municipal Solid Waste landfill, its leachate drainage system may get clogged. Then, as a consequence of rainfall, leachate generation and possibly leachate injection, the moisture content in the landfill increases to the point that a leachate mound could be created. Therefore, pumping the leachate becomes a necessary solution. This paper presents an original analysis of leachate pumping and injection in an instrumented well. The water table level around the well is monitored by nine piezometers which allow the leachate flow behaviour to be captured. A numerical model based on Richards equation and an exponential relationship between saturated hydraulic conductivity and depth is used to analyze the landfill response to pumping and injection. Decreasing permeability with depth appears to have a major influence on the behaviour of the leachate flow. It could have a drastic negative impact on the pumping efficiency with a maximum quasi-stationary pumping rate limited to approximately 1m/h for the tested well and the radius of influence is less than 20m. The numerical model provides a reasonable description of both pumping and injection tests. However, an anomalous behaviour observed at the transition between pumping and recovery phases is observed. This could be due to a limitation of the Richards model in that it neglects the gas phase behaviour and other double porosity heterogeneous effects.
在城市固体废物填埋场的生命周期内，其渗滤液排水系统可能会堵塞。然后，由于降雨、渗滤液的产生和可能的渗滤液注入，填埋场内的水分含量增加到可能形成渗滤液山丘的程度。因此，泵送渗滤液成为一种必要的解决方案。本文对仪器井中的渗滤液泵送和注入进行了原始分析。通过九个测压管监测井周围的地下水位，从而可以捕获渗滤液的流动行为。基于 Richards 方程和饱和水力传导率与深度之间的指数关系的数值模型用于分析填埋场对泵送和注入的响应。随着深度的增加，渗透率的降低似乎对渗滤液流动的行为有重大影响。它可能会对泵送效率产生巨大的负面影响，对于测试井，最大准稳定泵送速率限制在约 1m/h，影响半径小于 20m。数值模型对泵送和注入测试都提供了合理的描述。然而，在泵送和恢复阶段之间的过渡期间观察到异常行为。这可能是由于 Richards 模型的局限性，因为它忽略了气相行为和其他双重孔隙非均质效应。
