Assessment of landfill final covers employing contaminated soils

点击翻译按钮获取中文摘要

Contaminated soils have limited options for re-use and are destined to be landfilled. Current regulations allow for lightly contaminated soils to be reused anywhere in final cover for landfills, with the use of moderately contaminated soils being more restricted. Although in a previous study we have found that run-off from experimental final covers containing moderately contaminated do not pose an immediate environmental concern, long-term contaminant vertical and horizontal transport of these soils to the surrounding environment needs to be investigated if moderately contaminated soils are to be included in final covers. This research project proposes to decommission five fully instrumented experimental covers that were constructed at the St-Nicephore landfill in 2018. This project provides the unique opportunity to exhume soil in a methodical approach to: (1) develop a contaminant profile throughout the experimental covers; and (2) establish the soil characteristics in-situ to be used in computer modelling of seepage through landfill covers. Laboratory experiments will be performed to: (1) develop unsaturated soil characteristics and assess changes in the experimental cover and compare values to initial construction values; and (2) assess long-term contaminant transport patterns. These laboratory and field results will be used in computer modelling of seepage and contaminant transport. The expected outcomes of the project are to re-evaluate the existing regulations for re-utilisation of contaminated soils for final cover in landfills. Expected benefits are: (1) reduction of soil landfilled; and (2) decrease of quarrying clean soil for use at landfill sites. This project is a collaborative effort with WM Quebec. The use of contaminated soils constitutes a unique business opportunity for the company and most likely for all stakeholders in the sustainable management of residual materials industry. As a result, it is an undeniable environmental and economic gain for Canada.