A quantitative approach to assessing the technical and economic performance of source containment options for contaminated aquifers

The containment of contaminant plumes to protect groundwater from pollution is recognized as a frequent need in brownfield redevelopment. Plume containment can be physical, with slurry walls, jet grouting etc., or hydraulic, with wells capturing the subsurface flow that crosses the contaminated front (Pump & Treat), or a combination of both types. The choice of the most suitable technique is a difficult task, since various aspects must be taken into consideration. In this paper, we present a framework for evaluating barriers in terms of effectiveness and efficiency, along with a simplified approach for the evaluation of capital and operational costs. The contaminant mass discharge escaping from the containment system is a robust indicator of its effectiveness, and can be derived from modelling results. The abstracted water flowrate is a key indicator of the efficiency and sustainability of each option, especially in the long term. The methodology is tested in a simplified case study and in a real one, highlighting the relevance of modelling results in guiding the choice and design of contaminant source containment systems.