Are impermeable curtains necessary for a groundwater contaminant remediation project?

Constructing impermeable curtains to contain contaminant in aquifers is a costly and complex process that can impact the structure integrity of aquifer systems. Are impermeable curtains necessary for a groundwater contaminant remediation project? This study evaluates the necessity of impermeable curtains for groundwater contaminant remediation projects. Specifically, it considers remediation efforts based on the pump and treat (PAT) technique under various hydrogeological conditions and contaminant properties, comparing the total remediation cost and effectiveness. To further investigate, a multi-objective simulation and optimization model, utilizing the Multi-Objective Fast Harmony Search (MOFHS) algorithm, was employed to identify optimal groundwater remediation system designs that without impermeable curtains. Both a two-dimensional (2-D) hypothetical example and a three-dimensional (3-D) field example were used to assess the necessity of constructing impermeable curtains. The 2-D hypothetical example demonstrated that the installation of impermeable curtain is justified only when the dispersivity (α_L) of the contaminant reaches 100 meters. In most cases, particularly at sites with porosity (n) under 0.3, alternative, more cost-effective, and efficient remediation strategies may be available, making impermeable barriers unnecessary. The optimization results of the 3-D field example further corroborate the conclusions derived from the 2-D hypothetical example. These findings provide valuable guidance for more scientifically informed, reasonable, and cost-effective groundwater contaminant remediation projects.