Evaluating the feasibility of hydraulic and physical barriers at contaminated sites by means of multicriteria analysis

Controlling contaminant plumes in groundwater using pump and treat or hydraulic and physical barriers is a common practice to contain and reduce solute contaminants in remediation activities. Recent evolution in engineering techniques also allowed to extend the number of solutions that can be designed and set in practice. As such, the decision-making process assumes great importance in leading the selection of the best suitable technology for a certain case study. This process has to take into account technical, environmental and socioeconomic factors. This paper presents the results of a research project aimed at defining a multi-criteria procedure analysis to support the decision-making process in the barrier technology selection, taking into account technical, economic, social and environmental factors. A multi-criteria analysis methodology has been defined to provide a quantitative tool to guide the selection of the best suitable technology concerning a specific case. The methodology was applied to a real case, selected from many case studies based on data availability and quality, in order to verify the effectiveness of the procedure in evaluating the alternative selections and to highlight the differences between the results of the multi-criteria analysis and the real engineers choices. A sensitivity analysis was performed to analyze the influence of each criterion on the final result of the study. With this paper we aim to start a discussion to deepen the decision making process, in order to develop methodologies allowing to chose the best solution without subjective evaluations.