Conception d'un outil d'aide à la décision en phytoremédiation

Abstract

In Québec, contaminated sites must be rehabilitated according to the Environment Quality Act (EQA). Amongst decontamination technologies, phytoremediation consists in using plants to degrade, to extract or to stabilize soils contaminants. This relatively new method is complex since it involves many interrelated parameters. Thus, it remains difficult to evaluate its potential and mistakes are often made. Furthermore, because various stakeholders are involved, the decision-making process is rather tedious. Therefore, this thesis proposes the design of a decision-making tool according to two topics: (1) the estimation of phytoremediation time required to reach a given generic criterion and (2) the facilitation of cost planning. The object-oriented methodology has allowed to categorize information into data sheets, hence facilitating the understanding of the problem at hand. For its first version, this tool was designed using the conditions in the province of Québec (legislation, climate, etc.) and the phytoextraction of cadmium by ‘Fish Creek’ willow cultivar (Salix purpurea). An algorithm has been elaborated for the estimation of time using a basic mathematical equation and two adjustment coefficients (one for soil pH, the other for growing degree days). A case study, realised with data from the Valcartier site has allowed to observe that on average, the tool estimates phytoremediation times slightly higher than field times. However, it has not been possible to draw a genuine conclusion to this effect because of the restrictive number of samples. Nevertheless, a sensitivity analysis has allowed to understand the most impacting parameters on phytoremediation time. Regarding the economical aspect, two affecting parameters have been studied: soil pH and the type of substrate. A cost summary has been presented including these parameters in order to serve as a typical example for cost planning of a phytoremediation project. The tool has been developed for only one specific case, but concrete measures have been taken to facilitate future improvements. The principal objective has been reached in the measure that the tool helps the decision-making process by illustrating the context of phytoremediation, by informing the end-user and by pointing out important data to collect. Beyond expectations, this tool also acts as a means of training and of communication for all stakeholders.

Date	4 Nov 2015
Original language	French
Awarding Institution	École de technologie supérieure
Supervisor	Robert Hausler (Supervisor) & Michel Labrecque (Co-supervisor)