Electrokinetic-assisted phytoremediation of polluted sites

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The contamination of soils from anthropogenic and natural sources is a serious environmental problem that is growing around the world. Common pollutants are heavy metals, polycyclic aromatic hydrocarbons and solvents. Pollutants can spread by seepage to the surrounding areas and become a health hazard for human and ecological receptors. Numerous technologies have been developed to remediate contaminated sites; however, their applicability is often limited to a single type of contaminant or a narrow range of site conditions. The cleanup of contaminated sites therefore involves expensive and time-consuming tasks as many sites contain several pollutants. Some remediation technologies such as soil washing and in situ flushing require introduction of chemical reagents, which are difficult to deliver in heterogeneous and low permeability soils. Also, solidification and stabilization treatment are so intense that they dramatically change the properties of the soil. Phytoremediation is a green technology for restoring contaminated sites using live plants. It has several advantages: it can be applied in situ over large areas, the cost is low, and the soil does not undergo significant damages. The restoration of a contaminated site by phytoremediation however, is a slow and only applicable for depths within the reach of the roots. Electrokinetic-enhanced phytoremediation has been proposed to overcome the limitations of phytoremediation. It consists of the application of a low intensity electric field to the contaminated soil to increase the bioavailability of the contaminant by electrokinetics while the contaminant is removed or degraded by the plant. Recent studies have shown very promising potential for electrokinetic-phytoremediation technology. However, more research is necessary in order to assess the efficacy and improve the efficiency of the technology before it can be used in situ. Solar energy is an innovative power source for electrokinetic-enhanced phytoremediation. The objectives of this program of research are to: (a) identify optimum voltage and electrode configurations for the technology; (b) evaluate the efficacy of electrokinetics to increase the zone of remediation beyond the plant roots; (c) examine the influence of plant species on the remediation; (d) evaluate the contribution by each phytoremediation in contaminant removal; and (e) examine the use of solar panels for electrokinetic-phytoremediation. The experimental study and numerical simulation carried out during the research program will provide answers that will lead to an improved design of electrokinetic-phytoremediation systems and expedite the transfer of the technology for field applications. This program of research will contribute to Canada's concerted effort to develop green and sustainable technologies.