Electrokinetic-assisted phytoremediation of polluted sites

人为和自然来源的土壤污染是一个严重的环境问题，在世界范围内日益严重。常见的污染物有重金属、多环芳烃和溶剂。污染物可以通过渗透扩散到周围地区，成为人类和生态受体的健康危害。已经开发了许多技术来修复受污染的场地；然而，它们的适用性往往限于单一类型的污染物或场地条件的狭窄范围。因此，清理受污染场地涉及昂贵和耗时的任务，因为许多场地含有多种污染物。一些修复技术如土壤冲洗和原位冲洗需要引入化学试剂，这些试剂在非均质和低渗透土壤中难以输送。此外，固化和稳定处理是如此强烈，以至于它们极大地改变了土壤的性质。植物修复是一种利用植物修复污染场地的绿色技术。它有几个优点：它可以大面积就地应用，成本低，土壤不会受到重大损害。然而，植物修复对污染场地的恢复是缓慢的，并且只适用于根部可及的深度。为了克服植物修复的局限性，提出了电动力学增强植物修复技术。它包括对污染土壤施加低强度电场，通过电动力学增加污染物的生物利用度，同时污染物被植物去除或降解。近年来的研究表明，电动植物修复技术具有广阔的应用前景。然而，在实地使用该技术之前，还需要进行更多的研究，以评估其功效并提高其效率。太阳能是一种新型的电动增强植物修复能源。本研究计划的目标是：(a)确定该技术的最佳电压和电极配置；(b)评估电动力学在植物根部以外增加修复区域的功效；(c)审查植物物种对补救措施的影响；(d)评估每种植物修复在去除污染物方面的贡献；(e)研究太阳能电池板在电动植物修复中的应用。在研究计划期间进行的实验研究和数值模拟将提供答案，这将导致改进电动植物修复系统的设计，并加快技术的现场应用转移。这一研究项目将有助于加拿大共同努力发展绿色和可持续技术。

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.