Electrokinetic-assisted phytoremediation of polluted sites

来自人为和自然来源的土壤污染是一个严重的环境问题，在世界各地都在增长。常见的污染物是重金属、多环芳烃和溶剂。污染物可以通过渗漏传播到周围地区，并成为对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狭窄的场地条件。因此，清理受污染的场地涉及昂贵和耗时的任务，因为许多场地含有几种污染物。一些修复技术，如土壤清洗和原位冲洗，需要引入化学试剂，这些试剂在非均质和低渗透土壤中很难输送。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活植物修复受污染场地的绿色技术。它具有大面积现场应用、成本低、不会对土壤造成重大破坏等优点。然而，通过植物修复修复受污染的场地是一个缓慢的过程，而且只适用于根部可以触及的深处。电动增强植物修复技术是为了克服植物修复技术的局限性而提出的。它包括对受污染的土壤施加低强度电场，以提高污染物的生物利用度，同时通过电动作用使污染物被植物去除或降解。最近的研究表明，电动-植物修复技术具有很大的潜力。然而，在该技术可以在现场使用之前，还需要进行更多的研究，以评估其效果并提高其效率。太阳能是电动强化植物修复的一种创新能源。这项研究计划的目标是：(A)确定该技术的最佳电压和电极配置；(B)评估电动力学在扩大植物根部以外的修复区域方面的有效性；(C)检查植物物种对修复的影响；(D)评估每种植物修复在去除污染物方面的贡献；以及(E)检查太阳能电池板用于电动-植物修复的情况。在研究方案期间进行的实验研究和数值模拟将提供答案，从而改进电动植物修复系统的设计，并加快将技术转让给实地应用。这项研究计划将有助于加拿大共同努力开发绿色和可持续的技术。

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.