SBIR: Phase II: Removal of Contaminants from Soil Using an Enhanced Phytoextraction Process

这个小企业创新研究第二阶段项目描述了一种新的方法，通过结合土壤的植物修复和电动修复过程，从土壤中原位去除污染物。植物修复是一种低成本、低维护的土壤修复技术，可应用于重金属、放射性核素和有机污染物污染土壤的治理。然而，其应用仅限于表面污染，因为清除深度严格取决于植物根部的长度。 就污染物迁移而言，这也是一种被动技术。污染物在土壤中的移动完全由缓慢的植物根系吸力引起，因此污染物去除的效率取决于植物根系在土壤次表面中的延伸。第一阶段开发的新的组合电动植物修复技术利用电场在土壤中诱导的电动效应，以实现污染物在根际的有效运输，并提高植物根部的金属积累。第一阶段的结果表明，使用电动植物修复过程高达两个数量级更高的铅浓度可以实现在芥菜型油菜芥菜植物相比，传统的植物修复过程。第二阶段将侧重于优化和扩大的工艺参数，提高污染物提取的植物在施加电场的条件下。现场试验结果将产生技术和经济评估的过程和建议的适用性相结合的电动植物修复不同的化学和水文地质特征的污染场地。 电动植物修复技术将在重金属、放射性核素和有机污染物污染土壤的原位修复中具有广泛的应用前景。与传统的植物修复方法相比，该方法可以应用于污染物位于比植物根区更深的土壤。这将大大扩展植物修复的应用与深污染羽的网站。

This Small Business Innovation Research Phase II project describes the development of a new method for in situ removal of contaminants from soil by combining the processes of phytoremediation and electrokinetic remediation of soil. Phytoremediation is an attractive approach for cleanup of soil because it is a low cost and low maintenance technology, which can be applied in treatment of soils contaminated by heavy metals, radionuclides and organic contaminants. However, its application is limited to surface contamination only because the cleanup depth is strictly determined by the length of the plant roots. It is also a passive technology in terms of contaminant transport. The movement of contaminants in the soil is induced exclusively by a slow plant root suction, thus the efficiency of the contaminant removal depends on the extension of the plant roots in the soil subsurface. The new combined electrokinetic phytoremediation technology developed in Phase I utilizes the electrokinetic effects induced in soil by the application of an electric field to achieve an efficient transport of contaminants in the rhizosphere and to enhance metal accumulation in the plant roots. The Phase I results demonstrated that using the electrokinetic phytoremediation process up to two orders of magnitude higher lead concentration could be achieved in Brassica juncea mustard plants compared to the conventional phytoremediation process. Phase II will focus on the optimization and scaling-up of the process parameters governing the enhancement of contaminant extraction by the plants in conditions of the applied electric field. The field test results will yield technical and economical evaluation of the process and recommendations about applicability of the combined electrokinetic phytoremediation to contaminated sites with varying chemical and hydrogeological characteristics. The developed electrokinetic phytoremediation process will have large applications for in situ cleanup ofsoils contaminated by heavy metals, radionuclides, and/or organic contaminants. Compared to conventional phytoremediation processes, the proposed process can be applied to soils where contaminants are located deeper than the root zone of plant hyperaccumulators. This will significantly extend the application of phytoremediation to the sites with deep contaminant plumes.