零价铁PRB技术在地下水原位修复中的研究进展

PRB(可渗透反应墙)是地下水治理中新型的原位修复技术,具有成本低、处理效果好、对环境干扰小等优点,已逐渐应用到实际. 原位修复技术中PRB根据结构的不同可分为单处理系统PRB和多单元处理系统PRB,单处理系统PRB适用于单一污染物、污染浓度较低、污染羽规模较小的场地,多单元系统用于污染场地较复杂、污染种类较多的场地. 零价铁PRB去除地下水中无机污染物及有机组分的反应机理主要是氧化还原反应和还原性脱卤反应. 实际场地PRB的运行中存在的主要问题是零价铁钝化及PRB堵塞,现阶段的解决方法主要包括超声、电化学等,但为了提高PRB技术的实用性,铁材料的解钝化技术、实际场地PRB的设计与安装、PRB体系的长期运行及服务期满后的处置均需进一步的研究探索. 

Progress of Fe0-PRB in Remediation of Contaminated Groundwater

Permeable reactive barrier (PRB) is a new in situ remediation technology in the treatment of the groundwater. It has been gradually applied in practice due to its obvious advantages, such as low cost, high reactivity and small environmental interference effect. The structures of PRB were systematically introduced in this study. PRBs can be divided into single and multi-processing systems based on structures. The single processing system PRB included continuous trench PRB and funnel-gate PRB, and their configurations y were improved in some degree,such as Wall and curtain PRB、Injection PRB、GeoSiphon Cell、Slurry Wall-reaction vessel and so on. The single processing system PRB is suitable for a single pollutant with low concentration, and small-scale plume site. The multi-process system included series and parallel structures. The series structures exists trench box PRB and multi-continuous channel parallel PRB; Funnel and multi-channel、multi-funnel and multi-gate、multi-funnel and channel structures are common parallel structures. The multi-process system is suitable for the complex pollution site with kinds of pollutants. The mechanism of Fe0-PRB used to remove the inorganic and organic pollutants in groundwater was analyzed. The reaction mechanism mainly was a redox reaction and reducing dehalogenation reaction during the inorganic or organic pollutants removal in the groundwater. The study further pointed out that there were passivation and clogging problems during the Fe0-PRB used in actual operation, although there were some useful solutions to solve problems, such as ultrasonic, electrochemistry. In order to improve the practicability of PRB technology, the passivation removal of iron material, the design and installation of actual site, and the long-term operation and disposal after service expiry of PRB system should be focused on in the next study.