铬污染场地原位修复技术应用现状与展望

Status and prospect of in-situ remediation technologies applied in hexavalent chromium contaminated sites

  • 摘要: 六价铬Cr(Ⅵ)是一种来源广泛的重金属污染物,因其形态、价态多样,地球化学反应过程极其复杂,同时国内Cr(Ⅵ)污染场地众多,对其修复具有很大的挑战性。原位修复因不开挖土方、对环境干扰小等诸多优势逐渐成为污染场地修复策略的主流。综述了国内外Cr(Ⅵ)不同类型原位修复技术研究进展,在结合大量原位修复工程案例的基础上重点分析了原位生物、原位化学修复技术与不同注入方式的应用效果。阐明了不同类型原位修复技术的适用地层条件、适用浓度范围、影响半径、修复工期、修复介质、药剂类型及用量与施加方式等关键参数。针对复杂的Cr(Ⅵ)污染场地,建立精准的污染场地概念模型,选取高效适宜的修复药剂和注入方式或者修复工艺组合,是确保修复效果的关键。通过分析现有Cr(Ⅵ)不同原位修复技术在实际应用中的优缺点,探索其在不同场景的适用性,同时对技术发展方向进行了展望。

     

    Abstract: Hexavalent chromium Cr(Ⅵ) is a typical heavy metal pollutant with a wide range of sources. Due to its diverse forms and valence states, the geo-chemical reaction process is extremely complicated. There are lots of Cr(Ⅵ) contaminated plots in China and the remediation of Cr(Ⅵ) contaminated sites is very challenging. In-situ remediation has gradually become the mainstream of remediation strategies for contaminated sites due to many advantages such as no excavation and less environmental interference. The latest research progress of different in-situ remediation technologies for Cr(Ⅵ) was reviewed. Based on a large number of in-situ remediation engineering cases at home and abroad, the application effects of in-situ biological, in-situ chemical and other remediation technologies and different injection methods were analyzed. The key parameters of different types of in-situ remediation technologies including applicable geological conditions, applicable concentration range, influence radius, remediation duration, remediation medium, agent type and dosage, and injection method were clarified. It played a key role to establish a precise contamination field concept model, and choose efficient chemicals and the best injection method or remediation process combinations for complex contaminated sites. The advantages and disadvantages of different in-situ remediation technologies of Cr(Ⅵ) were compared in examples, and their different applicable scenarios were explored. At the same time, the future development direction of technologies was prospected.

     

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