Arsenic in Water: Removal Technolgoies and Residuals Disposal

砷是超级基金所在地最常见的五种无机污染物之一。此外，水供应商、固体废物处理实体和监管机构正在通过评估除砷方案和残渣处理的影响，准备遵守饮用水中砷的新标准。因此，至关重要的是为水条件中的各种砷确定适当的处理方案，并制定适当的方法来评估不可避免地必须产生的含砷残留物所构成的危险。此外，在含砷残留物被证明构成不可接受的风险的程度上，必须开发技术来稳定这些残留物，并将风险降低到可接受的水平。如果后一种需求得不到解决，可以预见的是，被处置的剩余资金将成为未来超级基金清理的重点。这个项目的重点是 解决不足并在三个关键领域取得进展：处理技术、残留物评估和残留物稳定化。独立但相互依存的研究领域直接与这些关键领域保持一致。第一个研究领域涉及开发和测试两种从水中去除砷的创新方法。一种方法旨在满足小型公用事业公司从饮用水中去除砷的强大、紧凑、经济和低维护技术的需求。第二个问题是需要一种从离子交换盐水和膜工艺浓缩液等高浓度、复杂的水基质中选择性去除砷的技术。第二项研究 研究领域包括开发、机械解释和验证测试方案，以评估在垃圾填埋场条件下从固体中浸出的砷和其他有害氧离子。将找出目前使用的方案的具体缺点，并将制定一项广泛适用的非生物方案，并针对预计将由水中除砷技术产生的各种固体残留物进行测试。最后的研究领域涉及两种生产环境无害的砷处理残留物的技术的开发、机理解释和测试。改进了一种封装技术，并将其应用于现有砷吸附技术的残留物上，包括高含盐量的砷吸附技术。在相辅相成的努力中，一种创新的结晶技术 将对长期、高稳定性、接近最小容量的含砷铁泥的处置进行研究并进行概念验证。这些污泥将是本项目开发的创新去除技术产生的残留物，并可能在离子交换和膜过程中产生。

Arsenic is one of the five most common inorganic contaminants at Superfund sites. In addition, water providers, solid waste disposal entities, and regulatory agencies are gearing up to comply with a new standard for arsenic in drinking water, by evaluating arsenic removal options and the implications of residuals disposal. Consequently, it is critical to have appropriate treatment options identified for a variety of arsenic in water conditions and appropriate methods developed for assessing the hazard posed by the arsenic-bearing residuals that inevitably must be produced. Furthermore, to the degree that arsenic-bearing residuals are shown to pose an unacceptable risk, technologies must be developed to stabilize these residuals and mitigate the risk to an acceptable level. If this latter need is left unaddressed, it is foreseeable the disposed residuals will become the focus of future Superfund clean-ups. This project focuses on addressing shortcomings and providing advances in three critical areas: treatment technologies, residuals assessment and residuals stabilization. Separate, yet interdependent research study areas are directly aligned with these critical areas. The first study area involves development and testing of two innovative approaches for removing arsenic from water. One approach aims at meeting the need for a robust, compact, economical and low maintenance technology for arsenic removal from drinking water by small utilities. The second addresses the need for a technology for selective arsenic removal from high concentration, complex aqueous matrices such as ion exchange brines and membrane process concentrates. The second research study area involves development, mechanistic interpretation and validation of a testing protocol to assess arsenic and other hazardous oxyanion leaching from solids under landfill conditions. Specific shortcomings of currently used protocols will be identified and a widely applicable, abiotic protocol will be developed and tested for the range of solid residuals that are expected to be generated by technologies for removing arsenic from water. The final research study area involves development, mechanistic interpretation and testing of two technologies to produce environmentally benign arsenic treatment residuals. An encapsulation technology is refined and tested for application on residuals of current arsenic adsorption technologies, including those with high salt contents. In a complementary effort, an innovative crystallization technology will be studied and taken to proof of concept for long-term, high stability, near-minimum volume disposal of arsenic-laden iron sludges. These sludges will be the residuals generated from the innovative removal technologies developed in this project and potentially generated in ion exchange and membrane processes.