Arsenic in Water: Removal Technolgoies and Residuals Disposal

砷是超级基金场地五种最常见的无机污染物之一。此外，供水商、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留物处理的影响，准备遵守饮用水中砷的新标准。因此，至关重要的是要有适当的处理方案，确定各种砷在水的条件和适当的方法来评估所造成的危害，不可避免地必须产生的含砷残留物。此外，如果含砷残留物被证明构成不可接受的风险，则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。如果后一种需要得不到解决，可以预见，处理后的残留物将成为未来超级基金清理的重点。该项目的重点是 在三个关键领域解决不足并取得进展：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与这些关键领域直接对齐。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对一种坚固、紧凑、经济和低维护的饮用水除砷技术的需求。第二个解决了从高浓度、复杂的含水基质如离子交换盐水和膜工艺浓缩物中选择性去除砷的技术需求。第二研究 研究领域涉及开发、机械解释和验证一项测试协议，以评估在填埋条件下从固体中沥滤出的砷和其他危险的含氧阴离子。将确定目前使用的协议的具体缺点，并将制定一个广泛适用的，非生物的协议，并测试的范围内的固体残留物，预计将产生的技术，从水中去除砷。最后的研究领域包括开发，机械解释和测试两种技术，以产生环境友好的砷处理残留物。一种封装技术的改进和测试，目前砷吸附技术的残留物，包括那些高盐含量的应用。作为补充，创新的结晶技术 将进行研究，并采取长期，高稳定性，接近最小体积的含砷铁污泥处置的概念证明。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工艺中产生。

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.