Development and Recycling of Novel Arsenic Removal Technology

As of 2006, the U.S. Environmental Protection Agency (EPA) changed the Maximum Contaminant Level (MCL) for arsenic from 50 parts per billion (ppb), to 10ppb because of links to cancer. Current remediation technologies are expensive; therefore, this change will result in increased economic pressure on rural communities with high levels of arsenic in their drinking water. Lowering of the standard has spurred the development of a novel remediation technology that has shown the ability to reduce arsenic in drinking water at the source, with the added benefit of low-cost disposal of a stable and benign waste product in ordinary landfills. Limestone-based materials appear to be an effective arsenic removal process that has great potential for source reduction in drinking water. A key requirement for any arsenic removal system is that the waste be disposed in a safe and cost effective manner. Phase one of this project focused on characterizing the long term stability of the arsenic iron-limestone waste product. The potential for the waste product to be disposed either in a normal landfill or recycled in cement is examined. Phase two of this research examined the potential use of pervious concrete as an in situ arsenic remediation system. This involved the designated construction of the Pervious Cement Reaction Barrier (PCRB). The research clearly showed that the PCRB has the potential to reduce arsenic in drinking water developed at the source. This is a significant expansion of the technical applications of the arsenic remediation technology. Toxicity Characteristic Leaching Protocol (TCLP) and California WET tests have indicated that the arsenic waste material is stable and can safely be disposed of in a landfill or incorporated into cement