Characteristics of Cr(VI) from Recycled Material by dry-wet repetition test

Abstract

In Japan, There is Law on Promoting Green procurement Purchasing and recycled materials are authorized for construction materials. In local division, there are many authorized systems for recycled material by local governments. There is no regulation for environmental impact to use recycled material for construction and usually we use judgment methods for contaminated soil (Leaching test: Japan Legal leaching Test (JLT46)). In soil environmental standards, there are 2 methods for judgment. These are leaching test (JLT46) and soil extraction test (JLT19). Soil and alternative material are similar at physical characteristics but are different at chemical characteristics. In this research, we try to test the recycled fill up material made from inorganic sludge. Recently we find that this materials release Cr(VI) and start to recovery from used site. We investigated characteristics of this material and mechanism of leaching Cr(VI) in site. In our experiment, we tried characterization tests and Dry-Wet repetition test (Environmental exposure test). This materials include much T-Cr and a part of Cr existed as Cr(VI). Cr(VI) concentration was increased by dry wet repetition. Characteristics of leaching Cr(VI) were influenced by pH.