ASSESSMENT OF ECOTITE~(TM) FOR USE IN ACID ROCK DRAINAGE TREATMENT

摘要

Limestone or limestone-based products are often the materials of choice for passively treating acid rock drainage (ARD) when site and discharge characteristics are favorable. However, limestone treatment may require long detention times, large quantities of material, and significant land area for implementation. This condition may result in limited applicability due to the size of treatment areas needed for limestone contact and capture of metal precipitates. In addition, use of limestone materials for passive treatment may be limited by discharge characteristics of the ARD such as high metals and acidity concentrations. ECOTITE~(TM) is a material composed of approximately one-third iron by weight including the minerals ackermanite, magnetite, hematite, goethite, monoxides (e.g., wustite), metallic iron, and iron sulfides. ECOTITE~(TM) has demonstrated an ability to generate alkalinity through dissolution of calcium-silicate minerals with relatively short contact times. In addition, ferric oxides within ECOTITE~(TM) provide adsorption capacity for metal retention. Laboratory and on-site bench scale tests have been conducted to evaluate ECOTITE~(TM) materials for ARD treatment, particularly at sites where conventional passive treatment techniques posed significant challenges. ECOTITE~(TM) -based treatment has been tested successfully on a variety of discharge water characteristics. Use of ECOTITE~(TM) -based treatment technology may broaden the range of ARD water quality characteristics and flow rates able to be passively treated.