Emission Control of Mercury from Stabilized and Solidified Products under Monofill Conditions

摘要

A column leaching test was conducted for 258 days to demonstrate Hg emissions in an engineered landfill where stabilized and solidified mercury by using sulfur and a binder such as cement was disposed of under monofill conditions with a granite soil layer. Thermodynamical analysis considering leachate quality showed that the mercury in the leachate could be chlorides, indicating that the mercury in metacinnabar in stabilized/solidified products (below, s/s products) dissolved in percolation water. However, the gaseous and liquid emissions of soluble mercury were extremely low because of adsorption in the granite soil. Nearly all mercury released from the stabilized/solidified product into the soil stayed within 1.5 cm of the product. Mercury contents were greater in deeper soil than in upper soil layers. It seems that migration of Hg out of the columns was delayed due to absorption of mercury in the soil and moisture. Sulfur polymer effectively immobilized mercury than low-alkali cement. However, both s/s products could achieve effective containment of mercury-containing waste under monofill conditions with a mercury-adsorbing soil layer. It is important not only to achieve stabilization/solidification of mercury but also to install a mercury-adsorption layer surrounding the treated waste to minimize mercury emissions from landfills.