Mercury emission from sulfide/solidified mercury waste in a simulated landfill lysimeters

Wastes containing mercury or mercury compounds are designated as "industrial waste requiring special management" owing to their toxicity. They must be stabilized to HgS by sulfurization using a ball mill before landfill disposal to prevent mercury dissolution and diffusion. Recently, methods for treating and disposing of mercury waste have been investigated. The current study aimed to confirm the safety of sulfurized/solidified mercury; therefore, two additional types of solidification are adopted: cement solidification and epoxy resin solidification. Further, the existing sulfur solidification method was also modified. The results obtained by the lysimeter test are as follows: The mercury concentration in leachate satisfied the effluent standard from the initial and met the environmental standard after 4 months. There was no difference in the mercury diffusion amount between the lysimeters with sulfurized/solidified mercury and blank. The maximum mercury elution ratio from the lysimeters was 0.00002%, indicating that there is no risk of mercury elution from sulfurized/solidified mercury in landfills of incineration residue and mixed waste. The new solidification methods, low alkali cement solidification and epoxy resin solidification, have a low risk of mercury diffusion. The safety of sulfurized/solidified mercury waste using low alkali cement or epoxy resin instead of modified sulfur solidification in a real landfill site was confirmed.