Leaching test using samples from a modern, carbon-poor landfill

Landfilling of organic waste is prohibited in Sweden. Modern Swedish landfills differ from landfills containing municipal solid waste rich in organic matter. As a first step to understanding long-term leaching from modern landfills, a leaching test was performed. The leaching of heavy metals was small compared to the total contents. At a liquid to solid ratio of 10 more than 99 % of most heavy metals remained in the waste. The degradation potential measured as respiration during four days was below 1 mg O2•g-1 dry waste and it decreased during the leaching. Due to the low degradability of this waste it does not seem motivated to keep the landfill moist to enhance degradation during the active phase. The contaminants of concern in a modern landfill are largely non-degradable, e.g. heavy metals, and they must be disposed of somewhere once removed from the leachate. A reasonable management option, therefore, could be to keep the landfill as dry as possible in an attempt to keep the metals in the landfill for as long time as possible.