The capacity of lignite coal ash to remove pollutants from leachate in landfill sites

摘要

Mam landfill sites in eastern Germany contain large amounts of lignite coal ash. Due to its chemical composition and high specific surface area as compared to other waste components, it can potentially remove large amounts of pollutants from leachate. To quantify its ability to do so for various types of pollutants, batch tests were conducted with a cation (Zn~(++)). an anion (NO_3~-) and an uncharged non-polar molecule (1,2-DCE, i.e. 1,2-Dichlorethane). Our results indicate that ash in landfills can retain large amounts of cations but only small amounts of anions and uncharged non-polar compounds. This is consistent with groundwater quality data from the vicinity of landfill sites in eastern Germany, where the concentrations of anions and uncharged non-polar substances are usually much higher downstream than upstream, while they are similar for heavy metals.