Landfill leachate is a liquid that is mainly produced by the rain which falls on the solid waste. The leachate usually contains high concentrations of ammonium, organic matter, toxic compounds and heavy metals. This master thesis introduces briefly facts of landfills, leachate formation and leachate characteristics. The formation of leachate threatens the groundwater, soil and environment. For this reason, treatment methods to remove ammonium need to be explored. To treat landfill leachate, an option is to send leachate to a wastewater treatment plant nearby. However, after the sludge certification system REVAQ has been implemented for increasing the quality of sludge,
leachate in Sweden should be treated on-site instead of being treated in the municipal wastewater treatment plants. In this thesis, more than twenty leachate treatment methods are presented including physical/chemical methods and biological methods. Two landfills will be introduced in this thesis, Hedeskoga and Måsalycke landfills, both located in Southern Sweden. Treatment methods and performances will be introduced. The treated leachate of the two landfills contains comparatively high concentrations of ammonium.
To determine the toxicity of the two landfills, an inhibition test of nitrification was done. Four kinds of leachate were tested from the two landfills, dilution of 50%, 20%, 10% and 5% of each leachate was tested with the inhibition ranging from 30% to -19%. Therefore, the reasons for the high ammonium concentration in Hedeskoga landfill may be due to the toxic problems and cold weather. In order to reduce the high concentration of ammonium, different
leachate treatment methods were evaluated, rotating biological contractor, activated sludge, trickling filters, biological aerated filters, moving bed biofilm reactors and sequencing batch reactors are recommended for the two landfills in order to reduce the concentration of ammonium.