Project

Contaminant concentrations in landfill pore water: changes during stimulated degradation

Landfills pose a large threat to the human health & environment (HHE), both through gaseous emissions and through the release of contaminant-rich leachate to the underlying soil.

Background

Traditionally landfills are sealed to restrict these emissions, yet this is a costly endeavour: the waste remains unchanged and thus seals need to be replaced and leachate needs to be monitored and treated indefinitely. An alternative approach is to instead treat landfills as bioreactors, stimulating biodegradation through flushing and aeration and thereby ultimately reducing their emissions until they are no longer a threat to the HHE. The effects of this ‘active treatment’ are currently being investigated on a landfill scale at three different locations in the Netherlands.

As part of this research, two ‘sleeves’ have been installed at one of the research landfills. These sleeves contain 20 ceramic cups at different depths, which can directly sample the surrounding pore water. Thus, a clear vertical distribution of contaminants and other (chemical)parameters can be determined. This provides insights both in the vertical heterogeneity within the landfill, but also on contaminant association and the influence of different environmental parameters (pH, organic matter) on contaminant availability. Already three sampling sessions have been conducted, providing the first insights on these mechanisms.

The aim of this thesis is further explore how contaminant concentrations and environmental parameters change with depth, and in how far this is affected by the ‘active treatment’ of the landfill. This will be done by doing additional samplings of the sleeves, analysing the thus acquired data set, and potentially using geochemical modelling to further understand the processes of main relevance.

Used skills

  • Pore water sampling;
  • Laboratory work;
  • Geochemical modelling;
  • Data processing;

Requirements

  • Soil Chemistry and Chemical Soil Quality (SOC81336)