2012 NGWA Ground Water Summit: Innovate and Integrate

Natural Attenuation of Xenobiotic Organic Compounds in Landfill Leachate Plumes: Processes and Concepts

Monday, May 7, 2012: 3:10 p.m.
Terrace Room A-C (Hyatt Regency Orange County)
Poul L. Bjerg, Technical University of Denmark;
Nina Tuxen, Orbicon;
Lotte Ask Reitzel, University of Copenhagen;
Hans-Jørgen Albrechtsen, Technical University of Denmark;
Peter Kjeldsen, Technical University of Denmark;

Municipal landfills without liners or leachate collecting systems are numerous all over the world. Landfill sites may constitute a threat to downgradient ground water quality due to infiltration of leachate into the subsurface. This paper provides an overview of comprehensive field studies at three Danish landfill sites. The goal of the research activities is to provide a holistic description of attenuation processes for xenobiotic organic compounds in landfill leachate plumes. The approach used is cross disciplinary encompassing integration of field scale observations at different scales, field injection experiments, laboratory experiments and reactive solute transport modelling. This is illustrated in examples from the most recently investigated site - the Sjoelund Landfill. The research performed serve as good case studies to conceptualize natural attenuation processes in landfill leachate plumes and also support the notion that monitored natural attenuation (MNA) may be a possible remediation strategy at landfills. However, landfill leachate plumes challenge traditional approaches and tools used in the application of MNA. In particular, the use of in situ indicators to document mass removal in landfill leachate plumes is emphasized. In this paper we advocate the application of conceptual and numerical models as tools for the integration of data and testing of hypotheses. In addition to the overview, the presentation will discuss an on-going investigation at a Danish landfill in a clayey till setting located close to a local stream. The results highlight that landfill studies in complex geological media and leaching of landfill leachate pollutants into surface water deserve more attention.