ABSTRACT
Landfill natural attenuation may be a viable risk-based corrective action for old, un-lined landfills. An Integrated Landfill Modeling System (ILMS) has been developed to assist in the engineering of landfill remedies that incorporate natural attenuation. The ILMS integrates the simulation results from four different models: 1. the HELP model for predicting the hydrologic performance of various landfill cap configurations; 2. a leachate composition model (LEACHATE) for predicting long-term trends in leachate constituent concentrations; 3. a three-dimensional groundwater flow model (MODFLOW) for simulating migration pathways in aquifers situated below unlined landfills; and, 4. a three-dimensional groundwater reactive transport model (BioRedox) that simulates coupled oxidation-reduction reactions for predicting the extent and sequence of redox zones which develop downgradient from unlined landfills.
