Landfill Simulation Reactors – a Method to Predict the Behaviour of Field-scale Landfills?

SUMMARY: Investigations into landfill simulation reactors and a full scale landfills are used for predicting emissions from municipal solid waste landfills. In the present study the water flow and solute transport through a landfill simulation reactor and a full scale landfill (using the same waste) has been investigated. The results indicate that, due to preferential flow pathways the water flow in field-scale landfills is less uniform than in laboratory experiments. Based on tracer experiments, it can be discerned that in laboratory-scale experiments around 40% of pore water participates in solute transport, whereas this fraction amounts to less than 0.2% in the investigated full-scale landfill. Main consequences of the difference in water flow and thus solute transport are: (a) leachate emissions from full-scale landfills decrease faster than predicted by laboratory experiments, and (b) the stock of materials remaining in the landfill body, and thus the long-term emission potential, is likely to be underestimated by laboratory landfill simulations.