A comparative study of the leachates produced by anaerobic digestion in a pilot plant and at a sanitary landfill in Asturias, Spain

Leachates produced in a simulated landfill pilot plant were compared with those produced at the Zoreda landfill in asturias, Spain. Three loads of different amounts of municipal solid waste (MSW) were added to the Filer plant at different stages, thus forming consecutive layers. Up to the present, approximately 3 333 000 t (metric tons) of MSW have been deposited in the landfill in 2.5 m high layers which are covered with soil from the surrounding area. The organic load of the leachates as COD decreased with time in both systems from very high initial values to relatively low ones by the end of the study, although they were higher in the actual landfill (approximately 4g as opposed to 1.5 g O-2 dm(-3) in the pilot plant). The pH decreased initially to values close to 6, but then increased to around 8. Ammoniacal-N (ammoniacal nitrogen) concentrations were high in both systems whereas metal concentrations were low.