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 t hose produced at the Zoreda landfill in asturias, Spain. Three loads of dif ferent amounts of municipal solid waste (MSW) were added to the Filer plant at different stages, thus forming consecutive layers. Up to the present, a pproximately 3 333 000 t (metric tons) of MSW have been deposited in the la ndfill in 2.5 m high layers which are covered with soil from the surroundin g area. The organic load of the leachates as COD decreased with time in bot h systems from very high initial values to relatively low ones by the end o f the study, although they were higher in the actual landfill (approximatel y 4g as opposed to 1.5 g O-2 dm(-3) in the pilot plant). The pH decreased i nitially to values close to 6, but then increased to around 8. Ammoniacal-N (ammoniacal nitrogen) concentrations were high in both systems whereas met al concentrations were low.