MINIMUM LEACHATE RECIRCULATION RATES FOR AEROBIC AND ANAEROBIC DEGRADATION IN PILOT SCALE WASTE LANDFILL CELLS

摘要

A substantial number of landfills in Southeastern Argentina evidence dryness within the waste mass that militates against the rapid degradation of their organic fraction (Reyes et al, 2007). It has often been argued that annual rainfall is the origin of this lack of moisture content. However, while annual rain records indicate deficient (negative) water balances at several Patagonian cities (with evapotranspiration often twice infiltration), it is the rainfall concentration that matters. Storm events do not provide regular water infiltration. Yet, the fact that the waste mass at these landfills is not subjected to large water infiltration volumes (except during storm events) remains an advantage because their bottom drainage systems consist almost always of French drains incapable of preventing leachate build up. Finding a threshold value of moisture content at which degradation rates increase and French drains remain operative will help in shortening the contaminant lifespan of the facilities while avoiding the risk of overtopping or "bathtubbing".