Effect of recirculation of treaty leachate in landfill behavior

Abstract

In Latin America, urban solid wastes (USW) are mostly disposed in sanitary landfills that have the disadvantage of slow organic matter stabilization. The behavior of two sanitary landfills was monitored in a pre-pilot scale with the purpose of evaluating the effect of the recirculation of anaerobically treated leachate on their velocities of settlement. Both landfills were initially loaded with 0.5 tons of USW, one operating with a recirculation of leachate treated in an anaerobic filter and the other with a recirculation of untreated leachate, with estimated stabilization times of 3.7 and 13.3 years, respectively. Considering the good results obtained in the pre-pilot scale with the recirculation of treated leachate, this same study was conducted in a pilot scale in a sanitary landfill initially loaded with 1,440 tons of USW. It was found that the average velocity of settlement doubles during the periods of recirculation of the treated leachate in relation to the landfills in which there is no recirculation of leachate. It can be concluded that it is possible to reduce the stabilization time by approximately 40% if untreated leachate is recirculated and by approximately 80% if this leachate is first anaerobically treated.