Influência da biodegradação no desenvolvimento de recalques em resíduos sólidos urbanos cobertos com uma cobertura intermediária de aterros sanitários

Influence of biodegradation on the development of settlements in municipal solid waste covered with an intermediate landfill cover

Abstract

Physico-chemical parameters of landfill leachate such as chemical oxygen demand (COD), electrical conductivity, pH, ions, etc. are useful for investigating the biodegradation phases of municipal solid waste (MSW) and can be determined through laboratory analysis. Given that biodegradation is responsible for a large part of the settlements that occur in MSW landfills, it is essential to monitor the biodegradation phases of the waste mass. These parameters do not behave individually, as they are interconnected. The use of lysimeters installed in the field, exposed to environmental conditions, makes it possible to simulate the degradation behavior of the waste mass. In this study, 3 lysimeters were built, containing MSW and covered by an intermediate cover layer from landfills in the state of Ceará, with different MSW compositions and surface drainage conditions (with and without leachate recirculation). In the lysimeter without recirculation, a decrease in COD was observed compared to the lysimeter with recirculated slurry. The recirculation of leachate contributed to greater settlements and to making the leachate more concentrated with salts such as chlorides, which directly influenced the increase in electrical conductivity.