Avaliação da eficiência do método Fukuoka implementado na Lixeira municipal de Hulene na retenção dos agentes poluentes das águas subterrâneas

Abstract

The Fukuka method is a semi-aerobic landfill management technology developed in the Japanese municipality of Fukuoka. This technology allows for the construction of improved landfills in a simple and low-cost manner, using materials and methods available at the site to be implemented. A semi-aerobic landfill contains areas with aerobic biochemical environments with the introduction of air from the gas ventilation tubes and areas with anaerobic biochemical environments. The implementation of this method in the Hulene municipal landfill is mainly due to the optimization and increase in the useful life of the landfill and the minimization of the environmental and socio-environmental impact within the landfill and in the Hulene B and Laulane neighborhoods, through the rapid stabilization of the biodegradation process of urban solid waste with the recirculation of the leachate to the collection basin. For this study, three leachate samples were collected and coded as P1, P2 and P3. Sample P1 was collected in the leachate collection basin; sample P2 was collected in the lowest elevation region and sample P3 was collected inside the landfill in the solid waste layers. These samples were subjected to analyses of their microbiological, biochemical, physicochemical and chemical properties. The daily flow rate of leachate recirculated to the collection basins was subsequently calculated and the concentrations of biogas emitted by the landfill were quantified. The results show that the leachate consists of pathogenic microorganisms that the Fukuoka method cannot eliminate; nitrates, sulphides and heavy metals that constitute its toxic load in lower concentrations, indicating that the method is effective in reducing these toxic pollutants. The water that occurs in the lower elevations is actually contaminated by the leachate and reaches the groundwater. The contamination plume disappears at 200 m. Approximately 2,678 m3/day of leachate is diverted from the urban solid waste layer during the peak of the dry season to the collection basin. This volume increases with the onset of the rainy season. The reduction in the volume of leachate and the concentration of contaminants, as well as the difference in the emission of gases such as methane and carbon dioxide, indicate that the Fukuoka method is working well.(TRADUÇAO NOSSA)