Desenvolvimento de metodologia para seleção de áreas adequadas e projeto básico de aterro sanitário para o município de Bento Gonçalves – RS

Abstract

When disposed inappropriately, solid waste is considered one of the main causes of negative environmental impacts, affecting the public health of the population and the environment. Sanitary landfill can be defined as an adequate final disposal of municipal solid waste (MSW), since it is based on engineering criteria. Thus, this final paper aimed to develop a landfill project for the municipality of Bento Gonçalves ? RS as an alternative technological route for the treatment and final disposal of MSW. The characterization of the RSU in the current management model was performed, as well as the projection of their generation over a 20-year horizon, and it was found that, in 2042, the population will be 156,545 inhabitants who will dispose of about 116.33 tons of waste per day to the landfill. A methodology based on eight steps was developed to define the most suitable location for the installation of the project: estimating the required area; determining the set of selection criteria; setting priorities for meeting the settled criteria; analysis with Geographic Information Systems tool; getting information about potential areas; critical analysis of each area; and verifying with the municipality and defining the landfill implementation area. Only one among the four potential areas was not considered "Unacceptable", which enabled the installation of the landfill requiring a total area of 8.34 hectares. After choosing it, a physical, biotic and socioeconomic diagnosis was carried out to prove that the defined location was suitable to receive the project. Then, the technical project was elaborated with three sectors for waste disposal and a support one. The MSW sectors were divided into ten cells that will be formed in four stages with 5.5 m each, 35° internal slope inclination and berms with 2.5 m in width. Waste will be spread by a crawler tractor with inclination 1(V):3(H) and compacted with a sheep foot roller with at least 6 passes. The project will also feature: base waterproofing system composed of clay and HDPE geomembrane; leachate drainage system formed by perforated corrugated HDPE pipes DN 65 mm and DN 80 mm wrapped in a drainage layer of gravel no. 2 protected by non-woven geotextile; gas drainage system with a 1500 mm total diameter, composed of a perforated reinforced DN 700 mm concrete tube, enclosed by gravel no. 4 and limited by a metallic mesh; leachate treatment system, consisting of a 2 mm mesh sieve, a 46 m diameter facultative lagoon and secondary treatment by electrolysis; gas treatment system through burners (flares); daily and intermediate coverage system carried out by reusing clayey soil removed during land preparation; final coverage composed of a layer of compacted clay, organic soil and grass planting; rainwater drainage system formed by DN 500 and 600 mm concrete gutters; and a buried HDPE pipe system with DN 110, 500, 600 and 800 mm double walls, so that the treated effluent and drained rainwater are sent to the nearest water resource. During the installation and after the closure of the landfill, maintenance and monitoring procedures were planned to ensure its full functioning and stability. The total estimated value for the installation of the project was 59.3 million with a payback time of between 9 and 10 years, making it economically viable. It was also found that the installation of the landfill is technically and environmentally feasible, within the established project conditions. [resumo fornecido pelo autor]