Potencial de recuperação energética do biogás gerado em aterros sanitários de pequeno e médio porte na região Oeste do Paraná

Abstract

The management of municipal solid waste (MSW) has become a challenging task for municipalities due to exponential population growth and economic development. In Brazil, the final disposal in landfills is usually applied, generating gaseous and liquid pollutants by the degradation of the organic fraction of MSW. On the other hand, this organic fraction represents a biomass with potential for energy use through the production of biogas generated by the degradation of organic matter in landfills. With this, this study aimed to realize different scenarios with municipalities at a distance of up to 70 km from Medianeira - PR (host site) in order to evaluate the theoretical potential of biogas and the feasibility of implementing an energy recovery project. The methodology is based on calculations for projection of population growth and MSW and use of the LandGEM software developed by the U.S. Environmental Protection Agency's (EPA) to estimate the theoretical potential of biogas during the 20 year lifetime of the landfill. In addition, calculations were performed to convert the gas to energy and to estimate the financial resource of the project. Scenario 1, composed only of Medianeira, obtained a maximum production of 2,818,489 m3 of biogas in 2043, the year following the closure of the landfill. Scenario 2, on the other hand, composed of Medianeira and municipalities at a distance of 20 km from the research site, obtained 5,973,239 m3 of biogas in the same year. As for scenario 3 and 4, formed by municipalities at distances of 40 and 70 km, respectively, they presented a maximum volume of 9,494,077 and 12,174,222 m3 of biogas in the same order. The accumulated volume of CH4 in scenario 1 was 1,409,245 m3, while scenario 2 had 2,687,958 m3 of CH4. Scenarios 3 and 4 had maximum methane accumulated volumes of 4,272,335 and 5,478,400 m3. As for the energy generated, scenario 1 has the potential to supply 252 inhabitants in the year of maximum production, which is equivalent to 2.322 MWh and generates a maximum financial resource of R$ 1,5 mi. Scenario 2 supplies up to 6,203 inhabitants with 4,429 MWh, which corresponds to a financial resource of R$ 3.2 mi. Scenario 3 reaches an energy potential of 7,039 MWh and supplies up to 9,859 inhabitants, corresponding to a financial resource of R$ 5.1 million. The fourth and last scenario with an energy potential of 9,027 MWh supplies up to 12,642 inhabitants and has a financial resource of R$ 6.7 million. Thus, it is concluded that the scenario 2 is the most economically feasible, because it generates energy return twice as much as the city of Medianeira- PR including cities that are closer to the headquarters location. Finally, technical, economic and environmental feasibility studies (EVTEA) can be conducted in order to predict the costs and benefits of implementing a gas capture system in a shared landfill based on scenario 2.