Análise econômica e ambiental da adoção de reatores UASB como alternativa de rota tecnológica para os futuros sistemas centralizados de Fortaleza, Ceará

Abstract

This paper aimed to assess the economic and environmental feasibilities of the scenario proposed in the Municipal Basic Sanitation Plan (MBSP) of Fortaleza, for the three sewage treatment plants (STP), and the alternative scenario replacing the aerobic technological routes with upflow anaerobic sludge blanket (UASB) reactors. Updated literature was consulted in order to gather information about electric consumption rates, as well as chemical oxygen demand (COD) and biogas production indexes. With regard to the alternative scenario, there was a carbon credit generation of 5,514.86 tonCO2eq·year-1 and a biogas production of 27.358,52 m³·day-1, equivalent to 73.7 MWh·day-1, which would be enough for supplying approximately 17,521 houses, equivalent to a serving rate of 1.55% in Fortaleza. The economic analysis of this alternative proposal returned capital expenditure (CAPEX) and operational expenditure (OPEX) values that provided a payback of about 29 years, differently from the calculated indices for the MBSP, once it was not noticed any energy positive credit for a potential financial return.