Energy use of biogas generated in a sewage treatment plant: potential to reduce eletricity costs and atmospheric emissions in northeast Brazil

Abstract

This research aimed to evaluate the management of a Sewage Treatment Plant (STP) and the existing biogas plant. A mathematical model was used to analyze the behavior of methane, biogas production and energy generation potential for a period of three years at the Jacuípe II Treatment Plant, located in northeastern Brazil. If the biogas plant were in operation, it would be possible to obtain autonomy for energy generation in the years 2016 and 2018. Greenhouse Gas Inventories - GHG, situational diagnosis of the biogas plant and scenario of financial losses with the deactivation of the plant were prepared. The results revealed that the emission of 1,958.38 tCH4 could have been avoided with the use of an energy generator (85% less than that emitted) or 1,151.99 tCH4 (50% less than emitted), if combustion by burner/flare. In addition, the financial loss due to the inactivity of the biogas plant resulted in US$ 154,162.38, about 67% of the actual energy expenditure of the plant in the period from 2016 to 2018. The reactivation of the biogas plant present in this station will bring environmental benefits, since the emission of GHG will be mitigated, in addition to financial benefits, since the energy use of biogas in the plant will provide a reduction in the expenses with electricity from STP Jacuípe II, in line with the aspects of sustainability.