Caracterização do potencial energético e estudo físico-químico do lodo da Estação de Tratamento de Esgoto do DMAE - Uberlânida-MG

Abstract

The calorific value of sewage sludge produced in treatment plant STP Uberabinha was determined in this work, in order to evaluate its potential energy and thus point the possibility of using this biomass as fuel, plus the fact of this use contribute to solution the problem of disposal of this solid in the environment. Obtained by anaerobic digestion, followed by dewatering in centrifugal this material are destined for the municipal landifill of the city of Uberlândia-MG. As the quantities of sludge generated have been increasing in recent years, the physical chemical characterization of this waste is the first step for its energy use, leading to an environmentally conscious management. Thus thermal analysis, including thermogravimetry (TG), differential thermal analysis (DTA) and differential scanning calorimeter (DSC) in nitrogen atmosphere, analysis of the content of carbon, beyond Fourier transform infrared spectroscopy (FTIR) of the sludge, to knowledge of the main groups organic and inorganic present in material, were performed. The experimental results indicated a accentuated exotherm in the DTA curve around 450°C, characteristic of the decomposition of carbon refractory, and enthalpy content 2,4 time that of the first exotherm located at 302°C. Calorimeter analysis revealed a higher calorific value of anaerobically digested sludge equal to 16,2 MJ.kg-1 which compares favorably with values previously reported in the literature for other sludge generated in sewage treatment plants sewage domestic. In addition, the calorific value for this sludge proved to be of the same order of magnitude of the energy potential of biomass as wet wood or even superior to other biomass used for energy generation such as sugar cane bagasse into briquette, with the possibility better performance when its use as fuel. This residue also presented relationship volatile solids /total solids (VS/TS) 65%, and almost entirely in front of the total organic carbon content of total carbon, contributing positively to the energy use of its combustion.