Interferências das condições ambientais e operacionais nas concentrações de biogás em biorreatores de bancada com resíduos sólidos.

Abstract

Environmental and operating conditions influence the behavior of microbial fermentation processes, interfering parameters, physical and physicochemical inherent in these processes. Studying these parameters separately and how they interact with each other, it is important, since these may improve performance of anaerobic bioreactors, thus raising the concentration of methane present in the biogas and also reduce the toxic substances released to the environment during the degradation process of waste. This work aimed to study the interference of environmental and operational conditions at concentrations of biogas from organic solid waste. Thus, two benchtop bioreactors were made on the premises of the Federal University of Campina Grande, with circular cross section in PVC tubes with dimensions of 0.90 m long and 0.2 m internal diameter, with a volume of 0,028 m3 (28L) . The experimental procedure used in this study consisted of the construction stages of benchtop bioreactors , instrumentation , testing, adjustment , volumetric and gravimetric composition of the waste , fillers and monitoring of parameters of temperature , moisture content , pH , total alkalinity , volatile acids , solid volatile ammonia , quantification of micro organisms (fungi and total aerobes), phytotoxicity tests and concentrations of gases (CO2, CH4 , O2 , CO and H2S ) performed by portable gas detector (Drager) . The results obtained in this study demonstrated that environmental and operational conditions imposed on anaerobic bioreactors for the treatment of organic waste are key to achieving high percentage of CH4 in biogas. The variations in temperatures, high humidity and observed throughout the process , caused a destabilization in the mass of waste , causing a buildup of acidic , negatively influencing the composition of the biogas , since the CH4 concentration was extremely low , while CO2 values recorded up to 90% . Environmental and operational conditions negatively influenced the concentrations of biogas, however provided a direction in relation to its monitoring and how they can be changed for the process to be optimized.