Análise integrada da tecnologia microaeróbia como estratégia de dessulfurização In-Situ

Abstract

Several studies, mainly related to the anaerobic digestion of solid wastes and sewage with high sulfate concentration, describe the advantages of the microareasure both for the treatment of the biogas and for the improvement of the efficiency of the system as a whole. However, a better understanding of the process is required for low sulphate sewage, as in the case of sanitary sewage, as well as a deeper understanding of the engineering aspects, both in the design of the system and in the operational aspects. In this sense, the best location for atmospheric air dosing or use of pure oxygen, flow rate to be applied, diffusion devices for microaeration, process control, evaluation of the system when subjected to shocks and interruption of aeration etc. can be cited. , As well as aspects related to microbial participation and economic and life cycle studies. The objective of the present study was to conduct an integrated analysis of microaerobic technology as an in-situ desulphurisation strategy for effluents with low sulphate concentration. To do so, the engineering aspects were evaluated, such as the best microaeration flow and best application point, as well as the quality of the biogas generated with the in-situ technology, compared to the ex-situ technology of chemical absorption with hydroxide Sodium, being in this the biogas generated during the operation of an anaerobic reactor. In all periods of study, the microbial population dynamics of the Bacteria and Archaea domains were evaluated by means of molecular techniques such as PCR / DGGE. Finally, an economic analysis and a life cycle assessment (LCA) of the microaeration were carried out in relation to the chemical absorption. Experiments were conducted in parallel with two continuous flow reactors: R1 (Alkaline with alkaline absorption of the generated biogas) and R2 (microaerobic), in order to compare the desulfurization efficiency of the biogas by the different technologies studied. The reactors were fed with synthetic effluent and microaeration that consisted of the injection of atmospheric air, initially in the headspace, but which extended to other points in the sludge blanket of the reactor. In general, the microaerobic system has proved to be very attractive in all engineering, economic and life cycle aspects evaluated, as well as operational stability, and can be considered as an effective technique for in situ effluent desulphurisation With low sulphate concentration.