Emissions of SOx and NOx from flue gases require treatment before release into the atmosphere according to the current legislation. Physical-chemical treatments used so far are expensive and generate effluents that require further processing. This project faces the challenge of developing a comprehensive treatment process for SOx and NOx from flue gases by economical, robust and environmentally friendly biological methods that also take into account the reuse of energy and resources in process development as well as residues valorization. The proposed process is based on a multistage process including selective absorption of SOx and Nox and biological reduction-oxidation processes based on sulfate-reducing microorganisms (SRB) and sulfide-oxidizing microorganisms (SOB) that allow the recovery of elemental sulfur.
To demonstrate the feasibility of the process, the project will carry out the different stages of the whole system at laboratory scale in order to characterize the maximum capabilities of each of the stages and get valuable design data for different operating scenarios. The characterization of the process steps will be complemented with the use of modeling techniques using computational fluid-dynamics, respirometric techniques to determine the activity of SRB and SOB biomass, and the development of techniques for analytes monitoring. Monitoring will be applied to both, the operation of the bioreactors through the development of microfluidic systems, and the biofilm development using microelectrodes based on microelectronic technology. Finally, the data obtained from the project will allow to create a guide of the best available techniques for a broad range of typical compositions of SOx and NOx emissions from flue gases.
Project objectives achievement involves a new paradigm in the field of treatment of gaseous effluents. Specifically, it aims to provide a new approach to the problems of flue gases, changing the concept we have today that they are harmful and useless residue to address as a potential valuable effluent. The solution provided by this project involves i) to obtain a product with an interesting economic value (130€/ ton), ii) a low consumption of chemical reagents by maximizing the reutilization of effluents from the different stages, iii) to dispose effluents hardly recoverable, and iv) to reduce treatment costs.