Defensa de tesis doctoral Electrochemical control and minimization of hydrogen sulfide formation in anaerobic systems
A cargo de: Natalia Sergienko
Directores: Dra. Jelena Radjenovic i Dr. Oriol Gutierrez
Formation of hydrogen sulfide represents a major challenge in the operation of wastewater collection systems. Hydrogen sulfide is malodourous and toxic gas, which causes corrosion of pipes, wells, and constructions, hence damaging the structural integrity of the collection systems and significantly reducing their lifetime. Control of hydrogen sulfide formation, accumulation and emission is normally handled by the dosing of chemicals to the waste stream, which leads to considerable operating costs and risks associated with the transport, storage and handling of chemicals.
Electrochemical treatment is an attractive alternative to the existing technologies for sulfide control, as it offers a robust removal of sulfide in situ and avoids the costs and risks related to chemical usage. However, its implementation on practice in often limited due to important drawbacks such as lack of efficient, selective and low-cost anode material and electrode passivation with elemental sulfur, the final product of the electrochemical sulfide oxidation. Therefore, the main objective of the present thesis was to address these limitations and to propose an electrochemical treatment system that would be capable of robust long-term sulfide oxidation. For this purpose, the performance low-cost carbon-based felts applied for sulfide oxidation was evaluated. Furthermore, novel electrode materials such as
graphite felt coated with catalytically active MnO2 or Ti plate with TiO2 nanotube array interlayer coated with MnO2 were developed and applied for sulfide oxidation. Finally, the problem of sulfur passivation was also addressed by testing different regeneration strategies and approaches.
Considering the small footprint, low-cost, stability, high efficiency and selectivity, the electrochemical treatment system developed in this study can potentially evolve into an important desulfurization technology for sewage or other types of waste streams.