Life cycle assessment of hydrogenotrophic denitrification in membrane aerated biofilm reactors for sustainable wastewater treatment

Abstract

The conventional anaerobic-anoxic-oxic (AAO) process for wastewater treatment is associated with high energy consumption and pollutant emissions due to its reliance on heterotrophic denitrification. In contrast, membrane aerated biofilm reactors (MABR) coupled with hydrogenotrophic denitrification (H<inf>2</inf>-MABR) offers a more promising alternative. This study conducts a life cycle assessment (LCA) to evaluate the environmental and economic benefits of H<inf>2</inf>-MABR compared to traditional AAO processes. Results indicate that even with a limited reactor life, the application of MABR in actual wastewater treatment plants can yield over 30 % reduction in environmental and economic impacts. Using CO<inf>2</inf> from biogas as a carbon source significantly reduces carbon emissions during the anaerobic stage, while the efficient nitrogen removal minimizes the need for wastewater recirculation and electricity consumption. The H<inf>2</inf>-driven denitrification process also avoids emissions and secondary pollution risks associated with organic electron donors. Furthermore, coupling H<inf>2</inf>-MABR with renewable energy source and Power-to-Gas technology further enhances sustainability by ensuring a stable hydrogen supply. Given the significant potential of H<inf>2</inf>-MABR for improving wastewater treatment, further research and large-scale implementation are highly encouraged.