Sulfur powder utilization and denitrification efficiency in an elemental sulfur-based membrane bioreactor with coagulant addition

The integration of elemental sulfur-based autotrophic denitrification with membrane bioreactor (MBR) technology offers a cost-effective solution for nitrate removal; however, stable operation demands efficient sulfur utilization and phosphorus management. This study explores sulfur consumption dynamics and the impacts of coagulant injection on denitrification efficiency. Sulfur consumption was closely correlated with nitrate removal rates, highlighting the critical role of stoichiometric sulfur availability for sustained denitrification. While coagulant addition enhanced phosphorus removal, excessive dosing impaired elemental sulfur-based microbial activity, reducing nitrate removal efficiency and increasing nitrite accumulation. Notably, microbial community analysis revealed a decline in the abundance of key sulfur-oxidizing bacteria, such as Sulfurimonas, under high coagulant concentrations. These findings emphasize the need for optimized sulfur and coagulant dosing strategies to balance phosphorus and nitrate removal while preserving microbial diversity and reactor stability. This study provides practical insights into operational parameters for efficient and sustainable ESAD-MBR processes.