Revisit the role of hydroxylamine in sulfur-driven autotrophic denitrification.

Through dedicated batch tests using the enriched sludge dominated by sulfur-oxidizing bacteria (SOB), the potential transformation of hydroxylamine (NHOH) by SOB and the effects of NHOH on the rate-limiting sequential reduction processes of sulfur-driven autotrophic denitrification (SDAD) were systematically explored in this study. The results indicated that NHOH might be first converted to NO by SOB and then participate in the SDAD process, thus accelerating the utilization of S and contributing to the formation of NO. Up to 3.