Cultivation of the coupling bacteria for simultaneous autotrophic nitrogen and sulfur removal and its remediation effect on the river sediment

Abstract

The coupling bacteria for simultaneous autotrophic nitrogen and sulfur removal was cultivated by supplying sulfide to an Anammox biofilter treating low-strength wastewater. The results showed that sulfide-driven autotrophic denitrification (SAD) was successfully induced, and the total nitrogen (TN) removal increased from 83.0% to 94.4% when the sulfide concentration was increased to 25 mg L−1, with complete sulfide removal. Mass balance analysis suggested that 30.5% of the generated nitrate was reduced to nitrite while the rest was converted to nitrogen gas. The relative abundance of Anammox bacteria (Candidatus Kuenenia) increased from 9.16% to 18.8%, and the SAD bacteria (Thiobacillus) increased from 0.07% to 2.00%, both contributing collaboratively to nitrogen and sulfur removal. The coupling bacteria demonstrated a significant remediation effect on river sediment, increasing the TN removal activity by 10 times with a sludge addition ratio of 1:20. The results provide indications for enhancing the nitrogen and sulfur cycle in aquatic environments.