硫耦合自养反硝化与硫酸盐还原系统：提升氮和硫去除效率及微生物群落分析

Abstract

A coupled S 0 AD and SR system was constructed for denitrification of low C/N ration wastewater. • The coupled system enhanced denitrification performance and reduced the sulfate concentration in the effluent. • The reflux in the coupled system altered the microbial community structure. • Enhanced synergistic metabolic activities between AOB and SRB underpinned the overall system improvement. Elemental sulfur autotrophic denitrification (S0AD) offers high nitrate (NO₃⁻–N) removal efficiency but generates substantial sulfate (SO₄²⁻) as a by-product. To mitigate this secondary pollution, an S0AD reactor and a sulfate-reducing (SR) reactor were connected in series to establish a coupled system, with the effluent from the SR reactor subsequently recirculated back to the S0AD unit. The efficiency of nitrogen and sulfate removal varied markedly with the reflux ratio (0%, 43%, and 233%). Compared with the standalone S0AD system, a reflux ratio of 43% was identified as the optimal operating condition, yielding a peak nitrogen removal efficiency of 97.7% and reducing effluent sulfate by 43.9%. Microbial analysis revealed a profound shift in community composition: the coupled S0AD reactor transitioned from a Thermithiobacillus-based autotrophic community to an Acetobacter-dominated mixotrophic consortium, while the SR reactor enriched Lacticaseibacillus. Genetically, this was supported by elevated norB and norC abundances in the S0AD unit and stable dsrA and dsrB levels in the SR unit. This study demonstrates a high-performance strategy for synergetic nitrogen and sulfur removal, providing a sustainable and environmentally friendly solution for the advanced treatment of industrial wastewater. Download: Download high-res image (183KB) Download: Download full-size image