Wang Chao, Yu Cong, Qiao Sen
Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education, China), School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024, China.
Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education, China), School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024, China.
J Environ Manage. 2025 Sep;392:126782. doi: 10.1016/j.jenvman.2025.126782. Epub 2025 Aug 1.
This study presented a novel strategy employing sulfide (NaS) as the external electron donor and enzyme activity inhibitor to enhance nitrogen removal and enable nitrous oxide (NO) recovery in low carbon-to-nitrogen (C/N) ratio wastewater treatment. With the addition of NaS, the system achieved a maximum total nitrogen (TN) removal of 100.0 % while accumulating nitrogen oxide (NO) and elemental sulfur (S) at an average yield of 60.5 % and 69.1 %, respectively. Systematic investigations under varying NaS concentrations (0.0-225.0 mg S/L) and C/N ratios (1.0:0.0-6.0:1.0) demonstrated that C/N ratio and NaS concentration had significant effects on the nitrogen removal performance and microbial community; high concentration of NaS (225.0 mg-S/L) would inhibit nitrogen removal efficiency, and with the decrease of C/N ratio and increase of NaS concentration, the microbial community structure gradually shifted from heterotrophic bacteria to autotrophic bacteria. Transcriptomic analysis revealed that NaS addition suppressed nitrous oxide reductase (NOR) activity (0.52 ± 0.04 μmol N/(min mg protein) → 0.23 ± 0.03 μmol N/(min mg protein)) and downregulated the nosZ gene cluster (-4.53), redirecting electron flux toward sulfur oxidation pathways dominated by sulfide:quinone oxidoreductase (SQR), favoring NO accumulation. By integrating autotrophic denitrification with targeted NO and S recovery, this work established a sustainable framework for low-C/N wastewater treatment, eliminating organic carbon dependency and transforming nitrogen pollution into valorized resources, contributing to the optimization of sulfur-mediated biological nitrogen removal (BNR) processes, and providing promising insights for economy-driven wastewater management.
本研究提出了一种新策略，即采用硫化物（NaS）作为外部电子供体和酶活性抑制剂，以提高低碳氮比（C/N）废水处理中的氮去除率并实现氧化亚氮（N₂O）回收。添加NaS后，该系统实现了100.0%的最大总氮（TN）去除率，同时分别以60.5%和69.1%的平均产率积累氮氧化物（NO）和元素硫（S）。在不同NaS浓度（0.0 - 225.0 mg S/L）和C/N比（1.0:0.0 - 6.0:1.0）下进行的系统研究表明，C/N比和NaS浓度对氮去除性能和微生物群落有显著影响；高浓度的NaS（225.0 mg-S/L）会抑制氮去除效率，并且随着C/N比的降低和NaS浓度的增加，微生物群落结构逐渐从异养细菌向自养细菌转变。转录组分析表明，添加NaS会抑制氧化亚氮还原酶（NOR）活性（从0.52 ± 0.04 μmol N/(min mg蛋白)降至0.23 ± 0.03 μmol N/(min mg蛋白)）并下调nosZ基因簇（-4.53），使电子流转向以硫化物：醌氧化还原酶（SQR）为主导的硫氧化途径，有利于NO积累。通过将自养反硝化与有针对性的NO和S回收相结合，本研究建立了一个可持续的低碳氮比废水处理框架，消除了对有机碳的依赖，并将氮污染转化为有价值的资源，有助于优化硫介导的生物脱氮（BNR）工艺，并为经济驱动的废水管理提供了有前景的见解。
