磷对硫自养反硝化效果的影响

为探究硫自养反硝化所需的最低磷浓度，对硫自养反硝化系统进行磷饥饿处理，给予不同磷浓度的进水，考察磷浓度对硫自养反硝化效果和微生物群落结构的影响。结果表明：随着磷饥饿期的延长，$ {mathrm{N}mathrm{O}}_{x}^{-} $-N去除率由饥饿前的98.1%～99.6%逐步降至24.8%～49.6%，且出水中随之出现亚硝酸盐的积累。补充磷后，$ {mathrm{N}mathrm{O}}_{x}^{-} $-N去除率随进水磷浓度的增加显著提升，且进水磷浓度越高，$ {mathrm{N}mathrm{O}}_{x}^{-} $-N去除率能越快恢复至饥饿前水平（98%以上），出水中的亚硝酸盐氮浓度也越快降至饥饿前水平（不足0.05 mg/L）。当进水中磷浓度不低于0.200 mg/L时，硫自养反硝化效率不受磷浓度限制。磷浓度影响硫自养反硝化系统的微生物多样性，磷恢复处理组的物种多样性和丰度均显著高于磷饥饿处理组。在磷恢复处理组中，硫自养反硝化相关的功能菌属是优势菌属，相对丰度占45.78%，而在磷饥饿处理组中，该功能菌属相对丰度仅占4.67%，磷浓度极大地影响了硫自养反硝化系统中的硫自养反硝化相关功能菌的相对丰度。

Influence of phosphorus on the performance of sulfur autotrophic denitrification

In order to explore the minimum requirement of phosphorus for sulfur autotrophic denitrification, the sulfur autotrophic denitrification system was first treated with phosphorus starvation, and then the influents of different phosphorus concentrations were provided to investigate the influence of phosphorus concentration on the sulfur autotrophic denitrification performance and microbial community structure. The results showed that with the extension of the phosphorus starvation period, $ {mathrm{N}mathrm{O}}_{x}^{-} $-N removal efficiency declined gradually from 98.1%-99.6% before phosphorus starvation to 24.8%-49.6% after phosphorus starvation, accompanied by an accumulation of nitrite in the effluent. After phosphorus addition, $ {mathrm{N}mathrm{O}}_{x}^{-} $-N removal efficiency increased significantly with increasing influent phosphorus concentration. The higher the influent phosphorus concentration, the faster the $ {mathrm{N}mathrm{O}}_{x}^{-} $-N removal efficiency and effluent nitrite concentration recovered to the level before phosphorus starvation, with more than 98% and less than 0.05 mg/L, respectively. The efficiency of sulfur autotrophic denitrification was not limited by phosphorus concentration when the influent phosphorus concentration was not lower than 0.200 mg/L. The phosphorus concentration affected the microbial diversity of the sulfur autotrophic denitrification system, and the community diversity and richness of the sulfur autotrophic denitrification group recovered from phosphorus starvation were significantly higher than that of the group under phosphorus starvation. The functional genera related to sulfur autotrophic denitrification were the predominant genera in the sulfur autotrophic denitrification group recovered from phosphorus starvation, with the relative abundance accounting for 45.78%, while the relative abundance only accounted for 4.67% in the group under phosphorus starvation. The phosphorus concentration greatly affected the relative abundance of functional genera related to sulfur autotrophic denitrification in the sulfur autotrophic denitrification system.