以N-甲基吡咯烷酮(NMP)为电子供体进行反硝化的可行性及实验研究

Feasibility of N-methylpyrrolidone (NMP) as an electron donor for denitrification

摘要:

【目的】利用N-甲基吡咯烷酮(N-methylpyrrolidone, NMP)作为电子供体进行反硝化实验，以实现废水资源化。【方法】分别将NMP废水和葡萄糖作为电子供体加入到模拟的城市污水处理尾水中进行反硝化，比较2种电子供体去除硝酸盐的规律。同时考查NMP在反硝化过程中的氮素释放规律，并对所释放的氮素进行后续处理。最后再对它们作为电子供体时的反硝化污泥采用高通量测序，从微生物群落的角度分析NMP作为电子供体时其作用机理是否相同。【结果】当以NMP为电子供体时，硝酸盐氮的去除速率比葡萄糖为电子供体时要快67%。在8 h的反硝化结束后，剩余的硝酸盐氮、累积的亚硝酸盐氮和NMP本身所释放氨氮之和的总氮，与葡萄糖为电子供体时相近。【结论】NMP废水可以作为电子供体用于城镇污水处理厂的深度脱氮。对2种碳源所驯化的反硝化污泥样品进行高通量分析表明，NMP与葡萄糖作为电子供体用于反硝化反应时，相关的作用机理是不同的。该项研究结果对利用含氮杂环化合物作为电子供体进行反硝化具有重要的理论指导意义。

Abstract:

[Objective] N-methylpyrrolidone (NMP) was used as an electron donor for denitrification to treat wastewater. [Methods] NMP and glucose as electron donors were respectively added into the simulated effluent from wastewater treatment plant for denitrification, during which they were compared for the removal of nitrates. The fate of nitrogen released during the denitrification was studied, and the released nitrogen was further treated. Furthermore, we submitted the sludge samples acclimated with NMP and glucose for high-throughput sequencing to investigate their mechanisms of denitrification. [Results] The NMP-acclimating sludge showed the nitrate-N removal rate 67% higher than the glucose-acclimating sludge. After 8 h of denitrification with NMP as the electron donor, the total nitrogen (TN) composed of residual nitrate N, generated nitrite N, and released ammonium N from NMP biodegradation was similar to the TN after the denitrification with glucose as the electron donor. [Conclusion] The wastewater containing NMP could be used as the electron donor for deep nitrate removal, although it was directly treated as the wastewater before. High-throughput sequencing indicated that NMP was different from glucose in the mechanism of denitrification when being used as the electron donor. As one of the nitrogen-containing heterocyclic compounds, NMP releases the electron donor for denitrification through the biodegradation of organic acids after the cleavage of NMP ring. However, glucose releases its electron donor for denitrification through the biodegradation without ring cleavage because of its simple structure. The results have theoretical significance for utilizing nitrogen-containing heterocyclic compounds as electron donors for denitrification.