A^(2)/O工艺中溶解性有机氮的分子转化与生物有效性特征  

Characterization of molecular transformation and bioavailability of dissolved organic nitrogen in the A/A/O process

作　　者：韩成龙 赵凌云 段冰 崔贤 刘彩风 胡海冬 任洪强[1] HAN Cheng-long;ZHAO Ling-yun;DUAN Bing;CUI Xian;LIU Cai-feng;HU Hai-dong;REN Hong-qiang(State Key Laboratory of Pollution Control and Resource Reuse,School of Environment,Nanjing University,Nanjing 210023,China)

机构地区：[1]南京大学环境学院,污染控制与资源化研究国家重点实验室,江苏南京210023

出　　处：《中国环境科学》2023年第4期1610-1619,共10页China Environmental Science

基　　金：国家自然科学基金资助项目(51808281);国家重点实验室导向性合作研究基金项目(PCRR-ZZ-202104)。

摘　　要：本研究探究了厌氧/缺氧/好氧(A^(2)/O)工艺沿程溶解性有机氮(DON)浓度分布及其分子转化规律,并运用多种方法表征了各单元污水DON的生物有效性特征.结果表明,DON浓度由进水(5.3±0.3)mg/L沿厌氧池、缺氧池分别下降至(2.0±0.1),(1.8±0.2)mg/L,而有意思的是好氧池中DON浓度反而升高至(1.9±0.1)mg/L,去除率竟为(-5.6±0.6)%.傅里叶变换离子回旋共振质谱(FT-ICR-MS)分析DON分子组成特征显示,各单元活性DON分子(H/C≥1.5)占比为:厌氧池(38%)<缺氧池(41%)<好氧池(42%),表明好氧池出水DON最不稳定,易被受纳水体中藻类微生物摄取利用.同时在各单元产生的DON分子中,以蛋白/氨基糖类化合物为特征的微生物源DON占比沿程上升,由厌氧池24.77%分别上升至缺氧池29.12%、好氧池33.11%,表明微生物源DON分子是导致好氧池出水DON生物有效性升高的原因.进一步地,采用藻类生物测定厌氧池、缺氧池和好氧池沿程DON生物有效性,分别为(33.2±3.0)%、(34.9±7.0)%和(42.1±4.0)%,该结果证实了FT-ICR-MS的测定结论.此外,主成分分析表明,相比于厌氧池和缺氧池,温度对好氧池DON分子组成具有显著影响,且冬季好氧池出水DON生物有效性(49.3%±2%)高于夏季(42.1%±4.0%).因此,冬季好氧池出水DON具有更高的富营养化潜在风险.The concentration distribution,molecular transformation,and bioavailability characteristics of DON along the anaerobic/anoxic/oxic(A^(2)/O)process were investigated by various methods.The results showed that the concentration of DON decreased from(5.3±0.3)mg/L in the influent to(2.0±0.1)mg/L and(1.8±0.2)mg/L along the anaerobic and anoxic tanks respectively.Interestingly,the concentration of DON in the oxic unit increased to(1.9±0.1)mg/L,and the removal rate was(-5.6±0.6)%.Fourier transform ion cyclotron resonance mass spectrometry(FT-ICR-MS)analysis of the molecular composition of DON showed that the proportion of active DON molecules(H/C≥1.5)in each unit was:anaerobic unit(38%)<anoxic unit(41%)<oxic unit(42%),indicating that the DON in the effluent of oxic unit is the most unstable and easy to be used by algae microbes in the receiving water.At the same time,among the DON molecules produced by each unit,the proportion of microbial source DON characterized by protein/amino sugar compounds increased along the process,from 24.77%to 29.12%and even 33.11%in the oxic unit,indicating that microorganism-derived DON molecules were responsible for the increase in the bioavailability of DON in the effluent of oxic unit.Further,the bioavailability of DON along the A/A/O process was measured by algae,which were(33.2±3.0)%,(34.9±7.0)%and(42.1±4.0)%,respectively.The results confirmed the conclusion of FT-ICR-MS.In addition,the principal component analysis showed that temperature had a significant effect on the molecular composition of DON in the oxic unit compared with the anaerobic and anoxic units,and the bioavailability of DON in the effluent of oxic unit in winter(49.3%±2%)was higher than that in summer(42.1%±4.0%).Therefore,DON in the effluent of oxic unit has a higher potential risk of eutrophication in winter.

关 键 词：溶解性有机氮(DON) 生物有效性 A/A/O工艺 傅里叶变换离子回旋共振质谱(FT-ICR-MS) 分子转化 

分 类 号：X703[环境科学与工程—环境工程]