| 苯并[a]芘厌氧降解的苯酚共基质协同作用与污泥微生物特性 |
| 摘要点击 1371 全文点击 653 投稿时间：2017-12-19 修订日期：2018-01-19 |
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| 中文关键词 市政污泥 焦化污泥 苯并[a]芘(BaP) 苯酚 共基质 微生物群落 多环芳烃 |
| 英文关键词 municipal sludge coking sludge benzo[a]pyrene(BaP) phenol co-substrate microbial communities polycyclic aromatic hydrocarbons(PAHs) |
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| 中文摘要 |
| 苯并[a]芘（BaP）是焦化废水中PAHs的典型代表，也是行业优先控制的污染物，其微生物响应特性以及降解的促进方法值得研究；新建焦化废水处理工程的调试运行，接种的污泥多来源于市政污泥或其他焦化厂的污泥，目前缺乏不同污泥微生物特性、有效性及其影响条件的考察.针对上述观点，选用厌氧反应器，分别采集某焦化废水处理厂以及市政污水处理厂的厌氧活性污泥，研究比较市政污泥和焦化污泥对BaP的耐受及降解能力，以10 mg·L-1的BaP为唯一碳源及添加苯酚作为共基质，进行BaP的微生物降解与动力学实验，用高通量测序技术分析了两种污泥在降解实验前后的微生物群落结构，阐明其变化.研究结果表明：两种污泥都能降解BaP，苯酚共基质促进了降解效果；市政污泥的降解效率要好于焦化污泥，以BaP为唯一碳源时，市政污泥和焦化污泥的半衰期分别为116.3 d、155.41 d，加入苯酚后，半衰期分别为38.44 d、81.25 d；群落测序分析表明，两种污泥经BaP驯化后，群落组成都发生了较大变化，市政污泥变化远大于焦化污泥；焦化污泥经BaP驯化后，微生物的优势菌属和驯化前差别不大，且其优势菌属都是已经报道的能够降解PAHs的菌属；市政污泥经过同样的驯化以后，微生物的优势菌属和驯化前差别较大，丰度占比最大的并不是常见的PAHs降解菌类；作为PAHs的常见降解菌属，Bacillus sp.、Pseudomonas、Achromobacter以及Sphingomonas sp.在两种污泥中均能被鉴定出来，其百分含量比较靠前.综合研究结果认为，未经过焦化废水毒性抑制的市政污泥在对BaP的利用上更活跃，被理解为是更多种类的微生物参与到了对污染物的降解；苯酚的存在会促进BaP等PAHs的降解，获得的启示是富集了PAHs的焦化污泥排出系统后可以通过生活污水与苯酚的共同添加实现减量化处理. |
| 英文摘要 |
| Benzo[a]pyrene (BaP) is a typical representative of PAHs in coking wastewater and priority-controlled pollutants in the coking industry; its response characteristics with microorganisms and the methods to promote its degradation are worth studying. On the other hand, because the inoculated sludge for the adjustment and operation of newly-constructed coking wastewater treatment plants comes from municipal sludge or other coking plants, currently, the study of the microbial properties of different sludges', sludge availability, and the conditions that influence these properties are lacking. On account of the above perspectives, an experiment to study and compare the durability of municipal sludge and coking sludge, and their ability to degrade BaP was carried out. An anaerobic reactor was selected for the experiment and anaerobic-activated sludges were collected from a coking wastewater processing unit and a municipal wastewater plant. Then, 10 mg·L-1 of BaP alone and BaP with phenol as a co-metabolic carbon source was added to the coking and municipal sludge samples, respectively, for comparison experiments to study the microbial degradation of BaP and its dynamics. Moreover, high-throughput sequencing technology was also used to analyze the changes in the microbial community structure before and after the degradation experiment. The results showed that:① Both sludges were capable of degrading BaP, but municipal sludge showed a higher degradation efficiency than coking sludge; ② Adding phenol as co-substrate promoted the biodegradation of BaP in both sludges. When BaP was the sole carbon source, the half-life of BaP in the two sludges was 155.41 d and 116.3 d respectively. After the addition of phenol, the half-life was reduced to 81.25 d and 38.44 d, respectively; ③ According to the analysis of the microbial community structure, the community composition in both sludges changed markedly. Moreover, the microbial community in the municipal sludge showed a more evident change than that of the coking sludge. In the coking sludge, the dominant bacteria community changed a little after acclimation, most of the observed bacteria were previously reported common PAH-degrading strains. In contrast, the dominant bacteria community in the municipal sludge varied greatly after acclimation, and the most abundant bacteria were not common PAH-degrading strains. In addition, some frequently reported PAHs-degrading bacteria such as Bacillus sp., Pseudomonas, Achromobacter, and Sphingomonas sp., were identified in both the sludges and were present in high abundance. The results indicated that municipal sludge utilized BaP more actively than coking sludge; this phenomenon can be explained by the fact that municipal sludge contained a higher diversity of microbes that were involved in the degradation of BaP. Furthermore, the presence of phenol promoted the degradation of PAHs like BaP. Therefore, we proposed that the PAHs in coking sludge discharge might be reduced by the addition phenol and municipal wastewater. |
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