| 摘要: |
| 【目的】 研究ZnO纳米颗粒对活性污泥脱氮效果及硝化细菌丰度的影响，以揭示ZnO纳米颗粒对活性污泥脱氮系统的影响机制。【方法】 向模拟的4 L SBR反应器内投加1，10，20 mg/L ZnO纳米颗粒悬液，以未投加ZnO纳米颗粒的反应器为对照（CK），测定不同质量浓度ZnO纳米颗粒处理的活性污泥NH+4 N和总氮（TN）、硝化速率的变化；最后采用荧光原位杂交技术（FISH），对不同质量浓度ZnO纳米颗粒处理下活性污泥中硝化细菌（氨氧化细菌(Ammonia Oxidizing Bacteria，AOB)和亚硝酸氧化菌(Nitrite Oxidizing Bacteria，NOB)）的丰度水平进行检测。【结果】 1，10，20 mg/L ZnO纳米颗粒悬液短期(<6 h)暴露下对活性污泥脱氮效果没有明显影响；活性污泥经10，20 mg/L ZnO纳米颗粒悬液长期接触（30 d）后，TN去除率由投加前的81.4%，80.5%分别下降至66.1%，47.4%，NH+4 N去除率由投加前的80.4%，84.3%分别下降至62.1%，53.4%。随着ZnO纳米颗粒质量浓度的增加，硝化速率也明显下降。FISH定量分析表明，长期（30 d）暴露于10~20 mg/L的ZnO纳米颗粒环境中，活性污泥中的AOB和NOB丰度水平大幅降低，60 d后略有回升。【结论】 10~20 mg/L ZnO纳米颗粒悬液对脱氮菌群生长和代谢活性均产生较明显的抑制作用，这是活性污泥脱氮效果明显降低的主要原因。 |
| 关键词: ZnO纳米颗粒 活性污泥 脱氮效果 硝化速率 硝化菌丰度 |
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| Effects of ZnO nanoparticles on nitrogen removal efficiency and nitrifying bacteria abundance of activated sludge |
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YAN Jian-wen,XU Chuan-zhao
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| Abstract: |
| 【Objective】 This study investigated the effects of ZnO nanoparticles (ZnO NPs) on nitrogen removal efficiency and nitrifying bacteria abundance of activated sludge to reveal the mechanism how ZnO nanoparticles affect the active sludge denitrification system.【Method】 ZnO NPs with concentrations of 1,10,and 20 mg/L were added to 4 L SBRs,and the SBR without ZnO NPs was used as control (CK).The changes of NH+4 N and TN,and nitrification rate were measured.The fluorescence in situ hybridization (FISH) technology was adopted to test the Ammonia Oxidizing Bacteria (AOB) and Nitrite Oxidizing Bacteria (NOB) abundance levels in active sludge denitrification system with different ZnO NPs concentrations.【Result】 1,10 and 20 mg/L ZnO NPs had no notable effects on activated sludge denitrification performance with short term exposure (<6 h).With the long term exposure (30 d) of 10 and 20 mg/L ZnO NPs,TN removal efficiency decreased from 81.4% and 80.5% to 66.1% and 47.4%,NH+4 N removal rate decreased from 80.4% and 84.3% to 62.1% and 53.4%,and denitrification rate decreased as well.FISH quantitative analysis showed that the activity and ammonia oxidizing bacteria abundance were significantly reduced after the exposure to 10-20 mg/L ZnO NPs (30 d),and increased slightly after 60 d.【Conclusion】 10 and 20 mg/L ZnO NPs had notable inhibition on the growth and metabolic activity of nitrifying bacteria,resulting in the decrease of nitrogen removal efficiency in activated sludge. |
| Key words: ZnO nanoparticles activated sludge denitrification rate ammonium uptake rate nitrifying bacteria abundance |
