• 关键词：固定化微生物  低温  河水  脱氮  微生物群落

• 基金项目：国家水体污染控制与治理科技重大专项（No.2017ZX07106004）

• 吕晓冰
• 天津大学环境科学与工程学院，天津 300350

• 李茹莹
• 天津大学环境科学与工程学院，天津 300350

• 摘要：利用微生物净化受污染河水是目前常用的地表水体修复方法，但低温条件下微生物代谢缓慢，酶活性下降，在寒冷季节难以维持对河水的净化效果.本研究采用固定化的方法提高微生物的低温耐受性，通过中试试验考察自然挂膜的固定化微生物、经低温驯化的预挂膜固定化微生物及预挂膜固定化微生物耦合生物促生剂这3种方法对低温河水中COD及氮素类污染物的去除效果.结果表明，在低温条件下3种方法均能有效提升河水的净化效果，静止条件下，河水中COD、NH₄⁺-N、NO₃^--N和TN的去除率由分别由21.3%、37.2%、8.5%和6.9%提升至72.3%~77.9%、48.6%~62.7%、35.3%~42.3%和26.2%~31.9%.COD去除率在2~3 cm·s^-1流速下明显优于静止条件，总氮去除率在2 cm·s^-1流速下最高.自然挂膜和预挂膜微生物对河水中污染的去除无明显差别，添加促生剂对固定化微生物的净化作用没有进一步的提升，但功能菌群的微生物群落结构有所不同.促生剂的添加提高了河水中的微生物活性与群落多样性，但对固定化载体上的微生物无明显影响.固定化载体上的优势菌群均为低温下具有脱氮功能的Proteobacteria.此外，具有低温适应性的脱氮功能菌属Rhodoferax、Pedobacter及Pseudomonas在3组固定化载体上均有较高丰度，而自然挂膜的载体上及其河水中分别对Malikia属及hgcI_clade属具有显著特异性的富集（p<0.05），这两种菌属均具有低温脱氮功能.

• Abstract：Biological treatment is commonly used for river water remediation. However， purification efficiency would decrease in cold seasons because of the slow microbial metabolism and low enzyme activity at a low temperature. In this study， immobilization was used to improve the tolerance of microorganisms to the low-temperature. Pilot experiments were conducted to investigate the removal of COD and nitrogen at the low-temperature by in-situ immobilized microorganisms， pre-immobilized microorganisms with low-temperature acclimation and pre-immobilized microorganisms coupled with bio-energizer. Results showed that the three methods could effectively improve the purification of river water under low temperature conditions. At stationary condition， the removal efficiencies of COD， NH₄⁺-N， NO₃^--N and TN increased from 21.3%、37.2%、8.5% and 6.9% to 72.3%~77.9%、48.6%~62.7%、35.3%~42.3% and 26.2%~31.9%， respectively. COD removal under 2~3 cm·s^-1 flow rates was obviously better than that under static conditions， and the removal efficiency of TN at 2 cm·s^-1 flow rate was the highest. There was no obvious difference in the removal of pollutants between the in-situ immobilized and pre-immobilized microorganisms， and the addition of bio-energizer had no further improvement on the purification performance， but the functional microbial community structure was changed. The addition of bio-energizer increased the activity and diversity of microorganisms in river water， but had no significant effects on the microorganisms on the immobilized carrier. The dominant bacteria on the immobilized carrier were Proteobacteria with nitrogen removal function at low temperature. In addition， Rhodoferax， Pedobacter and Pseudomonas， which could remove nitrogen at low temperature， also have relatively high abundances in the three groups of immobilized microorganisms， while Malikia and hgcI_clade had significantly specific enrichment in the in-situ immobilized microorganisms and suspended bacteria in the river water， respectively （p<0.05）， both of them had the function of nitrogen removal at low temperature.

• Key words：immobilized microorganisms  low-temperature  river water  nitrogen removal  microbial community

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