同步硝化厌氧氨氧化反硝化湿法生物处理高氨废气的机理研究

Atmospheric ammonia emission leads to major air pollution problems, such as acid deposition, fog, haze, and greenhouse effect. Physical adsoption, chemical adsoption, catalyzed ammonia decomposition and micro-filtration are commonly used for ammonia gas treatment. High costs, secondary pollutions and low efficiency are the disadvantages of these methods. Thus, it is really necessary to develop a cost-effective and environmental-friendly ammonia gas treatment method. The aim of this project is try to combine chemical adsoprtion and nitrogen bioremoval process. Atmospheric ammonia is transferred into ammonium in liquid face under neutrallty condition in a wet bio-scrubber, which is filled with carriers. Aerobic ammonium oxidizers, anaerobic ammonium oxidizers and denitrifiers can growth on the carriers, where simultaneous partial nitrification, anammox and denitrification processes take place to convert ammonium into di-nitrogen gas, thus, the adsoption solution can be recycled and reused in long-term. Effect of different parameters on nitrogen removal efficiency is analyzed by fingle factor test methods. Cloning, Flrorescence in situ Hybridization (FISH), quantitave PCR and 454 sequencing are equipped to explore the community stucture of nitrogen cycle microbes at different location of the bio-scrubber. Interactions of nitrogen cycle microorganisms and nitrogen removal mechanisms in the bio-scrubber are monitored by stable isotope labeling. By taking all above results into accout, a effecive and environmental-friendly ammonia-rich gas treatment method can be established, which might be an important data base and suggestion for future ammonia gas pollution control. Moreover, this research might give a new outlook for acidic and basic gas treatment.

氨气排入空气会造成酸雨、雾霾及温室效应等诸多污染问题。常见氨气处理方法包括物理吸收、化学吸收、催化（有氧）分解、生物过滤等，但存在处理费用高、二次污染或处理效率低等缺陷。因此，开发一种高效清洁的氨气处理方法已是迫在眉睫。本项目拟将化学吸收法与废水生物脱氮技术相结合，采用填料化工吸收塔在中性条件下湿法将氨气吸收到水相，引入同步硝化厌氧氨氧化反硝化微生物在塔内进行生物脱氮，将实现吸收液的长期循环使用。采用单因素实验，探讨设计运行参数及环境因素对氨气吸收及脱氮效率的影响；通过建立克隆库、荧光原位杂交及功能基因定量PCR、宏基因组测序等分子生物学检测手段，获取氮循环微生物在生物吸收塔内的空间分布规律；应用同位素标记示踪，揭示系统中氮循环微生物相互作用及脱氮过程机理。最终阐述一种高效清洁的高氨废气处理方法，为该法的工程应用提供科学依据并为其他酸碱废气生物处理技术的研究提供借鉴。

含氨废气是工农业生产过程中产生的恶臭有毒气体，排入空气造成严重的大气及水体污染。厌氧氨氧化技术是一种新型生物脱氮工艺，也是生物脱氮领域的重要研究方向。本项目针对现有技术处理氨气的不足，提出处理氨气的同步硝化厌氧氨氧化反硝化工艺（SNAD），将化学吸收法与废水生物脱氮技术相结合，在中性条件下湿法将氨气吸收到水相，通过废水生物脱氮，实现吸收液的长期循环使用，减排二次污染。结果表明：1）以含氨废气为研究对象，在外加亚硝酸盐的条件下，比较直接加入氨气和逐步替代废水中氨氮为氨气两种方法对厌氧氨氧化（anammox）工艺的影响，通过氨气逐步替换模拟废水中的氨氮的方法，可获得更高氨气处理负荷、总氮去除效率并减少N2O排放，最高TN去除率达98%，最高氨氮负荷达到9.63 mmol·d-1，anammox活性为58.4 μmol NH4+·gprot-1·h-1，N2O排放低于0.42%N，远低于硝化、反硝化等工艺，有利于温室气体减排；2）向系统同时投加空气，构建SNAD工艺，最大氨气处理负荷为6.42 mmol·d-1，氧气投加负荷为8.09 mmol·d-1。比较发现，投加氧气前后氨氮去除率由94.1 %升高至97 %，TN去除效率由92.0 %升高至99.4 %，反应器内anammox菌活性未受影响、好氧氨氧化菌活性显著提高（由0至36.1μmol NH4+·gprot-1·h-1），出气中N2O的排放最大值为1.82%N；3）通过厌氧氨氧化与反硝化途径去除的氨分别占68.8%及31.2%。反应器中anammox菌相对丰度最高达到67.7%。本项目是首次采用anammox相关工艺进行氨气生物处理的研究，为氨气去除提供一种可能的高效且经济的解决方案，与硝化-反硝化工艺相比，SNAD工艺可降低能耗（>30 %），减少污泥产量（~90 %），减排温室气体（70-80 %），且不产生含氮废水。