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活性污泥工艺降解壬基酚聚氧乙烯醚的实验研究

Study on Degradation of Nonylphenol Ethoxylates by Actived Sludge Process

【作者】 靖春明

【导师】 朱彤;

【作者基本信息】 东北大学 , 化工过程机械, 2008, 硕士

【摘要】 壬基酚聚氧乙烯醚(Nonylphenol Ethoxylates, NPnEO,n为聚合度)由壬基酚和环氧乙烷加合而成,其表面活性主要来自于壬基酚的疏水性和对位取代长链上乙氧基重复单元的亲水性,是目前全球商用第二大类的非离子表面活性剂,因其具有性质稳定、耐酸碱等特征,广泛应用于工业(如纺织、塑料、造纸等)、农业和日常生活(家用洗化用品)。它进入水体环境后可经生物降解去除亲水的乙氧基部分,形成中间代谢产物壬基酚。与母体化合物相比,壬基酚具有难降解特性及疏水性、脂溶性和生物累积性。对生物体表现出雌激素活性,干扰体内正常激素的作用,属环境内分泌干扰物质(Endocrine Disrupting Chemicals, EDCs)。本研究采用A/O工艺,利用活性污泥法降解NPnEO,实验过程中定期改变运行参数,并在每次参数改变前检测各项水质指标,评价A/O工艺对壬基酚聚氧乙烯醚的处理效果,优化运行工艺参数,达到实验运行工艺参数最优化的效果。实验过程中,在原水中逐步增加NPnEO浓度,随着活性污泥对NPnEO的逐步适应,污泥性状逐步趋于稳定。NPnEO浓度的逐渐增大对各项水质指标也造成了影响,随着NPnEO浓度的增大,COD、TN的去除率都有所下降,伴随着NPnEO浓度逐步稳定之后,各项水质指标也逐渐稳定。A/O工艺中的活性污泥经过短期驯化既可对NPnEO有良好的降解效果,但是NPnEO浓度的大幅度变化会导致去除率的明显下降。实验表明,利用A/O工艺处理NPnEO,NPnEO会发生最终生物降解,苯环结构被破坏,并在活性污泥吸附的共同作用下,对其降解产物也具有有良好的处理效果。本研究还利用了正相高效液相色谱法分离检测处理水中壬基酚聚氧乙烯醚及其生物降解产物,分析微生物对NPnEO降解效果。建立了一种以正相高效液相色谱等强度洗脱分离检测壬基酚和短链壬基酚聚氧乙烯醚的新方法。本研究的实验指标是NPnEO的降解率,根据初始分析,利用活性污泥法降解NPnEO,影响其降解率的主要运行参数是温度、溶解氧、水力停留时间、污泥龄。每个因素分别取5个水平做实验,建立正交表,利用正交实验优化系统关键运行参数。

【Abstract】 Nonylphenol Ethoxylates are accomplished by Nonyl Phenol and Ethylene Oxide. Surface activity mainly comes from the sparse ability in swimming in nonylphenol and hydrophily of an Repeating element in Second oxygen base on contrapuntal go ahead replacing long-chain. Because it has some stability characteristics such as Acid proof alkali, Applied to industry broadly such as Spinning and weaving, Spinning and weaving, making plastic and paper, and agriculture and daily life such as clearing melt articles using family. After entering the wave environment, it may dislodge second oxygen base part loving water after living things degradation, and form centre supersession outcome. Compared with mother’s body compound, Nonylphenol have property characteristics such as difficult degradation, the sparse ability in swimming, The grease dissolves nature and bioaccumulation. It shows estrogen activity to the living things body,the grease dissolves nature, was of Endocrine Disrupting Chemicals,EDCs.In the experiment, A/O process is considered. It works under optimal conditions. And micro-biological degradation of NPnEO by A/O process is evaluated. In the same time, NPnEO degradation flora is cultured and analysed. The experimental results show that the state of activated sludge will be affected with increase of NPnEO in raw water. But with the adaption of activated sludge, the state will gradually be improved and indicators of the state of activated sludge will be more stable. When the density of NPnEO becomes higher, various indicators of water quality will also be impacted. Removal rate of COD and TN will drop. With the concentration of NPnEO being stable, removal rate of COD will rebound and removal rate of TN will also be stable. Removal of NPnEO by A/O process is obvious after a short-term acclimation. But change of concentration of NPnEO will lead to substantial change of removal rate. During the course, ultimate micro-biological degradation of NPnEO will happen and the structure of benzene ring will be destroyed. Both ultimate micro-biological degradation and adsorption of activated sludge lead to satisfying removal rate.In this study, modern molecular biology techniques are used such as PCR and DGGE to analysis structural changes of microbial flora in the process. It is found that with concentration changes of NPnEO in raw water structure of microbial flora will change too. The number of bands in DGGE will decrease. Dice coefficient of both of the two pools will be smaller. However, with the stability of concentration of NPnEO, dice coefficient of the two pools will increase. The structure of microbial flora will be relatively stable. And ultimately we get the microbial flora that adapt for degradation of NPnEO and its intermediate products.

  • 【网络出版投稿人】 东北大学
  • 【网络出版年期】2012年 03期
  • 【分类号】X703
  • 【下载频次】108
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