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盐度变化对含氨氮废水处理的影响

Effects of Salinity Variation on the Treatment Wastewater Containing Ammonia

【作者】 邹高龙

【导师】 李小明;

【作者基本信息】 湖南大学 , 环境工程, 2008, 硕士

【摘要】 含盐废水包括海水直接利用后排放出的废水和许多工业废水,如化工废水、农药废水。因为含有一定的无机盐,而无机盐对生物有抑制作用,可以造成质壁分离或细胞失活。国外对高盐废水生化处理的研究起步较早,但是并没有得到一致的结论,其主要分歧在于微生物对高盐度环境适应能力的强弱以及不同浓度不同种类的盐份对处理系统的影响也不一样。若采用生物法处理高含盐有机废水,首先应解决微生物能够适应高盐度环境的问题,并最终实现去除废水中有机污染物的目的。目前国内外对高盐度废水的研究主要是针对COD降解的研究,而对NH3-N的研究还处于初始阶段,并没有深入的研究,有些还存在分歧,造成这种分歧的原因是对污泥适应盐份的生物学机制缺乏了解,在实验中可能由于采用的驯化方法、盐浓度以及具体的实验条件不一致而导致的。本论文主要针对盐度变化对SBR中硝化作用的动态影响和盐度变化对SBBR和SBR中含氨氮废水处理的影响展开研究,为含盐废水中的氨氮处理提供理论依据。本研究针对含盐废水的硝化作用,通过在单级SBR反应器中,逐步增加盐度(以氯离子浓度计)驯化活性污泥过程、淡水活性污泥受到一定盐度冲击过程以及经过3×104 mg Cl·L-1驯化后的活性污泥在盐度波动时对亚硝化和硝酸化过程的影响。研究结果表明:在逐步提高盐度驯化的过程中,NH4+-N的降解速率在盐度为1.5×104 mg Cl·L-1-2.0×104 mg Cl·L-1时先降低后升高,当盐度为2.5×104 mg Cl·L-1时,反应周期末有大量的NO2--N累积,当盐度高达3.0×104 mg Cl·L-1时, NH4+-N的降解速率仍然维持在一定水平,这说明硝酸化过程比亚硝化过程更容易受到高盐度的抑制。而在冲击实验中,当淡水活性污泥受到2×104 mg Cl·L-1盐度冲击时,即使经过长时间的驯化后亚硝化过程仍然受到较大的抑制,且周期末有大量NO2--N累积,当受到3×104 mg Cl·L-1时硝化作用几乎完全被抑制。经过3×104 mg Cl·L-1驯化后的活性污泥的硝化作用对盐度波动具有较强的适应性。研究了逐步提高盐度(以氯离子浓度计)对内循坏SBBR和SBR中硝化和反硝化作用的影响,以及当盐度降为0 mg Cl·L-1后的恢复过程。研究结果表明:在内循坏SBBR和SBR中,随着盐度的逐步提高,亚硝化过程都会受到影响,当盐度小于1.0×104mg Cl·L-1时,SBBR中的氨氮降解速率小于SBR,从1.5×104mg Cl·L-1开始SBBR中的氨氮降解速率大于SBR,当盐度提高为4.0×104mg Cl·L-1时,两者的亚硝化过程都受到极大抑制; SBBR在盐度为1.5×104mg Cl·L-1时即持续有NO2--N累积,而在SBR中,当盐度提高为2.5×104mg Cl·L-1时,反应周期末才开始持续有大量的NO2--N累积;在SBBR中,当盐度低于1.5×104mg Cl·L-1时,TN去除率达到60%左右,当盐度大于3.0×104mg Cl·L-1时,同步硝化反硝化过程受到较大抑制。本论文还研究了盐度变化对活性污泥理化性质及微生物生理群和种属的影响分析了盐度变化时的活性污泥形态结构、污泥浓度以及污泥沉降指数,还分析了不同盐度时的亚硝酸菌和硝酸菌菌种变化。

【Abstract】 Many kinds of waste water containing highly concentrated salt, such as municipal wastewater in cities utilizing sea water as one part of water supply, chemical industrial wastewater and pesticide wastewater,etc. Because it contains salt,high saline concentrations have negative effects on organic matter, nitrogen and phosphorus removal. The presence of high salt concentrations in wastewaters induces salt stress to the microbial species, results in the inhibition of many enzymes, decreases cell activity and eventually leads to plasmolysis.The time when they started to study disposing wastewater contains high salt by biochemistry is early overseas,but there is not a consolidate conclusion, the great difference is about the adaptability of microorganism in high saline concentration and the affection to wastewater facilities for different saline concentration and different type of salt. If we deal with the high saline concentration wastewater by biology,the microorganasim should live with high salt,so as to dispose organic substance. Most of the literature reports emphasize only on the effect of salinity on the decrese of COD,but it is few about the decrease for ammonia,most important,there is contradictory interpretation of results,the reason for the contradiction is lack of knowledge how the activated sludge to adapt high salt,and the different of the way for domestication,saline concentration and experiment condition might lead to the wrong conclusion in the experimentation.This paper disscused the dynamic response of nitrification to salinity changed in SBR and effects of salinity variation on the treatment wastewater containing ammonia in the SBBR and SBR. We try to find out the theory for treating ammonia in high saline wastewater.In the process of nitrification aiming at saline sewage, we discussed the response of ammonia-oxidize and nitrite-oxidize to increased chloride concentration gradually or increased once to a certain concentration in the salt-free wastewater in SBR. We also discussed the dynamic response of ammonia-oxidize and nitrite-oxidize to changed the chloride concentration after the microorganisms were trained by 3×104 mg Cl·L-1.It was found that the speed of ammonia-oxidize had a trend of down-and-up between 1.5×104 mg Cl·L-1and 2.0×104 mg Cl·L-1in the process of increasing chloride stepwise. When the chloride concentration was 2.5×104 mg Cl·L-1, there were a lot of nitrite at the end of cycle, when the chloride concentration was 3.0×104 mg Cl·L-1,the speed of ammonia-oxidize can keep a good level. So nitrite-oxidize are easier inhibited by a high chloride concentration than ammonia-oxidize. When impulsed 2×104 mg Cl·L-1in the fresh activated sludge ,the process of ammonia-oxidize was inhibited strongly and there existed nitrite at the end of cycle. When impulsed 3×104 mg Cl·L-1in the fresh activated sludge, nitrification was inhibited completely. After the culture was trained with 3×104 mg Cl·L-1 increasing chloride concentration gradually, though the chloride concentration fluctuated(less than 3×104 mg Cl·L-1), the process of ammonia-oxidize and nitrite-oxidize have strong adaptability.According to nitrogen-containing wastewater, in this study effects of salinity variation on nitrification and denitrification in internal circulation Sequencing Batch Biofilm Reactor (SBBR) and Sequencing Batch Reacto (SBR), and the process of recovery as decreased salinity. The results showed that nitrosation process was effected in internal circulation SBBR and SBR as the increase of salinity, and as the salinity less than 1.0×104 mg Cl·L-1, the speed of ammonia-oxidize would be quicker in the SBR than in the SBBR, but the state would be opposite as the salinity beyond 1.5×104 mg Cl·L-1. As the salinity increased to 4.0×104 mg Cl·L-1,the process of ammonia-oxidize was restrained strongly both in SBBR and SBR.The nitrite accumulation was attained continually as the salinity at 1.5×104mg Cl·L-1 and 2.5×104 mg Cl·L-1 in the SBBR and SBR respectively. In the SBBR, the removal rate of TN was about 60% as the salinity was less than 1.5×104 mg Cl·L-1, and the SND was restrained strongly as the salinity beyond 3.0×104 mg Cl·L-1.This paper also discussed long term effects of salt on population structure and floc characteristics in enriched bacterial cultures of nitrifiers,and we analysis the activated sludge configuration struction、sludge concentration、SVI、the composition of ammonia-oxidizer and nitrite-oxdizer changed when salt changed.

  • 【网络出版投稿人】 湖南大学
  • 【网络出版年期】2009年 08期
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