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个人信息
学号 0328301 姓名 朱友兵
学院 城市建设与环境工程学院 专业 环境工程
申请学位 硕士 指导教师 徐国勋(教授);
论文信息
论文标题  悬浮填料-膜生物反应器处理污水的试验研究
Title  无信息
关键词  膜生物反应器 悬浮填料 生物膜 活性污泥 膜污染
Keyword  membrane bioreactor, suspended carrier, biological film, activated sludge , membrane fouling
完成时间  2006年2月 中图号  X7
摘要  众所周知,膜生物反应器在处理污水方面有许多其它水处理工艺难以比拟的优势,但是由于膜污染严重及能耗大等因素一直制约着膜生物反应器的进一步普及和发展。本项研究是通过向传统活性污泥膜生物反应器中投加悬浮填料,用生物膜取代活性污泥,组成生物膜-膜生物反应器处理污水的工艺,观察由这一改变而可能产生的影响,包括对处理工艺和出水水质的影响,同时期望在延缓膜污染方面做一些有益的探索。主要进行了悬浮填料-膜生物反应器处理校园污水的中型试验、悬浮填料-膜生物反应器(MBR)与活性污泥-MBR的小型对比试验,并在改进悬浮填料-MBR的膜污染方面做了一些尝试。研究结果表明:

(1) 一体式悬浮填料-MBR中试装置处理校园污水是可行的。对有机物的去除效果非常好,COD平均去除率达90%,氨氮去除率在90%以上,甚至达到100%的去除率,出水平均COD在25 mg/L以下,浊度接近零。

(2) 悬浮填料-MBR可以采用自然挂膜方式,在试验进水条件下去除COD的异氧菌培养非常快,4d后出水COD稳定在25mg/L以下。而硝化菌的培养所需时间较长,硝化菌具有良好的硝化能力约15d。与活性污泥-MBR比较,启动周期较长。

(3)生物量测试表明在悬浮填料-MBR反应器中附着生物膜上的微生物承担着去除水中污染物的主要角色,而混合液悬浮固体浓度始终维持在较低水平,没有得到明显的增长,这表明悬浮性活性污泥中的微生物在反应器中是受到抑制的。

(4)小型对比试验表明,悬浮填料-MBR的膜污染比活性活性污泥-MBR要严重的多。通过颗粒粒径分布测定和比阻测定,可以解释其原因。经混合液颗粒粒径分布测定,粒径范围在0~1.07μm的小颗粒占悬浮颗粒总数的百分比前者是后者的2倍。混合液比阻测定发现,前者的比阻值要大于后者。尽管后者MLSS浓度远大于前者,但污泥松散、可滤性好。

(5) 增大曝气强度和投加絮凝剂可改善悬浮填料-MBR的膜污染程度,提高出水能力,延长工作周期。

Abstract  Membrane Bioreactor (MBR) is widely known for its many unparrelled advantages in treating the wastewater when compared with other wastewater treatment processes. However MBR have not been used in large scale because of its membrane fouling and energy consuming. In order to extend membrane fouling period, we put suspended carrier into MBR system to change it to a biological film-MBR process and observe the effects brought by this change. Research includes the pilot experiment of suspended-carrier MBR to treat campus domestic wastewater, the small-scale comparative experiment between suspended-carrier MBR and traditional activated sludge MBR. Moreover, some measures have taken to alleviate the membrane fouling of suspended-carrier MBR. The results show that:

(1) The pilot experiment proves integrated suspended-carrier MBR system is feasible to treat domestic wastewater and has good characteristics for removing organics. The system’s average efficiency of removing NH4+-N and COD are 90%, and sometimes 100% for NH4+-N. The average concentration of COD in the effluent is below 25mg/L, and the turbidity is nearly zero NTU.

(2) The suspended-carrier MBR system can culture biological film with natural growth. With the heterotrophic bacteria quick multiplication the concentration of COD in the effluent is stablely below 25mg/L after four days under the influent conditions. But the culture of nitrobacteria needs longer time than that of heterotrophic bacteria, so nitrobacterium culture with good nitrification ability need fifteen days. The startup period of the suspended-carrier MBR system is longer than that of activated sludge MBR system correspondently.

(3) Test of biological mass shows that the microbes in the biological films of suspended-carrier MBR system play an important role in removing pollutant, and the concentration of mixed liquor suspended solids(MLSS) is in low level all along, which shows the microbes in activated sludge is restrained at this reactor.

(4) Comparing the small-scale experiment of suspended-carrier MBR system with activated sludge-MBR system shows membrane fouling of the former is much worse than that of the latter. This reason can be found out through testing the granular size distribution and specific resistance to filtration in mixed liquor. We conclude that the percentage of granular size between 0 to 1.07μm in the suspended-carrier MBR system is two times larger than that of in the sludge-MBR system. We also conclude that the specific resistance to filtration of the former is larger than that of the latter. Though the concentration of MLSS of the former is much lower than that of the latter, activated sludge is looser and more filterable.

(5) Adding flocculant into reactor or enhancing aeration strength could alleviate membrane fouling, resulting in higher effluent flow and longer operation period than before.

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