中国科学院生态环境研究中心机构知识库
Advanced  
RCEES OpenIR  > 水污染控制实验室  > 学位论文
题名: MABR处理城市污水与垃圾渗滤液混合污水生物膜特性研究
作者: 袁栋栋
学位类别: 博士
答辩日期: 2011
授予单位: 中国科学院研究生院
授予地点: 北京
导师: 樊耀波
关键词: 膜曝气生物膜反应器(MABR) ; membrane-aerated biofilm reactor (MABR) ; 生物脱氮 ; biological nitrogen removal ; 生物膜特征 ; biofilm characteristics ; 膜组件 ; membrane module ; 异向扩散 ; counter diffusion
其他题名: Biofilm characteristics of Membrane-Aerated biofilm reactor co-treating landfill leachate and domestic sewage
中文摘要:       垃圾渗滤液是难处理的废水,因此一些城镇将其与城市污水合并处理。由于垃圾渗滤液中含有高浓度氨氮,与城市污水混合后会使混合污水的COD/NH4+-N偏低,导致常规生物处理工艺出水TN超标等问题。膜曝气生物膜反应器(MABR)具有氧与机制异向传质的独特性能,在单一生物膜内形成了相互协同的功能分区,有利于低碳氮比污水的脱氮。因此,本研究以城市污水与垃圾渗滤液混合污水为对象,开展了MABR的性能和膜曝气生物膜(MAB)特征的研究,以期得到MABR工艺优化的操作参数和明确的运行机理,为工艺的调控提供科学依据。 设计了不同构型膜组件,研究了膜丝间距和膜丝长度,以及膜的供气压力对MABR性能的影响,为后续实验确定了最佳膜丝间距与长度,分别为4.7 mm和70 cm。 MABR启动阶段生物膜的形成特性研究表明其形成及生长过程满足传统生物膜生长遵循的S形规律;在生物膜形成初期,多糖的粘附对生物膜形成有重要作用,而随着生物膜的增殖,蛋白质等疏水性物质的增加以及Zeta电位负电性的降低促使生物膜疏水性和静电引力的升高,导致了生物膜后期的生长。同时,负荷不同会导致MAB形成过程和速率不同,负荷为0.157 m3/(m2∙d)时的生物膜厚度大于0.079 m3/(m2∙d)的厚度,分别为760 μm和360 μm。 反应器进水水质相同而负荷分别为SLR1(0.157 m3/(m2∙d))或SLR2(0.079 m3/(m2∙d))时,生物膜的底物分布、结构分层和传质分层不同。微电极测定结果表明,生物膜内部溶解氧(DO)浓度与膜的表面负荷(SLR)密切相关,随着SLR的增加,生物膜从内向外形成好氧区、缺氧区和厌氧区。SLR1时生物膜孔隙率和传质系数均高于SLR2的情况,生物膜深度方向上AOB菌的丰度也相应的产生梯度变化。生物膜的结构参数和传质特性间互相联系,SLR1和SLR2时生物膜孔隙率与菌群梯度、DO分布以及传质系数之间的皮尔森系数分别为0.75、0.68和0.82或0.96、0.56和0.95,孔隙率可用于表征生物膜内部的传质情况。不同的COD/N比和COD或氨氮负荷下,微电极和FISH结果表明,底物(NH4+-N、NO3--N、NO2--N和DO)和菌种在生物膜深度方向上形成了分层结构,可以实现单一MAB内的同时硝化反硝化。合适的好氧区比例为0.6-0.87之间,适宜的负荷是形成菌种分层的条件。COD负荷高于23.6 g/(m2.d)时在MAB内能形成好氧/缺氧分区结构。 错流速度会影响MABR反应器内部和生物膜附近的流场,总传质阻力是处理效果的控制因素。Fluent模拟表明错流速度增加时,膜丝周围的流速增加,导致边界层厚度降低,传质外部阻力下降。生物膜EPS的含量、分形维数等增加,表现为生物膜密度增加,内部传质阻力增加。流速为4.95 cm/s时,总传质阻力最小,对应的TN去除效果也最好。
英文摘要:       Landfill leachate is difficult to deal with, and it is often cotreated with urban sewage in some towns with the aim to cost saving. However, COD to NH4+-N ratio of the combined wastewater is often low after landfill leachate and domestic sewage are mixed, which leads to excessive nitrogen in the effluent. Membrane-aerated biofilm reactor (MABR) is a technology in which a gas-permeable membrane is used as both the carrier for biofilm growth and the diffuser for oxygen supply to the biofilm, and its biofilm has unique counter-diffusive structure compared to conventional biofilms since oxygen is supplied from the base of the biofilm and organic carbon comes from the bulk liquid. This property leads to stratified microbial community structure and spatial substrate organization across the biofilm depth, which can concurrently provide favorable microenvironment for both nitrification and denitrification and be suitable for treating the sewage of low COD to nitrogen ratio. But the quantitative nitrogen removal performance of MABRs are unclear, especially in the situation that variation of operating conditions will make a substantially difference in the microbial structure and substrate distribution. Furthermore, the MABR applied to co-treat landfill leachate with domestic sewage has been not reported. Therefore, the performance of MABR and the MAB characteristics treating the mixed wastewater were investigated under the different operating conditions with the aim to gain the optimized running conditions and quantified characteristics of membrane aerated biofilms, and to provide the scientific basis for the process control. The effect of fiber space and length and oxygen pressure on TN remove rate was studied in order to optimize the membrane module. The optimized value were 4.7 mm and 70 cm respectively.The membrane resistance increased with the increment of gas supply pressure. Thus air pressure should be controlled appropriately to avoid high energy consumption. The key of the MABR was the adhesion and growth of biofilm on the membrane surface. MAB characteristics and the governing factor in its different growth stages were studied in this paper. The growth process was in accordance with traditional S form law. In the early stage, the adhesion of polysaccharides to the membrane played an important role in biofilm formation. With the MAB development, the content of hydrophobic substances such as protein increased and the Zeta potential decreased, which lead to the increment of flocculability and electric attraction, and then the further growth of the MAB. Biofilm structure, effective oxygen diffusivity variations within the biofilms, and stratification of bacterial community were studied under different surface loading rate s (SLRs) by using DO microelectrode, fluorescence in situ hybridization (FISH) and the software of Image Structure Analyzer-2 (ISA-2). Then correlations between these properties were analyzed. Experimental results showed that two SLRs produced substantially different biofilm characteristics versus the biofilm depth. The biofilm under SLR1 formed the stratification structure to gain good total-nitrogen removal. Furthermore, the inflexions in spatial distributions of porosities, the AOB fraction, and DO distribution and diffusion coefficient overlapped at the oxic/anoxic boundary. And DO concentration affected greatly on the distribution of AOB and they were linearly related. This study suggested that SLR played an important role in affecting biofilm characteristics of which every aspect was associated with each other. Moreover, the loading rate affected DO distribution of in a MAB, and then affected the microbial community structure. And COD and NH4+-N concentrations within a MAB, which had a significant influence on the abundance of microbial community, were greatly related to influent organic substance compositions of a MABR. The nitrogen removal of a MAB was consistent with the abundance of microbial community, and the loading rate, COD/N ratio and influent composition had comprehensive effect on it. The appropriate proportion of aerobic zone was 0.6-0.87 and SLR was 23.6 g/(m2.d). The operating factor of the flow velocity was also studied because it had great influence on the biofilm characteristics and the mass transfer. The quantitative relationship between the flow velocity and the resultant biofilm characteristics and the external and internal mass transfer resistances was developed through the combination of CFD, DO microelectrode, CLSM, Biot number and so on. On one hand, the flow regime under the flow velocity of 4.95 cm/s was more homogenous than the other two. And on the other hand, the higher the flow velocity could induce the less the boundary thickness, the more smoothness the biofilm surface and the greater the biofilm density. Moreover, CLSM images of EPS distribution showed that the content of proteins increased corresponding to the increment of the flow velocities with the higher of fractal dimension, which indicated that the biofilm became more compact under the greater flow velocity. Based on the above results, the total mass transfer resistances were calculated and compared among the three flow velocities and the optimal value was 4.95 cm/s. And the best treatment efficiency was gained under the same value as well.
内容类型: 学位论文
URI标识: http://ir.rcees.ac.cn/handle/311016/35072
Appears in Collections:水污染控制技术研究室_学位论文

Files in This Item:
File Name/ File Size Content Type Version Access License
MABR处理城市污水与垃圾渗滤液混合污水生物膜特性研究.pdf(3570KB)学位论文--限制开放 联系获取全文

Recommended Citation:
袁栋栋. MABR处理城市污水与垃圾渗滤液混合污水生物膜特性研究[D]. 北京. 中国科学院研究生院. 2011.
Service
Recommend this item
Sava as my favorate item
Show this item's statistics
Export Endnote File
Google Scholar
Similar articles in Google Scholar
[袁栋栋]'s Articles
CSDL cross search
Similar articles in CSDL Cross Search
[袁栋栋]‘s Articles
Related Copyright Policies
Null
Social Bookmarking
Add to CiteULike Add to Connotea Add to Del.icio.us Add to Digg Add to Reddit
所有评论 (0)
暂无评论
 
评注功能仅针对注册用户开放,请您登录
您对该条目有什么异议,请填写以下表单,管理员会尽快联系您。
内 容:
Email:  *
单位:
验证码:   刷新
您在IR的使用过程中有什么好的想法或者建议可以反馈给我们。
标 题:
 *
内 容:
Email:  *
验证码:   刷新

Items in IR are protected by copyright, with all rights reserved, unless otherwise indicated.

 

 

Valid XHTML 1.0!
Copyright © 2007-2018  中国科学院生态环境研究中心 - Feedback
Powered by CSpace