印染废水开题报告教材

1、本科毕业设计 （ 论文） 开题报告题目： 蜡印废水处理工艺技术课 题 类 型： 设计 实验研究 论文 学 生姓 名：许轩学号：31204060213专 业班 级：环境工程 122学 院：生化学院指 导 教 师： 魏翔开 题 时 间： 2016 年 3 月 4 号2016 年 3 月 15 日一、本课题的研究内容及意义 在纺织工业中会产生各种废水，其中以印染废水污染较为严重，其排放量约 占工业废水总量的 1/10 ，我国每年约有 67亿t 印染废水排入水环境中，是当前 最主要的水体污染源之一， 因此印染废水的综合治理已成为一个迫切需要解决的 问题。印染废水主要由退浆废水、煮练废水、漂白废水、丝光

2、废水、染色废水和 印花废水等组成，其特点是成分复杂，色度高，有毒物质多，属于含有一定量有 毒物质的有机废水， 主要含有残留染料、 印染助剂、 酸碱调节剂和一些重金属离 子，化学需氧量 COD较高，而生化需氧量 BOD5相对较小，可生化性差，是当前国 内外公认的较难处理的工业废水之一 1 。印染废水含大量的有机污染物，排入水 体将消耗溶解氧， 破坏水生态平衡， 危及鱼类和其它水生生物的生存。 沉于水底 的有机物，会因为氧分解而产生硫化氢等有害气体， 恶化环境。 印染废水的色泽 深，严重影响受纳水体外观， 用一般的生化法难以去除， 有色水体还会影响日光 的透射，不利于水生物的生长。 水是一种易受污

3、染而可以再生的自然资源。 为了 使这个自然水循环能够持续地为人类服务， 水在使用后回归自然界前， 必须进行 废水的再生处理， 使水质达到自然界自净能力的承受水平， 恢复其作为自然资源 的属性。 2二、蜡印废水处理工艺的研究现状和发展趋势（文献综述）2.1 研究现状20 世纪 90年代以来，我国经济高速发展，人民生活水平不断提高，但环境 污染问题并未得到有效控制， 在有些地区反而呈现加重的趋势。 据报道， 我国每 年污水的排放量约为 3. 9 1010t ，其中工业废水占 51%，并以 1%的速率逐年递 增3 。随着工业化进程的不断深入，全球性环境污染日益破坏着地球生物圈几亿 年来所形成的生态平

4、衡， 并对人类自身的生存环境造成了严重威胁。 由于逐年加 重的环境压力， 世界各国纷纷制定各自的环保法律、 法规和采取不同的措施， 我 国政府对环境问题也高度重视， 并向国际社会全球性环境保护公约做出了自己的 承诺。我国是纺织印染的第一大国， 而纺织印染行业又是工业废水的大户， 故有 此而造成的生态破坏及经济损失是不可估量的， 因而要实现印染行业的可持续发 展，必须首先解决印染行业的污染问题。 42.2 发展趋势目前印染废水的处理逐渐向膜法和其它处理技术相结合发展。 工程师与研究 人员不断开始研制新的超滤膜， 改善超滤膜的材质， 孔径大小等方面性能， 主要 为了降低膜的制作成本， 提高过滤效能

5、。 然而膜法仍然具有它的缺点， 只采用透 过液反冲洗的清洗方法已不能保持膜的通量稳定， 需采用药剂清洗， 膜的污染比 较严重，这一问题尚未很好的解决。 而且，国内目前还未开发出高质量的超滤膜 装置，需从国外引进成套的工艺设备，价格必然不菲。因此如何降低成本，保持 膜的稳定性能是未来研究的重点 5 。2.3 印染废水的处理方法吸附法吸附法是应用较多的物理处理方法。 该方法采用多孔状物质的粉末或颗粒与 印染废水混合，或使废水通过由颗粒状物质组成的滤床 , 使废水中染料、助剂等 污染物质吸附于多孔物质表面等而除去。 吸附技术特别适合低浓度印染废水的深 度处理,在工艺上具有投资小 ,方法简便易行 ,成

6、本较低的优点。吸附法在实际应 用过程中应重点考虑吸附剂的选择、吸附剂的再生以及废吸附剂的后处理 , 以提 高处理效果 , 降低处理成本和减少二次污染。常用的吸附剂主要有活性炭、离子 交换纤维、炉灰、各种天然矿物、工业废料及天然植物废料等，一些合成无机吸 附剂也被应用于处理印染废水，如含有 SiO2 的复合氧化物、合成 Mg(OH2) 吸附 剂等。由于印染废水的水质复杂， 单一的吸附处理无法达到理想的处理效果， 实 际应用中需进一步开发适用性较广的吸附剂同时必须开发吸附技术与其它技术 的组合工艺 6,7 。化学氧化法化学氧化是目前研究较为成熟的方法。 借助氧化还原作用破坏染料的共轭体 系或发色基

7、团是印染脱色处理的有效方法。 除常规的氯氧化法外， 国内外研究重 点主要集中在臭氧化、超声波氧化、过氧化氢氧化、电解氧化和光氧化方面。氧 化剂一般采用 Fenton 试剂、臭氧、氯气、次氯酸钠等。按氧化剂的不同，可将 化学氧化分为： 臭氧化法和芬顿试剂氧化法。 氧化法是一种优良的印染废水脱色 方法，但如果氧化程度不足， 染料分子的发色基团可能被破坏而脱色， 但其中的 COD仍未除尽；若将染料分子充分氧化，能量、药剂量消耗可能会过大，成本太 高。臭氧化法不产生污泥和二次污染， 但是处理成本高， 不适合大流量废水的处 理，而且 COD去除率低。 通常很少采用单一的臭氧法处理印染废水， 而是将它与

8、其它方法相结合， 彼此互补达到最佳的废水处理效果。 所以氧化法一般用于氧化 絮凝或絮凝氧化工艺 8,9 。2.3.3 生物处理法生物处理法是利用微生物酶来氧化或还原有机物分子， 通过一系列氧化、 还 原、水解、 化合等生命活动， 最终将废水中有机物降解成简单无机物或转化为各 种营养物及原生质。 生物法具有运行成本低、 处理效果稳定等优点， 在印染废水 处理中得到了较为广泛的应用。 常用的印染废水生物处理方法有厌氧法、 好氧法、 厌氧好氧组合法。好氧生物处理是在有氧条件下，利用好氧微生物的作用来去除印染废水中 的有机物。活性污泥法、生物滤池、生物转盘、氧化沟、生物塘和膜生物反应 (MBR) 等都

9、属于废水好氧生物处理法。强化生物铁活性污泥法， 通过采取向曝气池中投加氢氧化铁， 延长难降解物质的 停留时间等措施， 能大幅提高曝气池的活性污泥浓度和抗冲击负荷能力， 降低污 泥负荷，使单位数量菌团承担的有机物降解量减少， 使菌胶团表面的有机物得到 及时! 充分的氧化降解，从而提高系统的脱色率和 COD去除率。生物膜法是将微生物细胞固定在填料上， 微生物附着于填料上生长、 繁殖， 在其上形成膜状生物污泥。 与常规活性污泥法相比， 生物膜法具有生物体体积浓 度大，存活世代长， 微生物种类繁多等优点， 尤其适合于特种菌在印染废水体系 中的投加使用。常用的生物膜法包括 生物转盘、生物接触氧化法、生物

10、滤池。 厌氧生物法不仅可用于处理高浓度有机废水， 也可用于处理中、低浓度有机废水， 对染料中的偶氮基、 蒽醌基和三苯甲烷基均可降解， 但还不能完全分解一些活性 染料的中间体，如致癌的芳香胺等。 由于厌氧生物法的出水水质往往达不到排 放标准，因而单纯使用厌氧生物法的处理工艺较少， 通常与好氧生物法串联使用。 厌氧好氧组合处理工艺， 能在一定程度上弥补好氧生物处理工艺的不足。 难降解 染料分子及其助剂在厌氧菌的作用下水解 ! 酸化而分解成小分子有机物，接着被 好氧菌分解成无机小分子。 通常厌氧段采用 USB反应器，好氧段目前大多采用生 物接触氧化法。间歇曝气活性污泥 SBR工艺，采用间歇运行方式，

11、废水间歇地进 入处理系统并间歇地排出， 充分利用兼性菌的作用， 在同一反应器内程序地进行 缺氧- 厌氧- 好氧过程，抗负荷与毒物冲击能力显著增强，可实现高进水浓度 ! 高容积负荷和高有机物去除率，在处理高浓度印染废水方面独具特色而且对氮、 磷、硫的脱除效果亦十分显著 9.10 。2.3.4 光化学氧化法光催化氧化法是利用某些物质在紫外光的作用下产生自由基 , 氧化染料分子 而实现脱色。 TiO2 光催化氧化法在 PH值为 3-11 时产生 O和OH，使染料分子迅 速分解而获得很好的脱色效果。铁羧酸配合物光催化氧化法，以铁-草酸、铁 -柠檬酸或铁 - 丁二酸络合物作催化剂，在紫外光照射下，光解生

12、成烷基、羟基等 多种自由基， 使印染废水氧化脱色。 光催化氧化技术以其具有常温常压操作、 有 害物质分解彻底、 能耗及材料消耗低、 无二次污染等优点， 具有良好的应用前景 11,12。2.3.5 膜分离技术膜分离技术处理印染废水是通过对废水中的污染物的分离、 浓缩、回收而达 到废水处理目的。具有不产生二次污染、能耗低、可循环使用、废水可直接回用 等特点。膜分离技术虽然具有如此多的优点， 但也存在着尚待解决的问题， 如膜 污染、膜通量、膜清洗、以及膜材质的抗酸碱、耐腐蚀性等问题，所以，现阶段 运用单一的膜分离技术处理印染废水， 回收纯净染料， 还存在着技术经济等一系 列问题。现在膜处理技术主要有

13、超滤膜， 纳米滤膜和反渗透膜。 膜处理对印染废 水中的无机盐和 COD都有很好的去除作用 13 。2.3.6 高能物理法线辐照下产生一系列高活性粒子 , 有害物质得到降解 . 技术的特点是有机物 的去除率高 ,备占地面积小 ,作简便,由于用来产生高能粒子的设备昂贵 ,术要求 高,耗大,量利用率低 ,真正投入实际应用还有大量的问题需要解决 14。三、课题研究方案及工作计划印染废水处理工艺中的厌氧水解处理工艺是利用产甲烷菌与水解产酸菌生 长速度不同，在反应器中以水流动的淘洗作用，使甲烷菌在反应器中难以繁殖， 将厌氧处理控制在反应时间短的第一阶段，即在大量水解细菌、产酸菌作用下， 将不溶性有机物水解

14、为可溶性有机物， 将难生物降解的大分子物质转化为易生物 降解的小分子物质。 将厌氧水解处理作为各种生化处理的预处理， 可提高污水生 化性能， 降低后续生物处理的负荷， 因而被广泛运用在难生物降解的化工、 造纸 及有机物浓度高的食品废水处理中。 此外，厌氧水解处理亦可用于城市污水处理 厂，以水解池代替初沉池， 减少后续处理构筑物曝气池的停留时间， 从而降低工 程投资。本课题采用厌氧水解处理， 蜡染印染废水的处理工艺包括以下步骤： 将污 水收集至调节池；在调节池内设置曝气装置，调节 PH值至 89；在平流沉 淀池前分别投加聚合氯化铵（ PAC）和聚丙烯酰胺（ PAM）；在厌氧池内进行厌 氧处理，

15、并外加间歇式内循环回流； 在接触氧化池内进行供氧； 在沉淀池内 进行泥水分离； 将污泥浓缩池的污泥压缩采用水压式隔膜压滤机过滤， 形成泥 饼15 。如图：工作计划：（1）、第 12 周：查阅相关资料，了解研究内容及现状，制订研究方案，拟订 初步的工作计划；（ 2）、第 34 周：开题，完善研究方案；（3）、第 514 周：查阅相关资料和文献，进行相关图纸的绘制及计算；（ 4）、第 1517 周：编写毕业论文（5）、第 18 周：毕业论文答辩四、主要参考文献1 孙政.印染废水水质特征及生物处理技术综述 .煤矿现代化 .2007 年第一期2 戴日成，张统，郭茜，曹健舞，蒋用印染废水水质特征及处理技

16、术综述 . 工业 给排水3 耿云波，刘永红，赵鹏飞印染废水处理技术的应用及研究进展，工业用水与 排水 Vo1.41 No.4 Aug.20104 周瑶，郭超，杨波，前夕印染废水处理工艺，黑龙江环境通报 Vo1.34 No.2 Jun.20105 肖冬雪，王兆慧，郭耀光，柳建设印染废水的处理方法及其发展趋势的探讨 CHINA POPULATION,RESOUCES AND ENVIRONMENT Vo1.21 20116 赵宜江,张艳,嵇鸣,等.印染废水吸附脱色技术的研究进展 j .水处理技 术,2000,26（6）:315-3197 张建英,梁缘东,陈曙光,等,染色废水吸附混凝效应研究 j ,

17、环境污染与防 治,1998,20（3）:9-128 张艳,赵宜江,嵇鸣,等.印染废水物理化学脱色方法的研究进展 j .水处理技 术,2001,27（6）:311-3149 郑冀鲁,范娟,阮复昌,印染废水脱色技术与理论技术 j .环境污染治理技术与 设备,2000,1（5）:29-3510 魏建斌, 付永胜, 朱杰,等.印染废水生物脱色研究现状及展望 j. 污染防治技 术,2003,16（4）:87-9111 刘长春, 张峰, 毕学军.TiO 2光催化氧化技术在废水处理中的应用 j. 污染防治 技术,2003,16(4):111-11412 罗凡,吴峰, 邓南圣, 等, 铁()羧酸配合物对水溶性

18、染料的光化学脱色动力 学的比较研究 j. 环境科学与技术， 1998(2):1-413 刘梅红，纳滤膜技术处理印染废水实验研究 j 水处理技术， 2002,28(1):42-4414 李胜利，李劲.用高压脉冲放点等离子体处理印染废水的研究 j . 中国环境科 学， 1996,16(1):73-7615 发明专利. 孔建成.一种蜡印废水的处理工艺 :中国,CN 104163549 A. 2014-081016 Mustafa Isik Delia Teresa Sponza,Anaerobic/aerobic treatment of a simulated textile wastewater

19、,ScienceDirect,Separation and Purifcation Technology 60(2008)64-721718 .Biotechnology & Bioprocess Enfineering Feb2014, Vol. 19 Issue 1, p191-200. 10p.19 Wool Textile Journalapr2015, Vol. 43 Issue 4, p41-44. 4p.20 Journal of the Serbian Chemical Society.2015, Vol. 80 Issue 1,p115-125. 11p.外文文献翻译英文部分

20、Abstract In this study, the bacterial dynamics and structure compositions in the two-stage biological process of a full-scale printing and dyeing wastewater (PDW) treatment system were traced and analyzed by terminal restriction fragment length polymorphism (T-RFLP) and 454 pyrosequencing techniques

21、. T-RFLP analysis showed that the microbial communities experienced significant variation in the process of seed sludge adaptation to the PDWe nvironments and were in constant evolution during the whole running period of the system, despite the constant CODa nd color removal effects. Pyrosequencing

22、results indicated that the two-stage biological system harbored rather diverse bacteria, with Proteobacteria being the predominant phylum during the steady running period, although its microbial compositions differed. The firststage aerobic tank was dominated by -Proteobacteria (89.05% of Proteobact

23、eria), whereas in the second-stage aerobic tank, - and -Proteobacteria,besides16 -Proteobacteria, were the dominant bacterial populations.1. IntroductionPrinting and dyeing wastewater (PDW) has long been considered as an important and difficult-to-treat effluent due to its toxic, frequently changing

24、, and bio-recalcitrant components such as dyes and dyeing additives, low ratio of BOD5/COD (around 20%), and high pH value (10 13). The current PDW treatment employed in China is a combination of physical-chemical and biological processes, in which various biological methods play principal roles and

25、 are capable of removing 40 50% of COD and 50 60% of color. However, during system startup or system running period, important problems such as reduced oncentration of activated sludge, sludge expansion, and formation of large amounts of foam frequently occur, resulting in a serious decrease in trea

26、tment efficiency or even collapse of the system. Bacteria are the dominant population in the activated sludge, and it is hypothesized that the dominant microorganisms play the most important roles in each stage of the system. Therefore, determination of the bacterial compositions corresponding to th

27、e stages of the system will be helpful for understanding and solving the above-mentioned problems. In recent years, various molecular biological techniques have been used for the analysis of microbial communities in various wastewater treatment systems. However, most of the previous studies had focu

28、sed more on the relationship between functional stability and microbial community stability or the effects of running parameters on microbial compositions under the conditions of lab-scale bioreactors normally fed with synthetic wastewater. Only a few reports had examined fullscale industrial wastew

29、ater treatment systems, and even fewer had analyzed PDWtr eatment systems. Due to the frequently changing characteristics and complex compositions of PDW, understanding of the relationship between the microbial community dynamics and startup and stable running of the system is important for the desi

30、gn and operation of a PDWt reatment system. The molecular biological techniques have some limitations in completely revealing the microbial compositions or tracking the evolution process of the microbial community in a wastewater treatment system. In our previous study on the dynamic changes in the

31、microbial community in the PDW treatment system, PCR-DGGE (denaturing gradient gel electrophoresis) method was used. However, with the development of sequencing techniques, it has been noted that DGGE indicates only a minor part of the microbial population in an environment. Furthermore, some recent

32、ly developed techniques such as terminal restriction fragment length polymorphisms (T-RFLP), real-time PCR, 454 pyrosequencing, etc., provide a possibility to obtain dynamic information or more accurate compositions of a microbial community. Therefore, in this study, T-RFLP and 454 pyrosequencing me

33、thods were used to trace and reveal the evolution processes of bacteria in a full-scalePDW biologicaltreatment system during the establishment and commissioning periods. The results of this studyare expected to form the basis of further researchon the functions of the microbial populations in wastew

34、ater treatment systems17 .2. Materials and Methods2.1. PDW treatment system and wastewater characteristicsThe PDW treatment system was established by Xinxiang Lianda Printing & Dyeing Co., Ltd (Xinxiang, China) in October 2009 for treating 1,000 tons of effluent everyday. The system consisted of aco

35、agulation precipitation unit and a two-stage biological treatment process, including process 1 (an anaerobic hydrolytic and acidification unit (H1), an aerobic activated sludge treatment unit (O1), and a settling tank 1) and process 2 (an anaerobic hydrolytic and acidification unit (H2), an aerobic

36、bio-contact oxidation unit (O2), and a settling tank 2), as shown in Supplementary Fig. 1. The seed sludge was collected from a municipal wastewater treatment plant and was first inoculated into O1 at the beginning of the system startup. H2 was started 23 days after O1 operation by inoculating a par

37、t of sludge from the settling tank 1 and a part of sludge from the same municipal wastewater treatment plant as that used for inoculating O1.The characteristics of PDW and the performance of the biological wastewater treatment system were continuously monitored for more than 6 months. The concentrat

38、ions of COD, BOD5, colority, suspended solids (SS), total nitrogen (TN), total phosphates (TP), NH4+ -N, and pH were determined using standard methods 12. The characteristics of the wastewater are shown in Supplementary Table 1.2.2. Sludge samplesSludge samples were collected from the above-mentione

39、d biological treatment units at different periods of operation, i.e., seed sludge (day 1 and day 23 for O1 and H2, respectively), after system startup (day 23 for both O1 and H1; day 29 for O2), and in the middle of operation (day 29 and day 185 for O1 and H1, respectively; day 185 for both O2 and H

40、2).The samples from different treatment tanks were centrifuged at 12,000 rpm for 10 min at 4o C. The pellets were washed twice (each were centrifuged for 10 min at 12,000 rpm) with phosphate buffer (pH 7) and stored at-20 for molecular analysis.2.3. DNA extractionThe total DNA was extracted from the

41、 sludge pellets by using the cetyltrimethylammonium bromide (CTAB) method 13. The yield and fragmentation of the crude or purified DNAw ere determined by agarose gel electrophoresis (1% w/v agarose) and UV visualization after ethidium bromide (EB) staining. The purified DNA was then stored at- 20 fo

42、rT-RFLP and pyrosequencing.2.4. PCR amplification of 16S rRNA genes for T-RFLPFor T-RFLP analysis, labeled forward primer 63F (labeled with 6-FAM( blue) (5-CAG GCC TAA CAC ATG CAA GTC-3) and unlabeled reverse primer 1389R (5-ACG GGCG GTG TGT ACA AG-3) were used 10. The PCRw as conducted under the fo

43、llowing conditions: 95for 5 min, followed by 30 cycles of 94for 1 min, 55 for 1 min, and 72 for 2 min, and a final extension at72 for 10 min. The 1.3-kb 16S rRNA gene fragments obtained by PCR were purified from 1% agarose gels with a UNIQ10 column DNA purification kit (Sangon, China) according to t

44、he manufacturer s recommendations 18.2.5. T-RFLP analysisThe labeled PCR products (10L) were digested at 37 for 16 h withAluI(AG/CT) and MspI(C/CGG), respectively. The reaction mixtures contained 2 L of 10 restriction enzyme buffer, 10 L of template, 1 L of AluI or MspI, and ultrapure water to a fin

45、al volume of 20L. Thereactions were inactivated by incubation at 80 for 20 min for AluI and 65 for 20 min for MspI. The digested DNAwas precipitated with 75Lof 95% ice-cold ethanol and 3 L of 3 M sodium acetate at-20 for 12h, followed by spinning at 4,000 rpm and 4 in a micro centrifuge for60 min. T

46、he DNA pellet was washed with 70% ice-cold ethanol, dried, and suspended in 9 L of sterile water foranalysis 14. The TRFs wereanalyzed by Shanghai Gene Core Bio-Technologies Co., Ltd (Shanghai, China). The T-RFLP profiles were aligned by inspecting the electrophore to grams and by manual grouping of

47、 the peaks into categories. The presence or absence of peaks in the T-RFLP profiles was the basis for the construction of a pair wise Dice distance matrix for use in a non-parametric multidimensional scaling (NM-MDS)a nalysis utilizing the PC-Ord 5.0 software.2.6. High-throughout 454 pyrosequencingT

48、he composition of the PCRp roducts of the V3 region of 16S rRNA gene was determined by 454 pyrosequencing by BGI (Shenzhen, China). The bacterial universal primer pair,27F (5-AGAGTTTGATCCTGGCTCAG-3a) nd 534R (5-ATTACCGCGGCTGCTGG-3), was used 15, and the samples used in this study were individually b

49、arcoded to enable multiplex sequencing. Following pyrosequencing, Python scripts were written to: (1) remove sequences containing more than one ambiguous base; (2) check the completeness of the barcodes and the adapter; and (3) remove sequences shorter than 150 bp 16. The effective sequences were an

50、alyzed by using RDP(Ribosomal Database Project, ) to construct the distance matrices, assign sequences to operational taxonomic units (OTUs, 97%s imilarity),and calculate Chao1 richness estimators 17. Thesequences of the dominant OTUs were extracted to run BLAST and search relatives against “nr” dat

51、abase using the Internet automatically (). A phylogenetic tree was constructed using the neighbor joining method in MEGA version 4.1 using 1,000 bootstrap replications. The archaeon Methanobacterium formicicum was used as an out-group 19 .3. Results and Discussion3.1. Performance of the PDW treatmen

52、t systemThe COD and color of the PDW were 646 5,056 mg/L and 80 650 dilutes, respectively. After coagulation and precipitation by using FeSO4 and poly-aluminum chloride (PAC), the COD and color reduced to 417 3,750 mg/L and 40 550 dilutes, with an average removal rate of 43.9 and 38.5%, respectively

53、. At the same time, the pH of the PDW was significantly reduced from 10.96 to 13.89 to around 8.50, which was necessary for the subsequent biological treatment. After the first-stage biological process, the CODa nd color were reduced to 174 902 mg/ L and 30 80 dilutes, with removal efficiencies of 2

54、5 83.4% and 25 89.1%, respectively. Green was the most difficult color to decolorize, whereas black and blue were easier to remove. Subsequently, for further treatment, the effluents from the first-stage biological treatment process were fed into the second-stage treatment process that was composedo

55、 f a hydrolysis tank and a biofilm contact oxidation tank. A further 10.8 53.9 and 25 66.7% reduction in COD and color were noted after this process, respectively, resulting in a final COD of 500 mg/L and color of 40 dilutes. After coagulation and the two steps of biological treatment, the total ave

56、rage removal rates of COD and color reached 85%, with the final color of the effluents satisfying the local discharge standards ( 50 dilutes). However, a residual CODo f 146 492 mg/L was noted, which could be resolved through further treatment by using Fenton oxidation method.3.2. Dynamic changes in

57、 the bacterial community structure with system operationThe dynamic variation in the bacterial community was traced by using T-RFLP method (as shown in Supplementary Figs. 2 and 3). The T-RFLP profiles indicated diverse and fluctuating dominant bacterial populations in the collected samples. Analysi

58、s of Shannon diversity index on the T-RFLP profiles indicated that different treatment tanks of the system harbored diverse bacteria, with H = 0.83 1.20 and 0.71 1.07 for AluI and MspI restriction enzyme digestion maps, respectively. Samples from the first biological treatment process (O1 and H1) showed higher bacterial diversity than those from the second one (O2 and H2). The dominant peaks changed both in height and peak time among the seed sludge samples and steady running stage samples,