【作者】 王建芳；

【导师】 赵庆良；

【作者基本信息】 哈尔滨工业大学 ， 环境工程， 2008， 博士

【摘要】 以活性污泥和生物膜为代表的污水生物处理以高效低耗的突出优点广泛应用于城市污水和工业废水处理。然而,产生大量剩余污泥以及高昂的污泥处理费用已成为污水生物处理技术最大弊端之一。因此,如何从根本上解决剩余污泥问题已成为当今环境工程界面临的挑战。在污水处理过程中减少剩余污泥排放,从源头上降低剩余污泥产量的各种污泥减量技术已成为废水生物处理研究的热点和发展方向。具有代表性的好氧-沉淀-厌氧(OSA)工艺在传统活性污泥工艺污泥回流段增加污泥厌氧环节,不需要添加任何化学药剂和贵重设备,有利于降低运行和投资成本,符合可持续污水处理模式,具有良好的工业化应用前景。本论文系统研究了好氧-沉淀-厌氧工艺污水处理效能和污泥减量效果以及影响因素,探索了工艺污泥减量机制,首次利用变性梯度凝胶电泳(DGGE)技术和荧光原位(FISH)技术分析了OSA工艺微生物种群特征、多样性以及运行条件变化对优势种群更替的影响。开发了具有内源反硝化除磷功能的污泥减量新工艺,探讨了内源反硝化除磷污泥减量新工艺污水处理效能和污泥减量效果以及相关的影响因子,着重对工艺反硝化除磷效能和特征进行了分析和研究,并利用DGGE和FISH技术从微生物生态学角度探讨了微生物种群特征与工艺处理效能间的关系。以传统活性污泥(CAS)工艺为参照,在分析探讨厌氧-沉淀-好氧(OSA)工艺污泥减量和污水处理效能以及相关影响因子的基础上,着重研究了OSA工艺污泥减量的内在控制机制。研究结果表明,由于微生物维持代谢和内源代谢增加引起的污泥衰减和慢速生长微生物是OSA工艺污泥减量的主要原因,其中大约2/3的污泥减量是由污泥衰减引起的,慢速生长微生物对OSA工艺污泥减量的贡献为23%左右;10%左右污泥减量是由能量解偶联机制引起的。利用DGGE和FISH技术对OSA工艺微生物种群多样性和群落特征进行研究分析,得到OSA工艺微生物种群多样性比CAS工艺更加丰富,增加有机负荷和废水水质复杂化都会使微生物种群多样性增加,但优势微生物群落基本不受影响,OSA工艺微生物群落结构相对稳定的这一特点决定了OSA工艺具有良好稳定的运行效能。从DGGE优势条带中分离到的11个优势菌与GenBank中已有微生种属比对发现,其中7个优势菌与GenBank统计的在反硝化污泥、EBPR污泥中出现的种属相似性非常高,表明OSA工艺中插入污泥厌氧池为内源反硝化菌和生物聚磷菌创造有利的生长条件。系统进化树分析结果表明,β-proteobacteria种属的微生物是OSA污泥系统的主要种群。开发了内源反硝化除磷污泥减量工艺,在好氧池有机负荷Ns约为0.87 kgCOD/kgMLSS·d,系统污泥回流比为25%,反硝化污泥回流比为35%的条件下稳定运行,污泥产量为4.78g/d,污泥产率为0.30gMLSS/gCOD,COD平均去除率为90%,NH4+-N、TN的去除率分别稳定在86%和84%左右,TP去除率达到80%左右。内源反硝化除磷工艺中缺氧反硝化聚污泥约占总聚磷污泥的35%~44%。提高SRT,可提高生物吸磷效率,增加污泥中磷含量,这一定程度上缓解了剩余污泥排放量和TP去除率之间的矛盾。利用DGGE技术,对代表性优势条带测序相似性比对,并构建系统进化树,分析内源反硝化除磷工艺微生物群落特征。内源反硝化除磷工艺中的微生物主要由α-proteobacteria、β-proteobacteria、γ-proteobacteria、CFB-group bacteria、low G+C gram-positive bacteria五大菌群构成,其中β-proteobacteria种属的微生物在整个工艺微生物菌群数量中占绝对优势,达到48%左右。以DAPI为背景,用PAOmix探针FISH杂交证实了聚磷菌在内源反硝化除磷工艺缺氧污泥和厌氧污泥中都占有优势,分别占微生物总量的40%和33%左右。更多还原

【Abstract】 Activated sludge process and biofilm process with high efficiency and low cost have been applied worldwidely in municipal and industrial wastewater biological treatment. However, the most serious drawbacks of conventional biological wastewater treatment technology are tremendous production of excess sludge and the rising costs for final sludge treatment. So how to solve essentially the problem of excess sludge production is generating a real challenge in the field of environmental engineering technology. An ideal way to solve sludge-associated problems is to reduce sludge production in the wastewater treatment rather than the post-treatment of the sludge. The oxic-settling-anaerobic (OSA) process is a modified conventional activated sludge (CAS) process and reduces excess sludge by adding an anaerobic sludge tank in sludge return line. The OSA process is in accord with sustainable wastewater treatment model and reduces excess sludge by lower operational and investment cost for not adding any chemical and expensive equipments. The OSA process can be conveniently used to rebuild CAS process by inserting an anaerobic sludge tank in recycled sludge course, which is puzzled by heavy excess sludge production. So the Oxic-Settling-Anaerobic process provides a promising technique for industrial scale application.Performance of the OSA process has been systematically studied, including efficiency of wastewater treatment and sludge reduction, its affecting factors, and mechanism of minimization of excess sludge. For the first time, denaturing gradient gel electrophoresis (DGGE) and fluorescent in situ hybridization (FISH) were used to analyze microbial community characteristics, predominant community transformation by change of operational condition in OSA process. A new endogenous denitrifying phosphorus removal process with excess sludge reduction was developed. Efficiency of wastewater treatment and sludge reduction and its affecting factors were discussed. Efficiency and characteristics of denitrifying dephosphatation in the endogenous phosphorus removal process were studied emphatically. DGGE and FISH were used to investigate the relationship between microbial characteristics and treatment efficiency in various units of the endogenous denitrifying phosphorus removal process.In comparison with the CAS process, internal mechanism of excess sludge reduction was stressly discussed in the OSA process. As a result, the decisive cause of reducing excess sludge production is the increasing maintenance endogenous metabolism in the OSA process, which include sludge decay and anaerobic reactions with low sludge yield. It has been confirmed that sludge decay is the main cause in the OSA process, accounting for 66.7% of sludge reduction. These anaerobic reactions in sludge anaerobic tanks have lower sludge production than aerobic oxidation when equivalent SCOD is consumed, which may lead to approximately 23% of sludge reduction in the OSA process. There was energetic uncoupling in the OSA system since microorganisms were exposed to alternative anaerobic and aerobic environment, but which was a minimum factor, leading to about 10% of sludge reduction.The results of DG-DGGE profile and FISH analysis showed that there was more abundant microbial diversity in OSA sludge than that in CAS sludge. 11 predominant bands was excised from DG-DGGE and blasted in GenBank. Results showed that 7 clones represented by dominant bands in the DGGE gel of the OSA sludge were similar to bacteria isolated from denitrifying sludge and EBPR sludge. The finding explained that anaerobic sludge tank inserted in recycled sludge line provided a favorable environment for endogenous denitrifying bacteria and phosphorus removing bacteria. Phylogenetic tree of predominant DG-DGGE bacteria indicated thatβ-proteobacteria was the main community in the OSA sludge.A new endogenous denitrifying phosphorus removal process was developed. It was stably running when Ns was 0.87kgCOD/kgMLSS·d, ratios of system return sludge and denitrifying return sludge were 25% and 35%, respectively. Under the best conditions, sludge production was 4.78g/d and Yobs was 0.30gMLSS/gCOD while COD removal efficiency was about 90% and the percentage of NH4+-N, TN, TP was about 86%, 84% and 80%, respectively. Denitrifying phosphorus removal bacteria occupied 35%~44% of phosphorus accumulating bacteria in the endogenous denitrifying phosphorus removal process. Phosphorus content of sludge could be increased by extending SRT, which relaxed the contradiction between the production of excess sludge and TP removal efficiency.Analyzing and blasting the predominant bacteria represented by dominant bands in the DGGE gel of the endogenous denitrifying phosphorus removal process, it was detected that there were abundant microbial community.α-proteobacteria、β-proteobacteria、γ-proteobacteria、CFB-group bacteria、low G+C gram-positive bacteria were the main subclasses.β-proteobacteria was the predominant subclass, accounting for about 48%. FISH by PAOmix probe showed that phosphorus accumulating bacteria accounted for 40% of total bacteria in anoxic sludge and 33% of total bacteria in anaerobic sludge.更多还原