【作者】 王振；

【导师】 袁林江；

【作者基本信息】 西安建筑科技大学 ， 环境工程， 2009， 硕士

【摘要】 生物反硝化聚磷技术是目前污水处理研究领域的重点和热点。近年来,不断有研究发现,在实际的A²/O工艺运行中,缺氧池中的硝酸盐在进行反硝化的同时磷酸盐浓度也降低。即存在所谓的反硝化聚磷菌（DPB）,从而使聚磷和反硝化这2个独立的过程在DPB的参与下仅在缺氧环境下就可同时进行.反硝化除磷脱氮工艺与传统A²/O等工艺相比,不仅节省了对碳源的需要,使产生的剩余污泥量大幅度减少,且聚磷在缺氧条件下完成可节省曝气所需要的能源。基于反硝化聚磷理论,先后提出了A₂N和Dephanox等采用侧流硝化/厌氧/缺氧的新型生物脱氮除磷工艺,来实现污水氮磷的高效低耗去除。但是从现有的实践以及研究成果看,单纯的反硝化除磷速率都远较好氧除磷慢、除磷效率低,而且污泥在经历长期的厌氧/缺氧环境交替后,除磷效率都会下降,出现反硝化聚磷难以持久的现象,从而制约了反硝化聚磷在生物脱氮除磷工程的应用。在厌氧/缺氧交替的系统中,如何长久实现反硝化聚磷,维持反硝化聚磷的活性、保持反硝化聚磷菌的优势等问题值得研究。笔者利用2组厌氧/缺氧（A/A）SBR反应器,研究了系统中反硝化聚磷菌活性的变化,探讨了反硝化聚磷菌选择和富集的条件以及影响反硝化聚磷系统稳定运行的因素。为反硝化聚磷脱氮工艺设计以及厌氧/缺氧（A/A）环境下如何长久实现反硝化聚磷、维持反硝化聚磷菌的活性、保持反硝化聚磷菌的优势提供理论依据。试验结果表明:（1）采用2#反应器的两段进水方式运行对系统的反硝化除磷效果可以起到很好的强化作用,可达到快速富集DPB的目的。（2）优化系统运行条件有助于A/A（2#）系统快速富集DPB,系统pH值控制在7.0左右,COD:N:P为300:50:20时,反硝化除磷效果最佳,所用碳源最少,C、N、P的去除率均在95%以上。（3）在厌氧段供给高浓度磷、一段方式进水的A/A（1#）系统中,不能有效地富集DPB,系统的反硝化作用很强而反硝化聚磷效果较差。（4）在厌氧阶段,初始磷浓度越大对厌氧释磷的抑制也越大,使厌氧释磷量和厌氧释磷速率减小,而较低的初始磷浓度将有利于厌氧释磷。（5）厌氧段释磷受到抑制会使得系统中的COD的吸收也受到抑制,厌氧段释磷充分,COD才能充分吸收,有利于系统在缺氧段对磷的吸收。（6）对于1#系统,缺氧段COD浓度较高时,分批次投加硝酸盐可以获得比一次性投加硝酸盐更高的反硝化聚磷效率。（7）缺氧段COD浓度高会造成系统反硝化菌和反硝化聚磷菌的竞争,导致反硝化菌在有外碳源时抢先利用硝酸盐进行反硝化作用从而影响聚磷效果。缺氧段COD浓度低则有利于反硝化聚磷的效果。（8）经驯化富集DPB的A/A系统以一段进水方式（传统A/A运行方式）运行后,具有良好的反硝化除磷功能。提高系统的磷负荷有利于缺氧段聚磷。缺氧加磷运行方式要比厌氧加磷运行方式更好。（9）对于A₂N、Dephanox等反硝化聚磷工艺,在其初期运行时,可利用碳源与电子受体分开的两段进水的方法,以含硝酸盐含量较高的废水对其污泥进行预培养,待活性污泥中DPB得到富集后,再将其投入实践,可取得比较理想的反硝化聚磷效果。更多还原

【Abstract】 Biological denitrifying dephosphatation treatment was one of the focuses in the wastewater treatment area in recent years.It was found that nitrate was denitrifying with uptaking of phosphorus in anoxic tank of some practical A²/O processes.Denitrification and Dephosphatation that were mutually independent could perform simultaneously because of the participation of DPB in anoxic environment.Denitrifying dephosphatation process not only saved supply of carbon source,reduced surplus sludge volume to a large extent,but also save oxygen supply because of accomplishment of dephosphatation in anoxic environment.Lateral flow nitrifying/anaerobic/anoxic biological denitrifying phosphorus removal process,such as A₂N process and Dephanox process,was expected to realize the high efficient biological nutrient and phosphorus removal whichwas developed based on denitrifying dephosphatation.However,compared with conventional processes,process of denitrifying dephosphatation had slower rate of phosphorus removal and lower efficiency of phosphorus removal,Especially fact that phosphorus removal efficiency of sludge would become lower in A/A alternative environment had these bad influence on the application of this new process.How to realize denitrifying dephosphatation effectively for a long time,how to keep activity of DPB and to make DPB become dominant populations in the system of A/A alternative environment were worth to study.Two anaerobic/anoxic sequencing batch reactors（A/A SBR）were conducted to investigate the changes for the activity of DPB,the conditions for screening and enrichment of DPB and the factors which had influences on the stability of the system.Some useful theories had attained,such as how to design the process of denitrifying dephosphatation better,realize denitrifying dephosphatation effectively for a long time,keep activities of DPB and make DPB become dominant populations.The results showed that:（1） DPB could become dominant populations quickly in the 2# system in tow-time feeding mode which had important significance to enhancement of DPB.（2） It was helpful to make DPB become dominant populations quickly in the 2# A/A SBR when the conditions were optimized as that concentration of COD in influential of anaerobic stage,NO₃^--N and PO₄^3--P in influent of anoxic stage and pH value were 300 mg·L^-1,50 mg·L^-1,20 mg·L^-1 and 7.0 respectively.The reactor performed good denitrifying phosphorus removal.Carbon source needed was the lowest.The removal efficiency of C,N,P were all above 95%.（3） The enrichment of DPB couldn’t realize in the 1# system in one-time feeding mode with high PO₄^3--P concentration in influential in anaerobic stage.Denitrification performed well but denitrifying dephosphatation performed worse in the system.（4） The higher PO₄^3--P concentration in influential it was,the smaller amount of phosphorus released in anaerobic stage.Both phosphorus release and its release vilocity was reduced.It was implied that low concentration PO₄^3--P in influential was helpful for phosphorus release.（5） The suppression of phosphorus release in anaerobic stage would suppress the uptaking of COD at same time.The more amount of phosphorus released it was in anaerobic stage,the more amount of COD uptake had been gotten that was helpful for phosphorus uptake in anoxic stage.（6） Batch feed of nitrate got a better efficiency of denitrifying dephosphatation than one-time when COD concentration was high in anoxic stage in the 1# Reactor.（7） The high COD concentration in anoxic stage would lead to the competition between denitrifying bacteria and DPB.Nitrate would be reduced by denitrifying bacteria first when there existed carbon source.It was favorable for denitrifying dephosphatation that COD concentration was low in anoxic stage.（8） The SBR in which DPB was dominant in populations,still performed well in one-time feeding mode.It was favorable for phosphorus uptake when phosphorus load was increased.With the same concentration of phosphate,the phosphorus removal with adding the phosphate just before the beginning of anoxic stage proved to be better than that of directly increasing the phosphate concentration in the influent.（9） Activated sludge could be cultured and acclimated by feeding wastewater which had high concentration of nitrate in tow-time feeding mode in the initial operating stage of A₂N and Dephanox process.It would be put into practical operation after successful enrichment of DPB,and thereafter the efficiency of denitrifying dephosphatation would be better.更多还原