【作者】 刘洪波；

【导师】 夏四清；

【作者基本信息】 同济大学 ， 环境工程， 2007， 博士

【摘要】 水体富营养化是当今世界各国环境保护面临的共同问题，开发出高效低耗的除磷脱氮工艺可有效削减排放到水体中的氮、磷等营养物质，有效防止水体富营养化；低浓度城市污水由于碳源不足，同时除磷脱氮存在困难，更有必要寻求高效除磷脱氮技术。平行AN／AO（厌氧-缺氧／厌氧-好氧）工艺是在现有反硝化除磷工艺基础上提出的，主体是间隔成六个单元的矩形反应池，可根据进出水实际情况采用不同的组合方式，工艺简单、占地面积小、节省投资，能通过较长的厌氧水力停留时间和较大的缺氧池比例在系统中富集反硝化除磷菌，起到高效低耗除磷脱氮目的。工艺共有两种主要的工艺构型和三种主要的运行方式。试验对平行AN／AO工艺主要运行参数进行优化，并取得如下结论：①平行AN／AO工艺构型Ⅰ的优化结果如下：进水流量比（AN／AO）为12：8；SRT为15d；HRT取6h；混合液内回流比200％；污泥外回流比25％；在优化参数条件下，其出水COD、NH₃-N、TN、TP平均浓度可分别达到49.1 mgL^-1、0.4 mgL^-1，14.8 mgL^-1、0.8 mgL^-1，平均去除率分别为74％、99％、68％、83％。②构型Ⅱ主要工艺参数的优化结果如下：污泥外回流比100％、厌氧—缺氧内回流比100％、厌氧—缺氧内回流点为缺氧1池或缺氧3池。在SRT和HRT分别采用15d与6h，其它参数采用优化条件时，出水COD、NH₃-N、TN、TP平均浓度可分别达到45.9 mgL^-1、0.2 mgL^-1，12.7 mgL^-1、0.9 mgL^-1，平均去除率分别为74％、99％、74％、80％。在实际污水运行数据基础上，试验进一步以人工配水定量考察了平行AN／AO工艺中反硝化聚磷菌比例、缺氧除磷速率、聚磷菌“失活”、“复活”内在原因、碳源种类和初始总磷浓度等对好氧／缺氧除磷的作用机制等。并得到如下结论：①平行AN／AO工艺构型Ⅰ内污泥反硝化除磷菌活性约为好氧除磷菌活性的80％。②厌氧池残留硝酸盐浓度和缺氧池残留有机物浓度直接和聚磷菌的“失活”、“复活”现象相关。厌氧段残留NO₃-N浓度在2.3 mgL^-1左右即，缺氧初残留溶解性有机碳浓度在3.0 mgL^-1左右即可达到较为理想的除磷脱氮效果。③葡糖糖、乙酸、葡糖糖和乙酸混合物都可以作为好／缺氧除磷的有效碳源：同样条件下乙酸钠、乙酸钠和葡萄糖混合物、葡糖糖三种碳源的厌氧释磷量分别约为0.08 gP（gCOD）^-1、0.07 gP（gCOD）^-1、和0.04 gP（gCOD）^-1，混合碳源有可能产生低释磷量高效除磷现象。④乳酸碳源、葡糖糖和丙酸混合碳源缺氧除磷脱氮效率很低，且厌氧段没有释磷现象发生；丙酸单独做碳源时缺氧除磷体现出较为常规的厌氧释磷缺氧吸磷现象，但2h反应时间内除磷效率仅为68％。⑤以乙酸钠+丙酸、乙酸钠+乳酸、葡萄糖+乳酸为碳源时，厌氧段COD合成率在2h内分别达到77％、78％、76％；而乳酸碳源、葡萄糖+丙酸碳源，厌氧段COD合成不完全，2h内合成率仅为33％和36％；以丙酸为碳源时厌氧段COD合成率为51％。⑥相同进水TP浓度条件下，三种厌氧反应时间工况的除磷脱氮效率高低顺序为：厌氧6h工况〉厌氧2h工况〉厌氧4h工况；相同厌氧反应时间下，进水TP为12 mgL^-1工况的除磷脱氮率高于进水TP为6 mgL^-1工况。最后，采用聚合酶链式反应-梯度凝胶电泳（PCR-DGGE）克隆测序、脂肪酸甲酯（FAMEs）、醌指纹法等互补手段分析平行AN／AO工艺的种群结构，结果表明：①平行AN／AO工艺各反应池内微生物种群结构总体比较相似，但部分菌群在数量上会有较大差距，且厌氧池／缺氧池／好氧池都各自拥有少量特异性菌群。②平行AN／AO工艺系统中的优势微生物为放线菌如Rhodococcus sp．等，α-变形杆菌如Bdellovibrio sp．等，β-变形杆菌如Thiothrix sp．等；以氧气为电子受体时，试验测得的除磷菌种主要属于Dechloromonas sp．等；而以硝酸盐为电子受体时，试验测得的除磷菌种主要为Bdellovibrio sp．等细菌种属，并推定Bdellovibrio sp．等在厌氧—缺氧除磷过程中所特有的菌属可能为反硝化除磷菌；③在pH为6.5-8.5的范围内，试验条件下活性污泥中的除磷微生物群落结构变化不大。④平行AN／AO工艺厌氧池、缺氧池、好氧池内微生物种群结构在FAMEs、醌指纹和SEM电镜图上都存在一定的相似和相异性，可和PCR-DGGE群落分析结果互为补充。更多还原

【Abstract】 Eutrophication is a common environmental problem that the current world isencountering. Development of phosphorus and nitrogen removal processes with highefficiency and low power consumption can effectively reduce effluent nitrogen,phosphorus and other nutrients discharging to water bodies and thus slowdowneutrophication, if not eliminate it; Since carbon is normally insufficient forconventional BNR processes treating low strength municipal wastewater, it is urgentto develop high efficient carbon utilization BNR processes too.The parallel AN/AO （anaerobic-anoxic/ anaerobic-aerobic） process wasproposed on basis of existing processes which used denitrifying phosphorus removingbacteria （DPB）; its main body can be partitioned into six square compartments, whichcan be operated in different modes. The process is simple, with small lay-out area andeconomic competitive investment. DPB is enriched in the process as much as possibleto guarantee phosphorus and nitrogen removal with high efficiency and low powerconsumption. There are two main configurations and three operating modes of theprocess, and are designed with the principle of enriching DPB with longer anaerobichydraulic retention time and higher proportion of anoxic ratio in the system.Major optimization results of the parallel AN/AO process were as follows:1) Optimized parameters for configurationⅠare: Influent flow ratio （AN/AO） is12:8; SRT are 15 days; total nominal HRT lasts for six hours; internal retum ratio is200%; external return is 25%. In optimal operating conditions, averageconcentration of effluent COD, NH₃-N, TN, and TP are 49.1 mgL^-1,0.4 mgL^-1,14.8mgL^-1,and 0.8 mgL^-1 with removal efficiency of 74%, 99%, 68%, and 83%,respectively.2) Main optimized parameters for configurationⅡare: external return rate is100%; internal return rate （from the anaerobic zone to the anoxic zone） is 100%; andthe intemal anoxic-anaerobic return point is locating in anoxic reactor 1 or in anoxicreactor 3. In optimal operating conditions （SRT and HRT assumpted to be 15d and 6hrespectively）, average concentration of effluent COD, NH₃-N, TN, and TP are 45.9mgL^-1, 0.2 mgL^-1, 12.7 mgL^-1, and 0.9 mgL^-1 with removal efficiency of 74%, 99%, 74%, and 80% respectively.On basis of operation data with real wastewater, synthetic wastewater was usedto quantitatively study DPB ratio and anoxic phosphorus removal rate in the parallelAN/AO process, internal reasons for "deactivation" and "resurrection" of PAOs,types of carbon source, initial phosphorus concentration on aerobic/anoxicphosphorus removal etc. The results showed that:1) Activity of DPB in the parallel AN/AO process was about 80% that of aerobicPAOs.2) Residual nitrate concentration in the anaerobic tank and residual dissolvedorganic carbon （DOC） concentration in the anoxic tank were directly related to"deactivation" and "resurrection" phenomenon of PAO. Residual nitrate-Nconcentration in the anaerobic tank as low as 2.3 mgL^-1 and DOC concentrations inthe anoxic tank as low as 3.0 mgL^-1 can achieve desired results.3) Glucose and acetate or their mixtures can be good carbon sources for aerobic/anoxic phosphorus removal: in same conditions, anaerobic phosphorus removal ofsodium acetate, mixture of sodium acetate and glucose （with COD contribution ratio1:1）, and glucose were about 0.08gP （COD）^-1, 0.07gP （COD）^-1 and 0.04gP （COD）^-1respectively.4) Anoxic phosphorus removal efficiency was very low when the carbon sourcewas lactic acid or mixture of propionic acid and glucose, and there was no anaerobicphosphorus release at all; when the carbon source was propionic acid, anaerobicphosphorus release was normal but phosphorus removal was as low as 68% withintwo hours.5) When the carbon source was mixture of sodium acetate and propionate acid,mixture of sodium acetate and mixture of lactic acid and glucose, COD synthesisefficiencies were 77%, 78% and 76% respectively; anaerobic COD synthesis was lesscomplete when the carbon source was lactic acid, mixture of glucose and propionicacid, and propionic acid with COD synthesis efficiencies of 33%, 36% and 51%respectively.6) With same TP influent concentrations, the ranking in order of phosphorusremoval efficiencies should be 6h＞2h＞4h in terms of anaerobic retention time;while with the same anaerobic retention time, the ranking in order of phosphorus removal efficiencies should be 12 mgL^-1＞6 mgL^-1 in terms of initial influent TPconcentration.Finally, cloning and sequencing of polymer ase chain reaction-denaturinggradient gel electrophoresis （PCR-DGGE） products, FAMEs （Fatty Acid MethylEster） and quinone fingerprint technologies were used complementarily to analyzestructure of microbial community in the parallel AN/AO process; results showedthat:1) Overall microbial community structures were quite similar; however, somebacteria were different in quantity among different reactors of the process. Meanwhile,all the functional zones i.e. the anaerobic zone, the anoxic zone and the aerobic zone,had a small amount of specific microbial population.2) Dominant organisms in the parallel AN/AO process were actinomycosis suchas Rhodococcus sp.,α-proteobacterium such as Bdellovibrio sp., andβ-proteobacterium such as Thiothrix sp. When oxygen was used as electron acceptor,dominant PAOs were Dechloromonas sp., etc.; when nitrate was used as electronacceptor, dominant PAOs were Bdellovibrio sp., etc. It assumed that that microbialpopulation appeared only in the anaerobic-anoxic phosphorus removal operationmode, such as Bdellovibrio sp. were DPBs.3) When pH was changing in the range of 6.5-8.5, the microbial communitystructure of PAOs did not change much.4) There were similarities and dissimilarities features in structure of microbialcommunities among reactors of the parallel AN/AO process when analyzing withFAMEs, quinone fingerprints and SEM technologies, which can complement thePCR-DGGE results.更多还原