【作者】 马斌；

【导师】 彭永臻；

【作者基本信息】 哈尔滨工业大学 ， 市政工程， 2012， 博士

【摘要】 水体富营养化日益严重，使城市水环境恶化，甚至造成饮用水水源供应中断，严重影响了工业生产与居民的日常生活，造成了巨大的直接和间接经济损失。污水中氮磷排放是引起水体富营养化的重要原因，因此为了控制水体富营养化而兴建了大量的污水处理厂。现有污水处理厂属于能耗大户，在能源危机不断凸显的背景下，如何在实现高效脱氮的同时降低水处理能耗，降低处理费用，对于污水处理的可持续发展有着重要意义。现有污水脱氮技术需要利用有机物作为反硝化碳源才能达到污水总氮去除的目的，因此污水中的大部分有机物不能用于产甲烷。厌氧氨氧化菌的发现为污水自养脱氮提供了可能，因为厌氧氨氧化菌可以利用亚硝酸盐氧化氨氮生成氮气，而无需有机物作为碳源。现有厌氧氨氧化技术主要集中在高温高氨氮废水处理中，而城市污水厌氧氨氧化脱氮技术的研究报道甚少。为了推动厌氧氨氧化技术在城市污水处理中的应用，本文首先提出城市污水短程硝化厌氧氨氧化脱氮（自养脱氮）工艺，随后以连续流反应器作为研究对象处理实际城市污水考察了两段式城市污水自养脱氮的技术可行性。确认其技术可行性之后，提出并考察了生物强化方法快速启动与稳定维持城市污水短程硝化；在UASB反应器中成功培养出了厌氧氨氧化颗粒污泥，并考察了温度降低过程中城市污水厌氧氨氧化脱氮性能、菌群结构变化及N2O释放情况。本文对污水有机物去除、短程硝化及厌氧氨氧化技术现状进行了总结分析，提出了城市污水自养脱氮新工艺。该工艺首先将污水中的有机物富集到污泥中，污泥再去产甲烷实现能量的回收利用；随后通过短程硝化厌氧氨氧化技术将污水中的氮去除，此技术有望实现城市污水厂能量自给或能量外供。随后以去除有机物后城市污水为研究对象，采用短程硝化厌氧氨氧化工艺，考察城市污水自养脱氮技术可行性。试验结果表明在进水TN和溶解性COD浓度分别为45.87mg/L和44.40mg/L的条件下，自养脱氮工艺的TN去除率可达88.38%，证明了两段式城市污水自养脱氮具有技术可行性。提出了生物强化策略快速启动与稳定维持城市污水短程硝化，即在城市污水厂旁侧高氨氮废水处理系统实现短程硝化，将其排放的短程硝化剩余污泥投至城市污水硝化系统，从而达到快速启动与稳定维持城市污水短程硝化。试验结果表明：高氨氮废水A/O硝化系统可通过FA与FNA联合抑制实现稳定的短程硝化，亚硝酸盐积累率在95%以上；通过微孔曝气改善气液传质效果，氨氧化速率可达2.71kgN/m3/d。通过生物强化策略，即定期向城市污水硝化系统投加短程硝化污泥，同时控制反应器内溶解氧不要过高，可重复实现稳定短程硝化。在城市污水短程硝化破坏后，15天即可重建短程硝化，亚硝酸盐积累率由1%增至89%。在城市污水厌氧氨氧化UASB反应器中，通过逐渐提高进水流量来提高上升流速，成功培养出了厌氧氨氧化颗粒污泥。颗粒污泥粒径主要分布在0.5-0.9mm范围内，且颗粒污泥空隙较多，有利于传质。颗粒污泥的形成实现了厌氧氨氧化菌的富集，其丰度为1.68±0.08×109copies/ml混合液，厌氧氨氧化菌主要为Candidatus “Kuenenia stuttgartiensis”。进水量逐渐提高的过程中，HRT由1.24h降至0.12h，容积氮去除速率由0.57kg N/m3/d增至5.72kg N/m3/d；NH4+-N去除率为76.47-100.00%，平均值为92.81%； NO2--N的去除率为78.75-99.65%，平均值为94.35%，表明厌氧氨氧化菌的富集使得污水的中氮得以高效去除。在此厌氧氨氧化反应器中，N2O释放量极少，其释放速率平均为0.30×10-4kg N/m3/d，低于容积氮去除速率的0.0016%；进水中的N2O-N浓度为0.08-0.13mg/L，出水中N2O-N浓度却低于0.02mg/L，可以看出在厌氧氨氧化过程中可去除水中溶解态的N2O。通过逐渐降低厌氧氨氧化UASB反应器运行温度，研究了降温过程中城市污水厌氧氨氧化脱氮特性及菌群结构变化。温度由30℃变为16℃时，厌氧氨氧化污泥仍保持颗粒状，使得厌氧氨氧化菌在UASB内得以有效持留，颗粒污泥中厌氧氨氧化菌丰度为1.93±0.41×109copies/ml混合液。降温过程中UASB反应器容积氮去除速率逐渐降低，但16℃时容积氮去除速率仍可达2.28kgN/m3/d,NO2--N和NH4+-N去除率分别为92.31%和78.45%。降温过程中颗粒污泥中厌氧氨氧化菌由Candidatus “Kuenenia stuttgartiensis”变为Candidatus “Brocadiaanammoxidans”和Candidatus “Kuenenia stuttgartiensis”的混合菌。更多还原

【Abstract】 Eutrophication is increasingly serious, making urban water environment systemdeterioration, and even making a break of drinking water supply. This phenomenonseriously affected industrial production and people’s daily life, and caused heavydirect and indirect economic losses. The main cause of eutrophication is nutrientover enrichment, so lots of wastewater treatment plants (WWTP) were built tocontrol eutrophication. Currently, the energy consumption of WWTP is too high, sohow to reduce energy consumption and operation cost is very important for thecontinuous development of wastewater treatment.Currently, organic matter is needed as carbon source of denitrification fornitrogen removal from wastewater, so lots of organic matter can’t be used toproduce methane. The discovery of anaerobic ammonium oxidation (anammox)bacteria makes it possible to achieve autotrophic nitrogen removal. Becauseanammox bacteria can directly convert nitrite and ammonium to nitrogen gaswithout organic carbon source. Now most studies about anammox were focused onammonium rich wastewater treatment under high temperature, the studies aboutsewage treatment via anammox were very limited.In order to apply anammox in sewage treatment, a novel nitritation anammox(autotrophic nitrogen removal) process was proposed in this study. Then thetechnical feasibility of two stage autotrophic nitrogen removal from real sewage wasinvestigated in continuous reactors. Bio-augmentation strategy was proposed toachieve stable nitritation in sewage treatment. Anammox granular sludge wasformed in an upflow anaerobic sludge blanket reactor treating low strengthwastewater. Meanwhile, nitrogen removal performance, microbial communitystructure and nitrous oxide (N2O) emission were also investigated.Based on the analysis of organic matter removal, nitritation and anammoxtechnology status, a novel autotrophic nitrogen removal process treating sewage wasproposed. In this process, organic matter was firstly concentrated into activatedsludge which was used to produce methane. After then, nitrogen removal fromsewage was achieved in the nitritation/anammox process. This process makes itpossible to make wastewater treatment energy-neural or even energy-generating.The technical feasibility of two-stage autotrophic nitrogen removal from sewagewas investigated, and the result indicated that total nitrogen (TN) removal efficiencywas up to88.38%when the influent TN concentration and chemical oxygen demand(COD) concentration were45.87mg/L and44.40mg/L, respectively. This resultindicated that autotrophic nitrogen removal from sewage was feasible. Bio-augmentation strategy was proposed to achieve stable nitritation in sewagetreatment system. Firstly, nitritation was achieved in the side-line system treatingN-rich wastewater (i.e. reject water), then nitritation sludge discharged from theside-line system was added into main stream system in order to achieve a faststart-up of nitritation and maintain a stable nitritation. The results indicated thatnitritation could be achieved in N-rich wastewater treatment system with over95%of nitrite accumulation rate (NAR), and ammonium oxidation rate was up to2.71kgN/m3/d through using micro-porous aeration. In the main stream systemnitritation could be repeatedly and reliably achieved by using bio-augmentationstrategy and controlling the dissolved oxygen (DO) at relative low level. After thedeterioration of nitritation, it can be reconstructed with an increased in NAR from1%to89%within15days.Anammox granular sludge was formed in an UASB reactor treating sewagethrough gradually increasing upflow rate under moderate temperature. The majorityof granules had a diameter of0.5-0.9mm, and interstice appeared in the granulesgive an advantage for improving substrate mass transfer. The anammox bacteria wasaccumulated by forming granular sludge, and it’s aboundance was observed at1.68±0.08×109copies/ml mixed liquor. The anammox sequences in granules weremost closely affiliated to Candidatus “Kuenenia stuttgartiensis”. When the inflowrate progressively increased, HRT decreased from1.26h to0.12h, and nitrogenremoval rate (NRR) increased from0.57kg N/m3/d to5.72kg N/m3. Ammoniumremoval efficiency of the was76.47-100.00%, and the average was92.81%. Nitriteremoval efficiency of the was78.75-99.65%, and the average was94.35%. Thisindicated that nitrogen could be efficiently removed via anammox granular sludgewith a high nitrogen removal rate. The N2O emission from the anammox reactor wasvery low, and the N2O emission rate was0.30×10-4kg N/m3/d which was below0.006%of NRR. The influent N2O-N concentration was0.08-0.13mg/L, while theN2O-N in the effluent was below0.02mg/L. This indicated that N2O in influentcould be removed in the anammox reactor.Autotrophic nitrogen removal performance and microbial community structurewere studied in anammox reactor treating sewage during the decrease of temperature.When the temperature decreased from30℃to16℃, the anammox granules wasmaintained, which made a good anammox bacteria retention in the UASB reactor.The anammox bacteria aboundance was1.93±0.41×109copies/ml mixed liquor at16℃. NRR of the UASB reactor decreased with the decrease of temperature, andmaintained at2.28kg N/m3/d at16℃, while nitrite and ammonium removalefficiency were92.31%and78.45%, respectively. A shift of community from singleCandidatus ‘‘Kuenenia stuttgartiensis’’ to a combination of Candidatus ‘Brocadia fulgida’ and Candidatus ‘‘Kuenenia stuttgartiensis’’ was observed.更多还原