膜生物反应器亚硝化性能的影响因素研究

利用膜生物反应器成功启动了亚硝化工艺处理人工合成废水.为了确定影响亚硝化工艺效果的因素,先后对温度和溶解氧浓度进行了研究,结果表明,在温度35℃并且NH4+-N负荷平均0.45 kg.(m3.d)-1和溶解氧0.5 mg/L的条件下,可使出水中NO3--N的浓度低于20 mg.L-1,而ρ(NO2--N)∶ρ(NH4+-N)接近1.0.同时发现反应器运行期间,在低溶解氧的情况下,膜组件的污染并不严重.荧光原位杂交分析发现,在膜生物反应器中氨氧化菌成为优势菌种,亚硝酸盐氧化菌的活性受到了抑制.微生物群落分析则进一步提供了实现亚硝化工艺所必需的生物信息.     

Production of N2O in two biologic nitrogen removal processes: a comparison between conventional and short-cut nitrogen removal processes

The N2O production in two nitrogen removal processes treating domestic wastewater was investigated in laboratory-scale aerobic-anoxic sequencing batch reactors （SBRs）. Results showed that N2O emission happened in the aerobic phase rather than in the anoxic phase. During the aerobic phase, the nitrogen conversion to N2O gas was 27.7% and 36.8% of NH＋-N loss for conventional biologic N-removal process and short-cut biologic N-removal process. The dissolved N2O was reduced to N2 in the anoxic denitrification phase. The N2O production rate increased with the increasing of nitrite concentration and ceased when NH＋-N oxidation was terminated. Higher nitrite accumulation resulted in higher NEO emission in the short-cut nitrogen removal process. Pulse-wise addition of 20 mg NO2 -N. L- 1 gave rise to 3-fold of N2O emission in the conventional N-removal process, while little change happened with 20 mg NOS-N L-1 was added to SBR1.     

辽河口芦苇湿地土壤氨氧化菌的时空变化

采用传统的最大或然数法(MPN)和不依赖于培养的变性梯度凝胶电泳技术(DGGE),对辽河口芦苇湿地土壤中AOB的丰度、多样性进行了解析,并试图探究AOB同土壤可溶性盐分等环境因素之间的关系.结果表明:芦苇湿地土壤中AOB多样性指数时空分布存在较大差异,同一月份中不同站点之间群落结构相似性较大,AOB细菌数量与土壤可溶性盐分之间存在显著负相关关系(P<0.05),与土壤总氮和有机质含量之间存在极显著性正相关关系(P<0.01),表明盐分、总氮和有机质含量是辽河口湿地AOB数量时空分布的重要影响因素.     

Impact of acetochlor on ammonia-oxidizing bacteria in microcosm soils

Acetochlor is an increasingly used herbicide on corn in North China. Currently, the effect of acetochlor on soil ammonia-oxidizing bacteria (AOB) communities is not well documented. Here, we studied the diversity and community composition of AOB in soil amended with three concentrations of acetochlor (50, 150, 250 mg/kg) and the control (0 mg acetochlor/kg soil) in a microcosm experiment by PCR-DGGE (polymerase chain reaction-denaturing gradient gel electrophoresis) and the phylogenetic analysis of excised ...     

硝化悬浮填料塔中氨氧化细菌群落稳定性特征分析

利用PCR-DGGE分析技术,对于化学生物絮凝处理工艺中悬浮填料塔的氨氧化细菌(AOB)群落进行了研究。主要考察了曝气强度和水力停留时间2个运行参数调整的情况下,系统AOB群落结构的变化。生物膜样品直接取自硝化填料塔,多维尺度(MDS)方法用于DGGE电泳图谱的分析,分析结果以二维图形向量的方式显示,结果表明,曝气强度和水力停留时间均对AOB群落有一定的影响,主要的AOB种类在运行过程中基本不变,系统对于运行条件具有良好的稳定性。     

高效氨氧化菌群富集、驯化及其动态变化规律分析

利用选择性培养基对氨氧化菌群进行了连续驯化,得到了氨氮去除效率稳定的氨氧化菌群。采用平板菌落计数法结合聚合酶链式反应-变性梯度凝胶电泳(PCR-DGGE)技术考察了氨氧化菌群在连续传代过程中数量及群落结构的动态变化,并考察了pH值、碳源(HCO3-)浓度和氨氮浓度等因素对氨氧化菌群去除氨氮效率的影响。结果表明,通过连续驯化,氨氧化菌的比例由最初的1.8%提高到了31.3%。在碳源浓度为1.5 mg/L,NH4+-N初始浓度为200 mg/L,pH值为8的条件下,菌群对氨氮的去除率达99%以上。     

晚期垃圾渗滤液的部分亚硝化

利用实验室小试SBR在(33±1)℃的条件下,通过动态调控溶氧浓度(DO)(2～7 mg/L)和水力停留时间(2～5 d),经过130 d的运行成功启动了晚期垃圾渗滤液(NH4+-N含量1 227～2 133 mg/L)的部分亚硝化,使出水NO2--N∶NH4+-N稳定维持在1∶1左右,为后续的厌氧氨氧化工艺创造了进水条件。利用实时荧光定量PCR研究启动过程中的特异微生物氨氧化细菌的含量变化表明,氨氧化细菌的含量与NO2--N的生成速率和出水NO2--N稳定性有着显著相关性。     

不同碳源条件下污水生物脱氮过程中N_2O的释放规律

以3类常用的碳源(乙酸钠、葡萄糖和甲醇)为研究对象,在3个稳定运行的SBR系统内考察了碳源种类对污水生物脱氮过程中N_2O释放的影响。结果显示,各系统内N_2O的释放主要发生在好氧硝化阶段,且在以乙酸钠为碳源的系统内氨氧化速率最快,TN去除率最大,但同时N_2O的释放速率、累积释放量(4.44 mg)和转化率(1.3%)也最大。而以甲醇为碳源的小试系统脱氮效果较差,TN去除率仅为59.5%,但N_2O的释放速率、累积释放量和转化率均最低。在实际污水处理过程中,当以温室气体N_2O释放作为判断标准时,此研究结果可为碳源的选择提供依据。     

Achieving nitritation at low temperatures using free ammonia inhibition on Nitrobacter and real-time control in an SBR treating landfill leachate

Free ammonia(FA) inhibition on nitrite-oxidized bacteria(NOB) and real-time control are used to achieve nitrogen removal from landfill leachate via nitrite pathway at low temperatures in sequencing batch reactor. The inhibition of FA on NOB activity during the aerobic period was prolonged using real-time control. The degree of nitrite accumulation was monitored along with variations of the ammonia-oxidizing bacteria and NOB population using fluorescence in situ hybridization techniques. It is demonstrated that the end-point of ammonia oxidization is detected from the on-line measured dissolved oxygen,oxidization–reduction potential, and p H signals, which could avoid the loss the FA inhibition on NOB caused by excess aeration. At low temperature(13.0–17.6°C), the level of nitrite pathway rapidly increased from 19.8% to 90%, suggesting that nitritation was successfully started up at low temperature by applying syntrophic association of the FA inhibition and real-time control, and then this high level of nitrite pathway was stably maintained for as long as 233 days. Mechanism analysis shows that the establishment of nitritation was primarily the result of predominant ammonia-oxidizing bacteria developed in the nitrifying bacteria population compared to NOB. This was mainly due to a gradual reduction of nitrite amount that is available to provide energy for the growth of NOB,eventually leading to the elimination of NOB from the bacterial clusters in sequencing batch reactor sludge system.     

基于间歇饥饿的SNAD工艺运行

在室温下(22℃±3℃)用SBR反应器运行SNAD工艺,通过定期延长系统水力停留时间,营造间歇饥饿环境,探讨间歇饥饿策略下SNAD工艺的运行情况.结果表明,系统经过间歇饥饿运行后,好氧阶段末的NO_3~--N浓度降至8. 72 mg·L~(-1),亚硝酸盐积累率达到83. 18%,表明NOB活性得到了有效抑制,实现了亚硝化性能的提高;系统经过间歇饥饿运行后,好氧阶段末的亚氮与氨氮基质的比例得到调整,为后续厌氧氨氧化过程提供了合适底物,使出水氨氮浓度降至1. 0 mg·L~(-1)以下,同时由于出水硝氮浓度降低,总氮去除率达到了92. 07%左右,系统处理性能提高;通过测定功能菌活性,发现饥饿后亚硝化性能提高的主要原因是饥饿期AOB活性衰减速率低于NOB及恢复期前期AOB活性恢复速率显著高于NOB.