CANON颗粒污泥高效脱氮及处理生活污水实验研究

为研究全程自养脱氮(CANON)颗粒污泥高效脱氮及处理生活污水的可行性,应用SBR反应器,首先在高氨氮条件下,通过搅拌快速启动CANON颗粒污泥,然后通过提高污泥质量浓度短时间内快速提升脱氮效能,最后研究了该工艺在生活污水中应用的可行性.结果表明:CANON颗粒污泥在40 d内成功启动,126 d颗粒粒径为760μm,负荷达1.01 kg/(m3·d),多糖与蛋白质比值变化与粒径增长相关;通过外加颗粒污泥,77 d内总氮去除负荷迅速提高到3.22 kg/(m3·d);在处理生活污水实验中实现了氮素和有机物的同步去除,可以有效应用于常温生活污水脱氮.     

SBR中不同曝气方式下CANON工艺的启动与运行

全程自养脱氮工艺(CANON)是近年来发展起来的一种新型脱氮工艺,在CANON的运行过程中,DO的控制不当很容易引起系统脱氮率下降,甚至崩溃.合理控制反应器内部溶解氧是CANON工艺稳定运行的关键.目前,关于不同曝气方式下CANON启动与运行的研究结果还存在争议,为此,本实验在序批式反应器SBR中分别采用间歇曝气SBR(R1)和连续曝气SBR(R2),研究不同曝气方式下启动CANON及其遭到延时曝气破坏后的恢复.结果表明:R1和R2分别在第21天、27天成功启动CANON.进行延时曝气破坏后,在只改变HRT与增加运行周期的条件下,R1和R2分别经过25 d、33 d成功恢复CANON.最终R1和R2的总氮去除率分别为84.32%、73.62%.在SBR中可以通过同时亚硝化/厌氧氨氧化和交替亚硝化/厌氧氨氧化两种途径提高总氮去除率,R1中两者所占比例分别为24.7%、58.54%(第86天).R1内亚硝化菌(AOB)和厌氧氨氧化菌(An AOB)具有较高的活性,硝化细菌(NOB)被抑制或淘洗得较为彻底.间歇曝气在节省运行时间的同时可以稳定实现较高的总氮去除率.     

CANON工艺研究的新进展

新型生物脱氮技术-CANON工艺为废水脱氮处理提供了一个实用而节能的新途径,介绍了CANON工艺的基本原理、研究现状以及该工艺的发展前景.     

间歇低氧曝气下CANON工艺处理生活污水的启动

利用序批式反应器（SBR）接种短程硝化和厌氧氨氧化污泥处理实际生活污水,在间歇低氧曝气条件下实现了CANON工艺的启动。同时,保证适宜的温度和污泥浓度对处理效果及系统的稳定也很重要。该运行模式下,可实现对亚硝酸盐氧化菌（NOB）的抑制淘洗,短程硝化和厌氧氨氧化为主导反应,自养脱氮体系稳定。系统稳定运行后污染物去除效果良好：进水总氮和氨氮质量浓度为63.9 mg·L^-1和62.7 mg·L^-1,出水总氮和氨氮质量浓度为12.3 mg·L^-1和7.6 mg·L^-1,总氮和氨氮去除率为77.8%和86.7%,总氮去除负荷达0.16 kg N·（m³·d）^-1。试验研究为间歇低氧曝气运行模式推广应用于城市污水自养脱氮提供了参考。     

NH4^＋-N与N02^- -N对连续流CANON反应器运行性能的影响

为提高CANON反应器的TN去除效率,采用在好氧条件下直接启动的CANON反应器进行试验.试验过程中,控制温度在35℃±1℃、pH在7.39~8.01、曝气量为31.2 m3/(m3.h)、ρ(DO)约1.5~2.0 mg/L,水力停留时间为3.7 h,分别进行了ρ(NH4+-N)与ρ(NO2--N)的试验.试验发现,在曝气量恒定的条件下,ρ(NH4+-N)过高或过低都不利于TN去除率的提高,在上述试验条件下,当ρ(NH4+-N)为310~360 mg/L时,获得超过75%的TN去除率.提高反应器中的ρ(NH4+-N)与ρ(NO2--N)有利于TN负荷的提高,但二者超过50 mg/L时,继续提高无益.在进水不包含有机碳源的条件下,CANON反应器出水的ρ(TN)依然较高,还需要进一步的处理来满足排放标准.     

常温CANON反应器内微生物群落结构及生物多样性

为研究基于亚硝化的全程自养脱氮(CANON)工艺中微生物群落结构及种属特征,从常温条件下稳定运行的CANON反应器中采集生物膜样品,并基于聚合酶链式反应-变性梯度凝胶电泳(PCR-DGGE)技术,分别对总细菌、氨氧化细菌和厌氧氨氧化菌进行群落结构解析.结果表明:反应器中与亚硝化作用有关的功能菌为亚硝化单胞菌属(Nitrosomonas)和亚硝化螺菌属(Nitrosospira),与厌氧氨氧化作用有关的功能菌是Candidatus Brocadia属和CandidatusKuenenia属,未检测到亚硝酸盐氧化细菌,且系统内氨氧化细菌的生物多样性明显高于厌氧氨氧化菌.此外,反应器中还存在其他微生物,如Shewanella 、Pseudomonas 、lgnatzschineria、Dechloromonas以及属于Clostridia、α-Proteobacteria、Bacillales的uncultured bacteium等.     

常温低氨氮污水生物滤池CANON工艺的实现

基于厌氧氨氧化反应的生物自养脱氮是目前污水处理中最为经济的脱氮途径。采用装有火山岩活性生物陶粒滤料的反应器,在常温(8～25℃)条件下对低NH4+-N(60～90mg.L-1)城市污水进行试验研究,通过改变曝气等运行工况,经过硝化自然挂膜、优选亚硝酸细菌和培养厌氧氨氧化菌3个阶段之后,实现了生物滤池同步亚硝化/厌氧氨氧化生物自养脱氮。结果表明,DO控制可作为反应器启动的主要控制因子,通过在生物滤池上方水柱中进行曝气和处理水携氧内循环联合的方式,可以实现对生物膜系统内DO浓度的良好控制。运行过程中可以通过pH值的变化来对反应周期进行判断,pH值的第二个突跃点是系统反应周期结束的标志。     

Impact of inocula and growth mode on the molecular microbial ecology of anaerobic ammonia oxidation (anammox) bioreactor communities

The composition of distinctly inoculated granular anammox and biofilm-based completely autotrophic nitrogen removal over nitrite (CANON) bioreactors was investigated from start-up through continuous long-term operation via denaturing gradient gel electrophoresis (DGGE) and sequencing. The granular anammox reactor was seeded with sludge from an operational anammox reactor in Strass, Austria. The CANON reactor was seeded with activated sludge from a local wastewater treatment plant in New York City. The principal anammox bacteria (AMX) shifted from members related to Kuenenia stuttgartiensis present in the initial inoculum to members related to Candidatus Brocadia fulgida during pre-enrichment (before this study) and to members related to Candidatus Brocadia sp. 40 (during this study) in the granular reactor. AMX related to C. Brocadia sp. 40 were also enriched from activated sludge in the CANON reactor. The estimated doubling times of AMX in the granular and CANON reactors were 5.3 and 8.9 days, respectively, which are lower than the value of 11 days, reported previously. Both the granular anammox and CANON reactors also fostered significant amounts of ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB). The fractions of AMX and two groups of NOB were generally similar in the granular anammox and CANON reactors. However, the diversity and fractions of AOB in the two reactors was markedly different. Therefore, it is suggested that the composition of the feed and extant substrate concentrations in the reactor likely select for the microbial community composition more than the inocula and reactor configuration. Further, such selection is not equivalent for all resident communities.     

Enhancing completely autotrophic nitrogen removal over nitrite by trace NO2 addition to an AUSB reactor

BACKGROUND: Completely autotrophic nitrogen removal over nitrite (CANON) could decrease energy consumption and CO₂ release compared with conventional nitration–denitrification. Trace NO₂ addition could enhance the activities of aerobic and anaerobic ammonium oxidation. RESULTS: An aerated upflow sludge bed (AUSB) reactor inoculated simultaneously with aerobic and anaerobic ammonium oxidizing sludge was operated to cultivate granular sludge capable of carrying out CANON. The results showed that the efficiency and rate of total nitrogen (TN) removal reached 61% and 0.114 kgN, respectively (m^?3 day^?1) for DO = 0.5–0.6 mg L^?1. Batch tests indicated that trace NO₂ addition could increase the CANON activity of sludge. The TN removal rate and efficiency of the reactor was increased to 0.234 kgN m^?3 day^?1 and 63%, respectively, when the reactor was aerated with air containing 2.7–3.3 mmol m^?3 NO₂ and DO was at 0.5–0.8 mg L^?1. CONCLUSIONS: Trace NO₂ addition provides an alternative to increase the capacity of a CANON system at low DO concentration. Copyright © 2009 Society of Chemical Industry     

CANON工艺脱氮处理二沉池出水的研究

采用一套有效容积为150mL的上向流生物滤池反应器,接种实验室所培养的厌氧氨氧化污泥,在反应器停止运行约1年后,以自配的含NH4+-N和N02-N废水为进水,恢复启动CANON工艺.反应器启动成功后,以二沉池出水为对象,进行脱氮处理研究.试验结果表明,通过控制进水基质溶解氧的方法,经厌氧氨氧化过程转化,成功启动了CANON工艺,共耗时38d,NH4+-N的容积负荷为168g·m-3·d-1,NH4+-N的去除率在90%左右,TN的去除率在70%左右.在二沉池出水NH4+-N质量浓度为25-35mg·L-1,COD为40-60mg·L-1,UV254为0.6-0.9cm-1,HRT为3h,DO质量浓度在0.4 mg·L-1左右的条件下,稳定运行25d,NH4+-N的去除率在95%左右,TN的去除率在65%左右,COD和UV254的平均去除率分别为17%与4%.