温度对水解反硝化脱氮的影响

采用水解反硝化脱氮工艺,将水解酸化与反硝化脱氮过程相结合,取代缺氧反硝化,解决城镇污水冬季脱氮效果差的问题。在水解反硝化工艺的中试系统中,氨氮和总氮的去除效果受温度的影响较小,冬季和夏季氨氮去除率分别达到98.3%和98.4%,总氮去除率分别为65.2%和68.0%。以水解反硝化污泥与AAO工艺中的缺氧池污泥为研究对象,对比分析温度对两种污泥比反硝化速率和耗碳率的影响。结果显示:温度对水解池污泥的影响显著小于缺氧池污泥,在25、30℃两者反硝化速率相当,但是当温度为8、15和20℃下,水解池污泥的最大比反硝化脱氮速率分别为缺氧池污泥的1.7倍、1.3倍和1.4倍;同时,在各温度条件下,水解池污泥的耗碳率基本为缺氧池污泥的51.2%~81.7%。     

有氧情况下同时硝化/反硝化的反应动力学模式

一般的污水处理厂都是利用生物方法脱氮。通常认为，生物法脱氮是一个两阶段过程：硝化和反硝化。在硝化阶段化学自养型硝化细菌在好氧条件下将ＮＨ４＋－Ｎ转化为ＮＯ２－－Ｎ和ＮＯ３－－Ｎ；而在反硝化阶段，兼性异养细菌在缺氧条件下进行ＮＯ２－－Ｎ和ＮＯ３－－Ｎ的...     

反硝化聚磷工艺相关探讨

引言反硝化聚磷工艺是在厌氧/缺氧环境下利用以硝酸根作为电子受体的反硝化聚磷菌,通过它们厌氧释磷,缺氧存在硝酸盐情况下聚磷,并同时反硝化,达到同时利用同一细菌在同一阶段脱氮除磷的双重目的。相比传统的A2/O工艺具有节省能耗,减少运行费用,剩余污泥产量少等优点。     

短程硝化反硝化工艺简析

指出短程硝化反硝化工艺是目前国内外生物脱氮技术研究应用的热点,通过介绍短程硝化反硝化工艺原理,分析了不同工艺稳定亚硝态氮积累实现短程硝化的工艺控制措施,对短程硝化反硝化工艺今后的研究和应用进行了展望。     

短程硝化-反硝化生物脱氮

短程硝化－反硝化生物脱氮法是将硝化控制在形成亚硝酸阶段,阻止亚硝酸的进一步硝化,然后直接进行反硝化。这一方法可以克服传统生物脱氮法存在的问题,其关键是在硝化阶段维持ＨＮＯ２长久稳定地积累。本文结合国内外研究,对形成ＨＮＯ２积累的条件和影响因素进行了分析,探讨了实现短程硝化的途径。     

后置生物膜三级反硝化工艺特性及其应用

为了改善日益严峻的水环境问题,不但要提高现有污水处理系统N、P去除效率,同时应在局部敏感水域实现出水的深度脱氮除磷。三级生物膜反硝化是极具发展前景的深度脱氮工艺,在分析单级悬浮活性污泥工艺技术缺欠的基础上,综述了反硝化滤池及反硝化MBBR两种三级生物膜反硝化工艺特性,并对参与实施的生物膜反硝化脱氮工程案例进行了介绍。     

A2/O氧化沟反硝化除磷实践

反硝化除磷脱氮是利用反硝化聚磷菌,在缺氧环境下以NO3-作为电子受体来实现同步反硝化和过量吸磷作用,从而可以在低碳源情况下达到脱氮除磷目的。在此理论指导下,本文作者在A2/O微曝氧化沟工艺中进行了实践操作,得到较好的效果。     

新型短程硝化反硝化工艺处理高浓度氨氮废水

研发了一种新型短程硝化反硝化工艺——ANITATMShunt,它通过特殊的自控系统来控制N2O的释放。采用500 L的SBR中试装置处理消化污泥脱水上清液,经过18个月的稳定运行表明:通过短程硝化反硝化途径可以实现90%的脱氮率,并且释放的N2O不足总脱氮量的0.7%。将通过pH值、温度和在线监测的NO-2-N浓度实时计算的亚硝酸浓度与亚硝酸浓度设定值进行比对,以便对曝气过程进行调控,从而抑制了N2O的释放并实现了对SBR短程硝化反硝化工艺的自动控制。同时证实了在低溶解氧条件下,由氨氧化菌(AOB)在短程硝化反硝化过程中产生的N2O并非与高亚硝酸盐浓度有直接关系,而是与游离亚硝酸浓度有关。     

SBR工艺同步硝化反硝化现象及其脱氮效果

采用内径为300mm、高为650 mm的圆柱形SBR反应器进行试验,采用鼓风曝气,用温控仪控制水温在要求的范围内,由时间程序控制器控制进水、闲置、曝气、沉淀和排水全过程,用DO仪和pH计分别在线判断SBR反应器的运行状况,研究SBR系统对有机物和氮的去除过程及其脱氮效果,同时结合试验数据对有氧条件下反硝化及异养硝化菌进行较深入的分析.结果表明DO浓度控制在3～5 mg/L时,其同步硝化反硝化现象明显,脱氮效果最佳,总氮去除率可达80%,COD的去除率达90%.采用同步硝化反硝化脱氮还可以克服污水中碱度不足的现象,由于反硝化不断产生碱度,补充了微生物对有机物和含氮化合物的降解引起水中pH值的下降.当温度为18～25℃时,SBR系统氨氮的去除比较稳定,说明SBR工艺可实现常温同步硝化反硝化.     

短程硝化-反硝化生物脱氮技术研究

对传统生物脱氮工艺原理和短程硝化—反硝化工艺原理进行了比较 ,分析了短程硝化 -反硝化技术的实用价值 ,提出了实现短程反硝化的控制条件。     

Removal of organics and nutrients from food wastewater using combined thermophilic two-phase anaerobic digestion and shortcut biological nitrogen removal

A process combining pilot-scale two-phase anaerobic digestion and shortcut biological nitrogen removal (SBNR) was developed to treat organics and nutrients (nitrogen and phosphorus) from food wastewater. The thermophilic two-phase anaerobic digestion process was investigated without adjusting the pH of the wastewater for the pre-acidification process. The digested food wastewater was treated using the SBNR process without supplemental carbon sources or alkalinity. Under these circumstances, the combined system was able to remove about 99% of COD, 88% of TN, and 97% of TP. However, considerable amounts of nutrients were removed due to chemical precipitation processes between the anaerobic digestion and SBNR. The average TN removal efficiency of the SBNR process was about 74% at very low C/N (TCOD/TN) ratio of 2. The SBNR process removed about 39% of TP from the digested food wastewater. Conclusively, application of the combined system improved organic removal efficiency while producing valuable energy (biogas), removed nitrogen at a low C/N ratio, and conserved additional resources (carbon and alkalinity).     

Orbal氧化沟生物脱氮的中试研究

采用有效容积为330L的中试Orbal氧化沟模型处理城市污水,研究了Orbal氧化沟的同时硝化反硝化生物脱氮现象。结果表明,Orbal氧化沟具有良好的降解有机物和硝化性能;在不投加外碳源和不设硝化液内回流的条件下,通过控制DO浓度分布,可以实现氧化沟内的同时硝化反硝化,对总氮去除率平均为61%,出水总氮平均为14mg/L。经分析认为,DO浓度分布是氧化沟内同时硝化反硝化的决定因素,进水中的COD/TN是影响总氮去除率的重要因素;通过控制外沟低DO运行,可以稳定实现Orbal氧化沟的低能耗高效脱氮;多沟道串联的反应器布置方式有效防止了低DO运行带来的亚硝酸盐积累和污泥膨胀的发生。     

倒置A~2/O工艺的原理与特点研究

通过短时厌氧环境的生化特性、厌氧 /缺氧环境倒置效应和小型系统平行对比试验 ,较系统地研究了倒置A2 /O工艺的原理和工艺特点。指出 :①聚磷菌厌氧有效释磷水平的充分与否 ,并不是决定其在后续曝气条件下过度吸磷能力的充分必要条件。推进聚磷菌过度吸磷的本质动力与厌氧区HRT和厌氧环境的厌氧程度有关。在一定范围内 ,厌氧环境的HRT越长 ,厌氧程度越充分 ,聚磷菌的吸磷动力越强。②把常规生物脱氮除磷系统的厌氧、缺氧环境倒置过来 ,可以得到更好的脱氮除磷效果。小型系统平行对比试验表明 ,倒置A2 /O工艺的氮磷脱除功能明显优于常规A2 /O工艺 ,其COD去除能力则与常规A2 /O工艺相当。     

短好氧泥龄下A2/O和BAF联合工艺的脱氮除磷特性

采用小试装置,研究了短好氧污泥龄下A2/O和BAF联合工艺处理低C/N和C/P污水时的脱氮除磷特性.结果表明,通过提高A2/O工艺段的厌氧区有机负荷和缺氧区硝酸盐负荷对反硝化聚磷菌（DPAOs）进行选择和强化后,其在聚磷菌（PAOs）中的比例维持在28%左右,工艺具有部分反硝化除磷能力,能够减少脱氮除磷过程中对碳源的总需求量.但在联合工艺中,好氧除磷仍是主要的除磷方式.在A2/O工艺段内,好氧污泥龄在满足好氧PAOs存活的同时,还必须满足抑制硝化细菌生长的要求,且为了保证工艺对磷的整体去除效果,混合液在好氧区的接触时间须大于30 min.此外,以保证缺氧区出水中含有1～4 mg/L的硝态氮为原则来控制BAF出水的回流量,可达到较好的脱氮除磷效果.该联合工艺结合了活性污泥工艺和生物膜工艺的优点,运行稳定,出水水质优良,不仅适合于新建污水处理厂,也特别适合于不能脱氮除磷污水处理厂的技术改造.     

改善MSBR系统脱氮效果的试验研究

MSBR工艺是连续流与序操作 相结合的新型生物脱氮除磷技术,由于它的后置反硝化设计,碳源不足制约了系统的脱氮效果。为了改善这种状况,进行了将部分原水分流至缺氧区的试验。结果表明：引入原水后,缺氧区的反硝化速率常数提高了一倍,系统的反硝化速率和脱氮率相应提高。与此同时,分流造成了厌氧区的碳源不 足,加之厌氧区的回流增加,引入了较多的硝酸盐,使磷的释放和过量吸收受到影响,除磷效果下降。另外,针对中间沉淀区暴露出的运行和设计问题提出了一些改进措施。     

The effect of anoxia and anaerobia on ciliate community in biological nutrient removal systems using laboratory-scale sequencing batch reactors (SBRs)

Little is known about the effect of anaerobic and anoxic stages on the protozoan community in the activated sludge process and how this subsequently affects performance. Using a laboratory-scale BNR system the effect of different periods of anoxia on both the protozoan community and performance efficiency have been examined. Four SBRs were operated at two cycles per day using a range of combined anoxic/anaerobic periods (0, 60, 120 and 200 min). Effluent quality (TOC, BOD, TP, TN, NH₄-N, NO₃-N and NO₂-N), sludge settleability and ciliate community (species diversity and abundance) were analysed over a periods of up to 24 days of operation. The species richness and total abundance of ciliates were found to decrease with longer anoxic/anaerobic periods. Both, positive and negative significant correlations between the abundance of certain species and the period of anoxia was observed (e.g. Opercularia microdiscum, Epicarchesium granulatum), although other species (i.e. Acineria uncinata, Epistylis sp.) were unaffected by exposure to anoxia. In the laboratory-scale units, the 60 min anoxic/anaerobic period resulted in good process performance (TOC and BOD removal of 97-98% respectively), nitrification (80-90%), denitrification (52%) but poor levels of biological P-removal (12%); with the protozoan community moderately affected but still diverse with high abundances. Increasing the length of anoxia to up to 200 min did not enhance denitrification although P-removal rates increased to between 22 and 33%; however, ciliate species richness and total abundance both decreased and sludge settleability became poorer. The study shows that activated sludge ciliate protozoa display a range of tolerances to anoxia that result in altered ciliate communities depending on the length of combined anoxic/anaerobic periods within the treatment process. It is recommended that anoxic/anaerobic periods should be optimised to sustain the protozoan community while achieving maximum performance and nutrient removal.     

Anaerobic/oxic/anoxic granular sludge process as an effective nutrient removal process utilizing denitrifying polyphosphate-accumulating organisms

In a biological nutrient removal (BNR) process, the utilization of denitrifying polyphosphate-accumulating organisms (DNPAOs) has many advantages such as effective use of organic carbon substrates and low sludge production. As a suitable process for the utilization of DNPAOs in BNR, an anaerobic/oxic/anoxic granular sludge (AOAGS) process was proposed in this study. In spite of performing aeration for nitrifying bacteria, the AOAGS process can create anaerobic/anoxic conditions suitable for the cultivation of DNPAOs because anoxic zones exist inside the granular sludge in the oxic phase. Thus, DNPAOs can coexist with nitrifying bacteria in a single reactor. In addition, the usability of DNPAOs in the reactor can be improved by adding the anoxic phase after the oxic phase. These characteristics enable the AOAGS process to attain effective removal of both nitrogen and phosphorus. When acetate-based synthetic wastewater (COD: 600 mg/L, NH4-N: 60 mg/L, PO(4)-P: 10 mg/L) was supplied to a laboratory-scale sequencing batch reactor under the operation of anaerobic/oxic/anoxic cycles, granular sludge with a diameter of 500 microm was successfully formed within 1 month. Although the removal of both nitrogen and phosphorus was almost complete at the end of the oxic phase, a short anoxic period subsequent to the oxic phase was necessary for further removal of nitrogen and phosphorus. As a result, effluent concentrations of NH(4)-N, NO(x)-N and PO(4)-P were always lower than 1 mg/L. It was found that penetration depth of oxygen inside the granular sludge was approximately 100 microm by microsensor measurements. In addition, from the microbiological analysis by fluorescence in situ hybridization, existence depth of polyphosphate-accumulating organisms was further than the maximum oxygen penetration depth. The water quality data, oxygen profiles and microbial community structure demonstrated that DNPAOs inside the granular sludge may be responsible for denitrification in the oxic phase, which enables effective nutrient removal in the AOAGS process.     

交替式缺氧/厌氧膜生物反应器的脱氮除磷效能

开发出一种交替式缺氧／厌氧膜生物反应器（AAAM）的脱氮除磷工艺。该工艺由一个交替的缺氧／厌氧反应区扣一个连续曝气的好氧区组成，通过改变好氧区回流混合液的流向使缺氧和厌氧环境在两个单独的反应器（A和B）内交替形成，以实现同步缺氧反硝化、厌氧释磷及反硝化聚磷菌的部分吸磷过程。中空纤维微滤膜置于好氧区，该区采用连续曝气方式实现硝化、过量吸磷及对膜污染的控制。试验结果表明：AAAM工艺能够高效去除营养物，对COD、总氮、总磷的平均去除率分别为93％、67．4％和94．1％。     

组合式折流板反应器启动程序的研究

介绍一种组合式折流板反应器(CBR),由缺氧区—厌氧区—好氧区组成。好氧区部分出水回流至缺氧区进行脱氮,实现了A2/O与折流板反应器的嵌套,在保留厌氧折流板反应器(ABR)优点的同时,强化了COD去除率和脱氮效果。采用模拟污水,通过先启动厌氧区,再启动好氧区,最后启动缺氧区的方式成功启动了CBR,获得了启动过程中COD去除率、pH、产气量、TN等参数随时间的变化规律。反应器启动后COD去除率可以稳定达到90%以上,总氮去除率可以达到80%以上。电镜扫描结果表明,厌氧区各格室颗粒污泥具有明显的相分离特性。     

新型高效脱氮合建式氧化沟(C-Orbal)工艺的应用

新型高效脱氮合建式氧化沟(C-Orbal)是以Orbal氧化沟和周进、周出辐流式二沉池为基础,将厌氧池、缺氧池、好氧池、二沉池、内外回流与Orbal氧化沟组合在一起,具有占地面积小、投资省、水头损失小、能耗低、适应能力强、运行管理方便等优点.结合工程实例,介绍了该工艺的主要技术特点、处理效果及经济技术指标.