城市生活污水短程硝化的两个关键控制因素研究

为探寻城市生活污水实现短程硝化稳定运行的控制条件,采用序批式反应器(SBR),对影响城市生活污水短程硝化的两个关键影响因素进行了深入探讨。研究结果显示:高温有利于低C/N城市生活污水短程硝化的快速启动和稳定运行,通过分析不同温度下的NO-2-N积累速度,发现将反应器水温控制于30℃是最适宜的温度;对不同pH条件下的运行情况进行了对比分析,若要实现亚硝酸盐的高效积累,pH必须高于7.5。此外,通过对pH的调节方式进行详细探讨,推荐了一种经济高效的投药方式。     

垃圾渗滤液厌氧氨氧化脱氮技术的工程化应用探索

在两级AO工艺处理实际垃圾渗滤液工程应用程中,首先采用精准曝气控制溶解氧(Dissolve oxygen, DO)完成硝化池短程硝化反硝化启动,同时结合生物填料投加的控制策略,在60日内快速实现厌氧氨氧化功能菌群的高效自富集,其相对丰度高达4.04%。研究结果表明,当一级硝化池DO浓度由2.6 mg/L逐步降低至1.2 mg/L后,亚硝态氮积累达到70%以上。当生化池混合液中存在NH₃-N和NO^-₂-N时,在COD<1 650 mg/L且DO≈0.3 mg/L的控制条件下最有利于厌氧氨氧化菌生长增殖和发挥代谢作用。与传统运行方式相比,本研究构建的短程硝化反硝化脱氮技术可节约26.9%曝气能耗,单位水量运行电费可降低4.03元/m²。结合短程硝化反硝化启动控制策略和厌氧氨氧化菌生长的关键控制指标,提出了厌氧氨氧化脱氮技术工程应用的设计思路。     

DO对短程同步硝化反硝化除磷工艺的影响

针对碳源偏低的城市污水,采用序批式活性污泥法研究DO对短程同步硝化反硝化除磷工艺的影响,同时对短程同步硝化反硝化和反硝化除磷的机理进行探讨.试验表明:控制DO浓度可在同一个反应器内既实现短程同步硝化反硝化反应又达到反硝化除磷的效果.综合考虑COD、NH4+-N、TN、TP的出水浓度达到一级A排放标准,得出最佳的DO控制...     

污水深度处理中稳定亚硝化单元工艺的试验研究

常温下(17～24℃),以二级处理出水为原水,普通硝化污泥为种泥,通过控制曝气量创造较高的O2基质缺乏竞争梯度,成功启动短程硝化反应器,亚硝酸盐积累率高于90%.分别对0.03～0.60 mg/L等9个DO水平下的氮素化合物转化规律及DO、pH和ORP等参数的变化规律进行了研究.结果表明,通过O2基质缺乏竞争途径实现污水深度处理中的稳定亚硝化单元工艺是可行的;DO曲线特征点是最理想的过程控制参数;DO为0.30 mg/L是实现稳定亚硝化最理想浓度;DO、pH和ORP曲线特征点表征的是维持稳定亚硝化过程的转折点,而并非硝化终点.     

短程硝化反硝化生物脱氮技术的影响因素及工程应用

应用短程硝化反硝化反应处理氮肥企业排放的低碳氮比污水在经济上和技术上具有很大的应用价值。然而,诸多影响因素对这一反应的最终效果影响很大。通过查阅文献资料,总结了影响微生物短程硝化反硝化生命活动的主要因素;同时结合近期有关这一理论的工程应用情况,整理了不同短程硝化反硝化反应的工程实践结果,分析得到:亚硝化细菌在20℃时比生长速率最大,且随温度的升高而降低;反应的理想pH值应大于8.5;低DO条件下亚硝酸盐更容易得到积累。通过在工程上间接调整影响因素,可以有效控制微生物的反应类型,减少曝气量,节约运行成本。因此,讨论短程硝化反硝化反应的影响因素有利于深入开发具有较强适应性的污水处理工艺;同时,总结不同关于短程硝化反硝化反应的工程实践结果有利于更多工程应用的开发,解决更多高难废水的处理问题。     

曝气推动频繁交替A/O工艺脱氮研究

试验采用先培养再破碎硝化菌胶团的方法进行挂膜,实现了反应器运行的快速启动.之后对反应器内温度、碳氮比、溶解氧浓度、水力停留时间进行了组合试验,结果表明:温度为32℃,C/N为8,DO浓度为1.5 mg/L,HRT值为4 h 是该工艺较优水平组合;此时,TN去除率能够达到87.2%,达到了同步硝化反硝化脱氮反应的较好条件...     

好氧颗粒污泥反应器快速启动及除碳脱氮试验

为快速启动好氧颗粒污泥反应器,在SBR反应器中同时接种硝化污泥和厌氧颗粒污泥,控制反应条件,温度23~25℃,pH值7.5~8.5,DO质量浓度1.5 mg/L左右,15 d即完成反应器快速启动。形成的好氧颗粒污泥粒径1.5~2.5 mm,SVI值54 mL/g。颗粒污泥结构紧密,沉降性能良好。反应器连续运行40多天,改变进水COD及NH4+-N浓度,COD和NH4+-N去除率均能稳定在80%以上,反应器内发生了同步硝化反硝化过程。     

MBBR工艺短程硝化影响因素研究

采用移动床生物膜反应器(MBBR)处理南方城市模拟生活污水,研究了DO、pH、进水氨氮负荷及HRT等因素对出水氨氮、亚硝酸盐氮和硝酸盐氮的影响,探索了该反应器实现短程硝化的控制条件。试验结果发现,当反应器在DO=0.5~1.0mg/L、pH=8~9、进水氨氮负荷为35mg/L及HRT=14h时,获得了稳定的亚硝酸盐氮积累,实现了短程硝化。     

连续流活性污泥法实现城镇污水短程脱氮的影响因素分析

城镇污水短程脱氮工艺关键技术之一是如何将氨氧化控制在亚硝化阶段。综合分析温度、pH、DO浓度、进水C/N比、进水方式、缺氧/好氧区体积比、污泥丝状菌膨胀、SRT、HRT、氨氮负荷、污泥浓度、内回流比、化学抑制剂等因素对污水短程硝化过程的影响作用,为常温连续流条件下实现城镇污水的短程脱氮提供技术参考。     

AOMBR处理高氨氮废水的效能稳定性及影响因素研究

对AOMBR(缺氧-好氧膜生物反应器)处理高氨氮废水的脱氮效能进行了研究,着重考察了硝化效能的稳定性及影响系统稳定运行的因素.研究结果表明:在适宜的pH、DO和温度下,容积负荷＜1.5 kgNH3-N/(m3·d)时,硝化率可保持在99%以上;好氧池中DO＞1.5 mg/L能满足硝化需要;好氧池pH维持在6.8～7.2时可稳定高效地去除氨氮;碱度、污泥龄等也会对硝化效率产生影响.在好氧池中硝化率较高的情况下,影响反硝化效果主要是回流比和碳源.     

短程硝化反硝化技术研究进展

综述了国内外短程硝化反硝化的技术进展。从短程硝化反硝化技术的影响因素、控制方式以及氨氧化菌的分子生物学研究等方面进行了分析,为在更普遍、更广泛的条件下实现短程硝化生物脱氮技术提供参考和支持。     

Achieving and maintaining of short-cut nitrification in a cyclic activated sludge system

A lab-scale Cyclic Activated Sludge Technology (CAST) system was operated more than 5 months to evaluate the effects of the operation mode on nitrogen removal performance and investigate a feasible method for achieving short-cut nitrification in the system. Results showed that nitrogen was removed by conventional biological nitrification and denitrification in traditional operation mode (fill/aeration 2 h, settle 1 h, decant 1 h), whereas short-cut nitrification and denitrification was the main nitrogen removal pathway in modified operation mode and the nitrogen removal performance was enhanced. Short-cut nitrification was successfully achieved in CAST system at 17 ± 1 °C by adjusting operation conditions and the average total nitrogen removal efficiency increased by 11.4% compared to traditional mode. It was assumed that low dissolved oxygen (<1.0 mg/L) limitation combined with free ammonia (0.28-0.34 mg/L) inhibition on nitrite-oxidizing bacteria caused nitrite accumulation in modified mode. During maintaining period of short-cut nitrification, preset aeration time enhanced ammonium-oxidizing bacteria dominance. It was also found that low DO could result in overgrowth of filamentous microorganisms and poor sludge settleability. The pH variation could provide effective information for controlling aeration duration in modified mode. However, no evident breakpoint appeared on pH and DO profiles in traditional mode.     

Analysis of nitrifying bacterial communities in aerobic biofilm reactors with different DO conditions using molecular techniques

In order to assess the relationship between the dissolved oxygen (DO) concentration and the characteristics of nitrifying bacterial communities in an aerobic biofilm reactor, molecular techniques including denaturing gradient gel electrophoresis (DGGE)/cloning based on PCR targeting 16S rRNA and the amoA gene and fluorescence in situ hybridisation (FISH) were conducted. The D-1, D-2, D-3 and D-4 reactors with different DO concentrations (1, 3, 5 and 7 mg/L, respectively) were set up in the thermostat and acclimated. The optimal DO concentration with stable nitrification efficiency was above 5.0 mg/L. As was shown by the results of DGGE and cloning, the community of ammonia-oxidising bacteria (AOB) and the ratio of Nitrosomonas sp. changed only slightly despite their differing nitrification efficiencies. The results of FISH indicated that higher DO concentrations resulted in an increase in AOB and nitrite-oxidising bacteria (NOB), and a reduction in heterotrophic microorganisms. The INT-dehydrogenase activity (DHA) test demonstrated that the activity of AOB decreased with reductions in the DO concentration. This means that the DO concentration does not influence the community of AOB, but rather the activity of AOB. In the relationship between the attached biomass and the nitrification efficiency, only the active biomass affected the nitrification efficiencies.     

Operation of a nitrite-type airlift reactor at low DO concentration.

Laboratory scale experiments were performed to evaluate the feasibility and potential of nitrite-type nitrification process with an airlift reactor having aerobic granular biomass. Oxygen limitation was selected as the main control parameter for inhibiting the growth of nitrite oxidizer and thus achieving only nitritation. To enhance granule formation, seeding of methanogenic anaerobic granules was used to serve as an initial carrier material. After 90 days of operation at low DO concentration of less than 1.0 mg/l, the maximum nitrite conversion rate of 2.6 g NO2-N/L/d could be achieved. During the continuing year-long stable operation, the granular mass of nitritation granules increased to about 15 g VSS/L with an average granule size of 0.7 mm. Nitrate-N concentration was observed to be below 10 mg/L during the whole operational period. From the results of the experiments, it is concluded that a granule-type airlift reactor with DO control is feasible for achieving stable nitritation.     

Simultaneous nitrification and de-nitrification in MBR.

Experiments have been carried out to get an understanding of the effect of DO, C/N ratio and pH on the performance of a bench scale membrane bioreactor (MBR) in simultaneous nitrification and denitrification. It was found that under the conditions of MLSS in the range of 8000-9000 mg/L and temperature of water in the MBR of 24 degrees C, influent COD and NH3-N in the range of 523-700 mg/L and 17.24-24 mg/L respectively, the removals of COD, NH3-N and TN were 98%, 99% and 60%; 96.5%, 0,98% and 75%; 96%, 95% and 92%; 90%,70% and 60% respectively at DO of 6, 3, 1 and 0.5 mg/L. It was also found that the changes in C/N ratio and pH in a certain range have a slight effect on COD removal but have significant influence on the removal of NH3-N and TN. The results showed that only under the conditions that each ecological factor was maintained relatively steadily, simultaneous nitrification and de-nitrification proceeded smoothly. It was found that when C/N ratio was 30, the influent pH 7.2, the temperature of water in MBR 24 degrees C and DO 1 mg/L, as optimum conditions, the removals of COD, NH3-N and TN were 96%, 95% and 92% respectively. In addition, mechanism research on simultaneous nitrification and de-nitrification in MBR has been conducted as well.     

影响燃气轮机运行和启动的几个因素

针对S109FA燃气一蒸汽联合循环发电机组的检修和运行特点,结合该类机组的运行经验,分析了影响机组运行和启动的几个因素,供其他电厂燃气轮机运行和检修管理时参考。     

Temperature effects on biological nutrient removal system with weak municipal wastewater

The wastewater characteristics of low organic strength coupled with low temperature would be considerable variables for design and operation of biological nutrient removal (BNR) systems. But temperature studies have mostly been focused on individual process with biological phosphorus removal, nitrification and denitrification, respectively. Overall temperature effects on BNR system may not be fully represented by sum of results of separated studies on biological nutrient removal steps. The operating result of a retrofitted full scale unit along with laboratory-scale BNR unit indicated 90% of nitrification was possible at temperature as low as 8°C. However, the denitrification was turned out to be a key step to regulate the overall nutrient removal efficiencies. When the operating temperature dropped down, a rapid decrease of phosphorus removal efficiencies was observed by the nitrate in return sludge. If nitrification was not well developed, phosphorus removal returned to the normal efficiency even at low temperature of 5°C. The phosphorus removal mechanism was not influenced at this low temperature.     

DO对短程同步硝化反硝化除磷工艺的影响

针对碳源偏低的城市污水,采用序批式活性污泥法研究D0对短程同步硝化反硝化除磷工艺的影响,同时对短程同步硝化反硝化和反硝化除磷的机理进行探讨。试验表明：控制DO浓度可在同一个反应器内既实现短程同步硝化反硝化反应又达到反硝化除磷的效果。综合考虑COD、NHg—N、TN、TP的出水浓度达到一级A排放标准,得出最佳的D0控制范围。当D0浓度在0．5～1．0mg／LU时．COD的去除率达到93％～94％,Nil,＋一N的去除率为97％～98％,TN的去除率达到85％一96％,TP的去除率为91％～93％。     

Treatment of municipal wastewater in a hybrid process using a new suspended carrier with large surface area.

An activated sludge/biofilm hybrid process treating municipal wastewater was studied in pilot plant trials. A new type of suspended carrier, with large effective surface area, was employed in the process with the aim of enhancing nitrification. The pilot plant was operated for 1.5 years in five different configurations including pre-denitrification in all five and enhanced biological phosphorus removal in the final two. The wastewater temperature ranged between 11 degrees C and 20 degrees C, and the nominal dissolved oxygen (DO) level was 5-6 mg/L. The nitrification rate obtained on the new carrier within the hybrid stage was in the range of 0.9-1.2 g NH4-N/m2/d corresponding to a volumetric rate of 19-23 g NH4-N/m3/h (total nitrification including nitrification in the suspended solids). More than 80% of the total nitrification took place on the carrier (and the remainder in the suspended solids). The nitrification rate was shown to correlate with DO, decreasing when the DO was decreased. The results supported the idea of using the new carrier as a tool to upgrade plants not having nitrification today or improve nitrification in activated sludge processes not reaching necessary discharge levels. The large surface area present for nitrification makes it possible to obtain high nitrification rates within limited volumes. The possibility to keep the total suspended solid content low (< 3 g/L) and avoiding problems with the filament Microthrix parvicella, are other beneficial properties of the hybrid process.     

抽水蓄能机组的黑起动

在电网事故、自然灾害或其他原因等情况下，造成电厂全部外来厂用电源消失，且短时间内无法恢复供电，为保护电厂的安全和恢复生产，实行自救，利用仅有的直流系统启动监控专门程序使机组发电从而恢复厂用电的供电，进而恢复厂用设备的运行，称为机组黑起动。当电网因故障而停运后，通过电网内具有自动起动能力的机组起动，而恢复电网正常运行，则称为电网黑起动。十三陵蓄能电厂的设计具有机组黑起动的功能，在1998、1999和2000年进行的机组和电网黑起动试验均取得圆满的成功。黑起动问题的研究在我国还处于起步阶段，十三陵蓄能电厂进行的黑起动试验在我国是首例成功的试验，具有很好的参考价值。