温度和溶解氧对短程硝化的协同影响研究

为了探究温度和溶解氧(DO)对短程硝化快速启动和稳定运行的影响,采用不同的温度和DO组合进行实验,将温度和DO对短程硝化的协同作用进行了分析,确定了短程硝化保持稳定的边界温度。在该温度下,通过分段提升DO浓度的方法,经过100个周期的运行,成功实现了短程硝化的快速启动和稳定运行,并对系统中的微生物进行了分析。结果表明:温度对短程硝化的影响更加重要,且低于边界温度后,无论如何提升DO都无法稳定短程硝化。     

晚期垃圾渗滤液短程硝化反硝化工艺特性研究

采用间歇式反应器(Batch Reactor,BR)研究了晚期垃圾渗滤液短程硝化反硝化工艺(SND)工艺特性.试验发现:在进水氨氮负荷约为0.27 gNH3—N/(L·d),温度约为27℃,pH控制在7.5时,该工艺DO浓度控制在1 mg/L时硝化效果较好.DO浓度从0.75 mg/L增加到1 mg/L时,氨氧化速率明显增加;继续再增加溶解氧浓度,氨氧化速率增加不明显.在整个过程中,亚硝酸盐积累率变化不大,维持在91％以上.当温度控制在25℃以上时,反应器处理效果较好.随着温度的下降,亚硝酸菌和反硝化菌活性降低,当温度低于25℃时,氨氧化速率和亚硝酸盐降解速率下降较快,曝气时间和出水亚硝酸盐氮浓度明显增加.     

同步短程硝化反硝化研究

分析了现有短程硝化反硝化工艺处理高浓度氨氮废水所存在的问题,试验利用序批式反应器(SBR)的内部水力特性对其进行改造,以畜禽养殖废水为研究对象,从宏观上创造同步硝化反硝化(SND)条件,并实现了同一反应器内短程硝化反硝化的同步进行,改造后系统pH值下降速度减缓,反硝化效率提高,最终出水的亚硝酸盐和硝酸盐浓度分别降低了39%和38%。     

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...     

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％。     

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。     

同步硝化反硝化的影响因素研究

为了深入研究同步硝化反硝化(SND)的影响因素,试验研究了SBR工艺中C/N、DO和pH对SND率的影响.试验结果表明,在DO=0.45 mg/L、C/N在3.33～8.32的情况下,SND率随着C/N的升高而线性升高.当C/N超过8.32时,SND率增速减缓.在C/N=8.32、DO 0.2～0.4 mg/L的情况下,SND率随DO的升高而升高,当DO超过0.4 mg/L时,SND率开始下降.在C/N=8.32、pH处于7.6～8.4的情况下,SND率随着pH的增加先升高后下降,当pH处于8时,SND率达到最高.     

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。     

短程硝化反硝化A/O膜反应器处理矿区废水的研究

利用短程硝化反硝化A/O膜反应器来处理煤矿矿区生活污水和生产废水的混合污水,主要研究短程工艺的实现和脱氮效果。最佳工艺条件为曝气池DO为1.8 mg/L时,亚硝酸盐氮得到充分积累并且总氮去除率达到91.8%。     

潜流湿地短程硝化反硝化强化脱氮研究

为探索人工湿地系统短程硝化反硝化脱氮作用对微污染水体脱氮性能的提升效果及影响因素,构建两级垂直流潜流湿地系统,对比分析了间歇进水、同步回流、预曝气等运行方式下的净水效果及含氮污染物的转化规律,结果表明:进水低碳氮比条件下,系统对COD_Cr和NH■-N的去除率稳定在60.5%～64.3%和90%以上;通过水位/水量调节方式强化湿地内部自然富氧作用,实现TN去除效果增长8%～10%,亚硝化率呈升高趋势,NO■-N的累积现象有所改善;氨氧化细菌（AOB）和氨氧化古菌（AOA）群落分布一致性和优势群菌丰度显著提升,反硝化细菌（nirS）优势种群分布同时得到改善,水位/水量调控的运行方式可以提升短程硝化效率,为反硝化反应提供更充足的底质和溶解氧条件,强化湿地系统对微污染水体的短程硝化反硝化脱氮作用。     

序批式生物膜法除磷技术研究现状

该文详述了序批式生物膜法(SBBR)的工作原理与技术特点,介绍了除磷的生化机理、工艺选择、影响因素,探讨了国内外生物膜法除磷技术的发展状况,为污水生物除磷提供了新的选择.     

The effect of temperature and sludge age on COD removal and nitrification in a moving bed sequencing batch biofilm reactor.

This study investigates the effect of temperature and the sludge age on the performance of a moving bed sequencing batch biofilm reactor (MBSBBR) for COD removal and nitrification. The experiments are conducted in a lab-scale MBSBBR operated at three different temperatures (20, 15 and 10 degrees C) with a synthetic feed simulating domestic sewage characteristics. Evaluation of the results revealed that removal of organic matter at high rates and with efficiencies over 90% was secured at all operation conditions applied. The nitrification rate was significantly influenced by changes in temperature but complete nitrification occurred at each temperature. The nitrification rates observed at 20 and 15 degrees C were very close (0.241 mg NO(x)-N/m2d, 0.252 mg NO(x)-N/m2 d, respectively), but at 10 degrees C, it decreased to 0.178 mg NO(x)-N/m2d. On the other hand, the biomass concentration and sludge age increased while the VSS/TSS ratios that can be accepted as an indicator of active biomass fraction decreased with time. It is considered that, increasing biofilm thickness and diffusion limitation affected the treatment efficiency, especially nitrification rate, negatively.     

Modeling of enhanced biological phosphorus removal in a sequencing batch biofilm reactor

A biofilm system operated for enhanced biological phosphorus removal is evaluated using a mathematical model. The influence of the influent COD concentration and the biofilm thickness are investigated. In an activated sludge system increasing the influent COD will result in a decrease of the effluent phosphorus concentration. However, in a biofilm system above a certain influent COD concentration not all COD supplied in the influent can be taken up during the anaerobic period. Other heterotrophic bacteria will then dominate the biofilm resulting in an increase of the effluent phosphorus concentration. A larger biofilm thickness will result in an increase of the total mass of polyphosphate-accumulating organisms in the system. However, it is shown that a larger biofilm thickness results in higher effluent phosphorus concentrations. The mathematical model presented is based on the IAWQ Model No. 2 modified for the biofilm system. Mass transport in the biofilm is modeled one-dimensionally. Removal of biomass through backwashing and, thus, removal of phosphorus, is included in the mathematical model. Simulations were used to explain experimental observations.     

Low temperature biological phosphorus removal and partial nitrification in a pilot sequencing batch reactor system

Partial nitrification and biological phosphorus removal appear to hold promise of a cost-effective and sustainable biological nutrient removal process. Pilot sequencing batch reactors (SBRs) were operated under anaerobic/aerobic configuration for 8 months. It was found that biological phosphorus removal can be achieved in an SBR system, along with the partial nitrification process. Sufficient volatile fatty acids supply was the key for enhanced biological phosphorus removal. This experiment demonstrated that partial nitrification can be achieved even at low temperature with high dissolved oxygen (>3 mg/L) concentration. Shorter solid retention time (SRT) for nitrite oxidizing bacteria (NOB) than for ammonia oxidizing bacteria due to the nitrite substrate limitation at the beginning of the aeration cycle was the reason that caused NOB wash-out. Controlling SRT should be the strategy for an SBR operated in cold climate to achieve partial nitrification. It was also found that the aerobic phosphorus accumulating organisms' P-uptake was more sensitive to nitrite inhibition than the process of anaerobic P-release.     

粘土分散性影响因素试验研究

在杨凌黄土中掺加不同质量百分比的钙蒙脱石、钠蒙脱石和碳酸钠,进行分散性鉴定试验、酸碱度试验,研究粘土分散性的影响因素.结果表明:杨凌黄土蒙脱石和钠离子含量都很少,呈强碱性,为非分散性土;掺人钠蒙脱石或碳酸钠的百分比越大,pH值越高,分散越明显;掺入钙蒙脱石的百分比越大,pH值越低,崩解越缓慢;钠蒙脱石、钠离子、pH值对粘土分散性有显著影响;钠离子含量较多和酸碱度为强碱性是粘土产生分散性不可缺少的两个因素,且两因素同时存在时,粘土就会产生分散.     

Effect of denitrification type on pH profiles in the sequencing batch reactor process.

Laboratory batch experiments were conducted to investigate pH profiles during partial and complete denitrification with sufficient organic carbon source. Five stirred tank-type glass vessels, with a 7 L working volume for each, were used as SBR reactors that were all operated in denitrification mode. Five levels of initial proportion of nitrogen substances, i.e. nitrate and nitrite, were used in five reactors, respectively. Results showed that, at given temperature and mixed liquor suspended solids (MLSS), partial denitrification could attain a higher pH value than complete denitrification at the end of denitrification with the same initial NOx- concentration. The larger proportion the nitrite took in initial NOx- concentration, the higher pH peak would be obtained on pH profiles during denitrification despite the same total alkalinity produced. It was found that different types of alkalinity were produced during biological denitrification with different nitrogen substances. Partial denitrification could more carbonate alkalinity produce than complete denitrification. Furthermore, some characteristic points were identified on pH profiles which could indicate the disappearance of not only nitrate, but also nitrite in system. When computers are used to detect these features, they can provide rapid, real-time information, regarding the biological state of the system.     

Effects of extracellular polymeric substances on granulation of anoxic sludge in sequencing batch reactor

Variations of extracellular polymeric substances (EPS) and its components with sludge granulation were examined in a lab-scale sequencing batch reactor (SBR) which was fed with sodium nitrate and sodium acetate. Ultrasonication plus cation exchange resin (CER) were used as the EPS extraction method. Results showed that after approximately 90 d cultivation, the sludge in the reactor was almost granulated. The content of extracellular polysaccharides increased from 10.36 mg/g-VSS (volatile suspended solids) at start-up with flocculent sludge to 23.18 mg/g-VSS at 91 d with matured granular sludge, while the content of extracellular proteins were almost unchanged. Polysaccharides were the major components of EPS in anoxic granular sludge, accounting for about 70.6-79.0%, while proteins and DNA accounted for about 16.5-18.9% and 4.6-9.9%, respectively. It is proposed that EPS play a positive role in anoxic sludge granulation and polysaccharides might be strongly involved in aggregation of flocs into granules.     

Modelling the effect of the antimicrobial tylosin on the performance of an anaerobic sequencing batch reactor.

A laboratory-scale anaerobic sequencing batch reactor (ASBR) was fed a synthetic wastewater containing glucose to study the effects of the antimicrobial tylosin on treatment performance. Measurements of methane, volatile fatty acids, and COD concentrations suggested that the addition of 1.67 mg/L and 167 mg/l of tylosin to the synthetic wastewater inhibited propionate oxidizing syntrophic bacteria and aceticlastic methanogens. The latter is presumed to be an indirect effect. A modified version of the IWA Anaerobic Digestion Model No. 1 (ADM1) with extensions for microbial storage and hydrolysis of reserve carbohydrates, and tylosin liquid-solid mass transfer and inhibition adequately described the dynamic profiles observed in the ASBR.     

Effect of sludge discharge positions on steady-state aerobic granules in sequencing batch reactor (SBR)

We have investigated the effect of sludge discharge location on the steady-state aerobic granules in sequencing batch reactors (SBRs). Two SBRs were operated concurrently with the same sludge retention time using sludge discharge ports at: (a) the reactor bottom in R1; and (b) the reactor middle-lower level in R2. Results indicate that both reactors could maintain sludge granulation and stable operation, but the two different sludge discharge methods resulted in significantly different aerobic granule characteristics. Over 30 days, the chemical oxygen demand (COD) removal of the two reactors was maintained at similar levels (above 96%), and typical bioflocs were not observed. The average aerobic granule size in R2 was twice that in R1, as settling velocity increased in proportion to size increment. Meanwhile, the production yields of polysaccharide and protein content in R2 were always higher than those in R1. However, due to mass transfer limitations and the presence of anaerobes in the aerobic granule cores, larger granules had a tendency to disintegrate in R2. Thus, we conclude that a sludge discharge port situated at the reactor bottom is beneficial for aerobic granule stability, and enhances the potential for long-term aerobic granule SBR operation.