厌氧氨氧化结构体、形态与功能

厌氧氨氧化工艺是一种新型废水生物脱氮工艺,已成为环境工程领域的研究热点并得到广泛应用。厌氧氨氧化颗粒污泥床反应器是一种高效生物反应器,以颗粒污泥形态存在的生物相是这种反应器高效工作的必要基础。在颗粒污泥床反应器中,生物相由大到小可依次分为污泥床体、颗粒污泥以及功能菌群。综述了厌氧氨氧化结构体的形态和功能及其与装置工况的密切关系,以期为反应器的实时优化和过程控制提供指导。     

盐度对厌氧氨氧化脱氮效能的影响

以实验室培养的Candidatus Jettenia属厌氧氨氧化颗粒污泥为种泥,通过批次与连续试验,考察了盐度对Anammox脱氮效能的影响。结果表明以Candidatus Jettenia为优势菌属的Anammox污泥对盐度的增加表现敏感。在连续试验中,UAFB反应器经55 d无盐环境的启动,总氮去除速率达到1.15 kg/(m~3·d),当盐度为5、7.5 g/L时,反应器脱氮效率分别下降了20%、60%,但仍能表现出显著的厌氧氨氧化效能。批次试验中,5、7.5、10 g/L盐度下,Anammox污泥活性分别下降了25%、55%、67%;盐度15 g/L时,Anammox菌失去活性。     

氧化还原电位对膨胀颗粒污泥床反应器的指示作用

对EGSB反应器异常运行状态时COD、挥发酸、氧化还原电位(ORP)、碱度、pH值进行了测试与分析。结果表明,ORP对EGSB反应器的异常运行反应敏感,由于ORP可方便地实现在线监测,可作为实际工程中厌氧反应过程是否正常运行的指示参数。     

The maximum thickness of upper shear layers of granular materials in rotating cylinders

Published data from Henein et al. (Metallurgical Transactions 14B (1983a) 191-206), Woodle and Munro (Powder Technology 76 (1993) 241-245), Boateng and Barr (Journal of Fluid Mechanics 330 (1997) 233-249), Van Puyvelde et al. (Transactions of the Institute of Chemical Engineers 78A (2000) 643-650), and Felix et al. (Powder Technology 128 (2002) 314-319) on the maximum thickness of shear layers at the upper surface of a freely flowing granular material being rotated in a cylindrical drum are modeled and analyzed. A theory is developed which suggests that all distances should be scaled by x_m, or half the length of the shear layer, which should remove most of the explicit dependence on the filled fraction. The rolling regime is predicted to contain two extreme regimes. The dispersive (inertial) regime occurs when the parameter Fr_s(x_m/σ)^4/3 is small (large), and is characterized by the dominance of dispersive (inertial) effects. Here Fr_s is a particle-dependent Froude number scaled by x_m, and σ is the particle diameter. An author-dependent and particle-dependent parameter λ is introduced to account for the different definitions and particle types used. Regression analysis shows that most of the data sets above (for the rolling regime) are approximately described by the dispersive regime. Our theory predicts that shear layers in the rolling regime should be almost identical for fill fractions symmetric about the half-filled level. All of the data analyzed satisfy essentially the same scale-up relationship, and does not support the idea that the maximum shear layer thickness should be about ten particle diameters.     

Mixing in vibrated granular beds with the effect of electrostatic force

In this study, the DEM (Discrete Elementary Method) is used to simulate the behavior of granular mixing in vibrated beds. First, the velocity fields are simulated by the DEM model to examine the convective currents in a three-dimensional vibrated granular bed. Then, in order to characterize the effect of electrostatic force on the granular flow, the electrostatic number Es is defined as the ratio of the electrostatic force to the particle weight. Also, to quantify the quality of mixing, the mixing degree M is used by the well-known Lacey index. The top–bottom and the side–side initial loading patterns of two groups of glass bead with different colors are employed to investigate the influence of the convective currents on the granular mixing. To simplify the electrostatic effect, these two groups of glass beads are given opposite charges and the charged strength is assumed to be constant. The simulation results demonstrate that the granular temperatures increase linearly with the increasing Es number. Meanwhile, the mixing rate constants, calculated from the time evolutions of mixing degree, increase with the increasing Es number in power law relations. The role of granular temperature in the granular mixing is also discussed in this paper.     

The influence of granular flow rate on the performance of a moving bed granular filter

The goal of this study is to evaluate the effect of granular flow rate on the performance of a moving bed granular filter designed for hot gas filtration of fine char particles (dust) produced during fast pyrolysis of biomass. The filter employs a counter-current configuration, in which down-flowing granular material spreads out at the bottom of the filtration vessel to form an interfacial area where the dusty gas enters the granular bed and much of the gas cleaning is hypothesized to occur. This study uses a real-time particle counter to measure the instantaneous filtration efficiency during cold flow tests of the filter. Differential pressure measurements at various locations within the granular bed are used to assess the level of char dust hold-up over time. These experiments reveal a critical granular residence time below which the filter must be operated to achieve filtration efficiencies exceeding 99%. Operating above the critical value causes the filter to “clog” and decrease in efficiency. The clogging is characterized by a critical dust volume fraction as determined through a fixed bed filtration test. The filter is found to accumulate most of the dust at the interfacial region. Also the interfacial region is more efficient than the downcomer section of the granular bed in removing dust. Decreasing residence time of granular material in the filter reduces the hold-up of char dust in the filter, which is expected to mitigate coking reactions of organic vapors when the filter is used to remove char from fast pyrolysis gas streams.     

混合填料固定床Anammox工艺启动及运行性能研究

采用蜂窝状聚乙烯填料和环型无纺布填料组合成的混合填料填充固定床反应器,考察了其Anammox工艺启动和运行性能。启动阶段进水NH_4~+-N和NO_2~--N分别为70 mg/L,HRT为48 h,温度为35℃,经过53 d培养,反应器成功启动。启动阶段(1~53 d)NH_4~+-N、NO_2~--N和总氮最大去除率分别为90.24%、100%和88.8%。负荷提升阶段(55~87 d)最大总氮负荷率和总氮去除速率分别为0.31 kgN/(m~3·d)和0.25 kgN/(m~3·d),此时,其相应的NH_4~+-N和NO_2~--N去除率分别为89.66%和99.84%。     

Model-evaluation of the erosion behavior of activated sludge under shear conditions using a chemical-equilibrium-based model

The primary particles would erode from the sludge surface under shear conditions. As the primary particles have significant effects on the solid–liquid separation process, the erosion behaviors of activated sludge in biological wastewater treatment processes under shear conditions were investigated using a chemical-equilibrium-based model. The equilibrium dispersed mass concentration of the primary particles in the sludge solution was found to nonlinearly increase with the solid content and shear intensity, and could be well described by the model. Compared with other sludge reported in literatures, the activated sludge used in this study was found to be more stable during the shear test, with a high equilibrium constant K⁰ of 30.2 and a low Gibbs’ free energy of adhesion (ΔG⁰) of −3.41 at a shear intensity of 800 s⁻¹. The two parameters could be used to evaluate the strength of the sludge. The negative value of ΔH indicates the energy demand for the erosion process. The low value of ΔH for the activated sludge used in this study indicates that the erosion process was more energy demanding and the erosion process was less shear dependent for the activated sludge used in this study.     

The effect of vibrating conditions on the electrostatic charge in a vertical vibrating granular bed

In this study, we carried out experiments to measure the electrostatic charge of a granular matter in a vertical shaker device. The purpose was to quantify the effect of the vibrating conditions on electrostatic charging in the granular matter. In each experimental run, 3 mm glass beads were first discharged to remove any residual charge prior to subsequently studying their electrostatic charging. The accumulative electrostatic charges of the granular materials were measured using a Faraday cage. The findings show that the vibrating conditions play an important role in the saturated electrostatic charge and time constant. The electrostatic charges of granular materials are mainly generated by the contact potential difference mechanism in the vibrating granular system. The results show that the saturated accumulation charge increases as the dimensionless vibrating acceleration increases, and decreases with increasing vibrating frequency. The time constant is small when a higher vibrating frequency is applied in the vibrating granular system. Finally, we demonstrate that the saturated accumulation charge increases linearly with the increase of the dimensionless vibrating velocity regardless of the vibrating frequency.     

SBR反应器结构对好氧颗粒污泥形态的影响及其动力学分析

采用屠宰废水酸化池出水,在高径比分别为11.1和1.2的SBR反应器(编号分别为R1和R2)中培养好氧颗粒污泥(AGS),考察了AGS的形成过程及其对COD的去除效果.结果表明,R1反应器运行29d形成了圆形AGS,R2反应器运行44d形成了圆柱状AGS,并且形成过程具有反复性.当圆形AGS粒径为2mm,纵横比接近1,...     

连续流中氮负荷对好氧颗粒污泥的稳定性影响

研究了连续流反应器中好氧颗粒污泥（AGS）处理无机高氨氮废水的脱氮性能及稳定性。接种成熟AGS启动反应器,前55天内进水氮负荷由1.0 kgm-3d-1逐步提升至4.0 kgm-3d-1,56~125天内氮负荷逐步减小至1.4 kgm-3d-1,126~145天氮负荷再次升高至2.0 kgm-3d-1。前75天内观察到明显的颗粒破碎及污泥流失,且颗粒平均粒径不断减小。虽然多次补充接种AGS以维持系统稳定性,但前90天内颗粒的污泥容积指数（SVI）、胞外聚合物（EPS）及比耗氧速率（SOUR）剧烈波动。受疫情影响,91~109天反应器原位闲置。重新运行后AGS的理化指标逐渐趋于稳定。前45天内氨氮去除率逐渐增大至98%以上,在46~75天内迅速减少至50%左右,此后再次回升至99%以上。总无机氮去除率大部分时间处在35%~45%之间。通过污泥截留试验探索了反应器对污泥的选择性筛分效果。当沉淀池中挡板深度为27 cm时,反应器对污泥的截留率在98%以上,出水污泥粒径多为0~0.30 mm污泥。利用高通量测序分析污泥菌群组成变化。与接种AGS相比,145天时AGS中的硝化细菌属（Nitrosomonas）相对丰度明显增大,而反硝化细菌属（unclassified_Flavobacteriaceae、unclassified_Xanthomonadaceae、Thauera等）的相对丰度略有降低。     

有机负荷波动频次对好氧颗粒污泥的影响

为了探究在低强度进水条件下有机负荷波动频次对好氧颗粒污泥（aerobic granular sludge,AGS）的影响,设置3个序列间歇式反应器（sequence batch reactor,SBR）R1、R2和R3,以合成配水为基质,高低有机负荷率（organic load rate,OLR）分别为0.67g/(L∙d)、0.67g/(L∙d),0.74g/(L∙d)、0.56g/(L∙d),0.74g/(L∙d)、0.56g/(L∙d);定义有机波动频次为每12天完成高低OLR波动的次数,R1的OLR恒定,R2、R3分别每12天、4天完成一次OLR的高低波动,波动频次分别为0、1、3。由实验结果可知,R1、R2和R3的平均粒径分别可达到318.86μm、426.71μm、593.06μm,胞外聚合物（extracellular polymeric substance,EPS）含量（以volatile suspended solids,VSS计）可达到71.97mg/g、75.88mg/g、80.35mg/g,蛋白质/多糖（protein/polysaccharide,PN/PS）分别为4.24、5.14、5.72,表明波动频次为3时颗粒具有更高的疏水性、稳定性。此外R1、R2、R3的内碳源储存率（internal carbon storage rate,CODin）、同步硝化内源反硝化（simultaneous nitrification internal denitrification rate,SND）率分别为97.06%和44.74%、98.37%和58.20%、98.91%和64.42%、总磷（total phosphorus,TP）平均去除率分别为86.82%、89.36%、92.65%,总氮（total nitrogen,TN）平均去除率分别为71.69%、74.31%、78.55%,说明波动频次为3时颗粒具有更高的碳源利用率与污染物去除能力。     

螺旋升流式反应器系统较长泥龄时运行效果及其流态释因

结合螺旋升流式反应器（SUFR）的特性,通过对比试验分析SUFR系统在较长泥龄时（主要在32 d左右）营养物去除的工艺特点。试验结果表明,SUFR系统（θ_c=32 d）出水COD和TN分别小于40 mg·L^-1﹑10 mg·L^-1,SUFR系统（θ_c=32 d）除磷率随着泥龄的延长有一定的下降,但出水TP一直稳定在1 mg·L^-1内, SUFR系统（θ_c=32 d）的SOUR值为10～18 mg·g^-1·h^-1。流态模拟结果表明,SUFR系统中单元反应器的推流流态容积利用率为63%。这说明SUFR系统反应器以活塞流为主要特征的流态特性有助于减轻较长泥龄对污水处理的负影响。该系统具有更宽的泥龄适宜范围。     

间热径向流反应器料层厚度对煤热解特性的影响

考察了方形径向流固定床煤热解反应器中变化煤层厚度对料层升温速度及煤热解产物分布特性的影响。随着料层厚度增加,导致煤热解反应要求的时间增长,热解水和气的产率相应增加,焦油和半焦收率逐渐降低,但焦油中轻质组分(沸点低于360℃组分)含量呈升高趋势,半焦和煤气热值稍许降低。如,加热壁温度900℃、从45 mm至105 mm增加煤料层厚度时,焦油产率从7.17%(质量,下同)下降到6.26% (相对干基煤),但焦油中的轻焦油组分含量则从67%升至72.7%,半焦产率由80.0%降至77.0%,热解水和煤气产率分别由6.96%和5.91%增至8.85%和7.90%,煤气热值则由24348.5 kJ·m^-3下降至20649.2 kJ·m^-3。所得半焦的热值径向上由高温侧向低温侧逐渐降低,煤料层越厚、热值降幅越大,而相同煤料层厚度处与加热壁平行的同一轴向平面上的半焦热值基本相同。针对研究的反应器,气相热解产物在反应器内沿径向(横向)由高温料层区向低温料层区流动。在该过程中伴随着热解产物对远离加热壁的低温煤料的传热、热解生成重质组分的冷凝和在煤/半焦颗粒表面的吸附截留,进而在低温料层进一步升高温度时发生二次裂解等物理化学过程。反应器内煤层厚度越大,上述各种伴随的物化作用越显著,从而明显影响煤料层的升温及热解特性。     

污泥固体停留时间对实时控制生物脱氮SBR中亚硝酸盐积累的影响

In this study,four sequencing batch reactors(SBR),with the sludge retention time(SRT)of 5,10,20 and 40 d,were used to treat domestic wastewater,and the effect of SRT on nitrite accumulation in the biological nitrogen removal SBR was investigated.The real-time control strategy based on online parameters,such as pH,dissolved oxygen(DO)and oxidation reduction potential(ORP),was used to regulate the nitrite accumulation in SBR. The model-based simulation and experimental results showed that with the increase of SRT,longer time was needed to achieve high level of nitritation.In addition,the nitrite accumulation rate(NAR)was higher when the SRT was relatively shorter during a 112-day operation.When the SRT was 5 d,the system was unstable with the mixed liquor suspended solids(MLSS)decreased day after day.When the SRT was 40 d,the nitrification process was significantly inhibited.SRT of 10 to 20 d was more suitable in this study.The real-time control strategy combined with SRT control in SBR is an effective method for biological nitrogen removal via nitrite from wastewater.     

接种颗粒污泥UASB反应器处理味精-卡那霉素混合废水

采用屠宰废水中培养的颗粒污泥接种启动中温（３５±１）℃ ＵＡＳＢ反应器处理味精－卡那霉素混合废水,反应器能随较高浓度的硫酸盐,氨氮和的氯化物。当ＨＲＴ为２－３ｈ,容积负荷率可达３５－４０ｋｇ ＣＯＤ／（ｍ＾３．ｄ）,ＣＯＤ去除率为７５％－８０％,进水ＣＯＤ／ＳＯ＾２－４可低至４－５。     

温度降低对UMSR处理高氨氮低碳氮比养猪废水效能的影响

针对干清粪养猪废水高氨氮低碳氮比的特点,前期研发了升流式微氧活性污泥反应器（UMSR）,在23℃条件下可实现碳氮的高效同步去除。为降低处理成本,在HRT 8 h和出水回流比45：1的条件下,对UMSR在20℃、17℃和15℃下的COD、NH₄⁺-N和TN去除效果进行了考察。结果表明,当温度阶段性地从20℃降低为15℃时,UMSR对养猪废水COD的去除率变化不大,均可保持在60%以上,但NH₄⁺-N和TN去除率分别从98.9%和79.8%左右大幅下降到了61.8%和39.7%左右。在17℃条件下,UMSR对COD、NH₄⁺-N和TN的去除率分别平均为62.4%、80.7%和71.2%,出水浓度分别为71、55.5和80.7 mg·L^-1左右,完全满足《畜禽养殖业污染物排放标准》（GB 18596-2001）的要求。在15～20℃范围内,温度的降低并没有显著改变UMSR系统的脱氮机制,仍然保持着以anammox为主要脱氮途径的特征。     

The effect of lauric acid shock loads on the biological and physical performance of granular sludge in UASB reactors digesting acetate

The specific activity of acetotrophic methanogens and the physical behaviour of granular sludge in laboratory-scale upflow anaerobic sludge bed (UASB) reactors subjected to shock loads of lauric acid in the absence and presence of calcium were studied. In the absence of calcium, lauric acid completely inhibited acetotrophic methanogens above a threshold level of 100 mg C_12:0dm^?3, whereas no inhibition occurred below this threshold concentration. Addition of an equivalent amount of calcium to wastewater containing lauric acid prevented inhibition of acetotrophic methanogens at least up to 1500 mg C_12:0dm^?3. Addition of less than an equivalent amount of calcium apparently removed more than a stoichiometric amount of lauric acid: 50 % inhibition occurred at approximately 700 mg ‘free’ or excess C_12:0dm^?3. The results indicate that complete sludge wash-out from conventional UASB reactors is likely to occur within 2-8 h if the system is overloaded with an influent containing more than 100 mg C_12:0dm^?3. Calcium did not prevent wash-out.