生物流化床在废水处理中的应用

从生物流化床的基本反应原理出发,通过食品厂废水、化工废水处理中的实际运用实例论述生物流化床在废水处理中的特点。     

内循环三相生物流化床处理废水研究进展

简述了内循环三相生物流化床反应器的工作原理和工艺特性,综述了内循环三相生物流化床反应器的研究现状以及在废水处理领域中的应用实例,并分析了未来需要努力的方向。     

凹土复合滤料在三相生物流化床中的应用研究

利用凹土、粉煤灰、玻璃粉和漂珠为材料制得复合型凹土悬浮滤料,并作为填料运用于内循环三相生物流化床处理有机废水,同时考察曝气量和水力停留时间对COD和氨氮去除率的影响。结果表明,当曝气量为0.25m3/h时,COD和氨氮的去除率分别高达92.35%和95.13%;水力停留时间为2.0 h时,COD和氨氮的去除率分别高达91.5%和93.2%;所制得复合型凹土悬浮滤料性能良好。     

三相复合生物流化床反应器处理废水性能研究

提出和设计了一种新型的自充氧式复合生物流化床反应器，将该反应器应用于合成废水的处理，考察了反应器的挂膜以及停留时间、气水比，容积负荷等对COD去除率的影响，研究结果表明，该反应器在处理废水时，停留时间可达2h和1．5h,COD容积负荷提高到8．56和12．63kg/d.m^3，效率比同类反应器高1倍以上，气水比也有所下降，仅为32－34，具有停留时间短，能耗低，是一种高效的新型生物流化床反应器。     

提升管三相流化床内的气液传质系数

采用溶氧电极法测定了以牛顿和非牛顿流体为液相的提升管三相流化床的气液传质系数（ｋｌａ）。证明其值受床层流动特性的影响显著，那些能提供高气含率和增大液体循环速率的操作条件也有助于ｋｌａ的提高。通过引入广义雷诺数得出了计算牛顿和非牛顿流体内ｋｌａ的关联式     

生物流化床技术在水处理领域的研究进展

生物流化床有机结合了生物膜法与活性污泥法的优点,容积负荷大、处理效率高、应用范围广,在废水处理领域有良好的发展前景。介绍了生物流化床技术研究现状,综述了新型流化床工艺的发展情况,包括厌氧-好氧组合工艺、三相逆流化床、与生物膜结合以及芬顿Fenton流化床等新方向,展望了生物流化床技术的发展趋势。     

工业有机废水处理三重环流生物三相流化床成套技术

成果简介:三重环流生物三相流化床废水处理技术是生物膜法的一种工艺,通过附载在流化床内多孔载体粒子上的微生物膜发生一系列复杂的生物氧化反应,最终使废水中的有机质得到高效降解。本技术采用三重环流内构件可以明显降低反应器的能耗、提高溶氧效率、改善反应器的混合特性。由于独特的三相分离区设计,可大大延长生物颗粒的停留时间,实现污泥减量化程度达到70%~80%,废水处理的COD负荷为10~12 kg/m3·d,载体比表面积为2000~3000 m2/m3,生物浓度大于30 g/L,水力停留时间小于8 h,气水比为10~15∶1,吨水处理费用为0.8~1.0元。技术指标或产品…     

生物流化床处理废水的研究进展

生物流化床技术因具有处理效率高、容积负荷大、传质速度快、应用范围广等优点受到了广泛的关注。介绍了近年来国内外生物流化床技术在废水处理中的应用研究情况,并指出了生物流化床技术目前存在的主要问题及今后的发展方向。     

A three‐phase fluidized bed reactor in the combined anaerobic/aerobic treatment of wastewater

Aerobic degradation or polishing is an essential step in the combined anaerobic/aerobic treatment of wastewater. In this study, a type of porous glass beads was used for immobilization of microbial cells in a three‐phase aerobic fluidized bed reactor (AFBR) with an external liquid circulation. The effects of superficial gas and liquid velocities on bed expansion, solid and gas hold‐ups and specific oxygen mass transfer rate, k_La, were investigated. A tracer study showed that the mixing and flow pattern in the 8 dm³ reactor could be simulated by a non‐ideal model of two continuous stirred tank reactors (CSTRs) in series. By treating an effluent from an upflow anaerobic sludge blanket (UASB) digester, the distribution of suspended and immobilized biomass in the reactor as well as the kinetics of COD removal were determined. The specific oxygen mass transfer rate, k_La, at a superficial gas velocity of 0.7 cm s⁻¹ dropped by about 30% from 32 h⁻¹ in tap water to 22 h⁻¹ after a carrier load of 15% (v/v) was added. The measured k_La further dropped by about 20% to 18 h⁻¹ in the wastewater, a typical value of the bubbling fermenters with no stirring. Compared with the aerobic heterotrophs under optimum growth conditions, the microbes in this reactor which was fed with anaerobic effluent plus biomass behaved like oligotrophs and showed slow specific COD removal rates. This might be attributed to the presence of a significant amount of obligate anaerobes and facultative organisms in the aerobic reactor. This was confirmed by a relatively low intrinsic oxygen uptake rate of the microbial population in the reactor, 94 mg O₂ dm⁻³ h⁻¹ or 19 mg O₂g VS⁻¹ h⁻¹. © 1999 Society of Chemical Industry     

A mathematical model for a biological fluidized bed reactor

A physical model is given in the present report for representing a three-phase biological fluidized bed reaction system which consists of microorganism-coated particles, waste water and air. The system is assumed to be well fluidized. The physical model can be represented by two differential equations describing, respectively, the substrate axial dispersion and diffusion/reaction. Numerical values of the physical parameters are selected from the literature or estimated from semi-empirical equations. The governing system equations are solved by an iterative finite-difference scheme. The theoretical predictions are compared with several experimental measurements and the agreement between them found to be very good, validating the physical model reported here.     

Development of a three-phase fluidized bed reactor with enhanced oxygen transfer

A three-phase fluidized bed reactor (TFBR) was developed in this study with the objective to achieve high rates of oxygen transfer from the gas to the liquid phase in the presence of fluidized solid particles. With 2.9 m height, 0.605 m diameter, and a short residence time of 8 h, the TFBR is particularly suitable for industrial applications such as aerobic biodegradation of high-strength wastewaters including refractory compounds. Experiments with tap water and air show that the TFBR enables complete fluidization. With the water and air superficial velocities in the respective ranges of 0.005–0.203 and 0.8–2.0 cm/s, the volumetric oxygen transfer coefficient is 2.3 × 10⁻² s⁻¹, which is higher than that obtained in similar experimental studies on oxygen transfer carried out in the past. These results suggest that the developed TFBR could be very effective in industrial applications where short hydraulic time and high gas-to-liquid mass transfer rates are desirable.     

厌氧流化床处理红霉素废水的研究

研究了中温(33～35℃)条件下,厌氧流化床(AFB)反应器处理红霉素废水的运行特性.结果发现:进水COD为6 900 mg/L、HRT为4.4 h时,COD、BOD的去除率分别达到了76.6%、65.9%.最后利用Garrett-Sawyer关系式求出了难生物降解的有机物浓度,并利用Monod模型对实验结果进行了动力学分析,得出了红霉素废水中温条件下厌氧消化过程的基质降解规律.     

炼油废水生物流化床处理工业应用研究

介绍了一套有效体积为150m3、高径比为3.3的多导流筒生物流化床反应器工业试验装置,应用复合载体及生物菌群处理洛阳炼油厂炼油废水。用一级生化及一级沉淀两级工序代替原工艺六级组合工序。在反应温度为35℃,pH值为7,气液比为20∶1,水力停留时间为6.5h的优化试验条件下,使处理后废水中化学需氧量(COD)和氨氮(NH3-N)降解率分别大于85%和90%,即COD<100mg/L,NH3-N质量浓度<10mg/L,优于国家一级排放标准(GB8978—1996)。新工艺的占地面积、停留时间、产泥量及每吨水运行费用分别是老工艺的1/10、1/3、1/3和2/3。     

Liquid-Solid mass transfer in a slurry bubble column and a gas-liquid-solid three-phase fluidized bed

Mass transfer coefficients between particles and liquids in a slurry bubble column and a three-phase fluidized bed containing small size particles were obtained with two mass transfer systems: (1) K⁺ –Na⁺ ion-exchange in cation-exchange resin bead beds, including anion-exchange resin beads as inert particles; (2) zinc dissolution by HCl in zinc-plated glass bead beds, and in beds of non-plated glass beads. Operating parameters were gas velocity, liquid velocity, particle diameter, and particle concentration. The dependence of mass transfer coefficients on these parameters is discussed from the viewpoint of the energy supplied into the systems. Correlations of the experimental data using dimensionless groups are compared to previous correlations.     

Experimental study of the inverse fluidized bed biofilm reactor

A new apparatus, the inverse fluidized bed biofilm reactor, is described. Introduction of the so called inverse fluidized bed, in which low density particles covered by a biofilm are fluidized by downflow of the liquid, allows control of the biofilm thickness and provides a high oxygen concentration in the reacting liquid. Characteristics of the reactor were studied by carrying out two important biotechnological processes: aerobic wastewater treatment by a mixed bacterial culture, and ferrous iron oxidation by the bacteria Thiobacillus ferrooxidans. The bioreaction rates per unit volume of the reactor were up to 14 times higher than those in the equivalent airlift bioreactor. The structure of the liquid flow was determined by a tracer method.     

垂直管内三相流化床沸腾传热特性

研究了三相流化床沸腾传热的特性和影响传热系数的诸因素。在传热过程中，由于固体粒子的存在，强化了传热。以玻璃球粒子为固相的三相流化床沸腾传热系数，是相同条件下汽液两相流沸腾传热的二倍。以铜粒子为固相的三相流化床沸腾传热系数，是相同条件下汽液两相流沸腾传热系数的３倍。