WATER REMOVAL FROM SLUDGE IN A HORIZONTAL ELECTRIC FIELD

A new method for sludge dewatering was proposed, in which a horizontal electric field was applied in order to facilitate the dissipation of gases produced at electrodes and to keep the anode soaked in water during the dewatering process. The effects of operation conditions such as the magnitude of electric field strength, pH of aqueous phase, the pretreatment procedures including flocculation, freezing and heating on the water removal were examined, respectively. The morphological difference between the concentrated sludge produced by electrodewatering and by vacuum filtration was revealed with scanning electron microscopy, which shown that electrodewatering was effective in removing the capillary water in the sludge floc. At electric field strength of 1200 V/m, the sludge concentration could be increased from 3 to 8%(w/w), indicating that over 60% of water was removed from the sludge. Compared to those operated in a vertical electric field, the method described in the present study has the advantages in terms of high eficiency, simple structure and ease of operation.     

WATER REMOVAL FROM SLUDGE IN A HORIZONTAL ELECTRIC FIELD

A new method for sludge dewatering was proposed, in which a horizontal electric field was applied in order to facilitate the dissipation of gases produced at electrodes and to keep the anode soaked in water during the dewatering process. The effects of operation conditions such as the magnitude of electric field strength, pH of aqueous phase, the pretreatment procedures including flocculation, freezing and heating on the water removal were examined, respectively. The morphological difference between the concentrated sludge produced by electrodewatering and by vacuum filtration was revealed with scanning electron microscopy, which shown that electrodewatering was effective in removing the capillary water in the sludge floc. At electric field strength of 1200 V/m, the sludge concentration could be increased from 3 to 8%(w/w), indicating that over 60% of water was removed from the sludge. Compared to those operated in a vertical electric field, the method described in the present study has the advantages in terms of high eficiency, simple structure and ease of operation.     

OXYGEN TRANSFER IN HORIZONTAL PIPELINE AERATORS WITH NOZZLES

Horizontal pipeline and tubular loop aerators are of interest for fermentation and waste water treatment and are ideally suited for continuous processing. A major drawback is that these pipeline contactors invariably operate in the “elongated bubble and plug” regime in which the mass transfer rate is low. This article evaluates the performance of a horizontal pipeline aerator fitted with nozzles equispaced along its length to enhance mass transfer rates by promoting turbulence and augmenting effective interfacial area. Such devices can also be advantageously used in long pipe lines as in the case of treating waste while it is being transported. Pressure drop and overall liquid-side mass transfer coefficient data are reported as functions of liquid (water) and gas flow rates and nozzle size and spacing. It is shown that for all the conditions studied, k_La = 0.026(ΔP/L)^1.036 and that the pressure gradient is given by a simple correlation, provided an empirical parameter which characterises a nozzle is known. Preliminary investigations on the effect of surfactant ad the presence of suspended solids (size 75 μm) on mass transfer coefficient are also reported. Very high values of power dissipation can be achieved in such aerators without mechanically moving parts and high values of mass transfer coefficient can be realized.     

OXYGEN TRANSFER IN HORIZONTAL PIPELINE AERATORS WITH NOZZLES

Horizontal pipeline and tubular loop aerators are of interest for fermentation and waste water treatment and are ideally suited for continuous processing. A major drawback is that these pipeline contactors invariably operate in the “elongated bubble and plug” regime in which the mass transfer rate is low. This article evaluates the performance of a horizontal pipeline aerator fitted with nozzles equispaced along its length to enhance mass transfer rates by promoting turbulence and augmenting effective interfacial area. Such devices can also be advantageously used in long pipe lines as in the case of treating waste while it is being transported. Pressure drop and overall liquid-side mass transfer coefficient data are reported as functions of liquid (water) and gas flow rates and nozzle size and spacing. It is shown that for all the conditions studied, k_La = 0.026(ΔP/L)^1.036 and that the pressure gradient is given by a simple correlation, provided an empirical parameter which characterises a nozzle is known. Preliminary investigations on the effect of surfactant ad the presence of suspended solids (size 75 μm) on mass transfer coefficient are also reported. Very high values of power dissipation can be achieved in such aerators without mechanically moving parts and high values of mass transfer coefficient can be realized.     

陶瓷喷砂嘴的冲蚀磨损机理研究

以B4C和Al203／(W,Ti)C陶瓷材料制备喷砂嘴,以SiC和Al2O3作为冲蚀磨料进行了喷砂冲蚀试验。研究了陶瓷喷嘴材料的冲蚀磨损机理以及不同冲蚀磨科对陶瓷喷嘴冲蚀磨损的影响。结果表明：喷嘴材料的硬度对陶瓷喷嘴的冲蚀磨损起重要作用。在相同条件下,具有高硬度的B4C陶瓷喷砂嘴的磨损率较小,相对硬度较低的Al2O3/（W,Ti）C陶瓷喷嘴磨损率较大。B4C陶瓷喷嘴的主要磨损机理为脆性断裂,而Al2O3/（W,Ti）C陶瓷喷嘴的主要磨损机理为微观切削。冲蚀用磨科的硬度和粒度对陶瓷喷嘴的磨损也有一定的影响,磨料的硬度和粒度越大,陶瓷喷嘴的磨损速度加快。     

焦油含渣率分析及超滤机脱渣效率评价研究

采用离心分离和溶剂抽提相结合的方法测定煤焦油含渣率,运用激光粒度分析技术测定焦油渣粒度分布,并为焦油超滤系统的脱渣效率及>100μm粒级效率进行评价提供有效方法。     

APPLICATION OF HOT-FILM ANEMOMETRY TO AIR-WATER FLOW IN AERATED STIRRED TANKS

The subject of this paper is the evaluation of the applicability of constant temperature anemometry (CTA) with a modified version of Delhaye's method to aerated stirred tanks. A calibration technique that takes into account the variation in medium temperature was developed and verified experimentally. The directional sensitivity of the conical film probe was investigated in a streamline flow field as well as in the impeller discharge stream in an stirred tank.

The reliability of the setup and the technique was verified through the comparison of the vertical and radial velocity profiles of water in a stirred tank with those obtained from the literature. The directional response of the conical probe follows the cosine law for intersection angles smaller than 45° in a streamline flow field, but the directional sensitivity in the impeller discharge stream is rather poor, owing to the rolling characteristics of flow in this region. Due to the inability to detect bubbles smaller than the sensing element of the conical probe, the CTA usually gives lower values of local gas holdup. However, this discrepancy is considered to have no influence on the velocity measurement.     

煤气化装置捞渣机技术改造总结

分析河南煤业化工集团中原大化公司煤气化捞渣机在使用过程中出现的问题,有针对性地对捞渣机进行改造,收到良好效果。     

浸没式超滤工艺在给水处理中的应用研究

采用浸没式超滤系统取代传统工艺中的砂滤系统处理西江原水,对比了新工艺(混凝沉淀+浸没式超滤工艺)与传统工艺(混凝沉淀+砂滤工艺)的出水水质,考察了浸没式超滤系统的对COD、氨氮、浊度和颗粒物的去除,研究了试验期间系统跨膜压力(TMP)变化,最后考察了化学清洗对膜污染的控制。结果表明,混凝沉淀+浸没式超滤工艺出水CODMn和氨氮含量略高于混凝沉淀+砂滤工艺,但均达到了GB 5749-2006和CJ 94-2005要求;对浊度处理效果优于混凝沉淀+砂滤工艺;系统运行48 d,TMP从16 kPa升高到34.5 kPa;采用HCl和NaClO进行化学清洗,可有效控制膜污染。     

关于北京后海水体光照强度及沉水植物光补偿深度的研究

利用沉水植物治理水体污染是水环境恢复的重要措施之一。本文针对在北京市后海两次种植沉水植物而未获成功的状况,利用实测资料,建立了光照强度与水深、光补偿深度与透明度的关系模型,研究了水深与光补偿深度的关系。结论为：（1）光照强度与水深的关系为It=Ioe^-at,相关关系显著;（2）光补偿深度与透明度呈显著线性相关;（3）水体深度大于光补偿深度是造成沉水植物死亡的重要原因。     

应用热膜风速仪测定搅拌槽内气—液两相流的流体力学参数

开发应用了恒温热膜风速仪（简称ＣＴＡ）来测定搅拌槽内气－液两相流的局部气含率、液体的时均速度及脉动速度的均方根值。根据柱形热膜探头以及气－液搅拌槽内流体流动特性，改进了用电压概率密度法＾［１］划分气－液搅拌槽内气液两相信号的方法，在此基础上得到了局部气含率、液体的时均速度及脉动脉动速度均方根值的计算公式。研究了热膜探头偏角及流体介质温度变化对热膜风速仪测量精度的影响，并对流体介质温度的影响进行了校     

六箱一体式反应器水力流态及其脱氮除磷性能

采用有效容积为312L的模型对六箱一体式活性污泥反应器的流态特征及其脱氮除磷性能进行了试验研究。结果表明,周期性交替进水方式增强了反应器系统流态的完全混合性,在工艺上表现为通过反向进水完成混合液以及部分污泥回流。反应器具有良好的去除氮磷的性能,对NH3-N、COD、TN、TP的平均去除率分别为89％、75％、74％、90％,出水水质达到GB18918-2002中的一级标准。     

INTERPRETATION OF MICROMIXING EFFECTS ON FAST CONSECUTIVE-COMPETING REACTIONS IN SEMI-BATCH STIRRED TANKS BY A SIMPLE INTERACTION MODEL

A model is proposed for interpreting micromixing experiments in a semi-batch reactor. In these experiments, a fast consecutive-competing reaction system is used A + B → R, R + B → S, B being added either dropwise or as a pulse into an excess of A. A segregation index X_s = 2n_s/n_B0 is measured after completion of the reaction for various locations of the injection point. The macroscopic flow pattern is assumed to be known, essentially characterized by the recirculation time t_c. Micromixing then takes place within the cloud via a mechanism of interaction with the mean environment (IEM model, micromixing time t_m). Experimental results published by Barthole et al. (precipitation of barium sulphate) and Bourne et al. (diazo coupling) are successfully interpreted by this model. The influence of stirring speed, injection volume, concentration of species and mode of injection (pulse or dropwise) are especially well accounted for. This model provides a simple method for predicting the influence of mixing on selectivity in semi-batch reactors.     

EFFECT OF ACETIC ACID ON CO2 CORROSION OF CARBON STEEL IN VAPOR-WATER TWO-PHASE HORIZONTAL FLOW

The effect of acetic acid on the corrosion behavior of X 65 and C 1018 carbon steel in vapor-water two-phase stratified flow (Vsg: 2 m/s; Vsl: 0.1 m/s) at 2 bars total pressure, 1.54 bars CO₂ partial pressure, pH 5.5, and 80°C was studied in a low pressure-high temperature multiphase flow horizontal loop using electrochemical and mass loss techniques. The liquid phase is composed of 1% NaCl aqueous solution containing different concentrations of acetic acid (500 to 5000 ppm total acetic acid), and the gas phase is composed of CO₂-acetic acid-water vapor mixture. The corrosion rates, on both the top and bottom of the line, increase with increase in acetic acid concentration, which was attributed to the contribution of hydrogen ions by the free acetic acid to the cathodic reaction. Partial coverage of the metal surface by FeCO₃ on both the top and bottom of the line is reported to be responsible for the observed localized corrosion. Surface analysis investigated with SEM and XRD is reported.

A vapor-liquid equilibrium model was developed for the system studied.     

污水处理厂UASB污泥处理的试验研究

ＵＡＳＢ反应器已广泛用于处理各种废水，但用于处理污泥的方法尚未见有报道。本文讨论了常温下用活性污泥作种泥，培养颗粒污泥的可行性，并且得到了ＵＳＡＢ反应器处理污泥的运行参数。     

ORIGINAL TITLE: INTERPRETATION OF MICROMIXING EFFECTS ON FAST CONSECUTIVE-COMPETITIVE REACTIONS IN SEMI-BATCH STIRRED TANKS BY A SIMPLE INTERACTION MODEL

Liquid-liquid equilibrium data for two ternary systems were obtained. The experimental data were measured for cyclohexane-toluene-sulfolane at 17, 25 and 50°C, and for hexane-toluene-sulfolane at 18 and 25°C. The NTRL and UNIQUAC models were used to correlate the experimental results and to calculate the phase compositions of the ternary systems. The agreement between the experimental results and the fitted values was equally good with both of the models.     

螺旋桨搅拌槽中液体的流动结构

在直径１６００ｍｍ的平底柱形有机玻璃槽中，利用热膜风速仪测量了２个搅拌浆－槽体系中流体的时均速度，脉动速度的均方根值，湍流强度，纵向积分尺度，纵向微分尺度和能谱函数。研究了时均速度及湍流微结构在搅拌槽中的分布规律及搅抖转速的影响。     

顶置单喷嘴气化炉旋流场特征研究

受限旋转射流流场特征的研究对顶置单喷嘴气化炉的开发、结构优化以及长周期稳定运行有重要意义。本文对不同旋流数下顶置单喷嘴气化炉内的速度场和停留时间分布进行了实验研究。结果表明：随着旋流数的增加,切向旋转速度显著增加,气化炉内轴向速度衰减加快,回流区减小;气量一定时,随着旋流数的增加,气化炉内气体的最短停留时间显著增加,停留时间标准差减小。     

A COMPARATIVE ADSORPTION/BIOSORPTION OF PHENOL TO GRANULAR ACTIVATED CARBON AND IMMOBILIZED ACTIVATED SLUDGE IN A CONTINUOUS PACKED BED REACTOR

The potential use of Mowital B30H resin immobilized dried activated sludge as a substitute for granular activated carbon for removing phenol from aqueous solution was examined in a continuous packed bed reactor as a function of flow rate and inlet phenol concentration. The working sorption pH value was determined as 1.0 for both the sorbents, and packed bed sorption studies were performed at this pH value. The maximum specific uptakes, total adsorbed quantities, and total removals of phenol related to the effluent volumes were determined by evaluating the breakthrough curves obtained at different flow rates and different inlet phenol concentrations for each sorbent. At the lowest flow rate of 0.8 mL/min and at the inlet phenol concentration of 500 mg/L, the maximum specific uptakes and total removals of phenol were 84.0 mg/g and 27.6%, respectively, for granular activated carbon and 9.0 mg/g and 9.3%, respectively, for immobilized dried activated sludge. Data confirmed that total removals of phenol decreased with increasing flow rate and inlet phenol concentration for both immobilized dried activated sludge and granular activated carbon systems.