Characteristics of critical solid-liquid separation and its effect on the performance of an anaerobic sequencing batch reactor treating municipal sludge

Solid-liquid separation and its type greatly affected the stability and performance of an anaerobic sequencing batch reactor (ASBR) for municipal sludge digestion. Flotation thickening occurred in the mesophilic ASBR, while solid-liquid separation in the thermophilic ASBR followed gravity thickening. Hydraulic retention times (HRT) and cycle period as well as type of thickening were key parameters governing sludge thickenability and critical solids accumulation. Thickened sludge bed volume was a critical operating variable in the ASBR with gravity thickening, which had poor performance because of the loss of thickened solids, and sludge interface disruption or instability of sludge bed due to internal gas evolution. A cyclic mutual effect between thickened volume and gas production was serious in gravity thickening, whereas it was insignificant in flotation thickening.     

生物法处理维生素 C 生产污水工艺研究

利用生物法,采用微生物化、物理化学化、好氧生化组合工艺处理维生素 C 生产系统污水,针对此种污水量大、有机物含量高、可生化性差、盐度高,结合生产过程中固体废弃物有待利用等特点,有效的引入了铁碳床微电解和类芬顿反应,对各步主要影响因素进行了研究.     

Impact of anaerobic lagoons on the performance of BOD and TSS removals at the Haspolat (Mia Milia) Wastewater Treatment Plant

One of the most common tests for the determination of strength and organic content of wastewater is the Biochemical Oxygen Demand (BOD). The capital of Cyprus, Nicosia has upgraded its wastewater treatment plant during the 2000s, providing a significant improvement in BOD and TSS treatment performances. These performances are tested by the data collected from 1994 until 2005 by using one-way ANOVA and least significant difference (LSD) tests. The tests showed significant difference (p < 0.05) in the means of the samples investigated before and after the upgrading of the treatment plant.Experimental results showed that the installation of innovative anaerobic lagoons was able to reduce the BOD and TSS concentrations to desirable values that fell within the discharge limits of national and international effluent standards. However, the limits for the reuse of effluent for irrigation purposes require more improvement on the treatment technology. The significant improvement in BOD removal percentages increased the BOD removal performance up to 93%, whereas the TSS removal performance increased to 84%.     

Effect of sonolysis on waste activated sludge solubilisation and anaerobic biodegradability

Activated sludge processes are key technologies in wastewater treatment. These biological processes produce huge amounts of waste activated sludge (WAS) or otherwise biosolids. Mechanical, thermal, and/or chemical WAS conditioning techniques have been proposed to reduce the sludge burden. Among the WAS treatments, the pre-treatment with ultrasound (US) is one of the most innovative processes. In many anaerobic digestion processes for the treatment of the sludge produced in wastewater treatment plants, the hydrolysis of the organic matter has been identified as the rate limiting step.This study is focused on the effect of US pre-treatment of WAS to the anaerobic digestion. Particle size reduction, Chemical Oxygen Demand (COD) solubilization and biodegradability by anaerobic digestion were monitored in order to find the optimal dose in US pre-treatment.The results show the better sonolysis conditions (US density, sonication time, specific energy) which can significantly improve the COD solubilisation and the anaerobic biodegradability.     

微波技术在石油工业中的应用研究进展

微波作为一种新的技术手段,已广泛应用于各个领域。作者综述了微波技术在石油工业领域的应用和研究状况,展望了微波技术在石油工业领域的应用前景。     

Mechanism of the effects of microwave irradiation on the relative volatility of binary mixtures

The use of microwave irradiation to enhance distillation processes has been reported recently. However, there is an ongoing debate in the scientific community on whether the observed enhancement is mainly a consequence of the shift of the “equilibrium” of vapor–liquid mass transfer. In this article, a developed instrument was used to determine the relative volatility of various binary mixtures under microwave irradiation. By comparing the relative volatility in the presence/absence of microwave irradiation, the shift of the “equilibrium” of vapor–liquid mass transfer was observed for certain binary mixtures under microwave irradiation. The effects of microwave irradiation on the relative volatility of binary mixtures (in addition to the mechanisms involved therein) were analyzed using the non‐equilibrium thermodynamic principle. The results demonstrate that differences in the dielectric properties, microwave field intensity, intermolecular forces, and boiling point play dominant roles in determining the effects of microwaves on the relative volatility. © 2016 American Institute of Chemical Engineers AIChE J, 63: 1328–1337, 2017     

Effect of microwave irradiation on the physical properties and structures of wool fabric

Microwaves are high frequency radio waves which are capable of penetrating many materials and causing heat to be generated in the process. To investigate the effect of microwave irradiation on the physical property, chemical structure, surface morphological structure, and fine structure of wool fabric, wool fabric was treated with microwave irradiation under variety of conditions in terms of the power and the time of microwave treatment. The breaking strength, breaking elongation, and whiteness of the treated wool fabric in different humid state were investigated. The structures of the untreated and treated wool were investigated with Fourier transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD), scanning electron microscopy (SEM), and Laser Raman spectroscopy (LRS). The results show that the physical properties of the treated wool fabrics were changed with microwave irradiation time and power. The chemical structure had not significant change. The surface morphological structure, the concentration of cystine S S bonds and crystallinity of the treated wool were changed. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

城市污泥中重金属存在形态、去除及稳定化研究进展

城市污水处理厂污泥产生量大,含有丰富的有机质、氮、磷、钾等农作物所需营养物质,但由于受重金属的污染使污泥无法直接农用。本文简述了城市污泥重金属的来源、特点及危害。重点论述了城市污泥中重金属去除和稳定方法,包括化学法（电化学法、化学试剂法）、生物法（微生物法、植物法、低等动物法）、物理法（超临界流体萃取、微波和超声）及联合技术。分析了各种方法处理污泥重金属过程中重金属的形态变化及其对处理效果的影响,对比各种方法的优缺点、影响因素及适用范围。指出污泥中重金属形态分布是影响去除效果的关键因素,污泥中重金属形态分布差异性大,且大部分重金属以稳定或相对稳定的状态存在,导致物理法和生物法去除效率较低,微生物和低等动物处理法相比植物法（备受时空限制）则表现出更好的适应性;电化学法对可氧化、可还原态分布的重金属都能起到较好的转化去除作用,但往往受由污泥向污泥液相中转移过程的控制,电损耗较突出;化学试剂浸提剂是目前效率较高的方法,但强酸环境常导致污泥营养物质流失和酸根离子累积,农用时容易板结而不利于污泥土地利用。因此,以土地利用为前提的条件下,将各种处理技术联合运用以提高污泥重金属去除率有待于进一步研究。     

Effect of industrial microwave irradiation on the physicochemical properties and pyrolysis characteristics of lignite

The surface functional groups and pyrolysis characteristics of lignite irradiated by microwave were comparatively studied to evaluate the feasibility of using industrial 915 MHz for lignite drying. The drying kinetics, micro structure, chemical functional groups, re-adsorption properties, and pyrolysis characteristics of the dried coal were respectively analyzed. Results indicated that for typical Chinese lignite studied in this paper, 915 MHz microwave drying was 7.8 times faster than that of the hot air drying. After industrial microwave drying, the sample possessed much higher total specific surface area and specific pore volume than that of air dried sample. The oxygen functional groups and re-adsorption ratio of microwave irradiated coal decreased, showing weakened hydrophilicity. Moreover, during the pyrolysis of the coal dried by hot air and microwave, the yield of tar largely increased from 1.3% to 8.5% and the gas production increased correspondingly. The composition of the tar was also furtherly analyzed, results indicated that Miscellaneous hydrocarbons (HCs) were the main component of the tar, and microwave irradiation can reduce the fraction of polycyclic aromatic hydrocarbons (PAHs) from 26.4% to 22.7%.     

污水污泥气化焦油热解特性的研究

利用热重分析方法,对由5种不同性质污泥在气化温度600℃、700℃和800℃下进行外热上吸式固定床空气气化时制得的9种污泥气化焦油的热解特性进行了研究.结果表明:9种气化焦油热解时均分为3个阶段,分别是水和低沸点有机物的挥发、有机物挥发分解以及残余物分解.污泥厌氧消化和污水处理工艺中的厌氧过程均使800℃下制得的气化焦油中低分子有机物含量增加,但对第二阶段挥发的轻质及重质非极性有机物总含量的影响很小,且使气化焦油的热解特性变差.气化温度对未消化污泥气化焦油热解时第一和第二阶段失重率的影响变化规律与消化污泥气化焦油的不同,且气化焦油的热解特性优于污泥热解焦油.热解动力学研究表明,9种气化焦油热解机理函数彼此不完全相同,且热解活化能均较低,具有良好的热解特性.     

Effect of microwave power irradiation on TiO2 nano-structures and binder free paste screen printed dye sensitized solar cells

Titanium dioxide (TiO₂) nanostructures (nanorods and nanoparticles) were prepared using a low-cost microwave irradiation method from a polyol medium of glycerol. Titanium glycerolate and TiO₂ powders were obtained in the glycerol medium for the first time with four different power densities (240?W, 480?W, 720?W, 960?W) of irradiation using a domestic microwave oven of 2.45?GHz, to understand the impact of power on morphology tuning. The structural and morphological features of the titanium glycerolate and TiO₂ powders were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and Raman spectra analysis. The TiO₂ was successfully used in the fabrication of photovoltaic devices and as a proof-of-concept binder free paste was prepared and successfully employed for photo-anode using screen printing on the fluorine-doped tin oxide substrate.     

Effect of sludge retention time in sludge holding tank on excess sludge production in the oxic‐settling‐anoxic (OSA) activated sludge process

The activated sludge process is a core technology in wastewater treatment plants. Excess sludge produced in the process must be treated and disposed of properly and may account for up to 60% of total plant operating cost. Therefore, it is necessary to develop new biological concepts to minimize excess sludge production. The oxic‐settling‐anoxic process (OSA process), a modified activated sludge process, may produce less excess sludge than the conventional activated sludge process. The effect of sludge retention time in the sludge holding tank of the OSA process on excess sludge yield has been studied. Four pilot‐scale activated sludge systems were employed, one of which was a conventional activated sludge process, and was used as the control system. The other three were OSA systems operated with different sludge retention times (5.5 h, 7.6 h, and 11.5 h) in the sludge holding tank. All systems were operated with synthetic wastewater for 7 months. Results showed that the three OSA processes with 5.5 h, 7.6 h, and 11.5 h sludge retention time reduced the excess sludge by 33%, 23% and 14%, respectively. Compared to the control process, chemical oxygen demand (COD) removal efficiency and effluent NH₃–N concentration were not significantly influenced, but total nitrogen (TN) removal efficiency decreased by 0–9%. Total phosphorus (TP) removal efficiency of OSA processes with 7.6 h and 11.5 h sludge retention time increased by 19%. Sludge settleability was excellent in the three OSA processes. No distinct shift in the diversity of the predominant species was found in microbial populations. We conclude that the OSA system could reduce excess sludge production. Results suggest 6–7 h sludge retention time would be optimal. Copyright © 2007 Society of Chemical Industry     

Enhanced Delignification of Wheat Straw by the Combined Effect of Hydrothermal and Fungal Treatments

Delignification is the crucial step for the conversion of lignocelluloses to biofuel. In this work, wheat straw delignification was enhanced by a two-step process, comprising hydrothermal and fungal treatments. Wheat straw was exposed to hydrothermal treatment at subcritical temperatures and then subjected to fungal treatment. Lignocellulose hydrolysis rate was significantly higher during the hydrothermal treatment compared to the slower fungal delignification. However, by-products of lignin degradation via hydrothermal treatment were re-deposited on the cellulose fibers as the substrate was cooled to room temperature. It is shown that post-treatment fungi can enhance delignification by degradation of the residual lignin by-products. The effect of fungal delignification of hydrothermally treated substrate was a function of temperature of the hydrothermal process. Compared to the hydrothermal treatment, the novel combined approach, proposed in this study, resulted in two-fold higher delignification and promises to be an effective method for delignified substrate preparation for conversion to biofuel.     

磁性纳米粒子类型和质量浓度对微波热解含油污泥的影响

鉴于传统微波吸收剂在协同微波热解含油污泥时存在热解效率较低、处理成本较高等问题,本文引入磁性纳米粒子作为新型微波吸收剂,探究了磁性纳米粒子种类和质量浓度在强化微波热解含油污泥中的作用效果和规律。实验结果表明：(1)在6种磁性纳米粒子(Zn Fe₂O₄、Fe₃O₄、Ni、Ni Fe₂O₄、γ-Fe₂O₃和Co₃O₄)中,添加Zn Fe₂O₄的实验组热解终温最高,为284℃,气、液相产物最多,分别为382m L和10.5m L;(2)当微波功率为800W、微波加热时间为20min时,添加纳米Zn Fe₂O₄实验组的热解终温在质量浓度5.0mg/g时最高;(3)随着纳米Zn Fe₂O₄质量浓度的增加,气相热解产物中H₂、CH...     

不同粒径厌氧氨氧化颗粒污泥的性状研究

通过实验比较了不同粒径Anammox颗粒污泥的物理性质和处理效果的差异。实验结果表明,Anammox颗粒污泥粒径的增大有助于减小颗粒污泥受到的不利条件的影响;粒径为0.5~1.0、1.0~1.5 mm及1.5 mm以上3组Anammox颗粒污泥的比反应速率(以N计)分别为0.52、0.62、0.55 g/(g·d)。综合考虑去除效果及稳定性,在本实验系统中,粒径在1.0~1.5 mm的Anammox颗粒污泥的综合性能最佳。     

Effect of microwave absorption properties and morphology of manganese dioxide on catalytic oxidation of toluene under microwave irradiation

A large number of studies had shown that the morphology of the sample had a significant effect on the microwave absorption properties and catalytic activity of the sample. Manganese dioxide with different morphologies was synthesized by hydrothermal method through different precursors. The effects of sample morphology and microwave absorption properties on the catalytic activity of the sample in conventional thermal and microwave fields were studied. The results indicated that compared with the conventional thermal field, the catalytic activity of the samples in microwave field were obviously improved, and the activation energy of the reaction were decreased. Compared with the conventional thermal field, the conversion of toluene in microwave thermal field of MnO₂(Ac), MnO₂(S) and MnO₂(N) increased by 59%, 42% and 12%, and the mineralization rate increased by 36%,11% and 2%, respectively, when the catalytic temperature was 150 °C. Compared with the traditional thermal field, the activation energy of the sample MnO₂(Ac) in the microwave field was reduced by 88.3 KJ. A series of characterization results showed that the sample MnO₂(Ac) had good catalytic activity in the microwave field was due to: MnO₂(Ac) had proper microwave absorption properties, large amount of surface functional groups, large specific surface area and rich pore structure. The analysis results of electromagnetic parameters showed that: the reason that the sample MnO₂(Ac) had good microwave absorption performance was that the MnO₂(Ac) had proper impedance matching, high attenuation constant and Debye dipole relaxation effect.     

Effect of process parameters on the energy requirement in ultrasonical treatment of waste sludge

Mechanical treatment methods are used as pre-treatment methods in order to enhance the efficiency of conventional sludge treatment processes and the sludge becomes more suitable for its complete treatment. The ultrasound is an alternative method among other methods, but because of its high energy requirement it should be optimized before utilization. This work gives the optimized parameters such as sonication time, sonication power (these parameters are the two factors which play part for energy calculations), type of sludge, cooling requirements and solid content in the sludge solution. Even if the previous researchers prefer to use the energy (specific energy usually), we have found out that both the sonication time and the sonication power have individual importance. For municipal sludge the main conclusion can be summarized as: “high power-short retention time” is more effective than “low power-long retention time”. As this phenomenon may alter from sludge to sludge, various combinations of power and retention time should be tried while keeping the volume small and the concentration below a certain level. The process should be performed at moderate temperatures and the efficiency increases if the sludge is as homogeneous as possible.     

Effect of the cationic starch on removal of Ni and V from crude oils under microwave irradiation

The effect of cationic starches on removal of nickel and vanadium from crude oils in the presence of microwaves was investigated. A series of cationic starches with different degrees of substitution synthesized by a microwave-dry process were used to remove nickel and vanadium from crude oils. The effects of a number of factors, such as the degree of substitution of cationic starches, microwave time and cationic starches dose on nickel and vanadium removal efficiencies from the crude oils were investigated. The results indicate that the higher the degree of cation substitution on the cationic starch, the greater the effect of electrostatic adsorption of the heavy metal positive ions. Sample CS4 (CS is the abbreviation of the cationic starch) had the best effect on nickel and vanadium removal efficiencies in cationic starch series. The optimum conditions for nickel and vanadium removal from crude oils were as follows: (a) amount of CS4 200 mg/L, (b) microwave power 300 W and (c) microwave time 5 min. Under these conditions, the removal efficiencies of nickel from Iranian and Shengli crude oils were 55% and 60%, respectively, and the removal efficiencies of vanadium were 76% and 79%, respectively.     

制革废水处理技术的对比与分析

就目前制革废水存在的问题,论述了制革废水的特点、发展与现状、危害以及处理难点,主要介绍了国内制革废水的处理工艺-传统活性污泥法、制革废水的全物化处理、氧化沟、SBR工艺和生物接触氧化法等,以及国外制革废水处理工艺-高效厌氧生物处理技术、膜分离技术和高级氧化技术。同时,对上述几种处理工艺的优缺点进行了比较分析,并对制革废水处理技术做了展望。     

改良型A~2/O工艺对低碳源城市污水的脱氮除磷效果

以城市污水为原水,考察了一种分点进水的改良型A2/O工艺的脱氮除磷效果。试验结果表明,原水按照6∶4的体积比分别进入厌氧池和缺氧池后,增加了缺氧池的碳源浓度,提高了该系统的脱氮效果。当进水中碳氮质量比平均为6.84、硝化液回流比为200%,CODCr、TN、NH3-N和TP的平均质量浓度分别为237.02、36.39、22.99和4.98mg/L时,出水CODCr、TN、NH3-N和TP的平均质量浓度分别为34.29、10.70、0.18和0.46mg/L,去除率分别为85.53%、70.60%、99.22%和90.76%。