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Biodegradation of bezafibrate by the activated sludge under aerobic condition:Effect of initial concentration,temperature and pH

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Emerging Contaminants 2016年第4期2卷 173-177页

作者： Qian Sui Pingping Yan Xuqi Cao Shuguang Lu Wentao Zhao Maozhe Chen State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process School of Resources and Environmental EngineeringEast China University of Science and TechnologyShanghai 200237China State Key Laboratory of Pollution Control and Resource Reuse College of Environmental Science and EngineeringTongji UniversityShanghai 200092China Beijing Key Laboratory for Emerging Organic Contaminants Control Tsinghua UniversityBeijing 100084China Shanghai Center for Energy-Saving and Emission-Reduction Co. LtdShanghai 200003China Journal of Water Purification Technology Shanghai 200082China

Lab-scale experiments were conducted to investigate the effect of initial concentration,temperature and pH on the removal of bezafibrate(BF)by activated sludge under aerobic condition.The results showed that adsorption of BF onto activated sludge was negligible,and biodegradation was the main removal mechanism of BF.The removal of BF in the aqueous phase by the activated sludge can be described by a pseudo-first-order reaction.The reaction rate constants had a negative relationship with the initial concentration of BF,and dramatically reduced from 0.050 to 0.007 h^-1,when the temperature dropped from 20℃to 10℃.Variation of pH between 5.0 and 9.0 did not have significant influence on the removal of BF,indicating a high adaptation of microorganism in the activated sludge responsible for BF degradation to a wide pH range.The findings of this study are helpful to improve the removal of pharmaceuticals during the wastewater treatment plants by selecting the appropriate process variables,and eventually eliminate their release to the environment.

关键词： PPCPs Biodegradation Sludge initial concentration Temperature pH

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Study on aerosol agglomeration using the airborne ultrasonic transducer

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Particuology 2023年第11期82卷 157-165页

作者： Yuxin Guo Guangxue Zhang Yunchao Li Hailin Gu Dingkun Yuan Maosheng Liu The Institute for Energy Engineering China Jiliang UniversityHangzhou310000China

Acoustic agglomeration technology use high-intensity acoustic field to make aerosol particles collide and condense rapidly. Existing studies have shown that 70%–90% of fine particles can be eliminated within minutes using compression drives and air-jet generators. Currently, there are limitations to the sound sources used. In this paper, an airborne ultrasonic transducer with a resonant frequency of 15 kHz is designed, followed by the corresponding numerical simulation and experiments for the evaluation of the vibration modal and sound pressure field. The sound pressure levels (SPL) of the open space and the agglomeration chamber can reach 150 dB and 156 dB, respectively. The agglomeration effect of water droplets, liquid phase smoke, solid phase smoke and mixed smoke is experimentally investigated, and the light transmittance rapidly increases from 8% to 60% within 4 s, 8 s, 5 s and 6 s, respectively. Agglomeration is also effective in the high-frequency range, and we infer that the acoustic wake effect is the predominant mechanism. The elimination effect is promoted with the increasing of SPL until the corresponding secondary acoustic effect is enhanced. Moreover, the agglomeration rate of higher concentration aerosol is significantly better than that of diluted aerosols in ultrasonic agglomeration process.

关键词： Acoustic agglomeration Airborne ultrasonic transducer Aerosol Sound pressure level initial concentration

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Evaluating the effects of granular and membrane filtrations on chlorine demand in drinking water

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Journal of Environmental Sciences 2009年第1期21卷 23-29页

作者： Veeriah Jegatheesan Seung Hyun Kim C. K. Joo GAO Baoyu School of Engineering James Cook University Townsville QLD 4811 Australia. Department of Civil Engineering Kyungnam University 631-701 Masan Korea Chilseo Water Treatment Plant Haman 637-940 Korea School of Environmental Science and Engineering Shandong University Jinan 250100 China

In this study, chlorine decay experiments were conducted for the raw water from Nakdong River that is treated by Chllseo Water Treatment Plant （CWTP） situated in Haman, Korea as well as the effluents from sand and granular activated carbon （GAC） filters of CWTP and fitted using a chlorine decay model. The model estimated the fast and slow reacting nitrogenous as well as organic/inorganic compounds that were present in the water. It was found that the chlorine demand due to fast and slow reacting （FRA and SRA） organic/inorganic substances was not reduced significantly by sand as well as GAC filters. However, the treated effluents from those filters contained FRA and SRA that are less reactive and had small reaction rate constants. For the effluents from microfiltration, ultrafiltration, and nanofiltration the chlorine demand because FRA and SRA were further reduced but the reaction rate constants were larger compared to those of sand and GAC filter effluents. This has implications in the formation of disinfection by products （DBPs）. If DBPs are assumed to form due to the interactions between chlorine and SRA, then it is possible that the DBP formation potential in the effluents from membrane filtrations could be higher than that in the effluents from granular media filters.

关键词： chlorine decay model initial concentration nitrogenous compounds organic and inorganic compounds reaction rate constants

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Humic acid transport in saturated porous media:Influence of flow velocity and influent concentration

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Journal of Environmental Sciences 2014年第12期26卷 2554-2561页

作者： Xiaorong Wei Mingan Shao Lina Du Robert Horton State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau Northwest A&F University Institute of Geographical Sciences and Natural Resources Research Chinese Academy of Sciences Department of Agronomy Iowa State University Ames IA 50011 USA

Understanding the transport of humic acids（HAs） in porous media can provide important and practical evidence needed for accurate prediction of organic/inorganic contaminant transport in different environmental media and interfaces. A series of column transport experiments was conducted to evaluate the transport of HA in different porous media at different flow velocities and influent HA concentrations. Low flow velocity and influent concentration were found to favor the adsorption and deposition of HA onto sand grains packed into columns and to give higher equilibrium distribution coefficients and deposition rate coefficients, which resulted in an increased fraction of HA being retained in columns.Consequently, retardation factors were increased and the transport of HA through the columns was delayed. These results suggest that the transport of HA in porous media is primarily controlled by the attachment of HA to the solid matrix. Accordingly, this attachment should be considered in studies of HA behavior in porous media.

关键词： Attachment Flow velocity Humic acid initial concentration Porous media Transport

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Characteristics of Flame Front Acceleration in Bend Channels under Different Conditions

Characteristics of Flame Front Acceleration in Bend Channels...

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2010(沈阳)国际安全科学与技术学术研讨会

作者： DONG Yong-xiang~1,XIA Chang-jing~2,DUAN Xiang-jie~1 (1.State Key Laboratory of Explosion Science and Technology,Beijing Institute of Technology,Beijing 100081,China 2.School of Mechanics & Civil Engineering,China University of Mining & Technology,Beijing 100083,China)

＜正＞The analysis on characteristics of flame front of propane-oxygen-air mixtures propagating in channels were carried out.Especially,the influences of the initial concentration and the bend shape of the combustible mixtures on the flame velocity were studied by experiments.The experimental results indicated that the flame velocity propagating through the bend increases as the mass percentage of propane ranges from 5.84%to 6.24%.It increases more than 20%for experimental setup A for the given analytical values.The existence of bend in channels plays an important role on the flame front acceleration of combustible mixture.By comparing the different bend shapes,the increment rate of velocity of flame front exists distinct obviously and the experimental setup B is the most valid than others to prohibit the flame acceleration in the bend.Thus the experimental results could provide reference for safety use of flame arresters in industry.

关键词： flame front propagation characteristics combustible mixture bend shape initial concentration flame arresters

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