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Thermodynamic prediction and experimental investigation of short-term dynamic membrane formation in dynamic membrane bioreactors:Effects of sludge properties

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Journal of environmental Sciences 2019年第3期31卷 85-96页

作者： Zhenzhen Yu Yisong Hu Mawuli Dzakpasu Xiaochang C.Wang key lab of northwest water Resource Environment and Ecology MOE Xi'an University of Architecture and Technology International Science & Technology Cooperation Center for Urban Alternative water resources Development key lab of environmental Engineering Shaanxi Province

In dynamic membrane bioreactors(DMBRs), a dynamic membrane(DM) forms on a support material to act as the separation membrane for solids and liquids. In this study, batch filtration tests were carried out in a DMBR using nylon mesh(25 μm) as support material to filtrate sludge suspensions of variable properties from three different sources to evaluate the effects on the short-term DM formation process(within 240 min). Furthermore, the extended Derjaguin–Landau–Verwey–Overbeek(XDLVO) theory was applied to analyze the sludge adhesion and cohesion behaviors on the mesh surface to predict quantitative parameters of the short-term DM formation process(including initial formation and maturation stage). The filtration results showed that the order of the initial DM formation time(permeate turbidity waterability lability. Moreover, normal sludge(regarding settleability, dewaterability,flocculability, and extracellular polymeric substance) showed a more acceptable DM formation performance(short DM formation time, low permeate turbidity, and high permeate flux) than sludge with poor settleability, dewaterability and flocculability. The influence of sludge properties on the initial DM formation time corroborates the prediction of sludge adhesion behaviors by XDLVO theory. Additionally, the XDLVO calculation results showed that acid–based interaction, energy barrier, and secondary energy minimum were important determinants of the sludge adhesion and cohesion behaviors. Therefore, short-term DM formation process may be enhanced to achieve stable long-term DMBR operation through positive modification of the sludge properties.

关键词： Dynamic membrane bioreactor Dynamic membrane formation XDLVO theory Sludge properties Wastewater treatment

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Application of a hybrid gravity-driven membrane filtration and dissolved ozone flotation(MDOF)process for wastewater reclamation and membrane fouling mitigation

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Journal of environmental Sciences 2019年第7期31卷 17-27页

作者： Xin Jin Wei Wang Shuai Wang Pengkang Jin Xiaochang C.Wang Wushou Zhang Weijun An Yong Wang key lab of northwest water Resource Environment and Ecology MOE Xi'an University of Architecture and Technology Langzheng environmental Protection Technology Co. Ltd.

This study proposed a novel membrane filtration and dissolved ozone flotation integrated(MDOF) process and tested it at pilot scale. Membrane filtration in the MDOF process was operated in gravity-driven mode, and required no backwashing, flushing, or chemical cleaning. Because ozone was added in the MDOF process, ozonation, coagulation, and membrane filtration could occur in a single reactor. Moreover, in situ ozonation occurred in the MDOF process, which differs from the conventional pre-ozonation membrane filtration process. Significant enhancement of turbidity removal was further achieved through the addition of membrane filtration. Membrane fouling was mitigated in the MDOF process compared to the MDAF process. In situ ozonation in the MDOF process decreased the fluorescence intensity and transformed the high MW dissolved organics into small MW compounds. For the fouling layer, the extracellular polymeric substance(EPS) contents and cake layer morphology were analyzed. The results indicated that the contents of EPS decreased. Furthermore, a thinner and more loosely structured cake layer formed in the MDOF process. Because coagulation and ozonation occurred simultaneously in a single reactor, the generation of hydroxyl radicals was enhanced through the catalytic effect of Al-based coagulants on ozone decomposition, which further alleviated membrane fouling in the MDOF process.

关键词： Dissolved ozone flotation Gravity-driven membrane filtration Membrane fouling In situ ozonation

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Dynamic membrane bioreactor performance enhancement by powdered activated carbon addition:Evaluation of sludge morphological,aggregative and microbial properties

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Journal of environmental Sciences 2019年第1期31卷 73-83页

作者： Zhenzhen Yu Yisong Hu Mawuli Dzakpasu Xiaochang C.Wang Huu Hao Ngo key lab of northwest water Resource Environment and Ecology MOE Xi'an University of Architecture and Technology International Science & Technology Cooperation Center for Urban Alternative water resources Development key lab of environmental Engineering Centre for Technology in water and Wastewater School of Civil and Environmental Engineering University of Technology Sydney

The effects of powdered activated carbon(PAC) addition on sludge morphological, aggregative and microbial properties in a dynamic membrane bioreactor(DMBR) were investigated to explore the enhancement mechanism of pollutants removal and filtration performance. Sludge properties were analyzed through various analytical measurements. The results showed that the improved sludge aggregation ability and the evolution of microbial communities affected sludge morphology in PAC-DMBR, as evidenced by the formation of large, regularly shaped and strengthened sludge flocs. The modifications of sludge characteristics promoted the formation process and filtration flux of the dynamic membrane(DM) layer. Additionally, PAC addition did not exert very significant influence on the propagation of eukaryotes(protists and metazoans)and microbial metabolic activity. High-throughput pyrosequencing results indicated that adding PAC improved the bacterial diversity in activated sludge, as PAC addition brought about additional microenvironment in the form of biological PAC(BPAC), which promoted the enrichment of Acinetobacter(13.9%), Comamonas(2.9%), Flavobacterium(0.31%) and Pseudomonas(0.62%), all contributing to sludge flocs formation and several(such as Acinetobacter) capable of biodegrading relatively complex organics. Therefore, PAC addition could favorably modify sludge properties from various aspects and thus enhance the DMBR performance.

关键词： Dynamic membrane bioreactor Powdered activated carbon Sludge property Filtration performance Wastewater treatment Microbial community

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On the effect of Fe(Ⅲ) on proliferation of Microcystis aeruginosa at high nitrate and low chlorophyll condition

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Journal of environmental Sciences 2017年第2期29卷 105-110页

作者： Rong Chen Zhen Lei Jiayuan Ji Xiaochang Wang Yu-You Li Yuan Yang Lu Zhang Tao Xue key lab of northwest water Resource Environment and Ecology MOE Xi'an University of Architecture and Technology Department of Civil and environmental Engineering Graduate School of Engineering Tohoku University

The impact of Fe concentrations on the growth of Microcystis aeruginosa in aquatic systems under high nitrate and low chlorophyll conditions was studied. The responses of cell density,total and cell chlorophyll-a intracellular Fe content and organic elemental composition of M.aeruginosa to different concentration gradients of Fe（Ⅲ） in the solutions were analysed. The results showed that the proliferation speeds of M. aeruginosa were：（1） decelerated when the Fe（Ⅲ） concentration was lower than 50 μg/L in the solutions,（2） promoted and positively related to the increase of Fe（Ⅲ） concentration from 100 to 500 μg/L in the solutions over the experimental period, and（3） promoted in the early stage but decelerated in later stages by excess adsorption of Fe by cells when the Fe（Ⅲ） concentration was higher than 500 μg/L in the solutions. The maximum cell density, total and cell chlorophyll-a were all observed at 500 μg Fe（Ⅲ）/L concentration. The organic elemental composition of M. aeruginosa was also affected by the concentration of Fe（Ⅲ） in the solutions, and the molecular formula of M. aeruginosa should be expressed as C7–7.5H14O0.8–1.3N3.5–5according to the functions for different Fe（Ⅲ）concentrations. Cell carbon and oxygen content appeared to increase slightly, while cell nitrogen content appeared to decrease as Fe（Ⅲ） concentrations increased from 100 to 500 μg/L in the solutions. This was attributed to the competition of photosynthesis and nitrogen adsorption under varying cell Fe content.

关键词： High nitrate Low chlorophyll Fe Microcystis aeruginosa Cell chlorophyll a Organic element composition

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A Novel 3D Supramolecular Framework of Poly[(5-(oxidediphenylphosphino)isophthalate)zinc(Ⅱ)]: Syntheses and Structure

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Chinese Journal of Structural Chemistry 2014年第8期33卷 1199-1206页

作者：梅崇珍李海华孟瑞静梅世乐熊翰林 Institute of environmental and Municipal Engineering North China University of Water Conservancy and Electric Power key lab. of northwest water resources and environment ecology of moe at Xi’an University of Technology

A novel metal-organic framework, namely [Zn（C20H13OsP）]n （1）, has been hydro- thermally synthesized through the reaction of 5-（oxidediphenylphosphino）isophthalic acid （H2L） with Zn（II） salt. The title compound crystallizes in monoclinic, space group P21/c with a = 11.0966（10）, b = 14.5651（14）, c = 14.7311（15） A, fl = 130.022（6）°, C2oH13OsPZn, Mr = 429.64, V= 1823.3（3） ./k3, Dc = 1.565 g/cm3, F（000） = 872, g = 1.463 mm＂1, S = 1.054 and Z = 4. The final R = 0.0270 and wR = 0.0739 for 2769 observed reflections with 1 〉 20（/）. In the title complex, the Zn2（CO2）2 binuclear clusters are linked by L2- ligands to result in a pillared layer structure in the bc plane, which is a （4,4）-net composed of helical chains with opposite chirality by sharing Zn2（CO2）2 units. Adjacent＇layers are further associated together through Zn-O bonds involving the metal center and the oxygen atom of P=O group to achieve a 3D architecture, in which one-dimensional qua＆angled channel displays the interweaving of two pairs of coaxial double-helical chains with opposite chirality. The luminescence property and thermogravimetric analysis of the title complex were investigated.

关键词： 5-（oxidediphenylphosphino）isophthalic acid coaxial double-helical chains,opposite chirality

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Evaluation of self-healing ability of Ce-V conversion coating on AZ31 magnesium alloy

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Journal of Magnesium and Alloys 2016年第3期4卷 230-241页

作者： Xiao Jiang Ruiguang Guo Shuqin Jiang key lab of northwest water resources Environment and EcologyMinistry of EducationXi’an University of Architecture and TechnologyXi’an 710055China

This study investigated the influence of cerium nitrate in vanadate solutions on the properties of Ce–V conversion coatings on AZ31 magnesium alloys,and evaluated the self-healing behavior of the Ce–V conversion coating for AZ31 magnesium alloy.The results showed that the additions of cerium nitrate prevented pentavalent vanadium from reducing to tetravalent vanadium in the coatings during conversion reaction process.Adding appropriate cerium nitrate to vanadate solution led to a thicker coating with a more compact CeVO_(4) layer.The corrosion behavior of the Ce–V conversion coating was investigated by the electrochemical tests and the scratch immersion test in 3.5 wt.%NaCl solution.The self-healing ability of the coating was confirmed from all tests.The surface analysis revealed that the self-healing effect of the Ce–V conversion coating was only provided by the release and migration of vanadium compounds.

关键词： AZ31 magnesium alloy Vanadium Cerium Self-healing Electrochemical impedance spectroscopy

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Mechanisms of ultraviolet disinfection and chlorination of Escherichia coli： Culturability, membrane permeability,metabolism, and genetic damage

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Journal of environmental Sciences 2018年第3期30卷 356-366页

作者： Limei Xu Chongmiao Zhang Pengcheng Xu Xiaochang C.Wang International Science and Technology Cooperation Center for Urban Alternative water resources Development China key laboratory of northwest water Resource Environment and Ecology MOE China Engineering Technology Research Center for Wastewater Treatment and Reuse Shaanxi Province China School of environmental and Municipal Engineering Xi'an University of Architecture and Technology Xi'an 710055 China

Traditional culture methods may underestimate the tolerance of microorganisms to disinfectants because of the existence of viable but nonculturable or sublethally injured cells after disinfection.The selection of a strict method is crucial for the evaluation of disinfection performance.The actions of 2 typical disinfectants–ultraviolet（UV）and chlorine–on the fecal indicator Escherichia coli were investigated by the detection of culturability,membrane permeability,metabolic activity,deoxyribonucleic acid（DNA）,and messenger ribonucleic acid（m RNA）.During UV disinfection,the irreversible damages in the cell membrane and cellular adenosine triphosphate（ATP）were negligible at low UV doses（80 m J/cm^2）.However,membrane permeability was damaged at low doses of chlorine（5 mg/L）,leading to leakage of cellular ATP.Our study showed that a slight lesion in DNA was detected even at high doses of UV（400 m J/cm^2）and chlorine（5 mg/L）treatments.The decay of m RNA was more rapid than that of DNA.The degradation level of m RNA depended on the choice of target genes.After exposure to 50 m J/cm^2UV dose or 5 mg/L chlorine for30 min,the DNA damage repair function（Rec A m RNA）was inhibited.The m RNA involved in the DNA damage repair function can be a potential indicator of bacterial viability.

关键词： UV Chlorination Membrane damage Adenosine triphosphate DNA mRNA

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Bamboo charcoal enhances cellulase and urease activities during chicken manure composting:Roles of the bacterial community and metabolic functions

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Journal of environmental Sciences 2021年第10期33卷 84-95页

作者： Yanan Yin Chao Yang Jingrui Tang Jie Gu Haichao Li Manli Duan Xiaochang Wang Rong Chen key laboratory of northwest water Resource Environment and EcologyMOESchool of Environmental and Municipal EngineeringXi’an University of Architecture and TechnologyXi’an 710055China International S&T Cooperation Center for Urban Alternative water resources Development Xi’an University of Architecture and TechnologyXi’an 710055China College of resources and environmental Sciences Northwest A&F UniversityYanglingShaanxi 712100China Department of environment Faculty of Bioscience EngineeringGhent University9000 GhentBelgium State key laboratory of Eco-hydraulics in northwest Arid Region of China Xi’an University of TechnologyXi’an 710048China

Microbial enzymes are crucial for material biotransformation during the composting process.In this study,we investigated the effects of adding bamboo charcoal(BC)(i.e.,at 5%,10%,and 20%corresponding to BC5,BC10,and BC20,respectively)on the enzyme activity levels during chicken manure composting.The results showed that BC10 could increase the cellulose and urease activities by 56%and 96%,respectively.The bacterial community structure in BC10 differed from those in the other treatments,and Luteivirga,Lactobacillus,Paenalcaligenes,Ulvibacter,Bacillus,Facklamia,Pelagibacterium,Sporosarcina,Cellvibrio,and Corynebacterium had the most important roles in composting.Compared with other treatments,BC10 significantly enhanced the average rates of degradation of carbohydrates(Dxylose(40%)andα-D-lactose(44%))and amino acids(L-arginine(16%),L-asparagine(14%),and L-threonine(52%)).We also explored the associations among the bacterial community and their metabolic functions with the changes in the activities of enzymes.Network analysis demonstrated that BC10 altered the co-occurrence patterns of the bacterial communities,where Ulvibacter and class Bacilli were the keystone bacterial taxa with high capacities for degrading carbon source,and they were related to increases in the activities of cellulase and urease,respectively.The results obtained in this study may help to further enhance the efficiency of composting.

关键词： Bacterial community Carbon utilization Cellulase Composting Urease

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Effect of non-point source pollution on water quality of the Weihe River

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International Journal of Sediment Research 2011年第1期26卷 50-61页

作者： LI Jiake~(1*),LI Huaien~2,SHEN Bing~3,and LI Yajiao~4 Xi’an University of Technology,key lab of northwest water Resource and environment ecology of moe,Xi’an,Shaanxi,710048,China Xi’an University of Technology,key lab of northwest water Resource and environment ecology of moe,Xi’an,Shaanxi,710048,China, Xi’an University of Technology,key lab of northwest water Resource and environment ecology of moe,Xi’an,Shaanxi,710048,China, School of Architecture and Civil Engineering,Xi’an University of Science and Technology,Xi’an,Shaanxi, 710054,China, Associate Prof. Dr. Xi'an University of Technology Key Lab of Northwest Water Resource and Environment Ecology of MOE Xi'an Shaanxi 710048 China Prof. Dr. Xi'an University of Technology Key Lab of Northwest Water Resource and Environment Ecology of MOE Xi'an Shaanxi 710048 China Dr. School of Architecture and Civil Engineering Xi'an University of Science and Technology Xi'an Shaanxi 710054 China

Non-point source pollution is an important factor that affects the water quality of the Weihe River.To study the effect of the pollution on the water quality of the Weihe River,five flood events and three normal discharge events during non-flood period were monitored from July to December in 2006,at the Lin-tong section.In order to identify how sediment influenced the water quality of the river,raw and supernatant samples taken from the monitored events were analyzed.Supernatant samples were siphoned from 5 cm below the water surface of the raw samples at the lab afterwards the raw samples were shaken up and laid for 30 minutes in the beakers.The results indicated that:1) The concentrations of SS,COD,TP and TN in the raw samples from flood events were higher than those from normal discharge events.The higher values of the COD,TP and TN in the raw samples resulted from natural humic matters in surface soil.2) The load transport rate of analyzed water quality indexes increased gradually to its maximum and then drop down,matching that in the discharge hydrograph.The concentrations of SS,NH-N,NO-N,NO-N,COD,and TP in the raw samples increased initially and then decreased,while the concentration of dissolved orthophosphate and TN in the raw samples decreased gradually and then increased.The peak time of concentration and load transport rate of SS as well as COD,TP and TN in the raw samples were close to or lagged behind the time of peak flow. Generally,the peak time of concentration and load transport rate of dissolved orthophosphate, dissolved total-phosphate,NH-N,NO-N,and NO-N occurred prior to the time of peak flow.3) The mean concentration method was used to calculate the NPS pollution load at Lin-tong section,and the results are credible.In 2006,the proportions of the NPS pollution load to the total load for COD,TP, TN and inorganic nitrogen were more than 30%.

关键词： Weihe River Non-point source pollution Flood Monitoring Load

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Risk Response Strategy Research of water and Sediment Regulation System running schemes in the yellow river

Risk Response Strategy Research of Water and Sediment Regula...

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第26届中国控制与决策会议

作者： Zhao Jing Yixin Zhao Huang Qiang Wenjun Tian Key Lab of Northwest Water Resources and Environment Ecology of MOE at Xi'an Hydrology Bureau of The Yellow River Conservancy Commission Henan water & Power Engineering Consulting Co.Ltd

Based on the sensitivity analysis on risk factors, the risk response strategies were consequently proposed, and the basic theories of the strategies were introduced in detail. The main procedure of the strategies includes listing the risks to cope with, estimating the main risk resistance capability, developing the risk consistent measures and formulating alternative risk response strategies. Some principles were followed during the strategy formulation such as appropriateness, timeliness, consensus agreement, clear responsibility and optimization. Risk response strategies can be put forward from the following several aspects with consideration: risk management program, risk control strategy, project control, labor control and management control. To select risk response strategies, the risk loss as well as the nature and composition of the cost needs to be analyzed considerately. Finally, the countermeasures for risk mitigation were suggested, namely risk transfer strategies and risk retention measures.

关键词： Risk factors Risk response strategies water and sediment hazard

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