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Nitrogen removal via nitrite from municipal landfill leachate

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Journal of environmental Sciences 2009年第11期21卷 1480-1485页

作者： WU Lina, PENG Chengyao, ZHANG Shujun, PENG Yongzhen key laboratory of {2. for Water Quality Science and Water {2. Recovery Engineering, {2. university of Technology, {2. 10012., China. [a]key laboratory of {2. for Water Quality Science and Water {2. Recovery Engineering Beijing University of Technology Beijing 100124 China

A system consisting of a two-stage up-flow anaerobic sludge blanket （UASB）, an anoxic/aerobic （A/O） reactor and a sequencing batch reactor （SBR）, was used to treat landfill leachate. During operation, denitrification and methanogenesis took place simultaneously in the first stage UASB, and the effluent chemical oxygen demand （COD） was further removed in the second stage UASB. Then the denitrification of nitrite and nitrate in the returned sludge by using the residual COD was accomplished in the A/O reactor, and ammonia was removed via nitrite in it. Last but not least, the residual ammonia was removed in SBR as well as nitrite and nitrate which were produced by nitrification. The results over 12. d （60 d for phase I and 60 d for phase II） were as follows： when the total nitrogen （TN） concentration of influent leachate was about 2.00 mg/L and the ammonia nitrogen concentration was about 2.00 mg/L, the shortcut nitrification with 85%-90% nitrite accumulation was achieved stably in the A/O reactor. The TN and ammonia nitrogen removal efficiencies of the system were 98% and 97%, respectively. The residual ammonia, nitrite and nitrate produced during nitrification in the A/O reactor could be washed out almost completely in SBR. The TN and ammonia nitrogen concentrations of final effluent were about 39 mg/L and 12.mg/L, respectively.

关键词： short-cut nitrification up-flow anaerobic sludge blanket anoxic/aerobic reactor sequencing batch reactor landfill leachate

Map layer integration model for automatic mapping of mineral resource potentials

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中国有色金属学会会刊：英文版 2005年第S1期15卷 193-196页

作者： ZHAO Wen-ji~1, GONG Hui-li~1, LI xiao-juan~1, GONG Zhao-ning~1, ZHANG Song-mei~2. LI Jing~2.(1. capital normal university, The key Lab of {2. {2. and gis, beijing 10003., China 2. beijing normal university, beijing 13002., China) capital normal Univ Key Lab Environm Beijing 100037 Peoples R China gis Beijing 100037 Peoples R China beijing normal Univ Beijing 130026 Peoples R China

A map layer integration model for automatic mapping of mineral resource potentials, called evidence theory model, was proposed. This model can be applied to automatically generate mineral resource potential map in {2.. According to the geological data of the district from Duolanasayi to Ashele in northern Xinjiang Uygur Autonomous Region, the author applied evidence theory model and combined ore-forming belief model to mineral resource target selection.

关键词： mineral resource potential evidence theory model mass of evidence model synthetic ore-forming belief model basic probability function

A HIGH-ORDER FINITE DIFFERENCE METHOD FOR UNSTEADY CONVECTION-DIFFUSION PROBLEMS WITH SOURCE TERM

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Journal of Hydrodynamics 1999年第2期11卷 97-102页

作者： Yang Zhi-feng Wang Xuan(State key laboratory of {2. Simulation and Pollution Control, Institute of {2.al Sciences, beijing normal university, beijing 100875, P. R. China.) beijing normal Univ Beijing China

The convection and diffusion are the basic processes in fluid flow and heat& mass transfer. The upwind and evolution functions for the convection term are introduced to give a comprehensive transformation to one-dimensional unsteady convection-diffusion equation involving source term. The corresponding compact fourth-order finite difference methed is developed. With the trans formation, the authors overcome the difficultyin dealing with the convection term, and the high-order expression for the convection-diffusion term can be conveniently obtained. The proposed difference scheme with thefourth-order accuracy and unconditional stability can fully reflect the upwind and evolutioneffects of the convection. The calculated results show that the errors of the referencescheme are 600 or 6000 times those of the proposed scheme for the same computationalgrid. With the one time decrease of the space grid, the errors of the proposed scheme andthe reference scheme reduce about 2. times and 2.times respectively. It is evident that theaccuracy of the proposed scheme is remarkably higher than that of the reference scheme.

关键词： convection-diffusion compact difference method comprehensive transformation unsteady computational fluid dynamics

Characteristics of energy dissipation in hyperconcentrated flows

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International Journal of Sediment Research 2008年第4期23卷 387-397页

作者： An-ping SHU 1,Qing-quan LIU2.Yu-jun YI 3,and Zhi-dong ZHANG 41 Assoc.Prof.,School of environment,key {2. of Water and Sediment Sciences of Ministry of Education,{2. normal university,{2. 100875,China2.Prof.,Institute of Mechanics,Chinese Academy of Sciences,{2. 100080,China3 Lecturer,Dr.,School of environment,{2. normal university,{2. 100875,China4 Graduate student,School of environment,{2. normal university,{2. 100875,China [a]Assoc. Prof. School of environment key laboratory of Water and Sediment Sciences of Ministry of Education beijing normal {2. beijing 100875 China [b]Prof. Institute of Mechanics Chinese Academy of Sciences beijing 100080 China [c]Lecturer Dr. School of environment beijing normal {2. beijing 100875 China. The project is supported by the National Natural Science Foundation of China (Grant No. 10672.2.) [d]Graduate student School of environment beijing normal {2. beijing 100875 China

An equilibrium equation for the turbulence energy in sediment-laden flows was derived on the basis of solid–liquid two-phase flow theory. The equation was simplified for two-dimensional, uniform, steady and fully developed turbulent hyperconcentrated flows. An energy efficiency coefficient of suspended-load motion was obtained from the turbulence energy equation, which is defined as the ratio of the sediment suspension energy to the turbulence energy of the sediment-laden flows. laboratory experiments were conducted to investigate the characteristics of energy dissipation in hyperconcentrated flows. A total of 115 experimental runs were carried out, comprising 70 runs with natural sediments and 45 runs with cinder powder. Effects of sediment concentration on sediment suspension energy and flow resistance were analyzed and the relation between the energy efficiency coefficient of suspended-load motion and sediment concentration was established on the basis of experimental data. Furthermore, the characteristics of energy dissipation in hyperconcentrated flows were identified and described. It was found that the high sediment concentration does not increase the energy dissipation; on the contrary, it decreases flow resistance.

关键词： Hyperconcentrated flows Turbulence energy Efficiency coefficient Energy dissipation

Cloning and sequencing of nifBHDKENX genes of Paenibacillus massiliensis T7 and its nif promoter analysis

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Science China(Life Sciences) 2006年第2期49卷 115-122页

作者： ZHAO Hongxin1,2.3, XIE Baoen2.& CHEN Sanfeng1,2.1. State key laboratory for Agrobiotechnology and Biological School, China Agricultural {2., {2. 100094, China 2. key laboratory for Agro-Microbial resource and Application of Agriculture Ministry, China Agricultural {2., {2. 100094, China 3. Chemical and Biological School, ShenYang normal {2., Shenyang 110034, China 1. State key laboratory for Agrobiotechnology and Biological School China Agricultural University Beijing 100094 China 2. key laboratory for Agro-Microbial {2. and Application of Agriculture Ministry China Agricultural University Beijing 100094 China 3. Chemical and Biological School ShenYang Normal University Shenyang 110034 China

A 32. bp of nifH fragment was PCR amplified from Paenibacillus massiliensis T7 using the universal degenerate primers. The PCR-amplified nifH fragment was labeled with DIG; then used as a probe in Southern blot analysis. Southern blot result showed that there were two positive signals, indicating that there might be two copies of nifH in P. massiliensis T7. A total of 102.4 bp DNA sequence containing purD; nifBHDKENX was obtained by five rounds of inverse-PCR amplification. The predicted proteins of nifBHDKENX had high homology with those from other nitrogen-fixing bacteria. Only one putative σ[54]-dependent promoter sequence was detected upstream of the nifB gene; nifBHDKENX were likely to be organized in one operon. Assays of β-galactosidase activity of P. massiliensis T7PB carrying a nifB-lacZ fusion under different concentrations of NH4 [+]; O2.showed that the expression of nifB-lacZ was strongly inhibited by O2.

关键词： Paenibacillus massiliensis T7, nifBHDKENX, nifB-lacZ, inverse-PCR.

Biodegradation of polycyclic aromatic hydrocarbons in sediments from the Daliao River watershed, China

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Journal of environmental Sciences 2009年第7期21卷 865-871页

作者： QUAN Xiangchun, TANG Qian, HE Mengchang, YANG Zhifeng, LIN Chunye, GUO Wei State key Joint laboratory of {2.al Simulation and Pollution Control, School of {2., beijing normal university, beijing 100875, China. [a]State key Joint laboratory of {2.al Simulation and Pollution Control School of Environment Beijing Normal University Beijing 100875 China

The Daliao River, as an important water system in Northeast China, was reported to be heavily polluted by polycyclic aromatic hydrocarbons （PAHs）. Aerobic biodegradations of four selected PAHs （naphthalene, phenanthrene, fluorene and anthracene） alone or in their mixture in river sediments from the Daliao River water systems were studied in microcosm systems. Effects of additional carbon source, inorganic nitrogen and phosphorus, temperature variation on PAHs degradation were also investigated. Results showed that the degradation of phenanthrene in water alone system was faster than that in water-sediment combined system. Degradation of phenanthrene in sediment was enhanced by adding yeast extract and ammonium, but retarded by adding sodium acetate and not significantly influenced by adding phosphate. Although PAHs could also be biodegraded in sediment under low temperature （5~C）, much lower degradation rate was observed. Sediments from the three main streams of the Daliao River water system （the Hun River, the Taizi River and the Daliao River） demonstrated different degradation capacities and patterns to four PAHs. Average removal rates （15 or 19 d） of naphthalene, phenanthrene, fluorene and anthracene by sediment were in the range of 0.062.0.087, 0.005-0.066, 0.008- 0.016 and 0-0.059 mg/（L.d）, respectively. As a result, naphthalene was most easily degraded compound, anthracene was the hardest one. In multiple PAHs systems, the interactions between PAHs influenced each PAH biodegradation.

关键词： biodegradation the Daliao River microcosm polycyclic aromatic hydrocarbon sediment

Quenched moderate deviations principle for random walk in random environment

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Science China Mathematics 2010年第8期53卷 1947-1956页

作者： HONG WenMing 1 & WANG HuaMing 1,2.1 key laboratory of Mathematics and Complex Systems of Ministry of Education & School of Mathematical Sciences,{2. {2. university,{2. 100875,China 2.Department of Basic Courses,Business College,{2. Union university,{2. 10002.,China 1. key laboratory of Mathematics and Complex Systems of Ministry of Education & School of Mathematical Sciences Beijing Normal University Beijing 100875 China2. Department of Basic Courses Business College Beijing Union University Beijing 100025 China

We derive a quenched moderate deviations principle for the one-dimensional nearest random walk in random environment,where the environment is assumed to be stationary and *** approach is based on hitting time decompos... 详细信息

关键词： random walk in random environment moderate deviations principle hitting time

Sediment pollution and its effect on fish through food chain in the Yangtze River

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International Journal of Sediment Research 2008年第4期23卷 338-347页

Suspended sediment adsorbs pollutants from flowing water in rivers and deposits onto the bed. However, the pollutants accumulated in the river bed sediment may affect the bio-community through food chain for a long period of time. To study the problem the concentration of heavy metals (Cr, Cd, Hg, Cu, Fe, Zn, Pb and As) in water, sediment, and fish/invertebrate were investigated in the middle and lower reaches of the Yangtze River during 2.06-2.07. The concentrations of heavy metals were 100-10,000 times higher in the sediment than in the water. Benthic invertebrates had relatively high concentrations of heavy metals in their tissues due to their proximity to contaminated sediments. Benthic invertivore fish had moderately high concentrations of heavy metals whereas phytoplanktivore fish, such as the silver carp, accumulated the lowest concentration of heavy metals. The concentrations of Cu, Zn, and Fe were higher than Hg, Pb, Cd, Cr, and As in the tissue samples. The concentration of heavy metals was lower in the river sediments than in the lake sediments. Conversely, the concentration of heavy metals was higher in river water than in lake water. While a pollution event into a water body is often transitory, the effects of the pollutants may be long-lived due to their tendency to be absorbed in the sediments and then released into the food chain. The heavy metals were concentrated in the following order: bottom material > demersal fish and benthic fauna > middle-lower layer fish > upper-middle layer fish > water.

关键词： Sediment pollution Heavy metal Fish Invertebrate Yangtze River

Assessment and utilization of soil water resources

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Journal of Geographical Sciences 2001年第1期11卷 87-91页

作者： WANG Hui-xiao, LIU Chang-ming, YANG Zhi-feng (State key laboratory of Water {2. Simulation, {2. normal university, {2. 100875, China) State key laboratory of Water {2. Simulation Beijing Normal University Beijing China

Based on the analyses of water interactions and water balance, this paper discusses the issues on the assessment and regulation of soil water resources, which lays the scientific basis for limited irrigation and water... 详细信息

关键词： soil water resources assessment water interactions water balance