Advanced Materials Research Vols. 356-360

Abstract: A typical sub-region of Baiyangdian Lake is selected as the practical study area, which is characterized by irregular geometry and complex bathymetry. The coupled lattice Boltzmann model for simulating shallow water flow and pollutant transport in two dimensions is set up and applied to it. The wind stress is regarded as the main driven force. The bed friction and the gravitional force relating to bed slops are involved. The simulation results well represent the flow field and the distribution of pollutant concentration under the predominant wind. This study demonstrates that the lattice Blotzmann method possesses the robust capacity to deal with complex boundaries and irregular topography.

Abstract: The polyethersulfone ultra-filtration membrane was prepared by phase inversion method using polyethersulfone(PES), polyethylene glycol 400(PEG400) and N，N- dimethylamide(DMAC) as materials, and was modified by adding a capsaicin monomer named MBHBA which possess antibacterial property. The effects of MBHBA content on the ultra-filtration membrane performance were discussed. The results showed that the addition of MBHBA monomer effectively increased the membrane flux. And the modified membrane had strong inhibitory activity against Escherichia coli.

Abstract: In recent years, continuous and steady development of livestock breeding in Jiangxi Province, while brings enormous economic benefits to society, also has brought great impaction on natural environment. This paper estimated the output of pollutants (CODcr、BOD5、NH3-N、TP 、TN) and average TP/TN load on unit area of farmland from livestock breeding in Jiangxi province and analyzed the distribution characteristics of pollutants during 2007--2009. During these three years, output of main pollutants (CODcr, BOD5, NH3-N, TP and TN) from livestock breeding in Jiangxi Province increased slightly; the high load regions of TP/TN were mainly distributed in the areas with high total and those with relatively smaller area of farmland although the output is lower. Researches indicated that the output of pollutants from livestock breeding in Jiangxi Province had exceeded the local farmland bearing capability. Relevant departments should readjust the agricultural production structure following the principles of unified planning and rational distribution in order to effectively control non-point pollution from livestock breeding.

Abstract: As hydropower project construction and ecological support systems become more interdependent, new disciplines are needed to assess this ecological effect. An ecological footprint model of the hydropower project is presented based on the emergy theory (Em-EF). Modifications have been made to the Em-EF model, in response to its perceived shortcomings. The emergy of additional capacity of reservoir should be included in the renewable natural resources account. Further, the same emergy density should be used to calculate the ecological capacity supplied account and the ecological footprint occupied account. The aim of this paper is to show a modified ecological footprint calculation for the hydropower project. A large-scale (Ⅱ) hydropower project is selected as an example for the application. To demonstrate the mechanics of this modified method, we compared our calculations with the conventional one. The same conclusion is drawn using both methods: the ecological deficit of the hydropower project will occur before the design equilibrium year. But, the needed time to offset the ecological deficit is different. The modified model gives an even rational result than the conventional one.

Abstract: Lake Dong located in Wuhan is the largest urban lake in China. It has lost ecosystem functions with the economic development in recent years. The Lake Dong Ecological Water Network Project will reestablish the hydraulic connection between the Yangtze River and Lake Dong by diverting water from the river. In order to make a scientific water diversion scheme, a hydrodynamic and water quality model was established. Orthogonal curvilinear coordinate in horizontal direction and sigma coordination transformation in vertical direction were used. The model was verified using the observed COD concentration and applied to simulate three scenes of water diversion. By comparing the average COD of some sub-lakes in different scenes, a tactics of water diversion was proposed so as to provide a scientific basis for the project.

Abstract: In order to investigate the change of internal structure of porous media caused by arsenic deposition, X-ray difference micro-tomography was used to characterize the distribution of arsenic aggregates within porous media by scanning a series of arsenic samples prepared in the laboratory and arsenic-rich fluvial sediments from the Río Loa in Chile. After image processing, background noise in the tomograms was reduced and arsenic information was enhanced. Then the processed images were used to generate 3D spatial distribution datasets of arsenic in the media. Tools like Avizo6 and Blob3D were used to reconstruct and visualize the 3D datasets. 3D visualization showed that arsenic accumulated in the pore space and grain surface; arsenic aggregates of different sizes had distinctly different morphologies, which small aggregates tended to be spherical while big aggregates were relatively flat. These results show that difference micro-tomography can be used to observe the pre- and post-deposition structure of porous media, without any destruction to the samples.

Abstract: Abstract. Based on the twenty years’ hydrologic data and water quality materials from the year 2005 to 2010, this article studies the water environment changes of reservoir type water source and the water quality protection countermeasures. Through the analysis, it founds that, with the increase of the rainfall, voluminous non-point source pollution was brought to water. The increase of rainfall runoff influences differently to the reservoir's major pollutants -TN and TP. The increase of the rainfall runoff has a dilute effect on TN; with the increase of the rainfall runoff, the TP threshold will increase.

Abstract: Distributed hydrological models have become the main tool to study the hydrology natural law and solve the hydrology practice question. However, the definition of model parameter values limits their application. Manual calibration is time consuming and often tedious, and the automatic calibration method could be an innovative way of improving the traditional model fitting procedure. PEST is designed for easy linkage with other models and has been applied to many distributed hydrological model. Therefore, the PEST model is selected in this paper to link with the WATLAC model and calibrate the parameters, and compare the calibration results with manual results. The results show that the difference of two group parameter values is obvious. The PEST model can easily drive the WATLAC model and gain the optimal parameter values efficiently. The WATLAC model produces an overall good fit, the Ens values, except in 2001, are more than 0.83 and with an average of 0.93. But the relative runoff depth errors are larger slightly than manual results. The simulated stream flow hydrographs with PEST demonstrated a closer agreement with the observed hydrographs, while, the model simulation using manual calibration method behaved not very well and there was a tendency for the model to enlarge the peak flows.

Abstract: Climate change is one of the major global issues commonly concerned by international communities. Taking the Three Gorges Reservoir which is the largest water conservancy project in China as the study area, this study attempts to evaluate the variability of hydro-climatic elements including precipitation, temperature, relative humidity and sunshine hours during past 49 years (1961-2009) based on observed meteorological data, and predict the evolution trends of precipitation, temperature, evapotranspiration and runoff in the future 30 years (2021-2050) under climate change based on a distributed hydrological model and climate model outputs. Specifically, the temporal variations and sudden changes of precipitation, temperature, relative humidity and sunshine hours during past 49 years in the Three Gorges Reservoir are analyzed combining moving-average and linear regression with Mann-Kendall method, and the precipitation and temperature data in the future 30 years are obtained from the average dataset of 20 global climate models using a statistical downscaling model, and the evapotranspiration and runoff data in the future are obtained based on the validated hydrological model. The results indicate that: 1) during 1961-2009, the precipitation slightly decreased and the estimated sudden change time was 1973, the temperature significantly increased and the estimated sudden change time was 1963, the relative humidity decreased but there was no sudden change time estimated, the sunshine hours significantly decreased and the estimated sudden change time was 1967; 2) in the future, comparing with the historical average, the temperature in the region will increase by 1.3°C and the evapotranspiration will increase by 2.8%, while the precipitation and runoff will decrease by 0.8% and 8.2% respectively. Although the precipitation will not change greatly, the reduction extent of runoff is larger than that of precipitation, bringing forward higher requirements for integrated water resources management in the Three Gorges Reservoir.

Abstract: There are lots of methods of evaluating the environmental quality of groundwater. Based on a comprehensive analysis of those common methods, this paper puts forward a method named fuzzy comprehensive evaluation method on water environmental quality based on entropy weight with consideration of toxicology of evaluation factors. Developed from the entropy-based fuzzy comprehensive evaluation method, this method takes into account the influences caused by the toxicology weight and over standard weight of evaluation factors on the calculation of entropy weight. Through some water samples, the evaluation result of this method is more reasonable, objective and comprehensive than the one which is concluded from the entropy-based fuzzy comprehensive evaluation method.