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Cheng S.,Changan University | Li Y.,Shaanxi Provincial Academy of Environmental Science
Applied Mechanics and Materials | Year: 2013

Too much worry on the safety of nuclear power has made many people take a negative attitude to the development of nuclear power. Nuclear safety experts pointed out that the nuclear fear of people is often due to little knowledge on the nuclear power. The paper analyses comprehensively the advantages of nuclear power, the safety of nuclear power, the reasons of nuclear power accident and its implications. Basised on these, development prospects of nuclear power is discussed. © (2013) Trans Tech Publications, Switzerland.

Hou Y.-P.,China University of Technology | Peng D.-C.,China University of Technology | Wang B.-B.,China University of Technology | Zhang X.-Y.,China University of Technology | Xue X.-D.,Shaanxi Provincial Academy of Environmental Science
Desalination and Water Treatment | Year: 2014

Abstract: The anaerobic sludge granulation was studied in two laboratory-scale continuous-flow stirred tank reactors (CSTRs), which treating synthetic glucose wastewaters under a mesophilic constant temperature of 35 ± 1°C. Different stirring strategies were employed in the two CSTRs. Magnetic stirring at a rotation speed of 140 rpm was used in CSTR1 and axial continuous agitation at a speed of 90 rpm in CSTR2. It was observed that highly activated granular sludge formed in CSTR2, but flocculent sludge still remained in CSTR1 after about 45 days’ cultivation. Liquid circulation analysis of the two stirring modes displayed that the overall circulation in CSTR2 was more uniform. Furthermore, calculation results proved that the hydraulic shear force produced in CSTR2 was more suitable for granules formation than it in CSTR1, and granules did form in the CSTR2. Therefore, it could be concluded that in the laboratory-scale CSTR, stirring strategy played a key role in sludge granulation. On the other hand, scanning electron microscope images of granular sludge displayed that filamentous bacterial dominated in the outer layer and bacilli surrounded by lots of extracellular polymeric substances in the inner layer. Both of these are beneficial to promote the granules formation and maintenance. © 2013, © 2013 Balaban Desalination Publications. All rights reserved.

Zhao Y.,Southwest University | Gao M.,Shaanxi Provincial Academy of Environmental Science | Chen X.,Southwest University | Mo B.,Southwest University
Energy Education Science and Technology Part A: Energy Science and Research | Year: 2013

The Erosion-productivity impact calculator (EPIC) model was used to estimate soil erodibility (K) in a small watershed where the main soil type is purple soil. Purple soil is a typical sandy loam soil in the Three Gorges reservoir area and most distributes in southwest China. The objectives of this paper were to explain the relationship between erodibility (K) and land-uses. Spatial variability characteristics of soil erodibility (K) under different land-uses (woodland - Pinus massoniana Lamb and Robinia pseudoacacia L, economic fruit forest - Citrus reticulata Banco, cropland - Zea mays L and Lpomoea batatas, wastegrassland) were studied. Results indicated that: (1) Soil texture and human activities were the main factors that influenced the soil erodibility (K), erodibility (K) increased with the content of sand while decreased with the content of silt, clay and organic matter. (2) The order of soil erodibility (K) from large to small under six land-uses in the watershed was: waste-grassland > economic fruit forest (Citrus reticulata Banco)> woodland (Pinus massoniana Lamb)> woodland (Robinia pseudoacacia L) > cropland (Lpomoea batatas) > cropland (Zea mays L). (3) Soil erodibility (K) of the whole purple soil watershed area showed a positive trend with elevation of the watershed from east to west. Erodibility (K) of woodland (Robinia pseudoacacia L) exhibited Kupstream < Kmidstream < Kdownstream, however, the erodibility (K) under other land-use showed the opposite trend, manifesting in Kupstream > Kmidstream > Kdownstream. © Sila Science.

Zhang X.,Key Laboratory of Northwest Water Resources and Environment Ecology of MOE at XAUT | Zhang X.,Shaanxi Provincial Academy of Environmental Science | Yu G.Q.,Key Laboratory for Geo hazards in Loess Area of Ministry of Land and Resources | Li Z.B.,Key Laboratory of Northwest Water Resources and Environment Ecology of MOE at XAUT | And 2 more authors.
Water Resources Management | Year: 2014

The relationships between precipitation, vegetation and erosion are important yet unresolved issues in the field of earth surface processes. Vegetation plays an important role in controlling soil erosion. Through field simulated rainfall experiments, we analyzed the characteristics, regulation of, and correlation among the slope rainfall-infiltration-runoff, erosion and sediment under different vegetation types. The results showed that the forest effectively improved soil structure, had stronger runoff and sediment regulation and was influenced less by rainfall intensity than those under other vegetative conditions. In addition, the efficiency and pattern of the regulation of runoff and sediment varied with vegetation types as did the mechanism of action. The soil and water conservation function of forest was water storage and sediment reduction by plant root systems to reduce erosion power, increase infiltration, decrease runoff and reduce flow speed. The function of grassland was direct sediment interception based on surface vegetation canopy for runoff and sediment regulation. The root contribution to runoff and sediment reduction was relatively greater than the shoot contribution under forest conditions, whereas, the effect of shoots and roots on soil loss was almost equivalent under grassland conditions. The different spatial structures of vegetation affected runoff and sediment regulation in different ways, and plant root systems were crucial for soil and water conservation. The cumulative sediment yield of the slopes increased as a statistically significant power function of cumulative runoff. The coefficient and curve shape of function were dependent on vegetation type, soil properties, rainfall intensity and surface roughness. The process of slope runoff and sediment was divided into development, active and stable stages. These stages correlated with each other to constitute a complete rainfall-runoff and erosion-sediment process, which exhibited their own features at each stage. This study furthers understanding of the relationships between vegetation, soil erosion and precipitation. © 2014 Springer Science+Business Media Dordrecht.

Hou Y.-P.,Xian University of Architecture and Technology | Peng D.-C.,Xian University of Architecture and Technology | Xue X.-D.,Shaanxi Provincial Academy of Environmental Science | Wang H.-Y.,Xian University of Architecture and Technology | Pei L.-Y.,Xian University of Architecture and Technology
Journal of Bioscience and Bioengineering | Year: 2014

Hydrogenotrophic methanogens had been considered as key species for the anaerobic digestion (AD) of industrial wastewater and municipal sludge. However, how to evaluate the activity of the hydrogenotrophic methanogens was less studied. In this study, a volumetric device and a test procedure were developed for measuring the specific hydrogen utilization rate (HUR) of anaerobic sludge. Results showed that HUR values were highly influenced by sludge concentrations because of limitation on H2 mass transfer. The critical value of sludge concentration in the test bottle should not be higher than 1 gVSS/L. Under such condition, the kinetics of HUR would not be limited by H2 mass transfer and the maximal value of HUR could be obtained. Field survey confirmed that HUR exhibits a good relationship with specific methanogenic activity (SMA) and reactor performance. An anaerobic system with a relatively high HUR was found to be beneficial for maintaining H2 partial pressure in an appropriately low level. Moreover, such system was thermodynamically favourable for the syntrophic degradation of volatile fatty acids. As a crucial parameter of the anaerobic process, HUR could be used as a key indicator for evaluating and monitoring AD processes. © 2013 The Society for Biotechnology, Japan.

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