Advanced Materials Research Vols. 347-353

Abstract: Rainfall interception is an important hydrological process occurred in soil-plant-atmosphere continunm(SPAC). Understanding the hydrological response in vegetation will help us improve water use efficiency. In this paper, an investigation of leaf water absorption and desorption was conducted through two land cover plants of white clover (Trifolium repens L.) and milk vetch (Astragalus adsurgens Pall.) under simulating rainfall conditions. The purpose was to evaluate the capacity of water retention in the leaf level. The results showed that the leaf water absorption of the two plants was rapid at the initial stage of rainfall interception, tended to be slowness after one hour, and finally got a threshold, which is turgid leaf water content. While the intercepted water by leaf faded away, the leaf started to get desorption. The processes of leaf water desorption of the two plants were similar to the process of leaf water absorption. The rate of desorption was rapidly at the initial stage after water on the leaf surface faded away, then tended to be slow down while a time, and finally got a threshold of leaf water content. Relative to the process of water absorption, the process of water desorption lasted longer time. The models of both water absorption and desorption can be expressed as: C=C0(1-e-kt). The results also showed that turgid leaf water content rose linearly with the increase of SLA.

Abstract: Prompted by the constructed wetland without long-term stable operation and anaerobic baffled reactor (ABR) with higher suspended solid (SS) removal rate, an anaerobic stage-constructed wetland integrated sewage treatment system was designed and applied to treat low-concentration domestic sewage from campus. The hydraulic retention times (HRTs) of anaerobic stage and constructed wetland were set as HRT1, HRT2 by our research. All the trials lasted 30 months, and the results of trial indicated that SS removal rate of the ABR stage was at least 82% under the condition that HRT1 ≥20h. At（ 22±2）°C, under the conditions that HRT1=45h and HRT2=15h, the COD, TN, TP removal rates of integrated wastewater treatment system could be over 82.38%, 76.75% and 71.29%, respectively. Based on the results of trial, the operational life of constructed wetland integrated with ABR was evaluated that at least 4 times than that of individual constructed wetland, and the mechanisms of higher efficacy and long-term stable operation of integrative sewage treatment system in treatment of low-concentration domestic sewage from campus were owed to high efficient SS removal rate at ABR stage.

Abstract: This paper reports on the method of linking climate change scenarios with hydrologic and agricultural theory to study agriculture water demand under changing climate conditions, which is applied in Shiyang River basin, in Northwest China. We calculate agriculture water demand by use of Penman-Monteith formula and field water balance theory, droved by climate factors. This paper concludes that, the response of agriculture water demand to climate change exists, but the climate change can’t vary the basic law of water resources system; reference evapotranspiration (ET0) and temperature represent positive correlation, moreover, agriculture water demand and temperature also exist positive correlation, however, agriculture water demand and precipitation show the evident negative correlation; the influence of agriculture water demand which induced by temperature increase or decrease 1°C is larger than that induced by precipitation increasing or decreasing 10%; the influence range of agriculture water demand which induced by precipitation decrease is larger than that induced by precipitation increase; the influence range of agriculture water demand which induced in the guarantee rate of 75% is larger than that which induced in the guarantee rate of 50%; in additionally, the influence range of agriculture water demand in 2020 is larger than that in 2010. Therefore, in these relatively water shortage areas, changes in agriculture water demand due to climate change will require timely improvement in crop cultivars, irrigation and drainage technology, and water management.

Abstract: A generalized approach for the economic selection of wind turbine for a given wind regime is proposed in this paper. It draws from the literature and standards being used in the field to arrive at an economic site specific wind turbine based on minimizing the annual cost of energy produced (AEP) while tracking the initial capital cost (ICC) of investment required. It is meant to provide an initial study to guide decision makers who are contemplating using wind energy as a power source to generate electricity in commercial quantity for community usage. It is a general estimation approach which does not require surfing for manufacture prices and wind turbine parameters. The input data consists of site specific wind data, hub height, rotor diameter and turbine power rating. The output gives a range of plots of feasible wind turbine ratings, rotor diameters, rated speed against initial capital cost (ICC) and also cost of energy produced (COE).

Abstract: The residual levels and dissipation rates of metaldehyde in cabbage and soil at three main cabbage-growing areas in china were determined by A simple，rapid and sensitive analytical method with liquid chromatography with TripleQuad mass spectrometry (LC–MS–MS). The limit of quantification (LOQ) was 0.0005,0.0005mg/kg for soil and cabbage, respectively. The mean half-life of metaldehyde was 5.84 days in cabbage and 3.17 days in soil. The final residues in cabbage and soil detected at 7 days after the last spreading were considerably all below 1mg/kg (the MRL of China). Low residues in cabbage and soil suggest that this pesticide may be safe to use under the recommended dosage.

Abstract: Taking the day numbers of daily average temperature ≥30°C and the day numbers of daily maximum temperature ≥35°C as the index of high temperature disaster, the occurrence regularity of high temperature disaster for June to September was analyzed from 1961 to 2010 in Chongqing. The results showed that there was a large inter-decadal variation in occurrence of high temperature disaster. The most severe year of high temperature disaster was the year of 2006, while the year of 1987 is the lightest one. The general trend was that it was the lowest one in the 1980s and gradually increased in the 1990s, and reached the highest value in the 2000s. The spatial distribution of the day numbers of daily average temperature ≥30°C was the same as that of the day numbers of daily maximum temperature ≥35°C. The highest values were distributed at the areas of Kaixian, Yunyang, Wushan in the Northeast part and Fengdu, Fuling in the middle part and Banan,Shapingba,Beibei in urban district and Qijiang in the southwest part. The lowest values were distributed at the areas of Xiushan,Youyang,Qianjiang in the southeast part and Chengkou,Fengjie in the northeast part and Dazu,Rongchang in the west part.

Abstract: The result showed that, after addition of a suitable content zeolite to A/O tank, the zeolite sludge had a low resistance and a high membrane flux. The heavy metals in municipal wastewater were inactivated and types of organic matter were adsorbed by the sludge containing zeolite, while sludge compressibility was decreased. It also changed the chemical composition of the sludge and added the inorganic substances such as silicon, aluminum, potassium and sodium, which obviously influenced the way the sludge could be reused.

Abstract: In this paper, ultrasonic pretreatment was used to improve the aerobic/anoxic digestion of sewage sludge. The extracellular polymeric substances (EPS) and enzymes in the digestion were analysed to understand the mechanisms responsible for this improvement. The results showed that the ultrasonic pretreatment enhanced enzymatic activities and accelerated the solubilisation of the EPS. In addition, ultrasonic pretreatment could not only break flocs and release extracellular materials but also destroy cells and release intercellular materials. With ultrasonic pretreatment, the sludge reduction for volatile suspend solids (VSS) in aerobic/anoxic digestion was 41.97±0.66%, compared with 22.81±1.40% for the control treatment, after an aerobic/anoxic digestion time of 10 d. Fourier transform infrared (FT-IR) spectroscopy results showed that the polymeric compounds, proteins and polysaccharides were easily hydrolysed and biodegraded in ultrasonic-treated sludge.

Abstract: With the continuing phenomenon of eutrophication, the pollution of nitrogen has caused wide concern. Lack of organic carbon sources is always considered to be a key problem for nitrogen removal efficiency and cost when conventional biological nitrogen removal process was used to the treatment of ammonium-rich wastewater, but the anaerobic ammonium oxidation（ANAMMOX）can solve this problem .Anammox has so many advantages that it has good prospects in the biological nitrogen removal in wastewater. Anammox bacteria grows slowly, has a long generation time, and is susceptible to the environmental conditions. DO, Temperature, pH and organic can impact the process of anammox, so it is necessary to take careful methods to cultivate Anammox biomass. Depending on the purpose of improve water quality, appropriate treatment reactors and seed sludge should be selected to start ANAMMON process. The discovery of anaerobic ammonia oxidation, the reaction mechanism, influence application, the enrichment of anammox bacteria, physiological and biochemical characteristics of anammox bacteria, the start of anaerobic ammonia oxidation are reviewed in this paper.

Abstract: Samples of water were collected from the subsidence pools around the coal waste rock piles and some toxic trace elements were determined. The results conclused as the mean concentrations of As, Zn and Pb ranged from 4.71E-03 to 1.78E-02, 9.22E-03 to 2.13E-02, 1.69E-03 to 5.43E-03, respectively, which were lower than the first level of surface water environment quality standards established in China. The mean concentrations of Cd and Cu ranged from 3.30E-04 to 1.25E-03, 1.04E-02 to1.85E-02, respectively, which were within the range of the second level. As the HQs of As, Zn, Pb, Cd, Cu were less than 1, suggesting minimal noncarcinogenic risk to human health. Only As was evaluated with potential carcinogenic risks of 3.17E-04 and 2.02E-04 (>10-4) in the water of subsidence pools around Panyi and Guqiao coal waste rock piles via oral consumption, indicating that As had potential adverse effects on local residents in these two sites. This study is to investigate the contamination levels of trace elements and to estimate the risk to health effects in the water of the subsidence pools in Huainan.