Xiayun Township watershed in the upper reaches of Hongfeng Lake is selected to study the relationship between stream grade and water quality.Turbidity and ammonium nitrogen concentration are obviously related to the s...Xiayun Township watershed in the upper reaches of Hongfeng Lake is selected to study the relationship between stream grade and water quality.Turbidity and ammonium nitrogen concentration are obviously related to the stream grade,generally speaking,are positively correlated,and the water quality is degrading from the upper reaches to the lower reaches.In the future,the influence of different land use types on the water quality should be fully analyzed on the basis of enhancing the water quality monitoring to provide supports for effectively controlling non-point source pollutions and treating the water environment of Hongfeng Lake.展开更多
Water quality is critical to ensure that marine resources and the environment are utilized in a sustainable manner. The objective of this study is therefore to investigate the optimum placement of marine environmental...Water quality is critical to ensure that marine resources and the environment are utilized in a sustainable manner. The objective of this study is therefore to investigate the optimum placement of marine environmental monitoring sites to monitor water quality in Shanghai, China. To improve the mapping or estimation accuracy of the areas with different water quality grades, the monitoring sites were fixed in transition bands between areas of different grades rather than in other positions. Following bidirectional optimization method, first, 18 candidate sites were selected by filtering out specific site categories. Second, three of these were, in turn, eliminated because of the rule defined by the changes in the areas of water quality grades and by the standard deviation of the interpolation errors of dissolved inorganic nitrogen(DIN) and phosphate(PO_4-P). Furthermore, indicator kriging was employed to depict the transition bands between different water quality grades whenever new sampling sites were added. The four optimization projects of the newly added sites reveal that, all optimized sites were distributed in the transition bands of different water grades, and at the same time in the areas where the historical sites were sparsely distributed. New sites were also found in the overlap region of different transition bands. Additional sites were especially required in these regions to discriminate the boundaries of different water quality grades. Using the bidirectional optimization method of the monitoring sites, the boundaries of different water quality grades could be determined with a higher precision. As a result, the interpolation errors of DIN and PO_4-P could theoretically decrease.展开更多
Pretreatment of high content of Si- and Al-containing cyanide tailings by water leaching to remove some impurities, such as the major impurities minerals of Si and A1, as well as its effect on Fe extraction in the wat...Pretreatment of high content of Si- and Al-containing cyanide tailings by water leaching to remove some impurities, such as the major impurities minerals of Si and A1, as well as its effect on Fe extraction in the water leaching process was investigated. The effects of different parameters on iron recovery were studied, and the reaction parameters were proposed as follows： sodium carbonate content of 30%, water leaching at 60 ~C for 5 min, liquid/solid ratio of 15：1, and exciting current of 2 A. Under these optimal conditions, magnetic concentrate containing 59.11% total iron and a total iron recovery rate of 76.12% was obtained. In addition, the microstructure and phase transformation of the process of water leaching were studied by X-ray powder diffraction technique （XRD）, Electronic image of backscattering （BEI）, X-ray fluorescence （XRF）, and energy dispersive spectrometry （EDS）. The results indicate that the soluble compound impurities generated in the roasting process are washed out, and the dissoluble substances enter into nonmagnetic materials by water leaching, realizing the effective separation of impurities and Fe.展开更多
文摘Xiayun Township watershed in the upper reaches of Hongfeng Lake is selected to study the relationship between stream grade and water quality.Turbidity and ammonium nitrogen concentration are obviously related to the stream grade,generally speaking,are positively correlated,and the water quality is degrading from the upper reaches to the lower reaches.In the future,the influence of different land use types on the water quality should be fully analyzed on the basis of enhancing the water quality monitoring to provide supports for effectively controlling non-point source pollutions and treating the water environment of Hongfeng Lake.
基金supported by the National Natural Science Foundation of China(Nos.41376190,41531179,41421001 and 41601425)the Scientific Research Project of Shanghai Marine Bureau(No.Hu Hai Ke2016-05)the Ocean Public Welfare Scientific Research Project,State Oceanic Administration of the People’s Republic of China(Nos.201505008 and 201305027)
文摘Water quality is critical to ensure that marine resources and the environment are utilized in a sustainable manner. The objective of this study is therefore to investigate the optimum placement of marine environmental monitoring sites to monitor water quality in Shanghai, China. To improve the mapping or estimation accuracy of the areas with different water quality grades, the monitoring sites were fixed in transition bands between areas of different grades rather than in other positions. Following bidirectional optimization method, first, 18 candidate sites were selected by filtering out specific site categories. Second, three of these were, in turn, eliminated because of the rule defined by the changes in the areas of water quality grades and by the standard deviation of the interpolation errors of dissolved inorganic nitrogen(DIN) and phosphate(PO_4-P). Furthermore, indicator kriging was employed to depict the transition bands between different water quality grades whenever new sampling sites were added. The four optimization projects of the newly added sites reveal that, all optimized sites were distributed in the transition bands of different water grades, and at the same time in the areas where the historical sites were sparsely distributed. New sites were also found in the overlap region of different transition bands. Additional sites were especially required in these regions to discriminate the boundaries of different water quality grades. Using the bidirectional optimization method of the monitoring sites, the boundaries of different water quality grades could be determined with a higher precision. As a result, the interpolation errors of DIN and PO_4-P could theoretically decrease.
基金Projects(ZR2010EL006,Y2007F60) supported by the National Science Foundation of Shandong Province of ChinaProject(J12LA04) supported by High Education Science Technology Program of Shandong Province,China
文摘Pretreatment of high content of Si- and Al-containing cyanide tailings by water leaching to remove some impurities, such as the major impurities minerals of Si and A1, as well as its effect on Fe extraction in the water leaching process was investigated. The effects of different parameters on iron recovery were studied, and the reaction parameters were proposed as follows： sodium carbonate content of 30%, water leaching at 60 ~C for 5 min, liquid/solid ratio of 15：1, and exciting current of 2 A. Under these optimal conditions, magnetic concentrate containing 59.11% total iron and a total iron recovery rate of 76.12% was obtained. In addition, the microstructure and phase transformation of the process of water leaching were studied by X-ray powder diffraction technique （XRD）, Electronic image of backscattering （BEI）, X-ray fluorescence （XRF）, and energy dispersive spectrometry （EDS）. The results indicate that the soluble compound impurities generated in the roasting process are washed out, and the dissoluble substances enter into nonmagnetic materials by water leaching, realizing the effective separation of impurities and Fe.
