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91.
以制药废水实验了50m3螺旋式厌氧反应器(SPAC反应器)的稳定性。采用AugmentedDickey—Fuller(ADF)单位根检验表明,螺旋式反应器具有良好的启动和运行稳定性。负荷冲击实验显示,SPAC反应器具有较好的耐浓度冲击能力和耐水力冲击能力,所能耐受的最大浓度冲击强度大于60000(mg·h)/L(进水浓度提升2倍),所能耐受的最大水力冲击强度为300(m3·h)/d(进水流量提升50%)。SPAC反应器还具备受扰恢复能力。在反应液pH低于5.74,出水浓度、COD去除率和容积COD去除速率(VRR)分别为3500mg/L、22.30%和2.52kg/(m3·d)的工况下,经过30d恢复,出水浓度、COD去除率和VRR的恢复程度达到80%~90%。  相似文献   
92.
杨珏  阮晓红 《生态环境》2001,10(3):256-258
农业非点源磷的输出是造成地表水富营养化的主要因素之一,弄清土壤磷的流失机理可为进一步控制农田径流磷的流失提供理论依据.文章总结了国内外在土壤磷素循环研究成果,并对其加以评述,在此基础上分析了土壤磷素循环对研究土壤磷的径流流失的重要作用.关健词土壤磷;循环;流失  相似文献   
93.
活性炭对含铅废水吸附特性研究   总被引:11,自引:6,他引:5  
采用静态法用活性炭吸附处理含铅废水,考察了活性炭对含铅废水的吸附特性。结果表明:活性炭对铅离子吸附平衡时间为100 m in;吸附等温方程为:Ce/qe=0.4298+0.0594Ce(25℃),该方程符合Langmu ir型吸附模式,不同温度下吸附平衡参数0RL1,表示该吸附为有利吸附。实验数据应用数学模型拟合,二级相关系数R2=0.9998,显示吸附过程动力学与二级动力学模型相关性较好;计算不同温度下各热力学参数:△Hθ大于零、△Gθ小于零,证实该吸附过程是一个自发吸热过程。△Sθ大于零,表明铅离子在固液界面有序性减小、混乱度增大。△Hθ值很小,说明该过程为物理吸附。  相似文献   
94.
本研究采用ZnCl2作为活化剂,用640W功率的微波照射5min的方法制备改性小麦秸秆。研究了改性小麦秸秆投加量、吸附时间、温度、pH对改性小麦秸秆吸附水溶液中Cu2+的影响,以及对其等温吸附特征、动力学和热力学进行了研究。试验结果表明:投加量为0.1g,pH为6,改性小麦秸秆对Cu2+有较好的吸附效果,吸附在10h后达到平衡。改性小麦秸秆对Cu2+吸附较好地符合Langmuir、Freundlich温吸附模型和准二级动力学方程,吸附过程中△G0,说明属于自发反应。  相似文献   
95.
BACKGROUND, AIMS AND SCOPE: Hexavalent chromium [Cr(VI)] cannot react with either carbonate or hydroxide to form chromium precipitates. However, by using a precipitation technology to treat plating wastewater containing Cr(VI), Cu(II), Ni(II) and Zn(II), approximately 78% of Cr(VI) (initial 60 mg/L) was co-removed with the precipitation of Cu(II), Ni(II) and Zn(II) (each 150 mg/L) by dosing with Na2CO3 (Sun 2003). Direct precipitation by forming Cu(II)-Cr(VI) precipitates followed by adsorption of Cr(VI) onto freshly formed Cu-precipitates was subsequently found to be the main mechanism(s) involved in Cr(VI) co-removal with Cu(II) precipitation by dosing Na2CO3 stepwise to various pH values (Sun et al. 2003). This study was. carried out to further characterize the formation of primary precipitates during the early stages of copper precipitation and simultaneous removal of Cr(VI) with Cu(II). METHODS: Test metal-solutions were prepared with industrial grade chemicals: CuCl2 x 2H2O, Na2SO4 and K2Cr2207. NaCO3 was added drop-wise to synthetic metal-solution to progressively increase pH. For each pH increment, removal of soluble metals was detected by atomic absorption spectrophotometer (AAS) and surface morphology of precipitates was analyzed by scanning electron microscope (SEM). To further characterize the formation of primary precipitates, a series of MINEQL+ thermodynamic calculations/analyses and equilibrium calculations/ analyses were conducted. RESULTS AND DISCUSSION: MINEQL+ thermodynamic calculation indicated that, for a system containing 150 mg/L Cu(II) and 60 mg/L Cr(VI) with gradual Na2CO3 dosing, if any precipitates can be formed at pH 5.0 or lower, it should be in the form of CuCrO4. Comparison tests using systems containing the same equivalent of Cu(II) plus Cr(VI) and Cu(II) plus SO4(2-) showed that the precipitation occurred at a pH of around 5.0 in the Cu(II)-Cr(VI) system and around 6.0 in the Cu(II)-SO4(2-) system. The discrepancy of the precipitation was indeed caused by the formation of Cu-Cr precipitates. The initiation of copper removal at pH around 5.0 for the Cu-Cr co-removal test was not attributable to the formation of Cu-CO3 precipitates, instead, it was most likely through the formation of insoluble Cu-Cr precipitates, such as CuCrO4 and CuCrO4 x 2Cu(OH)2. Experimental tests, equilibrium calculations, MINEQL+ thermodynamic calculations and surface morphologies for systems using higher concentrations of Cu(II) and Cr(VI) further verified the most probable composition of primary precipitates is copper-chromate. CONCLUSION: In the Cu-Cr co-removal test with Na2O3 dosing to increase pH and induce metal precipitation, copper-chromate precipitates are the primary precipitates produced and contribute to the initial simultaneous removal of copper and chromium.  相似文献   
96.
1998年长江大洪水与大气环流和海温异常分析   总被引:7,自引:2,他引:5  
概述了引起1998年长江大洪水的雨情,从天气气候角度分析了1998年长江流域降水异常偏多的原因。指出了最直接的原因是副高移动的反常,特别7月15日以后副高突然南撤南海季风爆发晚,南亚和东亚季风强度偏弱、夏季赤道辐合带偏弱热带地区台风生成少、生成时间晚,  相似文献   
97.
常温下IC反应器启动过程中的颗粒污泥性能研究   总被引:6,自引:1,他引:5  
在常温下用自配葡萄糖废水启动IC反应器,研究了厌氧颗粒污泥的形成过程和特性。IC反应器进水浓度为3 000 mg COD/L,水温为14.5~26℃,25 d内形成了颗粒污泥。结果表明,随着运行时间和容积负荷的增加,颗粒污泥粒径逐渐增大。反应器启动完成后,反应器中2 mm的颗粒污泥增加到6.6%,0.3 mm的颗粒从57.7%减少到39.4%;VSS浓度从24.7 g/L上升到48.2 g/L;VSS/SS从34.4%增加到72.8%。颗粒污泥的沉降速度与颗粒粒径成正比,0.3~3 mm的颗粒污泥的沉降速度介于34.05~109.75 m/h之间,具有良好的沉降性能。初始接种污泥几乎没有产甲烷活性,与第30 d的初期颗粒污泥相比,成熟的颗粒污泥的产甲烷活性提高了46.7%。  相似文献   
98.
ABSTRACT: Artificial circulation was applied at East Sidney Lake, a small, eutrophic impoundment in New York, to improve the water quality of the reservoir and tailwater. Treatment was successful at both reducing the stability of the reservoir and maintaining higher mean oxygen concentrations in the bottom waters. Discharge waters had lower metals and phosphorus concentrations during treatment years. However, vertical temperature differences, although minimal, were still sufficient to permit chemical stratification and some phosphorus release from the sediments. Frequent mixing events during periods of low stability, and runoff from storm events, also appeared to increase transport of phosphorus into the epilimnion. Overall, treatment did not result in decreases in algal populations or improvements in water clarity.  相似文献   
99.
全球能源消费与CO2排放量   总被引:13,自引:0,他引:13  
在收集全球能源储量和流通状况的基础上,综述了世界各地区能源消费量和各国人均能源水平,汇总了全球CO2排放总量及各大洲对全球CO2排放量的贡献率,到2100年,全球C矿量预计将从目前60亿t/a增加到360亿t/a,同时,旨出1996年中世界人口18.8%的北美、欧洲、日本、CO2排放31.6亿t(碳),占全球当年CO2排放总量的52.4%。  相似文献   
100.
The present study investigates the influences of synoptic-scale air flows and local wind circulations on the dust layer height (DLH) in the Taklimakan Desert, based on lidar observations performed in the north of the desert in March 2003. The DLH fluctuates approximately every three days between 2500 m (above sea level) and 5000 m, including diurnal variations. Meteorological analyses and numerical simulations show that the three-day fluctuation of DLH corresponds with variations in synoptic-scale air flows over the Taklimakan Desert, and the diurnal variations are linked to downdrafts and updrafts that are formed over the north of the desert as part of local circulations. When strong northerly winds prevail in the upper troposphere and a developed valley wind blows toward the Tienshan Mountains in the lower troposphere, the downdrafts strengthen in the middle troposphere over the north of the desert, lowering the DLH to about 2500 m. In contrast, the DLH rises to about 5000 m when the updrafts develop between strong southerly winds in the upper troposphere and a developed mountain wind blowing from the Tienshan Mountains. Simulations for the local circulation behavior without the presence of the Tienshan Mountains demonstrate that the valley and mountain winds on the southern slope of the Tienshan Mountains control the intensity of the downdrafts and updrafts, thereby influencing the DLH over the north of the Taklimakan Desert.  相似文献   
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