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为考察填料式厌氧折流板反应器(CABR)处理分散式生活污水抗短期有机负荷冲击的稳定性,从宏观运行性能、中间产物累积以及微观微生物活性3个层次来研究不同温度下短期有机负荷冲击对CABR运行性能影响。结果表明:宏观运行性能指标TCOD沿程变化曲线在28℃时受到有机负荷冲击仍呈现"L"型,容积负荷去除率也由基准条件下0.27kg/(m3.d)提高至0.73 kg/(m3.d),但随温度的下降,沿程曲线逐渐接近"/"型,容积负荷去除率的增加幅度也逐渐变小。中间产物积累指标中VFA/碱度比值小于0.11~0.14时,TCOD去除率可达80%以上;SMP/SCOD比值沿水流方向呈上升趋势表明CABR抗负荷冲击性能较佳。而微观微生物酶活性受基质浓度提高的促进效应和温度下降的抑制效应相互作用表现各异。总体而言,在高温(28℃)条件下,分散式生活污水的有机负荷冲击不会对CABR出水造成显著影响,但在中温(18℃)和低温(10℃)条件下,CABR抗有机负荷冲击的稳定性随温度的下降而下降。 相似文献
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Chunming Jiang Guirui Yu Huajun Fang Guangmin Cao Yingnian Li 《Atmospheric environment (Oxford, England : 1994)》2010,44(24):2920-2926
An increasing nitrogen deposition experiment (2 g N m?2 year?1) was initiated in an alpine meadow on the Qinghai-Tibetan Plateau in May 2007. The greenhouse gases (GHGs), including CO2, CH4 and N2O, was observed in the growing season (from May to September) of 2008 using static chamber and gas chromatography techniques. The CO2 emission and CH4 uptake rate showed a seasonal fluctuation, reaching the maximum in the middle of July. We found soil temperature and water-filled pore space (WFPS) were the dominant factors that controlled seasonal variation of CO2 and CH4 respectively and lacks of correlation between N2O fluxes and environmental variables. The temperature sensitivity (Q10) of CO2 emission and CH4 uptake were relatively higher (3.79 for CO2, 3.29 for CH4) than that of warmer region ecosystems, indicating the increase of temperature in the future will exert great impacts on CO2 emission and CH4 uptake in the alpine meadow. In the entire growing season, nitrogen deposition tended to increase N2O emission, to reduce CH4 uptake and to decrease CO2 emission, and the differences caused by nitrogen deposition were all not significant (p < 0.05). However, we still found significant difference (p < 0.05) between the control and nitrogen deposition treatment at some observation dates for CH4 rather than for CO2 and N2O, implying CH4 is most susceptible in response to increased nitrogen availability among the three greenhouse gases. In addition, we found short-term nitrogen deposition treatment had very limited impacts on net global warming potential (GWP) of the three GHGs together in term of CO2-equivalents. Overall, the research suggests that longer study periods are needed to verify the cumulative effects of increasing nitrogen deposition on GHG fluxes in the alpine meadow. 相似文献
76.
Modeling changes in paddy rice sown areas in Asia 总被引:1,自引:0,他引:1
Wenbin Wu Ryosuke Shibasaki Peng Yang Huajun Tang Kenji Sugimoto 《Sustainability Science》2010,5(1):29-38
Paddy rice fields in Asia account for over 90% of global total rice cultivation area, and the major rice-producing countries
of Asia account for over one-half of the world’s population. Monitoring and understanding the dynamic changes in paddy rice
agriculture in Asia are very important for agricultural sustainability, food and water security, and greenhouse gas emissions.
This paper presents a crop choice decision model that dynamically simulates future changes in sown areas of paddy rice in
Asia. This model was developed under the framework of Action-in-Context (AiC) with the aim of understanding land users’ decisions
on crop choices among a set of available alternatives using a crop utility function. Empirical validation for the model conducted
after model construction indicated the reliability of the model for addressing the complexity of current agricultural land-use
change and its capacity for investigating long-term scenarios in the future. Finally, the model was applied for future scenario
analysis over a time frame of 30 years with 5-year increments, beginning from the year 2005. The simulation results provided
insights into rates and trajectories of changes in Asian rice areas over the test period, with the resulting implications
for future agricultural sustainability in Asia. These outcomes can improve understanding of projected land-use changes and
explain their causes, locations and consequences, as well as providing support for land-use planning and policy making. 相似文献
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Yingbin He Youqi Chen Huajun Tang Yanmin Yao Peng Yang Zhongxin Chen 《Environmental monitoring and assessment》2011,175(1-4):563-571
Spatially explicit ecosystem services valuation and change is a newly developing area of research in the field of ecology. Using the Beijing region as a study area, the authors have developed a spatially explicit ecosystem services value index and implemented this to quantify and spatially differentiate ecosystem services value at 1-km grid resolution. A gravity model was developed to trace spatial change in the total ecosystem services value of the Beijing study area from a holistic point of view. Study results show that the total value of ecosystem services for the study area decreased by 19.75% during the period 1996?C2006 (3,226.2739 US$ × 106 in 1996, 2,589.0321 US$ × 106 in 2006). However, 27.63% of the total area of the Beijing study area increased in ecosystem services value. Spatial differences in ecosystem services values for both 1996 and 2006 are very clear. The center of gravity of total ecosystem services value for the study area moved 32.28 km northwestward over the 10 years due to intensive human intervention taking place in southeast Beijing. The authors suggest that policy-makers should pay greater attention to ecological protection under conditions of rapid socio-economic development and increase the area of green belt in the southeastern part of Beijing. 相似文献
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Baoling Mei Xunhua Zheng Baohua Xie Haibo Dong Zaixing Zhou Rui Wang Jia Deng Feng Cui Huajun Tong Jianguo Zhu 《Atmospheric environment (Oxford, England : 1994)》2009,43(17):2762-2769
We conducted multi-year observations of nitric oxide (NO) fluxes from typical vegetable fields in the Yangtze River delta, which is located in southeastern China. Flux measurements were performed manually twice per week at intervals of 2–3 days, in both fertilized and unfertilized fields, over an investigation period of 1448 days (September 2004–August 2008). In total, twelve vegetable-growing periods and a short fallow period were investigated. On average, the NO fluxes from the fertilized plots were 21 times higher than fluxes from the unfertilized plots (p < 0.001). Peak NO emissions usually occurred soon after the addition of nitrogenous fertilizer. Peak emissions took place during about 15% of the whole investigation time, but contributed to approximately 89% of the total NO release. The annual background NO emissions (from fields without nitrogen amendment) were observed at 0.290 ± 0.019 (standard deviation of 3 observations) kg N ha?1. The total amounts of NO emitted during the individual vegetable-growing periods correlated positively and exponentially with the products of seasonal mean soil temperatures and nitrogen addition rates (R2 = 0.87, p < 0.001). The mean direct NO emission factor (EFd, the loss rate of fertilizer nitrogen via NO emissions) for the four-year period was determined to be 0.51% ± 0.11% (standard error of 3 observations). The EFds of individual vegetable-growing seasons ranged from 0.05% to 1.24%, varying linearly and positively with the products of seasonal mean soil temperatures and nitrogen addition rates (R2 = 0.58, p < 0.01). The observed interaction of soil temperature and nitrogen addition on NO emission in seasonal totals and EFds occurred in soils with moisture contents ranging from 55% to 100% water-filled pore space (mean: 79%; standard deviation: 9%). The results of this study indicate that when other conditions remain relatively stable, the direct emission factor, a key parameter for compiling an inventory of NO emissions from vegetable fields, may vary with not only soil temperature but also nitrogen addition. 相似文献
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Meizhen Wang Junjie Xu Juehua Wang Shuo Wang Huajun Feng Jiali Shentu Dongsheng Shen 《Environmental science and pollution research international》2013,20(9):6201-6209
To develop a bacterial bioaugmentation system for fluorine-containing industrial wastewater treatment, optimal conditions for 4-fluoroaniline (4-FA) degradation and autoinducer release in Acinetobacter sp. TW were determined. Quorum sensing in biofilms of strain TW was also investigated. Different optimal conditions exist for 4-FA degradation and autoinducer release, particularly with regard to pH. Quorum sensing modulates extracellular polymeric substance (EPS) secretion and biofilm formation in the strain but plays no role in 4-FA degradation. Under optimal conditions for 4-FA degradation, the release of N-3-oxo-hexanoyl-homoserine lactone (3-oxo-C6-HSL) and N-hexanoyl-homoserine lactone (C6-HSL) in strain TW was significantly lower than required for quorum sensing. Under optimal conditions for autoinducer release, on the other hand, 3-oxo-C6-HSL and C6-HSL levels exceeded the quorum sensing thresholds, thereby inducing EPS secretion and biofilm formation. We conclude that the optimal conditions for autoinducer release (25 °C, pH 5, 800 mg L?1 4-FA, and 0 % NaCl) are suitable for bacterial colonization in bioaugmentation, while those for 4-FA degradation (25–30 °C, pH 8 and 800 mg L?1 4-FA) maximize the system performance after colonization. 相似文献
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