蓄热式热氧化器的改进与应用

为了解决城市周边小企业挥发性有机物空气污染问题,研发了一种新型多蓄热室旋转换向蓄热式热氧化器,对现有蓄热式热氧化器内不合理的流通截面积分配比例进行了改进,并在北京市郊某工厂建设了处理能力3 000 m3/h的应用示范装置.应用情况表明,新型蓄热式热氧化器对VOC的处理效率可达96%,同时比常规热力焚烧炉节能70%以上....     

用于地表水反硝化的纤维素碳源选择研究

为了选取合适的天然有机物作为反硝化细菌碳源用于解决地表水中NO3--N污染问题,以江南大学校内湖水为接种物,选取8种天然纤维素碳源在缺氧状态不同的处理方式下对60 mg/L NO3--N的降解特性进行研究。结果表明,以碱处理作为预处理可明显提高反硝化速率,碳源脱氮率均在96%以上（树皮除外）。2种处理方式中均有NO2--N累积,部分碳源释放NH4＋-N并发生DNRA反应,树叶在2种处理中脱氮效果均较好。结合各碳源脱氮率、耗碳源量以及处理成本,选取基本处理的香樟叶作为最佳纤维素碳源。     

An International Comparative Analysis on China's Economic Growth and the Convergence in Energy Intensity Gap and Its Economic Mechanism

In this paper,the authors have empirically analyzed the convergence in per capita GDP gap and the convergence in the variation of energy intensity with respect to the change of per capita GDP between China and eight developed countries.Then,the authors run a regression on the impact of decisive factors of economic growth on energy intensity and its change,so as to find out the economic mechanism of energy intensity gap changing with respect to the variation of economic growth.This study concludes that:First,there is a convergence in per capita GDP gap between China and the eight developed countries.With the convergence in per capita GDP gap,the energy intensity gap between China and eight different countries also converge,and the convergence rate of the latter is faster than that of the former,i.e.if the per capita GDP gap between China and the eight developed countries decreases by 1%,the energy intensity gap between them will correspondingly decrease by 1.552%.Second,the energy intensity decreases with the improvement of industrial structure,the rising of energy prices,the advances of technology,and the expansion of investment in fixed assets,and it slightly increases with the increase of FDI.Third,the energy intensity gap between China and eight developed countries narrows with the lessening of the difference in fixed assets investment,energy prices,and technological progress between China and eight developed countries,yet increases with the narrowing of the difference in FDI,and has no significant correlation with the difference in industrial structure.Fourth,the narrowing of difference in per capita GDP between China and the eight developed countries can result in the lessening of energy intensity gap,whose economic mechanism is that the decisive factors,such as difference in investment,technology,and the competition mechanism of prices,which can determine the difference in economic growth,can significantly affect the energy intensity gap.     

广东河源电厂循环水高浓缩倍率试验研究及工程应用

循环冷却系统浓缩排污水是电厂最大的排污水,是节水减排和废水零排放的关键问题之一。以河源电厂为例,分析了电厂进水水质条件;选用了5种水稳剂,采取极限碳酸盐硬度计算浓缩倍率的方法,通过静动态阻垢、防腐与杀菌试验,探明了各种药剂的极限浓缩倍率,论证了河源电厂循环冷却系统10倍以上的浓缩倍率运行方式的可行性。按试验所确定的原则,河源电厂循环冷却水系统按10倍的浓缩倍率运行,一年来未出现腐蚀与结垢现象。分析了实际运行期间的运行数据,对我国循环冷却水处理、节约用水、减少排污具有一定的示范意义。     

纤维素酶处理玉米秸秆对染料的吸附

采用纤维素酶处理玉米秸秆颗粒,考察了玉米秸秆颗粒粒径、纤维素酶溶液体积浓度和pH、酶解温度、酶解时间等条件对玉米秸秆颗粒吸附染料性能的影响.实验结果表明,当玉米秸秆颗粒粒径为0.55～0.83 mm、纤维素酶溶液加入量为0.9 mL/L、纤维素酶溶液pH为4.5±0.1、酶解温度为55℃、酶解时间为80 min时,经纤...     

我国各省市报废汽车量预测

根据统计数据,采用加权平均法计算我国汽车平均使用年限为12年;根据各省市1998—2008年汽车新增消费量统计数据,推测得到2010—2020年各省市汽车报废量;分析了报废汽车中载货车、客车和轿车结构特征和报废汽车东、中、西部区域分布特征。     

Determinations of hexabromocyclododecane (HBCD) isomers in channel catfish, crayfish, hen eggs and fish feeds from China by isotopic dilution LC-MS/MS

HBCD is widely used brominated flame retardant, which is increasingly reported in the environment. A new isotopic dilution LC-MS/MS method was developed to determine three HBCD isomers, α-, β- and γ-HBCD in channel catfish, crayfish, hen eggs and fish feeds in this study, and especially for the first time HBCD isomers composition in crayfish, hen eggs and fish feeds. Soxhlet extractor and GPC cleanup were used, some important steps and crucial parameters were modified and intensified compared with other literatures, and LC and MS/MS conditions were optimized. The limits of quantitation values of 0.01, 0.005 and 0.005 ng g⁻¹ wet weight in channel catfish and crayfish were calculated for three HBCD isomers, respectively; so did 0.1, 0.05 and 0.05 ng g⁻¹ wet weight in eggs and 0.2, 0.1, 0.1 ng g⁻¹ wet weight in fish feeds. Recoveries of α-HBCD, β-HBCD and γ-HBCD were ranged between 75% and 105% for these productions at medium and high-level spiked samples, and between 60% and 85% at low-level spiked samples. The established methods were therefore suitable for the determinations of three HBCD isomers in these productions at trace contamination levels. Moreover, thirty commercial channel catfish, crayfish, hen eggs and fish feeds samples collected from local markets, and thirty home-produced hen eggs from private owners in Hubei province of China, were analyzed to determine whether these productions were contaminated by HBCD. Using the established methods, HBCD emerged in 4 of 30 fish feeds and 3 of 30 home-produced eggs, and in low-ng g⁻¹ wet weight.     

Enhancement of chlorophenol sorption on soil by geophagous earthworms (Metaphire guillelmi)

Earthworms are the dominant soil biomass of many terrestrial ecosystems and markedly influence the physico-chemical and biological properties of soil; however, little is known about the effects of earthworm activities on the environmental behavior of micropollutants in soil. We studied the sorption and desorption of 2,4-dichlorophenol, 2,4,6-trichlorophenol, and pentachlorophenol on geophagous earthworm (anecic Metaphire guillelmi) casts of various aging times and on the parent soil. The casts were characteristic of lower pH and higher content of fine particles (silt and clay) than the parent soil. The sorption of the chlorophenols on the soil and casts were well fitted to linear isotherms, with sorption capacity in the order of pentachlorophenol > 2,4-dichlorophenol > 2,4,6-trichlorophenol. The sorption on the cast with different aging time was quite similar and was higher than on the parent soil. The sorption on the soil did not change between pH 7.07 of the soil and pH 6.76 of the casts. The desorption hysteresis of the chlorophenols on the soil and casts was compound specific and 2,4,6-trichlorophenol showed the highest hysteresis. The higher sorption capacity of the casts was not owing to the lowered pH of the casts, but mainly to the higher fine particles in the casts and the possible changes of nature of the soil organic matter through the earthworm gut passage. Our results indicate that geophagous earthworms may change sorption behavior and thus the bioavailability and transport of chlorophenols in soil. Earthworm effects should be considered when evaluating the environmental behavior and risk of organic pollutants in the ecosystems where earthworms are abundant.     

Quantifying the Effect of Ecological Restoration on Soil Erosion in China’s Loess Plateau Region: An Application of the MMF Approach

Land degradation due to erosion is one of the most serious environmental problems in China. To reduce land degradation, the government has taken a number of conservation and restoration measures, including the Sloping Land Conversion Program (SLCP), which was launched in 1999. A logical question is whether these measures have reduced soil erosion at the regional level. The objective of this article is to answer this question by assessing soil erosion dynamics in the Zuli River basin in the Loess Plateau of China from 1999 to 2006. The MMF (Morgan, Morgan and Finney) model was used to simulate changes in runoff and soil erosion over the period of time during which ecological restoration projects were implemented. Some model variables were derived from remotely sensed images to provide improved land surface representation. With an overall accuracy rate of 0.67, our simulations show that increased ground vegetation cover, especially in forestlands and grasslands, has reduced soil erosion by 38.8% on average from 1999 to 2006. During the same time period, however, the change in rainfall pattern has caused a 13.1% ± 4.3% increase in soil erosion, resulting in a net 25.7% ± 8.5% reduction in soil erosion. This suggests that China’s various ecological restoration efforts have been effective in reducing soil loss.     

Quantifying Terrestrial Ecosystem Carbon Dynamics in the Jinsha Watershed, Upper Yangtze, China from 1975 to 2000

Quantifying the spatial and temporal dynamics of carbon stocks in terrestrial ecosystems and carbon fluxes between the terrestrial biosphere and the atmosphere is critical to our understanding of regional patterns of carbon budgets. Here we use the General Ensemble biogeochemical Modeling System to simulate the terrestrial ecosystem carbon dynamics in the Jinsha watershed of China’s upper Yangtze basin from 1975 to 2000, based on unique combinations of spatial and temporal dynamics of major driving forces, such as climate, soil properties, nitrogen deposition, and land use and land cover changes. Our analysis demonstrates that the Jinsha watershed ecosystems acted as a carbon sink during the period of 1975–2000, with an average rate of 0.36 Mg/ha/yr, primarily resulting from regional climate variation and local land use and land cover change. Vegetation biomass accumulation accounted for 90.6% of the sink, while soil organic carbon loss before 1992 led to a lower net gain of carbon in the watershed, and after that soils became a small sink. Ecosystem carbon sink/source patterns showed a high degree of spatial heterogeneity. Carbon sinks were associated with forest areas without disturbances, whereas carbon sources were primarily caused by stand-replacing disturbances. It is critical to adequately represent the detailed fast-changing dynamics of land use activities in regional biogeochemical models to determine the spatial and temporal evolution of regional carbon sink/source patterns.