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181.
Fenton组合工艺处理焦化厂生化出水的应用研究 总被引:2,自引:1,他引:1
比较了Fenton氧化、Fenton氧化+活性炭及Fenton氧化+生物活性炭工艺对焦化厂生化出水的处理效果.结果表明,Fe2+、H2O2的投加量分别为56、27.2 mg/L时,Fenton氧化工艺对水样的UV254、颜色度(VIS380)、COD和总氰均有较好的去除效果;Fenton氧化+活性炭工艺在有效去除UV254、VIS380、COD和总氰的同时,能强化活性炭的吸附效果,并能显著提高水样的生化性能;Fenton氧化+生物活性炭工艺能有效去除UVM254,VIS380、COD与总氰,使出水达到<污水综合排放标准>(GB 8978-1996)一级标准. 相似文献
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183.
Renyan Duan Chao Wang Xiao-an Wang Zhihong Zhu Hua Guo 《Russian Journal of Ecology》2009,40(7):501-509
We compared differences in plant species diversity between conifer (Pinus tabulaeformis) plantations and natural secondary forests in the middle of the Loess plateau. The goal of the study was to examine the differences
in the effect of stand development on species diversity and in species responses to changes between forest types and between
forest layers. To clarify the effects of differences in forest management, we emphasized the functional types of plant species
occurring in each forest type. The result as follow: (1) The H′ and S of tree layer were significantly lower in natural conifer forest than old conifer and secondary forest, but were not different
compared with mid aged conifer forest. The H′ and S of shrub layer were significantly lower in mid aged conifer forest compared with other forest types. The H′ of herb layer showed no significant differences in the four forest types. The evenness index (J′) of tree layer of mid aged conifer forest was lower than other forest communities and its J′ of shrub layer was highest although its richness of shrub layer was lower than in the other forest types. (2) The analysis
of β diversity index also indicated large differences between conifer plantations and natural forests. Although the tree layer
species were similar in old plantation and natural conifer forests, they differed greatly between the natural conifer and
secondary forests. The natural conifer and secondary forest species composition in shrub layer differed significantly from
those in plantation and secondary plots. Tree species were significantly less common in plantations than in abandoned coppice
forests. Species composition in the herb layer of different forest types was similar. (3) The management of P. tabulaeformis plantations alters plant species composition considerably; the number of sub tall-tree species is increased in old aged conifer
forest, especially species dispersed by animals. Plantation management appears to affect ecological processes through seed
dispersal. From the perspective of management, the change in the structure and composition of the canopy in plantations could
affect the behavior of dispersers and regeneration. 相似文献
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185.
长江下游氮、磷含量变化及其输送量的估计 总被引:69,自引:10,他引:59
根据在1997和1998年内对长江干流大通站河水的3次采样分析,结合该站1962~1990年的水质资料,对长江下游N、P含量变化及其输送量进行研究.总氮、总磷的平均含量分别为1.6~2.2m g·L-1和0.11~0.15m g·L-1,N 以NO-3 -N 为主,约占76% ,其余主要为溶解有机氮和颗粒氮;P以颗粒态为主,占95% 以上.从5、6月到8月,NO-3-N含量是逐渐降低的,DON含量有较大幅度的上升,PN、PP及TP含量也有所增高.与历史资料相比,长江大通站溶解无机氮(DIN)和PO3-4-P含量还在不断上升,N、P含量的上升与流域化肥施用量变化趋势一致.1998年夏季洪水期间,约有79.95万tN和8.36万tP从大通站向下游输送,其中DIN与生物有效磷(BAP)比值远高于浮游植物生长的P限制值. 相似文献
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188.
Qiaohong Sun Dongxian Kong Chiyuan Miao Qingyun Duan Tiantian Yang Aizhong Ye Zhenhua Di Wei Gong 《Environmental monitoring and assessment》2014,186(9):5663-5679
Climate change has impacts on both natural and human systems. Accurate information regarding variations in precipitation and temperature is essential for identifying and understanding these potential impacts. This research applied Mann–Kendall, rescaled range analysis and wave transform methods to analyze the trends and periodic properties of global and regional surface air temperature (SAT) and precipitation (PR) over the period of 1948 to 2010. The results show that 65.34 % of the area studied exhibits significant warming trends (p?<?0.05) while only 3.18 % of the area exhibits significant cooling trends. The greatest warming trends are observed in Antarctica (0.32 °C per decade) and Middle Africa (0.21 °C per decade). Notably, 62.26 % of the area became wetter, while 22.01 % of the area shows drying trends. Northern Europe shows the largest precipitation increase, 12.49 mm per decade. Western Africa shows the fastest drying, ?21.05 mm per decade. The rescaled range analysis reveals large areas that show persistent warming trends; this behavior in SAT is more obvious than that in PR. Wave transform results show that a 1-year period of SAT variation dominates in all regions, while inconsistent 0.5-year bands are observed in East Asia, Middle Africa, and Southeast Asia. In PR, significant power in the wavelet power spectrum at a 1-year period was observed in 17 regions, i.e., in all regions studied except Western Europe, where precipitation is instead characterized by 0.5-year and 0.25-year periods. Overall, the variations in SAT and PR can be consistent with the combined impacts of natural and anthropogenic factors, such as atmospheric concentrations of greenhouse gases, the internal variability of climate system, and volcanic eruptions. 相似文献
189.
Zhengqing Cai Xiao Zhao Jun Duan Dongye Zhao Zhi Dang Zhang Lin 《Frontiers of Environmental Science & Engineering》2020,14(5):84
190.
Yanqing Duan Aijuan Zhou Xiuping Yue Zhichun Zhang Yanjuan Gao Yanhong Luo Xiao Zhang 《Frontiers of Environmental Science & Engineering》2021,15(1):12