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991.
煤层气开发是一个时短、线长、面广的工程活动,具有单井产气量低、井网密度大、降压排水等独特特征,对生态环境有一定的影响。文中分析了煤层气开发过程中钻井废液、排采水等污染物的性质,结果表明,钻井废液中COD浓度较高,为1 985.5 mg/L,As、Cr、Cu、Zn、Mn、Fe、Pb等重金属含量均在污水综合排放二级标准之内;排采水中含有较高的COD、重金属、盐浓度,经自然沉降后,COD、重金属浓度有所降低,而盐浓度变化不大;考察了煤层气开发对土壤环境质量的影响,发现钻井过程对土壤盐渍化没有影响,但土壤中As含量有所增加。在此基础上,提出钻井废液、排采水及污染土壤的具体防治对策,为煤层气开发污染治理提供理论依据与技术支持。 相似文献
992.
基于新型反应器的好氧颗粒污泥的稳定性控制 总被引:1,自引:0,他引:1
为避免好氧颗粒污泥随着粒径和密度的变化屡次出现其稳定性失去控制,导致好氧颗粒污泥系统运行失败的状况发生,开发了一种新型反应器能够很好地控制好氧颗粒污泥的粒径和密度.新反应器结合旋流器的使用提供了2种排泥方式,其一是短的沉淀时间,将大粒径和高密度的颗粒污泥存留在反应器中;其二是一种专有的污泥排除工艺,选择出反应器内潜在的可能存在进一步粒径增长和密度扩大从而破坏反应器运行稳定的大粒径和高密度的颗粒,并将其排除.以上2种方式保证了反应器内颗粒污泥的粒径长期维持在300~1 000μm,进而维持整个系统的稳定性.对新型反应器生成的颗粒污泥进行动力学参数的测定,该工艺所形成颗粒的能量维持系数为0.08~0.10,就新陈代谢活动的代谢途径而言,相比传统颗粒污泥系统发生较大改变,维持新陈代谢活动所消耗COD较传统工艺偏高.另外,出水水质COD的降解率平均达到92%,氨氮降解率平均达到60%. 相似文献
993.
994.
基于MODIS数据的太湖蓝藻变化与水温关系研究 总被引:3,自引:1,他引:2
以太湖为研究区,基于2008年4~12月的60景EOS—MODIS 1B遥感影像数据。利用NDVI算法结合目视判读解译了水华分布变化的基本信息,通过劈窗算法反演太湖湖面水温,发现在2008年太湖蓝藻生长、暴发、衰退周期中。水华面积的大小与湖面均温值之间关系密切:在20℃以下时表层水温与太湖蓝藻生长暴发或沉寂消亡具有明显的相关性;20℃-30℃时水华的面积大小受到湖面温度和其他因素的共同影响,容易发生大规模蓝藻暴发:30℃以上时过高的表层水温会对蓝藻的上浮聚集具有一定抑制作用:太湖蓝藻全年消亡的临界温度与其初始生长的临界温度相比更低。研究同时发现太湖湖面温度的空间差异是影响蓝藻水华分布迁移的重要因素之一。 相似文献
995.
Total pollution effect of urban surface runoff 总被引:3,自引:1,他引:2
LUO Hongbing LUO Lin HUANG Gu LIU Ping LI Jingxian HU Sheng WANG Fuxiang XU Rui HUANG Xiaoxue 《环境科学学报(英文版)》2009,21(9):1186-1193
For pollution research with regard to urban surface runo , most sampling strategies to date have focused on di erences in land usage.
With single land-use sampling, total surface runo pollution e ect cannot be evaluated unless every land usage spot is monitored.
Through a new sampling strategy known as mixed stormwater sampling for a street community at discharge outlet adjacent to river,
this study assessed the total urban surface runo pollution e ect caused by a variety of land uses and the pollutants washed o from the
rain pipe system in the Futian River watershed in Shenzhen City of China. The water quality monitoring indices were COD (chemical
oxygen demand), TSS (total suspend solid), TP (total phosphorus), TN (total nitrogen) and BOD (biochemical oxygen demand). The
sums of total pollution loads discharged into the river for the four indices of COD, TSS, TN, and TP over all seven rainfall events were
very di erent. The mathematical model for simulating total pollution loads was established from discharge outlet mixed stormwater
sampling of total pollution loads on the basis of four parameters: rainfall intensity, total land area, impervious land area, and pervious
land area. In order to treat surface runo pollution, the values of MFF30 (mass first flush ratio) and FF30 (first 30% of runo volume)
can be considered as split-flow control criteria to obtain more e ective and economical design of structural BMPs (best management
practices) facilities. 相似文献
996.
Seasonal variation of nitrogen and phosphorus in Xiaojiang River—A tributary of the Three Gorges Reservoir 总被引:1,自引:1,他引:0
Zhe Li Jinsong Guo Man Long Fang Fang Jinping Sheng Hong Zhou 《Frontiers of Environmental Science & Engineering in China》2009,3(3):334-340
A yearlong monitoring program in the backwater area of Xiaojiang River (XBA) was launched in order to investigate the eutrophication
of backwater areas in tributaries of the Yangtze River in the Three Gorges Reservoir (TGR) in China, starting after the impoundment
water level of the TGR reached 156 m. From March 2007 to March 2008, the average concentration of total nitrogen (TN) and
total phosphorus (TP) were (1553±484) μg·L−1 and (62±31) μg·L−1, respectively. The mean value of chlorophyll was (9.07±0.91) μg·L−1. The trophic level of XBA was meso-eutrophic, while the general nutrient limitation was phosphorus. The results indicated
that XBA has a strong ability to purify itself and has non-point source pollution from terrestrial runoff. The variation of
TN/TP ratio was caused by a variation in TN rather than in TP when TN/TP < 22. N-fixation from cyanobacteria occurred and
became an important process in overcoming the nitrogen deficit under a low TN/TP ratio. When TN/TP ⩾ 22, the variation of
TP affected the TN/TP ratio more significantly than TN. The increase of TP in XBA was caused mainly by particulate phosphorus,
which could originate from a non-point source as adsorptive inorganic forms after heavy rainfall and surface runoff. An increase
in the river’s flow could also contribute to an unstable environment for the growth of phytoplankton. 相似文献
997.
Mingqiang Huang Weijun Zhang Liqing Hao Zhenya Wang Li Fang Ruihong Kong Xiaobin Shan Fuyi Liu Liusi Sheng 《环境科学学报(英文版)》2010,22(10):1570-1575
Smog chamber experiments were performed to investigate the composition of products formed from photooxidation of aromatic
hydrocarbon ethylbenzene. Vacuum ultraviolet photoionization mass spectrometer and aerosol time-of-flight mass spectrometer were
used to measure the products in the gas and particle phases in real-time. Experimental results demonstrated that ethylphenol,
methylglyoxal, phenol, benzaldehyde, and 2-ethylfurane were the predominant photooxidation products in both the gas and particle
phases. However, there were some di erences between detected gas phase products and those of particle phase, for example,
2-ethylfurane, ethylglyoxylic acid, nitroethylbenzene, 3,4-dioxopentanal and ethyl-nitrophenol were only existing in the particle-phase.
The possible reaction mechanisms leading to these products were also discussed and proposed. 相似文献
998.
999.
1000.
有机物的荧光特性被广泛用来解析其在水体中的来源与分布。荧光光谱技术具有灵敏度高、选择性好、且不破坏样品结构的优点,非常适合用来研究有机物的化学和物理性质。运用三维荧光指纹技术对N市某城市湖泊的有机污染类型和污染程度进行了监测。实验结果表明,三维荧光指纹技术能有效揭示城市湖泊中有机物的动态变化。从七月份到十二月份,N市某城市湖泊的主要有机污染类型为内源污染;其中七月份到九月份还兼有外源污染,而十月份到十二月份基本没有外源污染。实验期间,此城市湖泊水体中C lass III(类蛋白)荧光峰的荧光强度在416.10~298.76之间,C lass I(类腐殖酸)荧光峰的荧光强度在128.90~123.19之间,此城市湖泊的内源污染远大于外源污染。 相似文献