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241.
太湖藻对水-沉积物界面磷交换过程的影响 总被引:9,自引:2,他引:7
采用太湖梅梁湾沉积物和上覆水,以及从太湖水体中分离出的水华优势蓝藻(铜绿微囊藻)和常见绿藻(月芽藻), 室内模拟研究了这2种藻对太湖梅梁湾沉积物磷交换过程的影响. 结果表明:藻种的不同显著影响磷在水-沉积物界面的交换过程. 在沉积物和上覆水灭活条件下,铜绿微囊藻能够显著增加沉积物磷的释放量,引起上覆水中可溶性磷酸盐的增加;而月芽藻的存在没有引起沉积物中磷的明显释放,上覆水中可溶性磷酸盐一直保持在很低水平. 在低磷浓度的水体中,藻类会被诱导产生碱性磷酸酶,分解大分子可溶性有机磷,以满足自身生长的需要. 沉积物中各形态磷存在明显的转化作用,其中铁磷和碱提有机磷含量明显下降,而钙磷和酸提有机磷含量则大幅增加. 相似文献
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留神身边的“光污染”人们总是希冀着世界一片光明。可真要那样的话,世界也就大祸临头了。传说上古时代,天空突然出现了十个太阳,一时之间,天无分昼夜,人脚下无影,大地热浪滚滚,人人惶恐不安。这时出现了一位大英雄后羿,他用强弓一连射下了九个太阳,才把人们从水深火热之中拯救出来。看来光明太多,不见得就是件好事。在古希腊,有一次敌人庞大的舰队来犯,城邦里只剩下些妇孺。天才的物理学家阿基米德便让全城的妇女集中到海岸 相似文献
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The inactivation levels of Bacillus subtilis spores for various disinfection processes (ultraviolet (UV), TiO2 and UV-TiO2) were compared. The results showed that the inactivation effect of B. subtilis spores by UV treatment alone was far below that for bacteria without endospores. TiO2 alone in the dark, as a control experiment, exhibited almost no inactivation effect. Compared with UV treatment alone, the inactivation effect increased significantly with the addition of TiO2. Increases of the UV irradiance and Ti02 concentration both contributed to the increase of the inactivation effect. Lipid peroxidation was found to be the underlying mechanism of inactivation. Malondialdehyde (MDA), the degradation product of lipid peroxidation, was used as an index to determine the extent of the reaction. The MDA concentration surged surprisingly to 3.24 nmol/mg dry cell with the combination disinfection for 600 see (0.10 mW/cm2 irradiance and 10 mg/L TiO2). In contrast, for UV alone or TiO2 in the dark, the MDA concentration was 0.38 and 0.25 nmol/mg dry cell, respectively, under the same conditions. This indicated that both UV and TiO2 were essential for lipid peroxidation. Changes in cell ultrastructure were observed by transmission electron microscopy. The cell membrane was heavily damaged and cellular contents were completely lysed with the UV-TiO2 process, suggesting that lipid peroxidation was the root of the enhancement in inactivation efficiency. 相似文献
247.
应用以MPSS模型为基础的计算软件UV calc对某饮用水紫外线消毒反应器进行强度分布的计算,同时,采用枯草芽孢杆菌(ATCC9372)作为受试菌种进行生物验证.结果显示,在该反应器中理论计算数值总体上明显高于生物验证的数值,反应器中最低紫外剂量区域出现在2支灯管之间的反应器壁附近.另外,理论计算和生物验证的误差与流量、透光率具有相关性.在高流量、低透光率的情况下,理论计算的数值更接近于生物验证数值.相对于理论计算,生物验证是确定紫外线反应器剂量反应曲线的可靠方法. 相似文献
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A composting toilet using sawdust as a matrix has the potential to trap pathogens that might occasionally be contained in human
feces. Therefore, care should be taken when handling the sawdust. It should also be noted that pathogenic viruses tend to have stronger
tolerance than pathogenic bacteria. The fates of several species of coliphages, T4, , Q and MS2, in sawdust were investigated as
a viral model. The fates of coliphages were significantly different among them, and they changed in response to temperature and the
water content of the sawdust. As the results, T4 coliphage had the strongest tolerance and Q had the weakest one in sawdust. It was
estimated the days required to decrease virus to a safe level based on a risk assessment. According to the rates of Q and T4, 15 days
and 167 days were required respectively for a safe level of infection risk based on actually operated composting toilet condition. Thus,
it was significantly different depending on the species and sawdust conditions. 相似文献
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