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971.
由于小型景观水体的体量和再生水补水措施的施行,其水质随环境和入水水质的变化和富营养化过程较大型水体快。由EFDC模型和WASP模型耦合建立小型浅水景观湖生态动力学模型,用实测水质数据进行参数率定与验证,可实现小型景观水体水质变化趋势的模拟,为水质管理提供决策支持。在此基础上,对民主湖在几种水质保障方案下1年的水质变化进行了模拟预测和对比,结果表明,作为富营养化程度表征的叶绿素a在空间和时间分布上均存在一定的规律性,夏季由于温度升高,叶绿素a浓度较高,说明藻类等浮游植物迅速增殖,是水质恶化水华暴发的高发期,而采取加大湖水水力循环和改善入口水质的控制方案,可使水质得到良好保障。 相似文献
972.
构建阶式生物接触氧化反应器处理富营养化太湖水源水,对其净水效能进行研究。结果表明,在优化工况条件下,阶式生物氧化反应器的三阶对太湖水源水中DOC的累积去除率分别为34.4%、40.2%和47.5%,对BDOC的总去除率为68.4%,除生物降解外,填料拦截、生物吸附絮凝等物理、化学作用对去除原水中的DOC仍有重要作用。DOC分子量分级表明,太湖源水中含量最大的是分子量〈500Da的DOC,含量最小的是分子量在5k~500Da间的DOC。阶式生物接触氧化反应器对分子量〈500 Da的DOC的去除率在60%以上,而出水中5k~500 Da区间的DOC含量相比原水增加近1倍。 相似文献
973.
在给水曝气生物滤池内置粉末活性炭,对比分析其对各工艺单元水质净化效果的影响,确定给水曝气生物滤池内置粉末活性炭的作用与最佳投加量,研究表明,给水曝气生物滤池将活性炭截留在滤池内,大幅度提高了粉末活性炭利用率,部分未饱和粉末活性炭通过反冲洗排入后续常规处理系统,作为生物载体仍能够进一步发挥生物强化作用。当粉末活性炭的投加量为8 mg/L时,砂滤出水氨氮、CODMn、浊度和色度均值分别为:0.02 mg/L,1.82 mg/L0,.46 NTU和6度,去除率分别达到99.6%、71.2%、99.1%和80.6%,出水指标达到《生活饮用水卫生标准(》GB5749-2006)和《饮用净水水质标准(》CJ94-2005)规定的标准。与常规工艺相比,投加量降低了20%~60%。 相似文献
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976.
在反复实验的基础上建立了运用Bran+Luebbe AutoAnalyzer 3流动注射分析仪快速测定地表水中总氰化物的分析方法。结果表明,该方法与传统的分光光度法相比,具有自动进样、分析速度快、测定成本低等优点。与经典的分析方法相对照,结果无显著性差异,能够满足大批量地表水监测的要求。在测试系统中引入了恒温槽,进一步提高了测试的精密度和准确度。 相似文献
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979.
Siyuan Bi Zhanrui Huang Fanghong Nie Xiaobo Wang Lijun Sun 《Journal of environmental science and health. Part. B》2019,54(5):416-423
T-2 toxin (T-2), one of the naturally occurring mycotoxins, often accumulates in aquatic animals from contaminated feed. Shrimp (n?=?30 per group) were fed with different concentrations (0, 0.5, 1.5, 4.5 and 13.5?mg kg?1) of T-2 for 20?days. Changes in histopathology, fatty acid and water distribution of shrimp muscle were analyzed. Histopathology of shrimp muscle showed dose-dependent marked degenerative and necrotic changes on exposure to dietary T-2. The T-2 significantly (P?<?0.05) affected the muscle fatty acid composition. ∑SFA, ∑MUFA and ∑PUFA initially decreased and then increased slowly in the high-dosed groups. C16:0, C18:1n-9 and C18:2n-6 were the main saturated fatty acid (SFA), monounsaturated fatty acid (MUFA) and polyunsaturated fatty acid (PUFA), respectively. Also, T-2 significantly affected water distribution in shrimp muscle. High doses of T-2 reduced free water content, resulting in a reduction in the water holding capacity and hence changes to the shrimp muscle quality. Collectively, these results illustrated that T-2 significantly affects the fatty acid and water distribution, and also muscle histopathology, all of which would result in a reduction in the quality and nutritional value of shrimp. 相似文献
980.
Lilian D. Steckert William E. Furtado Gabriela T. Jerônimo Scheila A. Pereira Gabriel F. A. Jesus José Luiz P. Mouriño 《Journal of environmental science and health. Part. B》2019,54(4):237-246
Fish may bioaccumulate contaminants from the aquatic environment and extend them to the food chain provoking risks to human health. This study evaluated the microbiological parameters of the pond´s water and trace elements concentrations in samples of water, sediment, feed and muscle of farmed Nile tilapia used for human consumption in southern Brazil. A total of 240 fish were collected from 12 tilapia farms. Sediment, tank water and dry ration used in the animals' diet were collected for analysis. Analysis were performed by Energy Dispersion X-ray Fluorescence (EDXRF), Inductively Coupled Plasma Mass Spectrometer (ICP-MS), Induced Coupled Plasma Optical Emission Spectrometer (ICP-OES), and Atomic Absorption Spectrometer (AAS-VGA). In addition, the microbiological analysis of the water was carried out. The concentrations of Se, I, Fe, Cu and Zn in fish muscle were higher than the recommended by the Brazilian legislation, considering the advised daily intake for adults. The arsenic element had concentrations above the limit stipulated by the present Brazilian legislation, observed in all samples of muscle, sediment and tank water highlighting a possible environmental and fish contamination by the toxic element. Moreover, the arsenic concentration in the water presented a positive correlation (ρ?=?0.33) with arsenic in the muscle, suggesting that tilapia is a good environmental bioindicator, once they properly reflect the levels of arsenic in the water. It is suggested to perform an arsenic speciation for quantification of the inorganic form and accurate assessment of the degree of toxicity in the muscle samples and risks it can bring to human health. Regarding the other potentially toxic elements (Hg, Pb and Cd), and microbiological analysis of water it was verified that the consumption of the fish in question does not raise risks, since the values are within a quality benchmark established by law. The concentration of total and fecal coliforms in pond´s water in the facilities was in agreement with the microbiological indexes required by the legislation of CONAMA class II. Western region presented the lowest concentrations of fecal coliforms when compared to the other regions. There was no significant difference in the microbiological counts of total heterotrophic bacteria, Vibrio spp. and Pseudomonas spp. among the regions. 相似文献