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971.
972.
973.
针对微污染水水质不稳定,CODMn波动较大的问题,本研究构建了3套中试规模的以"前置生态氧化塘、两级水平潜流湿地和表流湿地为核心、后置沉水植物塘"为工艺的多级人工湿地-塘组合系统(处理水量230 L·d-1,分别命名为S1、S2和S3).在3种进水浓度条件下(原水、稀释2倍和稀释1.3倍后的水体,分别作为S1、S2和S3系统的进水),考察了3套湿地-塘系统各单元对实际微污染河水中CODMn的处理效果,并采用高通量测序等方法解析了S1系统湿地单元微生物群落分布特征.研究结果表明,3套系统的平均出水COD较进水有着非显著的升高,从升高的程度来看,S2>S3>S1.污染浓度相对最高、运行时间最长的S1系统对COD有着更好的净化效果.相较于S2系统,S3系统更高的进水浓度有利于COD去除.S1和S2系统的二级水平潜流湿地较其他单元有着较好的COD去除作用,平均去除率分别为18.60%和26.52%.S3系统的表流湿地较其他单元有着较好的COD去除作用,平均去除率为8.92%.微生物群落分析结果表明,S1系统的一级、二级水平潜流湿地中细菌丰度和多样性沿程提高,两个单元所富集的相同优势菌群包括α-变形菌纲、γ-变形菌纲和拟杆菌纲,与COD降解有关的菌属分别包括unclassified_f__Burkholderiaceae、unclassified_c__Alphaproteobacteria、norank_f__Blastocatellaceae和norank_f__Saprospiraceae、红细菌属.表流湿地中细菌丰富度进一步升高,但生物多样性有所减少,其中蓝菌属和norank_c__Actinobacteria可能与表流湿地出水COD升高有关.本研究为大型河口湿地-塘复合生态系统处理微污染地表水时工作重心由浓度削减向污染物释放控制的转移提供了宝贵的工程经验. 相似文献
974.
西南国际河流水资源状态及开发中的问题 总被引:2,自引:0,他引:2
西南国际河流流域地形复杂、海拔高、人口稀少,人均水资源量丰富,出境水量大,水质好,目前开发利用程度低,具有广阔的开发利用前景。但随着我国加入WTO,经济和社会发展融入国际的步伐加快,对国际河流的开发和利用也必然要按照国际法或国际惯例。首先对西南国际河流水资源的自然状态,我国在各自流域中的地位、开发利用状态以及存在的问题进行了论述;然后讨论国际河流开发中应注意的问题和准则;最后,根据可持续发展的原则和各个河流的特点,提出建议:应该充分认识到我国西南国际河流地区生态环境脆弱和社会经济发展水平较低的状态,今后应以水资源保护为主,优先发展航运和旅游业,合理开发水能资源。同时应积极参与国际合作与交流,与相关国家共同开发流域水资源,促进流域经济社会的可持续发展。 相似文献
975.
Peng Hu Changsheng Guo Yan Zhang Jiapei Lv Yuan Zhang Jian Xu 《Frontiers of Environmental Science & Engineering》2019,13(4):56
976.
Seasonal changes in river water chemistry and in soil atmospheric CO2 concentrations at two depths and drainage water solute composition at two upland peaty podzol sites in north east Scotland were monitored over 12 months. the CO2 concentrations were controlled by changes in soil temperature and moisture status. Highest CO2 concentrations were observed in late summer 1988 when both soil temperatures and the moisture status of the soils were high. Then maximum CO2 concentrations of 4% (v/v) were recorded for one of the sites. No significant correlations between seasonal changes in soil CO2 concentrations and river water solute composition were observed. Nevertheless the field results and laboratory experiments indicated that in upland areas, where soils with acid surface horizons are common, soil CO2 substantially influences river water chemistry at baseflow, increasing the pH and cation concentration of the soil water draining into the river. the results suggest that transfer of carbon as dissolved CO2 in drainage water is a significant pathway for CO2 transfer to the atmosphere. 相似文献
977.
I. V. Molchanova E. N. Karavaeva L. N. Mikhailovskaya V. N. Pozolotina L. V. Lobanova 《Russian Journal of Ecology》2003,34(4):236-241
The contents of 90Sr and 137Cs and the pattern of their redistribution in the soil and plant cover of floodplain ecosystems have been assessed. It is shown that the radionuclide distribution across the floodplain and along the river flow is determined by the formation of a barrier to their migration near the river channel, at which less mobile 137Cs accumulates. The soil and plant cover of the central floodplain are enriched with 90Sr. Differences in radionuclide migration in floodplain soils and their input into plants are determined by the relationship between the processes of their immobilization and migration with soil water. 相似文献
978.
979.
The lower Roanoke River in North Carolina, USA, has been regulated by a series of dams since the 1950s. This river and its floodplain have been identified by The Nature Conservancy, the US Fish and Wildlife Service, and the State of North Carolina as critical resources for the conservation of bottomland hardwoods and other riparian and in-stream biota and communities. Upstream dams are causing extended floods in the growing season for bottomland hardwood forests, threatening their survival. A coalition of stakeholders including public agencies and private organizations is cooperating with the dam managers to establish an active adaptive management program to reduce the negative impacts of flow regulation, especially extended growing season inundation, on these conservation targets. We introduce the lower Roanoke River, describe the regulatory context for negotiating towards an active adaptive management program, present our conservation objective for bottomland hardwoods, and describe investigations in which we successfully employed a series of models to develop testable management hypotheses. We propose adaptive management strategies that we believe will enable the bottomland hardwoods to regenerate and support their associated biota and that are reasonable, flexible, and economically sustainable. 相似文献
980.