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861.
国内外水环境管理体制对比分析 总被引:8,自引:0,他引:8
水环境管理体制建设是一项复杂的系统工程;即使在发达国家,水环境管理模式也随着认识水平的提高与需求的不断变化,处于逐步完善的过程。本文收集了国际上在水环境管理方面比较有代表性的国家,包括美国、英国、法国、荷兰、加拿大、澳大利亚、前苏联、日本、韩国、以色列与印度等水环境管理体制方面的资料,系统分析了这些国家在国家级、流域级与区域级的水环境管理体制与主要采取的水环境管理模式;并针对我国水环境管理体制的结症所在,提出了我国水环境管理体制改革所需遵循的基本原则。 相似文献
862.
本文从宏观角度对博州水资源的开发利用作了详细的研究。通过分析博州现行的水资源利用状况,找出以往开发利用中存在的问题及原因,运用结构分析方法,借助系统动力学(SD)建模手段,构造了博州水资源系统的宏观调控结构分析模型。通过观察和比较模型的输出结果,最后提出以从农业生产中挖潜节水为主攻方向,来解决博州水资源开发利用中现存的各种问题和作为今后制定各种水资源政策的参考。本研究将区域水资源开发利用问题归结为系统宏观控制问题,并在方法上作了一些探索。 相似文献
863.
Xu Zhengyong Yang Zhaohui Zeng Guangming Xiao Yong Deng Jiuhua 《Frontiers of Environmental Science & Engineering in China》2007,1(1):43-48
The nitrogen removal mechanism was studied and analyzed when treating the ammonium-rich landfill leachate by a set of sequencing
batch biofilm reactors (SBBRs), which was designed independently. At the liquid temperature of (32 ± 0.4)°C, and after a 58-days
domestication period and a 33-days stabilization period, the efficiency of ammonium removal in the SBBR went up to 95%. Highly
frequent intermittent aeration suppressed the activity of nitratebacteria, and also eliminated the influence on the activity
of anaerobic ammonium oxidation (ANAMMOX) bacteria and nitritebacteria. This influence was caused by the accumulation of nitrous
acid and the undulation of pH. During the aeration stage, the concentration of dissolved oxygen was controlled at 1.2–1.4
mg/L. The nitritebacteria became dominant and nitrite accumulated gradually. During the anoxic stage, along with the concentration
debasement of the dissolved oxygen, ANAMMOX bacteria became dominant; then, the nitrite that was accumulated in the aeration
stage was wiped off with ammonium simultaneously.
Translated from Acta Scientiae Circumstantiae, 2006, 26(1): 55–60 [译自: 环境科学学报] 相似文献
864.
简述了近十几年来原子吸收光谱在我国石油化学工业领域的应用及进展,全文分原油及其加工产品,化工物品,催化剂添加剂等几类样品阐述。 相似文献
865.
后所煤矿矿井水处理与利用 总被引:1,自引:0,他引:1
云南后所煤矿始建于1969年,建有四对生产矿井,设计生产能力0.95Mt/a,矿井涌水量达3.3Mm~3/a,这些矿井水如直接外排,不仅污染了环境,同时也浪费了水资源。后所煤矿近几年抓矿井水的处理利用,取得了很好的效果。 相似文献
866.
通过对满足选点标准的5个调查点和7个空气质量质控对照点,一年四个季度每季度抽样5d以上连续自动监测环境空气质量的科研性监测方式,共获取各类有效数据约20万个,从而以定量的方式确定了重庆市主要公共集会场所,交通道路和风景旅游区的环境空气质量水平。 相似文献
867.
868.
XUYi SUNWei WANGDong-sheng TANGHong-xiao 《环境科学学报(英文版)》2004,16(4):585-588
Water samples collected from early March 2001 to the end of April 2002 at the branch of Pearl River around the Guangzhou City were analyzed for its micro-polluted characteristics. The coagulation behavior of polyaluminum chlorides(PACIs) was then examined focusing on the effect of primary water quality and speciation distribution. The results showed that PACIs exhibit better coagulation efficiency than alum in accordance with the different speciation.The turbidity removal property of PACIs is evidently better than alum at low dosage. While in neutral zone(about 6.5--7.5), the turbidity removal of PACIs decreases owing to the restabilization of particles at higher dosage. The organic matters in raw water exhibit marked influence on coagulation. In acidic zone, organic matters complex with polymer species and promote the formation of flocs. With an increase in pH, the complexation of organics with polymer species gradually decreases, and the removal of organics mainly depends on adsorption. The effect is evidently improved with the raise of B value. 相似文献
869.
Blood flow across the atrioventricular valves and outflow tracts was measured in 55 normal fetuses and 32 fetuses with haemoglobin (Hb) Bart's disease between 18 and 26 weeks of gestation. The mean velocities remained unchanged in both normal and affected fetuses over the gestations studied. The volume flow across both atrioventricular valves and outflow tracts increased as the gestation advanced in both normal and affected fetuses, but was significantly higher in affected than in normal fetuses. The same magnitude of increased flow was found in both hydropic and non-hydropic fetuses with Hb Bart's disease. These findings suggest that fetuses with severe and long-standing anaemia have a remarkable cardiac compensatory mechanism for the maintenance of tissue oxygenation. In response to anaemia and circulatory loading, the cardiac chambers and outflow tracts enlarge proportionately up to twice the normal values. Because of this response and the operation of the Frank-Starling mechanism, the heart is able to maintain a normal mean velocity of propulsion and the net output is increased to two to three times that in normal fetuses. Hydropic changes in these anaemic fetuses appear unrelated to cardiac failure as cardiac failure is not observed at the time that hydropic changes develop. 相似文献
870.
综述了近些年来国内外微生物絮凝剂的发展概况,并对微生物絮凝剂的絮凝机理进行了探讨.分别介绍了单菌株生物絮凝剂、复合型生物絮凝剂、有效微生物群以及微生物絮凝剂的生物学研究,对微生物絮凝剂的发展趋势及其应用情况进行了分析. 相似文献