State-of-the-art management models for lakes and reservoirs

This paper reviews current models that can be used in lake management, mainly for eutrophication and wetland areas. The latter type of model, in particular, has developed rapidly during the past decade due to the increasing importance of wetlands as traps for nutrients originating from non-point sources. The experience gained in lake modelling since the mid-1980s can be summarized as follows: (i) 3-D hydrodynamic models are available today but are not necessarily the right answer to a given modelling problem (dependent on data availability); (ii) models with a wide spectrum of complexities are available which make it possible to select a type of model appropriate to available data; and (iii) several models with general applicability are available, yet it is necessary to tailor a model for each individual case (generally based on experience from previous model studies). The experience gained by the use of the so-called Glumsø model on 25 case studies led to the same conclusion: modifications are needed in the original model for each new case study to allow for the specific characteristics of the lake modelled. Lake management models have been developed for eutrophication, oxygen depletion, various specific pollution problems, thermocline formation, acidification, and the use of wetlands to cope with non-point pollution, particularly for removal of nitrogen by denitrification. An overview of available models, including their shortcomings, is given in the text. We have experience in using models for many different environmental problems of lakes, but it is necessary to improve these models by including more ecological components. These improvements are discussed in relation to the most recent experiences in the use of models with dynamic structures.     

Management issues of the Lake Peipsi/Chudskoe region

Lake Peipsi is the fourth largest lake in Europe and the largest international lake in Europe. Lake Peipsi is shallow, eutrophic, biologically very productive and is bordered by many wetland areas along its coasts. Large peat deposits in the Lake Peipsi basin are protected under national legislation. The lake is most important as a resource for recreation and fisheries. The fish stock in Lake Peipsi is one of the richest in Europe. The most critical environmental issues for the Peipsi watershed are eutrophication and unregulated fishing in the lake. During the Soviet period, large collective farms dramatically accelerated eutrophication. Despite the drop in fertilizer use during the last 10 years and a decrease in the number of domestic animals in the watershed, the impact of the earlier agricultural pollution is still significant. Untreated sewage has also been dumped in the Narva River tributary as a result of an international dispute concerning water supply and wastewater treatment. People living in the Lake Peipsi region have faced traumatic changes as a result of the re‐establishment of the border between Russia and Estonia in 1992. The establishment of an international border on the waters of the lake has resulted in fishermen losing access to many of their traditional fishing areas. Political and economic transformations of the last 10 years have seriously interrupted information exchange between different institutions and organizations concerned with the health of the lake. The Centre for Transboundary Cooperation facilitates international communication and cooperation between the Estonian and Russian governments and promotes public participation in environmental, social and economic development and decision‐making. The centre is in the process of guiding the development of a watershed management plan for the Lake Peipsi watershed and a vision for watershed development that is truly sustainable.     

改性玄武岩岩棉去除富营养化水体中磷的研究

对废弃玄武岩岩棉通过改性去除富营养化水中的磷,进行了试验研究.结果表明,采用超声波加热、浓度为1%的NaOH改性的岩棉对磷的去除效果最佳,当水体中总磷的浓度为0.58～0.85mg/L时,在改性岩棉用量为每7g/100mL、吸附时间为90min、pH为7.2的试验条件下,总磷的去除率为50%以上,使用后的岩棉经再生可重复使用.     

关于太湖污染底泥生态疏浚工程的探讨

目前太湖面临着严峻的富营养化问题，太湖污染底泥生态疏浚工程已经开始启动，但是关于太湖清淤的问题，专家们仍存在不同的见解。针对目前存在的几种观点，认为首先要对太湖疏浚进行前期研究，然后开展太湖示范工程，对污染底泥的空间分布规律、水质影响程度和机制、疏浚和处置技术、环境和生态效应等关系的科学问题进行系统深入的研究，从而为污染底泥的疏浚和处置技术提供理论和实践依据。     

利用富营养化水体生物膜降解微囊藻毒素研究

采用一种自行设计的简便生物膜采集装置，自然培养和收集富营养化湖泊——武汉东湖水体中不同深度（20cm和100cm）处的生物膜，研究不同水深、相同培养时间以及同一水深、不同培养时间所得生物膜在有氧条件下对微囊藻毒素（MC）的降解过程。结果表明，东湖水体生物膜对MC的降解经历了2～3d的延滞期，约11d后可使之降解完全；20cm水深处培养的生物膜对MC的降解速率快于100cm水深处培养的生物膜；随着附着生物膜载玻片数量的增多，对MC的降解速率加快；对MC的降解效果与生物膜的培养时间密切相关，按对MC降解速率的快慢排序为：14d〉21d〉7d；在降解MC的过程中，溶液的pH值持续上升。经分析，生物降解是去除东湖水体中MC的主要途径之一。     

大型调水对受水湖体富营养化关键因子的影响

开展了引江济太和引江济巢工程对太湖和巢湖饮用水源地富营养化关键指标TN和TP的影响研究。结果表明,太湖贡湖湾超过Ⅲ类地表水标准的指标为TN、BOD5和TP,引水期长江及入湖的TN和TP浓度基本高于贡湖湾;巢湖东半湖超过Ⅲ类地表水标准的指标为TP,长江水的TP和TN年均浓度均高于巢湖东半湖;在长江现状调水水质下,引长江水入太湖和巢湖不能有效降低两湖水源地TN和TP浓度。可见,外调水源虽增加了水量,却不能从根本上解决富营养化问题,必须坚持水量与水质并重,持之以恒地进行入湖及内源污染治理,从根本上实现湖体及水源地生态恢复。     

以水化硅酸钙为基质的人工湿地系统除磷研究

添加水化硅酸钙作为人工湿地的基质,旨在强化湿地系统对磷的去除能力,减轻水体富营养化.采用模拟试验系统考察了水化硅酸钙粒径、投加量及水力停留时间对除磷效果的影响.结果表明,在水化硅酸钙粒径为4目、投加量为80 g时系统达到最佳的除磷效果,一个月后去除率稳定在75%左右,与对照人工湿地相比,去除率可提高20%以上;停留时间越长,系统对磷的去除效果越好,停留时间为4 d的去除率比停留时间为2 d和1 d的分别高约5%和20%;水化硅酸钙对植物的生长和除磷能力有明显的促进作用.同时,湿地植物代谢可以有效控制水化硅酸钙本身对出水pH的影响,使水体pH值稳定在8.2左右.     

再生水景观水体富营养化因素的垂直变化特征

合肥市环城水系是以再生水为唯一补水水源的城市景观水体,选择环城水系中具有代表性的银河水体,对河道水体中的磷、氛、溶解氧和pH值的垂直分布及变化规律进行了研究。结果表明,沿水体的深度方向,总磷、氨氮、正磷酸盐浓度逐渐增高,pH值和溶解氧浓度则逐渐降低。溶解氧和pH值可间接反映藻类的生长情况和密度,可作为水华暴发的简便预警指标。