Three-Dimension Mathematical Model Of Total Phosphor In The Reservoir And Application

Some reservoirs are polluted as the development of society. Among these problems on pollution, eutrophication is the regular and most harmful water environment issue, especially for the reservoirs in some urban areas, which are polluted greatly and cannot work as water sources for city water supply. Take Beijing GuanTing reservoir as one of the examples. So it is an important task and scheme to control the eutrophication of reservoirs.Water eutrophication is that excessive nitrogen , phosphor and other nutrition materials enter into water .As a result of that, alga and other hydrophytes in the water propagate excessively, resulting in the changes of the transparence of water body and the dissolved oxygen (DO) in water and the depravation of water quality. Finaly the functions and ecological environments of reservoirs would be destroyed and the usage of water is affected.According to the investigation of OECD (the Organization of Economy Cooperation and Development), about 80% water eutrophication is effected by phosphor element and about 10% water eutrophication has direct relation to nitrogen and phosphor elements. And another 10% is relative with nitrogen and other elements. So every country in the world has taken many measures to limit the drain of nitrogen and phosphor substance to water. And in 1986, the unitednation of Switzerland issued the act "forbiddance to use phosphorous scour" to control the export of nitrogen and phosphor substance to water body.Most of water eutrophication is limited by phosphor element, because water will be eutrophicated under the condition of the nitrogen-phosphor scale (N/P) between 10 and 15, which is propitious to the propagation of alga. The content of nitrogen in water is not easily controlled as alga and other water biology could absorb all kinds of nitrogen in water or air and live in the environments with nitrogen element. According to above presentation, phosphor plays an important pole in the formation of water eutrophication. That is to say. if we can control the phosphor content in water, i.e. the scale of phosphor and phosphor, we can control the trend of water eutrophication. So the phosphor element is the limited factor in water eutrophication and many reservoirs are phosphor-control reservoirs.In order to control the eutrophication effectively, protect the water quality in reservoirs, and utilize water resources scientifically, it is essential to investigate the phosphor content, distribution, and the laws of transformation. Up to now, the presentation about the mechanism of phosphor transformation and mathematic models follows into two aspects.One is the analysis of phosphor transformation in water, most of which only considers the pollutant pervasion and transformation and the role of source items. As the resolutions rarely consider the pollutant transformation and resolvability and so on factors caused by chemic and biology factors, biology pole in phosphor transformation and movement is not neglectable.The other is about the mathematic models for phosphor transformation and movement. Now the existing models are 0, 1 dimensions and there are rarely 2 and 3 dimension models reversely. The zero-dimension models is only proper inthe condition where water is uniform and concentric, and the 1 -or-2 dimension models only appreciate for the condition where only one or two water change in the three directions, X, Y, Z.Based on the above analysis, this paper pays more attention to the effect of biology on the phosphor transformation and movement and it is one innovative point of this paper to consider the role of biology. At the same time, we also establish the general three-dimension models for the phosphor transformation and movement in reservoir water body, which is also an innovative point of this paper.The source of phosphor in water can be classified into outer-source phosphor and intra-source phosphor. And the aggravation substance of reservoirs is the main intra-source phosphor. The outer-source phosphor is mainly from the air sedimentation, the industrial and...