STRATEGY FOR OPTIMUM MANAGEMENT OF WATER PURIFICATION SYSTEM WITH CONSIDERATION OF TOTAL ENVIRONMENTAL LOAD AND COST-BENEFTT

为了最大限度地降低水库蓄水有机物负荷，通过现场测量和水质数值模拟，研究了亚磁曝气、选择性引水和滨海带植被等净水系统的性能。重点研究了溶解氧、营养盐和有机物的行为，建立了水质模型，考虑了水质平衡中涉及的各种生化过程，从而考虑了水质的季节变化。为了准确地再现现场数据，仔细确定了模型参数，其中考虑了与亚磁曝气相关的溶解氧平衡。该曝气系统是一种能够产生高溶解度微泡的微泡曝气装置。除曝气外，还考虑了选择性退出操作来调节溶解氧分布。各种类型的系统运行场景We…为了最大限度地提高净水性能，需要考虑更多的曝气和选择性回水。优化系统运行的基本思想是将水系统和大气环境的总环境负荷降至最低，并使成本效益最大化。在成本效益分析中，考虑了系统建设所需的初始成本和运行成本。提出了反映净水性能、成本和总环境负荷的参数，提出了曝气系统和选择性回水装置的优化运行方案。另一方面，进行了曝气系统间歇运行的现场试验，以期通过考虑氧气的溶解度和损失随热结构的季节变化而获得最佳的性价比运行。通过水质监测，找出间歇曝气系统的最佳运行方式，使能量消耗和二氧化碳排放降到最低。作为水质净化的另一种方式，通过对天然湖泊的实地考察，研究了滨海带植被的营养物质吸收性能，为今后几年的大坝水库管理提供了新的方向，为环境工程的应用提供了参考。此外，应用本研究成果，可以将河流流域的总环境负荷降至最低。较少

In order to minimize the organic compound loads on a reservoir impoundment, performance of water purification systems including hypolimnetic aeration, selective withdrawal and vegetation in littoral zones were investigated by making field measurement and a numerical simulation of water quality. Focus was placed on behaviors of dissolved oxygen, nutrients and organic matters.A water quality model was developed so that seasonal variation of water quality by considering various biochemical processes involved in the water quality balance. Model parameters were carefully determined so as to accurately reproduce the field data, where dissolved oxygen balance associated with hypolimnetic aeration was taken into consideration. The aeration system was a micro-bubble aerator unit that is able to generate fine bubbles with high solubility. In addition to the aeration, selective withdrawal operation was considered to regulate dissolved oxygen profile. Various types of system operation scenarios we … More re assumed with respect to aeration and selective withdrawal in order to maximize water purification performance. The basic idea for optimizing the system operation is to minimize total environmental loads not only on the water systems but also on the atmospheric environment as well as to maximize the cost-benefit. In the cost-benefit analysis, the initial cost necessary for the system construction and the running cost were taken into consideration. Parameters indicating the water purification performance, the cost and the total environmental loads were proposed so that an optimum strategy for the operation of the aeration system and the selective withdrawal devices was finally proposed.On the other hand, an in-situ experiment on intermittent operation of the aeration system was carried out in order to find the best cost-performance operation by considering solubility and loss of the oxygen that is dependent on the seasonalvariation of thermal structure. The best operation of the intermittent aeration system was found through water quality measurement, which is able to minimize the energy consumption and emission of carbon dioxide.As one of another ways of the water purification, nutrient intake performance of vegetation in littoral zone was investigated through a field survey in a natural lake.The results from the present research program are to provide a new direction of dam reservoir management that is useful for environmental engineering use in the next years. Additionally, the total environmental loads on a river catchment can be minimized by applying the present research results. Less