污水再生回用对银川市水资源承载力的影响

立足干旱地区新兴城市银川,构建了基于污水再生回用的银川市水资源承载力系统动力学模型,以污水再生回用量增长率为决策变量,设置了4种提高水资源承载力的情景方案并进行模拟预测,以人口、GDP、缺水量、COD排放总量及污水回用工程投资占GDP比重等水资源承载力特征指标作为输出变量。结果表明,方案4即近期污水再生回用增长率为15%、远期污水再生回用增长率为24%是最符合促进人口增长的发展模式;加速经济发展,增加供水量,减少污染物排放及具有良好的回用工程投资比的银川市污水再生回用发展方案,能够使银川市水资源承载力达到最优水平。

Impact of municipal sewage regeneration and circulated use on carrying capacity of water resources in Yinchuan City

The present paper takes Yinchuan( Ningxia) water-resource exploitation system as a case study sample for reconstruction of the municipal sewage regeneration. As a matter of fact,the paper has taken up its engineering construction obligations as the city’s water resource exploitation goals based on the 8 state variables,8 rate variables,44 supplementary variables,20 stable functions and 15 sewage reclamation and constant reuse variables from the following aspects,such as those of social subsystem,economic subsystem and environmental subsystem,which are embedded in the sewage reclamation and reuse functions.The reason for the regeneration and reuse of the municipal sewage goals is that they can win the public recognition as an effective reclaimed way though the water pollution elimination and open source with its water quality reclaimed should be made enough constantly stable and reliable. It is only built up on the said constantly reliable enough foundation that the items can be turned up to be one of the most reliable and confident measures to improve the water resources,especially in such an arid waterdeficient areas as Ningxia. And,for the above purposes,it would be necessary to build up and take up the growth rate of the sewage reclamation and reuse as the decision variable to simulate the 4 scenarios in improving the water resources with enough water-storing capability in accordance with the corresponding urban planning of the system dynamics model to meet the predetermined demands of high reliability through repeated testing and social evaluation. Therefore,the simulation should be carried out with the features of water resource carrying capacity,such as the population concerned,the GDP size,the water shortage evaluation and the needed probability,with the total COD discharge and the investment amount in the sewage reuse project to the corresponding GDP size as the output variables. The above said statistics results can help to show that,according to the developing trend of scheme 1,the capacity of the reclaimed water supply and water quality demands has to be satisfied,and the capacity of the water environment bearing capacity of the region has to be strengthened basically. And,in so doing,even if the water resources carrying capacity of scheme 2 and scheme 3 can be realized and improved remarkably from the point of view of water quantity and quality,they can just partly satisfy the water need of the entire region. Nevertheless,the situation of water resources is still in need to be supported by greater amount of investment in the reuse. And,plan 4,namely,the growing need for the sewage reclamation and reuse in the near future remains lower than 15%,and the growing need for these wage reclamation and reuse in the long run is higher,say,24% than the time being. All this should be taken as the most suitable exploitation model for the population growth stimulation,so as to accelerate its economic development,water supply increase and pollutant discharge reduction. Thus,the optimized level of the city planning of sewage reclamation and the water reuse in the city can only be satisfied by a good-enough investment ratio of recycling projects,so as for it to reach its needed water resources bearing capacity.