The Application Of Projection Pursuit Evaluation Model In Reclaimed Water System

Recent years,with the rapid development of industry and urbanization,water usage of cities are growing fast,thus cause serious imbalance of water supply and demand.According to statistics,there are 400 out of 655 cities that are in shortage of water resources,110 have severe problems.Meanwhile,wastewater discharge increases and many of which discharge into river and lake system without any treatment,thus cause pollution of water body and damage of water quality,seven great rivers are moderately polluted on the whole,and there is lack of control measures for these pollution.Water resources shortage and damage of water quality have become the major factors against sustainable development.In face of the increasingly grim situation,the central government raised open source policy timely,supply urban water source by exploit unconventional water resources.The �water law� clearly puts forward to strengthen the city centralized sewage treatment,encourage the use of recycle water and improve the utilization rate of recycling sewage,2011 central document and the central water conservancy work conference proposed to vigorously promote sewage reuse treatment.It's an important measure of relieve water shortage pressure,accomplish regional cycle use of water resources,promote water saving and protection,realize energy saving and emission reduction targets as well as promote the construction of water ecological civilization and implement the most stringent water management system.Based on recycle water system evaluation,this paper mainly discussed its components,operating mode and index evaluation system.Combing the project of �Research on the framework of the preferential policies for the treatment of sewage� taken by Development Research Center of the Ministry of water resources,In order to promote the good development of the recycle water system,the necessity of the evaluation of the recycle water system is discussed.Through a large number of field research and data collections,the basic level of recycle water system evaluation development in China was found out,and several cities such as Beijing and Tianjin can be a great guidance for other cities.Taking Xi'an city as an example,this paper carried out the comprehensive evaluation of the recycle water system.First,collect basic data of recycle water usage,including the plant distribution,processing capacity,pipeline network,main water users and water price of recycle water.Secondly,projection pursuit method was chosen as the basic method of recycle water system evaluation,and then genetic algorithm was used to analyze the result of evaluation,which is realized through MATLAB genetic algorithm toolbox.Finally,conclusion that the development level of recycle water system evaluation is intermediate level was found out,and studied the main restricting factors facing the development of recycle water system in Xi'an City,and put forward the corresponding improvement measures,which has a certain guiding significance for the balanced development of recycle water system evaluation in Xi'an city.Therefore,it is very important to carry out the comprehensive evaluation of the recycle water system in China.