Research On Urban Environmental Systems Health Assessment And Importance Analysis Under Multiple Scenarios

In recent years, with increasingly serious enviromental pollution, environmental problems has become a major concern. Urumqi is the biggest open city in the western China. Beause of itsgeographic location, the ecological environment of the city is vulnerable. Urumqi has abundant energy and mineral resources,but the local industrial energy consumption significantly increases year by year.Considering such acontradiction between vulnerable ecological environment and increasing environmental pollution arising from rapid industrial development, this paper analyzes the urban environment system of Urumqi, and provides the basis for urban environmental management.In this thesis, firstly, the theory and method of urban environmental systems health assessment areadvanced for Urumqi. From the statistical data fromyears2002to2011, the urban environmental health conditionof Urumqi isanalyzed under four scenarios,which are balanced development pattern, happiness city development pattern, preferment city devolpment pattern and tourist city development pattern. The results show that,the environmemt of Urumqi goes to positive in all four scenarios during the past10years. While the lowdegree indicates a slower covering speed, the city has hugepotential and development space.Importance analysis is valueable for system analysis, which is then conducted to seek for the major components affecting the urban systemof Urumqi.Due to the poor water environmental condition, this research select theHedong Sewage Treatment Plantto analyze the sewage treatment system of Urumqi. In this paper, based on stochastic reliability importance and AHP(Analytic Hierarchy Process), this study obtainsinteresting resultsforthe urban sewage treatment system.During the reliability importance analysis, each component gets200random-generated faiure rates under a normal distrubution. The considered reliability importance includesstructural importance(SI), Birnbaum importance(BI), criticality importance(CI), and modification importance(MI). Bytaking the data into four importance methods, the conclusion that the MI is the best choicecan be drown. This research also studysmultiple factorsinthe Urumqiurban sewage treatment system under multiple scenarios by weighting importance(WI), based on the results fromAHP and reliability importance analysis. To reducethe influence of subjective factors,500random weights are applies to the WI method, and then components1#to3#are identified as week components of the system.The proposed urban environmental health assessment and importance analysisapproaches canidentifythe major components constrainingenvironemntal protection and water utilization in Urumqi. The results can also provide referenceforurban environmental management in arid regions.