苏州市再生水利用影响因素识别及潜力评估

Identification of influencing factors and potential assessment of the reclaimed water utilization in Suzhou City

以苏州市为研究区,对其污水处理以及再生水利用能力现状进行了分析。选取25项影响苏州市再生水利用量的指标因素,并根据2008—2020年相关统计资料,运用BP-DEMATEL(backpropagation decision-making trial and evalvation laboratory)模型识别出影响再生水利用的关键驱动因素以及关键特征因素,在此基础上构建差分GM(1,N)预测模型,评估苏州市再生水利用潜力。结果显示:污水处理投资、排水设施投资、居民家庭用水量、全年水资源总量、万元GDP用水量等5项因素为关键驱动因素,污水排放量、污水处理量、污水处理能力、城市用水人口4项因素为关键特征因素,均与苏州市再生水利用发展密切相关。GM(1,N)预测模型拟合结果精度较高,平均相对误差为0.22%,预期至2025年苏州市再生水利用潜力可达到59630.52万m^(3)。

Suzhou is a typical economically developed city in southern Jiangsu.With the rapid economic development,the consumption of water resources is also very large,and the resulting discharge of a large number of industrial and domestic sewage leads to a serious water shortage.Strengthening the utilization of reclaimed water plays a very important role in alleviating the contradiction between supply and demand of urban water resources and improving water pollution,which is conducive to realizing the sustainable utilization of water resources.In order to further improve the utilization rate of reclaimed water in Suzhou,form an advanced and suitable model of reclaimed water utilization and promote the development of reclaimed water enterprise,the present situation of sewage treatment is analyzed and water utilization capacity is reclaimed in Suzhou.Selected 25 factors affecting the amount of reclaimed water resources,and based on the relevant statistical data from 2008 to 2020,a BP neural network model was constructed to obtain the weight matrix between input value and output value.It replaced the direct correlation matrix obtained by questionnaire survey or expert scoring in the traditional DEMATEL model.The key driving factors and characteristic factors which affect the development of reclaimed water utilization in Suzhou were identified.On this basis,the GM(1,N)grey prediction model is established,and the historical data of identified key factors and their extended data were taken as the data of relevant factors to predict the potential of reclaimed water utilization in Suzhou.The results show that:investment in sewage treatment and drainage facilities,water consumption of households,total annual water resources and water consumption of 10 thousand RMB GDP were the key driving factors,which were the main factors affecting the development of reclaimed water utilization in Suzhou;sewage discharge,the amount and capacity of sewage treatment,and urban water consumption population were the key characteristic factors,which had a direct impact on the development of reclaimed water utilization in Suzhou.Therefore,in order to promote the development of Suzhou city reclaimed water utilization,it is needed to increase investment for sewage treatment,promote the treatment scale and technology level,on the other hand to increase drainage facilities investment,improve the urban sewage collection pipe network,increase the rate of sewerage,perfect supporting facilities,improve reclaimed water pipe network coverage.To make renewable water resources have more reasonable allocation,GM(1,N)prediction model basically met all kinds of tests and could be used for medium and long term prediction of reclaimed water consumption.The average relative error was 0.22%,and the maximum error was 6.55%.By 2025,the utilization potential of reclaimed water in Suzhou can reach 596.3052 million m^(3),which had a huge space for improvement compared with the current utilization level.