基于组合权重的模糊数学法对水质的评价

Fuzzy Mathematical for Water Quality Assessment Based on Combination Weighted

水质综合评价为水环境治理提供指导性建议,是水环境管理的重要参考.而水质各个指标权重的确定一直是研究的重点和难点.运用数学方法中的离差平方和最小原理,建立一个确定指标权重的优化模型,结合超标加权法和熵值法两种方法所确定的权重值,得到一个组合权重,并将其应用于模糊数学法对水质进行评价.以铁岭市环保监测站所得的辽河流域马仲河门脸断面2008年—2012年五年数据为基础进行实例分析,选取门脸断面中的溶解氧、COD、BOD、氨氮、总磷、石油类、挥发酚7项作为评价指标,应用上述模糊数学法进行水质等级分析,得到五年的水质为:2008、2009两年为Ⅴ类水质;2011年水质最好,达到Ⅰ类;2010年为Ⅴ类,2012年为Ⅳ类水质.并使用主成份分析法和综合指数模型两种方法进行验证,结果表明这种模型有较高的精度和可靠性.所以,模型也可为其它的权重确定方法在求解权重值时提供一定参考.

Water quality comprehensive assessment can support a guiding advice and an im- portant reference for water environment management. The index weights＇ determination~ as the emphasis and difficulty, is increasingly valued by exports. This article showed an optimiza- tion model based on a mathmatical theory - the minimal Deviation square summation. Both excessive weighted method and entropy method were used in this optimization model, which gave a combination weighted matrix. Taking the example of MenLian section on MaZhong River, a tributary of LiaoHe River, the data of MenLian section from 2008 to 2012 was applied into this optimization model for water quality assessment. Data was monitored by Environ- ment protection monitoring station of TieLing city. Seven sets of indexs, including dissolved oxygen, COD, BOD, ammonia nitrogen, total phosphorus, petroleum and volatile phenol were chosen as assessment indexs. An index system formed from these seven indexs was applied into the optimization fuzzy mathematical method for MenLian section water quality assesssment. Based on the analysis of MenLian section water quality category, it can be found that： the water quality grade of year 2008 and year 2009 belonged toy class, year 2011 was the highest level, Iclass, and the year of 2010 belonged to Vclass, 2012 belonged to IVclass. Principal componment analysis （PCA） and complex index model were used to verify this optimization model. The result showed that the optimization model based on the principle of minimal Deviation square summation has a high accuracy and reliability. It is feasible when applied into fuzzy mathematical method for water quality assessment. This model can also supply a reference for other weight determination methods to obtain weight matrix.