Evaluation of long-term water quality management policy effect using nonparametric statistical methods

IF 0.8 4区工程技术 Q4 ENGINEERING, CHEMICAL

Membrane Water Treatment Pub Date : 2019-09-01 DOI:10.12989/MWT.2019.10.5.339

K. Jung, J. Ahn, Sohyun Cho, Y. Lee, K. Han, Dong-seok Shin, Kyunghyun Kim

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引用次数: 5

Abstract

Long term water quality change was analyzed to evaluate the effect of the Total Maximum Daily Load (TMDL) policy. A trend analysis was performed for biochemical oxygen demand (BOD) and total phosphorus (TP) concentrations data monitored at the outlets of the total 41 TMDL unit watersheds of the Nakdong River in the Republic of Korea. Because water quality data do not usually follow a normal distribution, a nonparametric statistical trend analysis method was used. The monthly mean values of BOD and TP for the period between 2004 and 2015 were analyzed by the seasonal Mann-Kendall test and the locally weighted scatterplot smoother (LOWESS). The TMDL policy effect on the water quality change of each unit watershed was analyzed together with the results of the trend analysis. From the seasonal Mann-Kendall test results, it was found that for BOD, 7.8 % of the 41 points showed downward trends, 26.8 % and the rest 65.9% showed upward and no trends. For TP, 51.2% showed no trends and the rest 48.8% showed downward trends. From the LOWESS analysis results, TP began to decrease in most of the unit watersheds from mid-2010s when intensive chemical treatment processes were introduced to existing wastewater treatment plants. Overall, for BOD, relatively more points were improved in the main stream compared to the points of the tributaries although overall trends were mostly no trend or upward. For TP, about half of the points were improved and the rest showed no trends.

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非参数统计方法评价长期水质管理政策效果

分析了长期水质变化，以评估总最大日负荷（TMDL）政策的效果。对大韩民国NakdongRiver总共41个TMDL单元流域出口监测的生化需氧量（BOD）和总磷（TP）浓度数据进行了趋势分析。由于水质数据通常不遵循正态分布，因此使用了非参数统计趋势分析方法。通过季节性Mann-Kendall检验和局部加权散点图平滑器（LOWESS）分析了2004年至2015年期间BOD和TP的月平均值。结合趋势分析结果，分析了TMDL政策对各单位流域水质变化的影响。根据季节性Mann-Kendall测试结果，发现BOD在41个点中有7.8%呈下降趋势，26.8%，其余65.9%呈上升趋势，没有趋势。TP方面，51.2%没有趋势，其余48.8%呈下降趋势。根据LOWESS分析结果，从2010年代中期开始，当现有污水处理厂采用强化化学处理工艺时，大多数单位流域的TP开始减少。总的来说，就BOD而言，与支流的点相比，干流的点得到了相对更多的改善，尽管总体趋势大多没有趋势或上升。对于TP，大约一半的分数得到了改善，其余的没有任何趋势。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Membrane Water Treatment ENGINEERING, CHEMICAL-WATER RESOURCES

CiteScore

1.90

自引率

30.00%

发文量

审稿时长

>12 weeks

期刊介绍： The Membrane and Water Treatment(MWT), An International Journal, aims at opening an access to the valuable source of technical information and providing an excellent publication channel for the global community of researchers in Membrane and Water Treatment related area. Specific emphasis of the journal may include but not limited to; the engineering and scientific aspects of understanding the basic mechanisms and applying membranes for water and waste water treatment, such as transport phenomena, surface characteristics, fouling, scaling, desalination, membrane bioreactors, water reuse, and system optimization.