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Mechanism of Water Pollution of Urban Streams and Methods for Recovering the Water Quality

城市河道水污染机理及水质恢复方法

基本信息

批准号：
01550400
负责人：
HAYAKAWA Norio
金额：
$ 1.47万
依托单位：
Nagaoka University of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1989
资助国家：
日本
起止时间：
1989 至 1990
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-01550400/
关键词：
Urban Stream Water Pollution BOD Dissolved Oxygen Sediment Oxygen Demand Water Quality Simulation 水質シミュレ-ション水質モデル

项目摘要

Streams flowing through urban areas receive high pollutant loads from their small drainage areas. Therefore, the water quality of urban streams is generally vary sensitive to the urbanization and the construction of a sewerage system. In this study, we carried out the water quality observation of the Kaki River, which is a typical urban stream flowing through Nagaika City, to investigate the mechanism of water purification in the river. On the basis of the observational results, we proposed a mathematical model to describe BOD, DO and SS in the river.Two important processes of the purification are revealed from repeated observation of the water quality of the river. One is that the settling of the suspended materials is the dominant process of the apparent purification. The other is that the Sediment Oxygen Demand (SOD) affects the oxygen balanc of the river water. Experiments on the SOD were made using core-sampled sediments. The results showed that the SOD is expressed as a product of the sediment BOD and the rate constant which shows an Arrhenius-type dependence on the water temperature.A simulation model was developed to describe BOD, DO and SS in a river. In order to distinguish the settling process separately, the particulate BOD and the dissolved BOD are considered as model variables. The SOD, resuspension of the sediments and release of the dissolved BOD are taken into account as model processes. All model constants including the rate constant of the SOD were evaluated by experiments. The model successfully reproduced the distribution of BOD, SS and DO in the Kaki River.The model analysis confirms that the settling of the particulate matter is the dominant process of the apparent purification in the river. Cleaning of deposited sediments as well as reducing pollutant loads due to sewage construction is effective for the improvement of the water quality in urban streams.

流经城市地区的河流从其小的排水区接收高污染物负荷。因此，城市河流的水质一般对城市化和污水处理系统的建设敏感。在本研究中，我们进行了水质观测的加木河，这是一个典型的城市河流流经长协市，调查在河流中的水净化的机制。在此基础上，提出了描述黄河水体BOD、DO和SS的数学模型，并通过对黄河水质的反复观测，揭示了黄河水体净化的两个重要过程。一是悬浮物的沉降是表观净化的主导过程;二是沉积物需氧量（SOD）对水体氧平衡的影响。利用沉积物岩心样品进行了SOD的实验研究。结果表明，超氧化物歧化酶（SOD）是沉积物BOD和速率常数的乘积，速率常数与水温呈Arrhenius型关系，建立了描述河流BOD、DO和SS的模拟模型。为了区分沉降过程，颗粒BOD和溶解BOD被认为是模型变量。模型中考虑了超氧化物歧化酶（SOD）、沉积物再悬浮和溶解态BOD的释放。通过实验求出了包括SOD速率常数在内的所有模型常数。该模型成功地再现了Kaki河中BOD、SS和DO的分布，模型分析证实了颗粒物的沉降是Kaki河表观净化的主导过程。清除沉积物以及减少污染物的负荷，由于污水建设是有效的改善水质的城市河流。