Starting law and pollution contribution characteristics of stratified sediment scouring in sewage pipes
HAN Jian-shuang1, SHI Xuan1,2, ZHANG Jian-feng1, HUI Yi-lian1, JIN Peng-kang1,2
1. School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; 2. School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, Xi'an 710049, China
Abstract：To explore the distribution characteristics of pollutants in the vertical section of sewer sediment, the mechanism of layered erosion initiation and pollution contribution characteristics of sediment under gradient erosion intensity were revealed. It could be an important foundation for scientific control of combined overflow pollutants (CSO). In this study, a pilot sewer system which could simulate the sediment erosion process was established. And based on the theory of layered distribution of sewer sediment, the characteristics of particle size, carbon and nitrogen pollutants were revealed. The results show that the theoretical critical shear stress under different layered particles increases from 0.038N/m2 to 0.261N/m2 with the increase of particle size. As the flow shear force increased from 0.1N/m2 to 0.3N/m2, the contribution rate of sediment of TCOD increased from 6.4% to 46.3%; the contribution rate of TN increased from 25.3% to 40.6%; and TP decreased from 42.9% to 25.1%. Moreover, in comparison with the attachment content of various pollutants, as the flow intensity increased, the proportion of suspended solids that start flushing was the highest among organic pollutants. It can be concluded that, the particle size has a significant impact on the distribution of pollution load of pollutants, and the distribution of pollution load has a correlation with the concentration changes of overflow pollutants caused by water flow erosion. Thus, clarifying the flow intensity and concentration changes of overflow pollutants caused by layered sediment erosion in pipelines can help effectively control water pollution.
韩剑霜, 石烜, 张建锋, 惠依莲, 金鹏康. 污水管道沉积物分层冲刷的起动规律及其污染贡献特性[J]. 中国环境科学, 2023, 43(10): 5208-5213.
HAN Jian-shuang, SHI Xuan, ZHANG Jian-feng, HUI Yi-lian, JIN Peng-kang. Starting law and pollution contribution characteristics of stratified sediment scouring in sewage pipes. CHINA ENVIRONMENTAL SCIENCECE, 2023, 43(10): 5208-5213.
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