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.
| Translated title of the contribution | Starting law and pollution contribution characteristics of stratified sediment scouring in sewage pipes |
|---|---|
| Original language | Chinese (Traditional) |
| Pages (from-to) | 5208-5213 |
| Number of pages | 6 |
| Journal | Zhongguo Huanjing Kexue/China Environmental Science |
| Volume | 43 |
| Issue number | 10 |
| State | Published - 2023 |