Dynamic transport of sewer sediments and water quality transformation characteristics under different rainfall intensities
ZHANG Jin1, SHI Xuan2, CHEN Xiao-qing1, HAN Jian-shuang3, JIN Peng-kang2, SONG Ji-na1
1. School of Energy and Environmental Engineering, Hebei University of Engineering, Handan 056038, China; 2. Institute of Human Settlements and Building Engineering, Xi'an Jiaotong University, Xi'an 710049, China; 3. School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
Abstract:The scouring of sediment deposits in sewer system constitutes a critical factor in overflow pollution. By integrating rainfall intensity variations, stratified anti-scouring characteristics, and dynamic pollutant transport, a dynamic transport model was developed to evaluate stratified sediment scouring under different rainfall intensities and its impact on water quality transformation. Experimental results demonstrate significant disparities in sediment scouring efficacy across varying rainfall intensities. Under light rainfall conditions, the scouring rate measured 6.04m3/h, primarily removing superficial sediment layers. Moderate and heavy rainfall events induced substantial enhancement of flow shear forces, with pipe discharge reaching 71.08m3/h during intense precipitation, capable of mobilising larger particles from underlying sediment strata. A pronounced "initial phase effect" was observed across all rainfall intensities, characterised by rapid pollutant concentration peaking during precipitation onset. Under heavy rainfall, sulphate concentrations surged to 17.89mg/L within 1min before stabilising at 8.95mg/L, while Total Chemical Oxygen Demand (TCOD) exhibited a swift ascent to 2106.3mg/L followed by stabilisation at 1056.6mg/L. In contrast, light rainfall conditions yielded markedly lower peak values of 10.29mg/L for SO42- and 1100.60mg/L for TCOD, though similarly demonstrating rapid initial concentration escalation followed by gradual stabilisation.
张劲, 石烜, 陈晓晴, 韩剑霜, 金鹏康, 宋吉娜. 不同降雨强度下管道沉积物的动态运移及水质转化特征[J]. 中国环境科学, 2025, 45(5): 2503-2512.
ZHANG Jin, SHI Xuan, CHEN Xiao-qing, HAN Jian-shuang, JIN Peng-kang, SONG Ji-na. Dynamic transport of sewer sediments and water quality transformation characteristics under different rainfall intensities. CHINA ENVIRONMENTAL SCIENCECE, 2025, 45(5): 2503-2512.
[1] 徐祖信,徐晋,金伟,等.我国城市黑臭水体治理面临的挑战与机遇[J]. 给水排水, 2019,55(3):1-5,77. Xu Z X, Xu J, Jin W, et al. Challenges and opportunities of black and odorous water body in the cities of China [J]. Water & Wastewater Engineering, 2019,55(3):1-5,77. [2] 唐建国,张悦,梅晓洁.城镇排水系统提质增效的方法与措施[J]. 给水排水, 2019,55(4):30-38. Tang J G, Zhang Y, Mei X J. Strategies and methods for improving the quality and efficiency of the urban drainage system [J]. Water Wastewater & Engineering, 2019,55(4):30-38. [3] Rathnayake U, Faisal Anwar A H M. Dynamic control of urban sewer systems to reduce combined sewer overflows and their adverse impacts [J]. Journal of Hydrology, 2019,579:124150. [4] Regueiro-Picallo M, Suárez J, Sañudo E, et al. New insights to study the accumulation and erosion processes of fine-grained organic sediments in combined sewer systems from a laboratory scale model [J]. Science of the Total Environment, 2020,716:136923. [5] Okabe S, Odagiri M, Ito T, et al. Succession of sulfur-oxidizing bacteria in the microbial community on corroding concrete in sewer systems [J]. Applied and Environmental Microbiology, 2006,73:971- 980. [6] Fan C Y, Field R, Pisano William C, et al. Sewer and tank flushing for sediment, corrosion, and pollution control [J]. Journal of Water Resources Planning and Management, 2001,127(3):194-201. [7] Muynck W M d, Belie N D, Verstraete W. Effectiveness of admixtures, surface treatments and antimicrobial compounds against biogenic sulfuric acid corrosion of concrete [J]. Cement & Concrete Composites, 2009,31:163-170. [8] 陈雅欣.合流制污水管网沉积物冲刷的溢流污染规律与调控研究[D]. 西安:西安建筑科技大学, 2022. Chen Y X. Characteristics and regulation of overflow pollution from combined sewer sediment [D]. Xi'an: Xi'an University of Architecture and Technology, 2022. [9] Barone L, Pilotti M, Valerio G, et al. Analysis of the residual nutrient load from a combined sewer system in a watershed of a deep Italian lake [J]. Journal of Hydrology, 2019,571:202-213. [10] Meng D, Jin W, Chen K, et al. Cohesive strength changes of sewer sediments during and after ultrasonic treatment: The significance of bound extracellular polymeric substance and microbial community [J]. Science of the Total Environment, 2020,723:138029. [11] Campisano A, Modica C, Creaco E, et al. A model for non-uniform sediment transport induced by flushing in sewer channels [J]. Water Research, 2019,163:114903. [12] Montes C, Kapelan Z, Saldarriaga J. Predicting non-deposition sediment transport in sewer pipes using random forest [J]. Water Research, 2021,189:116639. [13] Shi X, Zhang J, Wang Q, et al. A new perspective of sediment layering scour and migration under the coupled effects of particle distribution and bio-viscosity–cavitation erosion [J]. Science of the Total Environment, 2024:175929. [14] 韩剑霜,石烜,张建锋,等.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 J S, Shi X, Zhang J F, et al. Starting law and pollution contribution characteristics of stratified sediment scouring in sewage pipes [J]. China Environmental Science, 2023,43(10):5208-5213. [15] Cheng P D, Zhu H W, Zhong B C, et al. Transport mechanisms of contaminants released from fine sediment in rivers [J]. Acta Mechanica Sinica, 2015,31(6):791-798. [16] 张青文,余健,李天兵.雨水管道沉积物污染初期冲刷效应及初期雨水量研究[J]. 给水排水, 2020,56(7):119-124. Zhang Q W, Yu J, Li T B. Study on first flush effect and initial rainwater volume in storm sewer sediments pollution [J]. Water & Wastewater Engineering, 2020,56(7):119-124. [17] Chen Y X, Shi X, Jin X, et al. Characteristics of overflow pollution from combined sewer sediment: Formation, contribution and regulation [J]. Chemosphere, 2022,298:134254. [18] Zhao N, Ngo H H, Li Y, et al. A comprehensive simulation approach for pollutant bio-transformation in the gravity sewer [J]. Frontiers of Environmental Science & Engineering, 2019,13:1-12. [19] Jaiswal R K, Ali S, Bharti B. Comparative evaluation of conceptual and physical rainfall–runoff models [J]. Applied Water Science, 2020,10(1):48. [20] Liu Y, Ni B J, Sharma K R, et al. Methane emission from sewers [J]. Science of the Total Environment, 2015,524-525:40-51. [21] Szeląg B, Łagód G, Musz-Pomorska A, et al. Development of rainfall-runoff models for sustainable stormwater management in urbanized catchments [J]. Water, 2022,14(13):1997. [22] 王晓婷.城市雨洪模拟与雨水管网优化研究——以上海中心城商务区为例[D]. 上海:上海师范大学, 2019. Wang X T. Urban stormwater simulation and pipe network optimization---A case study in Shanghai central city business district [D]. Shanghai: Shanghai Normal University, 2019. [23] Kim M G, Bartos M. A digital twin model for contaminant fate and transport in urban and natural drainage networks with online state estimation [J]. Environmental Modelling & Software, 2024,171: 105868. [24] 薛甜,石烜,赵楠,等.污水管网不同汇流条件下沉积物运移分布规律[J]. 中国给水排水, 2023,39(7):107-113. Xue T, Shi X, Zhao N, et al. Migration and distribution of sediment in sewage sewer network under different confluence conditions [J]. China Water & Wastewater, 2023,39(7):107-113. [25] GB/T 28592-2012降雨量等级[S]. GB/T 28592-2012 Grade of precipitation [S]. [26] 刘素玮.人工快速渗滤系统处理保定市初雨径流污染试验研究[D]. 保定:河北农业大学, 2023. Liu S W. Experimental study on the treatment of initial rain runoff pollution in Baoding city by artificial rapid infiltration system [D]. Baoding: Hebei Agricultural University, 2023. [27] 胡将军,李海彩,邵庆军,等.多级跌水充氧式沟渠连通生态塘污水处理效果及优化模拟试验[J]. 农业工程学报, 2015,31(3):242-248. Hu J J, Li H C, Shao Q J, et al. Influence and parameter optimization simulation experiment on sewage treatment based on multi-level drop aeration ditch and ecological pond [J]. Transactions of the Chinese Society of Agricultural Engineering, 2015,31(3):242-248. [28] Liu Y, Fang H H P. Influences of extracellular polymeric substances (EPS) on flocculation, settling, and dewatering of activated Sludge [J]. Critical Reviews in Environmental Science and Technology, 2003, 33(3):237-273. [29] Comte S, Guibaud G, Baudu M. Relations between extraction protocols for activated sludge extracellular polymeric substances (EPS) and EPS complexation properties: Part I. Comparison of the efficiency of eight EPS extraction methods [J]. Enzyme and Microbial Technology, 2006,38(1):237-245. [30] Ou Q, Xu Y, Li X, et al. Interactions between activated sludge extracellular polymeric substances and model carrier surfaces in WWTPs: A combination of QCM-D, AFM and XDLVO prediction [J]. Chemosphere, 2020,253:126720. [31] Voinova M V, Rodahl M, Jonson M, et al. Viscoelastic acoustic response of layered polymer films at fluid-solid interfaces: continuum mechanics approach [J]. Physica Scripta, 1999,59(5):391. [32] Sweity A, Ying W, Ali-Shtayeh M S, et al. Relation between EPS adherence, viscoelastic properties, and MBR operation: Biofouling study with QCM-D [J]. Water Research, 2011,45(19):6430-6340. [33] Gurdak E, Dupont-Gillain C C, Booth J, et al. Resolution of the vertical and horizontal heterogeneity of adsorbed collagen layers by combination of QCM-D and AFM [J]. Langmuir, 2005,21(23): 10684-10692. [34] 魏复盛.水和废水监测分析方法.第4版[M]. 中国环境科学出版社, 2002. Wei F S. Water and waste water monitoring and analysis method (fourth edition) [M]. China Environmental Science Press, 2002. [35] 岳天祥.资源环境数学模型手册[M]. 第一版.北京:科学出版社, 2003. Yue T X. Manual of mathematical model of resources and environment [M]. First edition. Beijing: Science Press, 2023. [36] Shi X, Ngo H H, Sang L, et al. Functional evaluation of pollutant transformation in sediment from combined sewer system [J]. Environmental Pollution, 2018,238:85-93. [37] 赵楠.城市污水管网污染物迁移转化模拟研究[D]. 西安:西安建筑科技大学, 2021. Zhao N. Simulation research on pollutant transformation in urban sewer networks [D]. Xi'an: Xi'an University of Architecture and Technology, 2021. [38] 朱婉宁,李萌,张旭东,等.基于短期在线监测的污水管网降雨入流入渗分析[J]. 给水排水, 2021,57(7):117-122. Zhu W N, Li M, Zhang X D, et al. RDII analysis of sewer system based on short-term online monitoring [J]. Water & Wastewater Engineering, 2021,57(7):117-122.