排水管道沉积物控制的研究进展

Research progress on the control of sediments in the drainage pipe

  • 摘要: 排水管道沉积物雨天受冲刷而造成的河湖水体污染,已成为当前我国水环境质量持续改善面临的困境之一。深入了解管道沉积物及其沉积机制对水体污染治理至关重要。综述了管道沉积物的形成与特性,微生物或沉积物中胞外聚合物(extracellular polymeric substance,EPS)的主要组分和相关性质对沉积物抗冲刷特性的影响。结果显示:排水管道沉积物主要是由污水携带的固体颗粒发生沉降而形成,主要包含底层粗颗粒沉积物、有机层和生物膜3类。由于沉积物中富含微生物并可分泌EPS,而EPS的黏性能显著增加管道沉积物的抗冲刷性。通过控制或降解沉积物EPS中的多糖组分,可降低沉积物的抗冲刷性能,有望为控制管道沉积物淤积提供新思路。目前国内外控制管道沉积物淤积的方法主要包括离线和在线水力冲刷或机械清淤。今后的研究方向应着力在真实的排水管网中系统地研究沉积物耐冲刷特性及其影响因素,进而提出更为有效的控制技术。

     

    Abstract: The water pollution of rivers and lakes caused by the erosion of drainage pipeline sediments in rainy days has become a dilemma for the continuous improvement of water environment quality in China. An in-depth understanding of pipeline sediments and their deposition mechanism is essential for water pollution control. The formation and characteristics of pipeline sediments, the main components of microorganisms or extracellular polymeric substance (EPS), and the effects of related properties on the anti-scouring characteristics of sediments were reviewed. The results showed that the sediments in drainage pipelines were mainly formed by the sedimentation of solid particles carried by sewage, and mainly included three types, i.e. bottom coarse-grained sediments, organic layer and biofilm. Because the sediments were rich in microorganisms and could secrete EPS, the viscosity of EPS could significantly increase the scour resistance of pipeline sediments. By controlling or degrading the polysaccharide component in the EPS of the sediments, the erosion resistance of the sediments could be reduced, which was expected to provide a new idea for controlling the sedimentation of the pipelines. At present, the domestic and foreign methods for controlling the sedimentation of pipelines were mainly through offline and online hydraulic scouring or mechanical dredging. The future research direction should focus on systematically studying the erosion resistance characteristics and influencing factors of sediments in the real drainage pipe network, and then propose more effective control technology methods.

     

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