Author(s): R. M. Ashley; M. A. Verbanck
Abstract: Knowledge about the behaviour and effects of solids in sewer systems has advanced considerably in the past decade, with new guidance for the control of sewer solids and associated pollutants emerging to protect the environment and for the better operation of wastewater systems. Sediment transport in sewers, whilst being controlled by the same physical processes as prevail in natural waters, is affected much more by the limited physical scale. Transport is influenced by the cross-sectional shape in particular and limited sediment supply, with the effects of spatial and temporal variations in hydraulic conditions being particularly significant in sewers. This paper describes new theories that are providing the means to estimate when and by how much sediment beds will erode, how the particles and released pollutants will be transported, and as a consequence their potential impact on downstream systems.