A field experiment to evaluate the cleaning performance of sewer flushing on non-uniform sediment deposits

SewerSedFoam: A Model for Free Surface Flow, Sediment Transport, and Deposited Bed Morphology in Sewers

“…The selection of an appropriate case study to validate SSF under erosion conditions proved to be significantly more challenging than in the deposition case. A number of studies detail different erosion scenarios in sewers [18,38,39], but these studies are mainly based on longer stretches of sewers in the field; which limits the quantity and granularity of any of data that is collected. All the case studies have some critical data limitations for flow and/or sediment characteristics, so this section is focused on analyzing the functionality of SSF for erosion scenarios rather than a detailed validation, for which there is insufficient data in the literature at the time of this analysis.…”

“…All the case studies have some critical data limitations for flow and/or sediment characteristics, so this section is focused on analyzing the functionality of SSF for erosion scenarios rather than a detailed validation, for which there is insufficient data in the literature at the time of this analysis. Data from the case study of a sewer sediment erosion event in Paris, France induced by flushing through a hydraulic gate is used in the SSF erosion analysis [38]. This case study is a large trunk sewer that is over 3 m in height, consisting of a roughly circular upper two thirds, a roughly rectangular channel (or cunette) in the bottom third, and side walkways along the top of the rectangular channel.…”

“…Shahsavari et al [38] monitored five locations across 1100 m of the trunk sewer in Paris. A total of 10 m of this sewer is modelled in SSF based on a location 5 m after the hydraulic flushing gate, S +5 in Shahsavari et al [38], which has little to no pipe slope. Further, the area of interest in this case study is the lower rectangular channel of the sewer where the deposition and erosion of sediment occur.…”

“…Besides these changes, the other boundary conditions are similar to the previous deposition case. A constant average flow velocity was calculated for the inlet boundary condition based on the available parameters, flow height and volumetric flow rate, and the cross-sectional area of the sewer to represent the peak flow velocity experienced during the flush [38]. However, this value does not consider the impacts of the sewer geometry which are likely to be significant.…”

“…Two sediment fractions, Type A and Type E, were used in the Paris trunk sewer SSF model. Organic Type C sediment is not included in this analysis due to the low measured proportion of organic sediments deposited in the sewer [38]. The measured bed sediment diameter and density measurements from Shahsavari et al [38] were used to determine the Type A and E sediment characteristics (Table 3).…”