Monitoring accumulation sediment characteristics in full scale sewer physical model with urban wastewater

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

“…Field observations indicate that the stabilization of newly deposited sediment beds in sewers occurs in the scale of a few hours [2]. Further, pilot sewer investigations have shown that sediment deposition can occur for several days under low flow conditions even when the flow velocity increases after some initial deposition [35]. These complex stabilization processes have been incorporated using a somewhat simplistic method in SSF, whereby φ D is increased from a default value of one based on increasing applied shear stress from flow velocity until a user set maximum bed height is achieved:…”

“…The case study for sediment deposition is based on data published in Regueiro-Picallo et al [35] from a pilot plant in A Coruña Wastewater Treatment Plant (WWTP) in A Coruña, Spain. The pilot plant consists of two 8 m long plastic sewers, one circular and the other egg-shaped, with an adjustable slope.…”

“…Screened wastewater from the WWTP was made to flow through both sewers while measuring deposited bed height and flow characteristics. Sediment deposition was induced in the experiments by setting the flow height at the outlet of the pipes to 100 mm using a gate [35]. Two experiments using the circular pipe while it had a 0.2% slope, i.e., Scenarios 6 and 7 from Regueiro-Picallo et al [35], are modelled in this validation study.…”

“…Lastly, the timestep of the simulation and the mesh refinement were balanced to achieve a maximum Courant number of 0.8. The published velocity results in Regueiro-Picallo et al [35] only include one data point along the pilot sewer for Scenario 6. However, Scenarios 6 and 7 have very similar flow characteristics and the results are likely to be very similar for both.…”

“…The average bed sediment density for both scenarios was 1460 kg/m 3 . The effect of the mixing on the characteristics of the overall influent sediment appears to have been more complicated with a reduction in diameter of volatile solids and increase in diameter of non-volatile solids [35].…”