Figure 35 - uploaded by Karsten A Sedmera
Content may be subject to copyright.
Source publication
The current study has two objectives. The first is to evaluate Roger Kilgore’s proposed procedure, which
requires conducting some of the same types of tests that were run in the previous study. The new tests
conducted include a wider range of parameters, such as greater plunge-height ratios and steeper pipe
slopes. Previous research was limited in...
Citations
... Flows containing surcharges below this ratio are completely mixed in a vortex whilst surcharges above present two distinct flow regimes in the same flow (Guymer et al., 2005). More recent studies have utilized submerged jet theory where the jet flow starts expanding as it proceeds towards the outlet pipe due to the through-flowing water from the inlet pipe accelerating the entrained water in the manhole causing surplus discharge to be lost (Beg et al., 2017;Kerenyi et al., 2007;Mark and Ilesanmi-Jimoh, 2016;Stovin et al., 2008;Stovin et al., 2010). Beg et al. (2017) proposed that as the jet flow reaches the entrance of the outlet pipe in circular manholes it expands and a portion hits the manhole wall at the top of the outlet, proceeding vertically upward into a dead zone at the top of the manhole (Sokáč and Velísková, 2021). ...
The transport of microplastics within urban water systems remains poorly understood, with little prior research
on their behaviour within manhole configurations. This study represents the first to measure and model the
transport dynamics of microplastics within circular and square manholes under different hydraulic scenarios. The
transport and fate of polyethylene (PE) was quantified and compared to solutes (Rhodamine WT dye) using
energy losses, residence time distributions (RTDs), and mixing models within surcharging and overflowing
manholes. The bulk mass of solute and PE concentrations followed similar flow paths across all conditions except
for 17.3 ± 7.9 % of PE mass that was immobilized in a dead zone above the inlet pipe for manholes with a
surcharge to pipe diameter ratio ≥2. Consequently, these microplastics only exit after a significant change in
hydraulic regime occurs, causing microplastics to be at risk of being contaminated over a prolonged duration. No
significant mixing differences for PE and solutes were found between manhole geometries. The deconvolution
method outperformed the ADZ model with goodness of fit (Rt^2) values of 0.99 (0.60) and 1.00 (0.89) for PE and
solute mixing, respectively. This establishes the deconvolution method as the most accurate and appropriate
model to accurately predict microplastic mixing in manholes and urban drainage systems.
