Experimental study of the velocity and suspended solids distribution in wastewater system.

Frédérique Larrarte, Jean Jacques Randrianarimanana, Laurent Lebouc, Emilie Szturyz

Thursday 2 july 2015

8:30 - 8:45h at South America (level 0)

Themes: (T) Water engineering, (ST) Experimental facilities and instrumentation

Parallel session: 10C. Engineering - Industrial

A good management of wastewater systems is essential for technical and economic reasons to achieve the good ecological status of aquatic environments. It requires a better understanding of pollutant loads discharged at both event and annual scales, to improve the operation and management of urban sewer systems, and also to minimize pollution discharged into receiving waters. Precise knowledge of the pollutant fluxes requires a better assessment of both velocity and suspended matter fields. This paper presents an experimental study in order to evaluate the influence of a singularity, in this case a confluence, and to enhance knowledge on the total suspended solids and velocity profiles in sewers, for assessing the representativeness of continuous measurements of water discharge and pollutant loads discharged. The experimental site is formed by the confluence of two channels. Three measurement points were selected: upstream of the confluence; the branch of the confluence; and downstream of the confluence. The flow rate and the water level are constantly monitored by the flowmeters to acquire chronic over a long period on the three measurement points. The wastewater quality is also constantly monitored by turbidity, conductivity and pH measurement. The spatial distribution of both velocity and total suspended solids are investigated using two 2D dimensional samplers called Hydre, for a range of hydraulic situations. The data results of Hydre are used to validate the data allowed by the continuous measurement sensors. The results will contribute to develop a methodology for designing the instrumentation of a sewer section, including site qualification, the aim of the MENTOR project