To meet the Urban Waste Water Treatment Directive (UWWTD)regulations the UK Regulator, the Environment Agency, requires continuous monitoring of the quantity of effluent discharged from works with an average dry weather flow (DWF) of 50m3/day or greater. Most works discharge through a channel or partially filled pipe. This poses a challenge to current methods of open channel flow measurement.
This project sponsored by the UK Water Industry Research (UKWIR) looks at 4 measurement technologies installed on a small treatment works to assess their capability of monitoring such discharges to the Agency's requirements. Yorkshire Water is monitoring the 4 technologies with accuracy checks being carried out in-situ using a volumetric drop tank method.
A second part of this project is looking at the maintenance requirements of a narrow angle V-notch weir (the only gauging structure covered by British Standards able to measure these low flows) in order to achieve the required performance. This is being carried out on a purpose built rig, situated on a Thames Water site.