Melbourne Water Flow Meter Investigation

Client: Melbourne Water
Date: September 2011
Challenge: GHD Undertook an audit of large (e.g. up to 3,000 Megalitres per day) of open channel and closed conduit meters within the Wastewater Treatment Plant to improve understanding of flow measurement across the site, to quantify the accuracy of flow measurement and the influence this is having on distribution of wastewater volumes within the plant.

Description

An innovative methodology was developed and implemented to assess the magnitude and influence that measured flows have on the determined distribution of wastewater volumes. The methodology involved the following steps:

• Undertook a site inspection of meters to assess their degree of compliance with reference conditions. Site photographs, site notes, ‘as constructed’ drawings, manufactures’ specifications, maintenance procedures are examples of the information that was used to assess capability/performance and the different errors associated with a particular meter and its installation
• Undertook an analysis of the recorded volumes of water measured by the meters used in wastewater flow balancing for the site to establish a statistical estimate of the bias error of a particular installation
• Established the statistical uncertainties of the imbalances between meters taking into account previously estimates of bias and random errors

The Outcome

The findings of the flow meter audit were used to determine the statistical uncertainty of water balancing by quantification of errors associated with flow monitoring. The benefits of the approach were its cost effectiveness, timeliness, scientifically sound and defensible.

For more information, please contact:

Edgar Johnson
T 61 8 8111 6770