With UK water companies facing unprecedented challenges in terms of aging infrastructure, leakage, pollution, drought-related issues and financial constraints, the need to adopt cost-effective digital solutions is now seen as crucial.
A commitment to significant investment in new and improved monitoring in order to comply with changing legislation, has brought the subject of ‘event duration monitoring’ to the fore.
According to the latest Environmental Performance Assessment by the Environment Agency, four of the nine water and sewerage companies operating in England that provide clean water and wastewater services were found to be significantly below environmental performance targets. This only fuels the call for urgent adoption of innovative and reliable digital EDM technology such as clamp-on ultrasonic flow measurement, in order to ensure environmental protection and regulatory compliance.
What is event duration monitoring?
In relation to flow measurement, an ‘event’ is determined as an ‘adverse weather event’ – usually a storm, which has the effect of increasing flow through a Sewage Treatment Works (STW).
All STWs have an upper limit of flow that is permissible to treat, which is known as Flow to Full Treatment (FFT) or Pass Forward Flow (PFF). If during a storm event the flow within an STW exceeds this limit, it is authorised to overflow into a storm management system or even directly discharge into a river or the sea.
There are other factors that may influence an STW’s decision to discharge to a storm management system or river before the maximum limit is reached. There could be other unrelated reasons such as population growth placing excess demand on the STW’s original flow capacities, which risks more frequent breaches of their approved Flow to Full Treatment.
Event duration monitoring allows water utility providers to keep a reliable record of all instances of overflow spilling. Combined with other data including weather conditions and the volume of flow going forward to treatment at the time of the event, this provides regulatory evidence of a storm event being within the site’s permit condition. In the event of it being found to be outside the permit condition, the water utility provider has the benefit of enhanced data in order to make changes to the site and avoid further untimely spills.
Environment Agency measures designed to better monitor Flow to Full Treatment, include the requirement for UK water companies to install EDM monitoring by 2025. And the Government’s additional planned measures are intended to make sure that outside of storm events, STWs do not unduly rely on the use of storm overflows.
Accurate and reliable non-contact event duration monitoring
Clamp-on ultrasonic flow measurement is able to deliver a non-invasive and cost-effective event duration monitoring solution for closed conduit pipes. This technology provides real-time data on the flow rate of storm outflows, which can be used to monitor the amount of water flowing out of a particular area during a storm event. One of the key advantages of clamp-on ultrasonic flow measurement is that it is completely non-invasive. There is no need to cut or modify the pipe, eliminating unnecessary downtime – installation is simple and cost-effective. And because there is no contact with the fluid being measured, there is absolutely no risk of contamination.
Ultrasonic clamp-on flowmeters have a simple design, comprising clamp-on transducers and an electronic converter that calculates and transmits volumetric flow rates. They have no moving parts and never touch the internal fluid, meaning that the need for time-consuming maintenance is greatly reduced, if not eliminated altogether.
Thanks to powerful clamp-on transducers and sophisticated Advanced Meter Verification software, ultrasonic flowmeters from FLEXIM are able to deliver accurate, drift-free and highly repeatable flow measurement data with unparalleled levels of confidence in meter health and performance. They are also easy to calibrate and can be specified with IP68 waterproof protection rating for added peace of mind in flooded conditions.
