Case Study: Realtime Monitoring Cuts Pollution Risk at Scottish Water Site
New NRV (Image source: Xylem Inc.)
Planned maintenance
Scottish Water and Xylem were carrying out planned maintenance at St Nicholas Sewage Pumping Station (SPS), a large, terminal site in St Andrews, which receives flows from five upstream stations. The scope included replacing an inlet gate valve and non-return valve (NRV), along with pump impellers and wear plates.
During the works, engineers found the isolation valve was not sealing, allowing pressure to backflow. This meant the NRV could not be replaced without fully draining the line back into the wet well. Attempts to reseal the flanges failed as the pressure had damaged the gasket beyond repair.
Tankering was not viable due to high inflows exceeding available capacity, leaving the station reliant on its standby pump. Without a quick solution, costly and disruptive over-pumping would have been required – with any failures potentially impacting the famous St Andrews golf course.
The team instead developed a solution to restrict flows from the five upstream stations using their available storage, while the rising main was drained and the NRV replaced. This approach required real-time monitoring of the five stations. Crucially, two of the assets were equipped with Xylem’s Avensor monitoring system, providing live data on levels and asset health.
Data-driven insights
Avensor is a digital service that provides alerts and data-driven insights from a device connected to pumping stations or other assets. Once a modem is installed, Avensor collects and analyses data to give a complete overview of all connected operations, including trends and alerts, via the web and a mobile app. Insights from Avensor allowed engineers to remotely monitor conditions and attend sites only when necessary to pump water in a controlled manner. The remaining three stations were monitored through periodic site checks. With this intelligence in place, St Nicholas SPS was safely shut down, the rising main fully drained and the NRV replaced.
Throughout the operation, teams worked collaboratively, adapting plans in real-time. As a result, Scottish Water asked Xylem to quote for additional work onsite.
Results
- St Nicholas SPS returned to full operational status without the need for over-pumping
- Significant cost and time savings achieved by avoiding additional mitigation measures
- Environmental risk reduced, with controlled flows preventing pollution events
- Minimal disruption to Scottish Water operations despite the complexity of the site
- Demonstrated value of Avensor, providing real-time intelligence at a critical moment.
This project highlights how Xylem’s engineering expertise, rapid problem solving and digital monitoring technology can resolve unexpected issues on complex assets. It also demonstrates the wider value of Avensor, enabling operators to make informed, timely decisions that mitigate pollution risk and deliver better outcomes.
Mike Kelly, Scottish Water’s wastewater networks team leader, said: “This was a complex job on a busy terminal pumping station. Having live information available allowed our team to manage incoming flows safely, respond quickly and keep the wider environment protected while the work was completed. Working closely with Xylem, we were able to restore the station to full operation, avoiding the cost and disruption associated with temporary over-pumping.”
Source: Xylem Inc.
