Footage shot during a major Scottish Water operation in Edinburgh has provided a rare glimpse of an underground giant vital in keeping the city’s wastewater network flowing.
‘Foul’ screw pump at a glance
- Weighs in at nine tonnes
- 14.4-metres long
- Made of stainless steel
- Capable of processing 1,800 litres of water/second
The publicly owned utility has installed a nine-tonne screw pump into a deep underground chamber as part of a £5 million investment in McDonald Road Wastewater Pumping Station.
The pumping station uses enormous Archimedean screw pumps to move millions of litres of wastewater across the capital. It has been in operation for over 50 years, so the site is undergoing major refurbishment to ensure the continued efficiency and reliability of the city’s sewer network,
The image shows a crane lowering the 14.4-metre-long screw pump, which is capable of processing 1,800 litres of water per second, into the ground outside a local school.
The newly installed screw pump replaces the original which was removed from the ground in October 2024. It is one of two screw pumps below ground in the road.
Known as the “foul”, or “duty” screw, it is in operation every day to move wastewater and collect drainage from the Canonmills and Broughton areas of the city, transferring it to a large sewer.
Gravity then takes over and the wastewater runs along the sewer to Scotland’s largest wastewater treatment works at Seafield for treatment.
Rob Mustard, Scottish Water’s Director of Capital Investment said: “The refurbishment of McDonald Road Pumping Station represents a significant investment in Edinburgh’s waste water network, supporting our goals of service excellence and delivering improvements for the benefit of the environment and customers for years to come.”
Extracting and installing assets of this size is challenging work, and requires a good deal of forward planning and co-ordination to be undertaken safely.
He added: “The screw pump installed at McDonald Road Pumping Station is just one of many impressive and vital underground assets serving communities across Scotland, most of which people will rarely see. This was a major operation and our dedicated teams are to be congratulated for carrying out the challenging work safely.”
William Moore, Scottish Water’s project manager for the operation, added: “It’s not every day that people get to see the hidden giants that keep Scotland’s waste and water cycle running, so it’s been fantastic to be able to share footage of the extraction and installation of these colossal screw pumps during the refurbishment with the community.”
The foul screw is located adjacent to the larger “storm screw”, which operates under storm conditions. The original storm screw was removed in December 2023 and replaced with a new one in April 2024.
The project is being delivered alongside delivery partner, Morrison Water Services.
