A major Scottish Water operation in Edinburgh has provided a rare glimpse of a colossal piece of machinery vital to the city's wastewater infrastructure. The publicly-owned utility has successfully installed a nine-tonne screw pump into a deep underground chamber as part of a £5 million upgrade to the McDonald Road Wastewater Pumping Station.

The pumping station, which has been in operation for over 50 years, utilises enormous Archimedean screw pumps to move millions of litres of wastewater across the capital. To ensure the continued efficiency and reliability of Edinburgh's sewer network, the site is undergoing significant refurbishment.

Dramatic footage captured the complex operation, showing a crane lowering the 14.4-metre-long screw pump into the ground near Broughton Primary School. This newly installed pump replaces the original, which was removed in October 2024.

The newly installed screw pump is known as the "foul" or "duty" screw and operates daily to move wastewater and collect drainage from the Canonmills and Broughton areas of the city. It transfers this to a large sewer, where gravity then takes over, carrying the wastewater to Scotland's largest treatment plant at Seafield. The pump is capable of processing an impressive 1,800 litres of water per second.

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Rob Mustard, Scottish Water's Director of Capital Investment, highlighted the significance of the project, stating: “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.”

He also acknowledged the complexity of the operation, adding: “Extracting and installing assets of this size is challenging work, and it requires a good deal of forward planning and co-ordination to be undertaken safely... 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, commented on the unique opportunity to witness such infrastructure work: “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 next to the larger "storm screw," which operates during periods of heavy rainfall. The original storm screw was removed in December 2023 and replaced with a new one in April 2024. The overall refurbishment project is being delivered in partnership with Morrison Water Services.