Underground giant lowered deep into Edinburgh chamber

03 April 2025

Going deeper underground

A rare glimpse at one of the underground giants keeping Edinburgh's waste water network flowing

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 waste water network flowing.

The publicly-owned utility this week installed a nine-tonne screw pump into a deep underground chamber as part of a £5 million investment in McDonald Road Waste Water Pumping Station.

The pumping station uses enormous Archimedean screw pumps to move millions of litres of waste water across the capital. It has been in operation for over 50 years and to ensure the continued efficiency and reliability of the city’s sewer network, the site is undergoing major refurbishment.

The incredible footage shot 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 Broughton Primary School.

'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

McDonald Road Pumping Station

The screw pump is shown securely fastened in place on a wagon

The new screw pump arrives at McDonald Road in Edinburgh

The screw pump is shown in the air as it is being transferred to site

Teams carefully hoist the metal giant into the air

The screw pump is shown being hoisted into position by a large crane

A crane is used to position the screw pump in place

The screw pump is shown being lowered into place by a crane during the major operation

The pump is inserted into the deep underground chamber

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 at McDonald Road. Known as the “foul”, or “duty” screw, it is in operation every day to move waste water and collect drainage from the Canonmills and Broughton areas of the city, transferring it to a large sewer. Gravity then takes over and the waste water runs along the sewer to Scotland's largest waste water treatment works at Seafield for treatment.

The old foul screw pump is shown having been removed from the ground at McDonald Road Pumping Station

The old pump screw, which was removed in October 2024

A giant screw pump is shown arriving at McDonald Road on the back of a wagon

The replacement screw is ready to get to work

“It's not every day that people get to see the hidden giants that keep Scotland's waste water cycle running”
William Moore
Scottish Water's project manager for the operation

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.

Rob 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 said:

“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.