Wessex Water achieves UK first with CIPP pressure main lining in active sewage works


South-west England utility company Wessex Water has become the first company in the UK to deliver a pressure main liner to the new international standard for cured-in-place pipes (CIPP) under pressure in an active sewage treatment works.

Christchurch STW
Wessex Water’s Christchurch STW

The liner was installed inside a defective rising main at Christchurch STW near Bournemouth, when it became apparent that an easy fix was not possible due to the close proximity of a storm settlement tank.

Paul Musselwhite, Wessex Water’s multi-functional general foreman, explained: “Our R&M waste department came up with a solution to overland the defective pumping main to keep the local network in operation. This also allowed time for the in-house rehab team to design one of the first pressurised liners to be installed.”

Critical sewers engineer Nathan Hand added: “What was different here was putting a liner in a pressure main, so it had to be able to handle internal pressures from the pumps.”

To insert the liner in a pressure main, the design and materials had to be very different, with glass fibre woven into the felt to strengthen it and using a special blend of resin.

“Both excavations were completed in very challenging ground conditions, and we worked in close partnership with the main treatment guys and local scientists,” said Paul Musselwhite.

To see a video of the scheme click here.