The situation
Through CCTV investigation, we have identified infiltration into the sewers in Budleigh Salterton. Infiltration is when surface or groundwater enters the sewers in places it’s not meant to, such as through manhole covers or pipes in need of repair. This means that a lot more water enters the sewers and increases the risk of activating our storm overflows.
Through repairing the pipes, we can reduce the volume of water travelling through the network, which will help reduce the risk of spills and pollutions from these assets.
The plan for Budleigh Salterton
In September, work will begin to start reducing the amount of water that is entering the sewer network. The work will be carried out in stages and is planned to continue throughout the autumn.
We’re planning to repair the sewers with the very latest lining technology, which will reduce the number of excavations needed as the repairs all happen inside the pipes.
Here's a bit more about how the lining process works:
1. Preparation
Before lining starts, the sewer is diverted using an overland pipe. The empty section is then cleaned and inspected with a CCTV camera. Pipes connecting into the sewer are accurately mapped so that the connections can be re-opened once the sewer has been lined.
2. Inserting the liner
A sliding foil is pulled through the pipe before the liner to reduce the amount of friction between the liner and the sewer. Then the liner sock is inserted using a 5-tonne winch. Air is pumped into the liner to expand it.
3. Curing
The liner is infused with polyester resin which is then dried by passing a UV light through it. The light reacts with the resin, curing it in place. Depending on the size of the pipe, the robot can dry between 0.5m and 1.5m per minute.
4. Reopening the connecting sewers
Once the liner is cured, flow through the sewer is restored. Then, the connecting sewers can be reopened. Our teams use a robot to do that too. The position of the connections are logged in the robots computer, and the robot cuts holes in the liner at exactly the right location.
5. The sewer is repaired
This method of repairing sewers means that the work can be completed much faster and with less disruption than traditional ‘open cut’ excavation. On average, 100 metres of pipe with a 225mm diameter can be repaired in just 1 day. And a liner like this is expected to last for decades.
What will we see?
In some areas, we'll still have to use more traditional excavation techniques due to the age and condition of the sewer. You’ll see diggers and our teams and contractors working on the roads before they put the area back to how they found it.
To carry out these works effectively it is likely that some tankering and over-pumping will be needed, this will allow the upgrade to be done without disrupting the existing system.
Whilst carrying out these works to tackle the identified infiltration, we will continue to survey the sewers further upstream for further infiltration.
Please note that some traffic management will be required to keep our teams safe whilst these works are carried out to improve the sewer network. Updates will be provided on this webpage.