Anglian extends sewer capacity to avoid overflows

Anglian has invested £100 million to grow the capacity of its sewer networks with storm water storage to capture surface runoff and ease pressures on treatment centres during heavy rainfall.

The additional tanks can capture and redirect more than 72.5 million litres of rainwater to prevent treatment works and sewer systems being overwhelmed and storm water being released into watercourses through overflows.

The work was undertaken as part of the company’s Get River Positive programme, which it launched together with Severn Trent in March and includes five pledges to revive waterways, one of them being to ensure storm overflows and sewage treatment works will not harm rivers.

Installing new storm tanks means larger volumes of rainwater can be stored to prevent the reliance on combined sewer overflows (CSOs). The water held in tanks will be released through the network’s recycling process system at a controlled rate the treatment works can accommodate before being returned to watercourses.

Carly Leonard, head of environmental strategy for Anglian Water, said the recent dry summer has been a contributing factor to flooding because the ground remains harder than usual so surface water takes longer to drain away.

“We need resilient infrastructure that can rise to the challenge and help us protect the environment at the same time. Being able to store excess water on our sites means that less ends up in our rivers, seas and some of the unique habitats in our region.”

The company has more than 1,500 combined sewer overflows across its network that it is adding event duration monitors to. This is a sector-wide obligation to install EDMs at all CSOs by the end of 2023.

Government has proposed targets to minimise the risk of harm from CSOs upon watercourses by 2050, starting with the overflows that cause greater harm and those close to bathing waters.