Floating wetlands for preliminary water treatment

Overview

The Witches Oak scheme in Derbyshire was undertaken by Mott MacDonald Bentley on behalf on Severn Trent Water.

The project focused on providing preliminary and entirely biological water treatment using 31 floating wetlands to bring an abandoned water resource back into use.

Combined with upgrading of existing structures, the scheme helped improve the resilience of drinking water supplies during future droughts.

It was the first time in the UK that wetlands were used for operational water pre-treatment on this scale.

Theoretical studies show that, on average, floating wetlands could remove 40% to 60% of total nitrogen (ammonia, organic and oxidised nitrogen) and total suspended solids (particles larger than two microns).

This approach considerably reduces the amount of energy and chemicals needed for the subsequent traditional treatment process.

Join Leah Southan, environmental specialist at Mott MacDonald to find out more about the Witches Oak scheme and how natural processes can be used to pre-treat water.

Programme