Water recycling

We treat 898 million litres of sewage from 2.9 million customers every day before it is safely released back into the environment.

What is water recycling?

Water recycling is the process of treating wastewater to make sure it is safe to release into local waterways. By treating wastewater, we ensure harmful bacteria and organisms are removed which helps to protect habitats and wildlife across the region.

Why is water recycling important?

We rely on our natural environment to provide us with the water we need. So, we must monitor our water use and ensure that we treat and recycle our water so it can be returned safely back into the environment for it to continue its course through the water cycle.

The continued growth of population and climate change is increasing water supply demand so, to ease that pressure and ensure that enough water is being treated and recycled, we are continuing to invest in reducing leaks across our network and helping customers to improve their water efficiency.

River surrounded by trees and grass on a sunny day

What is the water recycling process?

Whenever a toilet is flushed or liquid is poured down the drain, sewage is produced. Other sewage we treat includes rainwater from roads, roofs and gardens as well as industrial effluent. Our sewerage network carries this sewage to our water recycling centres where the water recycling process begins.

When sewage arrives at our water recycling centres, debris, rags and large objects are removed using screens. It then flows into tanks where the solids that couldn’t be removed during the screening process sink to the bottom and are removed as sludge.

Next, the sewage is treated biologically by passing it through stone or plastic filters which have a layer of bacteria on them. These bacteria feed off the waste, helping to clean the water. As the wastewater comes through these filters, it enters settlement tanks and humus sludge is produced. These are the bodies of the bacteria as they die which are removed through this final settlement stage.

The cleaned wastewater (effluent) then leaves our water recycling centres and flows into local rivers or the sea.

Treated sludge, also known as biosolids, is a by-product of our treatment process. We treat sludge in anaerobic digesters (a process through which bacteria break down organic matter) to produce agricultural fertiliser and renewable energy.