Net Zero Hub


Severn Trent is leading the water sector in reducing greenhouse gases by building the
world's first net zero wastewater treatment hub and sharing their learnings with others.
 

Strongford

Watch our exciting showcase about how we’re building the world’s first Net Zero Hub for wastewater treatment. This hub will use cutting-edge technologies to reduce greenhouse gas emissions and create a blueprint for other companies to follow.

The video showcases the innovative technologies used at the Net Zero Hub, the lessons learned throughout the process and our future plans.

Why Severn Trent are taking a lead

A few years ago, we decided to make our Triple Carbon Pledge, that was made up of three component parts.

As part of our plans to remove and reduce the most potent greenhouse gases from our wastewater treatment processes, we have been running our Net Zero Hub at our Strongford  (Staffordshire) wastewater treatment works that serves over 400,000 customers.

In our first year we have made strong progress.

We have formed a partnership with Aarhus Vand in Denmark and Melbourne Water in Australia. We're also collaborating with all the UK and Ireland water companies through the Ofwat Innovation Fund. As a founding member of the World Water Innovation Forum, we collaborate with global companies, sharing our expertise and learning from challenges to improve our practices.

We are bringing several technologies together to drive down our carbon footprint, and that is going to create a blueprint for us and the sector for the next five years. By doing this we will also gain an insight into how we're going to apply the technologies across all our patch. We have invested £40 million, supported by £10 million from the Ofwat Innovation Fund, in this single transformational net zero hub site at Strongford.

Innovation in action: case studies

An overview of past and future projects driving forward progress towards meeting customer commitments and sustainability goals.

There is a significant amount of cellulose in sewage (originating from toilet paper - toilet paper is approximately 80% cellulose). In the ST region alone, we receive approximately 100,000 tonnes of cellulose per year.

Cirtec, a Dutch company, have developed a process where the cellulose fibres can be recovered. This recovered cellulose can be used as a structural material to substitute virgin cellulose - it has been used in asphalt, concrete and other building materials as well as biocomposite materials. It can also be used as a feedstock for chemicals including acetic acid and polymers.

Life cycle analysis has estimated that cellulose recovery can improve the of a sewage treatment works and help to reduce its carbon footprint by up to 15%.
 

Ammonia is present in sewage and needs to be removed as it is toxic to the aquatic environment. 

Ammonia is removed in a biological ‘secondary’ treatment process, which, in a large wastewater treatment works, is carried out very effectively in a process known as an Activated Sludge Plant (ASP).  These large aerated open tanks convert most of the ammonia to nitrate and nitrogen gas, but a small amount of the ammonia is converted to, and emitted from, the tank as nitrous oxide.

Nitrous oxide is a very potent greenhouse gas (273 times as potent as carbon dioxide) and so not much of it is needed to have a large impact on the carbon footprint of a wastewater treatment plant.  The emission of nitrous oxide from ASPs may be responsible for up to half of the total carbon footprint of a site.

Severn Trent in collaboration with Suez have developed a world first passive photocatalytic cover (called ‘Actilayer’) that covers the ASP tanks and converts the nitrous oxide to harmless nitrogen and oxygen gas as it passes through the permeable cover.
 

And there's more

You can read more of our exciting case studies about projects across our region to deliver outcomes our customers care about, drive positive change, and work hand-in-hand with nature.

View our showcase

What we've learnt so far

Our experience building the world's first net zero wastewater treatment hub highlights the importance of measurement, strong partnerships, collaboration, and knowledge sharing.

Get in touch

If you have any questions or would like to get involved, email our Open Innovation inbox.

Email us