Our huge investment will allow a greater volume of sewage to be treated to the highest standard, while also protecting the environment by improving the quality of treated wastewater released into the Severn Estuary.
Why is this expansion needed?
Bristol’s water recycling centre treats sewage and wastewater from the city and the surrounding area, but with the city’s population projected to increase significantly in the next 20 years, further capacity is needed to meet these demands.
This increased treatment capacity will also play a role in reducing the automatic operation of storm overflows when rapidly increasing flows caused by sudden heavy storms can overwhelm the sewer system.
An essential component of the city’s vision to put good social and environmental outcomes at the core of sustainable economic growth, expanding the existing site is also likely to offer further benefits to the city through associated economic opportunities as its construction begins.
Overall, the expansion project is expected to take five years to complete.
The beginning of construction
The project to expand the water recycling centre at Avonmouth got underway in January 2024, with the opening six months concentrating on contractors Envolve preparing the site of the expansion for the installation of site infrastructure.
Despite 2024 being one of the wettest winters on record, thousands of tonnes of earth were excavated and moved, and materials were laid down at the expansion area.
More than 3,700 concrete piles were driven into the ground as foundations for the new equipment - such as the treatment tanks and pipework - were built.
If laid end to end, these piles would stretch 74 kilometres – or from the Avonmouth site to the outskirts of Hereford in the north, Salisbury in the east, Port Talbot in the west or into Dorset in the south.
Watch this video to see the expansion project’s first six months of progress.
Latest progress
Through the second half of 2024, significant progress was made to get much of the site’s infrastructure in place.
More than 25,000 tonnes – or in excess of 10,500 cubic metres – of concrete has been used at the expansion area, allowing progress on the multiple structures that are being constructed.
This included a record-breaking concrete pour in the autumn, which saw more than 3,600 tonnes (1,509 cubic metres) laid across an 18-hour period – the largest continuous Wessex Water concrete pour to date – beating the previous record set at our £50 million refurbishment of Durleigh Water Treatment Centre in Somerset.
In excess of £260,000 worth of concrete, within 200 loads and using three pumps, was part of what providers Wrights estimated was the largest continuous pour in Bristol.
More than 3,363 tonnes of reinforcement was also put in place as structures including the sequential batch reactors – part of the enhanced treatment process – started to take shape.
In total, four such reactors – each measuring 2,500 square metres and with external walls standing 8.5 metres high – are being built. Our team are simultaneously working on three reactors with a mixture of base slabs and walls.
We also started the first of four primary settlement tank structures, each with a diameter of 42 metres.
Watch this video to see how the expansion project has progressed in recent months.
How the work will impact traffic
As set out in the traffic management plans within the planning application, all large construction traffic will route to the A403 via Kings Weston Lane or Kings Weston Lane and Merebank Road, avoiding Lawrence Weston Village.
A temporary access and exit onto Kings Weston Lane from the expansion site has been established.
What else are we doing?
As part of our construction work, we will be clearing vegetation and installing temporary fencing to protect sensitive environmental areas and buried services. Checks for nesting birds will be carried out by our ecologists before vegetation is removed.
Our public consultation process underlined that many local people wanted to see more information about the local archaeology around the water recycling centre and proposed expansion site.
We have already carried out substantial investigations into the local heritage, particularly the Mere Bank Scheduled Monument, with Historic England and Bristol City Council’s archaeologist advising on the design and survey requirements throughout.
Read more about the Mere Bank Scheduled Monument Investigations.
During our consultations, you also made clear your support for our proposals to revitalise and improve footpaths adjacent to the water recycling centre.
The opening stages of that work will take place in the early part of 2025 when we’re diverting two local rights of way (BCC/18/10 and BCC/5/10) while we continue the expansion.
The diverted footpath will now join the existing right-of-way network, allowing users a safer, more pleasant and accessible route to view the newly established ditch next to the site, which provides a habitat for reed bunting birds.
Working with the community
With support from the Community Liaison Group and research with local stakeholders, a new grant fund - the Avonmouth Area Community Fund - was announced by our Wessex Water Foundation and opened in July 2024.
The fund, which will be open for three years, aims to improve the lives of the people in the Avonmouth and Lawrence Weston ward, including Shirehampton.
Around £35,000 was awarded to seven causes in the area in the first round of funding, announced in October 2024.
Members of our project and contactor team also completed a volunteering day at Avonmouth Community Centre this summer, carrying out gardening and clearance work.
They also completed a volunteering day at Bristol North West Foodbank’s hub at St. Andrew's Church in Avonmouth prior to Christmas 2024.
How to stay informed
As well as updating this page, we’re keeping customers and stakeholders informed via a project newsletter.
Subscribe to the newsletter to receive updates about the expansion and other information every few months.
If you have any further questions about this scheme, please email avonmouth.scheme@wessexwater.co.uk.