A new storage reservoir and pumping station have been built next to the existing works, to store an additional 40 million litres of treated water to secure supplies for more than a million homes and businesses in the Cambridgeshire, Bedfordshire and Milton Keynes area.
The storage reservoir is thought to be the largest pre-cast storage reservoir in Europe, possibly the world, requiring 6,000 cubic metres of concrete.
However, Anglian Water and alliance partner JN Bentley were able to halve the embodied carbon and find £20 million in efficiency savings during the project.
Anglian Water chief executive Peter Simpson said: “We were thrilled the Duke of Edinburgh has honoured Grafham Water with a visit – not just once, but on two landmark occasions in the site’s history.
“Grafham Water was a trailblazing project when it was first conceived in the Sixties. The Duke called it ‘far-sighted’ at that time, and we continue to uphold that forward looking approach today.
“As a region we face the twin challenges of population growth and the impact of climate change. As a company we have responded by building ever more resilient systems and this brand new facility just outside Perry is the latest example of that.
“As well as providing drinking water to millions, it’s part of a bigger jigsaw providing the essential infrastructure for sustainable growth in this important part of the country, underpinning the regional economy and ensuring this area remains a great place to live and work for generations to come.”
Anglian Water said in a statement: “Grafham Water has created hundreds of jobs and training opportunities, provided a hub for recreation and education, and a haven for wildlife, but fundamentally it is a working environment and vital part of the East of England’s water infrastructure, supplying millions of litres of clean, safe drinking water to millions of customers every day.”