Water filtration system will be Europe’s biggest

Norwich is dependent on the River Wensum for its water supplies, parts of which contains Sites of Special Scientific Interest and Special Areas of Conservation

In early April Anglian Water began installing a state of the art filtration system at its Water Treatment Works in Norwich as part of its “£36million scheme to keep customers’ taps running for decades to come and protect the local environment at the same time.”

The filtration system will seemingly be the largest of its kind in Europe.

Work on the scheme began in 2017 and it makes up part of the half a billion pounds the water company is investing in the region between 2015 and 2020. The scheme will be completed later this year, and will supplement the existing treatment process.

Offering context in relation to the investment, the utility said the city is growing. Norfolk is expected to be home to more than one million people by 2034, many of whom will choose to live in Norwich – one of the UK’s fastest growing cities. This combined with being in one of the driest counties in the UK means investment is required to ensure there is a ready supply of water.

Historically, the Costessey Pits have been an important part of the water treatment process by providing natural storage for water from the Wensum prior to its treatment. This initial phase allows solids and sediment naturally occurring in the river to settle out from the water before it’s pumped to the Heigham Water Treatment Works for further treatment before entering supply.

Parts of the River Wensum are designated Sites of Special Scientific Interest and Special Areas of Conservation. The Costessey Pits area specifically has a rich and diverse environment that needs protecting.

In the future, Anglian Water will not be able take enough water from Costessey alone to support the needs of the growing population without having a detrimental impact on the environment. To protect the environment against this, more water will need to be taken further downstream in the Wensum – nearer Heigham Water Treatment Works itself. At Heigham, water flows are higher as the River Tud joins the River Wensum.

These higher levels mean Anglian Water can take the water needed from the river without damaging the delicate ecosystem near Costessey. This hasn’t been possible previously because the water at this point in the river contained too much sediment to be treated without settling first; but the installation of the new filtration system will solve this problem and treat the water to the exceptional standards required.