A MULTI-million-pound overhaul of a water treatment works in Christchurch has been given the green light.

South West Water has had planning permission granted for improvements at its Knapp Mill site in Christchurch. The company proposed to invest £73m in an advanced chemical treatment process.

It submitted a scheme for a complex of 16 'large-scale buildings' and tanks, along with around 19 smaller chemical tanks at the northern end of the existing site.

The plans also involve underground pipelines, surface water drainage, vehicular access, car parking, delivery areas, as well as landscaping.

Once implemented, the changes would allow for a new water treatment process in which water is filtered through ceramic filters within a new enclosed structure rather than open tanks.

South West Water says the process upgrade will “deliver vital improvements in terms of the treatment process and greater water supply security through more resilient infrastructure that is better equipped to manage the impact of global climate change”.

Bournemouth Echo: The proposal for Knapp Mill The proposal for Knapp Mill (Image: South West Water)

Commenting on the proposal, a BCP planning officer said: “The applicant has chosen a technical water treatment solution that has a smaller scale than other available options, and it is clear to me that the proposed scale is necessary to achieve the required outcome of a secure supply of high-quality drinking water.”

Once the new operation is up and running, the old processing tanks and ancillary buildings are expected to become redundant.

At this stage, the applicant has not decided what will happen to the existing waterworks part of the site, but any future proposals would need separate planning permission, says BCP Council.

Last year, South West Water was set a deadline of March 2026 to complete upgrade works after the Drinking Water Inspectorate listed the site adjacent to the River Avon as an ‘aged asset’.

The regulator also described the existing processing technology on the site as ‘outdated’.

BCP Council approved the planning application on October 17.

It is not yet known when construction at Knapp Mill will begin