Wessex Water has achieved an estimated 75% saving in capital expenditure by retrofitting an abandoned 12m-diameter onsite sludge tank at a rural water recycling facility in Dorset in a process upgrade needed to meet population growth in the town of Sherborne.

The utility doubled process capacity by opting to retrofit the repurposed circular sludge tank after initially planning to construct two to three additional 30m-diameter trickling filters.

Andrew Gulliford, process design manager at Wessex Water, identified WPL’s Hybrid-SAF™ enhanced biological treatment process as more cost-efficient than the planned trickling filters.

Working together the partners calculated that a potential cost-saving of 75% in capital expenditure could be achieved by retrofitting the existing infrastructure with WPL’s technology as an alternative to the planned project. The early collaboration delivered multiple delivery and operational benefits by identifying repurposing potential of an the abandoned tank was during the initial planning stages of the project.

Off-site manufacture of the modular process technology cells also meant that the onsite project delivery time would be a couple of days, rather than a possible 12-months for the civils work required for new trickling filters.

WPL’s technical director Andrew Baird said the early involvement and collaborative working meant the best solution for the site could be identified very early on.

Andrew Gulliford, process design manager at Wessex Water commented:

“Working closely with WPL at the earliest stages of planning for Sherborne water recycling facility meant that together we could completely reimagine the possibilities at this constrained site. Wessex Water customers will benefit from the 75% cost saving on this project and the energy efficiencies achieved will help deliver our sustainability targets.”