If you buy organic carrots from a major retailer in the UK, they have likely been washed with water filtered through a reed bed at Produce World’s factory in Yaxley, near Peterborough.
“As an organic site, we invested in a natural water treatment process – a reed bed, to clean our water instead of using chemicals,” says Jamie Tointon, Head of Operations at Produce World.
Agri-Tech East, the UK’s largest membership organisation for agri-tech, is holding a Water SIG (Special Interest Group) visit to the Yaxley site on 17 May, where attendees can learn about the installation and maintenance of a reed bed.
89% of water used by Produce World is processed through the natural filtration system which holds 12,000 cubic metres of water. The reed species used are the Common Reed (Phragmites Australis) and Bulrush (Typha Latifoli).
“As an organic facility, the decision to install a reedbed was more about narrative than economic benefits,” says Jamie. “However, when you break it down, the site was spending about £50,000 a year on chemicals. For a large site, our water bill is now relatively low.”
How a reed bed systems work
Jamie explains: “Dams slow the flow of water as it travels along the river. The water is then passed through four separate gravel filtration processes, giving solids in the water time to settle.
“The reeds transfer oxygen to their roots, which is utilised by diverse microorganisms. These microorganisms enhance the biological treatment function of the system. Water soaks through four individual pea gravel beds to be pumped into a holding lagoon. It’s a closed loop system, so clean water goes into the factory each morning for washing the vegetables, and the dirty water is returned to the lagoon in the evening for processing.”
The company also states that there is little need for maintenance, other than managing the flow rate. Jamie believes that with enough space, a reed bed could be used by agribusinesses that use high volumes of water. Visitors can get a good feel for the size during the upcoming Agri-Tech East event.