Off-grid toilet unveiled at flower show

Prof Leon Williams said it was "hugely rewarding to see our work showcased" at the RHS Chelsea Flower Show

A team of academics have unveiled an off-grid toilet in an exhibit at the RHS Chelsea Flower Show.

Cranfield University in Bedfordshire said its Cranfield Circular Toilet was a self-contained system that could process waste on site.

It featured in the Gates Foundation's Garden of the Future at the prestigious horticultural show.

"It's not every day you see a toilet in a garden at the Chelsea Flower Show," admitted Prof Leon Williams, director of manufacturing and materials at the university.

"This is a brilliant example of research and engineering which has a real-world impact and could have applications across the world to improve sanitation."

He said the toilet drew on the university's expertise in advanced manufacturing, system integration and sustainable design.

The Garden of the Future won gold at the RHS Chelsea Flower Show

The toilet processes waste on site, without the need for connection to sewers or septic tanks.

It separates solid and liquid waste and uses advanced membrane filtration and thermal treatment to produce two useful by-products:

• Pathogen-free biochar fertiliser, a charcoal-like material that improves soil health and retains nutrients

• Clean, non-potable water, suitable for garden irrigation.

Dr Matt Collins, senior lecturer in product design engineering at Cranfield University, said the toilet was "helping us reimagine what's possible as we advance our goal to enable widespread use of safe, sustainable sanitation services to help drive positive health, economic, and gender equality outcomes for the world's poorest people."

The Garden of the Future includes climate-resilient crops such as sweet potato, chickpea and pigeon pea plants that could become more common in UK gardens as our climate evolves

The Garden of the Future - featuring the toilet - has already won gold at the show.

"Nearly half the world's population lacks access to safe sanitation – a crisis that impacts health, education and economic opportunity, especially for women and girls," said Doulaye Kone, director of water, sanitation and hygiene at the Gates Foundation.

"A warming climate is compounding these challenges, making the need for innovative, water-efficient sanitation solutions more urgent than ever."