"You could either use that in agriculture and it's good for improving the water holding capacity of soils; it's good for nutrient availability… and creates good soil structure," he added.
Solar power is an increasingly important part of the global energy mix and last year the International Energy Agency said the sun could be the world's largest source of electricity by 2050.
"Solar is an ideal energy source… there's really a renaissance in solar energy today," Linden said. "The way we can collect it is very efficient and it's a free energy source," he added.
Linden did admit however that using solar power presented own challenges. "It's certainly not going to be a solution for areas that have high cloud cover and a long, long rainy season," he said.
"We've done some analysis looking at patterns of light coverage in different parts of the world and we've come up with a map of where our toilet could work well… North Africa, the Middle East, parts of India, some parts in the Arctic, say, where there's a lot of sunlight."
Linden said that it would cost a family of four around $12,000 to buy a first-generation toilet, and said that Sol-Char Sanitation's main goal was driving that cost down. It is hoped that a range of factors – from scaling up production to using different manufacturing methods and more affordable materials – will help to do just that.
by Anmar Frangoul