A team of Australian researchers has discovered the secret to turning fog into drinkable water.
Harvesting atmospheric humidity has long been a part of scientific discussion in the hopes of addressing the more than 1.2 billion people in the world who do not have ready access to safe water.
It was also the conundrum tasked to 98 international research groups in this year’s the Water Abundance Xprize competition.
In order to be listed among the five finalists, the Newcastle University Hydro Harvest team needed to create a renewable method of extracting from the air at least 2,000 litres of water per day, at a cost of two cents per litre.
Spearheaded by Professor Behdad Moghtederi, the team created a device that uses silica gel balls to draw moisture out of the night air.
During the day, the balls are sealed into a perspex case that can reach up to 80 degrees in direct sunlight. The water is collected as it evaporates out of the balls.
“Resources for fresh water are limited, we have to think differently about how to solve that. Humidity was the obvious solution,” said Professor Moghtederi.
The project represents the culmination of 18 months’ work, and more eight years’ research.
“It’s a simple system that can be build in third world countries, where it really is needed most,” said Professor Moghtederi.
For the system to work best, the humidity level in the air needs to be above 10 per cent, and it is that requirement that positions Wagga as an ideal catchment site.
“For most of Australia, it’s not a problem, 10 per cent humidity is easy to find. But foggy areas make the process easier.”
On average, the air is 98 per cent water vapour, and two per cent water particles. When the particles remain high in the atmosphere, it appears as clouds. As the particles drop to ground level, it becomes fog.
Without having to filter through the vapour, the device has a greater chance of collecting the maximum moisture.
But even in low-fog areas, the air is bound to fall below dew point eventually.
“The dryer the environment, the larger the unit needs to be, which will impact the cost,” said Professor Moghtederi.
“But even the driest cities still have moisture. Saudi Arabia for example, it is a very hot and dry city, but at night the temperature can drop significantly which shoots up the humidity.”
Professor Moghtederi considers the finalist accolade to be “icing on the cake”, with the device likely to revolutionise water harvesting regardless of the competition’s outcome.
“We’re in talks with government agencies about how it can collect 5,000 litres or more for local townships. We also have a dialogue going in Africa, but we would like to explore the option in Australia first,” Professor Moghtederi said.
“Regardless of whether we win or not, we’re pressing ahead with all of that.”