Dalhousie researchers design low-cost device that can help fight water scarcity

A dome-shaped device floating in Halifax's Northwest Arm could easily be confused with a buoy, but it is actually a contraption meant to turn ocean water into fresh water. 

Designed by two Dalhousie University researchers, it was created using recycled tires and other cheap materials to have a low-cost, environmentally sustainable method to obtain drinking water. 

Mita Dasog, an associate professor in Dalhousie's chemistry department, said the project aimed to create a device that would be cheap to make and self-sufficient.

According to a United Nations report, in 2022, around 2.2 billion people across the world don't have access to water that is safe to drink.

"Seventy per cent of the earth's surface is covered in water, most of it is saltwater, which we cannot drink," said Dasog. "Being able to convert saltwater into freshwater is a very energy-intensive process."

How it works

Matthew Margeson, co-researcher of the project, said the device uses solar power, making it both environmentally friendly and functional in communities with no access to electricity.  

To demonstrate, he left it on the shore of Horseshoe Island Park for a few hours. 

The system uses cotton wicks at the bottom of the device to absorb ocean water and transport it to the dome.

Inside the dome, a fibre coated with powdered titanium carbide made from recycled tires captures sunlight and converts it into heat. The heat evaporates the water, leaving the salt behind.

The condensate on the dome is collected in a sealed bag. 

"It can generate up to about 3.5 litres of water, so enough to sustain an individual," said Margerson, noting the current model is meant to meet the daily needs for one person. 

In one morning, the device collected enough water to fill a glass. 

Affordable option

Margeson said all materials needed to create the device cost a total of $5.

"Being able to incorporate a waste material actually helps to reduce that cost," he said. "So we incorporate waste tire rubbers that we just pick up from the garbage."

Dasog added that the device desalinates, disinfects and decontaminates the water for less than one cent per litre. 

"If you think about countries that are currently facing water scarcity, they don't have access to abundant energy or economy," she said.

"So being able to [desalinate] this in a cheap fashion using a renewable source of energy was very important to us."

This gadget passed all of its tests in Nova Scotia waters, proving it can float over waves and high tides and work even on cloudy days. 

The next step is to test it in South Asia, where the objective will be to measure its effectiveness in a real community.