Aestuarium: harvesting fresh water and awards
On our planet, water is synonymous to seawater. Only 3% of the Earth’s water is fresh, and most of that is locked away in snow and ice near the poles. The world’s 8 billion people, along with their livestock and crops, must therefore rely on just 1% of all water. Seawater could provide a welcome supplement to our dwindling freshwater supplies, but it contains far too much salt. An average bucket of seawater holds two coffee mugs’ worth.
Anirudh Rajesh, an alumnus of the Maastricht Science Programme (MSP), experienced firsthand how severe freshwater shortages can be while living in Chennai, India. Despite the city’s coastal location, it faces acute water shortage every summer. “We would get just one hour of undrinkable water per day,” he recalls. Today, Anirudh is CEO of Aestuarium, a startup company based at the Chemelot Campus, that uses bacteria to extract salt from seawater.
Bacteria at work
Desalinating seawater is an energy-intensive and costly process, typically achieved through evaporation or reverse osmosis. In 2022, a group of students at Maastricht University’s Faculty of Science and Engineering proposed a more sustainable and affordable alternative. With guidance from their supervisor, Erik Steen Redeker, they discovered that researchers had previously used bacteria to remove 20% of the salt from seawater, yet even then, a bucket of water would still contain over a mug and a half of salt. The team was determined to improve on this.
In the MSP laboratory, the students engineered bacteria to absorb and retain more salt within their cells. “Through genetic modification, we introduce proteins that enable the bacteria to draw salt from their surroundings,” explains Anirudh. “We then ensure the bacteria retain the salt until we prompt them to release it.”
50% less salt, 80% less energy
The young researchers have since achieved a breakthrough: their bacteria can now remove nearly half of the salt from seawater. “Completely removing all of it isn’t feasible,” Anirudh admits. “Our goal is to pre-treat the water so that traditional desalination methods can then produce freshwater with 80% less energy.”
Bridging science and entrepreneurship
Four members of the original student team, joined by two alumni of the Maastricht Science Programme and the master’s programme Financial Economics, went on to establish Aestuarium as an independent company in 2023. “Roy Broersma from the Center for Entrepreneurship and Innovation was instrumental in helping us bridge the gap between scientific research and business,” Anirudh notes.
The Future
Thanks to numerous awards (see box) and several grants, Anirudh, his team, and ten interns are now developing a prototype capable of processing 50 litres of seawater per day. Scaling up to 1,000 and 10,000 litres per day is already in the pipeline, with plans to eventually build a full-scale demonstration plant. If Aestuarium’s bacteria perform as hoped and the team continues to excel both scientifically and commercially, residents of Chennai and other water-scarce regions may in the future drink clean water that sprang from an idea born at Maastricht University.
