Amid the speedboats, luxury yachts and wooden fishing boats moored in a Hong Kong marina, another kind of craft maneuvers. It looks inconspicuous, but as the three-meter-long (10-foot-long) unmanned catamaran moves nimbly through the water, it consumes trash floating on its surface in a Pac-Man-like manner.
Discarded plastic water bottles, juice cartons and cartons pass through an opening at the front of the boat and are transported up a conveyor belt. A camera photographs the haul before the waste is deposited in a collection basket in the middle of the boat.
An estimated 33 billion pounds According to the US non-profit organisation Oceana, 15 billion kilos of plastic waste ends up in the oceans every year – the equivalent of dumping two garbage trucks worth of waste into the ocean every minute. Most much of it ends up there via rivers and coastlines.
“We have garbage trucks for the land. Why don’t we have something to clean the water?” Sidhant Gupta, co-founder of marine tech startup Clearbot, which developed the boat, told CNN.
Clearbot is trying to change that with its autonomous, solar-powered boats, like those in Hong Kong, which can process 80 kilos of waste per hour and carry 200 kilos on board.
In the process, it hopes to help evolve the maritime industry, which relies heavily on manpower and fossil fuels. “We are building the future of boats and ships,” Gupta said.
Decarbonising ‘boring, dirty or dangerous’ work
Clearbot, which started as a university project, was founded in 2020. Despite Covid-19 closures and a tough fundraising environment, it has been developing rapidly. Today, it operates around a dozen boats for various government agencies and corporate clients in Hong Kong, Thailand and India.
The first of its Class 3 vessels, the larger four-meter (13-foot) boat can collect 200 kilograms (441 pounds) of trash per hour and carry a payload of 1.5 metric tons (3,300 pounds), collecting the trash in a barge towed behind it. It travels at about three knots (3.5 miles per hour).
That includes one that collects waste from the religiously important but extremely polluted Ganga River, which flows through the city of Kolkata in India. Another operates in the Umiam Lake in northeastern India, where waste flows downstream from mountain villages.
What happens to the catch varies by project and region, but often involves working with local waste management and recycling companies.
The boats can be controlled remotely via an online dashboard, or set to sail autonomously.
Clearbot has developed algorithms that allow the boat to avoid obstacles and analyse what it collects, providing data that authorities can use to take action to stem the flow of waste into waterways.
“Three years ago, this was a PowerPoint presentation,” said Gupta, who studied computer engineering and robotics at the University of Hong Kong. “Today, it’s real.”
But the boats don’t stop at vacuuming up waste. According to Gupta, there are many other “dull, dirty or dangerous” jobs that the Clearbot fleet is capable of.
In Bangkok, Thailand, the company’s boats are used to remove algae from lakes, using the same conveyor belt system as for waste, but with finer mesh to prevent the algae from seeping through.
In Hong Kong’s Mai Po Nature Reserve, a resting place for migratory birds, a Clearbot boat has been working to retrieve the eggs of invasive apple snails – which it can detect using an artificial intelligence model – to prevent them from multiplying. To do this, an “agitator,” a kind of robotic arm, shakes the eggs off the plants and a spray nozzle sprays water onto the eggs.
The boats can be equipped with a variety of other sensors and tools to map the bottom of waterways, test water quality and collect samples. Cutters can remove invasive plants such as hyacinth, and an attachable boom can help clean up oil spills.
The fleet has the potential to decarbonize maritime operations in a range of applications by replacing fossil-fuel-powered boats, Gupta said. The larger boat has solar panels on the roof and an eight-hour battery, while the smaller boat, which can sail for four hours, requires charging at the dock.
A robot boat? ‘So what?’
Clearbot isn’t the only company using technology to improve aquatic environments. Entrepreneurs, academics and NGOs around the world are busy developing innovations – from automated floating waste bins Unpleasant containment is flourishing tO fishy underwater drones – that clean waterways and capture more information about what’s happening beneath the surface. Other companies, such as Netherlands-based RanMarine Technology, are also working on autonomous waste collection vessels.
Robert C. Brears, founder of the water safety platform Our Future Water, told CNN that which innovation will be successful will likely depend on which AI technology can take the lead in enabling the best hardware functionality.
He added that technology that provides better information on water-related issues is desperately needed. “Monitoring and data are really lacking,” he said, despite the impact that water quality and availability have on human health and survival.
Clearbot is now focused on scaling up, with Gupta hoping to have 20 boats in operation by March 2025 and 50 in operation within two years.
He compared the robot boats to the Roomba-like disinfection robots that can be found in many Hong Kong shopping malls. A few years ago, he said, they were surprising, but now they are considered quite normal.
“You should be able to see these in the ports and think, ‘Whatevs,’ because it’s so normal,” Gupta said. “We want to be ubiquitous.”
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