Among the speedboats, luxury yachts and wooden fishing boats parked in a Hong Kong marina, one vessel is more unusual: an unassuming, 3-meter (10-foot) unmanned catamaran that deftly glides through the water, gobbling up floating trash like Pac-Man.
Discarded plastic bottles, juice boxes and cartons are carried along a conveyor belt through a gap at the front of the ship, where cameras capture the collected trash before it is dumped into a collection basket in the center of the ship.
According to the US non-profit Oceana, an estimated 33 billion pounds (15 billion kilograms) of plastic waste enters the ocean every year – the equivalent of dumping two garbage trucks' worth of trash into the ocean every minute. Most of it finds its way into the ocean via rivers and coastlines.
“We have garbage trucks on land, why not something that purifies the water?” Siddhant Gupta, co-founder of Clearbot, the marine tech startup that developed the boat, told CNN.
Clearbot is hoping to change that with solar-powered, autonomous vessels like the Hong Kong one, which can process 80 kilograms (176 pounds) of waste per hour and carry 200 kilograms (441 pounds) of waste.
In the process, the company hopes to help advance the marine industry, which is heavily reliant on human power and fossil fuels. “We're building the future of boats and ships,” Gupta said.
A Clearbot trash boat cleans up a marina in Hong Kong. – Amy Gunia/CNN
Decarbonizing 'dull, dirty and dangerous' jobs
Clearbot, which began as a university project, was founded in 2020. Despite COVID-19 shutdowns and fundraising challenges, the company has expanded rapidly. Currently, the company operates around a dozen vessels for various government and corporate clients in Hong Kong, Thailand and India.
The first of the Class 3 vessels, a 4-meter (13-foot) long vessel, will be able to collect 200 kilograms (441 pounds) of trash per hour, carry a 1.5-ton (3,300-pound) load and collect the trash onto a barge towed behind it, traveling at about 3 knots (3.5 miles per hour).
These include a project to collect waste from the religiously significant but highly polluted Ganges River in the Indian city of Kolkata, and another in northeastern India's Umiam Lake, where waste flows downstream from mountain villages.
How the catch is used varies depending on the project and region, but often involves working with local waste management and recycling companies.
The company's boats can be remotely controlled through an online dashboard or set to operate autonomously.
Clearbot has developed algorithms that enable ships to navigate around obstacles and analyze what is collected, providing data so authorities can take action to stop waste from entering waterways.
“Three years ago, this was a PowerPoint presentation,” said Gupta, who studied computer engineering and robotics at the University of Hong Kong. “Today, this is reality.”
But the ships can do more than just suck up trash: Gupta says Clearbot's fleet can take on plenty of other “dull, dirty and dangerous” jobs.
In Bangkok, Thailand, the company's ships are clearing algae from lakes using the same conveyor belt system used for trash collection, but with a finer mesh material to stop the algae seeping out.
In Hong Kong's Mai Po Nature Reserve, a resting place for migratory birds, Clearbot's vessels are removing the eggs of the invasive apple snail, using artificial intelligence models to detect the eggs and stop them from breeding. To do so, a type of robotic arm known as an “agitator” shakes the eggs off vegetation and sprays them with water from nozzles.
The boat can be equipped with a variety of sensors and tools to survey the bottom of waterways, test water quality, and take samples. A cutter can remove invasive plants like water hyacinth, and an attachable boom can help clean up oil spills.
Gupta said the fleet could decarbonize maritime operations across a range of applications by replacing ships that run on fossil fuels. The larger vessels would have solar panels on top and batteries that could run for eight hours, while the smaller vessels, which could run for four hours, would need to be recharged at a docking station.
A robot ship? “Whatever.”
Clearbot isn't the only company using technology to improve aquatic environments. Entrepreneurs, academics, and NGOs around the world are racing to develop innovative technologies to clean up waterways and gather more information about what's going on below the surface, from automated floating trash bins to containment booms to fish-like underwater drones. Other companies, such as Netherlands-based RunMarine Technology, are also working on developing autonomous waste collection vessels.
Robert C. Brears, founder of water security platform Our Future Water, told CNN that successful innovation will depend on who is ahead in terms of AI technology and can deliver the best hardware capabilities.
He added that there is a desperate need for technology to provide better information on water-related issues. “Water quality and water supply affect human health and survival, yet there is a real lack of monitoring and data,” he said.
Clearbot is now focused on scaling up, with Gupta hoping to have 20 ships in place by March 2025 and 50 operational within two years.
He likened the robot boat to the Roomba-like disinfection robots that operate in many of Hong Kong's shopping malls, which he said were frowned upon a few years ago but have now become commonplace.
“When you see this at the port, you think, 'What?' It's normal,” Gupta said. “We want to be ubiquitous.”
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