Using Robotics to Alleviate Marine Waste
As a citizen of a Mediterranean country, I take visits to the sea, whether it’s to enjoy a swim, camp, or eat in a nice sunny seafood restaurant, for granted. However, with the ever-increasing magnitude of marine trash, I doubt this will continue to be the case. I live in a country, where a large portion of the national economy depends on tourism, and Greece is known for its beautiful beaches. So, imagine planning and looking forward to your visit to the sea, just to see this:
Contrary to what of course you were expecting which is this:
Aside from personal interest and my disappointment with the state of ocean pollution, this has been a problem whose consequences and importance have wrongfully been neglected by many. Here are a couple of statistics to illustrate the massive global scale of the problem:
- Oceans contain more than 60 million tonnes of waste, with an estimated 10 million tons of plastic entering our oceans yearly.
- Currently, about 50–75 trillion pieces of plastic and microplastics are in the ocean, accounting for up to 60–90% of the marine pollution found.
- Around 40% of the world’s ocean surface is covered in plastic
- By 2050, the population of fish will be outnumbered by our dumped plastics, as ocean plastic pollution is on track to triple by then
- This debris forms giant garbage patches; there are five of them in the world, the largest is the Great Pacific Garbage Patch, which includes an estimated 1.8 trillion pieces of trash and covers an area twice the size of Texas.
Marine trash consists of all manufactured products, most of which are plastic, that end up in the ocean through littering, storm winds, or poor waste management. The most common types of marine debris include: shopping bags, bottles, bottle caps, cigarette butts, food wrappers, and fishing gear, though construction materials such as concrete blocks, tires, or car batteries have also been found.
Why are we focusing on plastic so much?
Plastic waste is particularly problematic as a pollutant because it is so long-lasting, it is one of the most enduring materials we have ever created. It is produced from fossil fuels, and despite having enabled many inventions we use in our daily lives, its environmental threat can not be overlooked. The EPA (Environmental Protection Agency) has stated that 100% of all plastics human beings have ever created are still in existence in some form. It is even more alarming that currently, 79% of plastics are sent to landfills or the ocean, while only 9% are recycled, and 12% get incinerated (creating air pollution, but this is a topic for another day). Moreover, plastic may take up to 1000 years to decompose, a process that releases harmful greenhouse gases, and even then it does not fully degrade, rather it becomes microplastic, which is another problem in itself.
Microplastics:
Microplastics are tiny plastics, less than five millimeters in diameter, causing harm to the environment and animal health.
There are two categories of microplastics:
- Primary: result from commercial product development (manufactured to be less than 5mm) e.g cosmetics, microfibers that shed from clothing, and other textiles like fishing nets
- Secondary: result from the breakdown of larger plastics e.g water bottles (breakdown is caused by exposure to environmental factors e.g sun radiation, ocean waves). The majority of sources of secondary microplastics are single-use plastics, such as straws.
These pieces are too small to be caught by existing filters being discharged by water treatment systems. A recent study of the San Francisco Bay found that eight wastewater treatment plants discharged an average of 490,000 particles of microplastic per day into the Bay.
The Threat
This trash poses dangers to both humans and animals. Fish become tangled and injured in the debris, and some animals mistake items like plastic bags for food and eat them. Tiny organisms feed on microplastic and absorb the chemicals from the plastic into their tissues. When small organisms that consume microplastics are eaten by larger animals, the toxic chemicals then become part of their tissues. In this way, microplastic pollution migrates up the food chain, eventually becoming part of the food that humans eat.
Effect on Humans, Marine Life, and the Environment:
Humans:
- Coastal water contamination is responsible for 250 million clinical cases of human diseases annually.
- At the current rate, by the end of the century, our waters will be 150% more acidic than now.
- 80% of sewage discharged into the Mediterranean Sea is untreated.
- Contaminated shellfish is the cause of 50,000–100,000 deaths annually due to damaged immune systems and cancer.
- The direct medical and health costs of polluted waters are $16 Billion globally each year.
- The majority of fish we consume have ingested plastic and microfibers.
Marine Life:
- 100 million marine animals die each year from plastic waste alone.
- 100,000 marine animals die from getting entangled in plastic yearly — these are just the creatures we find!
- 236,000 tons of plastic discarded annually in the sea are ingestible microplastics that marine creatures mistake for food.
- 12–14,000 tons of plastic are ingested by North Pacific fish yearly.
- Marine plastic pollution is found in 100% of turtles, 59% of whales, and 36% of seals.
- 500 marine locations are now recorded as dead zones globally, currently the size of the United Kingdom’s surface (245,000 km²)
- Coral reefs house some 25% of all marine life known to man. When it comes in contact with marine plastic, the probability of it dying goes from 4%-89%.
The Causes
Waste can make its way to the ocean through:
- Littering
- Sewage
- Ocean Mining
- Oil Spills
- Agricultural Runoff
- Toxic Chemicals
- Air Pollutants
- Maritime Transport
80% of all pollution in our oceans comes from land-based sources, including agriculture runoff, untreated sewage, and discharge of nutrients, and pesticides. A misconception that is debunked by this is: oil spills are not the biggest problem! Of course, they are vastly dangerous to the oceans, but only 12% of oil in the ocean comes from actual spills, the rest leaks in from drains, rivers, and road runoffs. On the other hand, agricultural runoff which is mostly fertilizers causes algal blooms to flourish and dissolve the water’s oxygen levels. Since 1984, these harmful algal-based blooms have tripled, closing beaches and killing fish.
Some more interesting causes:
- Most developing countries dispose of 90% of water, and 70% of industrial waste into our oceans without treatment.
- From 1950–1998 over 100 nuclear blast tests occurred in our oceans.
- Annually, the Mississippi River flows 1.5 million tons of nitrogen pollution into the Gulf of Mexico.
Why do we need to act now?
It is estimated that in the past 10 years, we’ve made more plastic than in the last century. If we do not find other alternatives for plastics and a set of solutions that can be implemented at scale to this problem, the effects will only compound in the future. With the global demand for freshwater rising and the critical role oceans play in tackling climate change (70% of the oxygen we breathe is directly created by marine plants, while 30% of our CO2 emissions are absorbed by our oceans), this is a matter of huge significance and requires immediate attention.
How we can use Robotics?
Currently, human divers pick up waste in some marine areas but this is far from an ideal solution. Experienced divers can be hard to find, and the amount of time they can spend underwater is limited by their air supply. Other than the fact that some areas may be unsafe for humans, this is simply an unreliable and inefficient recommendation. Nonetheless, it is the problems of this process that an automated robot could resolve in a more efficient, cost-effective, and safer way. Below are a couple of early staged efforts for using robotics to tackle water pollution.
SeaClear’s Team of Robots
The SeaClear project consists of four robots that collaborate to remove litter from the oceans. A robotic vessel, that remains on the water’s surface, acts as a hub containing the central brain of the system and providing energy to the other robots. The system uses AI, to distinguish waste from animals. One of the two underwater robots is responsible for identifying the trash by traveling close to the sea bed and scanning it with its cameras and sonar. The second robot is equipped with a gripper and suction device to pick up the items found by its companion and deposits them into a tethered basket placed on the seafloor, which will later be carried to the surface. A drone, the fourth and last robot on the team, helps search for garbage when the water is clear, and identifies obstacles such as ships.
Magnetic Nanobots
Nanorobots developed by the University of Chemistry and Technology in Prague have been created to remove pollutants from water. The nanobots, which are about 200 nanometers wide, are propelled by magnets, so their movements can be controlled. They consist of a temperature-sensitive polymer material, that acts like tiny hands that can pick up and dispose of pollutants and iron oxide that makes the nanobots magnetic. The addition of oxygen and hydrogen atoms to the iron oxide enables the attachment to targeted pollutants. At 5°C, the nanorobots are dispersed in water. When the temperature is raised to 25°C, the nanorobots clump together, trapping any pollutants between them. They can then be removed from the water using a magnet and cooled down to dispose of the pollutants. They don’t need any fuel to operate and can be used repeatedly, making them sustainable and cost-effective, while the design can be moderated to target particular chemical particles.
Ocean Cleanup
The Ocean Cleanup, a Dutch nonprofit organization, employs a 2,000ft long unmanned floating barrier in the Pacific Ocean and solar-powered autonomous trash collectors called “Interceptors” deployed in rivers (90% of the ocean’s waste comes from the world’s 10 largest rivers) in the Dominican Republic, Malaysia, and Indonesia. They intend to expand this to the 1,000 most polluted rivers by 2025. In October 2020, it succeeded in capturing 60 bags of trash, recycling them, and selling them as sunglasses.
Some other cool ideas are: Clearbot Neo, Robotic Crabs that monitor the seafloor, Bots that disperse coral babies in the Great Barrier Reef
The Gap
To effectively tackle the problem at scale, robots need to be affordable, easily accessible and there have to be economic incentives. A proposed method to make the economics work is repurposing the underwater waste into something useful which can later be sold. Even though, robots present the ability to clean the oceans at a level we have never before been able to match, this will never be enough unless the sources and quantities of pollution are minimized. In addition, by identifying the biggest polluters, more efficient methods of addressing the root causes can be formulated.
I’m Panagiotis, an aspiring mechanical engineer learning about the application of emerging technologies to tackle global problems. If you’re someone working on the application of robotics to tackle pollution, I would love to talk. (LinkedIn)
