The Dutch town of Katwijk is using bubbles to trap plastic trash in rivers with creative and innovative technique. Air is pumped through a perforated tube on the river bed forming a wall of bubbles in the water. The bubbles carry plastic waste to the surface and angle it toward the bank where it is collected for recycling. Katwijk’s Great Bubble Barrier is 120 meters long. It operates 24 hours a day, 7 days a week. It doesn’t disturb boats, and fish and other wildlife can pass through easily.
The concept was dreamed up in 2018 and tested on Amsterdam’s canals before Katwijk unveiled the biggest version yet. In tests, the Great Bubble Barrier caught 86% of river trash mopping up plastic pieces as small as 1mm. The bubbles also oxygenate the water preventing toxic algae growth. They also absorb sound from boats limiting disturbance for fish. A garbage truck’s worth of plastic enters the ocean every minute. 90% of the waste comes from just 10 rivers.
The UN Environment Program (UNEP) says 8 million tonnes of plastic waste end up in our oceans every year, and forecasts suggest this could double by 2025 if we don’t take drastic action.
Plastic Fischer was founded by three friends who were spurred into action after seeing the scale of plastic pollution in the Mekong River in Viet Nam while on holiday. According to the World Economic Forum (WEF), they quickly realized there was little active intervention to mitigate against the endless tide of plastic, so they decided to do something about it.
Applying a principle of locally built, low-tech and low-cost, they created their “TrashBoom” – a floating barrage that is stretched across a river to capture plastic waste as the current takes it downstream. The TrashBoom consists of floats made from standard plastic piping, attached to wire mesh barriers that resemble fencing. The mesh barrier extends down into the water to capture pieces of plastic floating below the surface. Plastic Fischer says the simplicity of the TrashBoom means the device can be built, repaired and scaled quickly in emerging markets.
The team at Plastic Fischer joined forces with the national army in Bandung, Indonesia, to develop and test the TrashBoom on one of the world’s most polluted rivers. After proving the concept of the TrashBoom, Plastic Fischer plans to rapidly scale up deployments in Indonesia, Viet Nam and India. The company will make the technology open source, to increase opportunities to capture plastic in rivers around the world. There are detailed instructions on how to build and operate the TrashBoom on the Plastic Fischer website.
The WEF reports that Finland’s RiverRecycle is also bringing an innovation mindset to the problem of ocean plastic. The business aims to install 500 cleaning and recycling points on the rivers that discharge the most plastic pollution into oceans. Communities hosting the company’s technology benefit not only from a cleaner environment, but also from new jobs created to service the recycling process.
Having 500 operational systems in place will take more than 3 million tonnes of waste out of the environment every year, while injecting over $300 million into host communities and providing enhanced income to more than 400,000 people, the company says.
RiverRecycle recognizes that hauling plastic out of rivers is only the first stage of a much wider process. As well as helping communities effectively manage plastic waste, its technology can offer “safe and fair work, and help to stimulate the economy by involving companies who will buy the end products of the river cleaning and recycling system”.
RiverRecycle’s projects include a facility on the Mithi River in Mumbai, India. The video below shows the waste collection process removing large amounts of plastic from the water. Plastic collected from the river is fed into a chemical recycling facility, creating value from waste that would otherwise end up in the ocean or the local environment. The project also provides training in waste management and has increased trash separation at source from households in Kurla and the surrounding areas.