A revolutionary new maritime “vacuum cleaner” which could suck more than 20 billion tonnes of plastic waste out of the world’s oceans – solving one of our most intractable environmental problems – has started sea trials off the Dutch coast.
Invented three years ago by a then 19-year-old engineering student, the 100-metre-long prototype was towed 23km into the North Sea last Thursday, where its performance in storm conditions will be monitored over the next six months using a system of remote-controlled sensors – before it’s moved to the Japanese island of Tsushima for a second phase of tests.
Ultimately, the aim is to use the new Ocean Clean-up boom – it doesn’t have a catchier title yet – to tackle the greatest concentration of sea-borne plastic debris on the planet in what’s known as “the Pacific trash vortex”, a system of rotating currents discovered in the North Pacific in the late 1980s.The vortex is roughly between 135-155 degrees west and 35-42 degrees north, and is best described as a toxic mix of plastics, chemical sludge and other debris that has devastated marine ecosystems over an area conservatively estimated at twice the size of the continental United States.
The trials were preceded by three years of computer modelling. If they are successful, it’s expected that the final design of the clean-up unit, comprising 100km of interlinked floating booms and processing platforms – 1,000 times the size of the prototype – will be deployed in the heart of the vortex, somewhere between California and Hawaii, by 2020.
There are many aspects of this Dutch piece of innovation that are remarkable, but the key to its design is its system of floating booms similar to those used the world over by salvage companies from the Netherlands – including in Bantry Bay after the Betelgeuse tanker disaster of 1979 – to contain and remove large oil slicks.
In this case, the vulcanised rubber booms have a different function though: they act as funnels that are angled so that they passively harness the ocean currents to channel – effectively float – the debris into its large V-shaped collection units, no matter how rough the weather.
What’s technologically unique about this capture system is that while plastics and debris are collected, sea-life is totally unaffected. Because there are no nets and the speed of the filtering is very slow, fish – and even, believe it or not, plankton – pass by unhindered. At the same time, while the plastics are being removed, sea water processors will be located where the platform is anchored to the sea bed – and these will generate electricity, enough at least, along with solar units on the surface, to provide power when the sea-going tenders arrive periodically to empty its multiple collection units.
Because of the unforgiving ocean in which it will be operating, and because it will be relatively light, the boom will be capable of being anchored at depths of up to 4.5km, which is almost twice as deep as has been possible in the past with other floating structures.
That’s why the current North Sea tests are so important to its ability to function virtually endlessly in the most hostile of environments. “The main objective is to make sure we can build something that can survive at sea for years, if not decades,” says 21-year-old Boyan Slat, the engineering student at world-renowned Delft University of Technology who first came up with this design when he was 19 – and has postponed finishing his degree until he can bring it to fruition.
“We want to test the efficiency of the system, understand its behaviour, and see what damage it suffers from abrasion or fatigue. The North Sea can be a pretty violent place. If it can stay whole here, it can stay whole anywhere.”
Perhaps most remarkably in funding terms, while the final unit – the booms plus collection pods – is expected to cost only about €300,000 to build, the team behind it estimate that by recycling the plastic it collects, it can generate about €500 million a year, making it a potentially profitable environmental solution.
Even up to now, in the design and development phase, given what it is capable of achieving, the costs have been pretty modest.
When Slat – then an unknown student in the Netherlands – first went public with his design in 2014, he decided to set up the Ocean Clean-up Foundation and see what he could raise through crowd funding. To his amazement, almost 40,000 people were impressed enough to donate a total of €2 million over just two months.
Since then, the Dutch government has become involved. It has seen the results of tests carried out at the Maritime Research Institute of the Netherlands at Wageningen University, which specialises in environmental science and has been highly impressed, contributing a reported €500,000 so far.
That's been matched by Dutch dredging and marine contractors, Royal Boskalis Westminster, who bring global industry expertise to the table and whose chief executive, Peter Berdowski, has described the project as "very inspiring". Another backer, who remains anonymous, is said to have signed a cheque for €1.5 million.
All this has turned Slat overnight into not just an entrepreneur and an innovator but also into a new Dutch icon and a role model for his peers to such an extent that he's to join prime minister Mark Rutte as part of a trade and climate mission to Indonesia in November.
Inventions with the potential to benefit the global environment on such a scale and so cheaply are rare and internationally very cool. "I am certain we can use our political influence with other governments, businesses and international institutions to fund this on an even bigger and more ambitious scale," says Dutch environment minister Sharon Dijksma.
“We are used to fronting public-private partnerships like this. When we’re convinced, that’s not a problem. When this project is a success, philanthropists all over the world will be standing in line asking to join us.”
She’s probably right. One idea already being floated is that the clean-up boom could be used across the mouths of major rivers where they meet the ocean to catch some of the 800 metric tonnes of plastic that pours into the Pacific and Indian oceans every year – before it reaches deeper waters.
This is something that’s likely to be discussed by the Dutch delegation with the Indonesian government. It’s already been noted by officials in The Hague that the Indonesian archipelago has the world’s second-highest concentration of shoreline debris, after Sicily.
Is a complete clean-up really possible? It seems so, but it will take time. Slat and his team believe that with the system working flat-out, collecting half the plastic in the North Pacific should take about a decade – not at all bad considering how long it’s taken to build up there.
“One of the problems with environmental work in these waters is that there isn’t any real imagery of this garbage because it’s spread over millions of square kilometres and can’t be seen on satellite photographs,” says Slat.
“By collecting it in our units, however, people will be able to get some impression of just how large-scale this is. I hope it will bring home the importance of recycling, in every home – and reducing our consumption of plastic packaging.”