Ocean debris is concentrated in a number of ocean garbage patches or “gyres”, where a huge amount of debris, mostly consisting of floating plastics waste is spiralling until in the end it sinks to the ocean floor.
The Ocean Cleanup (TOC) has been celebrated for a big technical solution to ocean debris. A young engineering student, Boyan Slat, has developed a big idea into a project, has convinced many people to pay into a crowd funding campaign, and has set off a massive research and planning project. He won awards and praise, not the least from the United Nations. Others too are working on similar solutions, for example Pacific Garbage Screening (PGS), who received an award from the German Government.
Ocean scientists like Deep Sea News criticise these approaches, because the big contraptions designed to collect debris will serve as huge fish aggregating devices and attract huge numbers of marine animals. So far the technology does not appear to be able to separate debris from marine life, endangering the fauna of the high seas.
In this blog post I am looking at this proposed technology from the perspective of waste management. I made my observations based on The Ocean Cleanup’s feasibility study because it was available on the internet, but I am quite convinced that looking at the feasibility studies of similar enterprises will come up with a similar result.
My conclusion is that this method is neither efficient, nor does it solve the problem. The alternative would be simple, more efficient, and give hundreds of thousands of the world’s poorest families more income: better waste management practices on land.
On page 441, TOC’s feasibility study claims that “Based on this collected evidence, we conclude The Ocean Cleanup Array likely is a feasible and viable method for large-scale, passive and efficient removal of floating plastic from the Great Pacific Garbage Patch.”
Apart from the term “likely” (which to me means “not necessarily”, but I may be wrong, I’m German, not a native English speaker), I think that one of the authors may have confused the terms “efficient” and “effective”.
Is debris-fishing really efficient for cleaning up the oceans?
According to a publication by Jambeck et al., (Plastic waste inputs from land into the ocean), an estimated 4.8 to 12.7 million metric tons of plastic waste entered the oceans in 2010.
According to their own feasibility study [p. 441], The Ocean Cleanup (TOC) are hoping to “extract 70,320,000 kg (42 %) of garbage from the North Pacific Gyre in 10 years”. To put it into perspective: TOC are aiming at removing 70,320 metric tons in 10 years, or 7,032 metric tons per year. This constitutes only 0.06% to 0.15% of the 4.8 to 12.7 million tons marine plastic debris that was added to the ocean in 2010.
N.B.: TOC is using kilograms (kg) as a unit, a metric ton (MT) is 1,000 kg. And TOC are comparing their removal rate with the amount in the North Pacific Gyre, instead of actual annual influx of plastics waste, which in my opinion would be adequate. 
The projections of Jambeck et al. foresee that in the year 2025 an estimated 150 (one hundred and fifty) million tons of plastics will enter the oceans. The 7,000 tons per year TOC are therefore aiming at removing a mere 0.005% (zero point zero zero five percent) of that amount. And after 2025? Jambeck et al. are predicting that “We will not reach a global “peak waste” before 2100”.
Again: will plastics debris recovery make a difference in terms of quantities? The answer for me is no.
The diagram below puts into perspective the quantity removed by the TOC array over one year, compared to the influx of the top 20 polluting countries. The top five countries, China, Indonesia, Philippines, Vietnam and Sri Lanka, contribute to more than 90% of the pollution:
Most of the countries listed in the diagram above suffer from bad practices in waste management, which is the prime source of the plastics debris in the oceans.
Is ocean cleanup cost-efficient?
The TOC feasibility study states: “This means that in order for it to be profitable, a break-even cost of € 4.53 per kg (low: € 3.66, high: € 5.26) must be taken into account.” [p. 441]
It implies that “beach cleanups (€ 0.07-18.0), and […] the average direct costs to industry in the APEC region per kg per year (sic) (€ 6.51)” are more or less in the same range. Apart from the fact that € 0.07 is definitely not in the same range as the € 4.53 per kg as suggested by TOC, this comparison in my opinion is meaningless.
That being said, waste pickers segregating and selling recyclables in developing countries would be really happy if they were paid € 0.07 per kg for their plastics.
For what reason do I think the comparison with other beach cleaning and plastics-fishing activities is meaningless? Because what counts economically is the comparison to the real market value of plastics recycling material. And that is missing in the feasibility study.
The current market price for plastics (sorted by type, delivered and packaged) varies around or below 100 € per metric ton, or 0.1 € per kg. That means that the current value of the plastics recovered is approximately 2% of TOC’s break-even costs.
So, will it ever be economically viable? I think, it will not. I think, it will never hit the break-even point, it will always depend on donations.
Is it really worth while fishing for plastics debris on the high seas?
With thousands of kilometres to transport the debris by ship to land, where it needs to be washed and sorted. Applying improved waste management practices in the most notorious polluter countries would have a much greater effect.
The Ocean Cleanup is proposing to remove around 0.06% to 0.15% of the quantity that reached the oceans in 2010, at “a total cost of € 317,198,000 […]” over 10 years [feasibility study, p. 441]. That would be nearly 32 million Euros per year.
At an efficiency of 0.06% to 0.15% like TOC, the world would need one thousand TOC Arrays to cope with the waste influx of 2010, at annual cost of 32 billion Euros. Meaning 100,000 kilometres of booms, enough to span the equator two and a half times, or about a quarter of the distance to the moon.
In 2025, the proportion of waste collected compared to the influx will be reduced to a mere 0.007% (zero point zero zero seven percent, or one hundredth of a percent). Meaning that in order to remove all the influx of debris, in In 2025 we will need more than ten thousand ocean cleanup arrays, each with one hundred kilometres of booms.
The costs would be 32 billion Euros for that one year, and the total length of booms would be 2,000 km.
Fishing for debris in the oceans is David against Goliath, only this time David cannot win.
In my opinion, these undertakings miss the point completely. They are not only less than efficient, they will make close to no difference at all.
Is there an alternative?
The problem is mismanaged waste in coastal regions worldwide, the existing ocean debris is a symptom that will get worse if there is nothing done at the source. In 2025, 100 million tons of plastics debris will reach the oceans, and at 7,000 tons a year, debris fishing is not even remotely able to make a difference.
Even The Ocean Cleanup’s feasibility study [p. 441] states: “Finally, for this project to be truly successful in reducing the amount of plastics in the Great Pacific Garbage Patch, it is essential for the influx of new plastic pollution into the oceans to be radically reduced.” 
To quote Jambeck et al. again: “To achieve a 75% reduction in the mass of mismanaged plastic waste, waste management would have to be improved by 85% in the 35 top-ranked countries. This strategy would require substantial infrastructure investment primarily in low- and middle-income countries.”
And I agree wholeheartedly. If the source of ocean debris is not shut down, and waste management in the countries contributing to marine plastics debris is not improved drastically: Why should anybody invest a huge amount of money in a technology that has an insignificant impact on the overall situation, at a huge cost, and with a probably significant impact on marine life?
I am more than convinced that instead of spending more than 300 million Euros in ocean debris cleanup in the next ten years, it is more important to improve waste management in the countries mentioned above. Only this would have a measurable and more sustainable effect. Not only in terms of reducing ocean plastics pollution, but also by improving peoples’ lives in those countries.
A real life example
I have been working in Haiti for several months, in the Département of Grand’Anse, in the aftermath of typhoon Matthew, which had struck in October 2016. There is virtually no waste collection, people have no option other than either burning the waste in their back yard, or throwing it into ravines. From there, the frequent rainfalls wash away the waste, and it ends up in the sea. This is where ocean plastics debris comes from:
Currently, there is no more recycling of plastics in Grand’Anse. I spoke to recyclers in Port-au-Prince, and they confirmed that before the oil price dropped there was plastics recycling in that region, providing small but critical and additional income for hundreds of families. Due to the current low oil price, this livelihood is lost.
All of Grand’Anse produces an estimated 85,000 metric tons of waste annually. According to a study  the per capita waste production in Haiti is 0.5 kg per day. According to another source , approximately 9% of that waste is plastics, equalling roughly 7,700 metric tons per year.
Using the same semantic sleight of hand (or word, as it is) as The Ocean Cleanup, Grand’Anse produces an estimated 7,700,000 kg per year or 77,000,000 kg in 10 years. To compare: TOC is aiming at collecting “[…] 70,320,000 kg (42 %) of garbage from the North Pacific Gyre in 10 years” (TOC feasibility study, see quote above).
The population of Grand’Anse is producing already the same amount of, or rather more than the plastics waste that TOC hopes to salvage from the high seas. Even if we assume that only half, only 25% of that goes into the Caribbean sea, that would still account for roughly 50% of what TOC is hoping to recover. And TOC is calculating annual costs of nearly 32 million Euros for their Array.
With 1.5 million € each year, or 15 million Euros for 10 years, simple, efficient and effective improvement of waste management practices in all five countries contributing to 90% of the plastics debris would be possible. This would definitely have a greater effect than any floating debris-fishing contraption.
Why pay 4.53 Euros per kg to a high-tech company if millions of waste pickers around the world could do it so much more efficiently? The current price for plastics paid to the waste pickers in Haiti is € 0.07 per kg, and it is their livelihood. Improving their efficiency would increase the waste picker’s income, improve the lives of millions of the poorest people around the world and reduce the influx of plastics .
But to find funding for this kind of projects is difficult, because it wouldn’t be innovative, it would be “just” state-of-the art, everyday, just-normal common-sense waste management. According to Mr. Slat, it would be “uninspiring”.
I think that technical visionaries who can inspire others with big ideas are good for raising global awareness. Not less, but also, not more. Awards, honours and public attention, or millions of Euros in crowd and public funding, are no guarantee for a meaningful project. I am convinced that there are much better uses for that money. These projects in terms of real effect on cleaner oceans do not make any difference whatsoever.
To drive the point home: Without shutting down the source by improving waste management in the countries producing all the debris, any type of plastics debris fishing is an exercise in futility. And by reducing the sources, this project becomes obsolete, too.
Projects on land would help hundreds of thousands of people out of poverty, at the same time reducing environmental pollution and improve access to clean drinking water for millions. This of course would involve the development of a common set of policies in waste management, involving the national governments, the United Nations (UNDP, UNEP and other UN organisations) and of course (I)NGOs and the stakeholders.
It would make a huge difference, and I find this aspect highly inspiring.
Thank you very much for commenting and mentioning another aspect, Dr. Giadom, “cleaner cities” is the keyword:
If we, if donors – instead of paying TOC 31,700,000 € per year (or roughly 35,209,000 US$) – spent a dollar a working day per waste picker to improve their efficiency, we could lift the lives of approximately 140,000  waste pickers around the world above the poverty line, and achieve a better effect in controlling the source of the plastics debris.
The photos below are examples of what can be done on land as an alternative. Prevention is more important than remediation. Next to prevention comes segregation at the source.
[Click one of the photos to start the slide show, navigate clicking the arrows on the left and right.]
 Joaneson Lacour, Politique Nationale des Déchets solides en Haïti, Table Regionale de Coordination pour le Gran Sud, Port-Salut, 26 mai 2016 (presentation)
 Waste quantity assessment data from Cap-Haitien (Philippe, 2009)
 Note: Sub-chapter 2.6 is about modelling and does not mention this statement, you can only find it repeated in the Executive Summary on p. 33.
 data source: Jenna R. Jambeck, Roland Geyer, Chris Wilcox, Theodore R. Siegler, Miriam Perryman, Anthony Andrady, Ramani Narayan, Kara Lavender Law: Plastic waste inputs from land into the ocean, Science 347, 768 (2015);
data on MMT/year calculated by Thorsten Kallnischkies, derived from the figures from the authors’ article.
 assuming 250 working days per year and 1 US$ per working day per waste picker: US$ 35,209,000 ÷ US$ 250 = 140,836 waste pickers
 Using kg units instead on tons, or litres instead of m³ produces large figures, with small units. This is a popular method for us scientists and engineers to veer the attention away from the fact that we are operating with small quantities. Stage magicians do that, and it is entertaining. Do watch out when engineers and scientists do that, especially when they use both tons and kgs.
© Photos and diagram: Thorsten Kallnischkies, all rights reserved.