The Ocean Cleanup


The Ocean Cleanup is a non-government engineering environmental organization based in the Netherlands, that develops technology to extract plastic pollution from the oceans. After a couple of years of various tests they deployed their first full-scale prototype. It ran into difficulty after two months and was towed to Hawaii for inspection and repair. In June 2019, their second prototype system was deployed.
The organization conducts scientific research into oceanic plastic pollution. It was founded in 2013 by Boyan Slat, a Dutch-born inventor-entrepreneur of Croatian origin who serves as its CEO. It has conducted two expeditions to the North Pacific Gyre, and published scientific papers. The clean-up approach uses barriers in ocean gyres to scoop up marine debris as the barrier is pushed by wind and current. The project aims to launch a total of 60 such systems in the patch by 2021. They predict this capability could clean up 50% of the debris in the Great Pacific Garbage Patch in five years.
In late October 2019, TOC announced a new initiative, The Interceptor, to attack the trash problem closer to the source, with plans to prevent the 80% of ocean trash coming from 1000 rivers worldwide.

History

Slat proposed the cleanup project and supporting system in 2012. In October, Slat outlined the project in a TED-talk. The initial design consisted of long, floating barriers fixed to the seabed, attached to a central platform shaped like a manta ray for stability. The barriers would direct the floating plastic to the central platform, which would remove the plastic from the water. Slat did not specify the dimensions of this system in the talk.

2014 - revisions

In 2014, the design was revised, replacing the central platform with a tower detached from the floating barriers. This platform would collect the plastic using a conveyor belt. The floating barrier was proposed to be 100 km long. In 2015, this design won the London Design Museum Design of the Year, and the.

2015 - scale model tests

In 2015, scale model tests were conducted in controlled environments. Tests took place in wave pools at Deltares and MARIN. The purpose was to test the dynamics and load of the barrier, when exposed to currents and waves, and to gather data for continued computational modeling.

2016 - open sea tests

A 100-metre segment went through a test in the North Sea, off the coast of the Netherlands in the summer of 2016. The purpose was to test the endurance of the materials chosen and the connections between elements. The test indicated that conventional oil containment booms could not endure the harsh environments the system would face. They changed the floater material to a hard-walled HDPE pipe, which is flexible enough to follow the waves, and rigid enough to maintain its open U-shape. More prototypes were deployed to test component endurance.
On May 11, 2017, The Ocean Cleanup announced the next step is to test their new drifting system in the North Pacific in 2017.

2017

In May 2017, significant changes to the design were made:
The Ocean Cleanup performed more scale model tests in 2018. The sea anchors were removed because the wind moved the system faster than the plastic. The opening of the U would face the direction of travel, which would be achieved by having the underwater screen deeper in the middle of the system, creating more drag.
On September 9, 2018, System 001 deployed from San Francisco. The ship Maersk Launcher towed the system to a position 240 nautical miles off the coast, where it was put through a series of sea trials.
When the tests were complete, it was towed to the Great Pacific Garbage Patch for real-world duty. It arrived on October 16, 2018, and was deployed in operational configuration. System 001'' encountered difficulties retaining the plastic collected. The system collected debris, but soon lost it because the barrier traveled too slowly.
In November, the project attempted to widen the mouth of the U by 60-70m but failed. In late December, mechanical stress caused an 18-meter section to detach. Shortly thereafter, the rig began its journey to Hawaii for inspection and repair. During the two months of operation, the system had captured some 2,000 kg of plastic.

2019

In mid-January 2019, the Wilson system completed its 800-mile journey and arrived in Hilo Bay, Hawaii. Ocean Cleanup planned to return the repaired system to duty by summer. In mid-June, after four months of work, the revamped system was redeployed. This too failed. In August, the team announced that after trying multiple alternatives, a water-borne parachute attached to slow the boom and expanding the cork line used to hold the screen in place would be tested. In October it became clear that the new system successfully holds plastic, and even microplastics. The model is also more efficient and smaller, making offshore adjustments possible.

Design

The system uses passive floating structures localized in the ocean gyres, where marine debris tends to accumulate. These structures act as a containment boom. The boom drifts with the wind, waves and ocean currents to capture marine debris. A solid screen underneath the floating pipe catches subsurface debris. The system requires no external energy.
The first deployment, System 001, consisted of a long barrier with a wide skirt that hangs beneath it. It is made from HDPE, and consists of 50x12 m sections joined together. It was unmanned and incorporates solar-powered monitoring and navigation systems, including GPS, cameras, lanterns and AIS. The barrier and the screen mounting were produced in Austria by an Austrian supplier.
In 2019 a string of inflatable buoys was installed across the system's opening, to increase its speed. This edition used simpler connections between the barrier and skirt, eliminated stabilizing structures and reduced the barrier size by two-thirds.

Research

Oceanic expeditions

In August 2015, The Ocean Cleanup conducted its so-called Mega Expedition, in which a fleet of approximately 30 vessels, including lead ship R/V Ocean Starr, crossed the Great Pacific garbage patch and mapped an area of 3.5 million square kilometers. The expedition collected data on the size, concentration and total mass of the plastic in the patch. According to the organization, this expedition collected more data on oceanic plastic pollution than the last 40 years combined.
In September and October 2016, The Ocean Cleanup launched its Aerial Expedition, in which a C-130 Hercules aircraft conducted a series of aerial surveys of the Great Pacific garbage patch. The goal was specifically to quantify the amount of large debris, including ghosts nets in the patch. Slat stated that the crew saw a lot more debris than expected.
The project released an app called The Ocean Cleanup Survey App, which enables others to survey the ocean for plastic, and report their observations to The Ocean Cleanup.

Scientific findings

In February 2015, the research team published a study in Biogeosciences about the vertical distribution of plastic, based on samples collected in the North Atlantic Gyre. They found that the plastic concentration decreases exponentially with depth, with the highest concentration at the surface, and approaching zero just a few meters deeper. A follow-up paper was published in Scientific Reports in October 2016.
In June 2017, researchers published a paper in Nature Communications, with a model of the river plastic input into the ocean. Their model estimates that between 1.15 and 2.41 million metric tonnes of plastic enter the world's oceans every year, with 86% of the input stemming from rivers in Asia.
In December 2017, they published a paper in Environmental Science & Technology about pollutants in oceanic plastic, based upon data from the Mega Expedition. They found that 84% of their plastic samples had at least one persistent organic pollutant in them exceeding safe levels. Furthermore, they found 180 times more plastic than naturally occurring biomass on the surface in the Great Pacific Garbage Patch.
On March 22, 2018, The Ocean Cleanup published a paper in Scientific Reports, summarizing the combined findings from the Mega- and Aerial Expedition. They estimate that the Patch contains 1.8 trillion pieces of floating plastic, with a total mass of 79,000 metric tonnes. Microplastics make up 94% of the pieces, accounting for 8% of the mass. The study suggests that the amount of plastic in the patch increased exponentially since 1970.
In October 2019, when research revealed most ocean plastic pollution comes from Chinese cargo ships, an Ocean Cleanup spokesperson said: "Everyone talks about saving the oceans by stopping using plastic bags, straws and single use packaging. That's important, but when we head out on the ocean, that's not necessarily what we find."

Funding

The Ocean Cleanup is mainly funded by donations and sponsors. As of November 2019 it has made a little over $35 million from sponsors including Salesforce.com chief executive Marc Benioff, philanthropist Peter Thiel, Julius Baer Foundation and Royal DSM. The Ocean Cleanup raised over 2 million USD with the help of a crowdfunding campaign in 2014.

Criticism

Criticisms and doubts about method, feasibility, efficiency and return on investment have been raised in the scientific community about the project. These include:
In late October 2019, The Ocean Cleanup introduced its new river Interceptor initiative to help clean oceans by reducing trash pollution input closer to the source - rivers. Solar-powered Interceptor vessels use floating arms to direct floating waste into the collection conveyor, which dumps trash into dumpsters on a detachable barge below. When full, the collection stops until the barge is removed, emptied and returned to the Interceptor. The Interceptor project is similar to a smaller-scale local project called Mr. Trash Wheel developed in Maryland's Baltimore harbor. The first two Interceptor systems have been operating in Indonesia and Malaysia, with the next planned for Vietnam and the Dominican Republic. Contracts have been signed for Thailand, Honduras, Los Angeles County, expected to be deployed in 2020.

Recognition

The project and its founder have been recognized in many fora.