Nova Analytical Systems: #121 - Boyan Slat’s Ocean Clean-up Idea

Gyres are large systems of rotating ocean currents.

There are five major oceanic gyre systems on earth:

Indian Ocean Gyre

North Atlantic Gyre

North Pacific Gyre

South Atlantic Gyre

South Pacific Gyre

There are also several large floating garbage patches that are blighting this world’s oceans. The debris consists mainly of plastic particles, packaging, and containers of various sizes. Most of the garbage originates from land-based human activities and is washed out to the ocean by rivers and other flowing water-ways. Much of the debris eventually accumulates in the gyres mentioned above.

This problem has always annoyed me immensely because humankind has expended enormous amounts of time, energy, technology, and money extracting riches from the world’s oceans. For example, large fishing vessels roam the seas capturing marine life in giant nets. However, using the same or similar technology to clean up our oceanic garbage patches has always been deemed financially or technically prohibitive. The excuses always seem to sound hollow when you think about all of the ways that we can capably extract things from the water.

An ocean clean-up idea originating in 2011 from two students named Boyan Slat and Tan Nguyen offers some potential feasibility. Although the feasibility studies have not been completed, it is an idea that will at the very least stimulate good discussion and general awareness of this problem. One reason why awareness of this problem is low is that there are few visual images available. The garbage is spread out over millions of square kilometers and is not striking in terms of photographic imagery. Of course, there are many images and examples of shoreline pollution as shown above.

The clean-up concept consists of large anchored booms that can be placed in the radial path of the gyre current flows. The booms are arranged in a “V” shape which will funnel the floating debris into a collection platform. The gyres are very large, the general speed is low, and the collecting action is primarily at the surface of the water. It is therefore unlikely that marine life even down to the plankton level will be extracted or harmed along with the debris.

Feasibility studies are underway and they are making good progress on some preliminary results that look promising. A team of engineers, modelers, external experts, and students are in the process of testing some of the initial assumptions that were made. They are advising optimistic caution until more results are obtained.

The oceanic garbage issue is a kind of distributed waste stream problem that we all share collective responsibility for. The millions of candy wrappers and plastic water bottles shown on the shoreline above - where do they all come from? It isn't a single traceable point source. These items emerge into the environment every time a person tosses a piece of garbage on the ground or in the water without thinking about where it will end up. Holding on to the garbage for another few minutes until we can put it into a recycling bin or a garbage can, will at least help direct it into a treatable waste stream and keep it out of the immediate natural environment.

That would make Boyan Slat's idea unnecessary. I'm sure he wouldn't mind.

Edit Sept 2014: We have since done an update to this post here.