September 18th, 2018 by Michael Barnard
Five years ago, Boyan Slat of the Netherlands had a vision. He saw the oceans cleaned of the plastic that was fouling them. He saw the inklings of a solution. Time passed. He received the United Nation’s highest environmental accolade for his vision. He did a TEDx Talk on his vision. He was chosen European of the Year by Reader’s Digest, among other interesting awards. He assembled a 60-person team of engineers.
And on September 9, 2018, his team launched a 2,000 ft / 600 meter long floating plastic tube with a ten-foot / 3 meter curtain underneath to undergo full-scale sea trials.
How likely is this to make a difference?
It has a much larger opportunity to be successful than I had originally thought. The go-to-study on this was done by Julia Reisser et al. The vertical distribution of buoyant plastics at sea: an observational study in the North Atlantic Gyre was published in 2015 in the journal Biogeosciences, which has a respectable impact factor of 3.7.
The key part of the abstract is this bit:
plastic concentrations drop exponentially with water depth, and decay rates decrease with increasing Beaufort number. Furthermore, smaller pieces presented lower rise velocities and were more susceptible to vertical transport. This resulted in higher depth decays of plastic mass concentration (milligrams/m^3) than numerical concentration (pieces/m^3).
This is well visualized in this chart from the study. The misapprehension I had been under since first hearing about the challenge was that the plastic was more evenly distributed throughout the water column. However, it’s actually concentrated, especially by mass, in the first 50 centimeters or 20 inches of the water.
Read more at source: https://cleantechnica.com/2018/09/18/ocean-plastic-cleanup-project-is-better-news-than-you-might-think/