top of page
This site was designed with the
.com
website builder. Create your website today.Start Now

Final Project Research Submission #2:

Pacific Ocean Cleanup Array

Plastic Input from Rivers
Majority of plastic debris that end up in the ocean are from river emissions. It is estimated that 1.15 - 2.41 million tons of plastic enter the oceans from rivers annualy. Top 20 rivers, that are responsible for 67% of plastic pollution from rivers, are located in Asia. 74% of emissions occur closer to summer months: May to October. 
Visualization of plastic input from rivers. Input is often correlated with population in the region. 
Out of 122 rivers, which contributed more than 90% of the plastic input: 103 rivers located in Asia, 8 in Africa, 8 in South and Central America, and 1 in Europe. This data is based on plastic debris with size of 0.5mm or more. 
Top 20 rivers that contribute 67% of plastic emisison into the oceans.
Alternative Plastic Removal Solutions
Drone Based Concepts:
This concept considered a use of underwater drones that collect plastic by sucking it in. The picture shows the concept more clearly.  
Drone cleaning plastic concept
Advantages:
​
  • Easy to deploy in zones with high concentration of plastic
  • Inexpensive to repair
  • Could capture smaller particles
  • Cheaper than a vessel based solution
  • Unmanned
Disadvantages:
​
  • Requires high speed of travel against currents, which is drains battery quickly
  • The battery limitations would attach a crew to constantly recharge it as well as travel to shores often
  • Unable to handle large debries such as nets 
  • Would require hundreds of units and  a lot of time to clean up the 
Vessel Based Concepts:
This method proposes a modifed vessel fitted with nets on the sides to catch the plastic. 
Advantages:
​
  • No need to develop new technologies
  • No need for extensive research
  • Second hand vessel could cut the costs
Disadvantages:
​
  • Requires too much time and too many units to clean the ocean - estimated to be 79, 000 years to clean the Great  Pacific Patch
  • Added fuel expenses
  • Added crew expenses
  • Unable to capture small fragments due to drag
  • Atmospheric emissions
  • Logistically impractical
Floating Islands:
Artificial platform floating in the ocean with the "skyscrapper" underwater. Such towers could filter the water as added function.
Floating Island
Advantages:
​
  • Plastic cleaning is secondary goal
Disadvantages:
​
  • Very high cost
Closer Look at Array Concept/ Feasibility
The array consists of a central unit, where the collected plastic is stored and where it collects. On both sides of the unit are inflatable barriers that catch and concentrate the plastic. The length of each barrier is over 50 kilometers 
Not to scale figure.
1) Catching - no net is used, just a barrier. As a result no harm to marine animals.
2) Concentration - the plastic is pushed by the currents into the center of the array.
3) Collecting - the plastic is filtered from the water by a series of filters and stored.
Collecting unit
Advantages:
 
  • The collecting unit is self sufficient - it is charged by solar and hydro energy. 
  • The estimated clean up time of the Pacific Great Patch is 5 to 10 years. This is due to the fact that the array utilizes currents, which bring plastic to it, instead of hunting for it like the ship and net method. 
  • Above mentioned points make the array the most cost effective methods.
  • On top of that, recyling the collecting plastic, partly covers a large part of the costs of the array.
  • Low carbon emission. 
  • No legal barriers in implementing the array: does not have a serious impact on vessel traffic, the collected plastic legally becomes the property of the cleanup company. 
The proposed barriers are similiar to the the booms used to contain oil spills: 
This kind of barrier is able to withstand ocean conditions. The booms are attached to a floating mooring system that hold its shape:
Mooring system, underwater rendering.
Costs:
​
In order to extract 70 million kilograms of plastic (42% of plastic in the Pacific) in 10 years the costs of the array would range between $260 million USD to $400 million USD. At the price point of plastic of $5 USD per kilogram of plastic means that only 70 million kilograms of plastic are collected the project would achieve a break-even point. 
References
Lebreton, L. C., Zwet, J. V., Damsteeg, J., Slat, B., Andrady, A., & Reisser, J. (2017). River plastic emissions to the world’s oceans. Nature Communications, 8, 15611. doi:10.1038/ncomms15611
​
Slat, B. (2014). How the oceans can clean themselves. Independently published book .
bottom of page