We all know that there is a problem with plastic trash in our oceans. It floats around in the currents until it crashes ashore on scattered islands around the world. Unfortunately these islands are not always inhabited, so the trash lays in the sun slowly degrading until the next storm rolls through pulling all of it into the currents once again.
My plan is a two part system. Part one is the “Shake n Bake” setup. Basically it will be a shore based machine that relies upon solar thermal energy to melt down a variety of plastics and excrete a semi-compressed block shape. The reason for it’s name is that the process is to be as hands off as possible so as the plastic is in the hopper getting warm enough to melt, it will be slowly shaken to ensure a constant feed through the system. Since it is already collecting heat, there will be small pipes with pistons at various distances along the length. As the sun heats the air in the pipe, the piston will rise until the air escapes, putting a small shake into the system. Because it will be placed, unaccompanied, on remote islands this machine will be as bullet proof as possible. No electric motors, no electronics, just heat collected with mirrors and gravity fed into a clear tube filled with trash and at an angle so that the feed slowly drops the plastic into the storage area in a brick like shape. It will be as far from the shore as possible to protect it from storms, but close enough that people will put the trash in it.
Now step two is very important. It will require the aforementioned people. They will be sailing through, or they will be locals from nearby islands, or someone that feels the need to clean islands far from anywhere. As trash collects on islands people will arrive on an irregular basis and spend some time gathering up all the trash they can find. Perhaps this won’t be much and they could take a bag or two with them, but I doubt that would really be the case since boats have very little storage space for trash. So instead, they will take all that trash and fill the Shake n Bake with that trash. Then they can take the compressed bricks that came from prior trash collectors. Much easier to handle and transport.
I think the process would take anywhere from weeks to months to fully melt plastic into a brick shape and clear a hopper. A more complex system could do it faster, but then it would require more maintenance. Also, with a slower and lower temperature there would be fewer VOCs released into the air so it wouldn’t contributing to air pollution. This system would need hundreds or thousands of these machines around the oceans, but I think it would be the best way to slowly clear the existing plastic from the seas.-- unhelpful_fool, Sep 01 2019 Interesting, but how do you keep the non-plastic trash out of it? Also, not all plastic can be remelted. Much of it is thermoset.-- RayfordSteele, Sep 01 2019 Melted might be too extreme, moldable would be more likely. The idea isn't to make it re-usable but to make it smaller for transport.
As for non-plastic trash, that comes down to the people involved. Hopefully they aren't just throwing everything in there willy-nilly. Though, even if they are then it wouldn't be so bad. It's still just trash bricks.-- unhelpful_fool, Sep 01 2019 random, halfbakery