Pedal Powered Plastic Shredder
The Design Challenge
In 2018, the global plastic waste per annum was at about 380 million tonnes. This trend of an increase in plastic waste seems like it has no intention of stopping, even more so during the ongoing pandemic where the use of disposable plastics is on the rise. At this point, we all already know the negative consequences that plastic pollution has on the environment and ourselves, making the need for more plastic recycling globally that much more imminent.
In developed countries plastic recycling isn’t much of an issue as they have the required infrastructure to make plastic recycling work on a national level, with trash-sorting and industrial recycling plants to speed up the process. However, in developing nations such as Kenya, this tends to be quite the challenge.
Although larger cities such as Nairobi already have some plastic recycling companies, rural locations are in dire need of local recycling solutions, which is where my project comes in. My design challenge is to design and create a plastic shredder in need of minimal infrastructure (although the recycling part becomes trickier in these rural locations.)
Summary of Research
In short, there are already multiple plastic shredder designs and types out there. Precious Plastic is an excellent source for these, but my final design is more a mix of multiple designs. One example is the hand-cranked shredder, as seen below.
Although this is probably the most off-grid option, requiring no electricity, it is by far the hardest to operate consistently as you constantly have to have somebody cranking if you want to shred plastic. Besides this, having a plastic shredder which requires no electricity isn’t that useful as the shredded plastic still needs to be recycled or transported to somewhere where it needs to be recycled to be turned into products. These can then be sold and used so it doesn’t end up as plastic pollution again. Besides this, getting an income from recycling seems like a great incentive to get people to start recycling, especially in low-income countries/areas.
Another design is a pedal-powered shredder. This essentially means you attach a similar mechanism as seen above to a bike with chains, allowing the physical effort you have to put into the shredding to become that much easier.
I find this to already be an improvement compared to the first design, as cycling requires less effort than the cranking mechanism does. Besides this, it does not require any electricity (as the first design) and it helps transport whoever is using the bicycle from place to place (which can help a lot in low-income countries, as there is economic theory behind how much mobility can help increase income and the quality of life.) The bike can also easily be put on a small stand if you just want to shred plastic while staying one place.
Then there’s the hand-drill powered shredder. This replaces the hand crank with an electric drill instead.
Although this eliminates the physical effort you have to put into the other ones, it does require more of an infrastructure, as a cheap cordless drill requires charging after 2-3 hours of use. This design wouldn’t work in the most rural areas, but as some infrastructure is required to recycle the plastic into products anyways, this isn’t much of an issue.
The design best fit for my design challenge has to be the bicycle shredder. There’s two different designs I consider for this. One is the one which was presented earlier, where its just the shredder on a bicycle:
The second one takes just the gearing system of a bicycle to allow to make a compact shredder which can be used by somebody sitting at a desk while they work. This would help to increase efficiency, as there doesn’t have to be one dedicated person to always bike, but instead, people can work on other things while also still shredding plastic.
Although my last adapted design is the most versatile, the bicycle also has the benefit of the added mobility. Although the bike design is probably the harder one to manufacture, it still is probably the best design to use for a rural Kenyan context.