This week our shredder arrived! The shredder arrived on Wednesday around noon, and was packaged in wood slabs that were nailed together. We used crowbars and other tools to pry the shredder from the packaging. Once opened, we noticed the cord to plug the shredder into an outlet had no plug. So, we asked Michael Moore for help, who is the head of the Lehigh woodshop in the C3 building. He helped us to find the correct plug we’d need, judging by the voltage, amp, and phase of the motor. He gifted us the supplies needed to attach a plug, and we were able to install this onto the end of the cord. Once this was done, we had to wheel the shredder outside to the outlet on the side of the C3 building. This is the only outlet that would be able to handle the shredder’s needs. However, the shredder was kept in place currently by pieces of metal that were bolted into the base below the shredder. So, tools had to be used to remove the bolts, and allow the shredder to be wheeled outside. The shredder was placed under an overhang attached to C3 just outside of the woodshop, so that it can be protected from rain. We then plugged the shredder into the outlet and it successfully turned on.
We ran into a little bit of a problem when trying to test the shredder and its capabilities. Our shredder worked with PET, just took a little longer than anticipated but when we first tested sachets it got stuck because of a plastic grocery bag. This made us realize it cannot break down soft plastics. After that realization and trying to figure the machine out on Wednesday we decided to go back to the drawing board to think about possible solutions. On Thursday we did more testing which led us to finding that we need to put the sachet plastic through the machine twice in order to get it into the size necessary. This took a lot longer than anticipated so our next step is to sharpen the blades on Friday and see if that makes a difference. If not, it might be something to do with the voltage. These are things we want to discuss with Micheal Moore from the woodshop with and if he has any ideas of how to make the shredder faster and more efficient. Our other option we have been discussing is replacing the blades with smaller blades since the blades in our shredder are larger than anticipated, which might be why it shreds much slower than we had originally thought.
Another thing we have been focused on this week is the post-consumer plastic itself. We realized that we are not getting an influx of enough plastic to do 96 rounds of testing, even with the third collection bin. We contacted many lehigh people, including the office of sustainability, facilities, and the director of custodial affairs, Dan O’Brien, in regards to getting access to lehgigh’s recycling and being able to take some of their plastic. Dan said he can bring us 1-2 bags of PET and HDPE plastic in the next few days.
Another issue with the plastic is the issue of LDPE and HDPE bags. Grocery bags are often made of HDPE, and many plastic bags that are clear are LDPE. They are both polyethylene, but have different melting points, so should not be recycled together. However, our buyer, sentinel upcycling, says that these can be mixed together, or not, it is up to us. We have decided to keep them separate, at least for the washing trials. The other problem with plastic film like plastic bags is that they often do not have marking indicating the number or type of plastic they are.
On Friday of last week, we met with Professor Gabrielle String from the Department of Environmental Engineering on zoom to discuss water filtration methods. She was EXTREMELY helpful, and was able to provide us with lots of information during our meeting. She told us that collecting rainwater is a valid method, but in doing so, we’d have to wait until after the first rainfall to begin collecting rainwater. The “First Flush” as it is called essentially has a lot of dirt and sticks, and so you don’t collect this water. However, the following storms bring clean water, meaning you can simply collect this rainwater and use it for washing without even needing to perform any filtration techniques. She also told us of various different methods that can be used to reuse rainwater during washing. Using alums, screening, and sand filtration are just a few of the techniques that Prof. String went over with us, with each having their upsides and downsides. Finally, Professor String was able to help us come up with a method for measuring the “cleanliness” of plastic. We told Professor String of our idea to use ImageJ. She said our idea could work, but she had a better idea. She introduced us to the idea of turbidity, which is essentially the cloudiness of a liquid. She told us about instruments used to measure turbidity, and that there are two main types: turbidity tubes and turbidimeters. Turbidity tubes are very cheap and provide relatively accurate measurements, while also being used mainly for fieldwork. Turbidimeters on the other hand are very expensive, but are extremely accurate (to two decimal places) and are used in lab settings. Professor String agreed to let us gain access to a turbidimeter within the next two weeks for our testing.
When we weren’t working on doing actual shredding, we were focused on doing miscellaneous, smaller activities that still needed to be done. We began to set up the outline of our future research paper, and were able to make a structured table of contents that can help guide our writing. We then began to use our previous research to start writing the introduction and method sections of our research paper. We started identifying and sorting through our collected plastic. We were able to order a turbidity tube. Although we are going to be gaining access to a turbidimeter, the turbidity tube can be brought with us to the Philippines to perform fieldwork, and gain accurate measurements at our research facility. A log on Microsoft Excel was also created to help organize any data that we may obtain from our washing tests which we hope to begin next week.
On Friday, we tested the shredder even more, and noticed that despite crumbling up the PET bottles even more, the shredder would successfully cut the plastic, but into larger pieces. Even putting the plastic through a second time didn’t yield any smaller pieces. We came across a professor at the University of South Florida by the name of Thomas H. Culhane that specializes in eco-friendly research, and has a youtube video posted using our exact shredder. When he put PET bottles into his shredder, the shredder was able to successfully turn them into small pieces of shredded plastic. So, we decided to send him an email, asking some questions concerning how he uses the shredder, and what might be the issue with ours. We also asked him if he ever tested his machine with sachet plastic.
Image 1: Picture of our new shredder
Image 2: Work being done to the cord to add a plug to the end
Image 3: Shredded sachet plastic
Image 4: Shredded PET; notice how the pieces are still too large