Design Process 1:
Should we use the worms themselves or their enzymes in the trash can?
Design Process
Plan 1: We will use super worms and wax worms directly in our trashcans to degrade different kinds of plastics.
Limitation: During our research we found that one wax worm can eat 1.84 mg of plastic per day (it will take 100 worms 22 days to eat a plastic bag). At this rate it will take several days for a worm to degrade 1 plastic bottle, making it a very slow process. Also growing worms is a tedious process and we need to take additional precautions for the worms not to escape from the trashcan.
Plan 2: Hence the most effective method is to extract the enzymes from the bacteria living in the worms and use that to degrade plastic.
We divided the trashcan into several compartments, each with its own function. The shredder compartment will shred the plastic. We also found that the saliva of wax worms helps to oxidize the plastic, which speeds up the degradation process. Since we decided to use the degradation enzymes instead of using the worms themselves, we realized that adding an oxidation compartment to oxidize the plastic before the plastic moves into the degradation compartment to be degraded by the enzyme will be extremely helpful.
Design Process 2:
Should we use SAP sheets of sodium bicarbonate to dispose of the glycol?
Plan 1: We decided that the ethylene glycol generated after plastic degradation will be absorbed using a Super Absorbent Polymer (SAP) sheet and disposed off.
Limitations: If we use Super Absorbent Polymer, we will introduce more pollutants to the environment while disposing the SAP soaked in glycol. Both SAP and glycol are not good for the environment. This totally defeats the purpose of cleaning the environment of plastic while introducing another pollutant.
zophobas morio
SAP
SAP Sheets
Glycol
Plan 2: During research we found that when we mix sodium bicarbonate with ethylene glycol, it will release carbon dioxide, water and sodium acetate. Also we found that small amount of sodium acetate can be disposed in trash safely without any hazard as per OSHA. So, we decided to move ahead with sodium bicarbonate.
Design Process 3:
Should we add some accessories in the trash can for better functionality?
Solar Panels
Solar Panels: We will use electricity for operating the motor in the oxidation and degradation compartments for the pods to mix with the plastic and act on them. We decided to use solar panels to provide us with the electricity instead of power source (AC current) since solar energy is cleaner and more cost effective than using AC current or battery.
Weight Sensor: We wanted to make sure that correct amount of plastic is fed into the plastivore trashcan, so that the enzymes in the pods can work on it to have effective oxidation or degradation. So, we decided to use weight sensor in the trashcan to make sure that too much plastic is not passed into the oxidizing or degradation compartment at once.
Non-plastic Detector Sensor: We wanted to make sure that only plastic is being fed into the trashcan. If metals or glass is trashed, that can lead to malfunctioning of the trashcan. We decided to add a sensor to the receiver compartment which can detect any non-plastic material and alert the owner to remove it before processing the plastic through the trashcan