Six Senior Engineering students from the University of Vermont (UVM) took up IWD's challenge to design a replacement for undersink disposers that would help address the excessive amount of food waste that goes to landfills.
The process followed was similar to what any company would do: brainstorm, research, try ideas, do more research, more brainstorming and problem solving, build parts, deal with failures, build a prototype, have it fail the morning of the presentation, quickly adapt a new part, and present the project to an audience that includes the Governor of Vermont. The students did this on top of a full course load, spent their spring vacation working on the prototype and completed the entire project in nine months.
The students were in a two-semester course called Student Experience in Engineering Design (SEED), a "capstone" course that connects senior mechanical and electrical engineers with outside companies to produce a deliverable prototype. IWD served as advisors to the team and provided our workshop and sourcing resources to the team. We also contributed a few spare parts to the final product. However, the team made decisions and did the grunt work.
The SEED team first spent considerable time honing a Purpose Statement: "The purpose of this project is to develop a resource-efficient, residential waste management appliance that reduces the amount of recyclable, biodegradable material entering the waste stream."
After initial brainstorming sessions each member of the team designed a conceptual model. As they reviewed those first designs, they realized some of their first hoped-for processes were not going to be feasible. They could not incorporate a grease/water separator and they didn't have space to hold the final product long enough to create compost. For the first prototype the team used five primary focuses:
- Volume reduction of food waste
- Movement of the food waste
- De-watering of the food waste
- Heat to neutralize the food waste
- Limit the size to fit under a sink
A grinder, inspired by a grain crusher, provides volume reduction and is less reliant on water than a traditional disposal. A custom-designed auger provides movement of food waste upward, allowing waste water to drain separately. Food waste lands in an insulated bin where it is heated to a minimum of 140°F to sterilize and is aerated by components borrowed from a blender. Components from a compact household dehumidifier further dried the waste product in a closed system to minimize odors.
Professor Mike Rosen facilitates presentations to the affiliated manufacturers periodically during the two semesters and finishes off the year with an event complete with distinguished guests and full-blown demonstrations of the working products.
