Compost Tumbler

The compost tumbler is a dual chamber continuous system. One chamber is where greens and browns are added, and the other is for curing and storing compost. If consistently used, this system can always be producing and yielding compost. 

System Details

While the compost tumbler is an unofficial contestant in the compost engineering challenge, it serves as a benchmark by which the other systems can be compared to. The tumbler is already an easy and practical way for a household to create compost, so having the tumbler challenges students to design and create a system that may make more sense for a typical household. Students may strive to create a system that trumps the compost tumbler in any of the following criteria and more: affordability, sturdiness, ease of use, holding capacity, use of sustainable materials. 

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The compost tumbler is the only system that is not fed with food scraps from New Leaf. Instead, it is fed with scraps generated at home that are brought to the garden, whether it be from members of the compost maintenance crew or from residents of the nearby community. With this being the case, the amount fed to the system is never the same. After every feeding and again after a couple of days, the system is spun about five times. 

System Takeaways

We learned that this system does not do well with being feeding at the 8:1 proportion of food scraps and sawdust. The system had too much moisture which was leaking from the bottom and it began to stink. We began to feed the system at a 1:1 proportion instead which improved the system's moisture levels.

The compost maintenance crew suggest starting the system with some finished compost or manure so that there is already an established microbiome present. Having this initial layer would also allow you to freely add greens without concern of the system becoming too wet.