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Mary Scher, Katie Davis, Peter Berdo, Amani Jones
What is Composting?
What is Composting?
Composting is the decomposition of organic matter by microorganisms in a managed, aerobic environment. Microorganisms feed on carbon and nitrogen from the materials to grow and reproduce, water to digest, and oxygen to breathe. This results in compost - a natural fertilizer that boosts soil health and stability. Composting can be done in a container, such as the wooden structure at the Sustainable Agriculture Project, or in a backyard pile. It is a rather hands-off process, and just needs disturbance every once in awhile, to increase aeration and speed up the decomposition.
Composting's Purpose
Composting is a sustainable alternative to trashing food scraps and biodegradable waste. In an enclosed landfill environment, organic matter cannot properly decompose and does not return to the soil. Cold composting is a cheap, accessible, and beginner-friendly process. It has multiple benefits for plant and soil health, and is environmentally sound because it creates a circular process of growth to waste, and waste to growth.
Our Mission
Our Mission
We strive to improve the cold composting conditions at the SAP to streamline efficiency of compost production and increase ease of access for staff members. While doing this, we are committed to our team ideals of sustainability, efficacy, and longevity.
Background Research
Background Research
The Ideal Composting Environment
The Ideal Composting Environment
Regular turning for aeration
Proper ventilation to release CO2
Shredding or chopping large materials
Carbon to nitrogen ratio (C:N): 25-30:1
Ideal moisture content: 50%-60%
Ideal temperature: 50-70 degrees F
pH: 6.0-8.0
Phases of Composting
Phases of Composting
Mesophilic Phase (hot phase)
Microorganism activity cause increased temperatures and pH levels to drop
Thermophilic and Hygienization Phase (curing phase)
Thermophilic microorganisms that can handle higher temperatures take over. They are responsible for breaking down complex materials.
Mesophilic Phase II (cooling phase)
Temperatures drop to normal, pH is slightly alkaline, funghi becomes visible
Maturation Phase
Carbonaceous compounds condense and polymerization takes place.
System Evaluation
System Evaluation
Testing:
From start to end, it would take about a year for waste to fully decompose
It was difficult to move the wood panels of the compost bin after it rained due to the swelling of the wood
Because there is only wooden panels in the front, it is difficult to take the compost from the backside of the bin
Open top to easily add organic matter
There is no turning of the organic matter in the bin, but rather more matter is just added to the top
Observations:
Low level of disturbance makes the decomposition process of slow and inconsistant throughout
Having only one side of access reduces the amount of compost you can actually obtain from the bin
The swelling of the wood renders the panels immobile at some times, making the compost inaccessable
Having wooden panels rather than a door makes it more difficult to access the compost
Having an open top may allow animals or inorganic matter to get into the bin
Because there is no turning of the compost, it takes a much longer time for the organic matter to break down
What's Working Well & What's Not
What's Working Well & What's Not
What's Working:
Uses the natural process of organic matter breaking down
Composting process works well with minimum human effort needed
Made out of organic material
Mesh sides are effective at aeration
What's Not Working:
Wood swells when wet, causing problems with the structure and extracting compost
Having to take boards off one at a time makes for a bad door system.
hard to access compost at the bottom of the pile
Only one access point
The wood material made to build this bin is cheap and reliable. It is also environmentally friendly
Here we can see that it requires somebody to move more than four boards to be able to access the bottom of the bin
Perhaps the hardest spot to reach in the bin is the bottom, on the other side than the door. How can we access this spot?
The boards often get dirt stuck in between each other and the slots for them. How can we develop a better mechanism that keeps dirt contained?
Recommendations
Recommendations
The basic structure of the bin is effective, we would absolutely keep the sides mesh and a basic wooden structure. What needs the most change is how to get access to the bottom of the box. This requires a different door structure.
Door Material
Door Material
In order to avoid swelling and extra labor, replacing the wood panels with a metal sheet door would be the simplest way to combat this issue. Adding a handle too would allow for easy opening of the structure
Door structure and hinges
Door structure and hinges
To get access to the bottom, we would like to have a door with hinges, preferably on both sides of the bin. This will allow access to opposite sides of the compost.
Conclusion
Conclusion
Composting is a sustainable and easy way to discard of food scraps and biodegradable material. At a small scale farm operation like the SAP, it cuts costs by producing a natural, rich fertilizer that can be used to increase soil fertility, stability, and overall health. Having an easily accessible and efficient cold compost bin structure is essential to farm processes. Our suggestions for a new composting bin will assure compost quality, ease of access, and longevity of the bin in an outdoor environment.
Sources Cited
Sources Cited
compost producers. University of Wisconsin–Madison, Center for Integrated Agricultural Systems. https://www.eawag.ch/fileadmin/Domain1/Abteilungen/sandec/E-Learning/Moocs/Solid_Waste/W3/art_science_composting_Cooperband_2002.pdf
EPA. (2018, October 16). Composting at home. US EPA. https://www.epa.gov/recycle/composting-home
Meena, A. L., Karwal, M., Dutta, D., & Mishra, R. P. (2021). Composting: Phases and factors responsible for efficient and improved composting (Article ID 10028). Agriculture and Food: E-Newsletter, 1, 85–90.
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