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This topic contains 2 replies, has 3 voices, and was last updated by  E. Vinje 1 year, 9 months ago.

  • Starting a School Composting Project

    Created by Student gardener 123 on

    Hello, I represent a group of college students interested in starting a school composting project. Our Dining Commons currently produce 45 – 90 gallons of food waste per day and we are looking to reuse this material and turn it into dirt for our community garden. However, we have some challenges. First, our school is located in Indiana and subject to cold winters; will the composting process continue to work under these conditions? Building a tarp for rain protection shouldn’t be an issue but we really don’t know how big of a space we will need. Should we use bins? And, if so, how many? How labor intensive will the operation be? How much dirt will this produce? If someone could assist with these questions, we would greatly appreciate it!

    -Andrew

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  • #207774 Reply

    mhonnold
    Member

    ​Hey Andrew!

    Sounds like you’ve got a pretty big project on your hands! Is all the waste compostable material? ​Things like meat, milk, bones, grease, cheese, oil and fat must avoid the compost pile, or you risk contamination and attracting unwanted scavengers. It sounds like you’ve got lots of nitrogen-heavy additions ready for your pile, what about carbon additions? For a healthy heap, a C:N ratio of 25-30:1 must be met. Any more or less and the pile will slow down or stop decomposition completely. Dried leaves, straw, even paper make great carbon additions to balance out the nitrogen from the veggies. This may be your biggest hurdle to jump, working with your school recycling program or a local farm may create a beneficial relationship for both parties.
    The composting process may slow down a little in the winter, however, a healthy microbial culture in your pile will help to keep it up to temperature. I would suggest bins for collection, and a large concrete surface to house anywhere from 1-4 piles, depending on how big of a project you’d like to turn this into. It might be best to start smaller, while leaving space to grow the program. Collecting food waste and transporting it is gonna be the most labor intensive part, creating the pile and turning it is easy if you have access to a skidsteer. The compost you are creating is not a growing medium that can be planted directly into. It is more of a soil amendment, used to add organic matter and healthy microbes to your already existing soil.
    One pile will take anywhere from 6 months – 1 year to decompose into a usable product. Keep this in mind when planning your pile layout. How much compost is produced depends on how much input you have. 45-90 gallons is quite a variable range, I would suggest looking at monthly averages rather than daily. It might give you a better idea of how much carbon will have to be procured in order to achieve a proper ratio for decomposition.

    Hope this helps! :)

    #207801 Reply

    E. Vinje
    Keymaster

    Hi Andrew,

    What an awesome project to take on for your school! Although it may be a bit labor intensive it is definitely doable. I think that the easiest method will be to build a large static compost pile. If all goes well, you should only have to turn the pile three to four times and it should be usable in as quick as 6 months.

    First of all, you will need to be sure that the food waste you are collecting is in fact all compostable material. Perhaps talk to the dinning hall staff and let them know that the waste they are setting aside for you can not contain the following items: meat, dairy products, oils, onions, garlic, or citrus peels (don’t worry about a few slip ups – your pile will be large enough to handle it). Next, you will need to source an equal amount of carbon rich material, as the food waste takes care of the nitrogen input necessary to make good compost. These materials include bark, cardboard (free of dyes), leaves, newspaper and straw. Maybe you can gather some of these things from campus recycling or talk to a local farmer or tree service about straw or tree bark chips and leaves. The pile itself should be placed in a location with full sun year round. Composting will still occur in the winter but it will just slow down slightly. As long as your carbon to nitrogen ratio is optimal a compost pile does not require additional heat. Remember that before you start to build the pile, especially with this method of composting, you will need a good base layer of larger chunked material for aeration. Big wood chips are ideal.

    As for the space you will need, I would suggest at least a 25 square foot area for the pile to sit on. With this space and the amount of material you have to work with you can plan to build up to a 20 X 20 X 10 foot tall pile. You may also want to build two concrete bins to store your carbon rich and nitrogen rich inputs. The idea with a static pile is that you layer everything up and then pretty much just let it do its thing. It is the least labor intensive method with low fuel inputs as it only needs three or four good turns.This method also reduces the disruption of beneficial fungi and reduces CO2 loss and mineral and nutrient leaching due to frequent turning. Additionally, static composting requires little water and since food waste is already very moist you might not need to add any additional water to the pile. As long as water content remains around 55% you’re compost is doing good things. That being said, typically rain shelter is not required for protecting compost piles but in your case it would probably be a good idea.

    Ideal shrinkage of usable compost from all input materials should be about 1/3 of the original size of the pile. The amount you will produce depends on the amount of material you decide to build the pile with. I think that the most labor intensive aspect of this project will be gathering, sourcing and transporting the materials, but hopefully in six months you will have some great compost for use in your campus landscaping! Good luck, I really hope you can make it work!

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