CDS Compost Pulper


In August of 2011, a compost pulper was installed in Stevenson Dining Hall to process post-consumer waste more efficiently. The Green EDGE Fund partially funded this project, partnering with the Senior Class Gift, Bon Appétit, and capital funding to cover the full cost.


Background premise:

Oberlin’s Campus Dining Services (CDS) has been composting pre-consumer waste since 2004, but found that the risks of bacterial contamination were too high to compost meat and post-consumer waste. The pulper grinds up this post-consumer food waste and extracts the water, allowing it to be composted with less risk of bacterial contamination. CDS sees the purchase of the pulper as a step towards eventual zero-waste dining facilities.


Cost-benefit estimation:

The compost pulper will reduce energy and water usage in Stevenson. The current disposal system for food waste uses large amounts of water and energy due to the need to run the garbage disposals in the dish rooms. The pulper is more water efficient, internally recycling the water used to convey food through the machine.


Additional benefits:

The 85 kg of food waste that the average person produces in a year breaks down into 1.8 kg of methane and 38.5 kg of carbon dioxide if sent to a landfill. Methane is 21 times more potent than carbon dioxide as a greenhouse gas, demonstrating the importance of finding alternative methods of food waste disposal. Using the compost as fertilizer will avoid the need to purchase conventional fertilizers and will sequester carbon in the soil.