Housing & Dining Services invested in a state of the art, fully-automated composting system called the Earth Flow. This enclosed, 30-yard capacity compost bin is located on the CSU Foothills Campus (three miles west of main campus). Pre-consumer food waste from CSU Dining Centers is composted in the Earth Flow. On average, the Earth Flow composter diverts 300,000 pounds of food waste from the landfill each year. The compost produced is used by the student farm, community non-profit organizations and as soil amendments for new construction at CSU.
Dining Center Pulpers
- Ram’s Horn, Braiden, and Durrell Center Dining Centers have pulpers in their kitchens, which mix all the food and paper waste with water, and then grind up the material. This slurry is then taken by pipe to a centrifuge, which removes excess water and recycles it through the system. The pulped organic waste is emptied into collection containers and composted through the Windrow compost system.
- The pulpers have helped reduce the waste stream volume by 70 percent and water consumption by 80 percent in the dining centers.
Earth Flow Living Lab
- The Earth Flow in-vessel composting system, located on the CSU Foothills Campus, accepts 2,000 pounds of material per day.
- The system operates as a living lab with student interns from Soil & Crop Sciences loading materials, taking measurements, and making recommendations for recipe and operational improvements. A faculty adviser in the College of Agriculture serves as a member of the Compost Team and selects the intern each semester. The Compost Operator provides hands-on instruction on site and the Assistant Director of Sustainability for Housing & Dining Services supervises the interns.
- Organic waste is loaded into one end of the vessel by placing the collection container on an automated tipper. Every time food waste is added, bulking material like straw, wood chips, and horse manure from the Equine Center is added at a 1:2 ratio.
- Material is composted for about three weeks inside the bin. Finished compost is discharged through an end door of the vessel. The compost is piled on site to cure for at least 3-4 weeks before being used in landscaping projects on campus.
Windrow Composting Partnership
- In 2017, Housing and Dining Services partnered with CSU facilities management to compost all pulped food waste from the Dining Centers in their windrow composting facility.
- This program composts HDS pulped food waste as well as food waste from the LSC, stadium, and academic departments. The HDS Earth Flow system runs side by side with the windrow facility. The funds to launch the windrow operation were provided by the University Facility Fee Advisory Board.
- Over 3 million pounds of food waste had been composted through the in-vessel composter and windrow system since their conception.