About

Overview:

After years of planning, the Office of Sustainability has initiated an on-site food scraps composting demonstration project to support the sustainability goals and research and education missions of Princeton University.

The demonstration project involves the Model 1000 composting system, an in-vessel aerobic digester (i.e. biodigester) developed by the company FOR Solutions. Located behind the FitzRandolph Observatory building, the biodigester has been operational since September 2018. In addition to converting a portion of the campus’s food scraps into a nutrient-rich soil amendment for campus grounds, the project will also support academic research around food scraps conversion – a topic of growing interest that can benefit from applied testing and performance assessment while federal and state targets increasingly call for drastic cuts in wasted food.

The System & Process:

The Model 1000 composting system uses a programmed rotation and aeration process to accelerate the aerobic decomposition of food scraps into finished compost in only five days.

[Graphic courtesy of FOR Solutions]

Every week, the University sends campus food scraps from Frist Campus Center and campus cafes to the biodigester where it is loaded into the system along with a bulking agent/carbon source (i.e. wood shavings) to produce nutrient-rich compost. This compost provides the University with a usable soil amendment for re-use on campus greens to enhance soil health.

Objectives:

The biodigester will support the University’s research and educational mission by providing an avenue of exploration through the Campus as Lab program, which works at the intersection of academics, operations and campus life to support applied learning and research around sustainability challenges.

The course, ENE 202: Designing Sustainable Systems, is an example of a course in which the biodigester can serve as a learning tool around waste management. Students may also conduct a research project for independent work using the biodigester. See the “Research Opportunities” section for ideas of related research questions.

In addition to supporting the academic mission of the University, the biodigester contributes to several campus sustainability impact priorities:

Resource  Reuse and Conservation: While the University already composts food scraps from all dining halls and Frist Campus Center through an independent organic waste management company, the biodigester will provide on-site food scraps recycling, thus further reducing greenhouse gas emissions and costs from hauling away food scraps. At the same time, the operation of the biodigester will launch an investigation into the potential for all campus dining venues to become zero-waste facilities, while serving as a model in decentralized food scraps management for other universities or municipalities. 

Healthy Ecosystems: When applied to soil, compost from the biodigester will support the presence of microorganisms and key fungi which provide a range of benefits such as increased soil water holding capacity, pollutant remediation, and greater plant access to nutrients. Healthy soil suppresses weeds, and healthy plants are less susceptible to diseases. Additionally, healthy soil and plants can contribute to reduced application and run-off of fossil-fuel based landscape inputs into the local environment. Thus the compost is expected to enhance the ecological health of the campus and surrounding region by promoting healthy soils and plants, and clean water and air.

Strengthened Sustainability Ethos: Guided tours, progress reports, and educational and operational opportunities around this on-campus demonstration project will increase visibility and engagement in campus sustainability efforts. The biodigester will foster a dialogue about greater contribution to responsible food scraps management, both on and off-campus.