Michigan State University’s anaerobic digester is a system that not only reduces waste from MSU’s farms and dining halls but also creates energy for some campus buildings.
An anaerobic digester is a sealed tank, deprived of oxygen, in which organic waste is broken down at an elevated temperature. This allows the waste material to decompose quickly and produce methane that can be captured and used as fuel.
The methane, a renewable energy source, is used to produce electricity for some of the buildings on MSU’s South Campus. The system takes in waste sources such as dairy manure from the MSU Dairy Teaching and Research Center, food waste from several campus dining halls, fruit and vegetable waste from the Meijer Distribution Center in Lansing, and fats, oil and grease from local restaurants.
The approximately 17,000 tons of organic waste it utilizes each year will produce biogas used to generate over 2.8 million kWh of electricity per year—roughly equivalent to the energy used at Holmes Hall.
Even the leftover materials not used to produce methane are repurposed. The remaining solids are composted; the liquid is seasonally applied to campus land and nearby farms as carbon-rich fertilizer.
The south campus Anaerobic Digester project is located at the Dairy Teaching and Research Center on south campus in the Agriculture District.
The anaerobic digester system provides many benefits, including renewable energy, emissions reduction, landfill and wastewater diversion, and enhanced nutrient management on south campus, improving the environmental and economic sustainability of the farms.
It is also a part of several MSU classes, and won the 2014 Institutional Biogas Project of the Year award from the American Biogas Council.