The anaerobic digester at Michigan State University aims to reduce odor and emissions, from manure,
food waste and biosolids, create a closed cycle for recycling organic material, and
generate renewable energy.
The digester will use a mix of diary manure, dining hall food waste, bio solids (which
are nutrient rich organic materials), and other organic material from campus and greater
Lansing area as feedstock.
Once delivered, the food waste and biosolids will be treated (heated, pasteurized) at one
hundred and sixty degrees Fahrenheit for one hour to eliminate any potential pathogens.
The material will then be mixed with manure from the MSU Dairy Teaching and Research Center
and pumped into the digester.
The anaerobic digester is a sealed, airtight tank, which can hold 300,000 gallons.
Organic material will be heated to one hundred degrees Fahrenheit and will remain in the
digester for 20 to 30 days.
Inside the tank, mixers in the digester evenly distribute microorganisms.
These microorganisms break down the mixture producing biogas and nutrient rich digestate.
Bio gas, which is roughly 60% methane, is a form of renewable energy which will be used
to generate electricity.
The system will generate enough electricity to offset the MSU DTRC, around 300 kW per
hour, with enough left over to help power MSU.
The capturing and use of biogas will generate energy, shrink the carbon footprint of campus,
and improve sustainability.
What's left from the process is Digestate, the nutrient rich mixture that will be held
in the final, storage tank until it can be utilized.
Mixers in the storage tank will minimize settling for the potential 2.7 million gallons of digestate.
Any unused biogas can also be stored in the sealed headspace.
The nutrient rich digestate will be used to fertilize croplands or other biological treatment
processes to fuel research opportunities.
By utilizing anaerobic digestion technology, the organic materials from MSU will become
resources.
Renewable energy is created, while odors are reduced and emissions are eliminated.
This project is one example of how Michigan State University is actively working to improve
sustainability.