The Anaerobic Digester at MSU

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.

17 Replies to “The Anaerobic Digester at MSU”

  1. How is it possible to manufacture 300kW per hour? the is no such units. do you min 300kW? or 300kWhr in how much time?

  2. I am searching design principles of anaerobic digester , if we suppose have flow =36kg/day , percentage of organic materials 66.6% if we meet appropiate condition ,such as : temperature = 35C and mixing materials with velocity 50revelution per minute,Can we produce biogas with quantity 500L/day ?
    please answer me , i am waiting .

  3. Would this system be considered a Continuous stirred-tank reactor? or is there another name for this type of reactor?

  4. Why did you choose thermophillic over mesophillic? Was it an excess heat issue or gas production bennifit? To what percentage does the pretreatment of feed stock have on eliminating pathogens. Why is the cattle manure not treated, being that the effluent will be presumably used to grow cattle feed and alow for a completed cycle back to the cattle.
    Looks good though!

  5. Forgive my ignorance on the subject, but I must ask: the microorganisms produce CH4, then there is a bunch of hand-waiving saying it will generate electricity. How does the gas produce electricity, and more importantly, how is the production of CH4, which is a potent GHG, kept from entering the atmosphere during the process?

  6. Fantastic project!
    Don't waste
    waste. Turn waste into energy and other benefits…We should have more of these installed everywhere.

  7. I am working on a project in Deasert Hot Springs where we will be in need of alot of electricity. I would like to speak with you off line, is there a contact person and number available?

  8. You're still burning the fuel, though, and creating CO2. If you're running an internal combustion engine with it, you'll be producing more CO2 per MW of electricity, since there's no way you can match the thermal efficiency of a GE turbine. Your carbon foot print will still be larger. This project, however, still has a lot of merit (if it's well engineered). You'll be producing fertiliser for your agricultural department, and the plant will be powered only with your waste material, so it may save money and resources for your institution, and may cut down waste disposal costs.

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