What is anaerobic digestion?
Anaerobic digestion, sometimes referred to as “AD,” is a natural, biological process that breaks down organic matter without oxygen. Watch our video to learn about the process of anaerobic digestion and the benefits the facility would provide.
The following video explains how organic waste collected from homes, schools, and businesses would be brought to the facility, shredded, and loaded into a digestion tank. In the tanks, microorganisms would work to break the materials into two products:
- Biogas, which can replace fossil fuels for heating or be converted into a vehicle fuel that has the lowest carbon footprint of any vehicle fuel.
- Digestate, which is separated into liquids that can be used to replace fossil-fuel-based fertilizers and solids that become a nutrient-rich compost to help plants grow.
The Hennepin County Anaerobic Digestion Facility and Eco-Center video also shares our vision to establish an Eco Center that provides educational experiences, houses a green jobs learning center, includes an on-site urban farm and greenhouses, and delivers healthy food to our hunger relief partners. These strategies would help advance our climate action, zero waste, and healthy community goals.
Infrastructure development needs to keep pace with organics collection programs
Minnesota law requires metro counties achieve a 75% recycling rate by 2030. Waste sort studies continue to show that organic materials are the largest proportion of our trash — about 30%. Organics recycling is our biggest opportunity to reduce our trash.
- Organics recycling continues to increase due to the recent Hennepin County requirements for certain businesses to recycle organics. There are also requirements for cities to offer organics recycling for residents by January 1, 2022.
- The metro area is served by only two organics composting sites that are at or near capacity.
- Anaerobic digestion provides an opportunity to expand and diversify local organics infrastructure.
Anaerobic digestion is a higher and better use of material
- The EPA’s food waste hierarchy prioritizes anaerobic digestion over composting.
- AD transforms organic waste into two main products: 1) biogas, an energy source, and 2) digestate, a nutrient-rich fertilizer.
- Biogas from AD can displace dirty fossil fuels for heating and electricity generation. It can also be converted into biofuels for vehicles. The digestate can replace fossil fuel-based fertilizers.
Action on organics recycling is needed to meet our climate goals
- Food and organic material produces methane when it decomposes in landfills. Methane creates a warming effect 84 times greater than carbon dioxide over a 20-year period. Climate experts rank reducing methane from landfills as a top strategy for rapidly slashing greenhouse gas emissions.
- Diverting more organics from the trash through AD is one of the county’s foundational strategies in the Climate Action Plan to achieve net zero emissions by 2050.
- Methane created and captured from the controlled process of anaerobic digestion reduces greenhouse gas emissions effectively and creates beneficial products, such as renewable natural gas, fertilizer and compost.
- The proposed site's close proximity to the county's Brooklyn Park Transfer Station will also reduce emissions from transporting the material to composting sites and help reduce the cost of organics recycling by providing the opportunity to efficiently collect and process organics.