The EPA states the following as environmental benefits of Anaerobic Digestion.
Last Updated: September 7th, 2017.
Diversion of Organics from Landfills
Organic materials can be separated from the municipal solid waste (MSW) stream and processed in an anaerobic digester.
These materials include:
Fats, oils and greases
Commercial food processing waste
Food scraps from residential properties
Food scraps from businesses (e.g., restaurants)
Keeping organic materials out of landfills is beneficial for the environment. If these materials are allowed to decay in landfills, methane and carbon dioxide can be released into the air and contribute to climate change.
The loss of valuable nutrients from our ecosystem is another downside to landfilling organic materials. When these materials are anaerobically digested, the resulting nutrients found in digestate can be used to feed and nourish the soil.
Renewable Energy Generation
When organic materials are anaerobically digested, biogas is created. Biogas is a renewable source of energy. Biogas can be used to power engines and generators to produce mechanical power, heat and/or electricity or a combination of these uses. It can also be compressed for vehicle fuel and after treatment can be used in similar applications as natural gas.
Soil Health Benefits
It is important to maintain soils that are healthy and productive to grow food to feed our local, national, and world populations.
Anaerobic digestion produces digestate, a nutrient-rich slurry. Digestate can be applied to agricultural land as a fertilizer and/or soil amendment to improve soil health. Digestate that is applied to land is subject to both state and federal regulations.
Technology exists to separate the digestate into solid and liquid components, which may be managed individually for reuse or further treatment. For example, the solid component may be heat-dried to produce fertilizer pellets or composted prior to land application.
The practice of land application of digestate can improve the health of our soils.
Soil benefits can include:
Improving plant growth
Alleviating soil compaction
Increasing organic matter content
Reducing soil erosion and nutrient runoff
Reducing the need to apply chemical fertilizers and pesticides
Helping increase the soil’s water retention ability, which reduces the need for irrigation
To ensure that land application is properly done, a nutrient and soil management plan is required in most states.
Methane Emissions Reduction
Methane is created when organic materials decompose in oxygen-free environments like landfills and manure lagoons. Anaerobic digestion systems capture methane and allow us to use that methane in a beneficial way.
Capturing methane is important because methane is a potent greenhouse gas that contributes to climate change if allowed to escape to the atmosphere.
Anaerobic digesters are used on livestock farms as part of an integrated manure management approach providing farmers with additional options.
These systems allow farmers a way to:
Reduce solids content
Minimize odors and pathogens
Reduce methane emissions from manure lagoons, stockpiles, and storage ponds
Generate products for use on the farm, such as animal bedding and high-quality fertilizer
In order to increase biogas production, livestock manure may also be combined or "co-digested" into anaerobic digesters along with other organic materials.
To read more from the EPA: Read More..