Anaerobic Digestion

Breaking Down Anaerobic Digestion

Anaerobic digestion is a biological process that is rapidly gaining traction across all sectors that create organic waste.

During anaerobic digestion, microorganisms break down organic matter releasing a combination of methane and carbon dioxide, known as “biogas”.

There are four main biological and chemical processes that occur in anaerobic digestion:

  1. Hydrolysis
  2. Acidogenesis
  3. Acetogenesis
  4. Methanogenesis

In hydrolysis, digestion breaks down insoluble organic polymers making them available for other bacteria. The acidogenic bacteria break down the matter producing hydrogen, organic acid, carbon dioxide and ammonia.

During acetogenesis, the bacteria convert the organic acids into acetic acid, more ammonia, hydrogen and carbon dioxide. Methanogens are then able to convert all of these into methane and carbon dioxide during the final stage.

Digesters require a steady stream of organic waste to sustain a continuous production of biogas; this makes operations with constant sources of waste ideal for digesters. When paired with the correct technology, AD can benefit both the operation and environment.

Examples of facilities that can benefit from AD include:

  • Wastewater treatment plants
  • Grocery stores
  • Composting facilities
  • Campuses
  • Dairies
  • Food processors
  • Rendering facilities
  • Landfills
  • Breweries

The U.S. currently has the potential to generate 11.7 million megawatt hours of electrical power from anaerobically digesting manure and food waste, according to the Innovation Center for U.S. Dairy®.

Approximately 82 percent of the United States’ current energy supply is derived from oil, gas and coal sources, according to the Institute for Energy Research. These fossil fuels continue to release significant amounts of carbon dioxide and are increasingly environmentally damaging to extract.

Simultaneous to the need for sustainable energy solutions, the United States is struggling with a waste management issue across virtually all sectors.

Biogas from anaerobic digestion provides an alternative to depending on unrenewable and polluting energy sources, while utilizing waste as a resource. When combusted, this biogas can provide renewable heat and electricity. Although varied between feedstocks, the average ton of organic material can produce ~3,000 ft3 of biogas and ~220 kWh electric power.

One of the most unique attributes of digester biogas compared to other renewables is its ability to be stored and converted to fuel.

The major benefits of biogas are:

  • Solves waste management issues while supplying renewable power, heat, cooling and fuel
  • Offsets carbon dioxide emissions
  •  Available all year round— 24/7
  • Is independent of the weather, therefore avoiding extreme fluctuations in supply, allowing it to provide base load power
  • Can be processed to CNG which can be stored and used as vehicle fuel

Through our highly engineered fermentation systems, BIOFerm™ Energy Systems technology enhances this process by providing ideal environmental conditions, resulting in the efficient production of top quality biogas from a variety of organic inputs.