Anaerobic digestion facts for kids
Anaerobic digestion is a collection of processes by which microorganisms break down biodegradable material in the absence of oxygen. The process is used for industrial or domestic purposes to manage waste or to produce fuels. Much of the fermentation used industrially to produce food and drink products, as well as home fermentation, uses anaerobic digestion.
Anaerobic digestion occurs naturally in some soils and in lake and oceanic basin sediments, where it is usually referred to as "anaerobic activity". This is the source of marsh gas methane as discovered by Alessandro Volta in 1776.
Anaerobic digestion is used as part of the process to treat biodegradable waste and sewage sludge. As part of an integrated waste management system, anaerobic digestion reduces the emission of landfill gas into the atmosphere.
Anaerobic digesters can also be fed with purpose-grown energy crops, such as maize.
Anaerobic digestion is widely used as a source of renewable energy. The process produces a biogas, consisting of methane, carbon dioxide, and traces of other ‘contaminant’ gases. This biogas can be used directly as fuel, in combined heat and power gas engines or upgraded to natural gas-quality biomethane. The nutrient-rich digestate also produced can be used as fertilizer.
Using anaerobic digestion technologies can help to reduce the emission of greenhouse gasses in a number of key ways:
- Replacement of fossil fuels
- Reducing or eliminating the energy footprint of waste treatment plants
- Reducing methane emission from landfills
- Displacing industrially-produced chemical fertilizers
- Reducing vehicle movements
- Reducing electrical grid transportation losses
With the re-use of waste as a resource and new technological approaches that have lowered capital costs, anaerobic digestion has in recent years received increased attention among governments in a number of countries, among these the United Kingdom (2011), Germany, Denmark (2011), and the United States.
Images for kids
-
Anaerobic digester system in Germany
-
Anaerobic Digestion Process Flow: All process flows are dependent on the balance of between proteins, carbs and fats.
-
Comparison of common biogas technologies
-
Design of a dry/solid-state anaerobic digestion (AD) biogas plant
-
Anaerobic lagoon and generators at the Cal Poly Dairy, United States
-
Schematic of an anaerobic digester as part of a sanitation system. It produces a digested slurry (digestate) that can be used as a fertilizer, and biogas that can be used for energy.
-
Biogas holder with lightning protection rods and backup gas flare
-
Biogas carrying pipes
-
Acidogenic anaerobic digestate
-
Gas street lamp
-
Imhoff tank
See also
In Spanish: Digestión anaeróbica para niños
