1. Biogas Digester
Jeff Rohrer
APES
March 19, 2012

2. How it works? Anaerobic digestion- absence of oxygen, aka fermentation
Organic waste is put in a air tight chamber to keep oxygen from entering
Plant, animal and fecal matter typical
Methane, Carbon dioxide, Hydrogen sulphide formed

3. Advantages/Disadvantages
Lessen global climate change
NO2 changes into CO less effect on climate
Reduces waste
Rural creation of reusable energy, higher S of L
Saves money, resources
Not as clean as natural gas
Methane has greater effect on climate change
Contamitive gases can hurt engines
Limited production, not controllable

4. Environmental Impacts
Methane is 20 times more potent of a GHG than CO2
Release VOCs contributing to photochemical smog
Methane CH4 50–75, Carbon dioxide CO2 25–50, Nitrogen N2 0–10, Hydrogen H2 ,0–1 Hydrogen sulfide H2S 0–3 ,Oxygen O2 0–0

5. Where it is used? What does it replace?
Typically used for cooking, electricity generation and heating
Can be cleaned and brought up to natural gas standards when it becomes biomethane
Can replace up to 17% of vehicle fuel
Used all over the world, especially in rural farming areas such as Germany (largest producer)
Small scale digesters, USA (1% of natural gas use), UK, China

6. Future Biogas transportation Biogas train in Sweden since 2006
Biogas buses used in Europe
Matter is compressed and used in transportation
Injection into the natural gas grid