Biodigester :
What is a Biodigester?
• A device that mimics the natural decay process of organic matter
• Biogas is produced from anaerobic decay (decay that occurs without oxygen)
• A devise that give us water treatment , gas and fertilizers .
Objectives
• Create a source of fuel for cooking; etc.
• Provide a fertilizer from the digested waste; and get good water for the agriculture
• Improve health conditions by isolating wastes in a sealed container to reduce airborne pathogens from raw manure.
Biogas: Green Energy
- 50-70% methane;
- 30-40% carbon dioxide;
- Insignificant amounts of oxygen and hydrogen sulfide (H2S).
- Biogas burns without soot or ash being produced
- Methane is a combustible gas
- Biogas will be used to generate energy
Design Advantages
- Reduction in scum accumulation
- Temperature Control
- Ease of operation
- Durable
- Small footprint
- Low cost
- good water
What Type of Waste Produces Biogas?
• Any organic waste can produce biogas
• Human, manure, fruit and vegetable waste
What Type of Waste Does NOT Produces Biogas?
• Fiber rich waste such as wood, leaves, etc. are difficult to digest
• Heavy metals
• Inorganic materials in high concentration (Nitrate, Sodium, Sulphate, Sodium, Potassium, Calcium, Magnesium, etc)
How Much Biogas Can I Get From My Waste?
- Amount of biogas depends on the waste itself and design of the digester.
- Some digesters can yield 20 liters of biogas per kilogram of waste up to 800 liters per kilogram.
- Factors: waste quality, digester design, temperature, system operation, presence of oxygen.
• Average fuel value of methane = 1000 BTU/ft3
• Average fuel value of propane = 2500 BTU/ft3
• 1 BTU/ft3 = 37.2589 KJ/m3
• A British Thermal Unit (BTU) is the amount of heat energy needed to raise the temperature of one pound of water by one degree F
