What is anaerobic digestion?
Anaerobic digestion (AD) is a series of natural processes in which microorganisms break down biodegradable material in the absence of
oxygen, used for industrial or domestic purposes to manage waste and/or to produce renewable energy.
What are the benefits of anaerobic digestion?
The use of anaerobic digestion to treat organic waste in combination with power generation provides a variety of benefits. These may be
classified into three groups; environmental, energy and economic benefits. A list of these benefits is described below:
Elimination of malodorous compounds
Reduction of pathogens
Deactivation of weed seeds
Production of sanitized compost
Decrease in GHG emission
Reduced dependence on inorganic fertilizers by capture and reuse of nutrients
Promotion of carbon sequestration
Beneficial reuse of recycled water
Protection of groundwater and surface water resources
Improved social acceptance
Anaerobic digestion is a net energy-producing process
A biogas facility generates high-quality renewable fuel
Surplus energy as electricity and heat is produced during anaerobic digestion of biomass
Anaerobic digestion reduces reliance on fossil fuels
Such a facility contributes to decentralized, distributed power systems
Biogas is a rich source of electricity, heat, and transportation fuel
Anaerobic digestion transforms waste liabilities into new profit centers
The time devoted to moving, handling and processing waste is minimized
Anaerobic digestion adds value to negative value waste stream
Income can be obtained from the sale of power, carbon credits, the processing of waste (tipping fees), and sale of organic fertilizer
Power tax credits may be obtained from each kWh of power produced
It reduces dependence on fossil fuel
What is biogas?
Biogas is a byproduct of the decomposition of organic matter by anaerobic bacteria.
Biogas is typically composed of 60% methane and 40% CO2. It is similar to natural gas which is composed of 99% methane.
Biogas is a clean and renewable energy that may be substituted to natural gas to cook, to produce vapor, hot water or to generate electricity.
What type of waste produces biogas?
Any organic waste has the ability to produce biogas: human excreta, manure, animal slurry, fruit and vegetable waste, slaughterhouse waste,
palm oil mill effluent (POME), meat packing waste, dairy factory waste, brewery and distillery waste, etc.
Fiber rich wastes like wood, leaves, etc. make poor feedstock for digesters as they are difficult to digest.
How much biogas can I get out of my waste?
The amount of biogas you can extract from your organic waste depends on waste quality and handling practices, digester design, and proper
operation of the anaerobic digestion system.
Where is biogas produced?
Biogas is normally produced in nature by the anaerobic degradation of organic waste in soil, marshes, ocean, etc.
Biogas is also produced in landfills where organic food waste degrades in anaerobic conditions.
Biogas can be produced in anaerobic digesters.
Since methane is a potent greenhouse gas, isn’t it irresponsible to produce biogas?
Methane has a greenhouse gas (GHG) heating factor 21 times higher than CO2.
Combustion of biogas converts methane into CO2 and reduces the GHG impact by over 20 times.
By extracting methane out of waste and using it to produce heat and/or electricity we ensure that the waste will not degrade in an open
environment therefore reducing direct methane atmospheric emissions. Moreover, the energy provided by the biogas is likely to displace
fossil fuel which is the main contributor to GHG emissions.
Biogas energy is considered carbon neutral, since carbon emitted by its combustion comes from carbon fixed by plants (natural carbon cycle).