“What we are doing to the
forests of the world is but a
mirror reflection of what we
are doing to ourselves and to
“A nation that destroys its soils
destroys itself. Forests are the
lungs of our land, purifying the
air and giving fresh strength to
our people. ”
Franklin D. Roosevelt
What is Bio Gas
• Biogas is an alternative and renewable energy that can
be produced by the anaerobic (absence of oxygen)
decomposition of organic matter.
• Biogas can be produced from regionally available raw
materials such as recycled waste and is a renewable
• Typically, using organic wastes as the major input, the
systems produce biogas that contains 55% to 70%
CH4 and 30% to 45% CO2.
What is Bio Gas
• Biogas is produced by anaerobic digestion with
anaerobic bacteria orfermentation of biodegradable
materials such as manure, sewage, municipal
waste, green waste, plant material, and crops.
• The gases methane, hydrogen, and carbon
monoxide (CO) can be combusted or oxidized with
• Landfill gas is produced by wet organic waste
decomposing under anaerobic conditions in a
What is Bio Gas
• This energy release allows biogas to be used as a
fuel; it can be used for any heating purpose, such as
• It can also be used in a gas engine to convert the
energy in the gas into electricity and heat.
• Biogas can be compressed, the same way natural
gas is compressed to CNG, and used to power motor
In the UK, for example,
biogas is estimated to have
the potential to
17% of vehicle fuel.
• Raw biogas produced from digestion is roughly
60% methane and 29% CO2 with trace elements
of H2S So it is not high quality enough to be used as
fuel gas for machinery.
• The corrosive nature of H2S alone is enough to
destroy the internals of a plant.
• Methane in biogas can be concentrated via a biogas
upgrader to the same standards as fossil natural
gas, which itself has had to go through a cleaning
process, and becomes biomethane
• There are four main methods of upgrading: water
washing, pressure swing absorption, selexol absorption,
and amine gas treating
• The most prevalent method is water washing where
high pressure gas flows into a column where the carbon
dioxide and other trace elements are scrubbed by
cascading water running counter-flow to the gas
Reduced GHG emissions
Potential reduction of VOC emissions
Pathogen and weed seed control
Improved water quality
Biogas In Pakistan
National Bio Gas Program
offer fix dom (6 m3 to 18 m3 )
small and medium bio gas
plants is generally used for
cooking and lighting purposes.
Large units (25 m3 ,35 m3 , 50
m3, 100m3,200m3 )or more
mega units produce this gas in
large quantities and can be used,
peter engines (tube wells , and
What is Biogas Digestion?
• Biogas Digestion is the process of taking biogas
to produce electricity, heat, or hot water
• Biogas means a gas formed by carbon dioxide
and methane from breakdown of organic
materials such as manure.
What is a Digester?
• Digester is a vessel or container where the
biogas process takes place. Bacteria breaks
down manure or other waste products to
• Products may be fed into the chamber such as
manure or the container could be used to
cover a place that is already giving off biogas
such as a swamp or a landfill.
Manure collection and handling.
By-Product recovery and effluent use
Elements of Anaerobic Digestion Systems
Biogas Handling and Use
How Digester Works
• Temperature must be kept between 65
degrees and 150 degrees
• 4 Types of bacteria breakdown the waste
– Hydrolytic breaks organic material to
simple sugar and amino acids
– Fermentative then converts to organic
– Acidogenic convert to carbon dioxide,
acetate, and hydrogen
– Methanogenic produces biogas
This is the first step where particulate materials get
converted to soluble compounds suitable for
further breakdown in the next step.
The second step of degradation is known as
fermentation or acidogenesis where the
products of hydrolysis such as simple sugars,
amino acids, fatty acids etc. break down further
and produce final products of fermentation such
as H2, CO2 and acetate.
Combined Heat and Power
• Also known as cogeneration
• Using the heated water for other purposes
such as heating buildings or creating
Biogas Digester System
• Releases Nitrogen and ammonia into the
atmosphere both of which hazardous
• Can release Hydrogen Sulfide a very toxic gas
• Methane released can create explosive
• Should raw materials get into water supply
can contaminate the water
• Transportation is of a concern because
methane is explosive although new technology
may allow it to be stored in powder form