vegetative cover, proficient transformation methods, renewable resources being both
used as a material and as a source of energy, and the residual materials to be used as
fertilizer). The sustainability principle also applies to the biogas sector, and it can’t
be offered as lasting energy source if those conditions are not fulfilled.
The anaerobic digestion process also reduces environmentally harmful methane
emanations to quite an extent and could also reduce the nitrous oxide emissions,
having an impact on the climate (Möller 2015). To a certain degree, bad smell-causing
substances are also decomposed and neutralized. Other environmental advantages
include the utilization and reduction of waste during electricity or heat generation,
and the remaining digestate can also be used as a fertilizer. Most of non-crude-oilproducing countries are dependent on energy imports; thus with the directed development of such renewable energy systems, they could reach the goal of energy independence and stable supply. According to the Renewable Energy Sources Act (EEG),
production of electricity and heat (combined heat and power production – CHP)
primarily uses biogas for feeding biogas-sourced electricity into the power grids.
Generally, CHP units consist of a biogas-powered combustion engine, driving a
generator to produce electrical energy. To use biogas as a substitute for natural gas,
it first needs to be purified of unwanted constituent elements (such that the CO 2 needs
to be separated) leading to higher methane content. The upgraded biogas, called
biomethane (or bio-natural gas), could then be stored in the extensive gas grid or
transported to be used at any site. It can also be used in other domestic purpose like gas
stove fuel and lighting (Pfeifer and Obernberger 2007; Rutz et al. 2015).
3.2
Source of Organic Waste for Biogas Production
Biogas is produced by anaerobic digestion, a natural biological process which
stabilizes organic waste in the absence of oxygen. The important parameter to be
considered in anaerobic digestion is the source and type of feedstock used. Almost
any organic material can be utilized such as newspapers, restaurant and kitchen food
waste, animal waste, agricultural waste, and waste from different types of food and
beverage industries, leather processing industries, etc. Organic waste is generated
from daily human activities and from the industries; thereby the amount of organic
waste produced is amassed each year as the population increase. Developing
countries deal with the organic waste in different ways, like soil improvement, for
animal raising and also to provide a source of energy.
3.3
Materials to Be Excluded from Anaerobic Digesters
Toxic, inorganic, and poorly degradable material should be excluded from the
feedstock. Toxic compounds like ammonium and sulphur, if present in feedstock
at high concentration, could inhibit anaerobic organisms. Poorly degradable material
requires more time for breakdown and to convert into biogas. Inorganic material like
68
S. Elangovan et al.
used as a material and as a source of energy, and the residual materials to be used as
fertilizer). The sustainability principle also applies to the biogas sector, and it can’t
be offered as lasting energy source if those conditions are not fulfilled.
The anaerobic digestion process also reduces environmentally harmful methane
emanations to quite an extent and could also reduce the nitrous oxide emissions,
having an impact on the climate (Möller 2015). To a certain degree, bad smell-causing
substances are also decomposed and neutralized. Other environmental advantages
include the utilization and reduction of waste during electricity or heat generation,
and the remaining digestate can also be used as a fertilizer. Most of non-crude-oilproducing countries are dependent on energy imports; thus with the directed development of such renewable energy systems, they could reach the goal of energy independence and stable supply. According to the Renewable Energy Sources Act (EEG),
production of electricity and heat (combined heat and power production – CHP)
primarily uses biogas for feeding biogas-sourced electricity into the power grids.
Generally, CHP units consist of a biogas-powered combustion engine, driving a
generator to produce electrical energy. To use biogas as a substitute for natural gas,
it first needs to be purified of unwanted constituent elements (such that the CO 2 needs
to be separated) leading to higher methane content. The upgraded biogas, called
biomethane (or bio-natural gas), could then be stored in the extensive gas grid or
transported to be used at any site. It can also be used in other domestic purpose like gas
stove fuel and lighting (Pfeifer and Obernberger 2007; Rutz et al. 2015).
3.2
Source of Organic Waste for Biogas Production
Biogas is produced by anaerobic digestion, a natural biological process which
stabilizes organic waste in the absence of oxygen. The important parameter to be
considered in anaerobic digestion is the source and type of feedstock used. Almost
any organic material can be utilized such as newspapers, restaurant and kitchen food
waste, animal waste, agricultural waste, and waste from different types of food and
beverage industries, leather processing industries, etc. Organic waste is generated
from daily human activities and from the industries; thereby the amount of organic
waste produced is amassed each year as the population increase. Developing
countries deal with the organic waste in different ways, like soil improvement, for
animal raising and also to provide a source of energy.
3.3
Materials to Be Excluded from Anaerobic Digesters
Toxic, inorganic, and poorly degradable material should be excluded from the
feedstock. Toxic compounds like ammonium and sulphur, if present in feedstock
at high concentration, could inhibit anaerobic organisms. Poorly degradable material
requires more time for breakdown and to convert into biogas. Inorganic material like
68
S. Elangovan et al.