such as Bacillus spp., Lactobacillus spp. and Corynebacterium spp., yeast-like Candida, Saccharomyces and Protozoa (Nene 1999; Randhawa and Kullar 2011). However,
different bacterial genes that include Escherichia coli,
Enterobacter aerogenes, Klebsiella pneumoniae, Klebsiellaoxytoca, Kluyvera spp., Citrobacter koseri, Morgarella
morganii, Providencia stuartii, Pasteurella spp., Pseudomonas spp., Providencia alcaligenes are also present in
cow dung (Sawant et al. 2007).
3.2 Physical Properties
Physical properties such as fixed carbon, volatiles, heating
value, ash and moisture are prerequisites for assessing the
feasibility of using cow dung as a sustainable source of
biomass. Good understanding of the physical properties
helps improve the methods of conversion and handling the
process of storage. This reduces the treatment cost and
makes the process of cow dung waste treatment more efficient, sustainable and environment friendly.
Figure 4 shows the physical properties of cow dung,
which includes percentage content of fixed carbon, volatiles,
ash and moisture. Additionally, it also represents the heating
value, which is significant for energy analysis. About
83.91% of volatiles are present in cow manure that makes
them the perfect feed material for the gasification process.
The moisture content of cow dung generally remains 39.24
wt% and varies slightly in different sources (Font-Palma
2019). The higher value of moisture content has an essential
consequence in the conversion of the thermochemical process as in order to dry the manure, with low moisture content
the cow dung can be dried quickly. The ash content generally varies from 10.8 to 45.2 wt% on a dry basis; 27.72% is a
constant quoted in some sources (Font-Palma 2019). The ash
content of cow dung (4.7–10.3 wt% dry basis) is higher than
in wheat straw (Carlin et al. 2011). Hence, the high-ash
content in cattle manure can create certain problems
including agglomeration, sintering, erosion, corrosion and
deposition. These phenomena occur due to the low melting
point of the ash. However, the composition and content of
ash usually depend on the bedding type used in different
countries. According to Carlin et al., the difference between
the properties of low and high-ash mass depends on the
management practices of manure (Carlin et al. 2009). Generally, the manure with low-ash contents is collected from
cement-paved lots. Manure with higher ash content is collected from unpaved yards. The last two properties of the
figure are heating values and fixed carbons with a value of
maximum 20.08 MJ/kg and 16.09 wt%, respectively.
However, the heating value of cow dung is slightly lower
than the heating value of coal (16–24 MJ/kg for
sub-bituminous) (Font-Palma 2019).
Figure 5 shows the elements of cow dung in the dry and
ash-free sample. The highest percentage is carbon, 49% of
the total (Carlin et al. 2009). The high amount of carbon
gives the cow dung more heating value and makes it efficient
to use as fuel. The second-highest is oxygen which is almost
41%, which ensures efficient combustion. Apart from carbon
and oxygen, there is a number of other elements as well,
including hydrogen, which is almost 7%. There is a minimal
amount of nitrogen and sulphur, 2% and 1%, respectively.
Generally, a high amount of sulphur content in organic form
is harmful because it emits SOx during thermochemical
conversion. Emission of SOx in the air can be a cause of acid
rain (Carlin et al. 2009). Even though the Sulphur content in
cow dung is only 1.36%, it is higher compared to other
organic products. The elemental analysis shows that cow
dung has much economic value to use as fuel (because of
carbon and oxygen) and as fertiliser (because of Hydrogen
and Nitrogen). However, the harmful effect of SOx emissions cannot be neglected.
3.3 Chemical Properties
As mentioned earlier, cow dung is a mixture of organic
materials as well as macro and micronutrients. There is also
a certain pH, ash and other minor components. In Fig. 6, the
minerals and nutrients are arranged in the periodic table as
their original position, and the metals are red, transition
metals are green, and non-metals are shown in blue. The
other properties, including pH, ash content, organic carbon,
organic nitrogen and C/N ratio, are represented in Fig. 6.
Soil should be treated with manures having rich nutrients
as they are pre-requisite of good fertiliser. The mineral
composition includes 14 different macro and micronutrients.
The average quantity of macronutrients in the plant, such as
carbon, nitrogen, phosphorus, potassium, sulphur, calcium
and magnesium are higher than the micronutrients (Iron,
zinc, copper, manganese, boron and sodium). As stated
earlier in physical properties, carbon is higher than all
nutrients, which is about 75 mg/g. Surprisingly calcium is
the second-highest amount of nutrient, 19 mg/g, and it even
exceeds the concentration of nitrogen (Kirchmann and
Witter 1992). Phosphorus has the third place among all
minerals having a concentration of about 9 mg/g followed
by potassium having 7.3 mg/g. Magnesium and nitrogen
almost have the same concentration of 6 mg/g and 6.1 mg/g,
respectively. The concentration of sulphur is about 3.6 mg/g,
which risks the formation of SOx, and aluminium is about
1.4 mg/g. Among the micronutrients, iron (Fe) has the
highest amount of concentration, which is about 2.03 mg/g.
manganese and zinc have a concentration of 154 µg/g and
127 µg/g, respectively. Boron and sodium have minimal
presence 15 µg/g, and 10 µg/g, respectively.
220
A. A. Ananno et al.
different bacterial genes that include Escherichia coli,
Enterobacter aerogenes, Klebsiella pneumoniae, Klebsiellaoxytoca, Kluyvera spp., Citrobacter koseri, Morgarella
morganii, Providencia stuartii, Pasteurella spp., Pseudomonas spp., Providencia alcaligenes are also present in
cow dung (Sawant et al. 2007).
3.2 Physical Properties
Physical properties such as fixed carbon, volatiles, heating
value, ash and moisture are prerequisites for assessing the
feasibility of using cow dung as a sustainable source of
biomass. Good understanding of the physical properties
helps improve the methods of conversion and handling the
process of storage. This reduces the treatment cost and
makes the process of cow dung waste treatment more efficient, sustainable and environment friendly.
Figure 4 shows the physical properties of cow dung,
which includes percentage content of fixed carbon, volatiles,
ash and moisture. Additionally, it also represents the heating
value, which is significant for energy analysis. About
83.91% of volatiles are present in cow manure that makes
them the perfect feed material for the gasification process.
The moisture content of cow dung generally remains 39.24
wt% and varies slightly in different sources (Font-Palma
2019). The higher value of moisture content has an essential
consequence in the conversion of the thermochemical process as in order to dry the manure, with low moisture content
the cow dung can be dried quickly. The ash content generally varies from 10.8 to 45.2 wt% on a dry basis; 27.72% is a
constant quoted in some sources (Font-Palma 2019). The ash
content of cow dung (4.7–10.3 wt% dry basis) is higher than
in wheat straw (Carlin et al. 2011). Hence, the high-ash
content in cattle manure can create certain problems
including agglomeration, sintering, erosion, corrosion and
deposition. These phenomena occur due to the low melting
point of the ash. However, the composition and content of
ash usually depend on the bedding type used in different
countries. According to Carlin et al., the difference between
the properties of low and high-ash mass depends on the
management practices of manure (Carlin et al. 2009). Generally, the manure with low-ash contents is collected from
cement-paved lots. Manure with higher ash content is collected from unpaved yards. The last two properties of the
figure are heating values and fixed carbons with a value of
maximum 20.08 MJ/kg and 16.09 wt%, respectively.
However, the heating value of cow dung is slightly lower
than the heating value of coal (16–24 MJ/kg for
sub-bituminous) (Font-Palma 2019).
Figure 5 shows the elements of cow dung in the dry and
ash-free sample. The highest percentage is carbon, 49% of
the total (Carlin et al. 2009). The high amount of carbon
gives the cow dung more heating value and makes it efficient
to use as fuel. The second-highest is oxygen which is almost
41%, which ensures efficient combustion. Apart from carbon
and oxygen, there is a number of other elements as well,
including hydrogen, which is almost 7%. There is a minimal
amount of nitrogen and sulphur, 2% and 1%, respectively.
Generally, a high amount of sulphur content in organic form
is harmful because it emits SOx during thermochemical
conversion. Emission of SOx in the air can be a cause of acid
rain (Carlin et al. 2009). Even though the Sulphur content in
cow dung is only 1.36%, it is higher compared to other
organic products. The elemental analysis shows that cow
dung has much economic value to use as fuel (because of
carbon and oxygen) and as fertiliser (because of Hydrogen
and Nitrogen). However, the harmful effect of SOx emissions cannot be neglected.
3.3 Chemical Properties
As mentioned earlier, cow dung is a mixture of organic
materials as well as macro and micronutrients. There is also
a certain pH, ash and other minor components. In Fig. 6, the
minerals and nutrients are arranged in the periodic table as
their original position, and the metals are red, transition
metals are green, and non-metals are shown in blue. The
other properties, including pH, ash content, organic carbon,
organic nitrogen and C/N ratio, are represented in Fig. 6.
Soil should be treated with manures having rich nutrients
as they are pre-requisite of good fertiliser. The mineral
composition includes 14 different macro and micronutrients.
The average quantity of macronutrients in the plant, such as
carbon, nitrogen, phosphorus, potassium, sulphur, calcium
and magnesium are higher than the micronutrients (Iron,
zinc, copper, manganese, boron and sodium). As stated
earlier in physical properties, carbon is higher than all
nutrients, which is about 75 mg/g. Surprisingly calcium is
the second-highest amount of nutrient, 19 mg/g, and it even
exceeds the concentration of nitrogen (Kirchmann and
Witter 1992). Phosphorus has the third place among all
minerals having a concentration of about 9 mg/g followed
by potassium having 7.3 mg/g. Magnesium and nitrogen
almost have the same concentration of 6 mg/g and 6.1 mg/g,
respectively. The concentration of sulphur is about 3.6 mg/g,
which risks the formation of SOx, and aluminium is about
1.4 mg/g. Among the micronutrients, iron (Fe) has the
highest amount of concentration, which is about 2.03 mg/g.
manganese and zinc have a concentration of 154 µg/g and
127 µg/g, respectively. Boron and sodium have minimal
presence 15 µg/g, and 10 µg/g, respectively.
220
A. A. Ananno et al.