The Use of Biodigesters in the Treatment of Swine Manure …
109
When thinking about water, energy and food, first there is water. In the current
condition of the global population, estimated at more than 7 billion people by the
UN [66], which points out that more than half a billion people do not have access to
water (a number that is equivalent to the entire population of the Earth in the year of
the discovery of Brazil by Portuguese colonists, 1500), as well as 2 billion people
having access to water contaminated by fecal coliforms [34]. Marques et al. [51]
question how to feed the world population without compromising present and future
generations. Once the population and income changes of the coming decades tend
to cause an increase in global demand for food, such as meat (its production being
associated with environmental and public health impacts, as well as land and water
depletion).
For Liu et al. [48], the water footprint measures the human appropriation of
water resources for the consumptive use of surface and groundwater (blue) and soil
water (green), and to assimilate polluted water (gray). In this sense, it is important
to approach the amount of consumed water in livestock production and food in
relation to the adopted processes, as well as the technologies used. According to
this, Mekonnen and Hoekstra [54] present numbers that call the attention of those
who do not know this reality. They present consumption studies of the three types
of water: green, blue and gray; from the data presented in Table 1, we can analyze
the water footprint in the production processes. The expression “water footprint”
is a term that finds similarity and foundation in the previously created concept of
ecological footprint [58]. It is a concept that allows to evaluate with more precision
how countries establish their trade relations, thus bringing light to the analysis of
trade flows from the perspective of such an important input as water.
Table 1 shows the water footprint resulting from protein production. Among the
presented types (and observing the weighted average of water consumption per kilogram produced), it is found that pork production represents less than one-third of
water consumption to be produced when compared to beef. In addition, it is also
found that the quantities of water needed for pork production are equivalent to those
of cheese production. For Xiong et al. [70], decoding the way in which final demand
influences water consumption patterns is useful for understanding the discrepancy
between water supply and demand. Wang et al. [69] highlight that agriculture is the
basic unit that protects the world’s food security and is also the sector that uses the
largest amount of water in economic activities. Thus, combining the water, energy
and food nexus with the water footprint concept allows the establishment of costbenefit relations. So that, economic interests can be pursued, and natural resources
can be used in favor of the local economy, in a sustainable manner. Consequently
meeting the most well-known definition of sustainable development: seeking to meet
the needs of the current generation without compromising the ability of future generations to meet their own needs [61]. Once, the water footprint allows estimating the
water flows that are commercialized, whether in national or international trade [30].
The existing link between water, energy and food highlights the importance of
sanitation. It also encourages the reuse of water in possible processes, helping to
combat pollution of clean water and encouraging the use of polluted water as an
energy source. Polluted waters are rich in carbon, an energy source for the application
109
When thinking about water, energy and food, first there is water. In the current
condition of the global population, estimated at more than 7 billion people by the
UN [66], which points out that more than half a billion people do not have access to
water (a number that is equivalent to the entire population of the Earth in the year of
the discovery of Brazil by Portuguese colonists, 1500), as well as 2 billion people
having access to water contaminated by fecal coliforms [34]. Marques et al. [51]
question how to feed the world population without compromising present and future
generations. Once the population and income changes of the coming decades tend
to cause an increase in global demand for food, such as meat (its production being
associated with environmental and public health impacts, as well as land and water
depletion).
For Liu et al. [48], the water footprint measures the human appropriation of
water resources for the consumptive use of surface and groundwater (blue) and soil
water (green), and to assimilate polluted water (gray). In this sense, it is important
to approach the amount of consumed water in livestock production and food in
relation to the adopted processes, as well as the technologies used. According to
this, Mekonnen and Hoekstra [54] present numbers that call the attention of those
who do not know this reality. They present consumption studies of the three types
of water: green, blue and gray; from the data presented in Table 1, we can analyze
the water footprint in the production processes. The expression “water footprint”
is a term that finds similarity and foundation in the previously created concept of
ecological footprint [58]. It is a concept that allows to evaluate with more precision
how countries establish their trade relations, thus bringing light to the analysis of
trade flows from the perspective of such an important input as water.
Table 1 shows the water footprint resulting from protein production. Among the
presented types (and observing the weighted average of water consumption per kilogram produced), it is found that pork production represents less than one-third of
water consumption to be produced when compared to beef. In addition, it is also
found that the quantities of water needed for pork production are equivalent to those
of cheese production. For Xiong et al. [70], decoding the way in which final demand
influences water consumption patterns is useful for understanding the discrepancy
between water supply and demand. Wang et al. [69] highlight that agriculture is the
basic unit that protects the world’s food security and is also the sector that uses the
largest amount of water in economic activities. Thus, combining the water, energy
and food nexus with the water footprint concept allows the establishment of costbenefit relations. So that, economic interests can be pursued, and natural resources
can be used in favor of the local economy, in a sustainable manner. Consequently
meeting the most well-known definition of sustainable development: seeking to meet
the needs of the current generation without compromising the ability of future generations to meet their own needs [61]. Once, the water footprint allows estimating the
water flows that are commercialized, whether in national or international trade [30].
The existing link between water, energy and food highlights the importance of
sanitation. It also encourages the reuse of water in possible processes, helping to
combat pollution of clean water and encouraging the use of polluted water as an
energy source. Polluted waters are rich in carbon, an energy source for the application