15 Sustainability Metrics in the Microalgae-Based …
383
more compact and optimized equipments, which reflects in a processing plant with
less occupation of land use and with lower spending on electricity.
Terrestrial acidification is an indicator related to emissions of air pollutants that
result in acid rain (Reuss and Johnson 2012). Thus, for microalgae-based β-carotene
and astaxanthin, the values found were in the order 4.52 and 14.92 kg SO 2eq , respectively. On the other hand, to obtain β-carotene and astaxanthin synthetics the values
found were in the order of 0.084 kg SO 2eq and 0.071 kg SO 2eq , respectively. The
highest results for the production of the microalgae-based pigment have related to
the greater fossil energy resources for the operation of the production plant. Fossil
fuels consumption is found to be the largest contributing parameter for gaseous pollutants emissions in industrial processes; once only 20–30% of the chemical energy of
the fuel burned is typically transformed into useful work or heating, the rest being
dissipated into the atmosphere as polluting gases (Bilgen et al. 2014). In this sense,
in order to reduce the acidification potential of microalgae-based processes, it is
necessary to increase the energy efficiency of these technological routes.
The eutrophication potential represents the contribution of the nutrients as phosphates and nitrates to ecosystems in river and lakes. In the present study, were found
values in order to 1.62 and 5.34 kg N eq for microalgae-based β-carotene and astaxanthin, respectively. However, for β-carotene and astaxanthin synthetics, the emissions
of eutrophication potential were next to zero, with values of 0.030 and 0.025 kg N eq ,
respectively. These values are related to the low fossil energy consumption summed
to the high yields of chemical reagents in pigments of the processing plant of synthetic
pigments.
The water footprint is a metric that counts the direct and indirect use of water as
well as pollution. Given this aspect, the water footprints were quantified and 27.77 m
3
for the production of microalgae-based β-carotene was required. While for production of microalgae-based astaxanthin, 83.0 m
3 was required. In contrast, in synthetic
production, the values for β-carotene and astaxanthin were 0.03 m
3 and 0.01 m
3 ,
respectively. Water use represents a challenge of particular significance for commercial microalgae cultivation. According to Guieysse et al. (2013), more than 1 metric
ton of process water must be handled for each kg of microalgae biomass produced;
being able to suffer from variability arising from process operation. This variability is evident in the comparison among the microalgae-based pigment production
scenarios; the microalgae-based astaxanthin showed higher values when compared
to the microalgae-based β-carotene. The results are related to the water used for twosystem operation on the cultivation of Haematococcus pluvialis. Some companies
adopt strategies for the improvement of the microalgae-based pigments production
processes such as using ocean water as a water source (Lorenz and Cysewski 2000).
According to Yang et al. (2011) using seawater or wastewater can reduce the life
cycle freshwater usage by as much as 90%.
The ozone depletion potential (ODP) is an impact category related to emissions of
air pollutants that result in degradation to the ozone layer. Thus, the production of the
microalgae-based β-carotene and astaxanthin showed average values of 0.00025 and
0.00085 kg CFC-11 eq, respectively. Comparatively, were determined for synthetic
production of β-carotene and astaxanthin, values in the order of 0.0000048 and
383
more compact and optimized equipments, which reflects in a processing plant with
less occupation of land use and with lower spending on electricity.
Terrestrial acidification is an indicator related to emissions of air pollutants that
result in acid rain (Reuss and Johnson 2012). Thus, for microalgae-based β-carotene
and astaxanthin, the values found were in the order 4.52 and 14.92 kg SO 2eq , respectively. On the other hand, to obtain β-carotene and astaxanthin synthetics the values
found were in the order of 0.084 kg SO 2eq and 0.071 kg SO 2eq , respectively. The
highest results for the production of the microalgae-based pigment have related to
the greater fossil energy resources for the operation of the production plant. Fossil
fuels consumption is found to be the largest contributing parameter for gaseous pollutants emissions in industrial processes; once only 20–30% of the chemical energy of
the fuel burned is typically transformed into useful work or heating, the rest being
dissipated into the atmosphere as polluting gases (Bilgen et al. 2014). In this sense,
in order to reduce the acidification potential of microalgae-based processes, it is
necessary to increase the energy efficiency of these technological routes.
The eutrophication potential represents the contribution of the nutrients as phosphates and nitrates to ecosystems in river and lakes. In the present study, were found
values in order to 1.62 and 5.34 kg N eq for microalgae-based β-carotene and astaxanthin, respectively. However, for β-carotene and astaxanthin synthetics, the emissions
of eutrophication potential were next to zero, with values of 0.030 and 0.025 kg N eq ,
respectively. These values are related to the low fossil energy consumption summed
to the high yields of chemical reagents in pigments of the processing plant of synthetic
pigments.
The water footprint is a metric that counts the direct and indirect use of water as
well as pollution. Given this aspect, the water footprints were quantified and 27.77 m
3
for the production of microalgae-based β-carotene was required. While for production of microalgae-based astaxanthin, 83.0 m
3 was required. In contrast, in synthetic
production, the values for β-carotene and astaxanthin were 0.03 m
3 and 0.01 m
3 ,
respectively. Water use represents a challenge of particular significance for commercial microalgae cultivation. According to Guieysse et al. (2013), more than 1 metric
ton of process water must be handled for each kg of microalgae biomass produced;
being able to suffer from variability arising from process operation. This variability is evident in the comparison among the microalgae-based pigment production
scenarios; the microalgae-based astaxanthin showed higher values when compared
to the microalgae-based β-carotene. The results are related to the water used for twosystem operation on the cultivation of Haematococcus pluvialis. Some companies
adopt strategies for the improvement of the microalgae-based pigments production
processes such as using ocean water as a water source (Lorenz and Cysewski 2000).
According to Yang et al. (2011) using seawater or wastewater can reduce the life
cycle freshwater usage by as much as 90%.
The ozone depletion potential (ODP) is an impact category related to emissions of
air pollutants that result in degradation to the ozone layer. Thus, the production of the
microalgae-based β-carotene and astaxanthin showed average values of 0.00025 and
0.00085 kg CFC-11 eq, respectively. Comparatively, were determined for synthetic
production of β-carotene and astaxanthin, values in the order of 0.0000048 and