134
6 Carrageenans
that transportation by road within the same country by distances of about 1500 km
(Gosh et al. 2015).
6.6.3 CO 2 Emission
The 118.6 kg of CO 2 equivalents is produced per kL of sap produced from K. alvarezii
(Ghosh et al. 2015). To put this in perspective, cultivation of maize on one hectare of
land results in production of 599 kg of CO 2 . The 142.5 L of sap which is equivalent
to a hectare produces 25.65 kg of CO 2 (Gosh et al. 2015). The process for producing
the sap results in the production of semi-refined carrageenan which can then be
further refined to produce refined carrageenan of higher grade. This process was
based on using the same cultivation process for carrageenan production, and the
process of extraction of sap is part of the process of carrageenan production. This
quantity of CO 2 includes the entire process of sap production from cultivation to the
factory gate. Following the process of separation of the sap from carrageenan, the
two processes then separate such that this estimated CO 2 emission is not the same as
that for carrageenan production as the process of refining to final packaging differs.
Therefore, the CO 2 emission for carrageenan production is expected to be greater
than 118.6 kg.
The environmental impact of the CO 2 emission from the process is weighed
against the benefits to the environment of carrageenan and its by-product. For example if sap is coproduced along with sap which is in turn sprayed on crops, this
substitutes the chemical fertilizers providing 21 g per l of potassium per sap. The
1000 L of sap substitutes 25.3 kg of chemical fertilizers (Ghosh et al. 2015).
6.6.4 Water Consumptions
Water serves the key role as the extraction solvent. It is also used in the washing of
the raw material and solvent for the salt for precipitation. Gosh et al. (2015) estimate
262.205 m
3 of water used in the production of 1 kl of unrefined carrageenan (sap). In
the reported experimental extractions (Manuhara et al. 2016), if we include the water
used in washing and soaking and as solvent and continuous media for the process, an
estimated 75 ml of water is used per gram of red algae processed. Although water is
recycled, the release of mineral acids and alkali and salts into the water cycle results
in gradual acidification and alterations of water salinity as the water is returned into
the sea. The cultivation of red algae could be integrated into the wastewater treatment
from the extraction process to achieve a net zero release of minerals into the water.
This will require modification of the process such that the acids, alkali, salts and
alcohols used can be broken down into minerals which are consumed by algae such
as nitrates and sulfates.
6 Carrageenans
that transportation by road within the same country by distances of about 1500 km
(Gosh et al. 2015).
6.6.3 CO 2 Emission
The 118.6 kg of CO 2 equivalents is produced per kL of sap produced from K. alvarezii
(Ghosh et al. 2015). To put this in perspective, cultivation of maize on one hectare of
land results in production of 599 kg of CO 2 . The 142.5 L of sap which is equivalent
to a hectare produces 25.65 kg of CO 2 (Gosh et al. 2015). The process for producing
the sap results in the production of semi-refined carrageenan which can then be
further refined to produce refined carrageenan of higher grade. This process was
based on using the same cultivation process for carrageenan production, and the
process of extraction of sap is part of the process of carrageenan production. This
quantity of CO 2 includes the entire process of sap production from cultivation to the
factory gate. Following the process of separation of the sap from carrageenan, the
two processes then separate such that this estimated CO 2 emission is not the same as
that for carrageenan production as the process of refining to final packaging differs.
Therefore, the CO 2 emission for carrageenan production is expected to be greater
than 118.6 kg.
The environmental impact of the CO 2 emission from the process is weighed
against the benefits to the environment of carrageenan and its by-product. For example if sap is coproduced along with sap which is in turn sprayed on crops, this
substitutes the chemical fertilizers providing 21 g per l of potassium per sap. The
1000 L of sap substitutes 25.3 kg of chemical fertilizers (Ghosh et al. 2015).
6.6.4 Water Consumptions
Water serves the key role as the extraction solvent. It is also used in the washing of
the raw material and solvent for the salt for precipitation. Gosh et al. (2015) estimate
262.205 m
3 of water used in the production of 1 kl of unrefined carrageenan (sap). In
the reported experimental extractions (Manuhara et al. 2016), if we include the water
used in washing and soaking and as solvent and continuous media for the process, an
estimated 75 ml of water is used per gram of red algae processed. Although water is
recycled, the release of mineral acids and alkali and salts into the water cycle results
in gradual acidification and alterations of water salinity as the water is returned into
the sea. The cultivation of red algae could be integrated into the wastewater treatment
from the extraction process to achieve a net zero release of minerals into the water.
This will require modification of the process such that the acids, alkali, salts and
alcohols used can be broken down into minerals which are consumed by algae such
as nitrates and sulfates.