82
4 Alginates
energy-consuming process in the future. This is the stage in the extraction where
the most heat is consumed. Further energy is consumed in running the equipment
for dewatering processes which could be done by filtration or gel pressing. These
consume less energy than evaporation of the sodium alginate from aqueous solution.
Assessment of algae seaweed production in Ireland revealed that 75.1% of seaweed sourcing resource consumption is attributed to fossil fuel consumption required
for transportation and machinery to operate aquaculture (where the algae are not from
wild stock) (Taelman et al. 2015).
4.6.5 Water Consumption and Wastewater Generation
An estimated 1500 MT of water used in the extraction process and further 3900 MT
of water for dilution in production of 26 MT of sodium alginate dry pellets (10%
moisture content) in the case study presented by Konda et al. (2015). Harvesting
brown algae from wild stocks makes little direct use of water, and alginate production
makes use of a lot of water to the extent that the survival of an alginate production
factory is largely affected by reliable availability of abundant water. The wastewater
generated has high pH from the initial extraction stage while the later extraction stage
will generate wastewater containing calcium or acid, depending on the method used.
It also contains the compounds used to decolorize. The generated wastewater can
either be recycled in-house or sent to wastewater treatment plant before releasing it
to the sea in accordance with the local laws.
4.6.6 Carbon Dioxide Emission
Commercial alginate extraction process results in CO 2 emission from the running
of the alginate production facilities. On the other hand, seaweeds are photosynthetic
aquatic plants, whose rate of photosynthesis is 3–4 times more efficient than that
of terrestrial plants. The CO 2 emission in the extraction process is therefore partly
compensated for by the CO 2 removal during photosynthesis. This is even more
advantageous for aquatic plants as the plants do not remove nutrients from the soil.
4.6.7 Solid Waste Generated
The main solid waste generated is the seaweed residue after the alkali sodium alginate
extraction. The solid residue also contains the formalin and filtration aid if used.
Although details of the process used by commercial producers in the treatment and
deposition of the solid waste generated from alginate production from seaweed are
not provided here, some research publications have presented innovative ways of
4 Alginates
energy-consuming process in the future. This is the stage in the extraction where
the most heat is consumed. Further energy is consumed in running the equipment
for dewatering processes which could be done by filtration or gel pressing. These
consume less energy than evaporation of the sodium alginate from aqueous solution.
Assessment of algae seaweed production in Ireland revealed that 75.1% of seaweed sourcing resource consumption is attributed to fossil fuel consumption required
for transportation and machinery to operate aquaculture (where the algae are not from
wild stock) (Taelman et al. 2015).
4.6.5 Water Consumption and Wastewater Generation
An estimated 1500 MT of water used in the extraction process and further 3900 MT
of water for dilution in production of 26 MT of sodium alginate dry pellets (10%
moisture content) in the case study presented by Konda et al. (2015). Harvesting
brown algae from wild stocks makes little direct use of water, and alginate production
makes use of a lot of water to the extent that the survival of an alginate production
factory is largely affected by reliable availability of abundant water. The wastewater
generated has high pH from the initial extraction stage while the later extraction stage
will generate wastewater containing calcium or acid, depending on the method used.
It also contains the compounds used to decolorize. The generated wastewater can
either be recycled in-house or sent to wastewater treatment plant before releasing it
to the sea in accordance with the local laws.
4.6.6 Carbon Dioxide Emission
Commercial alginate extraction process results in CO 2 emission from the running
of the alginate production facilities. On the other hand, seaweeds are photosynthetic
aquatic plants, whose rate of photosynthesis is 3–4 times more efficient than that
of terrestrial plants. The CO 2 emission in the extraction process is therefore partly
compensated for by the CO 2 removal during photosynthesis. This is even more
advantageous for aquatic plants as the plants do not remove nutrients from the soil.
4.6.7 Solid Waste Generated
The main solid waste generated is the seaweed residue after the alkali sodium alginate
extraction. The solid residue also contains the formalin and filtration aid if used.
Although details of the process used by commercial producers in the treatment and
deposition of the solid waste generated from alginate production from seaweed are
not provided here, some research publications have presented innovative ways of