12.3.4.2 Microalgae Aquaculture
The algae production starts with the seeding of a microalgae starter-culture in the
closed photo-bioreactors on the algae floats. The key parameters for the algae
production are irradiance, nutrients and size of installation. As the microalgae are in
a closed system, the medium will be supplemented with some nutrients, such as
nitrogen (9 t/year), phosphorus and micronutrients (1.5 t/year) (Table 12.2). CO 2 is
also applied to enhance the production yield. This will be done by direct injection
from a 50 t cryogenic CO 2 storage with assistance of an air blower.
The online control system allows monitoring and controlling of the production
process inside the photo-bioreactors from board of the central unit. The unit is
operating valves and pumps and measures, among other parameters, temperature,
the pH value and the optical density in the system continuously. Environmental
ambient parameters like irradiance and temperature are also recorded.
When the microalgae culture reaches the desired concentration the culture is
harvested. The actual harvesting step of algae from the photo-bioreactors is carried
out on the satellite and the biomass is then shuttled to the central platform for
storage and further downstreaming. A two-step algae harvest is implemented with a
first step consisting in a pre-concentration of the algae suspension followed by a
second step of centrifugation. The dewatered algae biomass is then dried by
spray-dryer or solar-dryer and either cold stored until transport to the shore or
Table 12.2 Details on the algae aquaculture production unit, including dimension of floats, inputs
in terms of nutrients and output in terms of production as calculated based on a production analysis
Algae aquaculture
Component
Subsystem
Number
Units
Units
Number of units
30
Dimension
Length
200
m
Beam
50
m
Area
10,000
m²
Production per unit
65
t/a
Total production
(6–8 months, 30 units)
1950
t/a
Store nutrients
Nitrogen consumption per
unit
9.0
t/a
Phosphorus and
micronutrients
consumption per unit
1.5
t/a
Volume per unit
(Phytoplant)
400
m³
Production capacity
Max. production per week
750
t
Production per day
300
t
Source (TROPOS 2013c)
370
N. Papandroulakis et al.
The algae production starts with the seeding of a microalgae starter-culture in the
closed photo-bioreactors on the algae floats. The key parameters for the algae
production are irradiance, nutrients and size of installation. As the microalgae are in
a closed system, the medium will be supplemented with some nutrients, such as
nitrogen (9 t/year), phosphorus and micronutrients (1.5 t/year) (Table 12.2). CO 2 is
also applied to enhance the production yield. This will be done by direct injection
from a 50 t cryogenic CO 2 storage with assistance of an air blower.
The online control system allows monitoring and controlling of the production
process inside the photo-bioreactors from board of the central unit. The unit is
operating valves and pumps and measures, among other parameters, temperature,
the pH value and the optical density in the system continuously. Environmental
ambient parameters like irradiance and temperature are also recorded.
When the microalgae culture reaches the desired concentration the culture is
harvested. The actual harvesting step of algae from the photo-bioreactors is carried
out on the satellite and the biomass is then shuttled to the central platform for
storage and further downstreaming. A two-step algae harvest is implemented with a
first step consisting in a pre-concentration of the algae suspension followed by a
second step of centrifugation. The dewatered algae biomass is then dried by
spray-dryer or solar-dryer and either cold stored until transport to the shore or
Table 12.2 Details on the algae aquaculture production unit, including dimension of floats, inputs
in terms of nutrients and output in terms of production as calculated based on a production analysis
Algae aquaculture
Component
Subsystem
Number
Units
Units
Number of units
30
Dimension
Length
200
m
Beam
50
m
Area
10,000
m²
Production per unit
65
t/a
Total production
(6–8 months, 30 units)
1950
t/a
Store nutrients
Nitrogen consumption per
unit
9.0
t/a
Phosphorus and
micronutrients
consumption per unit
1.5
t/a
Volume per unit
(Phytoplant)
400
m³
Production capacity
Max. production per week
750
t
Production per day
300
t
Source (TROPOS 2013c)
370
N. Papandroulakis et al.