is pumped back to the cultivation area [44]. Investment costs per
hectare are 22,000 10 €/ha for a pond, excluding mixing devices
[41]. Micro-algae concentration after settling is assumed to be
5 g/l [45]. A proven and widely applied separation technology is
a centrifuge, also chosen because of the ease of operation. Electricity
use varies between 3.3 and 4.5 MJ/m3 [19]. For this large-scale
application, we selected 3.5 MJ/m3. Equipment costs (excluding total
installation costs) of centrifuges are set at 8300 €/m3 [19]. The
percentage of dry solids after centrifugation increases to 15%
[19]. A newly developed harvesting technique using capillary,
cohesion and transpiration pull to harvest micro-algae is the AVS
harvest technology [51]. Although this method is still under development,
the claimed energy consumption and percentage dry solids
after harvesting are promising. As this technique shows
similarities to a continuous pressure filtration unit, the harvesting
costs are estimated based on the relative harvesting costs, as described
in [44]. In [44] the relative harvesting costs of a belt press
are 1.1 of a self-cleaning disc stack centrifuge. This factor is also
used to determine harvesting costs of the AVS harvesting technology:
energy consumption is 40 W/h for a capacity of 500 l/h. No
heat consumption is taken into account, due to the lack of data,