LCA studies performed on microalgae

LCA studies performed on microalgae cultivation systems
(Clarens et al., 2010; Yang et al., 2011), concluded that economics
of microalgae-based biodiesel will be improved significantly by
reducing water and nutrients demand. This can be met by continuous
reuse of culture medium and using impaired water sources
such as wastewater. However, 100% water recycling is impossible
even under perfect operation. Significant amount of water is lost
due to water evaporation and during harvesting and drying of microalgae
biomass (Guieysse et al., 2013). Since majority of the water
footprint comes from the cultivation system, it is necessary to
recover and recycle the maximum amount of used medium for further
cultivation. In addition, a large quantity of unused nutrients
loss is expected if water after the harvesting process is not recirculated
into the cultivation system. This will also contribute to the
gray water footprint. Water recycling after biomass harvesting is
expected to reduce the water requirement and nutrients demand,
which is essential for long-term sustainability of microalgal
biofuels.