Cultivation of Algae Polyculture in Municipal Wastewater with CO₂ Supply

In the past decades microalgae have been viewed as a promising source of sustainable biomass, because the cultivation of microalgae does not require arable land. Because the main use of the biomass has been envisaged as feedstock for biofuel, research has been directed on increasing the (lipid) yield of monospecies. However, because the production of biofuel from such virgin biomass is not economically viable, the production of the biomass should be coupled with other processes. In addition, cultivating polycultures may yield more biomass, while ensuring a stable culture. In this research Chlorella spp., Arthrospira platensis and Raphidocelis subcapitata were grown as a polyculture in municipal wastewater in order to remove nutrients. The results indicate that using microalgal polycultures may help reduce nitrogen and phosphorus by the level reglemented by the EU Council Directive. This may help reduce water treatment costs with simultaneous biomass production.