PROGRAMME

Cultivation of microalgae with the addition of wastewater and carbon dioxide (CO2) could be a cost-effective treatment method which at the same time provides essential nutrients for biomass production and reduces CO2 emissions. The potential use of cheese whey for Arthrospira (spirulina) platensis cultivation could provide a sustainable solution aligned with circular economy principles for the treatment of dairy industry wastewater, in regions such as North Aegean (Greece). The main objectives of this research are to investigate the parameters affecting the growth of Arthrospira platensis biomass in whey-rich solutions with the addition of CO2 using an airlift vertical plate photobioreactor. During the first two experimental sets (14 days each), the effect of different whey dilution ratios and irradiation conditions on biomass productivity were studied and the results show that the 10% (v/v) whey cheese concentration performed best in both experimental lighting sets, continuous light/dark cycles. The highest biomass production (1.06 g l −1) was achieved in 14-day experiments at pH 10.5 and with a 12-h dark/light photoperiod. In the light/dark cycle culture, about 85% COD removal and 70% NO−3 − N consumption was measured. Regarding the third experimental set using CO2, the results show that the addition of 1mL CO2/min lead to better performance in terms of optical density. It seems that CO2 accelerates the production of Arthrospira platensis in a short period of time and provides long-term environmental benefit.