Tetraselmis suecica culture for CO2 bioremediation of untreated flue gas from a coal-fired power station

Abstract

The accumulation of atmospheric CO2, primarily due to combustion of fossil fuels, has been implicated in potential global climate change. The high rate of CO2 bioremediation by microalgae has emerged as a favourable method for reducing coal-fired power plant emissions. However, coal-fired power station flue gas contains other chemicals such as SOx which can inhibit microalgal growth. In the current study, the effect of untreated flue gas as a source of inorganic carbon on the growth of Tetraselmis in a 1000 L industrial-scale split-cylinder internal-loop airlift photobioreactor was examined. The culture medium was recycled after each harvest. Tetraselmis suecica grew very well in this airlift photobioreactor during the 7-month experiment using recycled medium from an electroflocculation harvesting unit. Increased medium SO4 2− concentration as high as 870 mg SO4 2− L−1 due to flue gas addition and media recycling had no negative effect on the overall growth and productivity of this alga. The potential organic biomass productivity and carbon sequestration using an industrial-scale airlift PBR at International Power Hazelwood, Gippsland, Victoria, Australia, are 178.9 ± 30 mg L−1 day−1 and 89.15 ± 20 mg ‘C’ L−1 day−1, respectively. This study clearly indicates the potential of growing Tetraselmis on untreated flue gas and using recycled medium for the purpose of biofuel and CO2 bioremediation.