Influence of Flue Gas Components on the Growth Rate of Chlorella vulgaris and Scenedesmus acutus

Atmospheric carbon dioxide levels have increased since the industrial revolution due to the increase in combustion of fossil fuels. One possible alternative strategy is the use of microalgae for CO 2 capture and recycling. Major components in coal-derived flue gas that may accumulate and effect algae growth include both sulfur oxides and fly ash. However, in practical application, sulfur oxides will be converted quickly to the acid product (H 2 SO 4 ) in the aerobic aqueous conditions of algae cultivation. In this article, the influence of elevated H 2 SO 4 levels and the presence of coal-derived fly ash were investigated. As the H 2 SO 4 level increased, algae growth was inhibited and finally ceased; however, this affect could be minimized by the addition of NaHCO 3 as a buffer. The effect of ash on the growth of algae was related to the type of coal-fired combustion and the amount of ash. For one of the ash types tested, the algae growth rate actually increased at a low ash concentration. In this work, major technical hurdles in the use of algal scrubbing systems are being addressed with respect to major contaminants in coal-derived flue gases.