Utilization of Model Power Plant Flue Gas for Cultivation of Chlorella vulgaris and Scenedesmusobliquus: Effect of Gaseous Pollutants on Biomass Production and CO۲ Biofixation

Power plants are considered a major contributor to carbon dioxide emissions. Moreover, flue gas of power plants contains other compounds such as NOx and SOx that can affect growth rate of microalgae. Therefore, in this study the effect of CO۲ in different concentrations of ۰.۰۴%, ۵% and ۱۵%, NOx in ۱۰۰ppm and SOx in ۶۰ppm was investigated simultaneously on biomass production and carbon dioxide fixation of two industrially important microalgae, Chlorella vulgaris and Scenedesmus obliquus. At CO۲ concentrations of ۰.۰۴%, ۵% and ۱۵%, the maximum CO۲ fixation rate was ۰.۷۶۸, ۰.۷۳ and ۰.۶۹g/l/d for Chlorella vulgaris and ۰.۳۱۱, ۰.۵۳ and ۰.۲۱۲g/l/d for Scenedesmus obliquus, respectively. the results showed that at ۱۵% of CO۲, maximum CO۲ fixation rate (RCO۲) of Chlorella vulgaris was decreased from ۰.۶۹ to ۰.۶۵g/l/d by adding ۱۰۰ ppm of NOx to culture medium, also a reduction from ۰.۶۹ to ۰.۲۱۲g/l/d was observed when ۶۰ ppm of SOx was injected to CO۲ stream. However, In the case of Scendesmus obliquus, an increase in RCO۲ from ۰.۲۱۲ to ۰.۳۶ and ۰.۲۱۲ to ۰.۲۴g/l/d was achieved in the presence of the same amount of NOx and SOx, respectively. At the same culture conditions, Chlorella vulgaris shows higher fixation rate than Scendesmus obliquus. CO۲ fixation rate increasing by Scendesmus obliquus in the presence of acidic gases (NOx and SOx) shows that Scendesmus obliquus tends to grow in lower pH.

Keywords:

Flue gas , CO۲ Biofixation , Gaseous pollutant , Chlorella vulgaris , Scnedesmus obliquus