Assessment and modeling of microalgae growth considering the effects OF CO2, nutrients, dissolved organic carbon and solar irradiation

Abstract

The present study assesses and models the growth of microalgae during the combined processes of concurrent eliminations of CO2 from off-gas and nutrients from wastewater. The growth of single (Spirulina platensis, SP.PL) and mixed (mixed indigenous microalgae, MIMA) algae strains was tested in a pilot plant under natural conditions. The specific growth rate (?), biomass production (Pbio), CO2 biofixation rate (RCO2), and contaminate (organic matter and nutrient) reductions were investigated in response to the changes in concentration of CO2, nutrient and organic matters as well as solar irradiation. A mathematical model that incorporates the effect of growth variables: organic matter (COD), total inorganic nitrogen (TIN), total phosphate (TP), solar irradiation and dissolved CO2 was developed to predict the strains growth rate. The maximum value of ? for single strain was determined to occur at 40 mg COD/L, 20 mg-N/L, 8.9 mg-P/L, 12% CO2 (v/v) and 7.45 ?E/m2.s. MIMA showed a maximum value of ? at 55 mg COD/L, 17 mg-N/L, 10 mg-P/L, 17% CO2 and 8.45 ?E/m2.s. The predicted growth rates confirmed the ability of the model to match experimental data. Microalgae can be successfully used in sustainable CO2 capturing and wastewater treatment technology. - 2019 Elsevier Ltd