Modelling and Optimization of Combined Wastewater Treatment and CO2 Bio-fixation in a Batch Algal Photobioreactor

The research focuses on investigation and optimization (using Box Behnken design) of the key parameters of CO2 gas concentration, light intensity, temperature, feedwater nutrient concentration, and wastewater origin (municipal primary and secondary, and petroleum industry) on photobioreactor algal growth parameters. A mathematical model is provided for predicting algal growth. Finally, the influence of light wavelength on algal growth is investigated. The outcomes can be used to inform design and operation of large-scale algal cultivation systems

A mathematical model for carbon fixation and nutrient removal by an algal photobioreactor

A comprehensive mathematical modeling method for Chlorella vulgaris (Cv) has been developed to assess the influence of nutrient concentration (total nitrogen TN= 28–207 and total phosphorus TP= 6–8 mg L−1) and irradiation intensity (I = 100–250 μE) at feed gas CO2 concentrations (Cc,g) of 0.04-5%. The model encompasses gas-to-liquid mass transfer, algal uptake of carbon dioxide (Cd), nutrient removal efficiency (RE for TN and TP), and the growth biokinetics of Cv with reference to the specific growth rate µ in d−1.The model was validated using experimental data on the Cv species growth in an externally illuminated photobioreactor (PBR). The fitted parameters of the model were found to be in good agreement with experimental data obtained over the range of cultivation conditions explored. The mathematical model accurately reproduced the dynamic profiles of the algal biomass and nutrient (TN and TP) concentrations, and light attenuation at different input Cc,g values. The proposed model may therefore be used for predicting algal growth and nutrient RE for this algal species, permitting both process optimization and scale-up