The economic and environmental value of microalgae has attracted much attention of the world. Microalgae are promising feedstock of biofuels as well as nutritious food for human and animals. Meanwhile, microalgae cultivation offers alternative means for carbon dioxide (CO₂) removal from the atmosphere and nitrogen and phosphorous removal from wastewater. Despite the achievements in understanding the biological features of microalgae and design of the reactors for microalgae cultivation, there is still a lack of systematic process design for integrating microalgae cultivation with gas and wastewater treatment.

In this study, an integrated system for microalgae production and processing has been conceptually designed. This system adopts the design of a novel reactor design and couples CO...[ Read more ]

The economic and environmental value of microalgae has attracted much attention of the world. Microalgae are promising feedstock of biofuels as well as nutritious food for human and animals. Meanwhile, microalgae cultivation offers alternative means for carbon dioxide (CO₂) removal from the atmosphere and nitrogen and phosphorous removal from wastewater. Despite the achievements in understanding the biological features of microalgae and design of the reactors for microalgae cultivation, there is still a lack of systematic process design for integrating microalgae cultivation with gas and wastewater treatment.

In this study, an integrated system for microalgae production and processing has been conceptually designed. This system adopts the design of a novel reactor design and couples CO₂ consumption and wastewater treatment with the cultivation and processing of Chlorella sp. To start with, the effects of key operating parameters on the growth, CO₂ consumption and O₂ generation performance of the microalgae were studied. Since solar illumination was to be used in the integrated system as the light source, the microalgae growth rate and gas treatment performance under simulated diurnal cycles were also determined using an experimental simulation method. To fully use the inorganic nutrients in the wastewater streams and improve the growth rate of microalgae, a framework for synthesizing and optimizing a wastewater conditioning plan was developed and demonstrated with a reverse osmosis concentrate. Then, a filtration photobioreactor (FPBR) was designed to reduce the cost of biomass harvest as well as suit the utilization of different types of CO₂ polluted gas and wastewater streams. The operating conditions of the FPBR for cultivating Chlorella sp. were also selected. Finally, heuristics for the system integration were proposed. The benefits of system integration were determined and different options of system integration were compared in the case studies.