Simultaneous microalgal biomass production and CO2 fixation by cultivating Chlorella sp. GD with aquaculture wastewater and boiler flue gas

- Combined aquaculture wastewater and flue gas was applied for Chlorella sp. culture.
- Microalgal cultivation was used to reuse water resource and reduce CO2 emission.
- Aquaculture wastewater with nutrient addition was suitable for Chlorella sp. culture.
- Biomass productivity of Chlorella sp. aerated with boiler flue gas was 1.296 g L−1 d−1.
- CO2 fixation of Chlorella sp. aerated with boiler flue gas was 2.333 g L−1 d−1.

A microalgal strain, Chlorella sp. GD, cultivated in aquaculture wastewater (AW) aerated with boiler flue gas, was investigated. When AW from a grouper fish farm was supplemented with additional nutrients, the microalgal biomass productivity after 7 days of culture was 0.794 g L−1 d−1. CO2 fixation efficiencies of the microalgal strains aerated with 0.05, 0.1, 0.2, and 0.3 vvm of boiler flue gas (containing approximately 8% CO2) were 53, 51, 38, and 30%, respectively. When the microalgal strain was cultured with boiler flue gas in nutrient-added AW, biomass productivity increased to 0.892 g L−1 d−1. In semi-continuous cultures, average biomass productivities of the microalgal strain in 2-day, 3-day, and 4-day replacement cultures were 1.296, 0.985, and 0.944 g L−1 d−1, respectively. These results demonstrate the potential of using Chlorella sp. GD cultivations in AW aerated with boiler flue gas for reusing water resources, reducing CO2 emission, and producing microalgal biomass.

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