(105a) Assessment of the Presence of Polychlorinated Dibenzodioxins and Furans (PCDD/Fs) in Flue Gas on Microalgal Growth & Nutritional Value

Microalgae is known to be one of the most sustainable food sources for the future and have gained much attention as a food supplement and replacement. They can be “harvested” in large quantities perennially and can minimally provide three-fold higher protein yield than plant-based protein sources, including wheat, pulse legumes, and soybean. Their growth rate can be increased by feeding high volumes of CO₂ to promote photosynthesis. Waste-to-Energy (WTE) incinerators are the most concentrated and readily available source of CO₂ (~12%) and can be used for microalgae cultivation. Microalgae has been reported to capture 1.83 kg of CO₂ / kg biomass produced, showing promising prospect in carbon fixation. The biomass produced can then be fed into various manufacturing processes. WTE incinerator power plants utilize municipal solid waste as a fuel source for power generation, reducing the dependence on fossil fuels, while diverting wastes from landfills, indirectly reducing CH₄ emission. However, incineration of such waste, which often includes significant quantity of plastics and other halogenated compounds, will produce PCDD/Fs. Therefore, to economically use CO₂ from WTE flue gas for microalgae production, assessment of the presence of the dioxins on the microalgae is an important consideration. Chlorella sp. (a freshwater species) is chosen for the work due to its extremely high protein content (50-60%). To facilitate the understanding, Chlorella is exposed to different concentrations of the dioxins, followed by the analysis of change in several physiological parameters such as cell growth, cell morphology, nutritional content of protein (amino acid profiles), lipids and carbohydrates as well as Chlorophyll a. These measurements would then be used as the evaluation criteria to provide a more comprehensive view on what steps need to be included or improved for the enhanced scrubbing of the PCDD/Fs from the incinerator flue gas such that a sustainable food production cycle from waste can be generated, creating a self-sustaining ecosystem.