One Strain Solving Two Problems: Removing Harmful Nutrients in Wastewater and Harvesting Lipids for Biofuel with Immobilized Microalgae
Kirthana and Sarah completing a REM validation test


algae beads
wastewater treatment



Microalgae is an applicable solution for the removal of nutrient contaminants (such as nitrogen and phosphorus) that pollute bodies of water. While microalgae can remediate these contaminants when implemented in wastewater treatment, the cultivation of the microalgae is costly. To address this economic obstacle, we maximized the cost-effectiveness and removal efficiency of the microalgae treatment with immobilized Chlorella pyrenoidosa and Scenedesmus quadricauda, highly efficient and adaptable strains, and the addition of a plant hormone. After nutrient removal, we used the remaining microalgae content to address an additional problem: emissions from conventional transportation fuel. The resulting increase in biomass and lipid yield from the debeaded microalgae has the potential to create a biofuel alternative, and hence, decrease the cost of wastewater treatment. The data we achieved for nitrate-N was promising; the nitrate-N levels in full-strength wastewater decreased from 35.5 mg/L to 3.8 mg/L in 7 days and the nitrate-N content in 25% wastewater (with the same beads/flask and zeatin concentration) decreased from 9.9 mg.L to 1.4 mg/L in 2 days. While the ammonium-N did not reach nutrient starvation, the full-strength wastewater removed ammonium-N from 26.6 mg/L to 5.7 mg/L, reaching near-starvation levels (< 2 mg/L). The phosphorus removal data is still being processed. The lipid yield data was inconclusive due to the samples not reaching nutrient starvation levels (2 mg/L of nitrate-N, 2 mg/L ammonium-N).



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