| Abstract | BACKGROUND: Microalgae cultivation in wastewaters is a potential remediation technology for converting residual nutrientsinto valuable biomass for biofuels, fertilizers, animal and aquaculture feeds, and bio-based chemicals. The objective of thisstudy was to determine the potential for microalgae phycoremediation of aquaculture and agriculture wastewaters for sustain-able production of nutrient-rich algal biomass.
RESULTS: Thirty-seven aquaculture and agriculture wastewaters were evaluated as growth media for two freshwater, chloro-phytic microalgae strains (Chlorella sorokinianaSMC14M andScenedesmussp. AMDD). Although nutrient levels and physico-chemical parameters of the wastewaters varied widely, phycoremediation efficiency of nitrogen and phosphorous was high(>70%) for a large majority of them, with both microalgae strains. Photobioreactor cultivation (300 L) ofC. sorokinianagrownonfinfish aquaculture wastewater (CA2) and standard growth medium (SGM) exhibited similar biomass production levels andnutritional compositions of moisture (4.9–5.0%), ash (5.9–6.1%), nitrogen (8.6–8.8%), protein (41.0–42.1%), lipid (8.6–8.8%),carbohydrate (38.3–39.3%) and gross energy (22.2–22.3 MJkg⁻¹) with highly similar fatty acid and amino acid profiles.
CONCLUSIONS: This study demonstrates that the use of freshwater microalgae to remediate various aquaculture and agricul-ture wastewaters, while producing valuable nutrient-rich biomass, is feasible. We have found that a particularfinfish aquacul-ture wastewater (CA2) contains all of the nutrients required for rapid microalgae growth, avoiding the need for expensivecommercial fertilizers. The biochemical composition ofC. sorokinianagrown on CA2 aquaculture wastewater has good poten-tial for use as a nutrient-rich ingredient for animal and aquaculture feeds, fertilizers products, biofuels and other applications,resulting in remediated water that could be reused. |
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