Fig. 6. Effect of recycling of post-harvested spent water on the harvesting efficiency, biomass productivity and urea recovery for the growth of Chlorella sp. FC2 flocculated by FeSO4. Panel A: the FC2 cells were grown in a 5 L photobioreactor, followed by biomass harvesting with an F/X ratio of 2.5. Six consecutive batches of cultivation were performed (one control batch (C), followed by five RWHC batches (1–5)). Panel B: the FC2 cells were grown in a 5 L photobioreactor, followed by biomass harvesting with an F/X ratio of 1.5. Three consecutive batches of cultivation were performed (one control batch (C), followed by two RWNFC batches (1–2)). Panel C: the FC2 cells were grown in a 350 L open raceway pond, followed by biomass harvesting with an F/X ratio of 1.5. Two consecutive batches of cultivation were performed (one control batch (C), followed by one RWNFC batch (1)). The letters on the bar graphs represent the significant difference between the harvesting efficiency, biomass productivity, and urea recovery obtained from harvesting microalgal biomass using FeSO4 analyzed using the one-way analysis of variance based on Tukey's method. Harvesting efficiency, biomass productivity and urea recovery that do not share a common letter are significantly different.
