Advanced treatment of food processing effluent by indigenous microalgae-bacteria consortia: Population dynamics and enhanced nitrogen uptake

The potential of indigenous microalgae-bacteria consortia (IMBC) to recover nutrients from food processing effluents (FPE) supports the basis for advanced effluent polishing and value-added biomass generation. In this study, the effluent polishing potential of an FPE-borne IMBC treating FPE and synthetic wastewater (SWW) was investigated regarding nutrient, coliform bacteria, and chemical oxygen demand (COD) removal as well as the IMBC species evolution, and pigment production. Species evolution and diversity of the IMBC in FPE and SWW were influenced by nitrogen levels (3.83 mg/L and 32.61 mg/L NH4+, respectively). More blue-green microalgae were observed in SWW (0.96 mg/L phycocyanin) whilst diatoms dominated in FPE (0.05 mg/L phycocyanin). Total coliform bacteria removal influenced COD reduction and this had a significant effect on dissolved oxygen production. The study offers new insights into the feasibility of using IMBC biofilm for advanced FPE polishing and nutrient recovery (0.98 mg/L NH4+, 0.85 mg/L PO43−, 0.84 mg/L COD, 3.2 g/L protein, and 2.8 g/L carbohydrates), demonstrating that it is possible to use IMBC biofilm for post-treatment of FPE, removing the residual N and P to prevent eutrophication.