Integrated valorization system for simultaneous high strength organic wastewater treatment and astaxanthin production...

High-strength organic wastewater, e.g., potato juice wastewater, exerts high stress on the environment. This study proposes an integrated system for simultaneous high-strength organic wastewater treatment and nutrients upcycling for astaxanthin production by the combination of anaerobic processes and microalgae (Haematococcus pluvialis) cultivation. The potato juice wastewater was pretreated by either acidification or methanation. The effluents of both pretreatments achieved higher biomass yields of H. pluvialis compared to cultivation in standard culture media (control). The high acetate and potassium concentrations of the acidification effluents resulted in significantly higher astaxanthin production (24.5-27.9 mg g^-1, 3 days) compared to the control (14.7 mg g^-1, 12 days) in a shorter period. The integrated system contributed to a final removal efficiency of 51.3-75.8%, 86.5-98.3%, and 69.4-83.4% for COD, phosphorus, and ammonia, respectively. This study presents a promising two-stage process for simultaneous efficient methane and astaxanthin production, as well as remediation of high-strength organic wastewater.