Performance Evaluation of Chlorococcum sp. in Various Photobioreactor Designs: Impact on Biomass Production and Nutrient Removal

This study examines the influence of photobioreactor (PBR) configuration on the cultivation performance of Chlorococcum sp. using aquaculture wastewater as the growth medium. Four systems were compared: horizontal without aeration (H-Plain), horizontal with aeration (H-Aerated), vertical with aeration (V-Aerated), and vertical with aeration and red LED illumination (V-LED). Over 14 days, the V-LED system achieved the highest biomass concentration (0.50 g L−1) and volumetric productivity (0.063 g L−1 day−1), accompanied by nitrate and phosphate removals of 94% and 55.6%, respectively. Statistical analysis (ANOVA, p < 0.05) confirmed significant differences among configurations, demonstrating that light quality and aeration act synergistically to enhance growth and nutrient assimilation. While aeration improved CO2 transfer and mixing, it was insufficient without adequate photon delivery. Conversely, red LED illumination mitigated photolimitation in vertical systems, promoting efficient photosynthesis and nutrient uptake. Energy assessment revealed that V-LED offered the highest productivity in expense of power input (1.08 kWh day−1). These findings highlight the critical role of integrated PBR design, emphasizing that optimal combinations of geometry, aeration, and spectral lighting as keys to achieving high biomass yields and efficient nutrient removal in sustainable microalgae-based wastewater treatment systems.