Application of a Floating Membrane Algal Photobioreactor for Freshwater Aquaculture

As the global population grows, water and food demand also increase. The intensive aquaculture industry has helped to mitigate these problems. In order to make aquaculture sustainable, it is necessary to remove the abundant nutrients produced by fish in the water. In this study, the role of the microalga of Chlorella vulgaris in the Isolated Cultivation of Algal Resources Utilizing Selectivity (ICARUS) membrane photobioreactor was evaluated for nutrient control in the aquaculture system. The production of algal biomass, the removal rate of nutrients, and the impact of microalgae on cultured organisms were monitored during the operation of aquaculture systems. At the end of the experiment, the yield of algae in ICARUS was approximately 344 ± 11.3 mg / L. Compared to the control groups, this production of algae is considered to be low. Likely factors were insufficient indoor light intensity, membrane fouling limiting the mass transfer of nutrients, and improvements still needed for the overall ICARUS prototype design. However, ICARUS can efficiently prevent algae from contamination, and provide pure harvest production for food supplement. It was observed that algae have the ability to help stabilize pH and increase dissolved oxygen for the system. However, in high-density, mixed systems, algae may cause physical damage to fish (e.g., clogging of gills). The high ammonia concentrations produced by fish could be controlled by Chlorella vulgaris since this species of algae prefers ammonia to nitrate. In conjunction with algal growth, aquaculture systems concentration of ammonia was maintained at 0.90±0.16 mg/L. The integration of ICARUS is not only a potentially sustainable option for aquaculture, but also a multipurpose tool for other types of wastewater treatment. An economic analysis for scale-up of the ICARUS system was performed. In summary, this study aimed to develop a new commercial ICARUS photobioreactor which can serve for different types of wastewater systems with a high algal production efficiency and economic benefits