Optimizing Microalgae Cultivation and Wastewater Treatment in Large-Scale Offshore Photobioreactors
Scientists at Algae Systems LLC, USA have designed a novel approach to wastewater treatment using algae grown in modular, offshore photobioreactors. The experiment was carried out at the Algae Systems plant in 
Daphne AL, where the process was used to treat up to 50,000 gal/day of raw waste water.
A combination of algal nutrient uptake, aeration and dewatering via suspended air floatation removed 75% of total nitrogen, 93% of total phosphorus and 92% BOD from influent wastewater. Offshore photobioreactors contained polycultures of microalgae dominated by genus Chlorella, Cryptomonas and Scenedesmus.
The resulting biomass was suitable for production of fuel via hydrothermal liquefaction. Biomass production rates ranged from 3.5 to 22.7 g/m2/day during continuous operation.
