Cultivation of marine microalgae using shale gas flowback water and anaerobic digestion effluent as the cultivation medium

The potential of shale gas flowback water and anaerobic digestion (AD) effluent to reduce the water and nutrient requirements for marine microalgae cultivation was evaluated with the following strains: Nannochloropsis salina, Dunaliella tertiolecta, and Dunaliella salina. N. salina and D. tertiolecta achieved the highest biomass productivity in the medium composed of flowback water and AD effluent (6% v/v). Growth in the above unsterilized medium was found to be comparable to that in sterilized commercial media with similar initial inorganic nitrogen concentrations, salinity, and pH levels. Specific growth rates of 0.293 and 0.349 day−1 and average biomass productivities of 225 and 275 mg L−1 day−1 were obtained for N. salina and D. tertiolecta, respectively. The lipid content and fatty acid profile of both strains in the medium were also comparable to those obtained with commercial nutrients and salts.