The effect of salinity concentration on algal biomass production and nutrient removal from municipal wastewater by Dunaliella salina

Extensive amounts of organic and inorganic substances are discharged into the environment, and they have been ascribed to a number of anthropogenic activities including agriculture, industry, and domestic processes. Microalgae, as a promising alternative feedstock for bioenergy production, have advantages in the uptake of nutrients from wastewater for biomass production. This study assessed the feasibility of mass cultivation of microalgae in controlled environment tertiary treated municipal wastewater. Dunaliella salina (Dsalina) was selected for its high beta carotene generation capacity and being a halophilic species to protect our freshwater resources further in wastewater remediation. Nutrient analyses indicated that Dsalina can significantly remove nitrate, ammonia, and phosphorus from municipal wastewater in the range of 45% to 88%. Among all combinations studied, the optimal algal growth was observed at 30 ppt salinity level, with a 75% wastewater concentration (3:1 ratio of wastewater and saline water mixturethe - the growth medium). The findings concluded that Dsalina has great capacity for nutrient uptake while providing high-value bioproducts. It can therefore be recommended as a potential candidate species that could be used in wastewater treatment systems coupled with high-value bioproducts production.