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

Abstract

Summary 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 (D salina) 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 D salina 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 mixture—the growth medium). The findings concluded that D salina 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.

The Influence of Microalgae Addition as Co-Substrate in Anaerobic Digestion Processes

“…Among all combinations studied, optimal algal growth was observed at 30 ppt salinity level, with a 75% wastewater concentration (3:1 ratio of wastewater and saline water mixture, which is the growth medium). These findings concluded that D. salina has great capacity for nutrient uptake while providing high-value bioproducts [60].…”

“…A very recent study assessed the feasibility of the cultivation of D. salina in controlled environment tertiary-treated municipal wastewater [60]. D. salina was selected for its high β-carotene generation capacity and for being a halophilic species to protect our fresh water resources further through wastewater remediation.…”

Effects of salinity, pH and growth phase on the protein productivity by Dunaliella salina

“…The optimal salinity for D. salina found in this study is higher compared with other studies on both D. salina and other Dunaliella species. When cultivated at 0.5 mol L −1 NaCl salinity mixed with municipal wastewater, D. salina showed the highest biomass production . For Dunaliella sp.…”

“…When cultivated at 0.5 mol L −1 NaCl salinity mixed with municipal wastewater, D. salina showed the highest biomass production. 33 For Dunaliella sp. isolated from the South China Sea, the optimal salinities for cultivation are 0.5 and 0.9 mol L −1 , while at 0.9 mol L −1 salinity the microalga accumulated the highest protein content of around 50% during the stationary phase.…”

Application of Microalgal Stress Responses in Industrial Microalgal Production Systems

“…Mahsa et al have reported that the total biomass and protein concentrations of marine Spirulina platensis were observed under blue light, at around 100 µmol photons m −2 s −1 of 13.4 and 9.0 g L −1 , respectively. However, the highest phosphate and ammonium removal were about 145 and 218 mg L −1 under purple light, at around 100 µmol photons m −2 s −1 , respectively [97]. Results showed that light intensity and wavelength, combined with semi-batch cultivation, can be designed to achieve the highest biomass and production, as well as to maximize the removal of phosphorous and ammonium.…”