A sustainable resource recovery approach through micro-algae integrated brine management in minimal liquid discharge system

Nutrients, heavy metals, micropollutants, and organic contaminants are all present in the minimal liquid discharge (MLD) discharge water as the MLD is designed to recover 95 % of the water from the wastewater, and the remaining 5 % is disposed of through conventional or advanced disposal strategies. The rejected brine cannot be utilized or discarded without eliminating the impurities. Microalgae cultivation in brine medium has been extensively researched for potential in the utilization of nutrients in the medium for its growth, and the harvested biomass can be beneficial and can become one of the efficient brine management strategies. The microalgae technique is considered sustainable and ecologically friendly compared to other brine management strategies because it generates zero secondary pollutants and provides income through biomass valorization. This review investigates the characteristics of brine from various MLD sectors; Tolerance of microalgae species in brine medium; Microalgae bioremediation and the mechanism adapted for the removal of nutrients, pollutants and other contaminants from the brine; Case studies that implemented microalgae-based brine management; and sloping microalgae solar evaporation pond system. Most significantly, the waste can be recovered as value-added bioproducts for the various sectors fulfilling the Sustainable Development Goals through microalgae brine management.