Microalgal Biomass

Wastewater treatment is a major environmental and health challenge, given the growing presence of pollutants of domestic, agricultural, and industrial origin. These effluents contain a wide range of contaminants such as nutrients (nitrogen, phosphorus, carbon), heavy metals (HMs), dyes, and pharmaceutical residues, all of which are liable to disrupt aquatic ecosystems and threaten public health. In this context, the use of microalgal biomass offers an innovative, economical, and ecologically sustainable method for eliminating these pollutants. Thanks to its photosynthetic capacity, rapid growth, and large, exchange-promoting specific surface area, microalgal biomass can effectively remove conventional pollutants (nitrogen, phosphorus, CO₂), as well as a wide range of industrial pollutants, including HMs, synthetic dyes, and pharmaceutical substances. Removal of these contaminants relies on several mechanisms, including assimilation for nutrients, and biosorption, bioaccumulation, and biodegradation for organic and metallic pollutants. This chapter highlights the potential of microalgae as a biotechnological tool for wastewater depollution, detailing the biological, biochemical, and physico-chemical mechanisms involved in the removal of different types of pollutants.