Removal of Nitrogen and Phosphorus from Domestic Wastewater by Microalgal Cultures

Domestic wastewater contains high concentrations of multiple organic and inorganic nutrient pollutants. When released without treatment, it can lead to a reduction in oxygen levels and eutrophication in water sources. Bioremediation utilizes the genetic and metabolic diversity of microorganisms in industrial processes, optimizing their biological capabilities. It is a promising method for approaching various contemporary issues such as climate change, remediation of contaminated environments, and the production of pharmaceutical, nutraceutical, or industrial molecules and biomass of interest. Microalgae, which are always associated with bacteria, can be used in bioreactors, treatment plants, or in-situ inoculations for wastewater remediation. Attached bacteria obtain oxidizable organic matter from the microalgae, which is released during photosynthesis. In turn, the bacteria provide factors that promote the growth of microalgae. Several studies have demonstrated the effectiveness of microalgae in the removal of nitrogen and phosphorus from wastewater. This chapter focuses on the removal of nitrogen and phosphorus from domestic wastewater using microalgae cultures from a metabolic perspective. These treatments can be carried out in open ponds, closed photobioreactors, or high-rate algal ponds (HRAP).