Comprehensive assessment of the microalgae-nitrifying bacteria competition in microalgae-based wastewater treatment systems: Relevant factors, evaluation methods and control strategies

Abstract

[EN] Due to their capacity to assimilate carbon dioxide and nutrients, microalgae-based cultivation systems have emerged as a green solution for intensive wastewater treatment. However, when large concentrations of ammonium are present the competition between microalgae and ammonium-oxidising bacteria plays a significant role. Microalgae use ammonium to synthesise proteins, photosynthetic pigments and nucleic acids, while ammonium-oxidising bacteria use it as a source of electrons and oxidise it to nitrite.Several authors have studied the isolated factors that influence microalgae-nitrifying bacteria competition, although a comprehensive analysis of this interesting topic is still lacking. This review makes an overall assessment of the competition between microalgae and ammonium-oxidising bacteriafor ammonium uptake, focusing on: I) factors that influence the competition; II) methods of measuring the activity and concentrations of microalgae and nitrifying bacteria; III) useful strategies to control nitrification to improve the performance of microalgae-based wastewater treatment systems.