Microalgae as a solution for the recovery of nutrients from high-load sanitary wastewater

Abstract

Today's sanitation systems imply devaluation of waste, loss of nutrients, waste of water and emission of pollutant waste in the environment. It is known that the agricultural sector depends on the use of synthetic fertilizers for the global food production. However, this sector has been under great pressure due to the water crisis and the future shortage of phosphorus. In addition, the new concept of sanitation aims at the maximum recovery of energy and resources of wastewater, minimizing the use of drinking water and emissions of micropollutants. In this context, this project aims at the development and improvement of sanitary sewage treatment technologies that allow the transition to a circular economy and bring environmental, economic and social benefits. Therefore, a treatment process comprised of an anaerobic system and microalgae cultivation will be evaluated. Moreover, the final effluent quality, methane production and algal biomass will be monitored. The use of natural coagulants will be studied for the separation of the algal biomass by coagulation / flocculation. The resulting algal biomass will be evaluated for its biofertilizer quality and viability in Amaranthus cruentus cultivation. Removal of micropollutants, heavy metals and human pathogens will also be evaluated throughout the system to ensure final effluent quality and algal biomass suitable for reuse. Finally, the sustainability analysis of the process will be carried out, considering the different scenarios for algae biomass recovery. With the suggested treatment system the nutrients, energy and water cycles will be closed in a sustainable way, while we produce a valuable product of algal biomass. (AU)