Microalgae cultivated in previously treated wastewater as a fertilizer in Amaranthus cruentus L.

• Grant number: 20/06459-9
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: October 01, 2020
• End date: March 30, 2022
• Field of knowledge: Biological Sciences - Botany - Pant Physiology
• Principal Investigator: Gustavo Henrique Ribeiro da Silva
• Grantee: Elisa Teófilo Ferreira
• Host Institution: Faculdade de Engenharia (FE). Universidade Estadual Paulista (UNESP). Campus de Bauru. Bauru , SP, Brazil

Abstract

Currently, it is observed that the standards of sanitary sewage treatment and agricultural fertilization do not meet the needs of a population in constant growth, who have acquired new lifestyles and consumption habits. To keep up with these advances, new methods must be proposed. The sanitation systems used on a large scale do not have means of recovering nutrients, they need large amounts of water and are not efficient in the removal of residues, emitting polluting loads in the destination effluents, which is one of the factors that contribute to the eutrophication of water bodies. Another factor contributing to the eutrophication of water bodies is the chemical fertilization used primarily in agriculture, a practice that is harmful to the environment and increasingly unsustainable due to the lack of phosphorus reserves and increasing costs. Since the agricultural sector depends on means of fertilization to maintain its large-scale production, new methods must be proposed. At the same time, sewage treatment systems need alternatives to recover their nutrients. In this way, the present project aims to analyze the effectiveness of native microalgae grown in wastewater previously treated anaerobically, an alternative for depollution and recovery of nutrients, as an organic fertilizer in the growth of Amaranthus cruentus L., a vegetable of rapid growth cycle and of economic interest. In order to elucidate the effectiveness of the fertilizer, gas exchanges, photosynthetic pigments, growth, biomass production in the aerial part and mineral content of the leaves will be analyzed. This creates an alternative to fertilization with benefits for both farmers and the environment and gives a destination of the nutrients recovered from microalgae-based treatment,, enabling the closure of the nutrient cycle, contributing to a circular economy.