Biosolids in Brazil: National Scenario, Legal Aspects, and Comparison with Average Parameters Obtained in Sewage Treatment Plants – A Review

Abstract

The production of biosolids in Brazil has increased due to the expansion of sewage treatment plants, making these materials a sustainable alternative for agricultural use. Composed of high organic matter and nutrients such as nitrogen, phosphorus, calcium and magnesium, biosolids have the potential to improve the physical, chemical and biological properties of tropical soils, contributing to greater fertility, water retention and microbial activity. National literature demonstrates that these materials can partially replace mineral fertilizers and assist in the recovery of degraded areas. On the other hand, the presence of contaminants still represents a challenge. Heavy metals such as Cd, Pb, Ni and Hg generally appear in low concentrations, while Cu and Zn tend to approach the maximum limits established by CONAMA Resolution No. 498/2020. Regarding pathogens, the efficiency of sanitization depends on the treatment method employed. Emerging organic pollutants, including pharmaceuticals and hormones, have been detected, but still lack specific regulations in Brazil. Thus, although biosolids present high agronomic potential, their safe use requires adequate monitoring, improvement in controlling the origin of sewage and advances in legislation, especially regarding emerging organic pollutants.