Uso agrícola de biossólido gerado a partir de um reator UASB tratando esgoto doméstico: uma análise de riscos microbiológicos para os trabalhadores rurais

Abstract

With the increase in population and the use of water in domestic and industrial activities, the growth of effluent generation around the world is remarkable. The effluents for the removal of substances and treatment mechanisms of consistent quality and quality, called the quantity of sewage. After proper treatment, sewage sludge is transformed into a new material, biosolids, with great potential for agricultural use, due to its water and soil nutrition properties. The use of these agricultural by-products from Effluent Treatment Stations (ETSs) is an alternative for final provision, however, the health risk associated with the presence of pathogens is an obstacle to this practice. The laws that regulate the application and use of biosolids are sometimes very restrictive, and do not take into account the risk assessment. In this, the Quantitative Microbial Risk Assessment (QMRA) is a mathematical tool that can be used to calculate the risks associated with different pathogens in different risk exposure scenarios. Thus, this work aims to evaluate the microbiological risks due to the use of sludge and biosolids in the soil, for agricultural use, using the QMRA for different exposure scenarios, where agricultural workers both perform the application in the biosolid in the biosolid in the planting of plantation, how to carry out the management of these biosolids in the cultures of carrots and lettuce, and having Ascaris lumbricoides as a target microorganism. Secondary data will be used for microbiological characterization of sewage sludge and ETS biosolids, for the application of QMRA, obtained from the literature review. The QMRA methodology involves four steps that facilitate, namely: (i Hazard identification / problem formulation; (ii) Exposure assessment; (iii) Dose-response analysis and (iv) Risk characterization. confronted with the tolerable risks by the World Health Organization (1.2x10-4 pppy - per person per year). The results will also be confronted with the Brazilian standards and adopted for the application of biosolids in the soil. According to the data presented, all exposure scenarios resulted in risk, above those presented by WHO, that is 1.2x10 -4 pppy. It is worth mentioning the importance of sanitizing the sludge from a UASB reactor, which only passed through a drying bed, before agricultural use.