Aplicação da metodologia de avaliação semiquantitativa de riscos microbiológicos (ASqRM) associados à reutilização de efluentes de uma ete descentralizada estudo de caso em um condomínio residencial

Abstract

The practice of water reuse alleviates regional water pressures, which minimizes the use of potable water for less noble purposes, such as irrigating gardens and washing cars and sidewalks. In addition, it reduces conflicts over water use, increases sewage treatment rates, and encourages the development of technologies for improving the quality of treated effluents. However, despite being a topic that has been discussed since the 20th century, Brazil lacks specific national legislation that defines water quality standards for reuse, as well as incentives for reuse practices. This study applies the Semiquantitative Microbiological Risk Assessment Methodology (ASqRM), a safe method when it comes to non-potable reuse, to assess the risk associated with the reuse of treated effluent produced by a residential condominium located in Maceió, Alagoas, validating the quality of the treated effluent through the microbiological indicator Escherichia coli. Based on the concentration of the microbiological indicator related to the treatment technology used in the Sewage Treatment Plant (STP), exposure routes and receptors susceptible to it, the model equations are applied to calculate the hazard brought by the implementation of the reuse practice and the consequences associated with the damage and vulnerabilities of the exposed receptors. The hazard of the effluent associated with this work refers to the STP treatment method, being characterized as a hazard factor of 7. By evaluating the possible receptors present in the study area, a variation of 0.29 and 0.84 in their vulnerability was identified. In general, all the risks associated with the reuse of the effluent from the condominium were considered acceptable or negligible, except in one case in which the STP did not operate correctly, increasing the hazard factor to 9. Thus, ASqRM proved to be a good tool for decision-making regarding the practice of reuse. However, the need to implement complementary barriers in the practice of reuse is highlighted in order to prevent and reduce the damage and risks caused to recipients.