Avaliação multicritério para escolha de soluções individuais de tratamento de esgoto em zonas rurais.

Abstract

According to the 2010 IBGE census, approximately 928 thousand people live in rural areas, which are in a precarious situation with regard to basic sanitation. According to the SNIS in 2021, only eight percent of the rural population had sewage collection. Since these locations are commonly neglected and the actions taken do not meet the needs of the population. Thus, the use of individual sewage treatment systems appears as the main option for adapting the disposal of domestic effluents in rural and isolated areas, being an indispensable part of the search for universal service. This work sought to examine the application of multi-criteria procedures for selecting sewage treatment systems for single-family homes in Brazil. A methodology was developed based on the PROMETHE-II overclassification method, in which alternatives must be compared and categories of second criteria. The following systems were evaluated: (1) Septic tank and drain; (2) Septic tank and infiltration ditch; (3) Septic tank and banana tree circle; (4) Septic tank and Pantanal; (5) Green Trench; (6) Compact UASB reactor; (7) Septic tank biodigester. A literature review was developed that included an analysis of the main characteristics of the individual treatment systems considered, provided as a basis for subsequent evaluation and comparison of options. To define the weight of the evaluation criteria, an interview was carried out with a group of decision-makers and experts who are part of the development of municipal sanitation plans of TED no. 03/2019 with the Federal University of Campina Grande. The tool was tested and validated in seven different scenarios related to the challenge of decision-making in complex situations. It should be noted that the individual alternatives proven, in view of the judgments, the alternatives that performed best, in six scenarios, were the green septic tank and the biodigester septic tank, mainly due to their advantages in costs, operation and treatment efficiency. Only in scenario 5 the septic tank associated with the infiltration ditch, the circle of banana trees and the sinkhole were the best definitions, this is justified by the fact that the strategic ones have a greater dimension in this analysis.