Modelo de análise de risco aplicado a planos de segurança da água para consumo humano em comunidades rurais.

Abstract

In Brazil, access to safe water is hindered not only by climatic phenomena but also by deficiencies in public management, resulting in inequalities between rural and urban areas. The National Rural Sanitation Program emphasizes the importance of the Water Safety Plan (WSP) to ensure potable water in rural areas. However, the implementation faces technical, operational, and governance challenges, particularly in small systems and dispersed areas. Therefore, the aim of this study is to propose a risk analysis model for water safety based on Failure Mode and Effects Analysis (FMEA) and fuzzy logic as a tool for developing WSPs for systems and alternative water supply solutions in rural communities. Two rural communities in the state of Ceará were selected for the study. In the first stage, the hazards and dangerous events present in the water supply system and collective alternative water solutions of the selected communities were identified. Next, a Mamdani-type fuzzy model was constructed based on the input variables of the traditional FMEA (occurrence, severity, and detection). Fuzzy inference was divided into two phases to reduce the number of rules and obtain a more representative model. In the defuzzification phase, the center of gravity area (CGA) method was used, which converts fuzzy values into a real numerical value, used for prioritizing dangerous events. Finally, the model was validated through comparative analysis with the methodology suggested by the World Health Organization (WHO). The dangerous events identified in the communities were due to a lack of adequate infrastructure, operational and management failures, inadequate human activities, and adverse environmental conditions. It was possible to obtain descriptions of linguistic terms consistent with rural reality, which, combined with the use of triangular and trapezoidal membership functions, provided a clear and intuitive representation of the risks for the WSP. The application of the model in the selected water supply systems and solutions allowed for a more detailed and adjusted evaluation of the local reality through the Fuzzy-FMEA approach, solving the subjectivity associated with expert responses in risk assessment, as well as tie situations that occur with the traditional prioritization matrix methodology. When compared to the WHO suggested methodology, the model can support decision-making more effectively regarding the control measures needed to mitigate the risks associated with dangerous events.