Determinação das funções de pertinência dos índices de qualidade da água e de substâncias tóxicas e organolépticas

Abstract

Because the major concern existing with the water quality of rivers in the state of São Paulo, assessments are needed which use techniques efficient and easy interpretation by users. For a accurate and robust assessment of water quality is necessary to use techniques which involve a large number of parameters and their interactions. In this work, made up a mathematical model to evaluate of water quality taking into account various parameters used in general for the classification of water, such as indices defined by IAP(index of quality of raw water for public supply), IAV (index water quality for protection of aquatic life) and ISTO (index of toxic and organoleptic), besides the variables ecotoxicological, physical, hydrological, chemical and microbiological. Membership functions were developed for fuzzy models with the aim of obtaining a new method of describing the quality of water, allowing future assessments of water quality through a single index that considers all the parameters cited. Among the advantages of applying fuzzy logic, it is possible highlight its simplicity and low computational cost, in addition to reducing losses of information by their ability to raise levels of relevance for each class of geo-objects. The creation of membership functions analytically and also by implementing the computational in software Matlab ® was based on information from the Ministry of Health and such functions have proved adequate in relation to the observed data for future evaluation of any possible future situations of water quality.

Keywords

• Mathematical modeling
• Fuzzy logic
• Index of water quality