APPLICATION OF FUZZY LOGIC TO THE STREETERPHELPS MODEL TO ANALYZE THE CONTAMINATION RISK IN RIVERS THAT RECEIVE SPECIFIC DISCHARGE SOURCES

Abstract

A mathematical model based on the Fuzzy Streeter-Phelps equations was developed to analyze the river contamination risk receiving punctual source release. The Streeter-Phelps model was transformed into a differential fuzzy model, with a closed and bounded interval having lower and upper bounds well defined, but with unknown distribution information. For the analysis, it was defined an scenario in which punctual BOD loads were released with different concentration values, ranging from 100 through 500 mg / L. The concentrations, as well as the behavior of risk of the BOD, DO deficit and DO was verified. It was observed that any change in the BOD concentration released influenced the mass dilution in the system in such a way as the bigger is the released; the smaller is the dilution.

Key words: Fuzzy Set Theory; Risk Analysis; Streeter-Phelps Model.