1. M.Sc., Professor, Dept. of Environmental Engineering, Federal Univ. of Triângulo Mineiro, Uberaba 38064-200, Brazil (corresponding author).
2. Professor, Dept. of Computing, Federal Univ. of Espírito Santo, Alegre 29500-000, Brazil.
3. Professor, Dept. of Environmental Engineering, Federal Univ. of Espírito Santo, Vitória 29075-910, Brazil.