Caracterização do efluente gerado no campus Poços de Caldas da Universidade Federal de Alfenas

Abstract

This work aimed to characterize the effluent generated at the Poços de Caldas campus of UNIFAL-MG, to statistically analyse how the effluent characteristics are influenced by several variables and to define ​​per capita loadings. The laboratory analyses were done under the methods described in the Standard Methods for the Examination of Water and Wastewater were used to determine chemical oxygen demand (COD), pH, chlorides, conductivity, ammoniacal nitrogen, total solids (fixed and volatile) and suspended solids (fixed and volatile). In addition, a conductivitimeter was used to determine dissolved solids. The sewage flow on campus was estimated by measuring water consumption. Using generated data statistical analyses were taking using analysis of variance, mean comparison tests, T-tests and correlation trests.Results shows that COD and dissolved solids vary according to the days of the week, whereas pH, chloride and conductivity do not suffer this influence. It was also verified that there are no differences between the mean values ​​of the pH of the school and and this one of vacation period. COD, chloride and conductivity have statistically lower means in vacations than means in school days. pH, COD, total solids (fixed and volatile) and suspended solids (fixed and volatile) do not have statistically different means throughout the hours of the day. Correlation tests have shown that the academic population does not directly interfere with the pH and concentrations of COD, total solids (fixed and volatile) and suspended solids (fixed and volatile), but population interferes with the amount of water consumed on campus. In addition, the number of meals served can interfere with some characteristics. Considering all the analyses, the means found were (in mg / l) COD: 625.38 ± 347.30, total solids: 507.60 ± 207.30, total volatile solids: 311.90 ± 161.10, total fixed solid: 205.00 ± 120.50, volatile suspended solids: 102.80 ± 82.90, fixed suspended solids: 24.60 ± 0.43, ammoniacal nitrogen: 9.30 ± 4.99, dissolved solids: 399 , 05 ± 172.13, chloride: 189.41 ± 78.09. For the pH the mean was 7.07 ± 0.59 and for conductivity 787.89 ± 307.58 μS / cm. The estimated volume of effluent generation on campus was 9.82 m³ / day. The determination of the per capita load of each analysed parameter was lower than the reference values found in the literature for domestic sewage. This result reflects the importance of the characterization of the effluent for different generating sources, aiming at the best determination of the treatment to be used in each case.