Eficiência de caixas separadoras de gordura utilizando efluentes industriais

Abstract

This study presents the analysis of performance of two grease traps. Observing the dimensions specified in NBR - 8160, which the minimum volume results in a low hydraulic retention time (HRT), between 3 and 60 s, whereas the recommended time is about 3 minutes. Was analyzed the parameters of COD, pH, Temperature, O&G and Settleable Solids in two grease traps, which were subjected to three types of effluents, and also from distinct nature: from a gas station, from an auto repair shop and from a place to wash vehicles. The two boxes chosen for the study were: a small type of pre-made grease trap popularly used with 19 L of volume, and another one proposed with a larger design, with 54 L, seeking an increase in surface area. Were carried out a total of thirteen test batch. The samples for characterization were made from the raw effluent and after one and two hours inside the boxes. The average efficiencies of COD reduction in proposed box ranged from 1.45% (for the effluent from a gas station) and 26.20% (effluent from automotive work-shop), while for the prefabricated box this group was 7.34% (gas station) to 13.57% (machine shop). For oils and greases, efficiencies were 73,7% and 74.4%, respectively, for the box designed and box prefab. There was no significant difference between the efficiencies of the two boxes according to the tests of Anova and Tukey.