Abstract
A common practice adopted by several Brazilian companies is to collect residual frying oil and to use it for detergent or soap production. This practice, however, is challenging for the industry, since the use of waste oil generates a heterogenous effluent with high turbidity and containing numerous suspended particles. In this context, the flotation process has proven to be quite efficient for the treatment of this type of effluent, with the capability of removing a larger amount of oil in comparison to other methods. The development and use of microbiological surfactants may enhance even more the efficiency of this technology. These biological molecules also have several advantages over synthetic surfactants such as higher biodegradability, less toxicity, better environmental compatibility and can be synthesized from renewable feedstocks. The aim of the present study was to evaluate the separation efficiency of oil fraction from the effluent from the soap and detergent industry (ASA INDUSTRIA E COMÉRCIO LTDA, Recife – PE, Brazil) using a bench-scale DAF prototype with the addition of two different forms of a biosurfactant as alternative collectors. Biosurfactants was obtained from the bacterium Pseudomonas cepacia CCT 6659 and applied to the DAF system in both crude and isolated forms. The results demonstrated that the DAF-biosurfactant system increased oil separation efficiency of the DAF process from 69.49% (using only microbubbles) to 89.83 and 86.44% using the isolated and crude biosurfactant, respectively. In addition, there was also a turbidity reduction of the effluent, based on Brazilian Resolution CONAMA 430/2011. Therefore, the biosurfactant from P. cepacia in its isolated form was selected as the more promising product for the treatment of effluent from soap and detergent industry plant.
