Otimização do tratamento de águas oleosas com alto grau de emulsificação utilizando biossurfactante e flotação por ar dissolvido (fad).

Abstract

Residual Frying Oil (RFO) is part of one of the waste generated daily in households, industries and voluntary delivery points (public and mixed-economy companies). The uncontrolled disposal of residues of frying oils, in sinks or dumped directly into bodies of water, entails a series of environmental damages, such as obstruction of pipes in sewage systems and increased costs of treatment processes, in addition to Increased pollution. The collection and reuse of these waste oils prevents them from being disposed of inappropriately and benefits the environment. The percentage recovery of residual oil from fried foods depends to a large extent on the washing operations. These operations are also responsible for the effective separation of the organic and aqueous phases from the emulsions generated so as to obtain a lower possible oil content in the aqueous phase, while the oil can still be used for reuse in the soap and detergent production processes. In this work, actions were taken to improve the operational conditions to improve the process of chemical washing of the ORF by cleaning products industries, in order to generate an adequate effluent for subsequent physical-chemical treatment by Dissolved Air Flotation (DAF). After conditioning, the OFR collection vessel was rinsed with steam and received addition of chemical reagents (HCLO3, NaOH and NaCl). The material was then treated through DAF, with a biosurfactant acting as a biodegradable manifold, in a laboratory scale prototype operating in continuous mode. The experiments were performed according to a Central Composite Designs (CCD) of type 22. As factors, the ratio between the effluent flow to be treated and the biosurfactant flow rate (X1) was used, and the ratio of the air flow to the effluent flow recirculated to produce the microbubbles (X2). As a response variable the water-oil separation efficiency was used. A maximum separation efficiency of 98.0% for X1 and X2 values equal to 1.0.103 and 1.05.104, respectively.