Aplicação do biossurfactante de Bacillus methylotrophicus UCP 1616 como coletor no tratamento de águas oleosas em processos de flotação

Abstract

Activities related to the oil and electric energy sector are mainly responsible for the production of oily water and its disposal, requiring strategies for the treatment and separation of these residues. Dissolved Air Flotation (DAF) is one of the most used water-oil separation processes. This technology uses mostly chemical surfactants as collectors to enhance the separation of oil particles in suspension. As an alternative to synthetic and toxic surfactants, the use of biosurfactants has stood out for the treatment of industrial effluents, as they are biodegradable and have low toxicity. In view of the challenges exposed and the needs for development and improvement of known techniques, the present work presents an efficient solution using a biosurfactant as an alternative collector, produced by Bacillus methylotrophicus UCP 1616 in an economic culture medium composed of industrial waste associated with flotation technologies. Production was evaluated, stability in the face of a wide range of conditions (pH, temperature and salinity), chemical characterization (FTIR and 1H NMR) of the biotensoactive, toxicity to vegetable seeds and the application of the biotensoactive in the removal of oil in soils and waters as a bioremediation agent. After evaluating its properties, the biotensoactive was formulated commercially, through the addition of a preservative (potassium sorbate) and with heat treatment at 80 ° C. After formulation, samples of the biosurfactant were stored at room temperature for 180 days and their surfactant properties were tested. The B. methylotrophicus biosurfactant was applied in a bench scale FAD system and in a vertical Chamber of flotation by Induced Pre- Saturation (CPSI) as an alternative collector, being added to a synthetic oily effluent with 150 ppm of lubricating oil in water. A Central Rotational Composite Design (CCRD) was used to evaluate the influence of independent variables (effluent flow and formulated biosurfactant flow) on the oil removal efficiency in prototypes. Samples of the treated effluent were collected to evaluate the percentage of oil removal by spectrophotometry. According to the results obtained, the biosurfactant showed a reduction in the surface tension of the water from 71 mN / m to 29 mN / m and high stability under the conditions studied. The maximum concentration of biosurfactant reached was 10.0 g / l. The biomolecule was considered a lipopeptide based on the results of chemical characterization, demonstrated absence of toxicity and exhibited potential for the bioremediation of soil and water contaminated by oil derivatives. The formulated biosurfactant demonstrated stability in both conservation methods, with tolerance in environments with extreme conditions. The efficiency of the formulated biomolecule was demonstrated by the oil removal rate of 92% in the DAF prototype and 99% in CIPS. The results showed that the biosurfactant of B. methylotrophicus increases the efficiency of the flotation process, being able to assist in the mitigation and management of industrial effluents and contributing to the reduction of environmental pollution caused by oil-derived hydrocarbons.