masterThesis
Tratabilidade de efluente kraft por processo biológico facultativo assistido com enzimas ligninolíticas
Fecha
2017-03-22Registro en:
MACHADO, Eliane Pereira. Tratabilidade de efluente kraft por processo biológico facultativo assistido com enzimas ligninolíticas. 2017. 113 f. Dissertação (Mestrado em Ciência e Tecnologia Ambiental) - Universidade Tecnológica Federal do Paraná, Curitiba, 2017.
Autor
Machado, Eliane Pereira
Resumen
The kraft process is the most used in the world for the production of pulp and paper. This process was done with high concentrations of organic matter and recalcitrant compounds, which can have a significant impact on the aquatic environment. In Brazil, the most widespread treatment for this effluent is as Facultative Aerated Lagoons (FALs). This type of treatment is efficient in the removal of biodegradable organic matter, however some contaminants persist because of its recalcitrance, attributing toxicity to the effluent even after treatment. The objective of this work was to evaluate the treatment of kraft effluent by biological process in the presence of commercial Laccase (NOVOZYM 51003®) and ligninolytic enzymes produced in the laboratory by extract of White Rot Fungi (WRF). An experimental study was carried out with the aerobic batch system to determine the effects of pH, temperature and commercial Laccase concentration, as well as the rapid batch tests to verify the effect of inoculation associated with commercial Laccase, the effect of Laccase/Mediator and the effect of Inactive commercial Laccase in the effluent treatment. We also study the performance of the commercial Laccase and the Enzymatic Extract of Trametes sp. (EET) in continuous flow, in lab scale FALs, under room temperature conditions, for 60 days in a constant Organic Load Rate (OLR). In a second phase of the experiment with FALs, a sudden increase in OLR was performed to verify the efficiency of shock systems. The factorial experiment showed that the use of commercial Laccase positively influences a lignin removal, color and spectral area, being more efficient at pH 4 and temperature of 37 ° C and 3.9 U mL-1 laccase. Batch tests show that an inoculation does not interfere with enzymatic activity and that a commercial enzyme is readily biodegraded within the system. The experiment with FALs at constant OLR of 0.2 kg COD m-3 d-1, showed that FAL with commercial Laccase removed 86%, 52%, 20% and 30% of BOD5,20, COD, Color and Lignin Compounds (LC), respectively with FAL with EET removed 90%, 50%, 2% and 20% of BOD5,20, COD, Color and CL, respectively. But the values of both FALs were not statistically different compared to their control. Also in the OLR of 0.2 kg COD m-3 d-1, the FAL with EET showed a 1% removal, which represents a reduction of the Total Phenolic Compound (TPC). The increase of OLR to 0.6 or 1.2 kg COD m-3d-1 does not negatively impact the efficiency of the FAL, leading to a weight increase in the removal of COD and TPC. A reduction of the BOD5,20/COD ratio caused a expressively more important shock them biodegradable organic matter overloads. Due to the effluent characteristics and conditions of use, the commercial Laccase had its activity reduced within the LAF system in 58% after 24 hours of contact. However, the FAL with EET it showed that, although diluted, the crude laccase present in the EET remained active and allowed to catalyze the removal of TPC present in the kraft pulp mill effluent, Due to the presence of other compounds Interacting with each other, mediating these reactions. This it seems expressively important, since the FAL used as control, absence of Laccase, promoted an increase of about 23% in the TPC content of the treated effluent.