ABSTRACT
Abstract The textile industry demonstrates a polluting potential from the planting of cotton to the release of wastewater. The presence of dyes in water bodies decreases the passage of sun rays and directly affects the photosynthetic organisms and the ecosystem. Fungi have potential in the treatment of wastewater containing dyes with complex organic structures due to enzymes that they produce. This study evaluated the use of Phanerochaete chrisosporium in the treatment of synthetic effluent from textile industry containing indigo carmine (20 mg/L). The fungus was immobilized in a semibatch reactor. Glucose was the cosubstrate employed in the experiment and it was used in the system at 1g/L at the beginning of the process and 0.5 g /L after 24 hours of reaction. Average dye removal was 84±10% and chemical oxygen demand removal was 79±14%. For nitrogen compounds, the removal efficiencies were 87±11%, 81±11% and 91±9% for ammonia, nitrite and nitrate, respectively. The pH of the medium remained in the acidic range (2.57 to 5.00) throughout the process, with the lowest values recorded in the effluent of each cycle, justified by the release of organic acids from fungi metabolism. There was contamination of the medium by bacteria (710,000 CFU/mL), but the colonies count showed a predominance of fungi (1,365,000 CFU/mL). With the use of the semibatch system after reading of glucose it was observed that the efficiency of dye removal evolved from 72±17% to 84±10%, producing a final effluent with 3.35±1.99 mg/L of indigo, which proves that treatment configuration analyzed is satisfactory for dye removal.
Subject(s)
Phanerochaete , Environmental Restoration and Remediation , Glucose , Indigo CarmineABSTRACT
RESUMO Água residuária têxtil foi tratada com Aspergillus niger AN 400 em reator de bateladas sequenciais, em ciclos de 48 h para avaliar o efeito de fonte adicional de nitrogênio sobre a eficiência do sistema alimentado com efluente diluído (10% v/v) e glicose (3 g.L-1). O afluente recebeu fonte adicional de nitrogênio (etapa I), acarretando em excesso de nitrogênio amoniacal (192 mg.L-1) no meio, resultando em remoção de matéria orgânica de 85%, porém em apenas 55% de remoção de corante. Ao se diminuir a concentração média de amônia para 98 mg.L-1 (etapa II), a remoção de corante (83%) passou a ser superior à de matéria orgânica, de 69%, mostrando o efeito negativo de concentrações elevadas de amônia sobre o sistema, favorecendo ainda o crescimento de bactérias, o que provavelmente inibiu a produção de enzimas fúngicas e contribuiu para a perda de eficiência na remoção de corante e formação de subprodutos.
ABSTRACT Textile wastewater was treated by Aspergillus niger AN 400 in sequential batch reactor, which was operated in cycles of 48 h in order to evaluate the effect of an additional source of nitrogen on the system's efficiency, which was fed with effluent diluted (10% v/v) and glucose (3 g.L-1). The influent received addition of an external source of nitrogen (phase I), in which there was excess ammonia (192 mg.L-1) in the medium, resulting in organic matter removal of 85%, but in only 55% removal of dye. In the phase II, when the average concentration of ammonia in the medium was lower (98 mg.L-1), removal of dye (83%) became higher than that of organic matter (69%), showing the negative effect of high concentrations of ammonia over the system and favoring the growth of bacteria, which probably inhibit the production of fungal enzymes and contributed to the loss of efficiency in the removal of dye and the formation of byproducts.