Influência do excesso de nitrogênio amoniacal no tratamento de efluente têxtil em reator de bateladas sequenciais com Aspergillus niger AN 400 / Influence of excess nitrogen in the treatment of the textile effluent in sequential batch reactors with Aspergillus nigerAN 400

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.

Azo dye degradation by Phanerochaete chrysosporium in the medium enriched with nitrogen in the presence of primary co-substrate

This work sought to evaluate the ability of fungi Phanerochaete chryosporium to degrade congo red azo dye in batch reactor, evaluate the influence of glucose and wheat bran as co-substrates on the removal of the dye in the medium and investigate the influence of ammonium chloride, ammonium nitrate and ammonium sulfate as the inorganic nitrogen source for the process. Wheat bran was not effective satisfactorily for the removal of dye and organic matter had no desired effect for the removal of color and organic matter and showed the lowest values of k2, 0.008 M-1.d-1and 0.0004 M-1.d-1, respectively. Glucose presented the best response with the highest final percentage of dye removal (97%) and rate of dye removal (0.017 M-1.d-1), without adding an external source of nitrogen.