Textile effluent characterization and evaluation of capacity color removal using the fungus Lasiodiplodia theobromae MMPI
ABSTRACT The industrial processes of textile production are characterized by the use of large volumes of water during the washing steps and fabric dyeing, resulting in effluent with enormous diversity and chemical complexity. The presence of dissolved dyes is quite noticeable and problematic, considering their recalcitrance and slow degradation kinetic. In this work, the Lasiodiplodia theobromae MMPI fungus was evaluated for their ability to removing color from effluent. The assays were performed in a bench-scale bioreactor (5 L) with an incubation time of 192 hours. The decoloring efficiency ranged from 19.52% on 24h to 91,26% on 168 h and the mycelial biomass production ranged from 1.23 g.L-1 (24 h) to 7.60 g.L-1 (168 h). Production of exopolysaccharide (EPS) also was observed, with amounts ranged from 2.84 g.L-1 (24 h) to 4.28 g.L-1 (48 h). The characterization of the effluent showed some values of control parameters outside the discharge standards required by Brazilian law, with high Chemical Oxygen Demand (COD) (659 mg.L-1) and Biochemical Oxygen Demand (BOD5) (328 mg.L-1). The toxicity analysis using the microcrustacean Artemia salina, showed that the raw effluent concentration that caused 50% mortality of organisms (LC50) was approximately 14.72% (v/v) and at the end of treatment was 4.98% (v/v). Although the fungus was not efficient in biological detoxification of the effluent, it showed promising results for its color removal capacity, demonstrating potential for use in auxiliary treatment processes of textile effluents for the color removal.