Tannery effluent treatment in an effluent treatment plant enriched by
microbial mixture is insufficient to remove contaminants
Abstract
Tannery effluents (TE) are the major hazardous chemical wastes generated
by the leather or tannery industries during the processing and finishing
of the leather. Across the globe, India has secured second rank in
leather industries, contributing to producing hazardous chemical
wastes/tannery effluents that disturb the ecological balance. The
conventional microbial treatment strategy is one of the options, which
decreases the level of hazardous chemical wastes from tannery effluents.
This study aims to evaluate TE’s chemical composition, organic texture,
and metabolites using GC-MS, ICP-MS and other physiochemical analyses
after the conventional microbial treatment process at a common effluent
treatment plant (CETP). The results showed that most of the pollutant
parameters like COD, BOD, metal ions, sulphate, chromium, and organic
pollutants were significantly reduced in TE after the microbial
treatment. Moreover, results also showed that chlorophenols and
phthalate derivatives could not be biodegraded by the indigenous
microbial population in the aeration pond/tank of CETP.
Dichlorodihydrofluorescein (DCF) assay on cell line showed that
untreated TE extract has the highest reactive oxygen species (ROS)
production than other samples (all p<0.01). The genotoxicity
of TE was reduced significantly in terms of Olive Tail Moment (OTM) and
% tail DNA after the conventional treatment process at CETP by 58.4%
and 36.45% in aerated tanks 1 and 2, respectively. However, TE samples
had higher pollution parameters and toxic effluents even after
conversion through microbial treatment. Therefore, results suggested
that adequate treatment of TE is crucial before its final
disposal/discharge into the environment.