Bacterial diversity, organic pollutants and their metabolites in two aeration lagoons of common effluent treatment plant (CETP) during the degradation and detoxification of tannery wastewater

Abstract

In this study, PCR-RFLP and GC-MS approaches were used to characterize the bacterial diversity, organic pollutants and metabolites during the tannery wastewater treatment process at common effluent treatment plant (CETP). Results revealed that the bacterial communities growing in aeration lagoon-I were dominated with Escherichia sp., Stenotrophomonas sp., Bacillus sp. and Cronobacter sp. while that of aeration lagoon-II prevailed with Stenotrophomonas sp., and Burkholderiales bacterium, respectively. The HPLC and GC-MS analysis revealed that most of the organic pollutants detected in untreated tannery wastewater samples were diminished from bacterial treated tannery wastewater samples. Only two pollutants i.e. L-(+)-lactic acid and acetic acid could not be degraded by bacteria whereas benzene and 2-hydroxy-3-methyl-butanoic acid was produced as new metabolites during the bacterial treatment of tannery wastewater in aeration lagoon II of CETP. Further, it was observed that after bacterial treatment, the toxicity of tannery effluent was reduced significantly allowing 90% seed germination.