In this present study, bacteria were isolated from wastewater and polluted soil collected from two cottage textile factories in Ibadan. These bacteria isolates were used for the biotreatment of textile mill effluent. The physicochemical parameters of the textile mill effluent before treatment were carried out and percentage decolourisation of the effluent was analysed using ultraviolet-visible spectroscopy (UV-vis technique). The degradation products of the textile mill effluent characterised by Fourier transform infrared spectroscopy (FTIR). The pH values of the effluent were within the permissible limit of Federal Environmental Protection Agency (FEPA) and National Environmental Standards and Regulations Enforcement Agency (NESREA), while temperature and electric conductivity of the effluents were below the permissible limit of FEPA and NESREA. The BOD, COD, TSS, TDS and chloride of the textile mill effluent from the two cottage textile factories were above the permissible limits of FEPA and NESREA. Twelve bacteria isolates were screened, effective in decolourising commercial dyes and used to decolourise the textile mill effluent. The bacteria isolates were characterised and identified as Bacillus sp., Micrococcus sp., Erwinia sp., Acinetobacter sp. and Nocardia sp. The decolourisation of textile effluent was observed through the changes of spectra of UV-visible spectrophotometer. The following bacteria revealed different percentage proportion of decolouration profile:- Bacillus sp., had the highest percentage decolourisation of 57.7%, whereas Micrococcus sp. and Acinetobacter sp. had percentage decolourisation of 32.8 and 26.3%, respectively. The degradation profile of textile effluent was revealed through FTIR spectral analysis. The changes in the position of major peaks revealed from the textile effluent through FTIR spectral analysis, appearances of new peaks and the disappearances of existing peaks signify the degradation of the wastewater. Thus, some native microorganisms from the textile effluent could be enhanced to effectively degrade effluent from such environments.
Keywords: Biotreatment; Decolourisation; Degradation; Dye; FTIR spectral analysis; Functional groups; Textile effluent.