Steel plant effluents represent considerable environmental constraints due to their high concentrations of contaminants such as heavy metals and organic compounds. This study aimed to evaluate the potential of indigenous bacteria as a bioremediation agent for steel plant effluent. Two isolated indigenous bacterial strains B1 and B3 were identified as Shewanella sp. strain DADJ and Bacillus licheniformis and those were exposed to bioremediation investigations for 15 days. The untreated effluent and the effluent treated with strains Shewanella sp. strain DADJ and Bacillus licheniformis underwent a physicochemical examination to assess changes in parameters like pH, Total Dissolved Solids (TDS), Chemical Oxygen Demand (COD) and Biochemical Oxygen Demand (BOD). Furthermore, the iron content of the untreated effluent was drastically reduced to 18.12±3.15 and 23.08±0.61 μg/mL in the Shewanella sp. strain DADJ and Bacillus licheniformis treated effluents respectively, which proved the potency of the bacterial isolates in reducing iron, a prevalent contaminant in the effluent of steel plants. Heavy metals such as cadmium, arsenic, chromium, lead and mercury were examined in effluents before and after treatment with strains Shewanella sp. strain DADJ and Bacillus licheniformis using ICP-OES spectroscopy. The efficacy of the bioremediation was also assessed by identifying any organic compounds in the effluent both before and after treatment using Gas Chromatography-Mass Spectrometry (GC-MS) analysis. The GCMS study revealed that the 1,2-Benzenedicarboxylic acid, mono(2-ethylhexyl) ester and Silane, dimethyl(2-naphthoxy) heptyloxy only existed in the effluent sample treated with Shewanella sp. strain DADJ and Bacillus licheniformis, which suggested the disappearance of existed chemical compounds into novel compounds. Therefore, this finding demonstrated the efficacy of the indigenous strain Shewanella sp. strain DADJ and Bacillus licheniformis for treating the steel plant effluent.
