Investigation of Physicochemical Characteristics, Elemental Composition and GCMS Studies on Steel Plant Effluent Treated with Indigenous Bacteria

Aim/ Background: Steel plant effluents pose significant environmental challenges due to the high concentrations of contaminants such as heavy metals and organic compounds. This study aimed to evaluate the potential of indigenous bacteria, specifically Shewanella sp. strain DADJ and Bacillus licheniformis, as bioremediation agents for the treatment of steel plant effluent. Materials and Methods: Two indigenous bacterial strains, Shewanella sp. strain DADJ and Bacillus licheniformis, were isolated and exposed to steel plant effluent for a 15-day period. The physicochemical properties of untreated and treated effluent, including pH, Total Dissolved Solids (TDS), Chemical Oxygen Demand (COD), and Biochemical Oxygen Demand (BOD), were analyzed. Additionally, the reduction of iron and other heavy metals (cadmium, arsenic, chromium, lead, and mercury) in the effluent was assessed using ICP-OES spectroscopy. Organic compounds in the effluent were analyzed both before and after treatment using Gas Chromatography-Mass Spectrometry (GC-MS). Results: The results showed that the untreated effluent had high concentrations of iron and heavy metals. After treatment with the bacterial strains, the iron content was drastically reduced to 18.12 ± 3.15 μg/mL and 23.08 ± 0.61 μg/mL in the effluents treated with Shewanella sp. strain DADJ and Bacillus licheniformis, respectively. The ICP-OES analysis revealed significant reductions in cadmium, arsenic, chromium, lead, and mercury. GC-MS analysis indicated that the organic compounds, including 1,2-Benzenedicarboxylic acid, mono(2-ethylhexyl) ester, and Silane, dimethyl(2-naphthoxy) heptyloxy, were present only in the treated effluent, suggesting the transformation of existing chemical compounds into novel ones. Conclusion: The Indigenous bacterial strains Shewanella sp. strain DADJ and Bacillus licheniformis demonstrated effective bioremediation potential for treating steel plant effluent by significantly reducing iron, heavy metals, and organic contaminants.