This paper describes the removal of Cr(VI) using the combination of bacterial reduction of Cr(VI) to Cr(III) by wood husk–packed column containing the Cr(VI)-reducing biofilm followed by Cr(III) removal using the coagulation-flocculation technique. The chromium removal process was carried out at the laboratory-scale for 90 days using different batches of Cr(VI) ranging from 35 to 231 mg L⁻¹. Analysis of variance (ANOVA) showed a high coefficient of determination (R²) value of 0.9941, thus ensuring a satisfactory adjustment of the second-order regression model with the experimental data. The experimental observations were in reasonable agreement with the modeled values. The biofilm was able to completely reduce 100 mg L⁻¹ Cr(VI) in 6 h while a longer contact time (18 h) was needed for higher Cr(VI) concentrations. In this study, ORP (oxidation-reduction potential) was used as the control parameter during the Cr(VI) reduction process. The coagulation/flocculation process using the combination of alum and polyacrylamide results in complete removal of color, 85% Cr(III), and 97% turbidity. The field emission scanning electron microscope (FESEM) analysis of the biofilm revealed the embedding of bacterial cells in extracellular polymeric substances (EPS). This study successfully demonstrated the potential application of a bacterial biofilm and chemical systems to remove chromium contamination from water systems.

本文介绍了结合细菌去除Cr（VI）到Cr（III）的去除方法，该方法是通过装有减少Cr（VI）的生物膜的木壳填充柱，然后通过使用Cr（VI）去除Cr（III）。混凝絮凝技术。使用35至231 mg L ^-1的不同批次的Cr（VI）在实验室规模进行了90天的铬去除工艺。方差分析（ANOVA）显示出0.9941的高确定系数（R ²）值，从而确保用实验数据对二阶回归模型进行满意的调整。实验观察与模型值合理吻合。生物膜能够完全减少100 mg L ^-1Cr（VI）在6小时内，而较高的Cr（VI）浓度则需要更长的接触时间（18小时）。在这项研究中，ORP（氧化还原电位）被用作Cr（VI）还原过程中的控制参数。使用明矾和聚丙烯酰胺的组合进行的凝结/絮凝过程可完全去除颜色，85％的Cr（III）和97％的浊度。生物膜的场发射扫描电子显微镜（FESEM）分析显示细菌细胞嵌入细胞外聚合物（EPS）中。这项研究成功地证明了细菌生物膜和化学系统在去除水系统中铬污染方面的潜在应用。