Lab-scale experiments and model analyses for bacterial removal in flow-through columns containing dolomite

摘要

The aim of this study was to investigate the removal of bacteria (Bacillus subtilis ATCC 6633) from aqueous solutions using dolomite as a filter medium. Column experiments were performed in step injection mode under various conditions of influent bacterial concentration (0.5-2.0 g/L), flow rate (0.5-1.5 mL/min), and column length (10-30 cm). The highest percentage bacterial removal (Re) of 75.2 ±1.6% was obtained under the following conditions: influent bacterial concentration = 1.0 g/L; flow rate = 0.5 mL/min; column length = 20 cm. The highest column capacity for bacterial removal (q_0) of 2.126 ± 0.067 mg/g was achieved using an influent bacterial concentration of 2.0 g/L, flow rate of 1.0 mL/min, and column length of 20 cm. Increasing the bacterial concentration and flow rate had a negative effect on Re, whereas the q_0 values were positively affected. Increasing the column length produced a positive effect on Re, whereas q_0 declined. Simulation of the breakthrough curves (BTCs) using the Adams-Bohart, Thomas, Yoon-Nelson, and dose-response kinetic models demonstrated that the Adams-Bohart model adequately reproduced the initial part of the BTC, whereas the Thomas and Yoon-Nelson models were suitable for describing the transient stage of the BTC between the breakthrough point and saturation point. Compared to the aforementioned models, the dose-response model produced an adequate simulation of the entire BTC. This study demonstrates the adequate performance of dolomite as a filter material for the removal of bacteria from aqueous solutions.