Removal of Escherichia coli and Enterococcus faecalis from synthetic wastewater using thermally treated palygorskite as a bacterial adsorbent in fixed bed reactors

Abstract

BACKGROUND

In pursuit of innovative wastewater treatment solutions, this study investigates the use of thermally treated palygorskite (TP) as an adsorbent to remove Escherichia coli and Enterococcus faecalis from synthetic wastewater. The goal is to explore a natural alternative to chlorine-based disinfectants by utilizing TP's antimicrobial properties. Columns were packed with two granulometries (G1: 0.25–0.6 mm; G2: 1.40–2.36 mm) of TP and arranged in three different configurations (CA1, CA2 and CA3) to assess their bacterial removal efficiency, kinetic behavior and potential for reuse after dry heat sterilization.

RESULTS

The CA3 column configuration, with its multilayer arrangement of TP, achieved the highest bacterial removal efficiency, reaching 99.1% for E. coli and 98.1% for E. faecalis. Kinetic experiments revealed that most bacterial adsorption occurred within the first 3 min, with E. coli requiring up to 10 min to reach maximum removal. TP's antibacterial effectiveness remained above 90% after two reuses. Additionally, dry heat sterilization allowed for repeated use of TP, showing stable removal efficiencies for E. faecalis and a slight decline for E. coli with each successive reuse.

CONCLUSIONS

TP demonstrates significant potential as an adsorbent for wastewater disinfection, particularly in the CA3 multilayer configuration. Its rapid adsorption kinetics and resilience to heat sterilization underscore its reusability, making it a viable natural alternative to chemical disinfectants. Further research should focus on scaling this method to real wastewater treatment applications to validate its functionality in real-world conditions. © 2024 Society of Chemical Industry (SCI).