Inactivation of Escherichia coli and somatic coliphage ΦX174 by oxidation of electrochemically produced Fe²⁺

Inactivation of Escherichia coli and somatic coliphage ΦX174 by oxidation of electrochemically produced Fe²⁺

Bicudo, Bruno (TU Delft Sanitary Engineering)
Medema, G.J. (TU Delft Sanitary Engineering; KWR Water Research Institute; Michigan State University)
van Halem, D. (TU Delft Sanitary Engineering)

2022

Electrochemical ferrous iron (Fe²⁺) wastewater treatment is gaining momentum for treating municipal wastewater due to its decreasing costs, environmental friendliness and capacity for removal of a wide range of contaminants. Disinfection by iron electrocoagulation (Fe-EC) has been occasionally reported in full scale industrial applications, yet controversy remains regarding its underlying elimination mechanisms and kinetics. In this study, it was demonstrated that substantial inactivation can be achieved for Escherichia coli WR1 (5 log₁₀) and somatic coliphage ΦX174 (2–3 log₁₀). Electrochemically produced Fe²⁺ yielded similar inactivation as chemical Fe²⁺. Reactive oxygen species (ROS)-quenching experiments with TEMPOL confirmed that E. coli inactivation was related to the production of Fenton-like intermediates during Fe²⁺ oxidation. The observed E. coli disinfection kinetics could be mathematically related to Fe-EC current intensity using a Chick-Watson-like expression, in which the amperage is surrogate for the disinfectant's concentration. We hereby show that it is possible to mathematically predict disinfection based on applied Fe dosage and dosage speed. Phage ΦX174 inactivation could not be described in a similar way because at higher Fe dosages (>20 mg/l), little additional inactivation was observed. Also, ROS-quencher TEMPOL did not completely inhibit phage ΦX174 removal, suggesting that additional pathways are relevant for its elimination.

Disinfection
Electrocoagulation
Reactive oxygen species
TEMPOL
Water reclamation

http://resolver.tudelft.nl/uuid:8437ee3a-7f3d-4342-a968-40a428f3d9eb

https://doi.org/10.1016/j.jwpe.2022.102683

2214-7144

Journal of Water Process Engineering, 47

Institutional Repository

journal article

© 2022 Bruno Bicudo, G.J. Medema, D. van Halem