Killing of total heterotrophic bacteria using the gas diffusion electrode system

Abstract

This study focused on the disinfection of dual electrodes with a gas diffusion cathode using total heterotrophic bacteria as indicator microorganisms. Batch tests were performed to study the effects of platinum load W Pt and the pore-forming agent content W NH4HCO3 in gas diffusion electrodes on the germicidal efficacy η and H 2O 2 yield. The results showed that the disinfection improved with W Pt, but its efficiency at W Pt of 3‰ was equivalent to W Pt of 4‰. The right amount of the pore-forming agent improved disinfection. Continuous tests were performed to study residence times (RTs), pH and oxygen flow rates Q O2 on the germicidal efficacy and H 2O 2 yield. The results indicated that at the steady state total heterotrophic bacteria in the outlet stream were completely inactivated under our experimental conditions. Disinfection improved with increasing RT. This phenomenon was more significant when RT<20 min. A drop in pH value resulted in the rapid rise of germicidal efficacy, while disinfection shortened with an increasing oxygen flow rate Q O2. The operating costs are high. Further research is required to fully understand all parameters and reduce operating costs.