Killing of total heterotrophic bacteria using the gas diffusion electrode system

摘要

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.