The application of a boron-doped diamond
electrode in electrochemical water disinfection was investigated
with respect to its inactivation potential of three
indicator microorganisms. Drinking water and the effluent
of a wastewater treatment plant spiked with
Escherichia coli
,
Enterococcus faecium
and
Pseudomonas aeruginosa
were electrolysed under different conditions in a batch
reactor. All three bacteria species could be successfully
inactivated in drinking water. The disinfection rate
depended on the applied charge, with far more efficiency at
high current densities (208 and 333 mA/cm
2) under high
ozone concentrations measured in contrast to low current
densities (42 mA/cm
2) where bacterial inactivation was
rather driven by hydroxyl radicals. When oxidising a target
pharmaceutical compound in the wastewater treatment
plant effluent, the water matrix exhibited an ozone scavenging
effect. The resulting decrease in the efficiency
could not be detected for the disinfection experiments in
the complex water matrix compared to drinking water,
which indicates a different disinfection mechanism, probably
due to reactive chlorine species.
