The supply of clean drinking water is considered as a major public health milestone for our generation. Waterborne diseases are still the third leading cause of death. The recent outbreaks of Legionella in the US and Hong Kong demonstrate the long viability of bacteria in contaminated water distribution system. Existing disinfection technologies rely on the use of chemicals to safeguard water production, which raises many questions other than disinfection effectiveness solely. The Pulsed-Electric Field (PEF) technology is widely used in fluid food sterilisation processes. Microbial cell walls will be elongated and suppressed under a pulse electric field. This causes irreversible damage to the microbial cell wall. Inner structures such as cytoplasm of the microbial cell wall will...[ Read more ]

The supply of clean drinking water is considered as a major public health milestone for our generation. Waterborne diseases are still the third leading cause of death. The recent outbreaks of Legionella in the US and Hong Kong demonstrate the long viability of bacteria in contaminated water distribution system. Existing disinfection technologies rely on the use of chemicals to safeguard water production, which raises many questions other than disinfection effectiveness solely. The Pulsed-Electric Field (PEF) technology is widely used in fluid food sterilisation processes. Microbial cell walls will be elongated and suppressed under a pulse electric field. This causes irreversible damage to the microbial cell wall. Inner structures such as cytoplasm of the microbial cell wall will diffuse out of the cell through enlarged pores. Thus, the microbial cell is no longer able to survive. PEF disinfection can effectively inactivate the bacteria in food products without altering the taste, colour, and nutrients. However, current PEF devices are bulky and require high input voltage pulse, which is not suitable for household usage. In this study, the PEF electrodes were redesigned for using under low input voltage. Two electrodes, multi-layered electrode and spiral-wound electrode were successfully designed, fabricated, and tested. The electrodes were able to achieve 99% bacteria reduction. Parametric effects to PEF disinfection performance were also studied. The parameters include: E-field direction, pulse width, and applied voltage. At higher applied voltage and longer pulse width, the PEF disinfection performance is better.