(254am) Performance of a Micro-Mini Pulsed Electric Field (PEF) Device for Drinking Water Disinfection

Authors: 
Wongsrisujarit, N., The Hong Kong University of Science and Technology
Hung, P. S., The Hong Kong University of Science and Technology
Kwan, S. M., Hong Kong University of Science and Technology
Lee, O. W., The Hong Kong University of Science and Technology
Kwan, J. K. C., The Hong Kong University of Science and Technology
Yeung, K. L., The Hong Kong University of Science and Technology
Clean drinking water supply is considered a major public health milestone of our generation. However, waterborne diseases are still the third leading cause of death. The Word Health Organization (WHO) reported that diarrhoeal diseases from unsafe water kills 1.5 million children each year and causes two billion cases of illness worldwide (WHO Diarrhoeal disease, fact sheet No.330). Recently, there was an outbreak of waterborne diseases in a hospital in US in 2012. Centers for Disease Control and Prevention (CDC) claimed the Legionella found in the hospital in 1982 is almost the same to the Legionella in this outbreak indicating the long viability of bacteria in contaminated water distribution system. Existing disinfection technologies relies on chemicals to safeguard water producing in many cases undesired byproducts and change in water quality in term of odor and taste. This work presents a design for a new micro-mini Pulsed Electric Field (PEF) device that utilizes a low voltage pulse electric field generator with micro-engineered electrodes to disinfect microorganisms found in drinking water. The device is designed to attain 99.9% bacterial reduction. The killing effect is achieved by a low-voltage input to the system to avoid electrolysis and has low energy consumption. The intense electric field perturbs the cell wall resulting in both irreversible and reversible enlargement of intracellular pores. The former results in rapid cell inactivation and death while the latter renders the cell nonviable by an increased ingress of residual chlorine in the tap water.