Combined Locally Enhanced Electric Field Treatment and Copper for Effective Inactivation of Gram-Positive and Gram-Negative Bacteria in Water.

Locally enhanced electric field treatment (LEEFT) is an emerging technology that employs electric fields to inactivate bacteria in water. Compared to traditional chlorine-based solutions, LEEFT allows for efficient water disinfection while preventing the formation of harmful disinfection byproducts. When combined with copper (Cu), a material recognized for its antimicrobial properties, LEEFT-Cu has demonstrated increased bacteria inactivation efficiency. In this study, LEEFT-Cu is tested for its disinfection performance against 8 different bacteria (4 Gram-negative (G-) and 4 Gram-positive (G+)), each grown in both stable and exponential phases. The primary focus is on the effectiveness of LEEFT-Cu against both gram structures. It is concluded that LEEFT-Cu can achieve >3 log removal for most bacteria species (7/8) using <0.7 mg/L Cu. Additionally, the calculated degree of improvement using LEEFT-Cu in comparison to Cu ions alone indicates >20 times increase in disinfection performance. The degree of improvement also leads to the conclusion that G+ bacteria are up to 3 times more vulnerable to the impacts of EFT (i.e., increased membrane permeability) than G-. Future work should focus on testing the current bench-scale prototype with more complex water matrices to further advance LEEFT-Cu for practical applications in water disinfection.