Continuous Disinfection of Fusarium oxysporum in Nutrient Solution by Pulsed Electric Field

The disinfection of recirculating nutrient solution is essential to avoid disasters due to the dispersal of pathogens in a closed soilless culture system. In this work, a disinfection technique using pulsed electric field (PEF) has been investigated. A system was designed to implement continuous disinfection treatment of nutrient solution. The system mainly includes two parts: 1) a pulsed power generator that produces repetitive pulses with amplitude of between 0 kV and 5 kV with a pulse duration of
$10\ \mu\mathrm{s}$
and a pulse repetition frequency of 50 Hz and 2) a parallel-plate treatment chamber used to realize continuous processing. In order to verify the efficacy of PEF treatment Fusarium oxysporum, being amongst the most destructive root-borne diseases, was selected as the object of study and therefore the nutrient solution was inoculated with this pathogen. The results indicate that PEF treatment deactivated most of the Fusarium oxysporum in the nutrient solution, achieving a maximum disinfection efficiency of 99%. At the same time, no obvious changes of the inorganic compositions in the PEF-treated nutrient solution were observed. The overall system is simple and convenient to be operated, worked stably and was capable of achieving a continuous treatment. This work therefore clearly demonstrates the feasibility of continuous PEF disinfection treatment in real soilless culture systems, opening the door for implementation in various agricultural applications.