A Study on Inactivation of Pathogenic Bacteria for Nutrient Solution Recycling Using Advanced Oxidation Processes

Abstract

This study was conducted to test the applicability of hydroxy radical reactor system, which applied advanced oxidation processes, to sterilize pathogenic bacteria for nutrient solution recycling in closed hydroponics. Removal efficiency was tested on 25 L of nutrient solution maxed with 10 mL culture solution of bacteria, E. coli, and R. solanacearum in a pilot tank. The testing conditions included various levels of hydroxy radicals resulting from air flow rates of 40, 80, and 120 L min-1, and 12 hours processing time. The removal of bacteria, E. coli, and R. solanacearum by hydroxy radical in nutrient solution was significantly increased with an increase in the flow rate of the air from 40 L min-1 to 120 L min-1. The optimum removal efficiency was achieved at an air flow rate of 120 L min-1 for 2 hours treatment. There were no significant differences in removal efficiency among bacteria, E. coli, and R. solanacearum for tested level and time of hydroxy radical. These results verified the efficiency of hydroxy radical in removing the pathogenic bacteria and the applicability of hydroxy radical reactor system in the field. Removal efficiency of pathogenic bacteria by hydroxy radical resulting from air flow level of 40, 80, and 120 L min-1. Removal efficiency of bacteria, E. coli, and R. solanacearum by hydroxy radical from air flow level of 120 L min-1.