Inactivation of Vibrio spp. in water using micro-nano-bubbles, ultrasound, and hydrogen peroxide

Abstract

Recently, the development of water disinfection technology that does not generate chemical residues or by-products has attracted much research interest. This study presents the results of Vibrio spp. disinfection using a combination treatment of micro-nano-bubbles (MNBs), ultrasound (US), and hydrogen peroxide (H₂O₂). The bactericidal performance of the combined treatment was conducted at various H₂O₂ dosages and airflow rates. The results show that with H₂O₂ added at ~30% of a normal dose (required for sufficient disinfection by H₂O₂ alone), disinfection efficiency of the combined MNBs/US/H₂O₂ treatment was greatly enhanced and was higher than that of individual treatments (US or H₂O₂). Specifically, under treatment conditions (initial bacterial density of 10⁵-10⁶ CFU/mL and salinity of 20‰), the combined treatment of MNBs (1.5 L/min)/US (28 kHz)/H₂O₂ (0.9 mg/L) achieved a synergy value of 3.3 log and completely inactivation (5.4 log reduction) of Vibrio spp. within 60 min. Meanwhile, disinfection with H₂O₂ (0.9 mg/L) led to only 1.7 log reduction, and disinfection with US (28 kHz, 100 W) reduced only 0.5 log within 60 min. These results promise an alternative method for brackish water disinfection applications such as aquaculture water treatment.