Effectiveness Evaluation for Bacteria and Fungi Disinfections of Developed Ozone Machine

Authors

  • Pradya Prempraneerach Thammasat University (Rangsit Campus)
  • Worada Samosornsuk Thammasat University (Rangsit Campus)
  • Sorawit Likitprukpaisan Thammasat University (Rangsit Campus)
  • Itthikorn Prakaisak Thammasat University (Rangsit Campus)

DOI:

https://doi.org/10.4186/ej.2022.26.10.27

Keywords:

ozonation, total ozone dose, ozone decomposition, fungi and bacteria disinfection, cultural test

Abstract

A low-cost ozone machine was developed to generate gaseous ozone for decontaminating the non-ventilated and unoccupied room within a 50-minute ozonation duration. This ozone machine, equipped with a centrifugal blower, could assist in thoroughly dispersing ozone gas throughout an enclosed area, as a result this ozone machine could raise the ozone concentration up to 2.4 ppm inside a 50 square-meter classroom after the ozonation period. Performances of this ozone machine were experimentally evaluated inside both non-ventilated and ventilated classrooms. First, an average total ozone dose of 58 ppm-min, which was close to an upper limit for the >90% viral disinfection, demonstrated the machine effectiveness in the viral inactivation. Second, a waiting period for ozone decomposition and removal using a ceiling ventilated fan could be predicted from an exponential decay rate of ozone concentration to be about 1.5 hour before the decontaminated room could be re-entered safely. Third, the disinfection of bacteria and fungi, which are tougher than most viruses, were validated by the cultural tests using standard plate count agars after the 50-minute ozone exposure. Results of the colony count and microorganism identification using the MALDI-TOF MS and the fungi slide culture technique revealed that 11 species of bacteria and 5 species of fungi could be inactivated by ozone gas after the specified ozonation period.

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Author Biographies

Pradya Prempraneerach

Department of Mechanical Engineering, Faculty of Engineering, Thammasat University (Rangsit Campus), Rangsit, Pathumthani, Thailand

Worada Samosornsuk

Department of Medical Technology, Faculty of Allied Health Sciences, Thammasat University (Rangsit Campus), Rangsit, Pathumthani, Thailand

Sorawit Likitprukpaisan

Department of Mechanical Engineering, Faculty of Engineering, Thammasat University (Rangsit Campus), Rangsit, Pathumthani, Thailand

Itthikorn Prakaisak

Department of Mechanical Engineering, Faculty of Engineering, Thammasat University (Rangsit Campus), Rangsit, Pathumthani, Thailand

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Published In
Vol 26 No 10, Oct 31, 2022
How to Cite
[1]
P. Prempraneerach, W. Samosornsuk, S. Likitprukpaisan, and I. Prakaisak, “Effectiveness Evaluation for Bacteria and Fungi Disinfections of Developed Ozone Machine”, Eng. J., vol. 26, no. 10, pp. 27-38, Oct. 2022.

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