Ozone in the Clinical Environment

Introduction

Beyond treating individual patients, ozone has powerful applications in maintaining the clinical environment itself. As a potent oxidising agent, ozone can sterilise air, surfaces, and water — making it a valuable tool for infection control in veterinary practices.

This guide covers two main applications: using ozone for theatre and clinic decontamination, and treating hospital wastewater to reduce environmental contamination and antimicrobial resistance.

With increasing concern about antimicrobial resistance (AMR), ozone offers a way to reduce pathogen loads without contributing to resistance — both in direct patient care and in the wider environment.

Theatre & Clinic Sterilisation

Why Use Ozone for Decontamination?

Traditional cleaning methods have limitations. Chemical disinfectants may leave residues, some pathogens develop resistance to biocides, and manual cleaning cannot reach every surface. Ozone addresses these challenges:

Reaches everywhere: As a gas, ozone penetrates into crevices, behind equipment, inside ventilation systems, and other areas that manual cleaning cannot access.

Kills resistant organisms: Ozone destroys bacteria, viruses, fungi, and spores — including antibiotic-resistant strains like MRSA and biofilm-forming organisms.

Significantly reduced resistance risk: Unlike antibiotics and some chemical disinfectants, pathogens are far less likely to develop resistance to ozone compared to antibiotics due to its mechanism of action.

No chemical residues: Ozone breaks down to oxygen, leaving no toxic residues on surfaces or in the air.

Neutralises odours: Ozone breaks down volatile organic compounds that cause clinical odours.

How It Works

Ozone (O₃) destroys microorganisms by oxidising their cell walls and viral capsids. This oxidative damage is rapid and lethal to pathogens, but ozone quickly reverts to ordinary oxygen (O₂), making it safe once the treatment cycle is complete.

Room ozonation typically involves:

• Sealing the room (closing doors, covering vents if needed)
• Running an ozone generator to achieve target concentration
• Maintaining concentration for a set contact time
• Ventilating the room before re-entry

Modern systems can be automated and timed to run overnight or between procedures.

Applications in Veterinary Practice

• Surgical theatres — between procedures or end-of-day decontamination
• Consulting rooms — particularly after infectious cases
• Isolation units — essential for disease control
• Kennels and catteries — reduce disease transmission
• Dental suites — where aerosols create contamination
• Ambulances and mobile units — field decontamination

What does the research say?

Rangel et al. (2022) Potent Activity of a High Concentration of Chemical Ozone against Antibiotic-Resistant Bacteria (Molecules, 27(13), 3998. https://doi.org/10.3390/molecules27133998)

Piletić et al. (2022) Disinfecting Action of Gaseous Ozone on OXA-48-Producing Klebsiella pneumoniae Biofilm In Vitro (International Journal of Environmental Research and Public Health, 19(10), 6177. https://doi.org/10.3390/ijerph19106177)

Epelle et al. (2022) Bacterial and fungal disinfection via ozonation in air (Journal of Microbiological Methods, 194, 106431. https://doi.org/10.1016/j.mimet.2022.106431)

Knobling et al. (2021) Evaluation of the Effectiveness of Two Automated Room Decontamination Devices Under Real-Life Conditions (Frontiers in Public Health, 9, 618263. https://doi.org/10.3389/fpubh.2021.618263)

Steinmann et al. (2021) Virucidal efficacy of an ozone-generating system for automated room disinfection (Journal of Hospital Infection, 119, 84-117. https://doi.org/10.1016/j.jhin.2021.07.014)

Agostini et al. (2021) In Vitro Comparison of Antibacterial Effect of Ozonated Water and Ozonated Gas(Ozone: Science & Engineering, 43(4). https://doi.org/10.1080/01919512.2020.1811636)

Practical Implementation

Equipment Considerations

When selecting ozonation equipment for your practice:

• Output capacity — must be sufficient for the room volume
• Concentration monitoring — real-time measurement ensures effective treatment
• Timer controls — allows unattended operation
• Safety features — automatic shutoff, door sensors
• Portability vs fixed — consider your practice layout

Safety Protocols

Ozone is a respiratory irritant at high concentrations. Essential safety measures:

• Never enter a room during active ozonation
• Use door signage and lockout procedures
• Allow adequate ventilation time before re-entry (typically 30-60 minutes)
• Install ozone monitors if using fixed systems
• Train all staff on protocols

When used correctly, ozone sterilisation is safe and leaves no residues. The room is ready for normal use once ozone levels return to background.

Integration with Cleaning Protocols

Ozone complements rather than replaces standard cleaning:

• Physical cleaning first — remove organic matter and debris
• Standard disinfection — for immediate pathogen reduction
• Ozonation — for deep decontamination, reaching areas manual cleaning misses

Many practices use ozonation as an end-of-day or weekly deep clean, with standard protocols between.

Hospital Wastewater Treatment

The Problem

Veterinary hospital wastewater contains a cocktail of concerning substances:

• Bacteria, including antibiotic-resistant strains
• Pharmaceutical residues — antibiotics, anaesthetics, NSAIDs
• Disinfectant chemicals
• Biological material

When this wastewater enters the sewage system and eventually the environment, it contributes to antimicrobial resistance in environmental bacteria and may contaminate water supplies.

Antibiotic residues in wastewater create selective pressure for resistance development in environmental bacteria — a significant driver of the global AMR crisis.

How Ozone Helps

Ozone treatment of wastewater addresses multiple concerns:

• Kills pathogens: Bacteria, viruses, and other microorganisms are destroyed by oxidation, including antibiotic-resistant strains.
• Degrades pharmaceuticals: Many drug residues are broken down into less harmful compounds.
• Destroys resistance genes: Ozone can damage the DNA carrying antibiotic resistance genes, potentially reducing horizontal gene transfer, though complete elimination of resistance genes may require optimised dosing and contact time.
• Improves water quality: Reduces biological and chemical oxygen demand (BOD/COD).
• No chemical addition: Unlike chlorination, ozone treatment doesn’t add persistent chemicals.

What does the research say?

Azuma et al. (2022) Inactivation of Antibiotic-Resistant Bacteria in Wastewater by Ozone-Based Advanced Water Treatment Processes (Antibiotics, 11(2), 210. https://doi.org/10.3390/antibiotics11020210)

Baghal Asghari et al. (2021) Performance evaluation of ozonation for removal of antibiotic-resistant Escherichia coli and Pseudomonas aeruginosa and genes from hospital wastewater (Scientific Reports, 11. https://doi.org/10.1038/s41598-021-04254-z)

Hansen et al. (2016) Ozonation for source treatment of pharmaceuticals in hospital wastewater – Ozone lifetime and required ozone dose (Chemical Engineering Journal, 290, 507-514. https://doi.org/10.1016/j.cej.2016.01.027)

De Witte et al. (2010) Ciprofloxacin ozonation in hospital wastewater treatment plant effluent: effect of pH and H2O2(Journal of Hazardous Materials, 169(1-3), 1154-1158. https://doi.org/10.1016/j.jhazmat.2009.03.143)

Aleksić et al. (2021) Ozonation of Amoxicillin and Ciprofloxacin in Model Hospital Wastewater to Increase Biotreatability (Antibiotics, 10(11), 1407. https://doi.org/10.3390/antibiotics10111407)

Svebrant et al. (2021) On-Site Pilot Testing of Hospital Wastewater Ozonation to Reduce Pharmaceutical Residues and Antibiotic-Resistant Bacteria (Antibiotics, 10(6), 684. https://doi.org/10.3390/antibiotics10060684)

Implementation Options

Wastewater ozonation can be implemented at various scales:

Point-of-Use Treatment

Treating specific waste streams before they enter the main drainage:

• Theatre wastewater
• Laboratory effluent
• Isolation unit drainage

This targeted approach treats the most contaminated streams at source.

End-of-Pipe Treatment

Treating all practice wastewater before discharge:

• Requires a holding tank and treatment system
• Treats everything — comprehensive but higher investment
• May be required for larger practices or those in sensitive locations

Considerations

• Regulatory requirements — check local discharge consents
• Volume and flow rates — system sizing
• Contact time — adequate treatment duration
• Monitoring — verification of treatment efficacy
• Maintenance — ozone generators require periodic servicing

The Business Case

Investing in ozone technology for your practice offers several benefits:

Infection Control

• Reduced hospital-acquired infection rates
• Better outcomes for surgical patients
• Protection for immunocompromised patients
• Safer working environment for staff

Operational Efficiency

• Faster room turnaround (no residue drying time)
• Reduced chemical disinfectant costs
• Less manual cleaning time for deep decontamination
• Automated overnight operation

Reputation & Compliance

• Demonstrates commitment to infection control
• Meets increasing client expectations
• Supports sustainability credentials (no chemical residues)
• May become regulatory requirement in future

Environmental Responsibility

• Reduces practice contribution to AMR
• Protects the local water environment
• Aligns with One Health principles
• Supports the veterinary profession’s environmental commitments

Getting Started

If you’re considering ozone technology for your practice:

• Assess your needs — which applications are most relevant?
• Calculate room volumes — for appropriate equipment sizing
• Review existing protocols — identify where ozone fits
• Consult suppliers — discuss options and get demonstrations
• Train staff — safety and operational procedures
• Document protocols — standard operating procedures
• Monitor outcomes — track infection rates, client feedback

Ozone Animal Health can advise on equipment selection and implementation for veterinary practices. Contact us to discuss your specific requirements.