Overview
Chlorine Dioxide (ClO₂) has been a trusted solution for hospital decontamination and water treatment since the 1940s. Initially discovered in 1814 by Sir Humphry Davy during an experiment where he accidentally produced chlorine dioxide gas by reacting sulphuric acid with potassium chlorite, chlorine dioxide is now recognised as a powerful disinfectant with numerous applications.
Chlorine Dioxide: A Powerful Oxidising Agent
ClO₂ is a potent oxidising agent, known for its virucidal, sporicidal, and fungicidal properties. In its gaseous form, chlorine dioxide appears yellowish-green and is highly soluble in water. Unlike other gases, chlorine dioxide does not escape from water (hydrolysis) but remains dissolved. It gradually breaks down into chlorine and oxygen. Due to its explosive nature in gas form, chlorine dioxide is typically used in aqueous solutions for safety reasons.
Chlorine Dioxide in Water Treatment
The importance of controlling microbial growth in water systems has been well understood for decades. Introducing disinfectants into water systems is essential to effective water management, and chlorine dioxide plays a crucial role in this process.
Chlorine Dioxide for Drinking Water Treatment
Failing to adequately disinfect drinking water can lead to waterborne infections caused by harmful bacteria, viruses, protozoa, and parasitic worms such as tapeworms and roundworms. The water treatment process includes several stages, such as flocculation (increasing particle size) and sand filtration.
To ensure microbial-safe drinking water and reduce the risk of Legionella and Pseudomonas infections, a disinfectant like chlorine dioxide is often added after filtration. Chlorine dioxide is particularly effective in controlling microorganisms, providing low taste impact and excellent biocidal properties at low concentrations. It is also highly effective in removing biofilms, which are commonly found in water systems.
Chlorine Dioxide for Cooling Tower Maintenance
Chlorine dioxide is commonly used to disinfect and clean cooling towers, particularly during planned preventative maintenance or after extended shutdowns. It effectively controls Legionella bacteria and reduces biofilm buildup, which can lead to corrosion damage in internal pipework and pump systems. This results in an extended lifespan for cooling plant infrastructure. Chlorine dioxide is introduced into the cooling system on demand through a specialised control system that mixes acid with sodium chlorite to generate chlorine dioxide.
Chlorine Dioxide for Hospital Decontamination
Since the early 1980s, chlorine dioxide has been employed in healthcare settings to disinfect a wide variety of equipment and surfaces. It is regarded as a powerful, broad-spectrum biocide, with proven efficacy against some of the most resilient microorganisms, including bacterial spores (e.g., Bacillus cereus, Clostridioides difficile) and viruses (e.g., poliovirus, adenovirus, murine norovirus).
Microbiological Efficacy Standards for Disinfectants in the UK
All disinfectants used in healthcare must be tested for microbiological efficacy by UKAS-certified laboratories. The following EN standards should be adhered to when selecting a suitable disinfectant for healthcare environments:
• EN 17126: Sporicidal activity
• EN 14348: Mycobactericidal and tuberculocidal activity
• EN 14476: Virucidal activity
• EN 13624: Fungicidal and yeasticidal activity
• EN 16615: Yeasticidal and bactericidal activity
• EN 13727: Bactericidal activity
For detailed guidance on test types, test microorganisms, and required log reductions, refer to the EN 14885 standard, which provides a comprehensive framework for testing the antimicrobial activity of disinfectants.
You can search for these standards on the BSI website: https://www.bsigroup.com/en-GB/products-and-services/standards/
Applications of Chlorine Dioxide in Healthcare Settings
Birthing Pools
Birthing pools require thorough cleaning and disinfection between each use. Chlorine dioxide is commonly used, both for disinfecting the pool surfaces and for sanitising the drain. A Standard Operating Procedure (SOP) should be displayed near each birthing pool to ensure compliance with hygiene protocols.
Reverse Osmosis Systems
Chlorine dioxide is an effective biocide for controlling microbial growth in Reverse Osmosis (RO) systems. It is particularly beneficial for reducing and removing biofilms, serving as an alternative to thermal disinfection methods. According to HTM 01-06 guidelines, if a biocide is used, water samples must be neutralised, which can be achieved with sodium thiosulphate.
Disinfection of Clinics, Wards, and Treatment Rooms
Diluted chlorine dioxide can be used in various healthcare environments, including clinics, wards, and treatment rooms, to disinfect a wide range of items such as trolleys, bedframes, commodes, patient mobility aids, handrails, workstations, floors, and walls. High-level disinfection is recommended to prevent hospital outbreaks and reduce the spread of infectious diseases.
Medical Device Decontamination
Chlorine dioxide is also used to disinfect solid-state medical devices, such as flexible nasendoscopes, transoesophageal echocardiogram probes, and diagnostic ophthalmic instruments. These devices often require decontamination in a central facility, though manual disinfection can also be performed when necessary. It is essential that all decontamination procedures are carried out by trained personnel in designated areas, with each step documented using a traceability system.
Why Choose Chlorine Dioxide?
Chlorine dioxide offers a highly effective, versatile, and safe solution for decontamination and water treatment across various industries, including healthcare, water systems, and cooling tower maintenance. Its proven track record, coupled with its ability to control microbial growth, make it an essential tool in ensuring hygiene and safety.
For more information on Chlorine Dioxide and its applications/products, please click on the following links:
Disinfection – HLD For Neonatal Equipment
High Level Disinfection for Nasal Endoscopes
High Level Disinfection for Ultrasound Probes
High Level Disinfection for Video Laryngoscopes
Surface Cleaning & Disinfectants
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