ENVIRONMENTAL AWARENESS Time to refresh disinfection strategy A


Now that the pandemic has subsided, it’s time to review our disinfection procedures. Are we using the right disinfectants? are they being applied correctly? and do we really need all those plastic bottles? Adrian Gee-Turner, director, L’Eau, offers some insight


n issue that is starting to emerge is the microbial development of resistance to disinfectants, which may arise for a number of reasons. Microorganisms


may reside in dirt, in difficult to access places and in biofilms, where disinfectants cannot reach easily. Here, at the margins of the disinfected area, microorganisms are exposed to lower disinfectant concentrations enabling less susceptible strains to survive. Cleaning operations should therefore take place before disinfection. Equally, if disinfectants are not applied properly, spray droplets that are not fully covering a surface for example, the margins with low concentrations are dramatically increased. Also, some disinfectants are persistent in the environment; presenting microbes with ineffective concentrations that encourage resistance. The ideal disinfectant is therefore one which is highly effective at the point of application, is applied correctly, and quickly loses all of its efficacy in the environment, before reaching sewers, drains and surface waters. In order to ensure that a disinfectant is highly effective, we recommend that it should be certified to deliver a Log-4 kill of viruses. This highlights the importance of choosing the right disinfectant.


Bleach is effective at killing bacteria, fungus and viruses, but as an irritant to skin, it can cause burns and serious damage to eyes. Inhalation of its fumes can harm the respiratory tract, and the correct concentration of bleach must be used to achieve effective disinfection. Most bleach manufacturers claim 99.9% kill (Log- 3) of harmful micro-organisms, so a Log-6 disinfectant is one thousand times more effective. This means that bleach could be expected (in the right conditions) to reduce 1 million colony forming bacterial units (CFUs) to 1,000 CFUs whereas a Log-6 disinfectant would be expected to reduce the same size colony down to just one single CFU. Bleach is therefore mainly suitable for the low-cost disinfection of non-porous, unpainted surfaces such as floors and toilets. The expression ‘99.9% kill’ is used by many disinfectant manufacturers, but whilst this might sound highly effective, it isn’t. Unfortunately, this situation is further


complicated by the microbe to which the Log number relates. This is because some microbes are easier to kill than others, so beware of manufacturers that only offer 99.9% (Log-3) for bacteria. For comparison, the Nemesis eH2O (HOCl) delivers Log-6 effectivity against bacteria, Log-4 against viruses and Log-3 against spore-forming bacteria. A further advantage of HOCl (and of bleach, incidentally) is that it rapidly degrades to salt and water after application, so it is not persistent in the environment.


Plastic bottles


We are major users of single-use plastics. As a consequence, our industry is a major contributor to this ongoing global catastrophe, so we have to ask ourselves if we are happy for this to continue? The use of plastic bottles should be minimised, and they should be returned to manufacturers for re-use.


Better disinfection strategy required in healthcare


The COVID-19 pandemic highlighted the extent to which healthcare settings can contribute to the spread of infections; harming patients, health workers and visitors if insufficient attention is paid to infection prevention and control (IPC). In a recent report (1), the WHO showed that where good IPC practices are followed, 70% of those infections can be prevented.


The use of Quats


Quats, disinfectants that kill microbes by attaching to the negatively-charged surfaces of bacteria and viruses, have been popular because they provided an opportunity to formulate disinfectants to target specific pathogens in specific applications, especially where detergent action is also required. However, as outlined above, we believe cleaning operations should take place prior to disinfection.


Quats continue to raise concerns in some


circles. We believe their activity can be adversely affected by a number of things including water hardness, the active ingredients could get absorbed and there can be some health hazards. Post-pandemic, there will inevitably be a


greater demand for improved disinfection procedures and most cleaning companies


now include this in their services. However, maybe we should take this opportunity re- assess the health and environmental impacts of the products that we use?


Health and safety regulations


Under the Workplace (Health Safety and Welfare) Regulations 1992, employers have a legal duty to ensure, so far as is reasonably practicable, the health, safety and welfare of employees. Furthermore, the Management of Health and Safety at Work Regulations 1999 require employers to assess and control risks to protect their employees. A key element of this is the requirement to comply with the COSHH Regulations. The COSSH Regulations include dust, mist, vapour, fumes and chemicals. In addition to their health and environmental risks, hazardous cleaning and disinfection chemicals therefore also incur an additional administrative burden.


In many countries, employers are duty bound to consider the health and safety of their staff during the journey to work. Whilst this is not the case in the UK, responsible organisations should consider doings so.


The way forward


Potential problems occur when facility managers dictate cleaning schedules and products without the requisite training and experience. It is vitally important therefore that the trained professionals in the cleaning industry are involved in these important decisions because of the health implications for staff, visitors and cleaning staff. Environmentally friendly products that are not hazardous to human health are key, however, it is vitally important that these products are as effective, or better, than the hazardous chemicals that they replace. For these reasons, hypochlorous acid (HOCl) and catholyte have become increasingly popular in the healthcare, education and facilities management sectors. Hypochlorous acid is produced naturally by our white cells to fight infections, and it is now available as a commercial product in a stable form. With a log 6 reduction, HOCl has been shown to be one of the most effective products available, and it poses no danger to humans, pets and the environment, with no PPE required.


Conscious of the need to ensure effective coverage during disinfection, L’Eau Limited has been working with the cleaning company Twotwenty2 Limited to develop a UK-designed electrostatic sprayer, and in doing so we sought the most effective HOCl product. Following extensive research and evaluation, we chose Nemesis eH2O (500 ppm), because not all HOCL products are as effective and as stable when stored. Electrostatic sprayers should form part of all cleaning companies’ tool kit because they improve the coverage of disinfection and improve the treatment of difficult-to-access areas. All cleaning should be followed by sanitising with electrostatic sprayers, because this method maximises coverage and leaves viruses and other pathogens with no place to hide. By implementing standard procedures that ensure dwell times and coverage of all surfaces, we can create a safe environment. We cannot wait for the government to change the way we operate; we owe it to our work colleagues, our customers, our children and our planet to stop using hazardous chemicals and choose a clean, safe, effective alternative. The cleaning industry includes professional, dedicated, hard-working staff that perform a vital role in society. We are the people that understand the implications of cleaning and disinfection chemical choices, so we are the ones who will lead the way.


6 BUILDING SERVICES & ENVIRONMENTAL ENGINEER OCTOBER 2022


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