How to Deal with Biofilm in Water Systems
In this expert review the water safety specialists at Legionella Control International take a look at problematic biofilm, what it is and how to deal with it when it colonises man-made water systems.
The review explains what biofilm is and why it becomes a problem in water systems. It highlights what water system conditions to avoid, the problems faced in both new and existing buildings, the legionella risk assessment process and why this should be your starting point, and what steps are required to control or remove biofilm from water systems.
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What protects legionella and other waterborne pathogens in water systems?
It’s in every water system in every building. It’s in the pipework. It can harbour bacteria, including Legionella bacteria that can lead to Legionnaires’ disease, along with many other potentially dangerous waterborne pathogens.
We’re talking about biofilm.
What is biofilm?
Biofilm is a collection of inorganic and organic matter that collects on surfaces. It can form as a “slimy” film or as isolated patches on the surfaces of water pipes, outlets and other equipment found in water systems.
Biofilms come in many forms and crop up in many places. Man-made water systems are just one of them. They can appear in natural water sources too, along with many other surfaces and areas. We even have different types of biofilms inside our bodies.
Not something to think about over breakfast, but those responsible for managing water safety inside buildings should certainly think about their presence and how it can affect water quality, and the safety of building occupants. Biofilms can exist inside pipework, taps, showerheads and other parts of a water system, such as water storage tanks and similar structures.
Biofilms also act as a protective “hide-out” or shelter for potentially harmful bacteria, including legionella. So, the less biofilm there is, the less food these bacteria can live on, therefore reducing the chances of the bacteria colonising the water system.
Can you get rid of biofilm in a water system?
No – it’s incredibly difficult to do so completely once it’s established. Even with consistent efforts to maintain a high level of safety in a brand new water system, biofilm can and will develop. However, if the proper steps are taken and maintained, it should be kept at the lowest possible levels.
If biofilms are allowed to develop and are given ideal circumstances in which to grow, it is very difficult to manage them. Certain factors give rise to an increased risk of biofilm, including:
- Warm water, rather than water that is continually kept at hot or cold temperatures as required by the Health and Safety Executives ACOP L8
- Stagnant water, slow or no water flow, such as that found at infrequently used pipework or outlets
- Poor water hygiene that promotes the presence of nutrients that encourage bacteria to grow
Are older buildings at greater risk of biofilms forming?
It may surprise you to know that new buildings are at greater risk. When a water system is freshly installed, it may not immediately be used. Therefore, you have a lack of water flowing through the system. Even when installed, according to water safety measures and careful planning, if the system stays idle for long enough before the building comes into use, biofilms can and will form.
Biofilm is a collection of inorganic and organic matter that collects on surfaces. It can form as a “slimy” film or as isolated patches on the surfaces of pipes, outlets and other equipment found in water systems.
The same applies if a building is empty for a time. The recent Covid lockdown is a prime example of this and highlights why a fresh look at water safety is required before mothballed workplaces re-open for business.
Water safety risk factors should be lower in a new building, purely because the water system should be designed to serve the purpose it is intended for. The design should present the lowest risk of the formation of biofilm in all areas. Even if biofilm then appears, it should be easier to keep under regular control. The same would not occur if less attention was paid to the design and planning of the water system to start with.
Risk assessing water systems for legionella
A legionella risk assessment is the most important first step for the safety of all water systems and something you should carry out at the outset. A legionella assessment should typically be done at least every two years, or more often if the risk assessment calls for it, there are issues of concern or any fundamental changes occur within the system. For example, if a new hot water tank was installed, or new pipework added, the risk assessment should be done again. The same applies if any portion of the system is removed. Either way, there could be a change in risk factors that could be highlighted by the water safety assessment.
The legionella assessment should indicate areas of concern within the water system. Testing may indicate biofilms and how established they are. Ongoing management is the aim, but in some cases where biofilms have become more established, you may need to dose the system with specialist biocides that are effective against biofilm to re-gain control.
Removal of biofilm risk or ongoing management?
The ideal situation in a water system is not to allow biofilms to form to begin with. However, we have seen that this is not always possible. The next stage is to identify those areas that are of increased risk, to see if biofilm removal is possible.
For example, when a building’s usage changes, or a portion of the building becomes disused, there may be parts of the water system that also fall into disuse or irregular use. In such cases, removal of all associated pipework, taps, shower heads, and other elements of the water system in that area is the ideal scenario. If this does not happen, biofilms have an opportunity to develop in that area and this could cause additional problems.
Since the disused area will probably be connected to the rest of the water system, it could cause the biofilm to spread to other areas of the water system. This would cause the biofilms to present a far greater risk to water quality and safety over time and is something that should be carefully considered.
Clearly, good and effective management can always help mitigate the risks posed by biofilms, and other associated risks such as legionella in any water system. Make sure your approach to monitoring, maintaining, and testing any water system takes this into account. Hiring a professional risk assessor could well be the best move to assist you with this task.
Leading legionella and water safety specialists
Legionella Control International are experienced legionella and water safety specialists supporting those responsible for the control of waterborne pathogens, including legionella in the workplace. We help businesses protect their workers, customers and others from the dangers caused by water systems, helping them to meet their health and safety obligations in this specialist area.
We are experienced water safety specialists and deliver full range of services including risk assessments for legionella, pseudomonas and other waterborne pathogens. We also offer compliance auditing, water quality testing, City & Guilds training and other health and safety risk management services that help keep staff and others safe.
If you would like to speak with one of our legionella specialists about improving your risk management processes call us today on 0330 223 36 86 or contact us here …
