You may have heard the term ‘Biofilm’ in relation to conversations surrounding bacteria and the cleanliness of water lines, however, what is biofilm, and why is its removal from water supplies so important?
Contrary to common belief, most bacteria are not “free living” – instead, they live in a self-sustaining community where they cooperate with other bacteria and are largely protected from outside influences. This is properly known as a “Biofilm” although most people would recognise it as “slime”. This makes up a large proportion of the brown deposits you see on the pipework below. Among many other bacteria, biofilm harbours the dangerous pathogens responsible for poor growth reduced liveability and poor food conversion to mention but a few.
The Microbiology of Biofilms
Bacteria are initially attracted to pipe surfaces for lots of reasons. They may be attracted to the positive charge on some inorganic surface because they often have a negatively charged outer envelope themselves, or they may arrive and settle due to gravity or water flows. There is evidence that biofilm formation is much more than a simple random physical force. Many surfaces attract and concentrate nutrients, and many bacteria have the skill to detect and follow such high concentrations (an ability called chemotaxis).
Some cells produce lots of polysaccharides which act as mucus layers, gaining a foothold and gluing others to the selected host surface, these are called the primary colonisers. This external slime gives a helping hand to other passing bacteria who add another tier of inhabitants called the secondary colonisers, who live and feed on the waste produced by the first colonisers. Before long, a thriving complex microbial community has been established inside the polysaccharide slime and it is the result of this which we refer to as biofilm.
Why is biofilm so difficult to remove?
1 – They have protection from antibiotics and biocides.
Much higher doses of antibiotics & biocides are required to kill bacteria in biofilms compared with their freewheeling relatives. At first, it was thought that the biofilm provided a complete physical barrier to efforts at destruction, but there is now evidence that the very nature of the colonies themselves provides protection. By growing in colonies, the late arrivals protect the inner cells from penetration, leaving the latter free to grow and multiply.
2 – The biofilm provides a concentration of nutrients that allows the bacteria to thrive
As negative charges are often associated with the biofilm matrix, many nutrients are drawn to settle and nutrients with negative charges can exchange with ions on the surface. This activity provides an attractive source of nourishment compared to the surrounding water.
3 – Strength in numbers
No bacterium likes to be alone for long and nearly all live with other micro-organisms for energy, carbon and other nutrients. Genetic material can be easily exchanged within the close confines of the biofilm. This increases the potential for the successful emergence of better adapted and stronger strains of bacteria.
The Lifecycle of Biofilms
Biofilm removal is the single most important part of any drinking water treatment system. If the sanitation product used does not have the ability to remove biofilm it is impossible to have a safe, pathogen free water supply. Many products – even down to the level of citrus juices – have the ability to kill free living bacteria, but only the best have the ability to penetrate and destroy biofilm, meaning that identifying and using an effective treatment in the correct way is of primary importance.
At FarmWater we are dedicated to providing the agricultural industry with effective water sanitation systems and protocols, to ensure that your farm has a consistent and reliable potable water supply. Our solutions and services are focused on the removal of biofilm and we understand what works and what doesn’t when it comes to tackling this stubborn organic substance, head on.
For more information on the services that we provide, or to read about our Chlorine Dioxide Generators, please see the pages below on our website: