Biofilms, intricate communities of microorganisms including bacteria, fungi, and other microscopic entities, thrive on surfaces through a remarkable process of collaboration and self-protection. Encased within a self-produced, slime-like matrix, these microorganisms firmly anchor themselves to a variety of surfaces, from the moist lining of a water pipe to the hard enamel of our teeth. While often associated with wet environments, biofilms can also adapt to less moist conditions, revealing their resilience and versatility.
In this article, we’ll explore what biofilms are, where they’re found, the health concerns associated with them, and how to control them in building water systems.
Definition of biofilm
Biofilms are composed of different types of microorganisms, including bacterial and fungal species, that grow on and stick to the surface of a structure. A biofilm may cover natural surfaces, like teeth, or manufactured surfaces, like water pipes or water storage systems. The microorganisms that make up biofilm can be in different states, including actively multiplying, dormant, or simply associated with the biofilm structure. They can also exhibit varied phenotypes, including differences in growth rate, gene expression, and resistance mechanisms.
Formation of biofilms
The microorganisms in biofilms are often embedded in a self-produced matrix of extracellular polymeric substances, which provides structural support and protection.
This matrix contains living and dead cells and resists antimicrobial agents like sterilants, disinfectants, and antibiotics, shielding the microbial cells within.
Where biofilms are found
“Wet” biofilms typically develop in aqueous environments, including natural bodies of water like rivers and oceans, as well as manufactured surfaces like water pipes, storage tanks, and wastewater treatment facilities.
“Dry” biofilms are found in less moist environments. They can develop on surfaces in healthcare settings (e.g., operating rooms), on skin or food surfaces, and in indoor environments (e.g., HVAC systems).
Health concerns associated with biofilms
Biofilms can harbor and protect waterborne pathogens, making them more disinfectant-resistant. They are implicated in a wide range of infections, such as urinary tract infections, middle-ear infections, and implant-associated infections. Biofilms can also exacerbate chronic wounds and lung infections in cystic fibrosis patients.
Bacteria in biofilms are often more resistant to antibiotics, complicating the treatment of infections.
How biofilms affect plumbing systems
In plumbing systems, biofilms can reduce water flow, clog pipes, and corrode plumbing materials. They can also degrade water quality by harboring waterborne pathogens and releasing them into the water supply during events that alter water pressure and flow, like nearby construction or water main breaks.
Controlling biofilms in building water systems
Regular maintenance, routine flushing, and cleaning of pipes can help control biofilms. Some continuous supplemental disinfectants like copper-silver ionization can penetrate biofilms, killing the microbes contained inside. Physical treatments on the incoming water supply, like UV disinfection and sediment filtration, can help prevent microbes and nutrient-containing sediment from entering the building water system and contributing to new biofilm growth.
When designing new building water systems, plumbing engineers should implement designs that reduce stagnation and ensure consistent water flow to help prevent biofilms from forming.
Biofilms are a common and potentially harmful occurrence in building water systems. Proper maintenance and control can help prevent health concerns associated with biofilms and keep plumbing systems functioning properly. By understanding what biofilms are, where they’re found, and how to control them, organizations can ensure the safety and quality of their building’s drinking water.
