Biofilms are communities of surface attached bacteria growing inside a protective microbial secretion often called slime. Although integral to the ecology of life, biofilms are also the root cause of serious and costly problems in cooling water systems that impact:                         

  • RELIABILTY: biofilms accelerate corrosion damage and reduce flow
  • EFFICIENCY: biofilms reduce heat transfer and drive up energy costs
  • SAFETY: biofilms contribute to the spread of pathogens like Legionella

The most difficult challenge your cooling systems face
Bacteria prefer to live in biofilms, which start out microscopic in size, but can grow into visible biofouling deposits in just a matter of DAYS. Their structure protects bacteria from biocide additions, allowing them to form highly sophisticated communities that constantly adapt to become resistant to chemical treatments and mechanical removal.

Biofilms tend to form in hard to reach places. When conditions become unfavorable, they propagate by releasing bacteria into the bulk water to inhabit other surfaces. Multiple survival mechanisms make biofilms incredibly tenacious and difficult to control. Should this be a concern? Yes!

The impact of biofilm on cooling system performance
Biofilms are 4X more insulating than iron based scale deposits. So even a thin layer of biofilm on heat transfer surfaces dramatically reduces cooling efficiency and can cause production losses. For example, a mere 0.004” (0.1 mm) layer of biofilm, which is the thickness of copy paper, in a HVAC chiller reduces efficiency by 9%. For a 500-ton (1758 kW) chiller load, this can translate into over $30,000 in excess electricity costs a year with greenhouse gas emissions equivalent to operating 46 cars.

System piping and mission critical equipment including chillers, heat exchangers, and molds can also be seriously damaged by the bacteria growing in biofilms. Microbiologically influenced corrosion (MIC), which is up to 1,000 times more aggressive than generalized corrosion, is a primary cause of corrosion failure and downtime in cooling water systems.


Biofilms also play a key role in the transmission of Legionnaires’ disease by providing a protective environment for low, generally undetectable levels of Legionella entering with the source water to grow and multiply.

Addressing biofilm problems

Biofilms are extraordinarily tenacious and difficult to remove. Effective control requires specialized expertise and technologies that address the unique challenges associated with biofilm control.

Recognizing the importance of good biofilm control, Chem-Aqua's New Science and Technology Group has developed new, cutting edge technologies to help address key challenges for biofilm remediation and control.


Cooling Tower Systems Provide Ideal
Conditions for Biofilms to Form

How Biofilms Form

BIofilms Cause Serious Problems

bioeXile® Biofilm Cleaning Systems
bioeXile works with biocide additions to remove biofilms more effectively than using biocides alone or with biodispersants.

bioDART™ Biofouling Monitor
bioDART Biofouling Monitor provides a sensitive, predictive indicator of the potential to form biofilm that can be used to gauge microbial control and provide an early warning of problems.


Biofilm, Amoeba, and Legionella
Learn more about how biofilms lay a key role in the amplification of Legionella bacteria and the transmission of Legionnaires' disease.