DNA Analysis of Cooling Water Biology



Cooling Water Biology DNA Analysis

Water is 24 times more efficient than air for transferring heat which is why medium to large commercial and manufacturing facilities utilize water cooled systems. With Microbe Detectives’ Cooling Water DNA Analysis, one can attain an intimate understanding of their system’s microbial community and translate that into improved protection of human health, energy efficiency and capital assets.

Problems with Microbial Fouling of Cooling Water Systems

Biological fouling is an ongoing concern and can lead to corrosion damage, losses in heat transfer efficiency and Legionnaires’ Disease. Legionella is a parasitic organism that requires the presence of certain amoeba and protozoa host organisms in a cooling water system to survive and thrive. Legionella infects and multiplies in host organisms until such point that they lyse, exploding out of the host often in thousands of new Legionella organisms, which then search for new hosts and repeat the process. Legionella hosts require the presence of biofilms (slime layers) which can form in cooling water systems and adhere to metal surfaces.

Biofilms have a diverse ecology, providing food for protozoa and amoeba. Biofilms facilitate Microbial Influenced Corrosion (MIC) and are more thermally insulating than calcium carbonate scale. When biofilms form on heat exchange surfaces this can cause significant increases in energy costs. Biofilms provide a layer of protection from biocides and disinfectants, enabling more resistant and resilient microbial communities. Standard microbial tests include the Heterotrophic Plate Count (HPC) and CDC Elite Certified Legionella culture tests. While each provide important data, neither are able inform on the true microbiome that has formed in a cooling water system nor provide predictive insights.

Advancements in Molecular Test Methods

Advancements in molecular methods (i.e., DNA analysis) have opened a new window to the microbial world of water. Our 2.0 DNA Analysis identifies and quantifies nearly all bacteria, archaea and eukarya at the genus level or above using 16S and 18S rRNA amplicon sequencing and qPCR. Shannon’s Diversity Index is used to quantify biological diversity. Key microbes shown below are identified, quantified and tracked.


  • Legionella bacteria and Legionella host organisms Acanthamoeba, Naegleria, Vermamoeba, and Tetrahymena.


  • Bacterial biofilm slime formers Bacillus, Klebsiella, Pseudomonas, and Sphingomonas,
  • Cyanobacteria slime formers Anabaena and Anacystis,
  • Fungal slime formers Candida and Trichoderma, and
  • Algal slime formers Chlorella and Scenedesmus.

Microbial Influenced Corrosion (MIC)

  • Iron Reducing Bacteria Geothermobacter, Pseudomonas and Shewanella,
  • Iron/Manganese Oxidizing Bacteria Acidiferrobacter, Acidithiobacillus, Crenothrix, Ferribacterium, Ferritrophicum, Ferrovibrio, Gallionella, Geobacter, Leptospirillum, Leptothrix, Mariprofundus, Sediminibacterium, Sideroxydans, and Sphareotilus,
  • Sulfate Reducing Bacteria Desulfatirhabdium, Desulfobacteraceae, Desulfobacterium, Desulfobulbaceae, Desulfocapsa, Desulfomicrobium, Desulfomonile, Desulfonatronospira, Desulfosporosinus, Desulfurivibrio, Desulfuromonas and Thermodesulforhabdus,
  • Sulfide Oxidizing Bacteria Clostridium, Desulfarculaceae, Desulfatibacillum, Desulfobacteraceae, Desulfomicrobium, Desulfomonas, Desulfonatronum, Desulforegula, Desulforudis, Desulfosalsimonas, Desulfovibrio, Magnetovibrio, Sulfuricella, Sulfuricurvum, Sulfurimonas, Sulfuritalea, Sulfurospirillum, Syntrophobacter, Thiobacillus, Thiorhodospira and Thiothrix, and
  • Acid Reducing Fungi Fusarium, Hormoconis and Penicillium

Biocontrol Scorecards

Biocontrol Scorecards provide actionable ratings of “Good,” “Caution,” or “Critical,” for control of Legionella, Biofilms, MIC and Total Quantities of Microbes. “Good” means microbial control is good, no action required. “Caution” means microbial control is not meeting requirements, corrective action should be taken. “Critical” means microbial control is poor, immediate corrective action is required. Examples are shown below.

cooling water protection of health
cooling water protection of capital assets

Key Benefits of Cooling Water DNA Analysis

Superior Knowledge in Microbial Control

  • Learn the true microbiome in your cooling water systems
  • Formulate the optimal microbial control strategy for achieving consistently good performance at the lowest risk and cost
  • Implement improvements
  • Measure to validate and optimize results.

Clear Actionable Guidance

Using comprehensive microbiome data, scorecards simplify guidance for the control of Legionella, Biofilms, MIC and total microbe quantities to one of three ratings “Good,” “Caution,” and “Critical.”

Achieve Superior Biocontrol

Leverage new insights to achieve superior biocontrol at lower cost.

Example DNA Dashboards for Cooling Water Biology

Dashboards show how microbial control changes over time, and how it compares to other similar cooling water systems. Below are a few examples.

cooling legionella
cooling biofilm
cooling mic
microbial influenced corrosion

Types of Cooling Water Analyzed by Microbe Detectives

Open recirculating cooling water systems that provide comfort cooling of ambient air in buildings and process cooling in manufacturing, power and other industries.



  1. Waterborne Pathogens.AWWA MANUAL M48 Second Edition, 2019
  2. Opportunistic Pathogens of Premise Plumbing.” Healthcare Environmental Infection Prevention (online), Centers for Disease Control and Prevention.
  3. Chadee, Amanda B. and Skovhus, Torben Lund. “Linking Microbiologically Influenced Corrosion to Microbiological Activity Using Molecular Microbiological Methods.” Materials Performance, May 2020.
  4. Mapping the microbiome of… everything.The Forefront, University of Chicago, November 2017.
  5. Thompson, L., Sanders, J., McDonald, D. et al. “A communal catalogue reveals Earth’s multiscale microbial diversity.” Nature, November 2017.
  6. Keele, Jacque. “Using eDNA to test for pathogens in reused water.” U.S. Department of the Interior, Bureau of Reclamation, September 2016.
  7. Ghylin, Trevor. “DNA based microbial analysis detects and locates potential contamination in distribution systems.” Journal AWWA, March 2014.

Your Microbiome Analyst will provide guidance on the DNA analysis methods that will meet your needs and objectives.