July 9, 2025
Biofilms in Industry and Water Systems
Understanding Risks, Impacts, and Regulations in Drinking Water, Cooling Towers, Food Processing, and Wastewater Treatment
Biofilm Illustration
Biofilms—communities of microorganisms attached to surfaces and embedded in a self-produced matrix—are ubiquitous in natural and engineered environments. In industrial and water systems, biofilms present both operational challenges and public health risks. They can harbor pathogens, accelerate corrosion, reduce efficiency, and complicate compliance with regulations. This article explores the role of biofilms in key sectors, the associated risks, and the regulatory landscape aimed at controlling them.
Industrial Contexts and Risks
1. Drinking Water Systems
Biofilms can develop on the inner walls of water distribution systems and storage tanks. While many of these biofilms contain harmless bacteria, they can also host opportunistic pathogens like Legionella pneumophila or Pseudomonas aeruginosa.
Risks:
Compromised water quality
Disinfectant resistance
Taste and odor problems
Increased risk of disease outbreaks
2. Cooling Towers
Cooling towers offer ideal conditions for biofilm growth—warm temperatures, high humidity, and nutrient availability.
Risks:
Corrosion and fouling of equipment
Reduced heat exchange efficiency
Amplification of Legionella, leading to Legionnaires' disease outbreaks
3. Food Processing Facilities
In food processing, biofilms form on equipment, drains, and even packaging lines, leading to potential contamination.
Risks:
Spoilage organisms like Lactobacillus or Pseudomonas
Pathogen persistence (e.g., Listeria monocytogenes, Salmonella)
Cross-contamination
Regulatory non-compliance and recalls
4. Wastewater Treatment Plants
Biofilms are both a tool and a challenge in wastewater treatment. While biofilms are intentionally used in biofilters and trickling filters to degrade organic matter, uncontrolled biofilm growth in pipes and tanks can hinder operations.
Risks:
Clogging and flow reduction
Production of malodorous compounds
Sludge bulking
Detection and Control
Detection Techniques
ATP bioluminescence for metabolic activity
Microscopy (confocal or scanning electron)
qPCR and Next-Generation Sequencing for microbial profiling
Sensor-based monitoring in smart water networks
Control Measures
Chemical Treatments
Advantages
Effective at killing microbes; easy to apply; widely used (chlorine, ozone, biocides)
Downsides / Limitations
Can form harmful disinfection byproducts; microbial resistance; corrosive to equipment; environmental concerns
Physical Removal |
Advantages
Immediate biofilm disruption; no chemicals needed (flushing, pigging, ultrasound)
Downsides / Limitations
Labor-intensive; may damage equipment; often temporary; incomplete removal of embedded microbes
Surface Modifications
Advantages
Prevents initial adhesion; long-term protection (anti-adhesive coatings, nano-texturing)
Downsides / Limitations
Labor-intensive; may damage equipment; often temporary; incomplete removal of embedded microbes
Operational Adjustments
Advantages
Low cost; optimizes existing system conditions (flow, pH, temperature)
Downsides / Limitations
Limited effectiveness alone; requires precise control; biofilms can adapt over time
Nanobubbles / Ultrafine Bubbles
Advantages
Deep penetration; stable and long-lasting; strong oxidative effects; eco-friendly; gentle on surfaces
Downsides / Limitations
High equipment cost; Emerging technology
Regulatory Landscape
Drinking Water
United States
The EPA’s Safe Drinking Water Act (SDWA) mandates microbial limits and disinfection standards.
Europe
The EU Drinking Water Directive (2020/2184) includes provisions for microbial stability and risk-based assessments.
Food Industry
United States
FDA Food Safety Modernization Act (FSMA): Focuses on preventive controls to mitigate microbial risks, including biofilms.
United States
EU Food Hygiene Package: Requires food business operators to monitor and control biofilm-forming microorganisms.
Wastewater Treatment
EPA Clean Water Act: Indirectly addresses biofilm-related issues through effluent standards and NPDES permits.
ISO 16323: Provides guidelines on managing microbial growth in water reuse systems.
FAQ
References
Costerton, J. W., Stewart, P. S., & Greenberg, E. P. (1999). Bacterial biofilms: A common cause of persistent infections. Science, 284(5418), 1318–1322.
https://doi.org/10.1126/science.284.5418.1318Hall-Stoodley, L., Costerton, J. W., & Stoodley, P. (2004). Bacterial biofilms: From the natural environment to infectious diseases. Nature Reviews Microbiology, 2(2), 95–108.
https://doi.org/10.1038/nrmicro821Flemming, H.-C., & Wingender, J. (2010). The biofilm matrix. Nature Reviews Microbiology, 8(9), 623–633.
https://doi.org/10.1038/nrmicro2415Donlan, R. M. (2002). Biofilms: Microbial life on surfaces. Emerging Infectious Diseases, 8(9), 881–890.
https://wwwnc.cdc.gov/eid/article/8/9/02-0063_articleLeChevallier, M. W., & Au, K.-K. (2004). Water treatment and pathogen control: Process efficiency in achieving safe drinking water. World Health Organization and IWA Publishing.
https://www.who.int/publications/i/item/9241562552ASHRAE. (2018). Standard 188: Legionellosis—Risk management for building water systems.
https://www.ashrae.org/technical-resources/bookstore/standard-188-2018-legionellosis-risk-management-for-building-water-systemsU.S. Food and Drug Administration. (2011). Food Safety Modernization Act (FSMA).
https://www.fda.gov/food/guidance-regulation-food-and-dietary-supplements/food-safety-modernization-act-fsmaEuropean Union. (2020). Directive (EU) 2020/2184 on the quality of water intended for human consumption.
https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:32020L2184