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

Are All Biofilms Harmful?

No. Some biofilms are beneficial, especially in wastewater treatment and bioremediation. Problems arise when they form in unintended places or harbor pathogens.

Are All Biofilms Harmful?

No. Some biofilms are beneficial, especially in wastewater treatment and bioremediation. Problems arise when they form in unintended places or harbor pathogens.

Are All Biofilms Harmful?

No. Some biofilms are beneficial, especially in wastewater treatment and bioremediation. Problems arise when they form in unintended places or harbor pathogens.

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References