Bacteria, viruses and other microorganisms may occur in both private and public water supplies. The risk is typically highest in surface water, shallow wells, poorly protected wells, storage tanks and distribution systems exposed to environmental contamination. Microbiological water treatment aims to reduce or eliminate disease-causing organisms before the water is used for drinking or industrial purposes.
Common Sources
- Surface Water and Lake Water
- Shallow or Poorly Protected Wells
- Rainfall and Flood Events
- Storage Tanks and Reservoirs
- Compromised Distribution Systems
Common Treatment Methods
- UV Disinfection
- Ozone
- Chlorination
- Membrane Filtration
- Multi-Barrier Systems
Advantages of the Multi-Barrier Approach
- Improved Reliability
- Multiple Independent Protection Barriers
- Improved Robustness During Water Quality Changes
- Common Practice in Modern Water Treatment Plants
Limitations
- Turbid Water May Reduce Disinfection Efficiency
- Different Organisms Have Different Resistance Levels
- Regular Monitoring Is Important
- Microbiological Safety Should Be Verified Through Testing
Example Treatment Trains
Lake Water
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Screen Filter
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Sand Filter
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Ozone
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Activated Carbon
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UV Disinfection
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Drinking Water
Well Water
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Particle Filter
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UV Disinfection
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Drinking Water
Raw Water
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Filtration
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UV Disinfection
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Storage Tank
Solids Removal
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Ozone
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Degassing
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UV Disinfection
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Culture Tank
Microbiological contamination is rarely visible to the naked eye. Water may appear crystal clear while still containing bacteria, viruses or other microorganisms. Regular water analysis is therefore important, particularly for private wells and smaller water systems.