Why is tank disinfection important?
Water storage and tank systems can become a breeding ground for microorganisms such as bacteria, viruses, and algae over time. Standing water is particularly problematic as it creates ideal conditions for germ growth. To ensure safe water quality, various disinfection methods are used – including UVC disinfection. But can UVC alone ensure complete tank disinfection?
How does UVC disinfection work in tanks?
The UVC technology uses ultraviolet light with a wavelength of 254 nm to kill microorganisms. By destroying the DNA and RNA, the germs lose their ability to reproduce. There are two basic applications for tank disinfection:
- Direct irradiation in the tank: UVC lamps are installed inside the tank to irradiate the water directly.
- Flow disinfection: The water is passed through a UVC chamber when exiting the tank before it is used.
Challenges of UVC disinfection in tanks
Although UVC is an effective disinfection method, there are some limitations in tank disinfection:
- Low UVC transmission: Water often contains particles, turbidity, or high levels of dissolved substances that reduce UVC permeability. This reduces irradiation efficiency.
- No residual effect: UVC only works where the light directly hits the microorganisms. Biofilms on tank walls or in pipelines remain unaffected.
- Shadow formation: In larger tanks or with unfavorable placement of UVC lamps, shadow zones can form where germs can survive.
Optimal combination: Tank and flow disinfection
Since UVC irradiation alone in the tank is often not sufficient, we recommend a combination of tank disinfection and flow disinfection:
- UVC irradiation in the tank: Reduces germ growth in standing water.
- Filtration to improve UVC transmission: Pre-filtration removes particles that impair UVC effectiveness.
- Flow disinfection at water outlet: Ensures reliable germ-free water before it is used.
Comparison with other tank disinfection methods
Chemical disinfection (e.g., chlorine, chlorine dioxide, hydrogen peroxide)
Chemicals offer a long-lasting residual effect and also reach biofilms.
- Advantages: Long-term germicidal effect, effective against biofilms.
- Disadvantages: Changes in taste and smell of the water, risk of by-products, increased maintenance effort.
Ozone Disinfection
Ozone is a strong oxidizing agent that quickly destroys germs and breaks down organic substances.
- Advantages: Very effective disinfection, no long-term chemical residues.
- Disadvantages: Complex technology with high energy consumption, no depot effect.
Conclusion
UVC disinfection is an environmentally friendly and chemical-free method for tank disinfection, but with limitations regarding transmission, shadow formation, and depot effect. The best solution is a combination of tank and flow disinfection, possibly supplemented by pre-filtration. This ensures that the water is not only germ-free in the tank but also when leaving it, maintaining high water quality.