Biofilms - breeding ground for legionella

Biofilms have even been found on the inside of pipes in disinfection systems. Many disinfectants cannot or only partly render biofilms inactive - they can also not remove them. Chlorine dioxide is the only disinfectant permitted by drinking water regulations which can effectively kill off biofilms in drinking water pipes and tanks while also efficiently eliminating them. As a gas dissolved in water, it has the capability of easily penetrating biofilms and the cell walls of microorganisms thus rendering the biofilm inactive.
Gradual removal of the biofilms can be observed, in part, even from old piping systems. The build-up of resistance in connection with the use of chlorine dioxide for combating biofilms is not known.

Hazards

We encounter biofilms, including the germs and microorganisms they contain, in all lakes, puddles and in moist earth without them being a risk to us. However, there is a risk of infection through legionella when, for example, legionella bacteria are released from biofilms and, contained in water droplets (aerosols), enter the lungs.

For this reason, the following locations are considered as risk areas for the formation of biofilms:

• Showers in hotels, hospitals, old people's homes and sport facilities
• Ventilation systems with wet washers
• Cooling towers
• Wherever water is sprayed for cooling or humidification purposes
  - Coolants/lubricants used in metal-cutting processes
  - Damping down coal dust with river water
  - Sprinkler systems

Any effective measures of Legionella or propylaxis against Legionella infestation has to start at the root cause, which is the biofilm. All measures that focus on only the direct distruction of the Legionella are not longterm and therefore do not solve the problem of Legionella.