Legionella bacteria - a brief overview

Legionella bacteria (Legionella spp.) are water bacteria of which there are more than 40 known species. Legionella pneumophila is the most frequent pathogen of Legionnaire’s disease (legionellosis) which was named after an outbreak among American legionnaires in Philadelphia, USA in 1976. It can be life-threatening as a serious form of pneumonia. Another form of infectious disease caused by legionella bacteria is a disease which is comparable to influenza, so-called Pontiac fever. This usually progresses as a milder disease.

Legionella bacteria are typical environmental germs which multiply in single-cell organisms such as amoeba, for example. They can be found in surface water such as rivers, lakes and even in groundwater. Legionella bacteria can also be found in water pipelines. In piping systems, temperatures of 25 °C to 45 °C are ideal for legionella bacteria to multiply. The piping system biofilm also offers ideal conditions for optimum proliferation. Biofilm comprises a thin layer of mucus inhabited by microorganisms such as bacteria, legionellae, amoebae and algae.

Through water vapour arising during showers, legionella bacteria can penetrate the lungs and trigger legionellosis. The risk of infection is particularly high in public buildings such as indoor pools or in commercial buildings such as hotels and residential complexes. Transmission from one person to another is as yet unknown.

Filters - retention, usage, installation

Yes, the water filters restrain all legionella bacteria (Legionella pneumophila) thanks to their hollow fibre membrane technology. Hollow fibre membranes are individual tubes whose walls display a defined pore width. Water is directed into the tubes and then exits through the pores in the walls. 99.99999% of legionella bacteria are restrained by the pore size in the tubes.

The application time - also referred to as useful life – is generally up to 2 months. But the water quality is decisive as it can have a negative impact on useful life.

As a general rule, there is no risk of the hollow fibre membranes being clogged by water germs. Nevertheless, impurities in the water, e.g. lime residue, oil and grease films, metal residue from the pipeline system and biofilms, can reduce the flow rate.

When the hollow fibre membrane filter is used longer than the application time indicated, no warranty will be provided by Aqua free GmbH that the water is free of legionella bacteria.

The water from freshly installed filters is free of legionella bacteria. This is guaranteed by the membrane and regularly inspected within the framework of Quality Management. In the case of terminal water filters, external factors such as ambient conditions and handling can cause so-called “retrograde contamination”. This means that despite filtration, germs can be found in the water cycle during the course of routine checks.

Each filter has an absorption capacity of germs which is far higher than the typical level of contamination displayed in the pipeline network. This ensures that bacterial regrowth is prevented in the pipeline network.

Damaged or defective filters or filters whose packaging has been damaged during delivery must not be used and/or must be uninstalled.

The tap filters offered by Aqua free can be easily and swiftly mounted thanks to quick-lock coupling. The shower filters fit on any shower hose thanks to their G1/2” screw thread.

Delivery time and order quantity

After receipt of the order, the average delivery period is between two and four working days. On request and for a surcharge, we can supply you particularly fast with hollow fibre membrane filters in stock. In the event that you avail of our express delivery service, deliveries are made within 24 hours on working days. 

No, even small quantities can be ordered from us.