Project 4: Legionella Protection

During this project from 2010 to 2018, our main task was the protection of warm water systems and their components. Our partners were a manufacturer of membrane filters for hospital shower heads (2010) and an Italian company for warm water systems (starting in 2018). In 2010, we conducted field tests examining virus and bacteria filters for shower heads in hospitals (Tests: Vitens Leeuwarden). Tests for warm water systems are currently conducted in the greater Milan area, Italy.

Problem and Solution

Legionella in warm water systems is a globally known issue. In hospitals they pose a great threat to patients with immunodeficiency and patients of old age. The membrane filters used in hospitals are expensive and only have a short service life. By using OxyCat® granules as a type of “police filter” at the point of entry as well as

  • protecting the interfaces between the system and its surroundings like sieves in shower heads and faucets etc.,
  • circulation through an OxyCat® cartridge in the warm water storage tank etc.

we were able to get legionella under control.


We were able to significantly increase service life. Even after a time period of more than four times the usual service life without Oxycat® there was no filter rupture with Oxycat®. First tests in warm water systems show that overall hygiene was significantly improved by Oxycat®.

Further Testing

Already in 2002, tests at De Longhi, Japan; proved high effectiveness against legionella-contamination. The 2015, tests conducted at the Swiss Federal Institute of Technology Zurich proved that activity of the granules was especially high: Even at a very high initial contamination of 3,777,000,000 cfu/100 ml (target: <100 cfu/100 ml) OxyCat® granules and ubiquitous oxidants alone were able to achieve a log reduction of 2,524. This equals a rate of way above 99 %.

Your benefit: With our new Alox catalyst, we now have a solution that is both easy to implement and cost-efficient.

The same solution can be implemented in other similar settings anytime. We provide the skills and expertise for successful implementation. There are no third-party rights.

Interested? We look forward to hearing from you! or

Facts and Figures

  • Task: Protection of warm water systems and their components against legionella, especially in risk areas
  • Project partners:
    • Dutch manufacturer of membrane filters for hospital shower heads (2010)
    • Italian company for warm water systems (starting in 2018 ff)
  • When: 2010 – 2018
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