Sterile filtration

Your reliable companion for infection prevention*

Most microorganisms found in drinking water are harmless to healthy individuals. But in the hospital, they pose a serious danger, especially for intensive-care patients. Thanks to high-tech in the area of sterile filtration, we help you to reduce the risk of waterborne nosocomial infections in your medical facility.

*This content is not valid for the U.S. market.
For an overview of our products for the U.S. market,
please visit our U.S. website.

Creation of biofilm in drinking water pipes

Drinking water is probably subject to more controls in Germany than any other foodstuff and has to comply with strict standards. After the water has been treated, its chemical and microbiological parameters are tested at the waterworks to ensure it meets the quality requirements specified by law.

However, conditions change when drinking water is fed into the household water system. Here, the water pressure is lower than in the main supply pipe; drinking water is heated or used irregularly and stays in the pipes for days or weeks without moving. When fitting the piping, a small number of bacteria can enter the water system, settle on the internal walls of the pipes and multiply very well under ideal conditions. Water experts call these deposits biofilm. Biofilm is a kind of bacterial community. The bacteria use this film to protect themselves from heat and chemicals (e.g. chlorine). It is nearly impossible to remove them completely by flushing, disinfecting, etc.

Therefore, Germany's Drinking Water Ordinance has established standards for water quality. One drop of drinking water is allowed to contain up to 100 pathogens. This amount of pathogens is not dangerous to healthy individuals. They can drink the water without any worries and use it for daily personal hygiene. However, for people who have a weak immune system due to illness or who are not yet fully grown, such levels of pathogens can lead to a serious health danger. This is why medical facilities must meet higher standards on water quality.

Special challenges at medical institutes

Nurses, hygiene specialists and doctors face the serious challenge of the spread of gram-negative, pathogenic bacteria – a challenge that is almost impossible to overcome without a comprehensive prevention plan.

Tests show that contaminated water causes up to 50 percent of Pseudomonas aeruginosa–related nosocomial infections in intensive care units. The drinking water system is therefore a relevant and underestimated infection reservoir for Pseudomonas aeruginosa.1 To minimize this risk as much as possible, the German Federal Environment Agency, the Robert Koch Institute and the Hygiene in Hospital & Practice working group give numerous recommendations for the safe handling of drinking water in hospitals.

Sterile filtration as an important pillar of infection prevention

In the past 15 years, sterile water filtration has become firmly established as an important pillar of infection prevention.2,3 Medical CE-marked sterile filters serve to prevent infection and reduce the risk of nosocomial infection due to waterborne pathogens. In a recent study, Pseudomonas aeruginosa was found in 8 percent (11/136) of the water outlets examined at a liver transplant center. After the installation of point-of-use filters, Pseudomonas aeruginosa, legionella and mycobacteria were no longer found in tap water samples. In addition, the rate of colonization/infection due to gram-negative, rod-shaped bacteria was reduced by 47 percent.4

To ensure successful infection prevention, use a point-of-use filter placed on the faucet or shower head for the sterile filtration of drinking water. The filter should satisfy the following requirements:

• Bacterial retention as required by ASTM F838  >7 log per square centimeter (Brevundimonas diminuta)
• Bacteriostatic properties of the filter housing throughout the period of use
• A filter surface that can be wiped down to disinfect
• A CE-marked medical device

Second generation of point-of-use sterile filters

Backed by 15 years of experience and with the help of ion-supported technology, i3 Membrane has been able to develop compact, high-performance sterile filters. With the second generation of our sterile filters, we are setting new standards in infection prevention. Precision engineering has further improved the high-performance membrane at the heart of our filters. So, even when the water quality is poor (e.g. due to rust, iron or silt deposits in the pipes), sterile filtration with a high flow rate is assured.

We have been able to perfect the bacteriostatic properties of the filter housing by using new technologies that enable the filter to counteract retrograde contamination and biofilm formation throughout the entire period of its use. What's more, the sterile filter ensures unlimited safe use thanks to its compact design and the laminar-angled direction of the water jet.

Sterile filters for the reprocessing of medical devices

When reprocessing medical devices such as endoscopes, which are used within the human body, high-quality cleaning and disinfection in accordance with DIN EN ISO 15883 are vital. Particular attention needs to be given to meeting the specifications for the quality of the water used for final rinsing, to ensure residues from cleaning and disinfectant solutions are removed as completely as possible from the exterior and interior of the endoscope.

In their specifications for hygiene in the reprocessing of medical devices, the Commission for Hospital Hygiene and Infection Prevention (KRINKO) at the Robert Koch Institute (RKI) and the German Federal Institute for Drugs and Medical Devices (BfArM) recommend the use of validated processes. They also provide details of threshold values for water quality, with the aim to avoid the transmission of microorganisms on reprocessed endoscopes.

With our safe sterile filters for use on cleaning guns for rinsing medical devices (e.g. endoscopes), as well as our inline filters serving as a barrier on the inlet pipe of medical devices that use water (e.g. birth pools and cleaning and disinfection devices for endoscopes), we give you support for infection prevention in your medical facility.

Certified quality management

As a manufacturer of medical devices, we have a quality management system that is certified in accordance with DIN EN ISO 13485. This means i3 Membrane complies with strict requirements regarding the safety and reliability of our products and services, as well as the risk minimization at product design and production.

i3 Medical film series

Watch now: Successful and sustainable infection prevention with i3 Membrane filters Watch now: Opportunistic pathogens Watch now: Contamination pathways
Watch now: Features & benefits of i3 water filters Watch now: i3 trackApp Watch now: Use of i3 filters


  • 05.12.2022

    Resistant bacteria pose increasing infection risk (German Edition) New Lancet analysis paints dramatic picture

    The WHO predicts that, by 2050, 10 million people per year will die as a result of resistant pathogens.

  • 04.10.2022

    Infection prevention is climate protection (German Edition) Infection prevention saves on waste

    Point-of-Use water filters can improve the carbon footprint of hospitals.*

  • 01.04.2022

    Interrupting the contamination pathways is crucial (German Edition) Disruption by sustainable barriers

    Why reassessment of the use of terminal infection prevention filters in hospitals is urgently needed.*

  • 27.05.2021

    Roll up one's sleeves (German Edition) A speach for state of knowledge

    „Health at a Glance" is a publication of OECD on the european state of health in 2020.


  • 08.03.2021

    Small label, great benefit (German Edition) Why are CE-marked medical devices important for the clinical routine?*

    The CE mark for medical devices requires a high degree of product safety, according to EU regulations.*

  • 11.09.2019

    Point-of-Use water filters* (German Edition) In everyday clinical practice: on risks and side effects

    In hospitals, withdrawal points for water represent a special interface between technical and hygienic requirements.

  • 05.06.2019

    On the paths of water-associated bacteria (German Edition)

    Examinations from numerous samplings show that clinics have a much higher excess frequency particular with Pseudomonas aeruginosa, than other public institutions.

  • 08.05.2019

    Modern and high quality separation technology (German Edition)

    i3 Membrane is quickly becoming a specialist in high-quality separation technology in the fields of medical care, biotechnology and environmental analysis.

  • 21.03.2019

    Gram-negative germs in hospitals (German Edition) Where do they come from and why is it not just the water's fault?

    Most microbes contained in fresh tap water are harmless for healthy people. For people with weakened immune systems the microbes present in tap water can be dangerous.



1 Recommendation by Deutsche Gesellschaft für Krankenhaushygiene: "Gesundheitliche Bedeutung, Prävention und Kontrolle Wasser-assoziierter Pseudomonas aeruginosa-Infektionen" in HYGIENE & MEDIZIN, 41st Edition, Supplement 2, 2016, p. 6

2 Recommendation by Deutsche Gesellschaft für Krankenhaushygiene: "Anforderungen an die Hygiene bei der medizinischen Versorgung von immunsupprimierten Patienten" Federal Health Library 2010, 53:357–388; Online publication: March 20, 2010 © Springer-Verlag 2010, p. 366

3 Recommendation by Deutsche Gesellschaft für Krankenhaushygiene: "Gesundheitliche Bedeutung, Prävention und Kontrolle Wasser-assoziierter Pseudomonas aeruginosa-Infektionen" in HYGIENE & MEDIZIN, 41st Edition, Supplement 2, 2016, p. 16

4 Zhou, Z.Y.; Hu, B.J.; Qin, L.; Lin, Y.E.; Watanabe; H.; Zhou, Q.; et al. "Removal of waterborne pathogens from liver transplant unit water taps in prevention of healthcare-associated infections: a proposal for a cost-effective, proactive infection control strategy", Clinical Microbiology and Infection 2013, - As of August 13, 2020

*Refers to the non-U.S. version of the i3 ONE and i3 TWO

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