Hospital MST Twente, the Netherlands


Infection control/ Legionella prevention


40 m3/hour


HG Ulfima


Medisch Spectrum Twente


City water




Large buildings like hospitals with complex piping systems are bound to be struck by problems with pathogenic waterborne bacteria like Legionella and Pseudomonas, that can pose a threat to both patients and staff. Even if the incoming water is of good quality, over time biofilm will build up in the system, providing a perfect breeding ground for such bacteria.

Once there, it has proven to be very hard and costly to eradicate. In such situations Pentair can provide its Medical Water Filter range, point-of-use Shower- and TapFilters with membranes inside. But, in a newly built situation, it is better to choose for an “at-the-source” solution, and treat all incoming water by ultrafiltration membranes.


A point-of-entry gatekeeper system will prevent any biofilm built-up, keep the building free from any waterborne bacteria issues for many years, and it will make this part of Infection Control relatively easy and much more cost-effective. Besides this, there are many other benefits. Dependent on national regulations, flushing schemes can be reduced and the minimal return water temperature to the boiler may be lowered.

All other water treatment systems like RO systems, boilers, ice machines and even water coolers will benefit from the higher feed water quality. Gatekeeper systems are typically project based, tailor made to the requirements of the facility.

other relevant information

Institutes like hospitals simply cannot be confronted with water outages, where the water supply is interrupted for whatever reason. Therefore, although the ultrafiltration gatekeeper is a very reliable system, it needs be completely redundant. That’s why Pentair supplied 2 skids with 4 X-Flow ultrafiltration modules each, both capable of servicing the entire hospital in case of breakdown situation.

This application of X-Flow ultrafiltration membranes is not limited to hospitals: all public buildings that need to  ensure safety for their patients, guests or staff, like hotels, resorts and sport facilities can benefit from a gatekeeper system.

scope of supply

2 X-line racks with 4 Aquaflex 64 membranes
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