The direct way to WFI

Membrane-based WFI production. Three times as good.

The European Pharmacopoeia and the United States Pharmacopoeia allow various processes. Primary cause: WFI production is safe. The OSMOTRON WFI handles this task in a reliable, cost-effective, and environmentally friendly manner.
Reasons for membrane-based WFI production

The road to membrane-based WFI

Membrane-based WFI
For a long time, the only permitted method in Ph. Eur. for WFI gener­a­tion was distil­la­tion. Discus­sions and inves­ti­ga­tions on alter­na­tive processes that could also demon­strate the required levels of safety carried on for decades, notably in USP. The "interim quality" of highly Puri­fied Water was intro­duced until the change in the mono­graphs (0169) for producing WFI was published in April 2017, permit­ting alter­na­tive suit­able produc­tion methods.

Benefits of WFI from the membrane process


In a risk-based approach, BWT engineers have taken all applicable regulations into account when designing membrane-based WFI systems. In addi­tion to the Euro­pean Phar­ma­copoeia (Ph. Eur.), these include the United States Phar­ma­co­poeia (USP), the provi­sional Q&A docu­ment from the Euro­pean Medi­cines Agency (EMA), the latest draft of the revised Annex 1 as well as the ISPE manual "Herstel­lung von WFI ohne Destil­la­ti­ons­ver­fahren" (Gener­ating WFI without distil­la­tion) from the ISPE DACH Group "Pharma Wasser und Dampf" (Pharma water and steam).

The result are two standardized systems: OSMOTRON WFI and LOOPO WFI. When a tank and loops are added, they have every­thing needed for producing safe, cost-effective WFI between a potable water inlet and the point of use of systems tech­nology.



The solution for membrane-based WFI generation. Featuring a triple membrane barrier for maximum safety. The dual-stage reverse osmosis func­tion is effec­tive while the exclu­sive, pharma-compliant SEPTRON WFI module for electrodeionization and inte­grated final ultra­fil­tra­tion step ensure the best-quality WFI.


  • Costs per m³/WFI up to – 65% compared to distil­la­tion
  • Maximum safety with a triple membrane barrier
  • Fully tested and prequal­i­fied in the factory
  • Design based on risk analysis
  • Perfor­mance vali­dated via an inde­pen­dent univer­sity
Osmotron Osmotron


The ulti­mate solu­tion for storage, distri­b­u­tion, and moni­toring of WFI at ambient temper­a­ture. Safety is ensured in the crit­ical WFI tank via contin­uous ozone sani­ti­za­tion and peri­odic LOOP sani­ti­za­tion with ozone or hot water > 75° Celsius.

  • Online moni­toring of all major quality para­me­ters (TOC, conduc­tivity, bacte­rial count)
  • Contin­uous safety in the WFI tank
  • Freedom of choice in sani­tizing the distri­b­u­tion system
  • Fully prein­stalled on a compact frame
  • Precise online micro­bial count with the BWT AQU@Sense MB
Loopo Loopo

Good reasons for the membrane-based WFI generation

Good for the environment

No distillation means: Except for sanitization, no energy is used for heating and cooling. The membrane unit delivers a higher water yield instead of distillation and pretreatment. Not using salt is doubly good for the environment: simplified handling reduces the CO2 footprint considerably within transport logistics and, as no softener regeneration takes place, waste water containing chloride is also a thing of the past.

Avoiding consumption is intelligent, sustainable environmental protection.

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Good for production

Exceptional quality and safety. In WFI generation through the triple membrane barrier and removal of the microbiologically critical softener.
In production through the use of cost-effective WFI instead of PW as well as the option for additional alarm and action limits.


Good for the balance sheet

Smaller footprint. Lower investment. Lower operating costs. Cold WFI pays for itself.


360° moni­toring and main­te­nance

The right strategy to control risks.

BWT places emphasis on moni­toring and main­te­nance for constantly safe system oper­a­tion and main­taining long-​term value. The Euro­pean and the US Phar­ma­copoeia does - too. That's why we take a holistic, risk-​based approach across the whole of the life cycle. That is Quality by Design.

Relevant parameters:

AQU@View automation ideally handles the process based on requirements and the current environment (pressure, throughflow, temperature).

Sanitization and cleaning

Safety for the system. Scheduled sanitization (thermal > 80° Celsius) or cleaning (CIP) for the best WFI in the long run. Ideally clocked with operating and diagnostics data

Processes under control.

From potable water infeed via a 5 ym filter, the two stages of reverse osmosis to the final SEPTRON WFI electrodeionisation with ultrafiltration: Everything at a glance.


Monitoring operation and water quality after the various stages. Conductivity. TOC. CFU or germs. Online and offline with simple sampling


The central hub for operation and monitoring of the unit. Convenient and user-friendly. Safe thanks to the library with validated modules.


The central hub for operation and monitoring of the unit. Convenient and user-friendly. Safe thanks to the library with validated modules.

A matter of the right pretreatment

Anti­s­calant or soft­ener - which pretreat­ment is best for membrane-​based WFI produc­tion? The answer must be within the frame­work of an indi­vidual risk assess­ment.

The importance of risk assessment when designing units for ultra-pure media has been given extra weight since the approval of membrane-based non-distillation processes for generating WFI. Primary focus lies on pretreatment.

Without proper pretreatment, the hardeners dissolved in potable water quickly clog up the most important work stage, namely the reverse osmosis filtration. Two processes offer the solution: Softening through ion exchange or a dose of antiscalant.

The large surface area of the resin, along with the untreated, often standing water in the softener, represents a considerable microbiological risk. This can be safely controlled through continuous operation, use of quality components such as block valves, and frequent thermal sanitization combined with intelligent automation.

Less is more! Less space required for generation and distribution. A lower level of investment. Not to mention lower operating costs per m³/WFI whilst also offering a high degree of safety.

Exact dosage of tiny quantities of antiscalant (AS) prevents reverse osmosis being blocked. The AS remains in the concentrate with the calcium and magnesium. BWT monitored the safety of the process as part of a comprehensive long-term study in collaboration with an independent university: The microbiological risk is considerably smaller, whilst the complex handling of salt no longer takes place, meaning no chlorinated waste water is produced.

The first of two RO stages stops the majority of the microbiological load. Regular, professional cleaning of this first membrane stage is therefore of paramount importance.


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WFI systems are in the best hands during their entire life cycle with BWT AQU@Service.

Discover what makes good service. Your system is in the best hands with BWT. Receive pure trust.

In the best hands. GMP maintenance by BWT

The service engineer analyzes the process data at the beginning. He discusses results with the customer and carries out appropriate measures if necessary.

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Transparent. Exchanging seals

Seals and membranes suffer from aging. For this reason, a full and documented exchange is required periodically. A team of reliable, experienced BWT specialists organizes and carries out this complex task.

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Proven accuracy due to calibration

The reliability of automation and data recording hinges on the sensors used. Regular monitoring and calibration of all components that are critical from a quality and process perspective is therefore an integral part of any good service.

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Proven integrity

Integrity is always important in life. The same applies to units, and especially filters. Inspectors also place increased emphasis on it. BWT monitors and documents sterile filters and final ultrafiltration stages as part of the service.

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Clearly documented down to the last detail

BWT service technicians and engineers are ultra-pure media specialists in a regulated environment. They know what documentation should look like so that all questions can be clearly and satisfactorily answered during an audit or inspection.

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