Bacteria-Free Water and Water Purification Systems

By Bob Applequist, Senior Application Specialist

On August 16, 2011 in Articles

Many laboratory water purification systems for microbiology and life science applications are designed to produce bacteria-free water. Producing sterile water is relatively easy using an assortment of technologies such as Distillation, UV sterilization, sub-micron filtration and ultra filtration.

In most all situations, the simplest solution to remove all bacteria from a purified water source is the inclusion of a disposable 0.2 absolute micron filter at the terminal position of the dispensing system. This filter will insure the sterility of the water. When the filter clogs in these on-demand water production systems, it can easily be replaced.

All Labconco WaterPro® RO and WaterPro® PS Polishing Stations can accommodate a 0.2 absolute micron filter installed on the nozzle of the delivery gun or delivery nozzle. The optional Hollow Fiber Final Filter may be used with either the WaterPro RO or PS Station.

Once the sterile water exits the 0.2 micron filter, it becomes the responsibility of the laboratory operator or storage device manufacturer to ensure that water remains sterile. There are few sterile water storage devices designed for the laboratory market. Most sterile water storage devices are system components for large drug manufacturing water for injection operations.

Beyond cost and size, these products are complicated due to the follow operation requirements:

• Inlet and outlet 0.2 micron filters for sterile water
• Air Breather valve protected by a 0.2 micron filter
• UV light reactor for redundant sterilization of the stored water
• Sterilization of the water storage vessel and or water using heat and pressure
• Pump/motor for sterile water delivery

Regulatory Note: Most all laboratory water purification systems designed to produce sterile water are not intended for use in human or animal intravenous injection applications.