If you need different water qualities (because of different applications, for example) but have limited space in your laboratory, a combined water purification system might be a good option. Another reason to consider a combined water purification system is when you need ultrapure water directly from a tap water source.

The most notable benefit of a combined water purification system is that it can produce ultrapure water directly from tap water. It also saves laboratory space by combining a pretreatment and polisher system into one. In addition to ultrapure water, a combined water purification system also gives you access to either pure or RO water. Having a combined system also leads to less maintenance (one system instead of two).

By combining a pretreatment system and a polisher system into one, you will produce two different qualities of water (ultrapure and RO) with one system. The main difference of combining two systems into one is the recommended daily volume. The individual respective water purification systems usually have larger cartridge capacities and therefore have a higher recommended daily volume.

A combined water purification system produces two different water qualities suitable for a wide range of applications. The ultrapure water produced can be used for applications that require ultrapure water, while the pure or RO water is suited to general laboratory or feed water applications. If your critical applications have specific requirements, make sure your combined water purification system has the necessary added purification technologies to accommodate the needs, such as UV or ultrafiltration.

An intermediate water storage tank is needed in combination with a combined water purification system. As the pretreatment step usually consists of an RO module (and perhaps other filtration-based steps), the flow rate after pretreatment is quite low. To utilize the purified water after pretreatment with sufficient pressure and flow rate, an intermediate storage tank is needed before the polishing step.

An intermediate storage tank is needed with a combined water purification system between the pretreatment stage and the polishing cycle. Depending on the storage tank itself, there will generally be an option to dispense pure or RO water from the storage tank - either directly from the tank (via tubing or similar) or by connecting a remote dispenser.

A combined water purification system consists of a pretreatment stage and a separate polisher stage in one system. The pretreatment step usually consists of a reverse osmosis module (RO water) prior to an optional deionization cartridge (ASTM Type 2 water).

Additional steps can include activated carbon and/or depth filters before the RO module to protect and extend its life cycle. After pretreatment, intermediate water storage is needed before returning the pretreated water to the polisher cycle. The following polisher step then includes another deionization cartridge and activated carbon before being dispensed via a final point of use filter. Additional UV lamp or ultrafiltration might be included as well.