RO

Reverse osmosis (RO) is used to reduce dissolved solids from feed waters with salinities up to 45,000 ppm TDS (total dissolved solids). Municipalities and industrial facilities are able to use RO permeate as a consistently pure drinking water supply and to transform drinking water to high purity water for industrial use at microelectronics, food and beverage, power, and pharmaceutical facilities. The technology is also very effective at removing bacteria, pyrogens, and organic contaminants.

The reverse osmosis separation technology is used to remove dissolved impurities from water through the use of a semi-permeable membrane. The RO process is the reversal of flow through a membrane from a high salinity, or concentrated, solution to the high purity, or permeate, stream on the opposite side of the membrane. Pressure is used as the driving force for the separation. The applied pressure (P) must be in excess of the osmotic pressure of the dissolved contaminants to allow flow across the membrane.

GTM
Gas transfer membrane (GTM) contactors are used for degassing liquids in many industries worldwide such as microelectronics, pharmaceuticals, and power. Used primarily for removing dissolved oxygen and carbon dioxide from water, gas transfer membranes are also well suited for specialty applications such as ammonia stripping. For over ten years, GTM contactors have gradually replaced alternate technologies such as vacuum degasifiers, forced draft degasifiers, and oxygen scavengers.

CWT uses Liqui-Cel GTM contactors manufactured by Membrana. The membrane is a polypropylene hollow fiber available in two distinct formulations to suit specific applications. The X-40 fiber is suitable for dissolved oxygen removal while the X-50 fiber is appropriate for carbon dioxide removal. While either fiber will remove dissolved oxygen and carbon dioxide, they operate more efficiently when matched to the specific application. The X-IND is the third fiber, which is actually an X-50 fiber in a less expensive housing, making it very cost effective for carbon dioxide removal in the makeup portion of an application for the microelectronics or power industries.

Major Benefits of CWT GTM Technology include:
Cost effectiveness (or efficiencies) of redundant units
Lower installation cost
Lowest total cost of ownership
Performance equal to or better than other technologies
Smaller footprint compared to degasifier towers
Depending on the desired degree of gas removal, one of the following operating modes can be chosen:

Sweep mode - A sweep gas (nitrogen or air) is applied to the lumen side (inside) of the membrane.
Vacuum mode - A vacuum is pulled on the lumen side of the membrane to effect stripping of the dissolved gas.
Combo mode - A combination of sweep gas and vacuum are applied to the lumen side of the membrane. This mode of operation is capable of providing effluent dissolved oxygen levels down to <1 ppb (using N2 as the sweep gas).
A selection of representative customers using CWT GTM: