Ion Exchange technology is a proven method of producing high purity softened and demineralized water, first commercialized in the 1940’s and 1950’s, and is used in most industries which require high purity water. Regeneration techniques would include Co-Current, Split-Flow Counter Current and Packed Bed designs. The highest purity water is produced with mixed bed systems which incorporate cation and anion resin in the same process unit.
Reverse Osmosis has traditionally been utilized for producing low TDS water from sea water or brackish water sources. As the technology has evolved over the past 30 years, many more applications have been developed. Heavy industry and power generating sectors now utilize Reverse Osmosis as a standard technology to produce high quality water. Membrane developments have lead to higher removal of soluble ions coupled with a reduction in operating pressures which has resulted in Reverse Osmosis becoming an economical technology for soluble ion removal.
Two separation technologies, membranes and ion exchange, are combined into one sealed, self-contained unit. The primary use of EDI has focused on RO permeate polishing. This technology is widely used in industry as a final polisher replacing traditional ion exchange units which required chemical regeneration using base and acid reagents.