Reverse osmosis permeate passes through one or more chambers filled with ion exchange resins held between cation or anion selective membranes. Ions that become bound to the ion exchange resins migrate from the dilute chamber to a separate chamber (concentrate) under the influence of an externally applied electric field, which also produces the H+ and OH- necessary to maintain the resins in their regenerated state. Ions in the concentrate chamber are recirculated to a break tank or flushed to waste. The ion exchange beds in continuous electrodeionisaton (CEDI) systems are regenerated continuously, so they do not exhaust in the manner of ion exchange beds that are operated in batch mode (with chemical regeneration).
Hot water sanitization has been shown to be more effective than chemical sanitization for controlling microbial growth. Ease of operation, maximum reliability and low operating costs are signature features of EDI modules. HWS modules are ideal for pharmaceutical, biotechnology and other applications where chemical-free, instant hot water sanitization is desired. HWS modules produce high purity water without regeneration downtime.