| Abstract |
Since becoming commercially available in the 1980s, electrodeionization (EDI) has proven to be a reliable technology for the production of high-purity water. Another term that is used to describe this technology is continuous deionization (CDI). One major advantage EDI possesses over conventional ion exchange is that it doesn’t require chemicals for regeneration. This means a reduction or even elimination of on-site acid and caustic storage and waste neutralization systems.
EDI is a very capable technology. In certain applications, EDI can completely replace a conventional full train deionization system (dual beds and mixed bed) and meet end use requirements. In some applications where finished water must be of the highest quality, EDI may still be used to replace dual beds; however, a mixed bed may follow an EDI unit to ensure enduse requirements are met and maintained. In either application EDI greatly reduces chemical regeneration hazards and expenses. Regardless of the finished water quality specifications, EDI units at a minimum must have RO permeate quality feedwater to minimize potential problems with fouling and scaling. |