W2 Systems offers various options for the production of SEMI grade and USP Purified water, taking into consideration feed water analysis at the particular site, as well as factors related to cost, operation and maintenance.

Electrodeionization (EDI) Water Systems ideally purify RO permeate water to a level of 3-10 micro-siemens, but depending on quality needed, up to 20 micro-siemens, without using hazardous chemicals for deionization media regeneration and without concentrate recirculation.

The EDI modules are supplied by Electropure EDI, Inc, which has the original EDI patent (1984) and have supplied over 1500 electro-deionization modules.

W2 Systems, which has served high-technology industries with standard and custom water treatment systems over 20 years, integrates the EDI modules into a turnkey skid module. The EDI System is mounted on an epoxy-coated steel frame and fabricated to allow single-point connection, to reduce field install labor cost.

Advantages over Conventional DI

• EDI does not require chemicals (as does DI resin regeneration)
• EDI does not require shutdowns
• Electropure EDI modules are the most compact per unit flow
• Provides water of consistent quality
• Requires little energy
• Economic use of capital—saves operating expense Process

W2 Systems - EDI Process Description

The electrodeionization (EDI) process uses a combination of ion-selective membranes and ion-exchange resins sandwiched between two electrodes (anode (+) and cathode (-)) under a DC voltage potential to remove ions from RO-pretreated water. Ion-selective membranes operate using the same principle and materials as ion-exchange resins, and they are used to transport specific ions away from their counter-ions. Anion-selective membranes are permeable to anions but not to cations; cation-selective membranes are permeable to cations but not to anions. The membranes are not water-permeable.

By spacing alternating layers of anion- and cation-selective membranes within a plate-and- frame module, a "stack" of parallel purifying and concentrating compartments are created. The ion-selective membranes are fixed to an inert polymer frame, which is filled with mixed ion-exchange resins to form the purifying chambers. The screens between the purifying chambers form the concentrating chambers.

The repeating element of the EDI, called a "cell-pair," is illustrated below.

Local Indicators and Controls -

1. Conductivity Monitor displays the RO and EDI water quality
2. Resistivity Elements monitors the RO and EDI water quality
3. Flow Monitoring to shutdown on low water flow
4. Pressure Regulator for EDI Inlet Pressure
5. Flow Indicators for RO and EDI Streams
6. Pressure Gauges RO and EDI Streams
7. Temperature Indicator

Control Panel

PLC-based with semi-graphic light and alarm display.

1. Supplied with all HOA switches, indicator, lights and pushbuttons
2. Power supply, transformers, and breakers are supplied
3. All wires are connected to terminal strips
4. NEMA 4X Control Panel
5. The controls, instruments, and displays are pre-wired and tested before shipment