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All EDI units require a properly designed RO to meet EDI feed water requirements. A properly designed RO is key to extending the life of the EDI modules and maintaining consistent high quality product water. The feed water requirements for an EDI are as follows:

Conductivity = 4 to 30 Microsiemens
Hardness - 1.0 ppm
Organics - 0.5 ppm TOC
Silica - 0.5
Total CO2 - 5 ppm or less
PH - 5.0 to 9.5
Temperature - 5C to 35C

If the pretreatment meets or exceeds these requirements, you can expect to get the highest quality water possible out of the EDI module. If the water quality is less than that stated above, the product water quality will be less than 17-18 Mega Ohm but may still meet USP requirements.

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PVC piping as well as sanitary piping can be provided on EDI units.

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EDI units use a Voltage Control Module to convert AC current to DC current. The input voltage to the Voltage Control Module can be either 208/240 or 440/480. The DC voltage that the EDI module uses ranges from 0 to 400V depending on the feed water quality. Good feed water quality will require less voltage to get the desired product quality.

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EDI modules use the voltage to continuously regenerate the resin. Periodic regenerations are not necessary and regeneration chemicals are not required.

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EDI modules have an approximate lifespan of 5 years. If proper care is given to the modules, the life expectancy can be greatly increased. Repeated cleanings, poor RO design and repeated hot water sanitization will all decrease the life of an EDI module.

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That is a tough question because there are numerous EDI modules on the market with different electrical consumptions. Some modules use amperage, as opposed to voltage, as the medium of ion removal. This can significantly increase the operating cost of the module. MECO's typical EDI module, operating under normal conditions, will use about 300V while drawing 2 amps per 10 GPM. This translates to about $1.00 per 8 hours per 10 GPM. This is based on an estimated $0.12/kW-hr energy cost.

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EDI units typically run at a 90% recovery rate. In certain applications it is possible to increase the overall recovery of the EDI to 99% by bringing the concentrate back to the feed of the RO unit.