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Mixed Bed Regeneration: Effluent Water

We are in a process of setting up a DM plant having only mixed bed exchanger. Feed water to Mixed bed is RO permeate with TDS=50 ppm. DM Plant Capacity is 160 Cu. M per Regeneration. Mixed Bed feed flow rate is 10 Cu. M per Hr.

I want to know what will be the TDS in regeneration water?

I want to use this water after neutralising the same, for gardening purpose but as pollution control board norms , TDS of effluent water should not be more than 2100 ppm.

If TDS is more than 2100 ppm after neutralising the water, how to reduce this TDS to 2100 ppm.

Please advise,

Ajay Kumar Jajoo
- Hyderabad, India
2006

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Hmmm.

I don't know a great deal about gardening, but I would use only the regenerant from the *cationic* bed (after pH adjustment of course) on your garden. The anionic bed regenerant will contain large amounts of sodium, which is undesirable in irrigation water. It causes the soil to form clods (what we used to call, as kids growing up in Queens NY, "dirt bombs") which don't till nicely.

Dave Wichern
Consultant - The Bronx, New York
2006

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Unfortunately, most of the neutralized regeneration will have a TDS concentration that is much, much higher than 2100 mg/L. However, at the end of the rinse following the regeneration, there may be a portion of the flow that is below 2100 mg/L which you could use for irrigation. This is easily automated with a conductivity controller.

Lyle Kirman
consultant - Cleveland Heights, Ohio
2006