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RE: Reject handling of RO

TerryF — Fri, 26 Oct 2007 17:17:10 GMT

Brine crystallisation technology is possible and works but as Bill says requires heaps of dollars. I have done a lot of research on this as i am heavily involved in 3 RO projects where concentrate disposal is a big issue.

Whilst zero discharge is possible the operating costs are huge , depending on your source of energy , quantity /quality etc i have seen numbers as high as $15 /kl of permeate (not concentrate) but this may be an extreme number.

What option is "best practice" for you will depend on many factors including:

1) Size of plant

2) Water quality

3)Local climate

4) Geographical location

5) Land availability

6)Environmental objectives.

7)Energy costs

Regards

TerryF

RE: Reject handling of RO

Bill Gaines — Fri, 26 Oct 2007 11:34:20 GMT

Absolutely. A brine concentrator followed by a crystallizer is a technically & commercially viable approach to produce a Zero Liquid Discharge system (and a few have actually done it) -- all it takes is LOADS of $$$. In reality, most all facilities add a small "pony" RO to further concentrate the primary RO reject and produce additional permeate. Beyond that, it depends on local conditions (environment, electrical and disposal costs, etc., etc., etc.). One might also consider proven technologies such as evaporation (solar & mechanical) and distillation (multiple effect, multi-stage flash, & mechanical vapor recompression) methods.

No proof, no data, and I don't operate any systems but an electrolytic unit by an Israli company has caught my eye. It'll be months (possibly years) before I have a definitive answer however.

Reject handling of RO

Membrane Worker — Fri, 26 Oct 2007 08:23:20 GMT

Can some body throw some light on this- what are the current international practices? Is evaporation and crystallisation viable commercially. Is there any other thechnology or technique- Kindly suggest a solution.