Hi Tamer, Thanks for the ...

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Hi Tamer,

Thanks for the feed stream compositions.  It does make it easier to understand but it is still lacking some important information.  

However, I did undertake a speciation simulation while making a few assumptions.  It appears that the high hardness in the softener waste stream and the alkalinity in your HERO reject stream may be leading to an amount of CaCO3 scale formation (potentially at difficult levels for anitscalant).  You may need to add some sulphuric acid to destroy the alkalinity in the HERO reject stream or even consider running the ZLD system (depending on how it is set up) in seeded mode.

The above statement needs to be confirmed pending an ion balanced analysis.  I would also like to run it through our process simulation software AqMB which has the ability to take into account antiscalants performance within thermal processes.  It would also assist in investigating potential process related solutions (including running your ZLD system in seeded mode... the high calcium in one stream and high sulphate in the other may enable you to do this after some alkalinity destruction).  

Please get in contact if you have any more detailed information about these streams.

Cheers,

Matt.

matthew@saltwatersolutions.com.au

www.saltwatersolutions.com.au

www.aqmb.net

 

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Thanks Matthew very much for your detailed reply,

,for your information scale mainly occur when two feeds mixed

is it will be better to add acid on the mixed sterams!!

Also,  i use hydrex Veolia but i inject before mixing

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Hi Tamer,

Assuming the scale is in fact CaCO3 (there is still a little uncertainty on this due to some missing analysis parameters), then you'd add it to the stream containing alkalinity (HERO Reject) before mixing.  You can either destroy all the alkalinity using acid (easily calculated - just use the M-alkalinity to work out how much is required) or destroy just enough to avoid scaling (process modelling would be required to do this).  

Cheers,

Matt.

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