320m3/h Softening Plant
320m3/h Softening Plant
(OP)
Hello everyone, I am new here and this is my first post.
I am leading a project that will need 320m3/h of softened water.
INLET is fresh water from a river with 540ppm (CaCO3), de-oxygenated and filtered to 1 NTU.
my question is: Considering this important flow rate, Is any other technology apart from exchange ion resin available in the market?
thanks for reading!
I am leading a project that will need 320m3/h of softened water.
INLET is fresh water from a river with 540ppm (CaCO3), de-oxygenated and filtered to 1 NTU.
my question is: Considering this important flow rate, Is any other technology apart from exchange ion resin available in the market?
thanks for reading!





RE: 320m3/h Softening Plant
Try lime softening
RE: 320m3/h Softening Plant
Magnesium lime softening can take it down to about 75-100 mg/L CaCO3. You are adding about 1/3 more lime to get this level of hardness. What you are doing is raising the pH even more to drop out the mangnesium hardness
Then you have to drop the pH of the water down to about 8.5 in order to stop the hardness precipitation and so it is drinkable.
RE: 320m3/h Softening Plant
Another alternative would be EDR (Electro Dialysis Reversal). EDR would probably handle 1 ntu without much extra pretreatment. This technology is getting pretty rare in the market.
Regards
Ashtree
"Any water can be made potable if you filter it through enough money"
RE: 320m3/h Softening Plant
thanks for your answers, they were very useful.
sorry but I forgot to mention, design outlet quality is 10ppm as CaCO3, and PH increase is not desirable.
I will analyze the alternatives you have mentioned:
1 - lime softening (seems a good way to treat effluent from EDR or nanofiltration)
2- nanofiltration + new pretreatment (ultra filtration unit).
3- EDR (Electro Dialysis Reversal) relaxing new pretreatment
RE: 320m3/h Softening Plant
Also, you would likely use the nanofiltration or EDR downstream of the lime softening, not the other way around.
RE: 320m3/h Softening Plant
may be I am wrong but seems easier to precipitate in a concentrated solution therefore consuming less CaOH per day.
RE: 320m3/h Softening Plant
Regards
Ashtree
"Any water can be made potable if you filter it through enough money"
RE: 320m3/h Softening Plant
RE: 320m3/h Softening Plant
hoping come back later with the outcome.
RE: 320m3/h Softening Plant
You should be able to achieve the effluent quality of 10 mg/L as CaCO3 from a lime softening, filtration, water softening (ion exchange) scheme. This is a common practice in refineries.
Regarding: "@PEDARRIN2, may be for another thread, but my intention is to reuse the water from the concentrated effluent flow for another process. The removal of Ca/Mg is only to avoid future scaling problems. may be I am wrong but seems easier to precipitate in a concentrated solution therefore consuming less CaOH per day."
The only process that will remove some of the dissolved salts from solution is lime softening. The other processes that were mentioned only concentrate the removed salts into a smaller reject stream.
It may not be easier to precipitate from a concentrated solution. To do this would require additional chemicals beyond the stoichiometric quantity.
If you are interested in recycling the salt concentrated reject stream, you will looking into an evaporator process.