BA AND CA SULPHATES REMOVAL BEFORE RO ??
BA AND CA SULPHATES REMOVAL BEFORE RO ??
(OP)
hello everybody...!
i m asked by a client to recover with RO 80% of a water coming from DMF backwash + demi plant regeneration effluents (after neutralization). This water has a lot of sulphates (5000 ppm) and calcium (1250 ppm), some magnesium (550 ppm) and barium (0,5 ppm).
The RO design guy said that scaling is a big issue and that recovery can not be achieved even using the best antiscalant in the RO membranes. My question is: if the solubility constants Kps are so exceeded, so there is tendency for "self - precipitation" would it not be possible to precipitate (also adding chemicals etc) in same pre-treatment TSS clarifier the calcium sulphates, barium sulphates and then going to RO plant? any of you experienced this? or is it theory hard to put in practice? thanks a lot since now ! have a nice day !
Andrea
i m asked by a client to recover with RO 80% of a water coming from DMF backwash + demi plant regeneration effluents (after neutralization). This water has a lot of sulphates (5000 ppm) and calcium (1250 ppm), some magnesium (550 ppm) and barium (0,5 ppm).
The RO design guy said that scaling is a big issue and that recovery can not be achieved even using the best antiscalant in the RO membranes. My question is: if the solubility constants Kps are so exceeded, so there is tendency for "self - precipitation" would it not be possible to precipitate (also adding chemicals etc) in same pre-treatment TSS clarifier the calcium sulphates, barium sulphates and then going to RO plant? any of you experienced this? or is it theory hard to put in practice? thanks a lot since now ! have a nice day !
Andrea





RE: BA AND CA SULPHATES REMOVAL BEFORE RO ??
Your best process option if you want to recover the water is to use a brinc concentrator (evaporator).
http:
Recycling demineralizer wastewater is not an RO application.
RE: BA AND CA SULPHATES REMOVAL BEFORE RO ??
you mean, its better to run at , dunno, 50% recovery with simple RO system with good antiscalant rather than making it hard aiming to 80%?
pls advice thank you !!
Andrea
RE: BA AND CA SULPHATES REMOVAL BEFORE RO ??
Assume you go with a RO system, what do you plan to do with the RO reject stream? I see little value in reducing your waste volume with a 50% recovery RO. You will just be concentrating the salts further, making a smaller volume of waste but something that is more difficult and expensive to dispose of.
Trying to precipitate solids prior to the RO system is generally not a good approach because suspended solids will foul the RO unit.
For the most part, the applications for RO are for water purification not waste treatment. There are only a few specialized RO waste treatment applications that are practical/economical.
One of the RO membranes that could be used here in this application is the tubular membrane.
http://www.kochmembrane.com/prod_tubular.html
You will most likely find that it is not cost effective.
You might consider revising your water treatment scheme.
If you go with a RO treatment followed by EDI, your waste residual volumes will typically be less than the use of a demineralizer.
If you use a brine concentrator, you can recycle almost 100% of the water back as DI water. The salts are concentrated into a dry powder and easily disposed of. Waste residual problems solved.
RE: BA AND CA SULPHATES REMOVAL BEFORE RO ??
thank you
RE: BA AND CA SULPHATES REMOVAL BEFORE RO ??
RE: BA AND CA SULPHATES REMOVAL BEFORE RO ??
RE: BA AND CA SULPHATES REMOVAL BEFORE RO ??
Lime softening will reduce calcium to about 35 ppm as CaCO3, a little higher if TDS is high, but soda ash (Na2CO3) feed may be needed to ensure alkalinity is in excess of hardness, or lime softening will not be that effective. That is another topic.
So, it is good to have the component balance in mind, and consider the waste stream qualities.
So the "RO guy" may be right, too.
If you need to recover that very high TDS ion-exchange demin plant wastewater, yes, evaporator may be best, as bimr said. But that must be some very expensive water (distillate) that you get harvest with the evaporator. And, evaporator will have a very concentrated waste stream to deal with ... and the evaporator will likely be subject to extensive fouling (that calcium and barium must go somewhere).
Good luck.
//
RE: BA AND CA SULPHATES REMOVAL BEFORE RO ??
yes they must recover as
a) disposing outside not allowed
b) paying tankers not feasible also from logistic point fo view
c) evaporation pond already constructed and not possible to extend it
basically it has been a mistake of their EPC contractor which thought that 80% recovery was possible with RO just looking at the overall TDS salinity, but not considering that calcium and sulphates were accounting nearly 50% of overall salts......
Andrea
RE: BA AND CA SULPHATES REMOVAL BEFORE RO ??
my brine would enter the unit with some 62.000 TDS, mainly sulphates and calcium
thanks evbody since now !
andrea
RE: BA AND CA SULPHATES REMOVAL BEFORE RO ??
If you have a solar pond in a favorable climate, you can use only the brine concentrator step.
Not really sure what you stating. But on a power plant zero discharge application, I used RO/EDI on the make up water supply and evaporator on the wastewater
RE: BA AND CA SULPHATES REMOVAL BEFORE RO ??
RE: BA AND CA SULPHATES REMOVAL BEFORE RO ??
Contact this firm if you have any questions:
http:
What type of project are you working on?
RE: BA AND CA SULPHATES REMOVAL BEFORE RO ??
its a power plant aiming to recover water from ro brine, effluents regeneration e dmf backwash, but they want 80 % !!
RE: BA AND CA SULPHATES REMOVAL BEFORE RO ??
Beyond that, the cost to recycle the rest will be expensive.
What are you doing with the cooling tower blowdown? You should be thinking of a plant wide approach rather than looking at individual waste streams.
Use of RO on the waste streams is not practical. Assume you go with a RO system, what do you plan to do with the RO reject stream? I see little value in reducing your waste volume with a 50% recovery RO. You will just be concentrating the salts further, making a smaller volume of waste but something that is more difficult and expensive to dispose of.
If you are really serious about zero discharge. You will have to get rid of the demineralizer. Use RO on the raw water. The RO reject can then go to the cooling tower. Polish the RO effluent with an CDI. The RO/CDI to producing demineralizer water will give you the same high purity water quality with the least amount of wastes.
RE: BA AND CA SULPHATES REMOVAL BEFORE RO ??
RE: BA AND CA SULPHATES REMOVAL BEFORE RO ??
GE makes all of those products. They should be able to help you.
ht
And just what are you doing with the cooling tower blowdown? That is the biggest waste stream in a power plant.
RE: BA AND CA SULPHATES REMOVAL BEFORE RO ??
RE: BA AND CA SULPHATES REMOVAL BEFORE RO ??
RE: BA AND CA SULPHATES REMOVAL BEFORE RO ??
did you have in mind different treatment for it?
RE: BA AND CA SULPHATES REMOVAL BEFORE RO ??
I was involved in the planning stage of the water treatment system for the Guadalupe Power Plant:
http://www