Anyone regenerating DI resin?

I must have about 10 gallons of spent mix bed resin. I need to start regenerating it or toss it. Anyone doing this already and have tips? I seem to remember that the mixed bed resin can be separated by buoyancy? One sinks and the other floats in DI water? Anyone have experience? thoughts? No I haven't read the internet sites yet. I know they must give directions but thought it might be a better starting point to see what others are doing first.

As a side note I am currently running a three stage DI system with cation, anion and then mixed bed. I switched to a small commercial unit with my move to Iowa and wow was that a good decision, 1:! waste to production ration, and awesome results. The well water goes from 200 ppm to 1 ppm before hitting my DI. I recommend this to anyone with a large system because it was only about twice the money and much better performance. I may even save money in the long run with less resin use. Only down side I see is the RO cartridge is a lot more money to replace. Yeah, a single RO cartridge and a 1:1 ratio, 500 gal/day, other units that came close to this used two or three RO cartridges. I think I spent about 600$ all together, round abouts.

- Mark

 

Thanks for the information DNW. That helps. I will need to scale this up because I want to handle larger amounts of resin. The lye is NaOH. Based on the smell of anion resin I get from bulk reef they use Ammonium Hydroxide to regenerate. I wonder what is best. I wonder if you can buy acid and base at the concentrations needed so you don't have to mix or handle dangerous highly concentrated products. If I get this all worked I will let you all know. The good news is that regenerating the cation and anion from single bed resins will be much easier.

Please keep the thoughts and ideas coming.

- Mark

 

Otherwise NaOH pellets could be weighed and added to the water to reduce handling concentrated liquid. Or better use the right volume to add the contents of an entire bottle. I wonder if the different resins separate in pure RO water that would make the separation step safer, or if you need the added density of the NaOH. I am thinking of trying to separate the entire 10 gallons of resin in one large plastic drum.

 

that sounds like a good idea, using salt until the anion and cation separate. Once separated they could easily be regenerated and flushed in an extra large canister. Regenerated with acid or base and then flushed all in the canister which could then just be put in line with your system.

 

The last batch of anion resin I bought had so much ammonia smell to it that it did not seem to have been rinsed very well, this has to stress the mix bed in line after it.

 

No . Once separated I leave them separated. But no they would not precipitate, you just be contaminating the resins again with the excess acid or base left on the other resin. They need to be rinsed separately but not because of precipitation. The best way to use them is in separate cartridges. You would separate, rinse and then use them in separate canisters, cation in line before the anion and then a mixed bed to polish it off.

- Mark