Uranium Removal

[chris00]

I was wondering if anyone has had any success in the removal of uranium from groundwater sources to be used for drinking water. I am aware that ion exchange resins can be effective however, the resins will eventually have to be regenerated with a NaCl brine solution or the resin would have to be replaced and disposed of.

The problems that I foresee involves disposal of a low level radioactive waste material as a solid on the resin or in liquid state in the brine solution. Would a wastewater treatment facility be able to handle the brine solution? Also where would one dispose of the low level radioactive resin material? I've checked with local state agencies to no avail.

Any thoughts or comments would be appreciated.

Cheers
Chris

 

[rbcoulter]

Found this link. Toward the middle is a list of LLW disposal sites. Don't know how current this is.

http://www.cs.virginia.edu/~jones/tmp352/projects98/group14/disposal.html#_1_2

 

[heidireichert]

Check out:

http://www.vitrification.com/

It will solve ANY heavy metal waste issue.

 

[kenvlach]

Your problem is finding the most cost-effective solution to 3 problems:
1) The actual scientific problem,
2) Permitting difficulties, what will the EPA let you do?
and
3) Public perceptions [maybe not bad if you are purifying their drinking water].

I think you will probably find your solution by canvassing other water districts around the country that have had to deal with the same problem. You should also be able to get technical help from the Dept. of Energy, Oak Ridge Nat. Lab. etc., as they process & treat more radioactivity than anyone else.

Probably, your goal is minimization of the volume of waste and to store and ship offsite. So, you want the most selective removal technique that avoids picking up hard water minerals.

My suggestion (pending better info from experienced treaters of such material): Don't use a water softener-type IX resin that is regenerated using NaCl; UCl4 is highly soluble (and brine solution is corrosive, anyway.) I suggest using a heavy metal selective strong cation bed
(check w. Rohm & Haas, etc. and other users for the best), regenerating with dilute sulfuric, neutralizing with NaOH only to pH 6 [don't want a lot of Na2SO4 solids], then adding DMTC* to precipitate heavy metals. Add a polymer flocculant only if necessary, let settle. Drain off the clear water (after testing), then transfer the sediment into a stainless steel drying vessel that you can apply some heat to [EPA pretty much always allows evaporation w/o an add-on treatment permit]. Store in SS shipping containers in a padlocked shed with a razor wire fence around it [keep out Saddam!]. I like vitrification for treatment, but it still has to go somewhere afterwards.
*Alternatively, use Na2S and precipitate as US2.

 

[GarySCWSVI]

Take a look at the following web site. It has software that can be used to calculate radioactivity accumulation on ion exchange resins and in the regenerant waste. It may be helpful to you.

http://www.epa.gov/region01/eco/wrsdp.html

 

[watrdude]

I have had success with Chloride form Anion resin installed in a small 1-2 cu. ft. exchange tank. In natural waters (pH7-10) the soluble caronate complexes of UO2(-2) are predominant anion species UO2(CO3)2(-2) and UO2(CO3)3 (-4). Monitor for Sulfate breakthrough as an indicator to pre-warn of Uranium breakthrough. Probably no need to regenerate at all, Run resin past exhaustion on alkalinity and it will still pick up the UO2 becuase of heavier molecular weight and valence (standard anion more selective for uranium). dispose of resin as haz solid. Advise you also check for Radium 226, commonly present also. Use cation resin if found. You will probably have a hard time getting any info from state agencies, at least I did. Very grey area regarding discharge, since it's a home RCRA offers no guidance. I've been told from state authorities that discharge to septic is common practice "but I didn't hear it from them". Good Source Material is Sorg, T.J. "Methods of Removin Uranium from Drinking Water," J. Am. Water Works Assoc. 80(7):105-11 (1988). Talks about IX/RO, etc. with case studies. Good Luck!

 

[dellingburn]

We have been doing a lot of work using Bone char for this appication. and there is a lot of literature out there to support this material. It is relatively cheap material and is used in the UK to remove colour from water for drinking. Obviously it does not eliminate the problem. The Bone Char with the Uranium still has to be disposed of but the Bone char does lock in the Uranium quite stongly.