Treatment of perchlorate-contaminated groundwater using highly selective, regenerable ion-exchange technologies.
Treatment of perchlorate-contaminated water using highly selective, regenerable ion-exchange and perchlorate-destruction technologies was demonstrated at a field site in California. Four treatment and four regeneration cycles were carried out, and no significant deterioration of resin performance was noted in 2 years. The bifunctional resin (Purolite A-530E) treated about 37,000 empty bed volumes (BVs) of groundwater before a significant breakthrough of perchlorate occurred at an average flow rate of 150 gpm (or 1 BV/min) and a feed perchlorate concentration of about 860 microg/L. Sorbed perchlorate (approximately 20 kg) was quantitatively recovered by eluting with as little as 1 BV of the FeCl3-HCl regenerant solution. The eluted ClO4- was highly concentrated in the third quarter of the first BV of the regenerant solution with a concentration up to 100,000 mg/L. This concentrated effluent greatly facilitated subsequent perchlorate destruction or recovery by precipitation as KClO4 salts. High perchlorate destruction efficiency (92-97%) was observed by reduction with FeCl2 in a thermoreactor, which enabled recycling of the FeCl3-HCl regenerant solution, thereby minimizing the need to dispose of secondary wastes containing ClO4-. This study demonstrates that a combination of novel selective, regenerable ion-exchange and perchlorate-destruction and/or recovery technologies could potentially lead to enhanced treatment efficiency and minimized secondary waste production.
Gu
Baohua
B
Environmental and Chemical Sciences Divisions, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA. gubl@ornl.gov
Brown
Gilbert M
GM
Chiang
Chen-Chou
CC
D011232:Chemical Precipitation; D002712:Chlorides; D005290:Ferric Compounds / Q000737:chemistry; D006851:Hydrochloric Acid / Q000737:chemistry; D007475:Ion Exchange Resins / Q000737:chemistry*; D007700:Kinetics; D010472:Perchlorates / Q000737:chemistry / Q000302:isolation & purification*; D017680:Potassium Compounds / Q000737:chemistry; D013696:Temperature; D014865:Waste Disposal, Fluid / Q000295:instrumentation / Q000379:methods; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*; D018508:Water Purification / Q000295:instrumentation / Q000379:methods; D014881:Water Supply
D002712:Chlorides; D005290:Ferric Compounds; D007475:Ion Exchange Resins; D010472:Perchlorates; D017680:Potassium Compounds; D014874:Water Pollutants, Chemical; C009006:potassium perchlorate; D006851:Hydrochloric Acid; C024555:ferric chloride