Perchlorate Removal From A Superfund Site
Perchlorate
Perchlorate has been detected in drinking water sources and surface waters throughout the United States. While perchlorate occurs naturally, it is primarily linked to releases from defense and military industries. Although it is a strong oxidant, perchlorate is highly persistent in the environment. It is known to affect the thyroid gland by inhibiting iodine uptake. The EPA has yet to establish a maximum contaminant level for the nation while California enforces a 6 ppb MCL and Massachusetts enforces a 2 ppb MCL. Clean-ups of hundreds of sites nationwide are funded by the EPA Superfund. One of the most effective methods for removing perchlorate from water is the use of perchlorate-selective anion exchange resin. We collaborated with Aerojet in Rancho Cordova, CA, to investigate our perchlorate-selective Captymer®.
The Study Report
About
The study is part of EPA funded program contract number EP-D-14-006, title: Next Generation of High Capacity Perchlorate-Selective Resins for Drinking Groundwater Treatment and is sponsored by Aerojet and conducted by its engineers at Rancho Cordova site. Two best perchlorate-selective resins, Dow PSR-2 and Purolite A532E, were used as the benchmark against AquaNano Captymer® DS-333.
Set up & Protocol
Three 2-inch columns containing each 1.4 liters of Captymer® DS-333, Purolite A532E and Dow PSR-2 resins were run in parallel. The columns were fed with the same source of contaminated groundwater from one of the wells containing 4.4 to 4,6 ppm of perchlorate. Other notable contaminates include organics, anions and cations where anions are chloride 10 ppm, nitrate 10 ppm, bicarbonate 130 ppm and sulfate 14 ppm. The tests were carried out with 3-minute EBCT to a total breakthrough. The perchlorate operation capacity of each resin then were calculated on bed volumes at 50% breakthrough.
Result
The in-house testing result of using a similar water makeup was also plotted for comparison with that of the field test. The overall results show that Captymer® DS-333 has an operational capacity advantage of 1.25-1.3 X times over those of commercial PSRs at 50% breakthrough. And, the outcome of the field test is in good agreement with one obtained in the lab. A detail analysis also indicates that the advantage increases to 1.5 time at 1% breakthrough (c.a. 40 ppb of perchlorate) in the in-house testing.