The Influence of Humic Substances and Sulfate on the removal of Perchlorate from a Groundwater by Ion-Exchange Resins

Transcription

1 DEPARTMENT OF CIVIL AND ENVIRONMENTAL ENGINEERING The Influence of Humic Substances and Sulfate on the removal of Perchlorate from a Groundwater by Ion-Exchange Resins

2 DEPARTMENT OF CIVIL AND ENVIRONMENTAL ENGINEERING Jacimaria Batista, Adriano Vieira, Frank X. McGarvey Sybron Chemicals and Purolite Provided Resin Samples

3 Treatment Technologies under Investigation for Perchlorate Removal Ion exchange Biological reduction Ozone/granular activated carbon Reverse osmosis and nanofiltration

4 Ion Exchange Technology Instantaneous correlation between ClO - 4 and ion exchange treatment due to its previous use for nitrate and arsenate removal Familiar technology to the water industry

5 Background of Perchlorate Contamination in Las Vegas LVW1 LVW3K LVW5 (Source : Adapted from Las Vegas Review Journal)

6 Las Vegas Wash at LVW5

7 RESULTS Perchlorate in Las Vegas Wash Sampling Location : LVW3K ClO4 - (ppb) Ave=87 Stdev=263 Jul-92 Nov-93 Apr-95 Aug-96 Jan-98 May-99 Date Flow (ft 3 /s) Cl4- Flow

8 Sampling Points within Lake Mead LM2 C LM5 LM8 LM4

9 RESULTS Perchlorate in Lake Mead Sampling Location: LM8 (Hypolimnion) ClO4 - (ppb) Ave = 12.3 Stdev = Lake Storage (1 ac-ft) 5 5 Jul-92 Nov-93 Apr-95 Aug-96 Jan-98 May-99 Oct- Date Cl4- Lake Storage

10 Objectives To examine the potential of ion exchange to remove perchlorate from a real water from a contaminated site in the Las Vegas Valley using different types of resins.

11 Experimental Several strong and weak-base anionic exchange resins were tested. Fixed-bed column tests were performed using cm ID glass columns with one-foot resin beds Columns were fed with the contaminated groundwater from the Las Vegas Valley. Regeneration was performed with sodium chloride. Anions were analyzed by ion-chromatography. Organic carbon was analyzed by TOC analyzer

12 RESULTS Real Water Testing

13 Average Concentration of Major Anions in the Real Water ClO 4 - Cl - NO 3 - SO 4-2 TOC Concentrations in mg/l

14 LOADING - ASB 1 Styrenic Strong Base - Trimethyl Quaternary Amine Synthetic Solution Real Water ClO4 - (mg/l) Column Utilization = 1% ClO4 -, NO3 -, TOC (mg/l) Column Util = 22.1% SO4-2 (mg/l) Perchl. Nitr. TOC Sulf.

15 LOADING - ASB 1 Styrenic Strong Base - Trimethyl Quaternary Amine Influent and Effluent TOC Concentrations TOC (mg/l) TOC-effl. TOC-infl.

16 REGENERATION - ASB 1 Styrenic Strong Base - Trimethyl Quaternary Amine Synthetic Solution Real Water ClO4 - (mg /L) % NaCl Efficiency = 37.6% ClO4 -, NO3 -, TOC (mg/l) % NaCl ε = 18.% SO4-2 (mg/l) Perchl. Nitr. TOC Sulf.

17 ASB1 PC - Real Water Styrenic Strong Base - Trimethyl Quaternary Amine Loading Regeneration ClO4 -, NO3 -, TOC (mg/l) SO4-2 (mg/l) NO3 -, TOC (mg/l) % NaCl ε =55.% ClO4 -, SO4-2 (mg/l) Col. Util = % T. Col. Util = 21% Perchl. Nitr. TOC Sulf Nitr. TOC Perchl. Sulf.

18 LOADING - ASB1 PC - Real Water Styrenic Strong Base - Trimethyl Quaternary Amine Influent and Effluent TOC Concentrations 6 45 TOC (mg/l) TOC-effl. TOC-infl.

19 LOADING - AFP 329 Styrenic Weak Base - Tertiary Amine Synthetic Solution Real Water ClO4 - (mg/l) T. Column Utilization =18.2% ClO4 -, NO3 -, TOC (mg/l) T. Col. Util = 15.5% SO4-2 (mg/l) Perchl. Nitr. TOC Sulf.

20 REGENERATION - AFP 329 Styrenic Weak Base - Tertiary Amine Synthetic Solution Real Water ClO4 - (mg/l) % NaCl Efficiency = 61.1% ClO4 - (mg/l) % NaCl ε = 44.% SO4-2, TOC (mg/l) Perchl. Sulf. TOC

21 LOADING - Macro T Acrylic Strong Base - Trimethyl Quaternary Amine Synthetic Solution Real Water ClO4 - (mg/l) Column Utilization = 53.9% ClO4 -, NO3 -, TOC (mg/l) Col. Util = % SO4-2 (mg/l) Perchl. Nitr. TOC Sulf.

22 REGENERATION - Macro T Acrylic Strong Base - Trimethyl Quaternary Amine Synthetic Solution Real Water ClO4 - (mg/l) % NaCl Efficiency = 1% TOC (mg/l) % NaCl ε = Not Calc ClO4 -, SO4-2 (mg/l) TOC Perchl. Sulf.

23 LOADING - Macro T Acrylic Strong Base - Trimethyl Quaternary Amine Influent and Effluent TOC Concentrations 6 45 TOC (mg/l) TOC-effl. TOC-infl.

24 Amount of Anions Released per Equivalent of Resin by Regeneration mg/eq ASB1 ASB2 ASB1 PC Macro T AFP 329 Nitrate TOC

25 Amount of Anions Released per Equivalent of Resin by Regeneration 3 25 mg/eq ASB1 ASB2 ASB1 PC Macro T AFP 329 Perchlorate Sulfate

26 Conclusions - Real Water 1. For two styrenic strong-base (ASB1 and ASB2), the total column utilization were only 48% and 36%, respectively, indicating that about 5% of the resin capacity was occupied by anions other than perchlorate. 2. High concentrations of SO -2 4 in the water rapidly saturated the resin. ClO - 4 was continuously removed from the water by pushing sulfate out of the resin.

27 Conclusions - Real Water 3. For a macroporous strong-base styrenic resin (ASB1 PC), about 21% of the column capacity were utilized by perchlorate. This resin exchanged considerable amount of humic acids and ClO - 4 and they could be stripped out easier from ASB1 PC than from ASB1 and ASB2 4. The capacity of the styrenic weak-base (AFP 329) for ClO - 4 was moderately affected by the presence of humic substances as compared to other resins. Humic acids were not exchanged with this resin

28 Conclusions - Real Water 5. The efficiency of the strong-base acrylic resin (Macro T) was significantly affected by the presence of humic substances contained in the real water. ClO - 4 did not exchange with this resin. This resin showed the highest TOC concentration in the regenerant brine 6. The presence of humic acids in waters may significantly affect the removal of perchlorate by ion exchange resins..

29 Research Needed To examine the effects of humic acids and other anions (e.g. sulfates, nitrate) on perchlorate removal by ion exchange resins, by using binary solutions of humic acids and different anions at different concentrations.

30 Questions and Comments