Fate of Groundwater Radionuclides Moving Through Small Community Systems

Transcription

1 Fate of Groundwater Radionuclides Moving Through Small Community Systems Thomas P. Ballestero University Of New Hampshire Environmental Research Group Radionuclides in Drinking Water Workshop on Implementing the Radionuclides Rule April 3rd 2007 Chelmsford, MA

2 Acknowledgements US EPA NE WTTAC VT DEC NH DES NEIWPCC and Collaborating Sites

3 Presentation Available at: or search for NE WTTAC

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5 Radioactivity in Rock in New Hampshire Igneous Rocks Two-Mica Granite

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9 The Geology and Progeny of Uranium

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14 Technical Advisory Committee (TAC) NEIWPCC NH DES VT DEC CT DEP ME DEP NE WTTAC

15 TAC Objectives Define the problem Number of systems currently affected Site specific characteristics Number of systems to be affected following implementation of the Radionuclides Rule Review QAPP

16 Site Community or Private System Population Description RI - South Kingstown CT - Morris CT - Brookfield COM COM COM VT - Colchester Private Home nursing home elderly housing adult

17 Site Community or Private System Population Description NH - Fitzwilliams NH - Canaan NH - Pelham COM NTNC NTNC units high school 100 employees shopping mall NH - Pelham Private Home NH - Pelham COM adults/1 infant 22 elderly housing

18 Radionuclide Fate and Transport Study Generic Monitoring Locations End Users Treated water Ion exchange unit Backwash S-2 Water S-1 Backwash Waste Water Regeneration Tank S-4 S-5 Storage Tank Hydropneumatic Storage D-Box Domestic Waste Water Well S-3 Septic Tank Leach Field S-6 S-7

19 Liquid Samples 1. Bedrock Groundwater 2. Treatment Unit Backwash 3. Finished Water 4. Household Wastewater Stream 5. Septic Tank Sludge/Scum/Liquid Time since pumping/backwash 6. Septic Tank Effluent - Time since pumping/backwash 7. Vadose Zone Soil Moisture 8. Shallow Groundwater Up- and Downgradient

20 Solid Samples 1. Bedrock 2. Native Soil 3. Leach Field Soil 4. Soil In plume

21 Target Analytes - Liquids Gross Alpha Analyte Gross Alpha less Radon and Uranium Gross Beta Radium Radium Uranium assuming the activity of natural Uranium is 6.77 x 10-7 Ci/gm Uranium as U 308

22 Target Analytes - Solids Analyte Gross Alpha Gross Beta Radium Radium Uranium as U 308

23 Analytical Methods - Liquids Analyte Method Detection Limit Gross Alpha EPA Gross Alpha less Radon and Uranium EPA Gross Beta EPA Radium SM 7500 Ra B 0.1 Radium EPA Ra Uranium assuming the activity of natural Uranium ASTM D is 6.77 x 10-7 Ci/gm Uranium as U 308 ASTM D

24 Analytical Methods - Solids Analyte Method Detection Limit Gross Alpha EPA (modified) Gross Beta EPA (modified) Radium SM 705 (modified) Radium EPA Ra-05 (modified) Uranium as U 308 ASTM D (modified) 10-4

25 POU/POE systems shown to remove uranium include reverse osmosis, distillation, special adsorbent media (such as titanium dioxide) and anion exchange.

26 Residuals The more effective the coagulant or adsorbent, the higher is the radioactivity in the residuals. (Clifford, 2001) Ion Exchange Softening for Radium Removal Coag-Filt w/ MnO 2 (s) for Radium Removal Fe(III) Coag-Filtration for Uranium Removal Anion Exchange for Uranium Removal 600 pci/l spent brine 20 pci/g dry resin 21,000 pci/g dry MnO 2 (s) 800 pci/g Fe(OH) 3 (s) 80,000 pci/l spent brine (30,000 BV run length)

27 Selected Sites Morris, CT Elderly Housing Middleton Springs, VT Elementary School Bedford, NH Residential Pelham, NH Apartment Complex

28 Site Bedrock Site Surficial Geology Well Depth Geology at Depth NH - Pelham Old Lawrence Road Till (Pleistocene) Well #2 575 ft Well #3 625 ft Ayer Granite NH - Bedford English Woods Till (Pleistocene) Well #1 473 ft Rangeley Formation (Silurian) NH - Bedford English Woods Till (Pleistocene) Well #4 65 ft Light gray biotitemuscovite Schist CT - Morris Ratlum Mountain Schist CT - Morris Schist Granofels VT - Middletown Springs Till Biotite/Garnet Types

29 Gross Alpha (pci/l) Ra Ra 228 (pci/l) Morris, CT Middleton Springs, VT - Short Middleton Springs, VT - Long Pelham, NH Bedford, NH Criteria 15 5

30 Radionuclides Rule Combined radium 226 and pci/l Gross alpha particle activity 15 pci/l Uranium 30 ug/l Beta particle activity 4 mrem/yr

31 Morris, CT Site

32 Morris, CT System Community Building (~100 gpd) Bedrock well Submersible pump Ion exchange ~2-5,000 gal atmospheric storage tanks 200 gal septic tank Linear leach trench

33 Ion exchange unit Treated water Backwash Water Backwash Waste Water Regeneration Tank Storage Tank Hydropneumatic Storage D-Box End Users Domestic Waste Water Well Septic Tank Leach Field

34 Backwash Waste Water Domestic Waste Water D-Box Leach Trench Field Septic Tank

35 Morris, CT Groundwater Gross Alpha (pci/l) Gross Alpha less Rn & U (pci/l) Gross Beta (pci/l) Radium 226 (pci/l) Radium 228 (pci/l) Uranium* (pci/l) Uranium (ug/l)

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37 Middleton Springs, VT Site

38 Middleton Springs, VT System Elementary School (68 students, 9 faculty, 9 staff, ~1,000 gpd) Bedrock well Submersible pump 6,000 gal atmospheric storage gal hydropneumatic storage tanks 10,000 gal septic tank 4,000 pumping tank Leach field trench system

39 End Users Storage Tank Hydropneumatic Storage Domestic Waste Water D-Box Well Septic Tank Pumping Tank Leach Field

40 school Leach Field

41 Leach Field

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50 Middleton Springs, VT Groundwater Gross Alpha (pci/l) Gross Alpha less Rn & U (pci/l) Gross Beta (pci/l) Radium 226 (pci/l) Radium 228 (pci/l) Uranium* (pci/l) Uranium (ug/l)

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52 Middleton Springs, VT Radionuclides Fate 22% Finished Water Leach Field 78%

53 Bedford, NH Site

54 Bedford, NH System Residential Community (pop. 50, 19 service connections) 2 Bedrock wells (473 ft and 65 ft) Submersible pumps Green sand filter (Manganese) Atmospheric storage Hydropneumatic storage Backwash directly to pit

55 End Users Treated water Storage Green Sand Filter Backwash Water Tank Hydropneumatic Storage Backwash Waste Water Well Surface Discharge

56 Bedford, NH Bedrock Sample Description Gross Alpha (pci/g) Gross Beta (pci/g) Radium 226 (pci/g) Radium 228 (pci/g) Uranium as U238 (mg/kg) Bedrock (Mt. 250 ft) <4 Bedrock (Mt. 400 ft) <4 Native Soil Aug <4 Native Soil Jul 2006 sample <4 Native Soil Jul 2006 sample <4

57 Bedford, NH Groundwater Gross Alpha (pci/l) Gross Alpha less Rn & U (pci/l) Gross Beta (pci/l) Radium 226 (pci/l) Radium 228 (pci/l) Uranium* (pci/l) Uranium (ug/l)

58 Well House and Treatment - Bedford, NH 58

59 Well House and Discharge Pit - Bedford, NH

60 Downgradient of Discharge Pit - Bedford, NH

61 Upgradient of Discharge Pit - Bedford, NH

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63 Pelham, NH Site

64 Pelham, NH System Apartment Complex (pop. 25, 22 service connections) 2 Bedrock wells (575 ft and 625 ft) Submersible pumps Greensand Anion Exchange Unit (Chloride form) Cation Exchange Unit (Sodium form) Atmospheric storage Hydropneumatic storage Backwash directly to pit

65 Anion Exchange Greensand Cation Exchange Backwash Waste Water Treated water Backwash Water Storage Tank Hydropneumatic Storage End Users Well Surface Discharge

66 Treatment System Maintenance Backwash: Greensand twice per week Cation Exchange unit four times per week Anion Exchange every two weeks

67 Well House and Treatment - Pelham, NH

68 Discharge to Ground - Pelham, NH

69 Discharge Pit - Pelham, NH

70 Downstream of Discharge Pit - Pelham, NH

71 Pelham, NH Bedrock Sample Description Gross Alpha (pci/g) Gross Beta (pci/g) Radium 226 (pci/g) Radium 228 (pci/g) Uranium as U238 (mg/kg) Bedrock 160 ft) <4 Bedrock (Ayer 340 ft) Bedrock (Sherburne 300 ft) <4 Bedrock (Sherburne 500 ft) <4 Native Soil <4

72 Pelham, NH Groundwater Gross Alpha (pci/l) Gross Alpha less Rn & U (pci/l) Gross Beta (pci/l) Radium 226 (pci/l) Radium 228 (pci/l) Uranium* (pci/l) Uranium (ug/l)

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74 Post-Treatment Alpha Plus Beta Pelham, NH 100% 80% 60% 40% 20% 0% Influent Softener Anion Exchange Greensand/Cation Ex. % Remaining

75 Pelham, NH Radionuclides Fate 9% 91% Finished Water Leach Field

76 Test Name Compliance Gross Alpha* Uranium Radium Radium 228 Radon EPA Standards 15 pci/l** 30 ug/l (approx 20 pci/l)*** 5 pci/l Proposed 300/4,000 pci/l (CFR Nov. 1999) *Compliance gross alpha equals the concentration of analytical gross alpha minus the concentration of Uranium ** pci/l (picocuries per liter) *** micrograms per liter (ug/l) can be converted to pci/l by multiplying the U (mg/l) by 0.67.

77 Conclusions Radioactive species tend to associate with solids (soils, sediment) Anion Exchange system very effective at removing radioactive species Leach fields have an enormous capacity for radioactivity without reaching levels of concern TENORM waste not moving in groundwater Pumping strategies may impact radioactivity level from the well

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