1. Natural Radionuclides and Heavy Metals Partitioning during Water Treatment Processes Dr. Ashraf E. Khater King Saud University, Saudi Arabia Atomic Energy authority, Egypt http://faculty.ksu.edu.sa/Khater/default.aspx Dr. Ashraf E. Khater King Saud University, Saudi Arabia Atomic Energy authority, Egypt http://faculty.ksu.edu.sa/Khater/default.aspx

2. Outlines Aim of Work Drinking Water Purification Experimental work conclusions Introduction Results and discussion

3. The characteristics of water that mainly determine its capacity to dissolve, carry or deposit elements are its pH, temperature, redox potential, concentration and properties of dissolved salts, flow rate and residence time (Pontius 2000; Shabana and Al-Hobiab 1999). The concentration of NR and HM in water depends on several factors. These include their concentration in the aquifer rock, partial pressure of carbon dioxide, and presence of oxygen, complexing agents in the aquifer and others. Occurrence of natural radionuclides (NR) and heavy metals (HM) in the underground water is mainly due to their leaching of different salts from the bed-rocks and /or due subsurface contaminations.

4. Generally, the occurrence of radionuclides in the underground water is meanly due to the leaching of the salts from the bed- rocks. Generally, the occurrence of radionuclides in the underground water is meanly due to the leaching of the salts from the bed- rocks. Uranium is mobilized from rock by the weathering of uraninte (UO 2 ). Uranium is mobilized from rock by the weathering of uraninte (UO 2 ). The action of surface water and groundwater causes oxidative dissolution of uraninite to soluble uranyl ion (UO 2 2+ ). The action of surface water and groundwater causes oxidative dissolution of uraninite to soluble uranyl ion (UO 2 2+ ). Generally, the occurrence of radionuclides in the underground water is meanly due to the leaching of the salts from the bed- rocks. Generally, the occurrence of radionuclides in the underground water is meanly due to the leaching of the salts from the bed- rocks. Uranium is mobilized from rock by the weathering of uraninte (UO 2 ). Uranium is mobilized from rock by the weathering of uraninte (UO 2 ). The action of surface water and groundwater causes oxidative dissolution of uraninite to soluble uranyl ion (UO 2 2+ ). The action of surface water and groundwater causes oxidative dissolution of uraninite to soluble uranyl ion (UO 2 2+ ). Uranium !!!

5. Worldwide from 27 000 to 32 000 t uranium are released from igneous, shale, sandstone rocks annually by weathering and natural erosion ( Eriksson 1960; Bowen 1966; environment Canada 1983; CCME 2007 ). Worldwide from 27 000 to 32 000 t uranium are released from igneous, shale, sandstone rocks annually by weathering and natural erosion ( Eriksson 1960; Bowen 1966; environment Canada 1983; CCME 2007 ).

6. Sources of Drinking Water Surface water Ground water Ground water under the direct influence of surface water Desalinated sea water Rain water

7. Evapotranspiration Recharge Ground Water Ground Water / Surface Water Interaction Stream Lake Precipitation Plant Uptake Lake Surface Runoff Riparian Zone Wetland

8. The Drinking Water Cycle Water System Distribution System Sewer Lines Wastewater Plant Discharge Homes or Businesses Septic System Infiltration Source (aquifer, lake, etc.)

9. Ground Water UNSATURATED ZONE Ground Water UNSATURATED ZONE WATER TABLE ZONE OF SATURATION

10. Why is Groundwater Important? Groundwater supplies: – 75% of drinking water in Europe – 51% in the US – 32% in Asia – 29% in Latin America – > 60 % Saudi Arabia

11. Sources of Contamination

12. Groundwater Pollution Groundwater pollution comes from: – Storage lagoons – Septic tanks – Landfills – Hazardous waste dumps – Deep injection wells – Stored gasoline, oil, solvents, and hazardous wastes underground – can corrode and leak Pollutants in drinking water = high risk health problems – Contamination with petrochemicals (gasoline and oil) – Organic solvents (TCE) – Pesticides – Arsenic – Lead – Fluoride Groundwater cannot clean itself of degradable wastes as flowing surface water can because it flows so slowly, has much smaller amounts of decomposing bacteria, and has cold temperatures that slow down the chemical reactions that decompose waste Groundwater pollution comes from: – Storage lagoons – Septic tanks – Landfills – Hazardous waste dumps – Deep injection wells – Stored gasoline, oil, solvents, and hazardous wastes underground – can corrode and leak Pollutants in drinking water = high risk health problems – Contamination with petrochemicals (gasoline and oil) – Organic solvents (TCE) – Pesticides – Arsenic – Lead – Fluoride Groundwater cannot clean itself of degradable wastes as flowing surface water can because it flows so slowly, has much smaller amounts of decomposing bacteria, and has cold temperatures that slow down the chemical reactions that decompose waste

13. shading more light on the variation of some natural radionuclides and heavy metals concentrations through the water purification and treatment processes and shading more light on the variation of some natural radionuclides and heavy metals concentrations through the water purification and treatment processes and Studying their relationships with the physical and chemical properties (pH, EC, major anions and cations) of water during treatment. Studying their relationships with the physical and chemical properties (pH, EC, major anions and cations) of water during treatment. shading more light on the variation of some natural radionuclides and heavy metals concentrations through the water purification and treatment processes and shading more light on the variation of some natural radionuclides and heavy metals concentrations through the water purification and treatment processes and Studying their relationships with the physical and chemical properties (pH, EC, major anions and cations) of water during treatment. Studying their relationships with the physical and chemical properties (pH, EC, major anions and cations) of water during treatment. Aim of the work

14. Pretreatment plant capacity: 120,000 m 3 /d Reverse osmosis plant capacity: 100,000 m 3 /d Pretreatment system: 18Well water pumping system 1Raw water reservoir 2Pre-chlorination system 2Coagulant feed system 24Gravity filtration system 7 Transfer backwash pumping system

15. Main reverse osmosis system: 2Acid feed system 2 Anti-scalant feed system 10 Micron filtration system 13 High pressure pumping system 12Reverse osmosis skids

16. Post treatment system: 2Post chlorination system 2PH feed system 6 De-gasifier systems 1Blending system 7 Transfer pumping system

17. Particles finer than 0.1 µm (10 -7 m) in water remain continuously in motion due to electrostatic charge (often negative) which causes them to repel each other. Once their electrostatic charge is neutralized by the use of coagulant chemical, the finer particles start to collide and agglomerate (combine together) under the influence of Van der Waals's forces. These larger and heavier particles are called flocs.Van der Waals Flocculants The following chemicals are used as flocculants: [ aluminium chlorohydrate aluminium sulfate calcium oxide calcium hydroxide iron(II) sulfate iron(III) chloride polyacrylamide polyDADMAC sodium aluminate sodium silicate

18. Underground water Aeration Coagulation Pre-chlorination

19. Filtration Sand Filters Back wash Gravity filtration

20. Acidification Anti-scalant Micron Filtration

21. Reverse Osmosis 80% 20%

22. Back wash Evaporation

23. Raw water Purified water

24. Main water treatment steps Reverse Osmosis (RO) * Filtration (sand filter) * Phase 1 Phase 2 Phase 3 Aeration Input water derives from 18 drilled wells, 500-600 m depth, in a circle of 10 km 2 area. produces 10 5 m 3 /d Chemical reagents include; chlorine, Sulfate, polyelectrolyte, lime. Back wash of sand filter and RO reject are pumped to 6 evaporation ponds pH adjustment, Coagulation-flocculation Pre-chlorination Post-chlorination

25. health effects and risk Radiological TEXT Radioactive Heavy metal Chemical US Environmental Protection Agency (EPA) has classified many natural radionuclides, i.e uranium, as a confirmed human carcinogen (group A).

26. Maximum acceptable level of U in drinking water EPA has suggested that only zero tolerance is a safe acceptable limit for the carcinogenic risk from uranium and finalized a realistic regulation levels as maximum contaminant level (MCL) of 30 µg.L -1, EPA has suggested that only zero tolerance is a safe acceptable limit for the carcinogenic risk from uranium and finalized a realistic regulation levels as maximum contaminant level (MCL) of 30 µg.L -1, Canada proposed interim maximum acceptable level (IMAC) of 20 µg.L -1, and Canada proposed interim maximum acceptable level (IMAC) of 20 µg.L -1, and World Health Organization (WHO) strictly recommended a reference level of 2 µg.L -1 (Kim et al. 2004). World Health Organization (WHO) strictly recommended a reference level of 2 µg.L -1 (Kim et al. 2004).

27. Several factors control the elemental concentration in water; Their concentration in the aquifer rock, Their concentration in the aquifer rock, the partial pressure of carbon dioxide, and the presence of oxygen the partial pressure of carbon dioxide, and the presence of oxygen complexing agents in the aquifer. complexing agents in the aquifer. Also the characteristics (physical and chemical) of water mainly determine its capacity to dissolve, carry or deposit elements are pH, pH, temperature, temperature, redox potential, redox potential, concentration and properties of dissolved salts, concentration and properties of dissolved salts, flow rate and residence time ( Pontius 2000; Shabana and Al- Hobiab 1999). flow rate and residence time ( Pontius 2000; Shabana and Al- Hobiab 1999). Several factors control the elemental concentration in water; Their concentration in the aquifer rock, Their concentration in the aquifer rock, the partial pressure of carbon dioxide, and the presence of oxygen the partial pressure of carbon dioxide, and the presence of oxygen complexing agents in the aquifer. complexing agents in the aquifer. Also the characteristics (physical and chemical) of water mainly determine its capacity to dissolve, carry or deposit elements are pH, pH, temperature, temperature, redox potential, redox potential, concentration and properties of dissolved salts, concentration and properties of dissolved salts, flow rate and residence time ( Pontius 2000; Shabana and Al- Hobiab 1999). flow rate and residence time ( Pontius 2000; Shabana and Al- Hobiab 1999).

28.  The uranyl ion (UO 2 2+ ) forms stable salts and complexes with many commonly occurring anions in aquatic environment.  The chemical speciation of uranium ions in aqueous solution is quit complex because of the many possibilities of complexing reactions with most other ions  Uranium may be precipitated as insoluble UO 2 or adsorbed by clays and hydrous metal oxides.  The uranyl ion (UO 2 2+ ) forms stable salts and complexes with many commonly occurring anions in aquatic environment.  The chemical speciation of uranium ions in aqueous solution is quit complex because of the many possibilities of complexing reactions with most other ions  Uranium may be precipitated as insoluble UO 2 or adsorbed by clays and hydrous metal oxides.

29. Experimental work Sampling: Water samples; input- after aeration, after filtration (sand filter), sludge tank, reverse osmosis permit, reverse osmosis reject, output water and two samples from the evaporation ponds. Water samples were collected in 5 L capacity polyethylene containers, and transferred and kept in darkness for preservation, Sampling: Water samples; input- after aeration, after filtration (sand filter), sludge tank, reverse osmosis permit, reverse osmosis reject, output water and two samples from the evaporation ponds. Water samples were collected in 5 L capacity polyethylene containers, and transferred and kept in darkness for preservation, U, TH, K concentrations, µg.L -1, were measured using PerkinElmer model ELAN-9000 ICP-MS, U, TH, K concentrations, µg.L -1, were measured using PerkinElmer model ELAN-9000 ICP-MS, Sampling: Water samples; input- after aeration, after filtration (sand filter), sludge tank, reverse osmosis permit, reverse osmosis reject, output water and two samples from the evaporation ponds. Water samples were collected in 5 L capacity polyethylene containers, and transferred and kept in darkness for preservation, Sampling: Water samples; input- after aeration, after filtration (sand filter), sludge tank, reverse osmosis permit, reverse osmosis reject, output water and two samples from the evaporation ponds. Water samples were collected in 5 L capacity polyethylene containers, and transferred and kept in darkness for preservation, U, TH, K concentrations, µg.L -1, were measured using PerkinElmer model ELAN-9000 ICP-MS, U, TH, K concentrations, µg.L -1, were measured using PerkinElmer model ELAN-9000 ICP-MS,

30. Water physical and chemical properties such as pH, EC (electric conductivity, dS.cm -1 ), major cations (Ca, Mg and K) and major anions (CO 3, HCO 3, Cl and SO 4 ) were determine using standard methods (Al- Omran 1987) Water physical and chemical properties such as pH, EC (electric conductivity, dS.cm -1 ), major cations (Ca, Mg and K) and major anions (CO 3, HCO 3, Cl and SO 4 ) were determine using standard methods (Al- Omran 1987)

31. The variation percentage of uranium concentration in water samples relative to input water were calculated using the following equation: Δ = (C’-C) x 100/C Δ = (C’-C) x 100/C Where: C; uranium concentration in input water C’; uranium concentration in the sample Positive and negative percentages mean uranium decontamination and increment of uranium concentration, respectively (Jimenez 2002) The variation percentage of uranium concentration in water samples relative to input water were calculated using the following equation: Δ = (C’-C) x 100/C Δ = (C’-C) x 100/C Where: C; uranium concentration in input water C’; uranium concentration in the sample Positive and negative percentages mean uranium decontamination and increment of uranium concentration, respectively (Jimenez 2002) Cont.: Experimental work

32. Results and discussion

33. SamplesUranium ▲ μg/ LmBq/L Input4.0490 After Filtration4.1512 Sludge tank4.2525 R.O. Permit0.060.74-99 R.O. Reject15.7195293 Output0.172-96 Evaporation P- 1 8.3103108 Evaporation P- 2 35.1435778 Uranium concentrations (µg.L -1 ) and activity concentrations (mBq.L -1 ) in water samples and variation ratio.

34. ug/LCdCrCuHgMnNiPbSeUZn Input water (WI)0.0619.8<0.1<0.20.12.6<0.015.73.991.9 After Sand filter (ASF) 0.0118.4<0.1<0.20.13.7<0.0110.74.1414.7 Sludge WATER (thicker) (TW) 0.0519.6<0.1<0.20.13.1<0.017.84.171.9 RO permit WATER (ROP) <0.010.6<0.1<0.20.90.2 2.90.064.7 RO reject WATER (ROR) 0.0655.80.5<0.20.38.65.1612.415.750.8 final product WATER (FPW) 0.092.9<0.1<0.20.10.40.010.10.1714.4 WATER (evaporation bond) 0.1539.32.4<0.20.116.60.023935.15.5 from bond no-6 (full) 0.224.64.7<0.21.537.4<0.0171.58.286 MLC3--5 50- 100 1300- 2000 1--60.4-50701--1510--50153000

35. ug/LCdCrMnNiSeUZn Input water (WI)------- After Sand filter (ASF)-83.3-7.1-42.3883.8674 Sludge WATER (thicker) (TW)-16.7-19.2374.5- RO permit WATER (ROP) --97800-92.3-49-99147.4 RO reject WATER (ROR)-1822002311182942574 final product WATER (FPW)50-85-85-98-96657 WATER (evaporation bond)15099-536584780190 from bond no-6 (full)23324140013391154108216

39.  U and Cr concentrations were not changed before the reverse osmosis process, only variation percentage of -2 % and -7 %, respectively after filtration. While the concentrations of Ni, SE and Zn were increased !!!!!!!!  Removal percentage by reverse osmosis process was 99 for U, 97 for CR, 800 for Mn, 92 for Ni, 49 for Se, 147 for Zn. while the increment percentages in reverse osmosis reject water were ranged from 50 to 658 %  Reverse osmosis is one of the few water treatment methods which can be applied for simultaneous removal of U, Ra, Pb, Po and water salinity, i.e. water is almost completely demineralized (Huikuri et al 1998).

40.  Uranium variation percentage (removal) was 96% for the final treated water. The decrease in uranium removal percentage from that of reverse osmosis step (99%) could be due to the presence of uranium in the reagents used and/or to the dissolution of uranium associated with colloids and other substances, during water treatment processes (Jimenez 2002).  concentrations in evaporation ponds enhanced due to evaporation process where for U the variation percentages were 108 % and 778 % and will increase more by evaporation.  It is expected that uranium and other radionuclides will be accumulated to reach very high concentrations in evaporation ponds. This situation should be considered very carefully to prevent the contamination of the surrounding environment.

41. Physical and chemical properties of water samples

42.  pH values ranged from 7.6 to 8.5 where U and most heavy elements are increasingly adsorbed on oxides, clays and other silicates. The adsorbed fraction may be very close to 100 % above pH 7.  It was reported that uranium concentrations enhanced in all water that has been purified within the acidic pH (<7) (Jimeneze 2002).  It obvious that the reverse osmosis process remove not only U but also other anions and cations with variation concentration percentages more than 400% for Ca, Mg and Na, about 200 % for HCO 3 -, and about 50 % for K +.

43. Correlations between uranium concentration and physical and chemical properties of water samples

44. CdCrCuMnNiPbSeU Cr0.2 Cu1.0-0.2 Mn0.7-0.10.8 Ni0.90.41.00.7 Pb-0.80.7-0.10.2 Se0.90.31.00.71.0-0.1 U0.40.7-0.1 0.40.10.5 Zn-0.10.7-0.4-0.10.01.0-0.10.2

45. CdCrCuMnNiPbSeUZn PH-0.70.2-0.5-0.60.6-0.50.20.1 Ec0.90.21.00.81.0-0.11.00.3-0.1 Ca0.90.31.00.71.00.01.00.3-0.1 Mg0.90.31.00.71.00.01.00.3-0.1 CO3-0.2-0.6-0.50.3-0.4 -0.2 HCO30.00.6-0.20.00.70.20.60.3 CL0.90.31.00.81.00.11.00.20.0 K (me/l)0.90.21.00.81.0-0.11.00.3-0.1 Na(meq/l)0.80.20.90.81.00.11.00.2-0.1 SO4(meq/l)0.90.31.00.71.00.01.00.4-0.1

46.  There are strong correlation (correlation coefficient) between uranium concentrations and EC (0.93), Ca (0.93), Mg (0.93), Na (0.94), Cl (0.94) and SO 4 (0.92).  The correlation is good (-0.56) with pH values and weak with CO 3 (-0.39) and HCO 3 (0.32).  The strong correlation could be explained due to the demineralization of water during treatment processes especially during reverse osmosis process or due to the chemical behavior of uranium. For example, uranium can form soluble complexes in most underground waters with chloride, sulfate and under oxidizing conditions with carbonate which keep uranium in solution (Shabana and Al-Hobiab 1999).

47. Conclusions Drinking water treatment is very essential to remove many contaminants such as radionuclides and trace element. Reverse osmosis is very effective in removing radionuclides, heavy metals and other element but it de-minerlizes water. Drinking water purification residuals should be carefully considered for their possible hazardous impacts on the environment.

48. Thank you