Emanation of Radon from Radium Removal Point of Use Units Prof. Abdulrahman Alabdulaaly King Abdulaziz City for Science & Technology Riyadh, Saudi Arabia WQA Aquatech USA 2010 Orlando, Florida 9 – 12 March, 2010

OVERVIEW Introduction Objective Experimental Setup Results Conclusions and Recommendations

INTRODUCTION Purpose of POU Removal of impurities, taste, color, odorRemoval of contaminants Processes used in POU Physical – Filters Absorption – Ion Exchange Separation – Reverse Osmosis Radium Removal Processes Conventional – LS, IE, RO, ED, CF.Specific – Co-prcip., Ba/Ra, HMO, RSA Major Problems of Radium Specific Adsorbents (RSA)

OBJECTIVE Assessment of radon emanation from radium specific adsorbents in the form of acrylic filters used to remove radium and ways to reduce radon levels in the treated water.

EXPERIMENTAL SETUP -Preparation of Cartridge Filters -Unit Operation.

Preparation of Cartridge Filters Three (3) Acrylic Cartridge Filters were treated with KMnO4 Cart. filters 20 in. long, 2 in Dia, 20 micron Solution Temp. : 60 oC Solution Flow rate : 1.0 gpm Duration : 20 hrs. Amount of KMnO4 used : 150, 250, 350, grams Cart. Codes : A (plain), B (150 gr.) C (250 gr), D (350 gr.)

Treatment of Cartridge filters with Potassium Permanganate (KMnO4) Pump Heater صمام Cartridge filter Cartridge housing To drain Wash water tank Electrical Magnetic stirrer Magnet KMnO4 Solution tank Valve Treatment of Cartridge filters with Potassium Permanganate (KMnO4)

UNIT OPERATION Phase I The four filters were connected in parallel Raw water contains : 33.5 pCi/L Ra 226 100 pCi/L Rn 222 Continuous water flow at 0.5 gpm for about 24 months Phase II Two identical Cart. Filters treated with 250 gr KMnO4 One filter connected to a commercial carbon filter. Second filter connected to Hydro Darco carbon filter. Water flow at 0.11 gpm for 10 min. every 3 hours (8 am - 8 pm) for 24 months.

Experimental Unit Setup Overflow Water Raw Air compressor To drain Sand Filter Cart. B Cart. A Cart. C Cart. D Micron filter Experimental Unit Setup Pump Valve Sampling valve Flow meter

RESULTS

Radon level in product water with continuous water flow 3000 2700 2400 2100 1800 1500 1200 900 600 300 Bed Volume, thousands Radon, pCi/L Raw water Radon level in product water with continuous water flow 0 400 800 1200 1600 2000 2400 Cart. A Cart. B Cart. C Cart. D

Time after resumption of water flow, min 50,000 45,000 40,000 35,000 30,000 25,000 20,000 15,000 10,000 5,000 Time after resumption of water flow, min Radon, pCi/L Radon level in product water in the first 3hrs after resumption of operation followed by 12 hrs of no flow condition 0 20 40 60 80 100 120 140 160 180 200 Cart. A Cart. B Cart. C Cart. D

Comparison of Radon level in product water for the four cart. Filters 100,000 10,000 1,000 100 10 Time after resumption of water flow, min Radon, pCi/L Comparison of Radon level in product water for the four cart. Filters after resumption of operation followed by 12 hrs no flow condition 5 10 15 20 25 30 45 60 75 90 105 120 135 150 165 180 Cart. A Cart. B Cart. C Cart. D

Radon level in product water using commercial carbon filter 3900 3600 3300 3000 2700 2400 2100 1800 1500 1200 900 600 300 0 4 8 12 16 20 24 28 32 Bed Volume, thousands Radon, pCi/L After Cart. Filter Affer Carbon Filter Raw water Radon level in product water using commercial carbon filter

Radon level in product water using HD carbon filter 6900 6600 6300 6000 5700 5400 5100 4800 4500 4200 3900 3600 3300 3000 2700 2400 2100 1800 1500 1200 900 600 300 0 4 8 12 16 20 24 28 32 Bed Volume, thousands Radon, pCi/L Radon level in product water using HD carbon filter After Cart. Filter After Carbon Filter Raw water

Results Summary Continuous flow with raw water containing 100 pCi/L of radon. Radon levels exceeded 600 pCi/L after treating about 5200 m3 (400,000 BV) of water. Radon levels after 12 hrs of no flow. The maximum conc. of radon was reached after about 12 min of flow resumption. Cart. C : 48500 pCi/L Cart. B : 33500 pCi/L Cart. D : 21000 pCi/L Radon level were stabilized after about 60 min of operation Installing carbon filters after the cart. Filter resulted in about 44% reduction in radon level.

CONCLUSIONS and RECOMMENDATIONS High levels of radon are expected to emanate from POU units designed to remove radium. The first few bed volumes of water after no flow periods contain very high levels of radon in product water. Installing carbon filters after radium removal cartridges reduces radon levels but not complete removal. It is recommended that caution be practiced while using such units due to the problem of radon emanation.

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