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Uranium

Reverse Osmosisreverse osmosis treatment picture

  The reverse osmosis (RO) system is actually a combination of processes that is usually installed under the kitchen sink for treating the water that is used for drinking, cooking, and making ice.  This type of system is called a point-of-use device because it only treats the water at one point in the home.  The installation of this device is up to the homeowner.  

The reverse system is composed of a sediment filter, followed by a carbon filter, the reverse osmosis filter, and then a final carbon filter.  A picture of the installed system is shown below.  The RO system was donated for use by Lowe’s Home Improvement Warehouse in Simpsonville, SC, and sells for about $200. 

The RO system was quite effective in removing uranium. The average uranium concentration in the water of this home before treatment was 3,240 ug/L.  After treatment, the average concentration is 1.95 ug/L.  This is an overall removal of 99.9% of the uranium from the drinking water.  A graph of the data is presented below, along with a summary of the treatment data.   

Uranium Removal by the Reverse Osmosis System (average removal = 99.9%)

Reverse Osmosis Treatment for Uranium

Reverse Osmosis Treatment Data for Uranium

Uranium Concentration - Before Treatment, ug/L

Uranium Concentration - After Treatment, ug/L

72 hrs

3340

0

1 week

3630

2.3

2 weeks

3850

1.73

3 weeks

3610

2.85

1 month

3200

1.12

2 months

2900

1.71

4 months 2550 2.77
6 months 1880 2.07
    

       

 

 

 

 

 

 

 

 

 

 

 

 

Removal of radon in water by the RO system has been moderately effective, with an average removal of 97.2 %.  However, despite the relatively high efficiency, the amount of radon in water for this home prior to treatment is quite high, with an average concentration of 41,812 pCi/L.  After treatment, the average radon in water concentration was 1,012 pCi/L, which is above the proposed MCL of radon of 300 pCi/L.  The RO system alone cannot remove enough radon to achieve the proposed MCL, but it does remove enough radon to meet the alternate MCL proposed by EPA of 4,000 pCi/L,.  The alternate MCL has been proposed in order to encourage homeowners to test the air in their home for radon.  An additional carbon filter installed after the reverse osmosis system may further reduce the radon levels in water to an acceptable level.  A graph of the radon in water data is presented below, along with a summary of the treatment data.   

Radon Removal by the Reverse Osmosis System (average removal = 97.6%)

     

Reverse Osmosis Treatment Data for Radon

Reverse Osmosis Treatment Data for Radon

Radon Concentration - Before Treatment, pCi/L

Radon Concentration - After Treatment, pCi/L

72 hrs

30900

29.3

1 week

28500

2100

2 weeks

32000

1150

3 weeks

31700

1820

1 month

49800

1700

2 months

47500

282

4 months Field Sampling Error Field Sampling Error
6 months 10400 -26.4


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