Iron and manganese in ground water 6

[jocky]

Has anybody had any dealings with a company in San Francisco called 'World Construction Company'? I'm wanting information on their ground water filter media high contact oxidation membrane. Can anybody recommend it?
Thanks, Ross Douglas, New Zealand.

 

[semo]

What method of treatment are you using (greensand filtration, aeration/sedimentation/filtration)? This will have an affect on what chemicals you might want to use.

To answer your question, Chlorine has a Stoichemic dose of 0.63 for Fe and 1.29 for Mn. KMnO4 has a dose of 0.94 for Fe and 1.92 for Mn. These doses are the parts of Cl2/KMnO4 needed for 1 part of Fe/Mn.

If you use Cl2 for oxidation of Fe, you will need a total of (47*0.63) or 29.61 mg/l of Cl2. If KMnO4 is used to oxidize the Mn you will need (4*1.92) or 7.68 mg/l of KMnO4.

My experience has been that Mn is hard to treat; however, when the Fe/Mn ratio is 10:1 or better, the Mn co-precipitates out with the Fe on a relatively easy basis. I have not had iron levels as high as yours however.

Both will oxidize the metals; however, because of the higher cost for KMnO4, chlorine is more economical to use. It's drawback is the slow precipitation of the Mn. The KMnO4 has a higher oxidation rate (just a few minutes). Both may require pH adjustment dependent upon your water characteristics.

Cl2 will precipitate the Mn; but, at your high levels KMnO4 may be needed to make the plant smaller and less costly. I would plan for it as the costs involved are low (metering pump, storage tank, and mixer).