Fri 26 Dec, 2008 07:45 am
I was advised recently that a GreensandPlus media just backwashes to remove iron or sulfur without potassium permanganate, or chlorine or anything else. Please becareful if you receive this advise, there is an error in this approach.

Andy Christensen, CWS-II
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farmerman
 
  2  
Fri 26 Dec, 2008 08:15 am
@Andy CWS,
I agree, greensand is an ion exchange media not a simple adsorbant. To adsorb one ion (like Mn or Fe) it releases an ion from the glauconite matrix. In order to reeverse this, you must add some kind of resorbant ion mix. Usually its KMnO4, but it could also be something like a specially formulated EDTA base.

There is no free lunch even in surface reactions
Andy CWS
 
  1  
Fri 26 Dec, 2008 09:24 am
@farmerman,
Farmerman,

Thanks for the reply. I thought greensand was a catalyst type media rather than an ion exchange like a softener.

I was given advice by a member here that this nwere version (GreensandPlus) needs to only backwash. I find that a very strange thing to say as the media removes not sediment as its purpose (this backwashing only can work) but removes iron and sulfur.

Therefore "just backwashing" wouldn't seem to work as the backwashing water (not from a twin tank system) contains the same problem water and the water used for treatment.

Thanks again,
Andy Christensen, CWS-II
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farmerman
 
  2  
Fri 26 Dec, 2008 11:17 am
@Andy CWS,
Glauconite is the group mineral name that is contained in "Greensand". Its nomenclature was most recenly defined in the API Handbook of GEology , (which got its insert from Bailey, S. W. 1980, THE HANDBOOK OF CLAY AND CLAY MINERALS).

glauconite sands are mined in Delaware and NEw Jersey and in the coastal plain of MAssachussetts and Maine and New Hampshire. Chemical companies used to use glauconite as the model fro developing new ion exchange salts and resins . Its still used extensively in packing towers for municipal water supplies. (Usually they have 2 towers and they dont backwash, they rebbed the towers one at a time while they watch for breakthrough for iron and manganese. They will take the old greensand back and extract the exchanged ions.(They used to use it for packed beds to collect gold and platinum in water out west. The greensand was mixed with Rohm and Haas ion exchange resins.

Its neat stuff
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H2O MAN
 
  -2  
Sat 27 Dec, 2008 10:33 am


I'm getting excellent results with FILOX.
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MatinJohn
 
  0  
Mon 29 Oct, 2012 10:43 pm
@Andy CWS,
Hello Community,

Greensandplus filters use a specially formulated filter media made from a naturally mined form of glauconite greensand. The greensand filter media has a special coating of manganese oxide, which oxidizes iron, manganese and iron in water, upon contact with the filter media. Greensand filters require a type of purple powder, potassium permanganate to regenerate and clean the greensand filter media. Potassium permanganate is a powerful oxidizer and, similar to chlorine, can cause skin irritation or burns if direct contact were to occur. But, no permanganate is added to the filtered water. The permanganate is only used to backwash and clean the greensand filter media. A special rinse cycle makes sure the filter bed is free of any permanganate residual.

Best Regards,
Matin John
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H2O MAN
 
  -1  
Tue 30 Oct, 2012 07:19 am


I have done some research and found that the Greensand Plus
doesn't use the 'purple' stuff, it uses a type of chlorine tablet.
I hope this is true because I hate using Potassium permanganate.

Quote:
GreensandPlus is a purple-black filter media used for removing soluble iron, manganese, hydrogen sulfide, arsenic and radium from well water supplies.

Like it's sister product manganese greensand, the substrate media has a manganese dioxide coated surface that acts as a catalyst in the oxidation-reduction reaction of iron and manganese. The difference between GreensandPlus and manganese greensand is in the substrate that forms the core of the media and the method by which the manganese dioxide coating is attached to that substrate. Greensand Plus has a silica sand core and the coating is fused to it while Manganese Greensand has a glauconite core and the coating is ionically bound to it.

The silica sand core of GreensandPlus allows it to better withstand operating conditions in waters that are low in silica and TDS and hardness. Thus, if you currently are using manganese greensand and are feeding sodium aluminate, you will likely be able to eliminate the aluminate feed by switching to GreensandPlus. Also, GreensandPlus can withstand higher operating temperatures and higher differential pressures than can manganese greensand. The higher differential pressure may allow for a longer run length, but, if nothing else, allows for more operational margin of error.

Along with the added benefits, comes the fact that GreensandPlus is an exact replacement for manganese greensand. It can be used in CR and IR applications and requires no changes in backwash rate or times or chemical feeds. Greensand has received the WQA Gold Seal Certification for compliance with NSF/ANSI 61. It is available in easy-to-handle 1/2 cubic foot bags or 1 metric ton (2205 lbs) super sacks.
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