Re: [Killietalk] pelletized peat moss---a new medium?

[Charles Harrison <charles at inkmkr_com>]

Bruce,
I wonder how you are determining the Calcium in the water. Calcium 
referring to the Hardness? If you are using AA or ICP, the Calcium 
should still be there in the water, Brown water that is.

Using local tap water (250 ppm Ca) filtered through peat Moss, I have 
determined Calcium concentrations in the brown water you observe and 
found an EDTA titration indicates a major drop in measurable Calcium. 
I have then filtered the dark Water through Activated Charcoal to 
remove the color completely and found the calcium to return to the 
same level by EDTA titration. The dark compounds like the Charcoal 
better than they do the metal ions. Now we should start talking about 
affinity coefficients, pKa's and a relationship between the various 
components, pH and the Peat. That sounds like a David Koran question. 
I believe he did his Ph D on something about Peat Mosses - Yes?
anyway
You didn't say what the pH of the water pre Peat treatment was - ? 
could it be acidic or near neutral?

Charles Harrison



At 3:13 PM -0500 1/2/06, "Bruce J. Turner, Dept. Biological Sciences, 
VPISU, Blacksburg wrote:
>Some weeks ago, while purusing the local department stores for out-of-season
>bargains, I came upon a product which I had not seen before, 
>pelletized peat moss.  I am not talking about Jiffy pellets here, 
>but a product that looks like dark brown coarse gravel.  The 
>manufacturer, a Canadian firm, states that these pellets are 
>prepared only from pure Canada sphagnum peat moss, and they 
>represent about a threefold volume contraction from the original 
>peat.  I have been experimenting with various types of peat moss to 
>soften my well water, so I decideed to try these as well, figuring 
>that the compressed volume would make them more valuable as a 
>filtration medium, even if they subsequently swelled in the water. 
>I have now tried them twice, in two different replicate experiments, 
>and have found the following:
>
>1.  They have no measurable effect on the pH of my well water, even 
>when that water is turned very dark brown by the filtration through 
>the peat pellets.
>
>2.  They rapidly remove Ca hardness---more effectively than plain 
>peat moss even if the compression ratio is taken into account.  If 
>one doesn't care about dark brown water, this is the most efficient 
>peat-based medium I have ever used for water softening.
>
>3.  They have only a slight effect on CO3 hardness!  I found this very
>surprising, but have now repeated the observation.  I start with a 
>KH of 16, and end with a KH of 14 - 16.  In my hands, ordinary peat 
>moss, including stuff labeled as "Canadian sphagnum peat moss" 
>reduces KH and GH in rough proportion.  I have never seen any agent 
>do this before, and am puzzled about the chemistry that might be 
>involved. (I might add parenthetically that no one seems to know 
>exactly how/why peat moss softens warter---is it an ion exchange 
>effect, differential ab(d)sorbtion of divalent ions, or what...).
>
>Im thinking that if onecould deal withthe dark brown water, these pellets
>might be a good thing to use for filtration of troublesome water, 
>for the KH provides buffering power, and that could be quite 
>valuable in soft
>water.I would be interested in hearing from anyone who has used 
>these pellets and/or
>knows anything about them...

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