Used KDF85 Silver Color

[themitch]

Made a custom pre-filter for my RO unit I think about 3 or 4 months ago. Pulled it out to look at it tonight. First thing that I noticed is that it channeled. Design fault, but oh well.


It was interesting to see the material turn silver (zinc). Looks like the copper is being used up. Looking for what others have for thoughts about. I am looking to further improve the overall water in the house, not just the RO filter now.

A few notes, had a water test a year and a half ago. Showed Sodium at 150mg/l, TDS at 375, Alkalinity at 270 as CaCO3, pH at 8.46, and Langlier -0.224.

Any time I do work on the copper plumbing, or disturb it for any reason, there is black water that comes out later.

At this point, anyone have any ideas as to what would cause this?

 

[ditttohead]

KDF used as a pre-filter to an RO will do that, it is normal due to mis-application. For KDF to work well, it needs to be run in a downflow configuration with an intermittent backwashing. The filter is approximately 2.75" diameter, so a loose fill KDF 85 should be run at 1 gpm, or 25 GPM per Sq Ft. Most filter configurations are upflow, but the RO only draws about .1 GPMso the media is basically just sitting there. KDF in a filter like this will cake up sometimes and channel like yours has. There are some unique options to this design, but that is for a later date.

This is really going to be a long post. I will simplify it unless you would like more information, but in general, KDF is an amazing media that works extremely well for many applications when applied correctly. I have a 30+ pound system that feed my whole house and have had it for over 15 years. As a pre-filter to an RO, it can work, but this problem that has occurred to your filter is not uncommon.

 

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[themitch]

Cant say that I am really looking for it to be useful, I am using it as an experiment and to play around with what water I have and what can be done to improve it. Looking to see why it turned silver, and when rinsed out in a bucket, turned the water black. Its the corrosion product that produces the black water is what I am most curious about. With the well water not showing Manganese. There is a smell of H2S, still need to quantify the amount. Now that we have the RO for drinking water, which works perfectly, I am looking to make the other water in the house more "user friendly." Showers do smell like sulfur, and when the indirect hot water heater is flushed, it produces a ton of black sediment in the bottom that takes many flushes to get to a reasonably low amount. There is a slime bacteria in the well that has been a continuous source of trouble. Iron was N/D in the water test, and Magnesium was just 1.79 mg/L.

Reading up on a USGS report, the local formations do have Sodium Chloride at times. Thinking about getting a test done tomorrow to see what the water looks like during the dry season, not spring time. Again, this is just one big experiment for me in order to play with the water and understand what is causing the problems. Would pull the pump and string in order to send a borehole camera down the well if I had the time to see what the formations look like.

 

[ditttohead]

Typical redox reaction of hydrogen sulfide with KDF 85 process media Cu/ZN° + H S → CuS + 2H°

http://media.wix.com/ugd/a3c37f_da08e8a793084df692f258227fdc56e9.pdf

I would look at the H2S, bacterial issues first. KDF can control bacteria but... Lets see the water test report before we make any claims. I would recommend a simple chlorine injector/contact tank GAC tank to get rid of any bacteria prior to the water getting to your house.

 

[themitch]

Last years test.

No e-coli / total chloroform test was completed.

Was looking into the feasibility of using H2O2. Any experience with using Neutra Sul?

 

[ditttohead]

Hydrogen peroxide is fine, most use chlorine since it is highly effective, cheap, and readily available.