Question for Dr Tim and others

[heus]

This is the route I went...

http://mapletrader.com/community/sho...er-to-Flush-RO

Sean very interesting. How has that worked out for you? Do you feel it is removing all of the iron?

[heus]

Dr Tim do you feel these remove enough iron to do the end of the year wash and rinse? Also storage with preservative? Maybe even run two filters in line instead of one? My well water has a pretty high iron content judging by the stains it leaves at the faucet.

[DrTimPerkins]

Dr Tim do you feel these remove enough iron to do the end of the year wash and rinse?

They should be OK as long as you don't exceed the flow rate, pressure, and capacity of the cartridge. Putting two in series would provide an additional safety cushion. We use a deionizing system to produce pure water for our research. It is much more high tech than these, but basically the same process.

[jbuck]

Hi All,

Question about the specific chlorine concentration level allowed in a membrane wash/rinse solution. I have a source of municipal water that I'd rather use than draining my personal well at home. I'm going to test it before use of course, but just wanted to understand what other folks' experience has been when using treated water in their RO.

Several folks have commented on how chlorine will dissipate off a vented tank of water and my question is, after testing this water for chlorine ppm before and after storing it for use, what is the target level of chlorine? Can one expect the chlorine to be completely gone after a period of time vented to the atmosphere? Most inexpensive test kits take readings down to 0.5 - 1.0ppm so I hope that within that tolerance band, the solution would be adequate to use for membrane rinsing. Does the time required to vent increase with water volume or depth of container?

Thanks

[DrTimPerkins]

As usual...it depends. Is the water treated with chlorine or chloramine? Chlorine is fairly volatile, and will dissipate to very low levels after several days. More evaporation surface area is good, depth is not. Aeration or spraying is good for volatilization. Chloramine is considerably more stable, and doesn't volatilize off very well, which is why it is often used. Boiling will remove both chlorine and chloramine...10 minutes of boiling is typically sufficient. You should check the specs of your membranes though to see how sensitive they are to chlorine...or ask you dealer.

[johnallin]

Hello Dr. Tim.

I purchased some charcoal(?) filters from the Bucket RO guys at LEME. They said these would remove Chlorine from our municipal water, making it suitable for cleaning the membrane on my RO.
Is this what you difference in the http://mapletrader.com/community/sho...er-to-Flush-RO post? If so; they are readily available and may solve some start-up issues many are having...including me.

Thanks John

[DrTimPerkins]

If done properly, it works just fine.

[jbuck]

I called CDL to get more information on membrane washing procedures and things to watch out for. I learned that when membranes are sent back to CDL St. Albans for off-season washing, they run municipal water through them. The gentleman I spoke with was not concerned about the exposure to free chlorine or chloramine because as a percentage of the annual cumulative flow through a membrane, whatever normal small amount of these compounds might exist in municipal water does not pose a measurable threat to the membrane. He indicated that it would not be feasible for CDL to pre-treat all of their wash/rise water for a few hundred membranes each year. He went on to say that their process includes:

1. Rinse + caustic wash
2. Rinse + acidic wash and soak minimum 24 hours (with oxi-san or equivalent)
3. Rinse + caustic wash + rinse

Additionally, he said that the oscillating washing cycles of alkaline/acidic/alkaline is "good exercise" for the membrane because it helps keep the material elastic and operation performance at its best.

This information gave me a lot more confidence in my options for providing wash/rinse water at my sugarhouse.

[DrTimPerkins]

... was not concerned about the exposure to free chlorine or chloramine because as a percentage of the annual cumulative flow through a membrane, whatever normal small amount of these compounds might exist in municipal water does not pose a measurable threat to the membrane....

That's a bit surprising. Municipal water can contain up to 4ppm chlorine. Tolerance specs for RO membranes are often < 0.1 ppm for short-term exposure.

[bill m]

I have municipal water at my sugar house and use it for the first wash of the season. I check the chlorine level first and it is never above .1ppm . When I fill my tank I turn the water on slow with a fine mist nozzle to help dissipate any chlorine.