Re: [APD] R/O Biofilms

[Rob Smith <smithrm24 at gmail_com>]

I saw this once on the faucet from my undersink filters (ion exchange +
carbon).  What I saw was like little black flecks of paper, which I too
suspect was a biofilm, probably mold.  Servicing the unit I never noticed
any buildup in the unit anywhere so I think it was coming from the very end
of the faucet--after it drips dry, mold spores have easy access.  I only
ever saw this for a few days about a year ago and did nothing about it.  I
reasoned that the abrasion caused by the cleaning process could well make it
worse...

In my lab I use a sophisticated filtration system for my water that includes
a UV chamber for decomposing organic carbon.  This process certainly results
in the destruction of most microorganisms as well.  In spite of that, the
final piece of this filtration system is a 0.45 micron paper filter which
the manufacturer recommends be replaced every six months if the unit is used
often and every three months if it is not.  The reason for this
non-intuitive schedule is that, if left in standing water, there is
microbial growth inside the filter (and even inside the large filter
cartridges according to the manufacturer).  So the microbes are assumed to
be everywhere and even on this $12,000 purification system with UV
sterilization one assumes that they will eventually grow.  This seems
obvious since the systems are user assembled and certainly not sterile.

If the faucets you are referring to are the common type found on water
coolers then I think you can just unscrew them and put on a new one with
teflon tape.  They look pretty cheap but I'm not sure.  If it's a metal
faucet head like mine, I suspect it is impossible to prevent the buildup of
film on the air-exposed parts of the pipe.

My advice is, drink up!

Rob Smith


On 11/25/05, Jerry Baker <jerry at bakerweb_biz> wrote:
>
> I noticed while pulling a glass of water from my R/O unit tonight that
> there were little greyish floaty things in it. Upon further
> experimentation I discovered that when the faucet is turned on and off
> (to create a jarring movement of water), some stuff appears in the water
> that appears to be a biofilm of some sort. It doesn't appear in the
> glass if I turn the water on and then place the glass into the stream
> and remove it before turning off the faucet. Does anyone know how to
> stop this buildup from occuring, or at least how to dislodge it
> relatively easily?
>
> --
> Jerry Baker
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> Aquatic-Plants at actwin_com
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