Water purification systems-Which is best?

[Curt Ashendel]

On Wed, 22 Jun 94 16:36:39 CDT, 
Elmer M. Price, Ph.D.  <DCRCEP at mizzou1.missouri.edu> wrote:
>My lab is in the market for a water purification system.  Our applications
>are molecular biology, protein purification and cell culture.  So far, we
>have narrowed our choices to either the Millipore MilliQ UF Plus system
>or the Barnstead Bioresearch Nanopure system.
>     Dear netters, what are your opinions regarding these items.  If you have
>either system, are you happy with it?  Are there other vendors I should explore
>(such as Solution Consultants)?  Other comments?

I just set up a new lab last year.  The salespeople descended on me...
I chose the Barnstead still.  Why?  My reasons:

#1. I don't have to pay for electricity, but I do have to pay for cartidges 
and UF membrane units.  Estimated cost per year for a MilliQ UF system:  
US$700.  Cost per year for Barnstead <US$100.

#2. I have mostly students in my lab (udergrad, grad, etc.)  They must 
be  trained in the proper use of the water system.  The MilliQ systems must 
be cycled before using them or the water is no good.  If the supply water 
is bad (or even not too good), the cartridges and/or membrane go bad before 
the timer on the device indicates that new ones are needed.  Either way, 
the water still comes out of the hose and it stills looks good, so you only 
find out otherwise when your experiments don't work and you have eliminated 
all the other possible explanations [some people blame the water first ;-)] 
With a still, as long as the supply water is good quality (RO + mixed bed 
ion removal), if the condensate comes across, then the water is good.  NO 
QC is needed.  This reduces training and chances of screwing up by 
undertrained individuals.  In other words, stills are more robust than 
filtration-based systems.

#3.  I have used water stills for nearly 20 years in scientific research, 
and they work more consistently than the filtration based systems, IMHO.  

For others there may be other reasons we did not need to consider (heat 
generation and air conditioning, for instance).  My reasons may not be 
significnat in some situations.  Also, deilvery rate may be important 
unless storage is used.  Storage has risks, although the autofilling 
storage system Barnstead offers is directly coupled to the still and the 
water in it stays sterile (or nearly so).  We have never needed to clean 
one of these types of storage containers.


Curt Ashendel
Purdue University
West Lafayette, IN
ashendel at aclcb.purdue.edu