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Subject: Water purification

Water purification

From: Jim Druzik <jdruzik>
Date: Thursday, November 17, 1994
Cal Hermann is a chemist working in the Pulp and Paper Laboratory,
Richmond Field Station, University of California.  Hermann is formerly
of the Water Technology Center and has worked on water treatments.  As a
result of submissions to the distribution by both Geoffrey Brown and
myself, Hermann has added several valuable comments.

We all agree that distilled water has limitations.  CH and GB also agree
that deionizing cartridges are more convenient but CH cautions that,
"They become contaminated  by degradation products if not used for 6
month or so (in that case: flush out 10 liters or so)."

GB remarked about high installation costs for reverse osmosis but CH
comments that costs are associated with the quantities of water needed.
One may be talking about hundreds of dollars for maintenance and not
thousands or more.    My feeling is that If the proposed conservation
laboratory is unable to estimate its water demand the tendency will be
to overbuild.  This is difficult because the number of people and space
requirements will influence the decision.  So will the treatment
philosophy of the lab and the amount of time spent on phase box
construction or other non-washing activities.  This might be best
handled by asking other labs in order to set the range of requirements.

Cal Hermann further noted that many deionizers have test lights on the
top and Millipore (TM) and some other reverse osmosis systems come with
a meter built-in.  As a another option small conductivity meters should
be adequate to check the reliability of the installation.  To address
the problem of wasted water from RO, it is very possible to divert it
for non-critical purposes.

Concerning paper pH, if the main function is to spot unstable acidic
paper, the narrow-range paper indicator strips could be adequate.

Jim Druzik

                  Conservation DistList Instance 8:38
                 Distributed: Sunday, November 20, 1994
                        Message Id: cdl-8-38-008
Received on Thursday, 17 November, 1994

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