Water Crisis at ISS - Follow Up Question Water Recovery

Say, instead of boiling out the water to leave other 'stuff' (uric acid,
etc) behind wouldn't some type of freeze and/or centrifuge type
apparatus be more kind in the low tolerance environment?


TBerk

"T" wrote in message
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Say, instead of boiling out the water to leave other 'stuff' (uric acid,
etc) behind wouldn't some type of freeze and/or centrifuge type
apparatus be more kind in the low tolerance environment?

An alternative to boiling - a practical alternative - is to use reverse
osmosis (RO). It is used to make water that is biologically active (sea,
river, lake and even urine) into safe drinking water. Hand-held units are
available in most camping stores.


--
Alan Erskine
We can get people to the Moon in five years,
not the fifteen GWB proposes.
Give NASA a real challenge

Alan Erskine wrote:
An alternative to boiling - a practical alternative - is to use reverse
osmosis (RO). It is used to make water that is biologically active (sea,
river, lake and even urine) into safe drinking water. Hand-held units are
available in most camping stores.


These units end up using much electric power to generate the very high
pressures to cause osmosis to occur through the membrane, and also waste a lot
of water since you need to regularly clean/flush the untreated side of the
unit to remove the concentrated bad stuff that doesn't pass through the membrane.

These units work very well at sea to provide drinking water to
passengers/crews of smaller boats because there is plenty of water to flush
the units to remove the accumulating salt and other impurities reglarly.

It may turn out to still be the best solution for ISS. But it is far from
perfect in terms of recyling all of the water.

In terms of boiling urine, you'd have to contend with both the escaping gases
as well as any solid residue after the water has all evaporated. The later may
prove to be maintenance intensive at the station and problematic since they
solid residue woudln't fall to the bottom of the kettle, it could easily float
into the tubes that carry steam and gases to where the steam condensates and
gases are vented to space.