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There are only 4 practical ways that we are aware of
to soften water:
- Traditional salt-based ion exchange water
softeners (sodium & potassium chloride).
- Deionisation systems. These systems use caustic
soda (sodium hydroxide), as a regenerate, and it is
not practical to use this hazardous material in a
residential application.
- Reverse osmosis. High quality water, but
expensive and maintenance intensive. Normally only
used in whole-house applications when no other
option is available, for instance, extremely high
water hardness, or in a remote island location when
only salt water is available.
- Distillation. This makes a very high quality
water, but normally not used in whole-house
applications, as it is very energy intensive. Used
commonly for high purity drinking water systems.
The solution to hard water
is either to filter the water by distillation or
reverse osmosis to
remove the calcium and magnesium, or to use a water
softener. Filtration would be extremely expensive to use
for all the water in a house, so a water softener is
usually a less costly solution.
The idea behind a water softener is simple. The
calcium and magnesium ions in the water are replaced
with sodium ions. Since sodium does not precipitate out
in pipes or react badly with soap, both of the problems
of hard water are eliminated. To do the ion replacement,
the water runs through a bed of small plastic beads or
through a chemical matrix called zeolite. The beads or
zeolite are covered with sodium ions. As the water flows
past the sodium ions, they swap places with the calcium
and magnesium ions. Eventually, the beads or zeolite
contain nothing but calcium and magnesium and no sodium,
and at this point they stop softening the water. It is
then time to regenerate the beads or zeolite.
Regeneration involves soaking the beads or zeolite in
a stream of sodium ions. Salt is sodium chloride, so the
water softener mixes up a very strong brine solution and
flushes it through the zeolite or beads (this is why you
load up a water softener with salt). The strong brine
displaces all of the calcium and magnesium that has
built up in the zeolite or beads and replaces it again
with sodium. The remaining brine plus all of the calcium
and magnesium is flushed out through a drain pipe.
Watermation Ltd can assess your water supply and
install a suitable water softening system in your
premises.
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