|Im investigating water treatment. I heard that a
few years ago that we were short on water,and
that they could make fresh drinking out of ocean
water. Im wondering what things does the ground
water have and ocean drinking water doesn't have?
|Question Date: 1999-01-25|
Ocean water has a lot of salt in it which gives it
a salty taste. Drinking a lot of it can make you
sick, though, so the salt has to be taken out.
Ground water has some salt in it but not enough to
make you sick. Your town probably doesn't have
enough ground water to for everyone to drink so
they need to purify ocean water.
Certain chemicals are
more strongly bonded to chemicals in soils.This is
because they have charges--a positive charge or a
negative charge in the soils and the chemicals.
Therefore, chemicals usually move very slowly.
Since there is water in the ground, this water
becomes contaminated. The contaminated water
helps certain chemicals to move about and
certainly some of which flows into the sea, but
since the sea is so large...the result is a
general "dilution of the pollution"--which seems
to be the solution. So it is not that it isn't in
the sea, but rather that it isn't in enough
concentration in the sea to do much harm. Though
over time this may change--specifically in
localized regions. This means if all the water
entering the sea in a specific location is heavily
polluted or over a long time the sea becomes
heavily polluted in one spot, then you will have
the same problem with your drinking water, if you
chose this place to build your desalinization
plant. Note: some chemicals are heavy or don't
breakdown very much under saline conditions and
some will be disperesed or will break down. Once
again it depends.
Living in Santa Barbara, we had a similar
situation (actually the whole state was in a
severe drought) where we were very low on drinking
water reserves. Since at that time Santa Barbara
did not receive "state water" - water redirected
from northern California to southern California
via the California aqueduct- we were desperate.
Guadalupe was in a very similar situation. In
both cases the decision was made to build
desalinization plants (de=remove, saline=salts)
which would take the salts out of ocean
and convert it into fresh drinking water. The
problem is desalinization of ocean water is very
difficult and thus expensive. So it is really a
last resort. Therefore, desalinization facilities
are only used in the most dire of straits, when
there is no other solution. The Santa Barbara
desalinization plant hasn't been used since around
1989-90 when the drought ended (and it began to
rain) because now our reserves fill up enough in
the winter and spring to supply the county with
enough drinking water for the rest of the year.
Basically, its just a lot easier and cheaper to
use rain water/ground water instead of ocean
I don't know for sure. That's a good question.
It probably depends on where you live. The salts
in the ocean come from the ground, either by
flowing groundwater or in rivers, so the things in
the water in the ground should be pretty much the
same as the things in the ocean, except that there
will be less of them. On the other hand, ocean
water is pretty much the same everywhere because
it gets mixed by waves and ocean currents, but
ground water will have things in it that have to
do with the rock it is in. So there could be more
of some things and less of others. Also, I don't
know how much gets filtered out in the making of
drinking water from ocean water. It's a good
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