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PRESIDENTIAL
PALACE BAGDAD
IRAQ |
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How Does It Work? Diffusion is the movement of molecules from a region of higher concentration to a region of lower concentration. Osmosis is a special case of diffusion in which the molecules are water and the concentration gradient occurs across a semi permeable membrane. The semi permeable membrane allows the passage of water, but not ions (e.g., Na+, Ca2+, Cl-) or larger molecules (e.g., glucose, urea, bacteria). Diffusion and osmosis are thermodynamically favorable and will continue until equilibrium is reached. Osmosis can be slowed, stopped, or even reversed if sufficient pressure is applied to the membrane from the 'concentrated' side of the membrane. |
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BAGDAD - NEW
INTERNATIONAL
AIRPORT - EEC
RO-2x550 m3 per
day Delivery
March 2008 |
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The EEC
Desal
Reverse
Osmosis Desalinators utilizes
the latest in reverse osmosis
membrane technology to convert
Seawater, Brackish water, or non–potable water
into drinking water. All plants are customized to clients specific need to secure reliable equipment and safe drinking water.
Always consider Energy
recovery systems on larger
RO plants.
Some additional basic
information below. |
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Every seawater RO
application is unique and
very site specific. What may
be the optimum solution for
one plant will not
necessarily be the optimum
solution for other plant.
Variables include salinity,
temperature, pretreatment
requirements and finished
water quality. Some
parameters, such as
materials, will be constant.
Seawater is, after all,
seawater. Regardless of
location, the predominant
component of the seawater is
sodium chloride, which
experience has taught us
requires materials that
resist attack by the
chloride ion.
Pretreatment.Perhaps
the most critical factor in
the design of a successful
seawater RO facility is
acquisition and pretreatment
of the source water. There
are two techniques for
acquiring the raw water, and
for a variety of reasons,
both are probably not
applicable to all cases.
Seawater, of course, is
predominately a coastal
phenomenon and as such
occurs alongside beaches,
mudflats, swamps, cliffs and
other assorted geologic
features.
In most
cases, it is unlikely that
sufficient seawater for a
large plant can be acquired
from one of the many options
commonly classified as
“beach wells.” However, if
the proposed plant capacity
is sufficiently small (<5
mgd), extracting the
seawater feed from a beach
well or through a
constructed infiltration
gallery is preferable to
open intake because the
pretreatment challenges will
be less demanding.
For large
plants, surface water intake
facilities are required.
These are similar to intakes
used for coastal power plant
cooling water.
Assuming the
feed source is an open
seawater intake, the
proposed pretreatment scheme
must consider the following:
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Control of plugging and
colloidal fouling;
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Control of organic
fouling; and
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Control of biological
activity and fouling.
Traditionally, seawater
pretreatment has consisted
of flocculation and
coagulation with a ferric
salt, sometimes applied in
conjunction with a polymer,
sedimentation and
filtration. Depending upon
the circumstances, a
continuous chlorination and
dechlorination procedure
sometimes is employed.
Intermittent chlorination
and dechlorination is also
practiced. Filtration
has typically been practiced
as a two-stage process using
dual or multi-media beds.
Traditionally, the first
filter operates at a
relatively low loading rate
of 3 to 5 gpm/ft2, while the
polishing filter operates at
a higher 5 to 7 gpm/ft2.
When sizing the filtration
equipment, capacity for the
production of backwash water
must be included. |
