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Drinking Water
 Westfalia
Separator Environmental Systems supplies the following main products
For the following applications
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Water Works- Alum Sludge Dewatering
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Ground Water Sludge Dewatering
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River Water Sludge Dewatering
Every sixth inhabitant of this planet does not
have access to clean drinking water. In a few decades, this figure
will have risen to every fourth person. Researchers are depicting
horror scenes of wars fought over drinking water.
Drinking water is obtained either from surface water, e.g. rivers
and lakes, or from ground water.
Average world-wide per capita water consumption is currently
estimated at 150 m3 per year. Of this figure, only between one
and three percent are actually used for consumption.
In the EU countries, 64% of drinking water is currently obtained
from surface water, and 36% is obtained from ground water. When
drinking water is obtained from surface water, the resultant sludge
has to be processed by means of a decanter.
This need to process water into drinking water will in future
become increasingly important as the population expands and as
environmental pollution becomes more and more evident.
Surface Water as a Source of Raw Water
Surface water is polluted by nature as well as by mankind. The
main sources of impurity are as follows:
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humus, decomposed vegetable components which colour water
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mineral particles which result in cloudy water.
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Organic impurities of natural or human origin
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Bacteria and viruses.
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Decanter type CD 305 for the treatment of drinking water |
Chemical Treatment of Surface Water
Chemical precipitation is the main method of treating these impurities.
The typical process stages for moderately contaminated raw water
are as follows:
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Removal of small pebbles.
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Pre-alkalisation in order to adjust the pH value to an optimum
level for subsequent precipitation process.
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Chemical precipitation with coagulators such as aluminium
sulphate, polyaluminium sulphates or iron chloride. The same
process stage comprises flocculation using polyaluminium chlorides
or polyelecro-lytes.
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Separation by way of sedimentation (e.g. plate-type separators)
or flotation.
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Filtration in a quick sand filter. Back-flushing of the quick
sand filter releases sludge which is forwarded to the sludge
dewatering proc-ess.
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Subsequent alkalisation and chlorination.
The purpose of these steps is to protect pipework and to prevent
the growth of bacteria.
Additional Measures
These treatments can vary tremendously depending on the particular
area of application in view of the very different compositions
of raw water.
The above-mentioned process scheme is generally used for highly
con-taminated raw water featuring more than 20 to 40 g/m3 dissolved
solids. Filtration without previous precipitation is sufficient
for water with lower levels of contamination.
A slow sand filter is an alternative to the chlorination process;
in a slow sand filter, all remaining organic substances are broken
down in an active biological layer.
After these process stages, the water can additionally be treated
with active carbon in order to remove certain taste and odour
problems. This procedure can be carried out by way of adding powder-form
carbon before the precipitation process or by means of a filter
filled with granulated
carbon.
Westfalia Separator decanters have been designed for a high clarification
performance and maximum solid dewatering. Examples of major requirements
in this respect are a high bowl speed and a high scroll torque
in conjunc-tion with a differential speed regulating facility
which operates as a function of the solids load.
When combined with a closed installation, the closed design prevents
any escape of aerosols and thus protects the health of the operating
personnel and the environment.
Increased wear protection can be provided to the scroll vanes,
solid discharge holes, solid catching chamber and the product
inlet area in the scroll for use in industrial and local authority
applications.
Technology for a better quality of life.
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