Method of removing salts of the alkali earth metal group from water

A method of removing salts of the alkali earth metal group from water is provided wherein water is supplied at a controlled flow to a pair of serially connected five-micron prefilters which remove contaminants and reduce the flow rate. The effluent is then passed through at least twelve parallel connected activated charcoal filter units where the flow is reduced to approximately 0.5 g.p.m. allowing additional time for the alkali salt to be adsorbed in the charcoal.

This invention relates to a method for removing salts of the alkali earth 
metal group from water. In general potable water is extracted either from 
surface supply, such as lakes and rivers or from ground water. Many of the 
public water supplies are taken from ground water which generally is in 
place for a long time. For this reason, contaminants can remain present at 
high concentrations long after entering the ground water. A still further 
characteristic of ground water is that this liquid is actually contained 
within rock and possibly sediments, and therefore receives considerable 
filtration. This filtration effectively eliminates biological hazards, but 
it is far less successful at stopping toxic chemicals. 
Methods are availabe for removing many pollutants from drinking water, for 
example, aeration, granulated activated carbon, and reverse osmosis, are 
all techniques currently recognized by the EPA. To be effective against 
some of the chemicals currently listed as being either toxic or 
carcinogenic it has been discovered that properly used, high-quality 
treatment systems offer some protection against toxic chemicals in 
drinking water; but to be effective against even the treatable pollutants, 
the treatment system must not be overloaded. For example, it has been 
discovered that granulated activated carbon requires at least a half hour 
of contact to be effective against some chemicals. 
It is an object of the present invention to provide a new and improved 
method for treating potable water that is safe and reduces the presence of 
alkali earth metals. 
A secondary object is to provide a more effective, efficient and cost 
effective method without the need for expensive capital equipment for the 
user. 
According to the present invention, I provide a method of removing salts of 
the alkali earth metal group by reducing the flow rate into a filter bed 
and inserting at least two five-micron filters ahead of the main filter 
bed that is made up of granulated activated carbon.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
In proceeding with the invention, reference should be had to the 
accompanying drawing which illustrates a preferred arrangement. The first 
step in proceeding with the invention is to reduce the flow rate of the 
water and utilize an inlet pipe 10 no grant than a half inch in diameter. 
When this is done, the maximum flow rate through a half-inch pipe at 75 
lbs. psi will be on the order of 7.5 gallons per minute. The water is then 
introduced into a water filter housing 12 which contains a five-micron 
cartridge 14. The cartridge will be of conventional white cellulose 
cartridge designed for cold water service; and its insertion into the line 
will now reduce the flow rate on the discharge piping 16 which will also 
be preferably of a half-inch size, to something on the order of four to 
five gallons per minute. In many cases it is desirable to insert a second 
pre-filter as seen by the housing 20 which will contain a five-micron 
cartridge 22 that will again reduce the flow rate and remove additional 
particles such as solid particles that may be characterized as sand, silt, 
dirt and rust, for example. The flow rate now at the outlet piping 24 has 
now been reduced to approximately three gallons per minute, and this is 
fed into a large filter casing diagramatically designated 30, into which 
are located a plurality of parallel connected five-micron cellulose 
filters 32, located just ahead of granulated activated carbon cartridges 
34. The five-micron cartridge 32 and the charcoal cartridge 34 may be 
combined in a single cartridge for ease in installation. 
In its preferred form within the casing 30 there should be located at least 
twelve charcoal and five-micron pre-filters, it being recognized that 
purely by way of illustration, only five are shown. By utilizing this 
quantity of units, the flow rate at the output pipe 40 has been 
effectively slowed down to approximately 0.5 gallons per minute, which 
guarantees longer contact of the water with the granulated activated 
carbon, which has been labeled "activated charcoal" in the drawing. For 
convenience sake, the container 30 will also be provided with a drain 42 
so that any precipitated contaminants can be drawn off from time to time 
when actual replacement of the complete cartridges therein is necessary. 
The granular activated charcoal used in the cartridges 34 is generally 
processed in a multiple hearth furnace at a temperature of 1750.degree. 
F., into which steam is introduced so that the organic impurities are 
oxidized and devolatilized. This process creates an enormous surface area 
that is produced by the many cracks and crevices so that the charcoal 
looks somewhat like a natural sponge. This yields a large surface area 
which atracts and traps the contaminants in the water as the water is 
passed therethrough. As the water flows through the charcoal, chemicals 
are adsorbed by the activated charcoal. In addition, it is believed that 
the salts of the alkali earth metals are precipitated, since it is 
believed that by slowing the water flow through the micron filtering, a 
loss kinetic energy attracts the cations of, for example, sodium, and the 
anions of chloride and are rejoined to form a larger mass that 
precipitates out of the fluid. 
A number of tests have been conducted that show conclusively that indeed 
the alkali earth metal cations are significantly reduced, and the data is 
shown herein, Table I indicating the reduction of the alkali earth metals 
and the cation chloride in analyses that were done as indicated in the 
table. It is significant to note that after the units have been installed 
for a short period of time, the data shows very significant reduction in 
the sodium level which causes a bad taste in the water. 
Table II is a test taken at another location with different levels of 
sodium in a municipal water supply, still indicating significant 
reductions after an installed period of three months. 
Table III is a further indication of another location where tests were made 
with one or two pre-filters of the type indicated as 12 and 20 in the 
drawings where a further significant reduction was attained with two 
pre-filters, only sodium and chloride having been tested. 
TABLE I 
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WATER WATER 
WATER IN OUT PPM OUT PPM 
PPM (after 3 months) 
(after 6 months) 
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Calcium 16 15.5 11.0 
Magnesium 
4.5 5.0 3.0 
Sodium 75.0 32.5 30.0 
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TABLE II 
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WATER IN WATER OUT WATER OUT PPM 
PPM PPM (after 3 months) 
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Sodium 9.5 9.0 4.4 
Chloride 
15.0 15.0 9.6 
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TABLE III 
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PPM ONE PPM 
RAW IN PPM PREFILTER TWO PREFILTERS 
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Sodium 40.0 16.0 7.15 
Chloride 
75.0 32.5 23.2 
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