Water desalinization process

A process for the desalinization of sea water which includes a barrier buried to a depth below the low tide water level in a sandy beach, and a collector vault or well buried in the beach behind the barrier, the well having an opening in its side for receiving water passing through the barrier. The barrier is filled with selected filter materials, and the sand in the area between the barrier and the well is treated with a selected material. The barrier extends through a water-permeable layer of crushed or fossilized shells naturally occurring beneath the sandy beach. The well opening is positioned within this shell layer. After a period of pumping, desalinated water will appear in the well and may be pumped out of the well. Whenever the water in the well is pumped below a particular level, a new supply of desalinated water will flow in through the opening in its side from the barrier.

BACKGROUND OF THE INVENTION 
The present invention relates generally to a process and apparatus for the 
desalinization of sea water and, more particularly, to such a process and 
apparatus which is simple and can produce large quantities of usable 
desalinated water at low cost. 
The term "sea water" as used herein is intended to refer to ocean water, 
and the like, having a sufficiently high total dissolved solid content so 
that the water is unusable for agricultural purposes. The term 
"desalinated water" used herein is intended to refer to water in which the 
total dissolved solids are reduced to a level sufficient to render the 
water at least suitable for irrigation purposes. 
U.S. Pat. No. 4,122,012, the disclosure of which is incorporated herein by 
reference, discloses a sea water desalinization system which includes a 
barrier buried to a depth below the low tide water level in a sandy beach, 
and a collector vault or well buried in the beach behind the barrier, the 
vault having an opening in its side for receiving water passing through 
the barrier. The barrier is filled with selected filter materials and the 
sand in the area between the barrier and the well is treated with a 
selected material, such as the sap of the guayule plant. After a period of 
pumping, it is stated that desalinated water will appear in the well and 
may be pumped out of it. 
While the system of U.S. Pat. No. 4,122,012 may produce some desalinated 
water, it cannot as a practical matter produce such water in significant 
or large quantities because the sand in most areas is not sufficiently 
porous or water-permeable to allow an adequate flow therethrough of water 
to the barrier and to the well. It is stated in this patent that, should 
the sand be very small and dense to retard water flow, it may be replaced 
with small size gravel to increase the water flow. The replacement of the 
sand with gravel, however, is both time-consuming and expensive. 
A need has arisen, therefore for such a water desalinization system which 
can utilize the existing materials in the beach without requiring the 
removal or replacement of same. The process and apparatus of the present 
invention fills this need. 
SUMMARY OF THE INVENTION 
The present invention utilizes apparatus similar to that disclosed in U.S. 
Pat. No. 4,122,012. It has been discovered, however, that if the barrier 
is positioned in a layer of crushed or fossilized shells naturally 
occurring beneath the sand in many beach areas particularly along the 
western shore of North America, there is sufficient water flow through the 
shell layer to produce large quantities of desalinated water without 
having to replace the sand with gravel or other materials. The opening in 
the well is also positioned in the shell layer to receive water flowing 
therethrough from the barrier. The sap or other material applied to the 
sand between the barrier and the well penetrates the shell layer to 
further aid in the removal of dissolved solids from the water passing 
through the shell layer. 
The system of the present invention has general utility in that it enables 
desalinated water to be produced in any desired quantity at negligible 
cost. The system is advantageous in that, apart from pumps, it does not 
entail any moving parts; nor does it require the introduction of heat, 
pressure or electricity from external power sources. In addition, the 
system of the invention has the capability of operating over prolonged 
periods of time without any noticeable deterioration of its components, 
and without the need for any substantial maintenance or servicing 
operations. In addition, the system of the invention has an advantage in 
that it utilizes relatively inexpensive and readily available materials in 
accomplishing its desired results. 
Although the theoretical principles upon which the operation of the system 
of the invention is predicated are not completely understood, it is 
believed that the filter materials contained in the barrier which, in 
accordance with the concepts of the invention, are embedded in the sand 
and shell layer of a beach, set up an ion-exchange reaction in the saline 
or brackish solution passing through the barrier, and this ion-exchange 
reaction causes a desalinated water separation, with the lighter 
desalinated water flowing above the heavier brine or brackish solution 
through the shell layer and into the opening in the well which is also 
imbedded in the shell layer. The desalinated water passes through the 
opening in the side of the well and into its interior, whereas the heavier 
brine solution is dispersed in the sand under the barrier and the well or 
may be pumped to waste through an appropriate drainage system installed 
below the level of the barrier and the well opening. 
Also, the sap of the Amate tree, family of the Ficus plants, is placed in 
the sand between the barrier and the well, and penetrates into the shell 
layer. This sap reacts with residual compounds in the sea or brackish 
water after passing through the barrier to cause such heavier materials to 
gravitate down into the brine solution underlying the upper layer of 
desalinated water. The only maintenance required in the system is to add 
additional sap to the area from time to time, depending on the amount of 
water that is passed through the system. In the event water quality should 
decrease, the addition of Amate sap to the filter materials in the barrier 
may be effected to reinforce the desalinating performance of the system.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
As shown in the drawing, a barrier 10 is embedded in a sandy beach 12 
between an adjacent body of salt water and a well or vault 14. The well 14 
is also embedded in the sand of the beach, and is displaced from the 
barrier 10 so as to provide an area "A" between the front side of the well 
and the barrier. An opening 16 is provided in the front side of the well, 
which opening may be covered with an appropriate screen to keep the 
surrounding materials out of the well. 
In accordance wth the principles of the present invention, the bottom 
portion of the barrier 10 is embedded in and extends through a layer 18 of 
water permeable, crushed or fossilized shells naturally occurring in the 
beach area about two feet beneath the upper surface of the sand 12. Also, 
the well opening 16 is located within the shell layer 18 so as to receive 
water flowing therethrough from the barrier 10. Normally, such shell 
layers are about one foot thick, occur at zero tide level and contact the 
sea underwater at a point where the force of the waves breaking on the 
beach drives or pumps sea water inland through the shell layer which may 
extend inland from zero tide level approximately 100 meters or more. As an 
illustrative example, the barrier 10 should be located at least 50 meters 
inland from zero tide level to take advantage of the filtering action of 
the shell layer 18 on the sea water passing therethrough. If the length of 
the shell layer is 100 meters, for example, it is preferable that the 
barrier 10 be located about 90 meters inland and the well 14 be located 
inland from the barrier approximately 10 meters. 
The barrier 10 is embedded at a selected depth under the sand of the beach, 
so that at low tide and high tide, all water flowing under the sand to the 
well opening 16, flows through the barrier. The well 14 preferably is 
displaced upwardly with respect to the barrier so that only the upper 
layer of water in the shell layer passing through the barrier passes 
through the opening 16 with the lower layer of water flowing under the 
well. A pump 20 is provided for pumping desalinated water out of the well 
through an inlet pipe 22 and an outlet pipe 24. Water velocity entering 
the well opening 16 is controlled by the rate of the pump 20. 
As described above, selected materials aee included in the barrier 10 which 
react with the salt water to help form a layer of desalinated water over a 
layer of brine solution. Whenever the level of water in the well 14 is 
pumped below the level of the surrounding water table, the desalinated 
water flows through the opening 16 into the well so that desalinated water 
may be continuously pumped out of the well by pump 20 at controlled rates. 
The addition of Amate tree sap to the area "A," as described above, assists 
in separating dissolved compounds from the layer of desalinated water into 
the underlying layer of brine solution Throughout area "A" and at the 
front of the well 14, the heavier saline solution gravitates downward and 
is dispersed into the underlying sands, and has to be discharged. 
Preferably, the sap is mixed with a suitable solution before being applied 
to area "A" to increase the water desalinization in the shell layer. The 
sap solution is applied in sufficient quantities so as to permeate both 
the sand and the shell layers in area "A." Additional sap solution is 
added to area "A" from time to time, depending on the amount of water 
passing through the system. 
The filter materials contained in the barrier 10 preferably comprise 
numerous constituents that are insoluble in water and are tightly packed 
to form a substantially solid wall. The filter materials may comprise 
silicon, aluminum, iron, copper, lead and/or nickel, with lesser amounts 
of aluminum oxide and/or chromium. Also copper, potassium and/ or 
phosphorus may be added in a liquid feed. 
The sap of the Amate tree is of the Ficus family and is mixed in a solution 
composed of latex, copper sulfate, diluted ocean water and fresh water. 
When the contents of the well 14 are pumped out, water will flow through 
the shell layer 18 into the well through opening 16 to re-establish the 
static water level in the well. The barrier 10 may be formed of containers 
or the like which are closely fitted together to form a solid wall. The 
sides of the containers are perforated to permit the sea water to flow 
through the barrier 10 and across area "A" into the well 14, whenever the 
water level in the well is pumped below the static level of the 
surrounding water table, which will vary with the degree of tide. 
The barrier containers are filled with the selected mixed filter materials. 
These materials do not dissolve, but act as a means to help separate the 
desalinated water from the saline solution, as explained above. As also 
explained, the area "A" between the barrier 10 and the well 14 is treated 
with the sap or purifying agent which acts further to keep separate 
dissolved compounds from the desalinated water, as the water passes into 
the opening 16 and 14. 
The invention provides, therefore, a practical inexpensive system for 
rejecting the saline constituents of sea water in order to produce 
desalinated water appropriate for irrigation and other purposes. The 
system, as described, is intended to operate under the sand of an ocean or 
other beach where salt water normally underlies the sand and a layer of 
fossilized shells is present beneath the same. 
Although particular embodiments of the process and apparatus of the 
invention have been described, the claims of the process are intended to 
cove all forms of desalination of sea or brackish water using the sap, in 
whatever form or condition utilized, of the Amate tree or other similar 
reacting sap. 
While a particular embodiment of the invention been shown and described, 
modifications may be made. The following claims are intended to cover all 
such modifications as fall within the spirit and scope of the invention.