Synthetic infiltration collection system
The present invention is a filtered seawater collection system for installation at seaside locations. This system filters undesirable elements from seawater including garbage, debris, volatile organics and biologics such as toxic algaes. The resulting filtered seawater is then pumped to a desalination plant for de-salting. This system comprises a subterranean reservoir installed at a sheltered location, such as behind a set of dunes. A borehole is created by directional drilling, the borehole breaking through the surf line and into open ocean. A pipe is laid extending from the reservoir out to the open ocean. The pipe ends in an intake, which is overlapped by gravel packets which act as filtration media. The intake receives water filtered through the gravel packets, which is transported through the pipe to the reservoir.
This patent application claims the benefit of United States provisional patent application Ser. No. 60/737,141, filed on Nov. 15, 2005.
TECHNICAL FIELDThis invention relates to the field of desalination of seawater and more specifically to a system and method for filtering seawater to remove suspended solids, debris and biological material prior to subjecting the seawater to desalination. The system and method of filtering seawater described herein also can be applied to cooling water intakes for power plants.
BACKGROUNDSeawater desalination is becoming-an attractive source of drinking water in coastal states as the costs for desalination decline. A prime consideration for seawater desalination is a source of feed water that is reliable and consistent to sustain operations and produce potable water effectively and efficiently. The amount and quality of feed water entering a desalination plant is greatly dependent upon the placement of the feed water intake. Up to the present time, feed water intakes have been of two basic types, namely: 1) directly from the sea and 2) indirectly from the sea. Each of these types of intakes has significant benefits and significant drawbacks as will be further explained below.
Open ocean intakes, or direct intakes can be as simple as dredged channels through a nearshore region to draw in seawater. More sophisticated direct intakes involve the construction of pipelines from shore to beyond the nearshore, out to waters deeper than 35 meters. Deeper water is desirable in that the intake is less affected by wave and tidal action, but added pumping costs and pipeline costs limit the depth to which direct intakes can be practically placed. Direct intakes are fairly long lived in that they can have a service life of 30-50 years. They also provide an unlimited supply of seawater to a desalination plant as the seawater is pumped directly to the plant. However, a first drawback of direct intakes is that they are hampered by impingement and entrainment of planktonic organisms that require additional filtration and pretreatment once the seawater arrives at the plant, thereby driving up fresh water production costs. Other common problems associated with direct intakes include biological fouling of intake pipes; trash and other debris in intakes; hydrocarbon products occurring in feed water; and recirculation of discharge to intakes. Additionally, uncertain construction permitting outcomes related to direct intakes in light of modified regulatory practices derived from Section 316(b) of the Clean Water Act plague desalination plant developers.
Indirect seawater intakes include vertical beach wells, Ranney wells, and infiltration galleries. Common among these indirect seawater intakes is that they are all dependent upon the nearshore zone geology in which they are placed, to provide a filtered seawater product.
Vertical beach wells are placed near a shoreline, typically very close to the nearshore in order to capture seawater filtering through the local nearshore geology. The beach well is a subterranean reservoir that is sunk with its top portion approximate to sea level, coupled to a pipe that is driven outward from the bottom of the reservoir into the nearshore geology, the pipe having a plurality of through-holes for allowing the flow of seawater into the pipe. The distance that the -pipe can be driven into the surrounding nearshore geology limits the length of pipe. As water flows into the reservoir, it fills the reservoir until the level of water in the reservoir is the same as at sea level. The water is then pumped from the reservoir to the desalination plant to be de-salted. Beach wells are advantageous because they avoid issues related to volatile organic spills and lessen potentially harmful algal blooms. Hence, the water quality provided by beach wells is excellent. However a drawback exists in that the water supply produced by a beach well is totally dependent on hydrogeologic conditions at the site. Furthermore, in comparison to the unlimited seawater supply from direct intakes, beach wells typically provide water volumes in the range of only 400-4000 cubic meters per day.
A Ranney well employs a plurality of radially arranged collector wells located horizontally beneath a beach. The collector wells channel filtered seawater to a central sunken reservoir from which the seawater is pumped to a desalination plant for de-salting. Ranney wells typically have higher infiltration rates than vertical beach wells, in that they can produce filtered seawater volumes in a range of 8,000-20,000 cubic meters per day. However, like beach wells, they are limited by the nearshore geology. Also, Ranney wells can be hampered by silt buildup and may also influence onshore groundwater resources, so careful evaluation of site characteristics must be employed before a Ranney well can be installed.
Indirect seawater intakes also suffer from a shorter life span, usually 15-20 years when compared with the 30-50 year life span of direct intakes. Further, the limitation in production capacity limits the use of indirect seawater intakes to only small desalination plants. Also, due to the fact that indirect seawater intakes must be placed in the nearshore region, they are vulnerable to storm damage or damage from beach erosion.
Present seawater intakes for use with desalination plants require choices and compromises between high volume, long life direct intakes and the low volume, shorter life, but higher water quality provided by indirect intakes. Therefore a need exists for a seawater infiltration system that incorporates the high volume and long life of a direct intake while providing the high water quality of an indirect intake without being limited by surrounding nearshore geology.
The foregoing reflects the state of the art of which the inventor is aware, and is tendered with a view toward discharging the inventor's acknowledged duty of candor, which may be pertinent to the patentability of the present invention. It is respectfully stipulated, however, that the foregoing discussion does not teach or render obvious, singly or when considered in combination, the inventor's claimed invention.
SUMMARY OF THE INVENTIONThe inventive filtered seawater collection system provides high quality water without being dependent upon local nearshore geology. The system also provides water volumes much higher than systems that depend upon indirect intakes that are dependent on nearshore geology. The inventive system's ability to eliminate dependency on local nearshore geology allows it to be placed in coastal areas of the world where the nearshore geology renders indirect intakes an impossibility.
The inventive system is comprised of a subterranean reservoir in communication with the first end of an intake pipe. The reservoir is buried with its top portion at a level approximate to sea level, so that the inflow of water from the intake pipe occurs until the water in the reservoir reaches sea level.
The pipe extends from the reservoir out past the nearshore and into the open ocean where it is preferably anchored to the sea floor. The opposite end of the pipe terminates at an intake area where the pipe is perforated with a plurality of openings. Geological materials, preferably gravel, are filled into porous containers and enclosed therein. The containers are then lowered precisely upon the intake so that the porous containers cover the intake openings. The containers then act as a portable geology causing only filtered seawater to enter the pipe. Undesirable suspended elements such as harmful and toxic algae, other suspended biologics and hydrocarbons are either greatly reduced or eliminated altogether by the invention. The placement of the intake of the present invention in the open ocean also allows the invention to produce volumes of water above that of prior art indirect intake designs.
It is an object of this invention to provide an inventive system and method for filtering seawater that is not dependent upon nearshore geology.
Another object of the invention is to provide an inventive system and method for filtering seawater, which produces a higher volumetric flow of filtered seawater than existing indirect intake systems.
Still another object of the invention is to provide an inventive system which allows desalination plants to be located in areas having undesirable nearshore geology for filtering seawater.
Further objects and advantages of the invention will be brought out in the following portions of the specification, wherein the detailed description is for the purpose of fully disclosing preferred embodiments of the invention, without placing limitations thereon.
BRIEF DESCRIPTION OF THE DRAWINGSThe invention will be more fully understood by reference to the following drawings, which are for illustrative purposes only:
Referring to
The pipe 20 is inserted through a bore 32 drilled into the nearshore geology 22 between the bottom of the reservoir 12 and through the surf line 30. Directional drilling techniques that have been used in the petroleum recovery arts are applied here to place the pipe in the manner shown and described. Directional drilling can produce a bore 32 several hundred yards long or even up to a half-mile or more. The use of directional drilling allows the reservoir 12 to be placed significantly far out of harms way such that damage to the reservoir 12 from natural coastal forces would be a limited possibility.
The reservoir 12 is sunk in the ground at a depth where the top portion 34 of the reservoir is approximately at sea level 26 as shown. The top portion 34 of the reservoir 12 is sloped to approximate the slope of the beach 16 which helps prevent sand erosion around the reservoir 12. Filtered seawater 29 flows into the bottom of the reservoir 12 from the pipe 20 and achieves sea level 26. A submersible pump 36 placed into the reservoir 12 transfers the filtered water to the desalination plant (not shown) for de-salting.
The pipe 20 extends past the surf line 30 and out into the open sea 24 a sufficient distance from shore 38 and at a depth to avoid tidal effects. Generally, the placement of pipe 20 is not limited by water depth. The pipe 20 can be mounted 41 to the sea floor 40 as shown in
Referring also to
An example of a filtration media 54 which enables this invention is a sequence of 27% filter sand (typically NSF/ANSI Standard A8071), flint 10.8% (#20 NSF/ANSI Standard A8072), flint 10.8% (¼ to ⅛, NSF/ANSI Standard A8073), flint 10.8% (½ to ¼ NSF/ANSI Standard A8074), anthracite 14.8% (#1, 0.6 to 0.8 mm, NSF/ANSI Standard A8029), and garnet 24.3% (#30 to #40, NSF/ANSI Standard A8037). Site specific factors can augment this recipe.
Finally, although the description above contains many specificities, these should not be construed as limiting the scope of the invention but as merely providing illustrations of some of the presently preferred embodiments of this invention. This invention may be altered and rearranged in numerous ways by one skilled in the art without departing from the coverage of any patent claims which are supported by this specification.
Claims
1. A system for treating seawater, comprising:
- a pipe for drawing seawater through, said pipe having a first end connected to a subterranean reservoir, said pipe further having a second end comprising an intake, said intake being located in raw seawater;
- a filtration media, said filtration media being contained within a porous container, said container being arranged about said intake to allow raw seawater to be filtered through said filtration media prior to said seawater entering said intake and being drawn through said pipe to said reservoir.
2. A system for treating seawater, comprising:
- a pipe extending through a nearshore region out into the open ocean, said pipe being connected to a subterranean reservoir at a first end of said pipe, said pipe further comprising a second intake end located in the raw seawater, said pipe acting as a conduit for drawing seawater from said intake end to said reservoir; and
- a filtration media contained in porous containers, said containers being positioned upon said intake end of said pipe, wherein said system draws raw seawater through said porous containers and wherein the seawater is filtered through said filtration media prior to being drawn through said intake of said pipe.
3. The system for treating seawater as recited in claim 2, wherein said filtration media filters undesirable elements from raw seawater, said undesirable elements comprising detritus, suspended soils, suspended sediment, planktonic organisms, toxic dinoflagellates and diatoms.
4. The system for treating seawater as recited in claim 2, wherein said filtration media further comprises a geologic filtration media.
5. The system for treating seawater as recited in claim 4, wherein said geologic filtration media further comprises gravel combinations.
6. The system for treating seawater as recited in claim 5, further comprising a gravel combination consisting of 27% filter sand (NSF/ANSI Standard A8071), flint 10.8% (#20 NSF/ANSI Standard A8072), flint 10.8% (¼ to ⅛, NSF/ANSI Standard A8073), flint 10.8% (½ to ¼ NSF/ANSI Standard A8071), anthracite 14.8% (#1, 0.6 to 0.8 mm, NSF/ANSI Standard A8029), and garnet 24.3% (#30 to #40, NSF/ANSI Standard A8037).
7. The system for treating seawater as recited in claim 1, further comprising a bore lining for containing said pipe within.
8. The system for treating seawater as recited in claim 7, further comprising a plurality of pipes being contained within said bore lining, said pipes terminating in a corresponding plurality of said intakes, said plurality of pipes being coupled to said reservoir at a first end of each pipe, wherein each of said intakes receives filtered seawater through a said filtration media container.
9. The system for treating seawater as recited in claim 2, further comprising a bore lining for containing said pipe within.
10. The system for treating seawater as recited in claim 9, further comprising a plurality of pipes being contained within said bore lining, said pipes terminating in a corresponding plurality of said intakes, said plurality of pipes being coupled to said reservoir at a first end of each pipe, wherein each of said intakes receives filtered seawater through a said filtration media container.
11. A system for treating seawater, said system for being placed at shoreline locations, said system comprising an underground subterranean reservoir, said reservoir being placed at least behind a first set of dunes at a shoreline location, said reservoir further comprising a sloped top to conform with the approximate slope of a shoreline at which said reservoir is placed;
- a pipe for drawing seawater there through, said pipe having a first end connected to said reservoir, said pipe extending outward from said reservoir past the shoreline and into open seawater, said pipe terminating in a second end having a plurality of openings for drawing seawater into said pipe; a geologic filtration media enclosed within plurality of porous containers, said filtration media being selectable for optimized filtration characteristics, said plurality of containers being arranged about said second end to allow raw seawater to be first filtered through said filtration media prior to entering said second end openings and being drawn through said pipe to said reservoir.
12. A seawater intake for providing filtered seawater, comprising:
- an intake opening positioned in raw seawater;
- at least one porous and formable container, said container containing a seawater filtration media;
- said container being formably positioned over said intake opening to put said opening in filtering contact with said container for allowing raw seawater to be drawn through said container and said filtration media prior to entering said intake opening.
13. The seawater intake as recited in claim 12, wherein said intake is a component of a desalination plant.
14. The seawater intake as recited in claim 12, wherein said intake is a component of a power plant.
15. The seawater intake as recited in claim 12, wherein said intake is a component of any industrial plant.
16. The seawater intake as recited in claim 12, wherein said seawater filtration media further comprises a geologic filtration media.
17. The seawater intake as recited in claim 16, wherein said geologic filtration media further comprises gravel combinations.
18. The seawater intake as recited in claim 17, further comprising a gravel combination consisting of 27% filter sand (NSF/ANSI Standard A8071), flint 10.8% (#20 NSF/ANSI Standard A8072), flint 10.8% (¼ to ⅛, NSF/ANSI Standard A8073), flint 10.8% (½ to ¼ NSF/ANSI Standard A8074), anthracite 14.8% (#1, 0.6 to 0.8 mm, NSF/ANSI Standard A8029), and garnet 24.3% (#30 to #40, NSF/ANSI Standard A8037).
19. The seawater intake as recited in claim 12, wherein said container further comprises a compartmentalized interior, said filter media being distributed with said compartments.
20. The containers as recited in claim 19, further comprising attachment points for attaching a lifting apparatus to said container.
21. The seawater intake as recited in claim 12, wherein said filtration media filters undesirable elements from raw seawater, said undesirable elements comprising detritus, suspended soils, suspended sediment, planktonic organisms, toxic dinoflagellates and diatoms.
22. A filtration media container, comprising:
- a porous outer cover having a compartmentalized interior;
- a filtration media contained inside of said compartmentalized interior; and
- attachment points for attaching a lifting apparatus to said container.
23. The filtration media container as recited in claim 22, wherein said seawater filtration media further comprises a geologic filtration media.
24. The filtration media container as recited in claim 23, wherein said geologic filtration media further comprises gravel combinations.
25. The filtration media container as recited in claim 24, further comprising a gravel combination consisting of 27% filter sand (NSF/ANSI Standard A8071), flint 10.8% (#20 NSF/ANSI Standard A8072), flint 10.8% (¼ to ⅛, NSF/ANSI Standard A8073), flint 10.8% (½ to ¼ NSF/ANSI Standard A8074), anthracite 14.8% (#1, 0.6 to 0.8 mm, NSF/ANSI Standard A8029), and garnet 24.3% (#30 to #40, NSF/ANSI Standard A8037).
26. The filtration media container as recited in claim 22, wherein said filtration media filters undesirable elements from raw seawater, said undesirable elements comprising detritus, suspended soils, suspended sediment, planktonic organisms, toxic dinoflagellates and diatoms.
27. A seawater intake for providing filtered seawater, comprising:
- A pipe end having an opening; and
- A porous filter, said filter containing a geologic filtration media, said filter and said pipe end coupling together in a sealing manner, wherein raw seawater is drawn through said filter prior to entering said opening in said pipe end.
28. The seawater intake as recited in claim 27, wherein said geologic filtration media further comprises gravel combinations.
29. The seawater intake as recited in claim 28, further comprising a gravel combination consisting of 27% filter sand (NSF/ANSI Standard A8071), flint 10.8% (#20 NSF/ANSI Standard A8072), flint 10.8% (¼ to ⅛, NSF/ANSI Standard A8073), flint 10.8% (½ to ¼ NSF/ANSI Standard A8074), anthracite 14.8% (#1, 0.6 to 0.8 mm, NSF/ANSI Standard A8029), and garnet 24.3% (#30 to #40, NSF/ANSI Standard A8037).
30. The seawater intake as recited in claim 27, wherein said filtration media filters undesirable elements from raw seawater, said undesirable elements comprising detritus, suspended soils, suspended sediment, planktonic organisms, toxic dinoflagellates and diatoms.
Type: Application
Filed: Nov 13, 2006
Publication Date: May 17, 2007
Inventors: Anthony Jones (San Diego, CA), Robert Campbell (Rancho Murieta, CA)
Application Number: 11/599,495
International Classification: E02B 1/00 (20060101);