WO2021234516A1

WO2021234516A1 - Systems and methods of constructing intake-output assemblies for water desalination plants

Info

Publication number: WO2021234516A1
Application number: PCT/IB2021/054085
Authority: WO
Inventors: Levy AMNON
Original assignee: Namaya Ltd
Priority date: 2020-05-20
Filing date: 2021-05-13
Publication date: 2021-11-25
Also published as: GB2595270A; GB202007511D0; GB2595270B

Abstract

A saltwater desalination plant with intake-outtake assembly and a method of constructing such intake-outtake assembly are disclosed, where an elongated circular lumen of the intake assembly for collecting saltwater from a saltwater source is formed within an elongated lumen of the outtake assembly for disposing said brine into said saltwater source, in a single infrastructure tunnel.

Description

SYSTEMS AND METHODS OF CONSTRUCTING INTAKE-OUTPUT

ASSEMBLIES FOR WATER DESALINATION PLANTS

TECHNICAL FIELD [0001] In general, the present invention pertains to the arts of civil engineering and infrastructure construction. In particular, the invention relates to systems and methods of constructing intake-output assemblies for water desalination plants.

BACKGROUND ART

[0002] It is believed that the current state of the art is represented by the following patent literature US3388724, US4793736, US4966494, US5211507, US6109305, US6772840, US7866708, US8231306, USRE35271 ,

US2005061472, US2017130537, CN104632234, CN106869959, CN202117676U, CN203239355U, JP2004130180, JPH0762432, DE3407384

[0003] US8231306 which is believed to be the most pertinent prior art teaches advancing pipe elements for constructing an elongate structure in a soft, stony, rocky, and/or monolithic ground. US8231306 teaches determining the force of advancement, the eccentricity thereof in relation to the neutral axis and/or the direction of advancement with the aid of a pressing device and extension elements which are filled with fluid and are disposed on the face of the joints of the tubing. The fluid pressure in US8231306 is measured in at least one portion of the extension elements which extends along the entire length of the tubing and/or the deformation is measured in some of the joints. The force of advancement and the eccentricity in US8231306 are calculated from said parameters and the values are stored and/or are compared to stored standard values. [0004] Saltwater is desalinated to produce water suitable for human consumption, industry or irrigation. A by-product of desalination is salty brine. Desalination is implemented in many offshore facilities. Most of the modern interest in desalination is mainly focused on cost-effective provision of fresh water for human use. Along with recycled wastewater, desalination is one of the few rainfall- independent water sources.

BRIEF SUMMARY

[0006] In accordance with some aspects and embodiments of the present invention, a saltwater desalination plant is provided, including: an intake assembly including an elongated circular lumen, configured for collecting saltwater from a saltwater source, in where elongated circular lumen of the intake assembly has a circular cross-section along its length to enable passage of a maintenance pig; a desalination facility, configured to perform a desalination process of the saltwater, resulting freshwater and brine; an outtake assembly including at least one elongated lumen, configured for disposing the brine into the saltwater source; characterized by that the elongated circular lumen of the intake assembly is formed within the elongated lumen of the outtake assembly, in a single infrastructure tunnel, in which an incoming flow of the saltwater is conducted inversely and in parallel to an outgoing flow of the brine, within the single infrastructure tunnel, and that the desalination installation plant including a terminal installation, associated with the saltwater source, configured for diverting the incoming flow of the saltwater offset to the outgoing flow of the brine.

[0007] In some embodiments, the outtake assembly is formed from a plurality of cylindrical prefabricated members.

[0008] In some embodiments, the intake assembly is formed subsequently to constructing at least a substantial portion of the outtake assembly.

[0009] In some embodiments, the intake assembly is a continuous pipe through the outtake assembly.

[0010] In some embodiments, the intake assembly comprises a plurality of prefabricated cylindrical members joined in tandem.

[0011] In some embodiments, the single infrastructure tunnel further comprises at least one conduit, configured for conveying at least one member selected from the group consisting of: power electrical cables, pneumatic lines, hydraulic lines, optical fibers, data lines, control, chemicals lines, to and from equipment at the terminal installation of the desalination plant.

[0012] In some embodiments, the said at least one elongated lumen of said outtake assembly at least partially surrounds said elongated circular lumen of said intake assembly to facilitate heat exchange between a relatively warm brine outflow and a relatively cool saltwater inflow.

[0013] In some embodiments, the at least one elongated lumen of the outtake assembly essentially surrounds and engulfs the elongated circular lumen of the intake assembly.

[0014] In accordance with some aspects and embodiments of the present invention, a method of constructing an intake-output assembly for a desalination plant with a plurality of parallel lumens includes: forming an intake assembly including an elongated circular lumen, configured for collecting saltwater from a saltwater source, where elongated circular lumen of the intake assembly has a circular cross-section along its length to enable passage of a maintenance pig; forming an outtake assembly including at least one elongated lumen, configured for disposing a brine into the saltwater source; where the elongated circular lumen of the intake assembly is formed within the at least one elongated lumen of the outtake assembly, in a single infrastructure tunnel; forming a terminal installation, associated with the saltwater source, configured for diverting the incoming flow of the saltwater offset to the outgoing flow of the brine; in which an incoming flow of the saltwater is conducted inversely and in parallel to an outgoing flow of the brine, within the single infrastructure tunnel. [0015] In some embodiments, the forming of the intake assembly is performed subsequently to constructing at least a substantial portion of the outtake assembly.

[0016] In some embodiments, the intake assembly is a continuous pipe and the step of forming the intake assembly comprises continuously drawing the continuous pipe into outtake assembly.

[0017] Some embodiments further include deploying at least one conduit within the single infrastructure tunnel, configured for conveying at least one member selected from the group consisting of: power electrical cables, pneumatic lines, hydraulic lines, optical fibers, data lines, control, chemicals lines, to and from equipment at the terminal installation of the desalination plant.

[0018] In some embodiments, the forming of the outtake assembly comprises forming of the outtake assembly from a plurality of cylindrical prefabricated members.

[0019] In some embodiments, the forming of the intake assembly intake assembly comprises joining, for example by welding, a plurality of prefabricated cylindrical members in tandem.

[0020] In some embodiments, the method further comprises at least partially surrounding said at least one elongated circular lumen of said intake assembly with said at least one elongated lumen of said outtake assembly to facilitate heat exchange within the infrastructure tunnel between the at least one elongated lumen of the outtake assembly and the circular elongated lumen of the intake assembly.

[0021] In some embodiments, the at least one elongated lumen of the outtake assembly essentially surrounds and engulfs the elongated circular lumen of the intake assembly

DEFINITIONS

[0022] The terms desalinate and desalination as referred to herein is to be construed as including any process that takes away mineral components from saline water, such as seawater. More generally, desalination may refer to any of several processes to remove an amount of salt and/or other minerals or components from saline water (i.e., water that contains a concentration of at least one dissolved salt). In some embodiments of the disclosed systems, desalination is removing an amount of salt and/or other minerals or components from saline water so that the water is fit for consumption by a living organism and/or make the water potable. In certain embodiments the living organism is a "mammal" or "mammalian", where these terms are used broadly to describe organisms which are within the class mammalia, including the orders carnivore, rodentia and primates or humans. In some embodiments of the disclosed systems, desalination is removing an amount of salt and/or other minerals or components from saline water so that the water is fit for a specific purpose (e.g., irrigation or industry).

[0023] By "operationally connected" and "operably coupled", as used herein, is meant connected in a specific way (e.g., in a manner allowing water to move and/or electric power to be transmitted) that allows the disclosed system and its various components to operate effectively in the manner described herein.

[0024] The disclosed systems, in certain instances, optionally include one or more desalination plants. As used herein, the term "desalination plant" refers to a facility configured and/or used for desalinating water. In some embodiments, desalination plants house components for desalinating water. In some variations, desalination plants operate by distillation (e.g., vacuum distillation). Desalination plants may be configured to boil water (e.g., saltwater) and collect water (e.g., water vapor) having a significantly reduced or eliminated salt concentration. In some versions, desalination plants operate by multistage flash distillation. As such, desalination plants may be configured to operate by one or more processes that distill water (e.g., seawater). Certain variations of desalination plants are configured to desalinate water by using either distillation or reverse osmosis processes. It should be appreciated however that a plant is referred to as a desalination plant regardless of the nature of the desalination process implemented in the plant.

[0025] In certain embodiments, desalination plants of the disclosed systems are reverse osmosis desalination plants. In some aspects, reverse osmosis desalination plants use pressure and/or one or more semipermeable membranes to desalinate water. In certain versions of reverse osmosis desalination plants, water is passed through one or more semipermeable membranes in order to remove salt and/or minerals and/or other impurities therefrom. In some instances, the efficiency of a desalination process of a reverse osmosis desalination plant is higher if the temperature of the water input (e.g., salt water) into the desalination process is higher. In various embodiments, a desalination process of a reverse osmosis desalination plant uses less energy per volume of water desalinated if the temperature of the water input (e.g., salt water) into the desalination process is higher.

[0026] By desalinating water, in some aspects, desalination plants may produce desalinated water and/or brine (e.g., both desalinated water and brine). As used herein, the term "brine" refers to a solution discharged from a desalination plant. In select aspects, brine may be a solution (e.g., a concentrate) including salt (e.g., sodium chloride) and water. In select versions, brine has a salt concentration in the range 1% to 10%, 3.5% to 26% or 5% to 26%. In certain embodiments, brine includes one or more of the impurities removed from water during desalination (e.g., minerals or other components). In some instances, brine may include residues of chemicals used to treat (e.g., clean) a desalination plant.

[0027] The term structured as referred to herein is to be construed as including any geometrical shape, exceeding in complexity the shape of a single cylindrical, elliptical, polygonal or any combination thereof contour, of elongated shell or pipe. A plain singular cylindrical, elliptical and/or polygonal layout pipe thus does not constitute an example of structured geometry. A pair of coaxial or paralleling plain singular cylindrical, elliptical and/or polygonal layout pipes, however, constitutes an example of structured geometry. [0028] The term tunneling, as referred to herein, is to be construed as encompassing various methods and techniques of tunnel excavation, in a non limiting manner including: (1) track-mounted excavating machines that have powerful cutting booms and are commonly used in coal mining or civil engineering works that require a range of tunnel diameters, colloquially referred to as Roadheaders. Track-mounted excavating machines or Roadheaders are relatively flexible and can be fitted with extra equipment such as gathering arms for the spoil, water jets to reduce dust, and conveyors for removing debris; (2) open-cut method sometimes referred to as ‘cut-and-cover’, involving the construction of an open trench within which the tunnel is constructed, the trench is then backfilled, depending on the ground conditions, the side walls may be constructed before the trench is create or after, cut-and-cover involves creating the ‘roof slab of the tunnel first, within a shallow trench, the trench can then be backfilled and the tunnel constructed underneath the ‘cover’, having the advantage of releasing the site above the tunnel for other uses; (3) immersed-tube method this method is suitable for tunnels that cross deep water, prefabricated sections of either concrete or steel tunnel are lowered into a prepared trench at sea or riverbed level, the trench is then backfilled and any necessary protection constructed above; (4) pipe-jacking or pipe ramming is a trenchless technology in which a drive pit is constructed and then sections of steel or concrete tube are hydraulically jacked forward from the pit to form the tunnel lining, particularly suitable for installing services under canals, railway embankments and roads where it is important that there is little disturbance; (5) auger-boring uses a non-steerable rotating cutting head and is used mainly for conduit installation, a rail-mounted machine augers the soil as it pushes a sleeve or tube into the ground, the auger cuts the face of the borehole as it turns, transporting the excavated spoil back down the sleeve into the shaft, a length of sleeve is inserted by the machine which then withdraws to have another length of sleeve welded on and the auger flight extended; (6) whole face or ‘full-face’ boring and/or tunnel boring machines using purpose-designed tunnel boring machines (TBM) to excavate the full cross-section required, whole face borers grip the side of the tunnel to transmit thrust forward and can cut through hard rock, with debris being removed by conveyor; (7) segmental tunnel linings is a process varying depending on the ground conditions, linings can be performed segments or in-situ concrete that is sprayed in position or cast in place, in soft ground, linings must support the loads imposed by the ground as well as withstanding jacking pressures from the tunneling equipment; (8) segmental cast-iron lining is commonly-used in soft ground as it is durable and has high compressive strength, precast concrete linings are more economical, although it can be difficult to achieve water tightness, in ground that is self-supporting, expanding tunnel linings can be used, the tunneling shield is pushed forward leaving behind it an unsupported space, the lining, made up of precast segments, is then erected and expanded against the ground to predetermined pressure, in hard ground, the lining can be concrete sprayed between steel ribs or onto mesh which has been fixed to the rock face. [0029] The terms pigging as referred to in pipeline transportation industry is to be construed as any practice of using devices known as pigs or scrapers to perform various maintenance operations. Pigging operations include but are not limited to cleaning and inspecting the pipeline. Pigging is accomplished by inserting the pigging device into a pig launcher. The pressure-driven flow of the product in the pipeline is used to push the pigging device along the pipe until the pigging device reaches the terminus of the pipeline.

[0030] Whenever in the specification hereunder and particularly in the claims appended hereto a verb, whether in base form or any tense, a gerund or present participle ora past participle are used, such terms as well as preferably other terms are to be construed as actual or constructive, meaning inter alia as being merely optionally or potentially performed and/or being only performed anytime in future. The terms essentially and substantially, or similar relative terms, are to be construed in accordance with their ordinary dictionary meaning, namely mostly but not completely.

[0031] As used herein, the term “or” is an inclusive “or” operator, equivalent to the term “and/or,” unless the context clearly dictates otherwise; whereas the term “and” as used herein is also the alternative operator equivalent to the term “and/or,” unless the context clearly dictates otherwise. [0032] It should be understood, however, that neither the briefly synopsized summary nor particular definitions hereinabove are not to limit interpretation of the invention to the specific forms and examples but rather on the contrary are to cover all modifications, equivalents and alternatives falling within the scope of the invention.

DESCRIPTION OF THE DRAWINGS

[0033] The present invention will be understood and appreciated more comprehensively from the following detailed description taken in conjunction with the appended drawings in which:

[0034] FIG 1 is a schematic diagram view of desalination plant known in the art;

[0035] FIG 2 is a schematic side-view diagram of an intake-output assembly and terminal installation for desalination plants, in accordance with some embodiments of the present invention;

[0036] FIG 3A is a perspective cross-sectional view of a pipeline set, of intake-output assembly for water desalination plants, in accordance with some embodiments of the present invention;

[0037] FIG 3B is a frontal cross-sectional view of a pipeline set, of intake- output assembly for water desalination plants, in accordance with some embodiments of the present invention;

[0038] FIG 4A is a perspective cross-sectional view of a pipeline set, of intake-output assembly for water desalination plants, in accordance with some other embodiments of the present invention;

[0039] FIG 4B is a frontal cross-sectional view of a pipeline set, of intake- output assembly for water desalination plants, in accordance with some other embodiments of the present invention. [0040] While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown merely by way of example in the drawings. The drawings are not necessarily complete and components are not essentially to scale; emphasis instead being placed upon clearly illustrating the principles underlying the present invention.

DETAILED DISCLOSURE OF EMBODIMENTS

[0041] Prior to elaborating any embodiment of the present invention, in order to present the background of the inventive concept more clearly, reference is firstly made to FIG 1, showing an example of prior art desalination plant 50. Desalination plant 50 comprises pipe 54, which is configured to convey saline water W, typically seawater, to desalination facility 52. Portion of pipe 54 is located offshore and is typically embedded within the seabed, whereas the other portion is installed beneath the ground, and is drawn to desalination facility 52. Pipe 54 comprises intake suction heads 58 typically furnished with filters, configured to filter out undesired matter.

[0042] Desalination plant 50 further comprises pipe 56, which is configured to convey brine from desalination facility 52 to the source of saline water W or elsewhere. Disperser 59 is configured for dispersing brine according to preset environmental standards, by permitting the discharge of brine across a substantially surface area. Similarly, to pipe 54, pipe 56 extends underground from the desalination facility 52 to the source of saline water W. The installation of the portion of pipe 56 underground is typically performed in the art by using pipe ramming as well.

[0043] Illustrative embodiments of the invention are described below. In the interest of clarity, not all features of actual implementation are described in this specification. It will of course be appreciated that in the development of any such actual embodiment, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with technology- or business-related constraints, which may vary from one implementation to another. Moreover, it will be appreciated that the effort of such a development might be complex and time-consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure.

[0044] In accordance with some preferred embodiments of the present invention, reference is now made to FIG 2, showing exemplary installation of desalination plant 10. Desalination plant 10 comprises intake-output assembly 16 and terminal installation 22. Intake of saline water W is exemplarily drawn into manifold 18 typically via filters 28 and then into channel 20 of conduit 16. Channel 20 is preferably formed about the longitudinal centerline of conduit 16. Channel 20 preferably embodies a circular shape, in a non-limiting manner configured for common maintenance procedures, such as cleaning, pigging and/or repair. [0045] Channel 20 for intake of saline water W in conduit 16 is operationally connected to desalination plant 52. Output of brine from desalination facility 52 is transferred to terminal installation 22, in a non-limiting manner via at least one channel 30, formed in conduit 16, typically at the circumference of conduit 16. Brine is further transferred from terminal installation 22 via pipe 26 to disperser 59, configured for dispersing the brine according to preset environmental standards, by permitting the discharge of brine across a substantially surface area.

[0046] As previously mentioned, the efficiency of a reverse osmosis process is typically related to the temperature of the water input (e.g. saltwater). Therefore, in some preferred embodiments, particularly where the desalination is a reverse osmosis process, conduit 16 is constructed in such a manner that heat is substantially effectively exchangeable between the brine outflow transferred in at least one channel 30 of conduit 16 and saline water W inflow drawn via channel 20 of conduit 16. In such embodiments where conduit 16 is constructed to facilitate heat exchange between the relatively warm brine outflow and relatively cool saline, conduit 16 is constructed to maximize the surface area of the partition between brine channels 30 and saline channel 20. In such embodiments where conduit 16 is constructed to facilitate heat exchange between the relatively warm brine outflows and relatively cool saline, brine channels 30 essentially surround and engulf saline channel 20.

[0047] In accordance with some embodiments of the present invention, reference is now made to FIG 3A and 3B showing a perspective cross-sectional view and frontal cross-sectional view of pipeline set 60. Pipeline set 60 comprises tunnel 62, pipe 66 and preferably conduits 70. In the embodiments shown in FIG 3A and 3B pipe 66 is disposed on top of conduits 70, so that conduits 70 are configured to support pipe 66. The installation of tunnel 62 of pipeline set 60 underground is optionally performed by using pipe ramming.

[0048] Accordingly, tunnel 62 of pipeline set 60 is optionally constructed by forcing prefabricated members through the ground, e.g. by pushing cylindrical prefabricated concrete lining members in-tandem from an access pit, thereby forming tunnel 62. It should be noted that the pushing of prefabricated concrete lining members from an access pit is merely an example, whereas in other examples the lining is pushed without any access pits, from the surface into the ground and/or into a side of a hill. [0049] The installation of tunnel 62 of pipeline set 60 underground is optionally performed by a means of segmental tunnel lining process. Accordingly, tunnel 62 of pipeline set 60 is optionally constructed by a tunnel boring machine (TBM) for automated removal of the soil or soil mixed with slurry and for erecting or building a new tunnel segment ring. The segmental tunnel lining process usually eploys precast concrete segments which form rings. The using of precast moulded lining sections disclosed inter alia by James Henry Greathead in US432871.

[0050] It is noted that the shape of pipe 66 is preferably circular, in a non limiting manner enabling common industry maintenance procedures, such as pigging. Pipe 66 of pipeline set 60, shown in FIG 3A and 3B, is an example of channel 20 in conduit 16 shown in FIG 2. Pipe 66 of pipeline set 60 is laid within or threaded into tunnel 62, typically after completion of its constriction.

[0051 ] Pipe 66 of pipeline set 60 is optionally made of steel and/or polymeric materials, as well as combination thereof. In some examples a continuous and somewhat flexible polymeric pipe 66 is continuously threaded into tunnel 62, whereas in other examples pipe 66 is assembled from a plurality of precast segments, which are welded or otherwise joined, typically at the access point to tunnel 62 or within tunnel 62.

[0052] In the examples of continuous and somewhat flexible polymeric pipe 66 continuously threaded into tunnel 62, such somewhat flexible polymeric pipe 66 is optionally drawn towards the terminal installation of tunnel 62, such as terminal installation 22 of desalination plant 10 shown in FIG 2, by optionally gripping the terminal portion of such somewhat flexible polymeric pipe 66 and towing or pulling it towards the terminal installation of tunnel 62, by a means of cables and/or straps that are drawn and pulled from the terminal portion of tunnel 62. In the examples of pipe 66 assembled from a plurality of precast segments, within tunnel 62, optionally specialized equipment and/or personnel are allowed into tunnel 62, welding or otherwise joining, individual precast segments forming pipe 66. [0053] Non-circular lumens of pipeline set 60, such as lumen 64 within tunnel 62, are configured for conducting the output of brine from the desalination plant, such as desalination plant 52 shown in FIG 1. Non-circular lumen 64 does not enable pigging maintenance procedure, however brine output channels do not sustain biological growth and/or biofilm and thus do not require pigging. Tunnel 62 of pipeline set 60, shown in FIG 3B and 3B, is an example of channel 30 in conduit 16 shown in FIG 2.

[0054] In some embodiments tunnel 62 is configured to take brine 64 out of desalination plant 10, whereas pipe 66 is configured to receive seawater 68 into desalination plant 10. In some preferred embodiments tunnel 62 and pipe 66 are further configured to function as a heat exchanger, between the warm brine output and the cool seawater intake, thereby improving the efficacy of the desalination process.

[0055] In some examples, conduits 70 are configured to operationally connect and/or power and/or control and/or monitor the equipment at the terminal installation of tunnel 60, such as terminal installation 22 of desalination plant 10, shown in FIG 2. Pipeline set 60 optionally embodies intake-output assembly 16 shown in FIG 2 and is configured for conducting seawater to and brine from desalination plant 10. In some examples conduits 70 are configured to convey electrical cables, pneumatic lines, hydraulic lines, optical fibers, as well as any other data, control and/or chemicals line, to and from the equipment at the terminal installation of tunnel 60, such as terminal installation 22 of desalination plant 10, shown in FIG 2.

[0056] In accordance with some embodiments of the present invention, reference is now made to FIG 4A and 4B showing, respectively, perspective and frontal cross-sectional views of pipeline set 80, of intake-output assembly for water desalination plants, in accordance with some embodiments of the present invention. Pipeline set 80 comprises tunnel 82, pipe 86 and conduits 90, 91, and 92. Tunnel 82 of pipeline set 80 is optionally constructed similarly to what has been described hereinabove, similarly to what has been specified hereinabove, with reference to in tunnel 62 shown in FIG 3A and 3B, whether by pipe jacking, segment lining or any other technique.

[0057] In some preferred embodiments, pipe 86 is disposed on the bottom of tunnel 82. Tunnel 82 is configured to support conduits 90, 91, and 92 which are disposed in a tangential manner in-between the exterior bottom portion of pipe 86 and the interior bottom portion of tunnel 82. Pipe 86 of pipeline set 80 is optionally made of steel and/or polymeric materials and typically continuously threaded into tunnel 82 or assembled from a plurality of precast segments welded or otherwise joined, similarly to what has been specified hereinabove, with reference to pipe 66 shown in FIG 3A and 3B.

[0058] In some embodiments tunnel 82 is configured to take brine 84 out of desalination plant 10, whereas pipe 86 is configured to receive seawater 88 into desalination plant 10. Pipe 86 is preferably circular, in a non-limiting manner enabling common industry maintenance procedures, such as pigging. In some preferred embodiments tunnel 82 and pipe 86 are further configured to function as a heat exchanger, similarly to what has been specified hereinabove, with reference to pipe 66 shown in FIG 3A and 3B.

[0059] Pipeline set 80 optionally embodies intake-output assembly 16 shown in FIG 2 and is configured for conducting seawater to and brine from desalination plant 10. Non-circular lumens of pipeline set 80, such as lumen 84 within tunnel 82, are configured for conducting the output of brine from the desalination plant, such as desalination plant 52 shown in FIG 1. Non-circular lumen 84 does not enable pigging maintenance procedure, however brine output channels do not sustain biological growth and/or biofilm and thus do not require pigging. Tunnel 82 of pipeline set 80, shown in FIG 3B and 3B, is an example of channel 30 in conduit 16 shown in FIG 2.

[0060] In some examples conduits 90, 91, and 92 are configured to convey electrical cables, pneumatic lines, hydraulic lines, optical fibers, as well as any other data, control and/or chemicals line, to and from the equipment at the terminal installation of tunnel 80, such as terminal installation 22 of desalination plant 10, shown in FIG 2. In some embodiments, conduits 90, 91, and 92 are configured to operationally connect and/or power and/or control and/or monitor the equipment at the terminal installation of tunnel 80, such as terminal installation 22 of desalination plant 10, shown in FIG 2.

[0061] In some preferred embodiments, conduits 90, 91, and 92 are configured to support pipe 86, serving as the underlaying structure interposed in- between the pipe 86 and tunnel 82. [0062] It will be appreciated by persons skilled in the art that the present invention is not limited by what has been particularly shown and described herein above. Rather the scope of the invention is defined by the claims which follow:

Claims

1. A saltwater desalination plant comprises:

(a) an intake assembly comprising an elongated circular lumen, configured for collecting saltwater from a saltwater source; wherein said elongated circular lumen of said intake assembly has a circular cross-section along its length to enable passage of a maintenance pig;

(b) a desalination facility, configured to perform a desalination process of said saltwater, resulting freshwater and brine;

(c) an outtake assembly comprising at least one elongated lumen, configured for disposing said brine into said saltwater source; said saltwater desalination installation is characterized by that:

(d) said elongated circular lumen of said intake assembly is formed within said elongated lumen of said outtake assembly, in a single infrastructure tunnel; wherein an incoming flow of said saltwater is conducted inversely and in parallel to an outgoing flow of said brine, within said single infrastructure tunnel;

(e) said desalination installation plant comprising a terminal installation, associated with said saltwater source, configured for diverting said incoming flow of said saltwater offset to said outgoing flow of said brine.

2. The desalination plant as in claim 1 , wherein said outtake assembly is formed from a plurality of cylindrical prefabricated members.

3. The desalination plant as in any one of the claims 1 or 2, wherein said intake assembly is a continuous pipe through said outtake assembly.

4. The desalination plant as in any one of the claims 1 or 2, wherein said intake assembly comprises a plurality of prefabricated cylindrical members joined in tandem.

5. The desalination plant as in any one of the claims 1 to 4, wherein said single infrastructure tunnel further comprises at least one conduit, configured for conveying at least one member selected from the group consisting of: power electrical cables, pneumatic lines, hydraulic lines, optical fibers, data lines, control, chemicals lines, to and from equipment at said terminal installation of said desalination plant.

6. The desalination plant as in any one of the claims 1 to 5, wherein said at least one elongated lumen of said outtake assembly at least partially surrounds said elongated circular lumen of said intake assembly to facilitate heat exchange between a relatively warm brine outflow and a relatively cool saltwater inflow.

7. A method of constructing an intake-output assembly for a desalination plant with a plurality of parallel lumens comprises:

(a) forming an intake assembly comprising an elongated circular lumen, configured for collecting saltwater from a saltwater source; wherein said elongated circular lumen of said intake assembly has a circular cross-section along its length to enable passage of a maintenance pig;

(b) forming an outtake assembly comprising at least one elongated lumen, configured for disposing a brine into said saltwater source; wherein said elongated circular lumen of said intake assembly is formed within said at least one elongated lumen of said outtake assembly, in a single infrastructure tunnel;

(c) forming a terminal installation, associated with said saltwater source, configured for diverting said incoming flow of said saltwater offset to said outgoing flow of said brine; wherein an incoming flow of said saltwater is conducted inversely and in parallel to an outgoing flow of said brine, within said single infrastructure tunnel.

8. The method according to claim 7, wherein said forming of said intake assembly is performed subsequently to constructing at least a substantial portion of said outtake assembly.

9. The method as in any one of the claims 7 or 8, wherein said intake assembly is a continuous pipe and wherein said step of forming said intake assembly comprises continuously drawing said continuous pipe into outtake assembly.

10. The method as in any one of the claims 7 or 8, further comprises deploying at least one conduit within said single infrastructure tunnel, configured for conveying at least one member selected from the group consisting of: power electrical cables, pneumatic lines, hydraulic lines, optical fibers, data lines, control, chemicals lines, to and from equipment at said terminal installation of said desalination plant.

11. The method as in any one of the claims 7 or 8, wherein said forming of said outtake assembly comprises forming of said outtake assembly from a plurality of cylindrical prefabricated members.

12. The method as in any one of the claims 7 to 11 , wherein said forming of said intake assembly intake assembly comprises joining a plurality of prefabricated cylindrical members in tandem.

13. The method as in any one of the claims 7 to 12, further comprising at least partially surrounding said at least one elongated circular lumen of said intake assembly with said at least one elongated lumen of said outtake assembly to facilitate heat exchange within the infrastructure tunnel between said at least one elongated lumen of said outtake assembly and said circular elongated lumen of said intake assembly.