JP2001062449A - Desalination method and desalnation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a desalination method to perform an efficient desalination treatment by discharging concentrated discharge water from a pit with less energy without using a large discharge pump with high head. SOLUTION: In the desalination method by which a reverse osmosis module 15 is sunk at the water depth where water pressure not less than reverse osmosis pressure is loaded and the desalination is performed, the reverse osmosis module 15 is arranged at the lower part of a pipe 12 of water to be treated storing the water to be treated in the pit 11 and is loaded with water pressure, and the lower end part of the pipe 12 of the water to be treated is communicated with a discharge pipe 17 for discharging the concentrated water, and a U shaped pipe is formed with both the discharge pipe 17 and the pipe 12 of the water to be treated. Also, while a water level in the pipe 12 of water to be treated is kept higher than a water level in the discharge pipe 17, and while the concentrated discharge water is pumped up with a discharge pump 21 installed at the upper part of the discharge pipe 17, the water to be treated is desalted by the reverse osmosis module 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a desalination method and a desalination system, and more particularly, to a desalination method and a desalination system for producing fresh water from treated water such as seawater or sewage using a reverse osmosis module.

[0002]

2. Description of the Related Art Seawater is desalinated, for example, as a measure to eliminate water shortage in areas with low rainfall, or as an urgent measure when a water supply facility becomes unavailable due to a major earthquake in an urban area. Various techniques for providing drinking water and the like have been proposed.

[0003] Also, when producing clean water from sewage, or when producing pure water from tap water or groundwater, a technology for desalinating the water to be treated is adopted. Furthermore, in the case of using pure water in the semiconductor industry, recycling wastewater, or purifying municipal wastewater, pulp wastewater treatment equipment, oil-containing wastewater treatment equipment, silicone polishing wastewater treatment equipment, gasoline vapor separation equipment, etc. Also, a technology for desalinating the water to be treated is adopted.

[0004] As a water treatment technique for purifying and desalinating water to be treated such as seawater and sewage, membrane separation is generally known. Among them, treatment methods using water pressure as a driving force include microfiltration methods for separating suspended substances, flocs and fine particles of bacteria, and ultrafiltration for separating high molecular substances such as polysaccharides and proteins. And a reverse osmosis method for separating dissolved ions such as chloride ions.

In the reverse osmosis method, a semipermeable membrane having a property of preventing solutes is used, and a high pressure equal to or higher than the osmotic pressure is applied from the solution side so that only fresh water passes through the semipermeable membrane. Such a reverse osmosis membrane is incorporated into a reverse osmosis module to perform desalination in order to achieve practical use on an industrial scale. The reverse osmosis module supplies, for example, a solution such as seawater to the reverse osmosis module under high water pressure as a water to be treated, and collects fresh water that has passed through the reverse osmosis membrane into a water collecting pipe by this pressure so that the water can be extracted. Device.

In a general treatment method using such a reverse osmosis module, the reverse osmosis membrane requires a high water pressure of, for example, about 30 kgf / cm ² or more in order to exhibit its function. Requires a large-scale pressure vessel to load the reverse osmosis module, and consumes a large amount of energy as a power for continuously applying such a high pressure.

On the other hand, in Japanese Patent Application Nos. 8-320152 and 8-320153, a reverse osmosis module is immersed in a water depth at which a water pressure equal to or higher than the reverse osmosis pressure is applied. The freshwater penetrating into the water pipe is pumped into the atmosphere via the pumping pipe, creating a pressure difference between the internal pressure of the freshwater collecting pipe and the water pressure to the reverse osmosis module. A technology for desalinating water to be treated such as sewage has been disclosed. According to the desalination treatment method, since a necessary pressure is applied using the water pressure, the energy required for the treatment can be reduced.

[0008]

However, in the conventional treatment method in which the reverse osmosis module is immersed in water at a pressure higher than the reverse osmosis pressure for desalination, the module is separated from the desalinated treated water. Concentrated wastewater was disposed of in the surrounding sea or in a water pressure compensation type storage tank that was provided adjacent to the reverse osmosis module and compensated for storage pressure by pressurized water sent into the tank, If the reverse osmosis module is to be used by placing it in a vertical hole formed underground from the ground, there is a problem with a means for removing concentrated wastewater from the vertical hole.

[0009] That is, since the concentrated wastewater has a large specific gravity, it tends to settle below the vertical hole, and its amount is larger than that of the treated water. It requires a large-scale disposal pump with a high head to pump concentrated wastewater to the ground, and it is not possible to perform efficient desalination treatment by consuming a large amount of energy for disposal of concentrated wastewater.

[0010] In the conventional treatment method in which the reverse osmosis module is submerged in a water depth to which a water pressure equal to or higher than the reverse osmosis pressure is applied to perform desalination, when the reverse osmosis modules are arranged long in the depth direction, the reverse osmosis module is not installed. The water pressure in the lower part is higher than in the upper part (since the hydrostatic pressure increases in proportion to the water depth). Therefore, the desalination treatment by the reverse osmosis module cannot be performed with a uniform pressure difference, and a large load is applied to the lower part, so that the maintenance of the reverse osmosis module becomes difficult.

SUMMARY OF THE INVENTION The present invention has been made in view of such a conventional problem, and the concentrated wastewater is discarded with less energy without using a large-scale and large-scale waste pump. It is an object of the present invention to provide a desalination method and a desalination system capable of performing the following.

Another object of the present invention is to provide a desalination method and a desalination system which enable desalination with an even pressure difference and facilitate maintenance of the reverse osmosis module. .

[0013]

SUMMARY OF THE INVENTION According to the present invention, a reverse osmosis module is submerged at a depth where a water pressure equal to or higher than the reverse osmosis pressure is applied, and fresh water penetrating into a fresh water collecting pipe of the reverse osmosis module is supplied to the atmosphere via a pumping pipe. Pumping it into the tank to generate a pressure difference between the internal pressure of the freshwater collecting pipe and the water pressure to the reverse osmosis module, and using this pressure difference as the reverse osmosis pressure to desalinate the water to be treated such as seawater or sewage. In the desalination method to be performed, the reverse osmosis module is disposed at a lower end of a treated water pipe in which the treated water is stored in a vertical hole formed in the ground from the ground, and the water pressure is loaded, The treated water pipe communicates with a waste pipe that is disposed along the treated water pipe and discharges concentrated wastewater separated from fresh water by the reverse osmosis module, and a U-shape is formed between the treated pipe and the treated water pipe. Forming a tube, and While maintaining the level of the water to be treated in the treated water pipe higher than the level of the concentrated waste water in the waste pipe, the concentrated water is pumped up by the waste pump installed above the waste pipe, and The above object has been achieved by providing a desalination method, wherein desalination of treated water is performed by the reverse osmosis module while supplying water.

In the desalination method according to the present invention, the concentration of the concentrated wastewater is controlled by adjusting the difference between the level of the treated water in the treated pipe and the level of the concentrated wastewater in the waste pipe. It is preferable that the water to be treated is desalinated by the reverse osmosis module (claim 2).
Described invention).

Further, in the desalination method of the present invention, the freshwater collecting pipe communicates with the atmosphere, and the freshwater level in the freshwater collecting pipe is controlled by controlling the amount of freshwater withdrawn through the pumping pipe. Holding it above the reverse osmosis module, and by the pressure of fresh water in the freshwater collecting pipe, the pressure difference between the internal pressure of the freshwater collecting pipe and the water pressure to the reverse osmosis module is extended over the entire length in the depth direction of the reverse osmosis module. It is preferable that the water to be treated is desalinated by the reverse osmosis module while maintaining the water uniformly (the invention according to claim 3).

The present invention also relates to a desalination system for carrying out the above desalination method, wherein the desalination system is inserted along a vertical hole formed in the ground from the ground, and water to be treated such as seawater or sewage is provided. A treated water pipe to be supplied and stored, a reverse osmosis module including a freshwater collecting pipe installed at the lower end of the treated water pipe and communicating with the atmosphere via a ventilation pipe, and disposed along the treated water pipe. Through a reverse osmosis module and communicate with the lower end of the water pipe to be treated, and together with the water pipe to be treated,
A fresh water storage facility that is disposed below the reverse osmosis module and that communicates with the fresh water collection pipe to store fresh water obtained by the reverse osmosis module; and a waste pipe that is installed in the fresh water storage facility. Pump, a pump attached to the pump, extending to the ground to guide fresh water to be pumped to the ground, and a waste pump disposed above the waste pipe to pump concentrated wastewater in the waste pipe The above object has been attained by providing a desalination system comprising: a treated water supply pipe for supplying the treated water from the ground to the treated water pipe. Described invention).

In the desalination system according to the present invention, the waste pipe is a tubular pipe that is disposed so as to cover the outside of the water pipe to be treated and that forms a concentric double pipe together with the water pipe to be treated. It is preferable that the concentrated wastewater flows into a gap between the water pipe to be treated (the invention according to claim 5).

In the desalination system of the present invention, it is preferable that a filling water is filled between the waste pipe and a wall of the vertical hole (the invention according to claim 6).

Furthermore, in the desalination system of the present invention, it is preferable that the water pipe to be treated and the waste pipe are formed of a flexible soft material (the invention according to claim 7).

Further, the desalination system of the present invention comprises:
It is preferable to use an air lift pump as the waste pump (the invention according to claim 8).

In the desalination system of the present invention, it is preferable that the storage facility is a storage room provided in an excavation hole formed by wide excavation of the lower end of the vertical hole (the invention according to claim 9). ).

In the desalination system of the present invention, it is preferable that the storage facility is a pressure-resistant storage tank provided below the water pipe to be treated (the invention according to claim 10).

Further, it is preferable that the pressure storage tank is provided with a weight ballast for preventing lifting (the invention according to claim 11).

Furthermore, the desalination system of the present invention comprises:
Preferably, a compressed air chamber is provided around the storage facility, and the reverse osmosis module is heated by conduction heat from the high-temperature compressed air sent to the compressed air tank.
Described invention).

Here, the reverse osmosis module in the above description cannot be put to practical use with the reverse osmosis membrane itself, so that the reverse osmosis membrane is used as an apparatus using a reverse osmosis membrane in an industrial scale. For example, it is possible to use a flat membrane type (plate, frame) module, a spirally wound type (spiral type) module, a hollow fiber type (hollow fiber type) module and the like, which are already known devices.

Among these reverse osmosis modules, the glue-wound module has the highest membrane filling amount per volume and is most practically used. The flat membrane is adhered in the shape of an envelope, a spacer serving as a permeated water flow path material is placed inside the envelope, and one end of the envelope is opened and connected to a water collecting pipe having many holes, and the raw water flow path is held and The mesh spacer serving as a turbulent flow promoting action is sandwiched between the plurality of envelope-shaped membranes (leaves), and is wound around the water collecting pipe in the form of a roll to form an element.

As the reverse osmosis membrane, a dense active layer having a thickness of 0.1 to 1 μm which exhibits a separating function, such as a cellulose acetate membrane, and a sponge-like support having a thickness of several μm in which many pores exist. It is possible to use a composite membrane composed of an asymmetric membrane composed of layers, a support layer composed of a polysulfone membrane, and a surface active layer composed of a polyamide-based material formed by a technique such as interfacial polymerization, cross-linking treatment, or plasma polymerization. it can.

Further, desalination or fresh water in the above description does not only mean that salt-free water is obtained by removing salt from salt-containing brine, but various water contained in the solution to be treated is included. Is removed through a reverse osmosis membrane and purified, or the purified water obtained thereby is comprehensively meant.

[0029]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. The desalination system 10 according to the first embodiment of the present invention is for desalination of, for example, seawater as the water to be treated. As shown in FIGS. 1 and 2, the desalination system 10 is inserted and arranged along a vertical hole 11 formed from the ground to the ground, and includes a treated water pipe 12 in which seawater as treated water is supplied and stored. The fresh water collecting pipe 1 installed at the lower end of the water pipe 12 to be treated and communicated with the atmosphere through a ventilation pipe 13.
Osmosis module 15 provided with the water pipe 4 and the lower end of the water pipe 12 with the reverse osmosis module 15 interposed therebetween.
2 and a waste pipe 17 that forms a U-shaped pipe, and a pressure-resistant storage tank that is disposed below the reverse osmosis module 15 and that communicates with the freshwater collecting pipe 14 to store fresh water obtained by the reverse osmosis module 15. 18

The desalination system 1 of the first embodiment
According to No. 0, a water pump 19 is installed in the pressure-resistant storage tank 18, and the pressure-resistant storage tank 18 that is extended to the ground and pumped up by the water pump 19.
A pumping pipe 20 for guiding fresh water inside to the ground is attached. A waste pump 21 for pumping concentrated wastewater flowing into the waste pipe 17 is disposed above the waste pipe 17, and a seawater supply pipe 22 for supplying seawater, which is water to be treated, to the water pipe 12 to be treated is provided on the ground. Is provided.

The vertical hole 11 is formed by excavating the rock using various known heavy digging machines. The vertical hole 11 is provided in the reverse osmosis module 15 with, for example, 30 kgf required for reverse osmosis.
/ Cm ² or more, preferably about 60 kgf / cm ² so that the pressure can be applied by the head difference.
It is formed to have a depth of about 300 to 600 m.

The water pipe to be treated 12 is formed in a cylindrical shape using a flexible soft material such as plastic or polyethylene. The to-be-treated water pipe 12 has its lower end joined to the ceiling wall 23 of the pressure-resistant storage tank 18, extends vertically along the vertical hole 11, and has its upper end opened above the ground surface. A reverse osmosis module 15 is installed inside the lower end of the water pipe 12 to be treated, and the upper end 50 of the reverse osmosis module 15 blocks a gap between the upper end 50 and the inner surface of the water pipe 12. A ring-shaped blocking member for closing is provided. by this,
The to-be-treated water supplied to the to-be-treated water pipe 12 passes through the reverse osmosis module 15 without directly flowing into the side of the reverse osmosis module 15 and then passes through the reverse osmosis module 15 as concentrated wastewater separated from fresh water. Flows into At the lowermost end of the water pipe 12 to be treated, a horizontal flow opening pipe 16 that connects the water pipe 12 to be treated and the waste pipe 17 is provided. The water pipe to be treated 12 does not extend to the ceiling wall 23 of the pressure-resistant storage tank 18,
May be directly joined to the upper end of the base.

The reverse osmosis module 15 includes a freshwater collecting pipe 14.
Is provided in the vertical direction while connecting the freshwater collecting pipes 14 with each other, and is provided on the ceiling wall 23 of the pressure-resistant storage tank 18 in an integrated state. It is installed with its lower end supported. The lower end of the freshwater collecting pipe 15 communicating in the up-down direction penetrates through the ceiling wall 23 of the pressure-resistant storage tank 18 and opens into the interior thereof, and the upper end thereof stands upright at the center of the water pipe 12 to be treated. The upper end communicates with a ventilation pipe 13 having an opening to the atmosphere, so that the atmosphere, that is, the air, can be conducted from the atmosphere to the freshwater collecting pipe 14.

The waste pipe 17 is made of a soft material having flexibility similarly to the water pipe 12 to be treated. The waste pipe 17
This is a tubular pipe that is disposed so as to cover the periphery of the water pipe 12 to be treated from the outside and forms a concentric double pipe together with the water pipe 12 to be treated. Concentrated wastewater flows into a gap having an annular cross section between the waste pipe 17 and the to-be-treated water pipe 12, and is stored. The lower end of the waste pipe 17 communicates with the water pipe 12 through the horizontal flow opening pipe 16. The waste pipe 17 forms a U-shaped pipe together with the water pipe 12 with the reverse osmosis module 15 interposed therebetween. I do. At the upper end of the waste pipe 17, a waste pump 21 for pumping concentrated wastewater to the ground is provided.

The pressure-resistant storage tank 18 is a cylindrical closed tank made of, for example, precast concrete covered with a steel plate. Even if the internal pressure is maintained at the atmospheric pressure after being installed at the lower end of the vertical hole 11, the pressure storage tank 18 is loaded from the outer periphery. It has a structure that can withstand the required water pressure. Pressure storage tank 1
A ballast filling chamber 24 is provided at the bottom of the tank 8, and is filled with a weight ballast made of lead or the like, so that the pressure-resistant storage tank 18 does not float due to buoyancy even if the inside becomes hollow. The pressure-resistant storage tank 18 is provided with a support base 25 on the upper surface side of the ceiling wall 23. The lower end of the reverse osmosis module 15 is supported by the ceiling wall 23 via the support base 25 and The lower ends of the treated water pipe 12 and the waste pipe 17 are connected to the support base 25.
Through the ceiling wall 23. Further, in the pressure-resistant storage tank 18, the lower end of the freshwater collecting pipe 14 is opened at the ceiling portion, and a water pump 19 is installed inside.

The pump 19 is a multi-stage turbine type pump, and has a head and a driving force sufficient to pump fresh water accumulated in the pressure-resistant storage tank 18 to the ground.

Pumping pipe 2 attached to pumping pump 19
Reference numeral 0 denotes, for example, a steel pipe or a flexible chemical rubber pipe, which has a structure capable of sufficiently withstanding a load applied when pumping fresh water from the pressure-resistant storage tank 18. The pumping pipe 20 is connected to the ceiling wall 2 of the pressure-resistant storage tank 18.
3 through which the fresh water is pumped up from the opening at the end thereof and discharged to a fresh water storage tank 26 provided on the ground.

According to the first embodiment, an air lift pump is used as the waste pump 21 provided in the waste pipe 17. The air lift pump is a known pump that uses the principle that when air is blown out from the water, the air rises while increasing its volume due to its buoyancy, thereby pushing up the liquid upward. In this air lift pump, for example, air is supplied from a compressor to a lower part of a pumping pipe arranged in a liquid and blown out, and the liquid is pumped by the buoyancy of the air.

One end of the seawater supply pipe 22 is connected to a seawater storage facility (not shown), and the other end is connected to an upper end opening of the water pipe 12 to be treated. Raw seawater to be fed or pretreated seawater is sequentially supplied to the water pipe 12 to be treated.

According to the first embodiment, the waste pipe 1
The gap between the outer peripheral surface of the pipe 7 and the wall surface of the vertical hole 11 is filled with bentonite muddy water 29 as filling water. The bentonite muddy water 29 presses the inner wall surface of the vertical hole 11 to prevent the inner wall surface from collapsing, and forms a mud cake made of bentonite fine particles on the inner wall surface so that the inner wall surface becomes a stable state. To protect.

According to the first embodiment, the reverse osmosis module 15 is provided with a measurement sensor for measuring the pressure difference between the internal pressure of the freshwater collecting pipe 14 and the water pressure around the reverse osmosis module 15. The pressure difference can be managed.

According to the desalination system 10 of the first embodiment, the reverse osmosis module 15 and the water pipe 12 to be treated are inserted into the vertical hole 11 formed by excavation and filled with the muddy water 29 via the support base 25. The pressure-resistant storage tank 18 to which the waste pipe 17 and the like are attached is installed below the vertical hole 11 by attaching a wire to, for example, the support base 25 and suspending and sinking it using a winch. Such submersion work is performed by the pressure-resistant storage tank 18, the water pipe 12 to be treated, the waste pipe 17
Is filled with seawater or the like to reduce buoyancy. Also,
The laying operation is performed while sequentially adding the to-be-processed water pipe 12, the waste pipe 17, the pumping pipe 20, and the like upward. Since the waste pipe 17 and the pumping pipe 20 are formed from a flexible soft material, the handling of the waste pipe 17 and the pumping pipe 20 which are extended in a considerable length becomes easy, and such a submerging operation is performed. It can be done smoothly.

When the pressure-resistant storage tank 18 is set at a predetermined water depth (for example, 600 m) at the lower end of the vertical hole 11, the water pump 19 is driven to pump up and discard seawater and the like filled in the pressure-resistant storage tank 18. When seawater or the like is pumped from the pressure-resistant storage tank 18, the pressure-resistant storage tank 1
8 and the inside of the freshwater collecting pipe 14 are close to the atmospheric pressure, and a large pressure difference corresponding to the reverse osmotic pressure occurs between the internal pressure of the freshwater collecting pipe 14 and the water pressure applied to the reverse osmosis module 15. Become. By this pressure difference, the seawater in the water pipe 12 to be treated is desalinated by the reverse osmosis module 15, and the obtained freshwater flows into the freshwater collecting pipe 14 and the pressure-resistant storage tank 18 and is replaced with seawater or the like.

The fresh water flowing into the fresh water collecting pipe 14 and the pressure resistant storage tank 18 is pumped up by a water pump 19 and stored in a fresh water storage tank 26 provided on the ground.

According to the first embodiment, the water pump 19
, The level of fresh water flowing into the fresh water collecting pipe 14 is maintained above the upper end of the reverse osmosis module 15 at the uppermost stage, and the reverse osmosis modules connected vertically in four stages The pressure difference is uniformly maintained over the entire length in the 15 depth direction.

That is, the reverse osmosis module 15 is loaded with the hydrostatic pressure P proportional to the depth from the surface of the seawater by the seawater stored in the water pipe 12 to be treated (FIG. 1).
Also, in the freshwater collecting pipe 14, the hydrostatic pressure proportional to the depth from the water surface is increased by the freshwater whose water level is held above the reverse osmosis module 15 in the freshwater collecting pipe 14.
(See L2 in the right chart of FIG. 1).
Therefore, desalination is performed in a state where a pressure difference ΔP obtained by subtracting P ′ from P is applied with a constant magnitude over the entire length of the reverse osmosis module 15, so that the reverse osmosis module 15 functions under the same conditions. Can be easily maintained. The pressure difference ΔP is managed by a measurement sensor provided in the reverse osmosis module 15. Further, by controlling the water level in the freshwater collecting pipe 14, the back pressure P ′ due to freshwater is adjusted to change the pressure difference ΔP (see the broken line in the right chart in FIG. 1), and the reverse osmotic pressure is appropriately controlled. Can be.

The concentrated wastewater from the freshwater and the seawater separated by the reverse osmosis module 15 flows into the side of the reverse osmosis module 15 and further flows into the waste pipe 17 through the horizontal flow opening pipe 16. Accumulated and waste pump 21
Is discharged to the drain tank 27.

According to the first embodiment, the water pipe to be treated 12
And the waste pipe 17 are connected to each other at the lower end thereof through the cross flow opening pipe 16 with the reverse osmosis module 15 interposed therebetween, thereby forming a U-shaped pipe.
Since the water level of the seawater in 2 is kept higher than the water level of the concentrated wastewater in the waste pipe 17, the concentrated wastewater can be drained smoothly and efficiently.

That is, since the water level in the water pipe 12 to be treated is maintained higher than the water level in the waste pipe 17 (head difference h), the water head difference h causes the water pipe 12 to be discarded through the horizontal flow opening pipe 16. Since a flow for pushing out the concentrated wastewater is generated in the pipe 17, the concentrated wastewater smoothly flows into the waste pipe 17 by this flow. Also,
The concentrated wastewater fills substantially the entirety of the waste pipe 17, and the concentrated wastewater is treated in a state where the water level in the waste pipe 17 is kept lower than the water level in the treated water pipe 12 by a predetermined head difference h. 12 naturally flows into the waste pipe 17. Therefore, the waste pump 21 may be provided at the upper end of the waste pipe 17 and pump up only the concentrated wastewater pushed up to the upper end to discard the waste water in order to maintain the head difference h. Without necessity, the concentrated wastewater can be discarded with little energy, and efficient desalination treatment can be performed.

Further, according to the first embodiment, the step of pumping concentrated wastewater from the waste pipe 17 while sequentially supplying seawater from the seawater supply pipe 22 to the water pipe 12 to be treated is controlled, and the inside of the water pipe 12 to be treated is controlled. By appropriately adjusting the head difference h between the level of the seawater and the level of the concentrated wastewater in the waste pipe 17, the reverse osmosis module 15 can desalinate the seawater while controlling the concentration of the concentrated wastewater.

That is, when the head difference h is small, the flow of pushing the concentrated wastewater from the treated water pipe 12 to the waste pipe 17 becomes weak, and the concentrated wastewater stays around the reverse osmosis module 15 for a long time. As the concentration increases, the speed of the desalination treatment can be suppressed. On the other hand, when the water level difference is large, the water pipe 12 to be treated
The flow of pushing out the concentrated wastewater becomes stronger, and the concentrated wastewater stays around the reverse osmosis module 15 only for a short time, so that the concentration becomes low and the speed of the desalination treatment can be accelerated. .

FIG. 3 shows a desalination system 30 according to a second embodiment of the present invention. According to the desalination system 30 of the second embodiment, in addition to the configuration of the desalination system 10 of the first embodiment, a compressed air tank 31 is provided below the pressure-resistant storage tank 18 as a compressed air chamber. .
As described above, according to the present invention, a facility separate from the desalination system 30 can be provided in the vertical hole 11 so that the vertical hole 11 can be effectively used.

The compressed air tank 31 includes the pressure-resistant storage tank 1
Similar to 8, a pre-cast concrete cylindrical closed tank covered with a steel plate, for example, has a structure that can sufficiently withstand the water pressure applied from the outer periphery and the internal pressure due to the compressed air stored inside. A ballast filling chamber 32 is provided at the bottom of the compressed air tank 31, and is filled with a weight ballast made of lead or the like, so that the compressed air tank 31 is prevented from rising due to buoyancy. Further, a compressed air pipe 34 is opened inside the compressed air tank 31 through the ceiling wall 33. The compressed air pipe 34 communicates with a compressed air storage power generation facility (not shown) provided on the ground, and is obtained by operating a compressor or the like using surplus power at night or surplus power generated by natural energy generation. The compressed air thus compressed is sent to the compressed air tank 31 for storage. Also, the compressed air stored in the compressed air tank 31 is appropriately taken out through the compressed air pipe 34, gasified to a high temperature and a high pressure by a combustor in a compressed air storage power generation facility, and the gas is used to rotate a turbine to generate power. As a result, required power can be easily obtained.

According to the desalination system 30 of the second embodiment, the reverse osmosis module 15 is heated by the conduction heat of the high-temperature compressed air stored in the compressed air tank 31, and the reverse osmosis module 15 is heated. As a temperature state for operating properly, desalination can be performed more efficiently. In addition, as a facility provided in the vertical hole 11 together with the desalination system 30, in addition to the compressed air tank 31,
For example, a deep aeration pipe, a seabed deep water intake pipe, and the like can be given.

FIG. 4 shows a desalination system 35 according to a third embodiment of the present invention. The desalination system 35 according to the third embodiment utilizes an abandoned mine of a mine facility. The lower end of the vertical hole 36 is widened and excavated as a pair of horizontal holes 37 and 38 to form an inverted T shape as a whole. By providing a plurality of partitioning plates 46, one of the horizontal holes 37 is provided with a freshwater storage chamber 39 as a freshwater storage facility, and the other horizontal hole 3 is provided with a freshwater storage chamber 39.
8, a compressed air chamber 40 is provided. The reverse osmosis module 15, the water pipe 12 to be treated, the waste pipe 17, and the like are appropriately supported from the bottom surface, the inner wall surface, and the like of the vertical hole 36.

FIG. 5 shows a desalination system 41 according to a fourth embodiment of the present invention. According to the desalination system 41 of the fourth embodiment, the lower end of the vertical hole 42 is widened and excavated concentrically with the vertical hole 42 to form a so-called geodome 43. And the ceiling panel 44 is placed on the geodome 43
By providing and partitioning a partition 45, a fresh water storage chamber 48 and a compressed air chamber 47 as fresh water storage facilities are provided adjacent to each other.

Then, the desalination system 3 of the third embodiment
According to the desalination system 41 of the fifth or fourth embodiment,
The same effects as those of the desalination system 10 of the first embodiment and the desalination system 30 of the second embodiment can be obtained, and the excavation holes formed by widening excavation can be used as they are in the freshwater storage facilities 39, 48 and the compressed air tank 40. , 47, it is possible to provide a desalination system at low cost. In addition, in particular, the desalination system 3 of the third embodiment
According to 5, effective reuse of abandoned mines nationwide can be achieved.

The present invention can be variously modified without being limited to the above embodiments. For example, the waste pipe need not necessarily constitute a double pipe together with the water pipe to be treated, and the waste pump provided above the waste pipe does not necessarily need to be an air lift pump. Further, the present invention is not limited to the case of desalination of seawater, the case of producing pure water from tap water or groundwater, the case of recycling wastewater in the semiconductor industry, or the purification of municipal wastewater, In the treatment of pulp wastewater, the treatment of oily wastewater, the treatment of silicone polishing wastewater, the treatment of gasoline vapor separation, etc., it can be employed in various treatments for purifying such treated water using a reverse osmosis membrane.

[0059]

As described above in detail, according to the desalination method and desalination system of the present invention, the concentrated wastewater is discarded from the vertical hole with little energy without using a large-capacity waste pump with a high head. And efficient desalination treatment can be performed.

Further, the desalination method and the desalination system of the present invention can maintain the internal pressure of the freshwater collecting pipe and the water pressure to the reverse osmosis module by maintaining the freshwater level in the freshwater collecting pipe above the reverse osmosis module. Can be maintained uniformly over the entire length of the reverse osmosis module in the depth direction, thereby facilitating the maintenance of the reverse osmosis module.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view illustrating a configuration of a desalination system according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 3 is a schematic sectional view illustrating a configuration of a desalination system according to a second embodiment of the present invention.

FIG. 4 is a schematic sectional view illustrating a configuration of a desalination system according to a third embodiment of the present invention.

FIG. 5 is a schematic sectional view illustrating a configuration of a desalination system according to a fourth embodiment of the present invention.

[Explanation of symbols]

 10, 30, 35, 41 Desalination system 11, 36, 42 Vertical hole 12 Treated water pipe 13 Ventilation pipe 14 Freshwater collecting pipe 15 Reverse osmosis module 16 Crossflow opening pipe (crossflow opening) 17 Waste pipe 18 Pressure-resistant storage tank (freshwater storage) Facility) 19 Pumping Pump 20 Pumping Pipe 21 Waste Pump 22 Seawater Supply Pipe (Treatment Water Supply Pipe) 23 Ceiling Wall 24 Ballast Filling Room 25 Support Base 26 Freshwater Storage Tank 27 Drain Tank 28 Supply Pump 29 Bentonite Muddy Water (Filled Water) 31 compressed air tank (compressed air chamber) 32 ballast filling chamber 33 ceiling wall 34 compressed air pipe 37,38 side hole 39,48 fresh water storage chamber (fresh water storage facility) 40,47 compressed air chamber 43 geodome 44 ceiling panel 45,46 partition Board

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) B01D 61/12 B01D 61/12 (71) Applicant 000003621 Takenaka Corporation 4 Honcho, Chuo-ku, Osaka-shi, Osaka Chome 1-113 (74) One of the above agents 100076532 Patent Attorney Osamu Hatori (72) Inventor Masao Hayashi 131-1 Wakamatsu, Abiko-shi, Chiba (72) Inventor Ichichi Historic Site 2-5 Shiba, Minato-ku, Tokyo −10 KFC Corporation (72) Inventor Minoru Sakurada 5-8-12 Washio, Atsugi City, Kanagawa Prefecture (72) Inventor Nobuyasu Okuda 1-5-1 Otsuka, Inzai City, Chiba Prefecture Takenaka Corporation In Technical Research Institute (72) Inventor Takafumi Shimokawachi 1-5-1 Otsuka, Inzai City, Chiba Prefecture F-term (reference) 4D006 GA03 HA01 HA19 HA41 HA62 HA93 JA19Z JA53A JA53Z JA67Z KA13 KE03Q KE06P KE06Q KE11Q KE21Q MA01 MA03 MA06 MA22 MA25 MB02 MC18 MC54 NA43 PA01 PA05 PB03 PB08 PB27 PC01 PC23 PC25

Claims (12)

[Claims] 1. A reverse osmosis module is immersed in a depth to which a water pressure equal to or higher than a reverse osmosis pressure is applied, and fresh water penetrating into a fresh water collecting pipe of the reverse osmosis module is pumped into the atmosphere via a pumping pipe, and the fresh water collection is performed. In the desalination method of producing a pressure difference between the internal pressure of the water pipe and the water pressure to the reverse osmosis module, and using the pressure difference as the reverse osmosis pressure to desalinate the water to be treated, such as seawater or sewage, The infiltration module is disposed at a lower end of a water pipe in which the water to be treated is stored in a vertical hole formed from the ground to the ground, and is loaded with the water pressure, and the water pipe to be treated is A waste pipe disposed along the water pipe and discharging concentrated wastewater separated from fresh water by the reverse osmosis module, and the waste pipe and the water pipe to be treated form a U-shaped pipe; and The water to be treated in the water pipe to be treated While maintaining the water level higher than the water level of the concentrated wastewater in the waste pipe, the concentrated water is pumped up by a waste pump installed above the waste pipe, and the reverse osmosis is supplied to the water pipe to be treated. A desalination method, wherein desalination of treated water is performed by a module. 2. The reverse osmosis module controls the concentration of the concentrated wastewater by controlling the difference between the level of the water to be treated in the water pipe to be treated and the level of the concentrated wastewater in the waste pipe. The desalination method according to claim 1, wherein desalination of the treated water is performed. 3. The freshwater collecting pipe communicates with the atmosphere, and the freshwater level in the freshwater collecting pipe is maintained above the reverse osmosis module by controlling the amount of freshwater pumped through the water collecting pipe. The reverse pressure is maintained while maintaining the pressure difference between the internal pressure of the freshwater collection pipe and the water pressure to the reverse osmosis module uniformly over the entire length in the depth direction of the reverse osmosis module by the pressure of the freshwater in the freshwater collection pipe. The desalination method according to claim 1, wherein desalination of the water to be treated is performed by an infiltration module. 4. A desalination system for performing the desalination method according to any one of claims 1 to 3, wherein the system is inserted and arranged along a vertical hole formed in the ground from the ground,
A treated water pipe in which treated water such as seawater or sewage is supplied and stored, and a reverse osmosis module including a freshwater collecting pipe installed at the lower end of the treated water pipe and communicating with the atmosphere via a ventilation pipe, A waste pipe that is disposed along the water pipe to be treated, communicates with the lower end of the water pipe to be treated while interposing the reverse osmosis module, and forms a U-shaped pipe together with the water pipe to be treated, and below the reverse osmosis module. A freshwater storage facility that is arranged and communicates with the freshwater collecting pipe to store freshwater obtained by the reverse osmosis module, a pump installed in the freshwater storage facility, and is attached to the pump and extended to the ground. A pumping pipe for guiding the fresh water to be pumped up to the ground; a waste pump disposed above the waste pipe to pump concentrated wastewater in the waste pipe; and supplying the water to be treated to the water pipe from the ground. Treated water Desalination system, characterized by comprising a sheet tube. 5. The waste pipe is a tubular pipe which is disposed so as to cover the outside of the water pipe to be treated and forms a concentric double pipe together with the water pipe to be treated. The desalination system according to claim 4, wherein the concentrated wastewater is caused to flow into the gap. 6. The desalination system according to claim 5, wherein the outside of the waste pipe is filled with filling water between the outside of the waste pipe and a wall surface of the vertical hole. 7. The desalination system according to claim 5, wherein the water pipe to be treated and the waste pipe are formed of a flexible soft material. 8. The desalination system according to claim 4, wherein an air lift pump is used as the waste pump. 9. The desalination plant according to claim 4, wherein the storage facility is a storage room provided in an excavation hole formed by wide excavating a lower end portion of the vertical hole. system. 10. The desalination system according to claim 4, wherein the storage facility is a pressure-resistant storage tank provided below the water pipe to be treated. 11. The desalination system according to claim 10, wherein the pressure storage tank is provided with a weight ballast for preventing lifting. 12. A compressed air chamber is provided around the storage facility, and the reverse osmosis module is heated by conduction heat from high-temperature compressed air sent to the compressed air tank.
12. The desalination system according to any one of claims 11 to 11.