TW201309597A - Desalinization system and desalinization method - Google Patents

Abstract

The desalinization system (S) in the first present invention, which converts seawater and wastewater to fresh water, is provided with a heat exchanger (6) that exchanges heat between wastewater or treated wastewater and seawater. The desalinization system (S) in the second present invention, which also converts seawater and wastewater to fresh water, is provided with the following: a membrane-separation activated-sludge treatment device (1) that treats wastewater using a membrane-separation activated-sludge method; a first RO membrane (2) that removes salt from the output (s5a) of the membrane-separation activated-sludge treatment device (1) by transferring said salt to first concentrated water (s6), thereby producing industrial-use water (s1); a UF membrane (3) that seawater passes through and that removes particulates from said seawater; a second RO membrane (5), to which treated water (s5b) that has passed through the UF membrane (3) is sent, whereby salt is removed from said treated water (s5b) and transferred to second concentrated water (s7), thereby producing drinking water (s2); and a heat exchanger (6) that exchanges heat between the wastewater or treated wastewater (s5a, s6, s1) and seawater.

Description

Seawater desalination system and seawater desalination method

The present invention relates to a seawater desalination system and a seawater desalination method for desalination (desalination) of seawater and domestic sewage.

In recent years, with the increase in the world population and the progress of large-scale industries including emerging countries, the demand for water for drinking water and industrial water in areas such as sand deserts has increased significantly.

Conventionally, as a system for desalination of seawater and domestic sewage, a seawater desalination system S100 as shown in Fig. 6 is provided.

The manner in which the produced water s101 (industrial water) is produced using domestic sewage in the seawater desalination system S100 is carried out in the manner described below. Also, the salt concentration of domestic sewage is about 0.1%.

The domestic sewage is sent to the MBR (membrane bioreactor; Membrane Bioreactor; MBR) 101 by the pump p101 to separate the activated sludge method, and the MBR101 is used to remove the activated sludge in the domestic sewage and wear it. The MBR permeate water after passing through the MBR 101 is sent to the low pressure RO membrane (Reverse Osmosis Membrane; hereinafter referred to as RO membrane) 102 by the pump p102.

In addition, the MBR permeating water after passing through the MBR101 has a salt concentration of only 0.1%, so the RO membrane system uses a low pressure RO membrane (reverse osmosis membrane), that is, about 1 to 2 MPa (million Pascal). Low pressure RO membrane 102.

The MBR permeated water supplied by the pump p102 is diluted by penetrating the low pressure RO membrane 102, and about half of it is produced as production water s101 (industrial water), and the remaining half is used as salt content. The concentrated water s104 of the impurities is separated and removed.

The salt concentration of the impurity containing salt or the like removed by the low pressure RO membrane 102 has been concentrated to a concentration of about 0.2% of the concentrated water s104 of about 1/2 capacity of the domestic sewage, and is supplied from the low pressure RO membrane 102 to the stirring tank 104. .

The manner in which the produced water s102, that is, the industrial water, is produced from the seawater in the seawater desalination system S100 is carried out in the manner described below. Moreover, the salt concentration of seawater is about 3 to 4%.

The seawater is sent to the UF membrane (Ultrafiltraction Membrane; UF membrane) 103 by the pump p103, and the particles are removed by the UF membrane 103, and then sent to the agitation vessel 104. In the agitation tank 104, the concentrated water s104 having a capacity of about 1/2 of the domestic sewage for the UF membrane which has penetrated the UF membrane 103 and the seawater after the above-mentioned low-pressure RO membrane 102 is concentrated from the domestic sewage. After the stirring, the pump p104 is fed to the medium pressure RO membrane 105.

The UF film that has penetrated the UF film 103 permeates seawater, and although it is a salt concentration of 3 to 4%, it is diluted by the concentrated water s104 having a salt concentration of 0.2%, so that an RO film of about 3 to 5 MPa at a medium pressure can be used ( Reverse osmosis membrane), that is, medium pressure RO membrane 105.

The mixed water s103 fed from the agitation tank 104 to the intermediate pressure RO membrane 105 by the pump p104 is diluted by the intermediate pressure RO membrane 105. The 1/2 degree is produced as the production water s102 (industrial water) which is desalinated, and the remaining 1/2 degree is separated and removed as the brine s105 containing impurities such as salt. In other words, the production amount of production water s102 (industrial water) is equivalent to 1/2 of seawater plus 1/4 of domestic sewage.

That is, the displacement of the brine s105 is 1/2 of that of seawater plus a quarter of the capacity of domestic sewage.

Further, the pressure energy of the brine s105 is recovered by the power recovery device 106 as rotational energy, and is taken as a power source for pressing a part of the mixed water s103 after the pumping back to the intermediate pressure RO membrane 105 ( Energy source) to use.

A conventional seawater desalination system is a seawater desalination system S200 as shown in Fig. 7.

The seawater desalination system S200 does not feed the concentrated water s104 of the domestic sewage in the seawater desalination system S100 of FIG. 6 to the agitation tank 204, but adopts two methods: desalination of domestic sewage and desalination of seawater. A separate process.

In the seawater desalination system S200, although the particles are removed by the UF film 203, the seawater in the agitation tank 204 is not diluted by the water supply from the domestic sewage (the concentrated water s104 of the domestic sewage in Fig. 6). Therefore, the salt concentration is relatively high, about 3 to 4%, and a high pressure RO membrane (reverse osmosis membrane), that is, a high pressure RO membrane 205 of about 6 to 8 MPa must be used.

Seawater desalination system S200, which penetrates domestic sewage through low pressure RO membrane 202 is desalinated to obtain about half of the production water s201 (industrial water) of domestic sewage. On the other hand, in the seawater, the particles are removed by the UF membrane 203, and then passed through the high-pressure RO membrane 205 to be desalinated, and 1/2 amount of production water s203 (drinking water) of seawater can be obtained.

The other structures are the same as those of the seawater desalination system S100 of Fig. 6, and therefore, the components of the seawater desalination system S100 are replaced with the component symbols in the 200-head number, and the detailed description thereof will be omitted.

The conventional seawater desalination system S100 (please refer to Figure 6) is compared with the desalination system S200 (please refer to Figure 7), which has the following advantages.

The first advantage is that, in the seawater desalination system S100 of Fig. 6, the wastewater (concentrated water s104) separated and removed during the process of producing the produced water s101 from domestic sewage is used to produce the produced water s102 from seawater. In the process, therefore, there is an advantage that the production amount of produced water from seawater can be increased.

Specifically, if the wastewater from the domestic sewage (concentrated water s104) is not used, the production water from the seawater is only 1/2 of the capacity of the seawater, but according to the seawater desalination system S100, the domestic sewage can be increased by 1/2. The amount of water in the capacity can be increased to produce water s102 (industrial water).

The second advantage is that the seawater (the salt concentration is about 3 to 4%) is the concentrated water s104 (the salt concentration is 0.2%) separated from the low-pressure RO membrane 102 by the domestic sewage, so the seawater is diluted and the salt concentration is lowered. . Therefore, if the drainage (concentrated water s104) from domestic sewage is not used, the high-pressure RO membrane 205 must be used because the salt concentration is high, but since it is diluted by the concentrated water s104, the medium-pressure RO membrane is used. 105, the power required to pump p104 can be reduced compared to the case of using high pressure RO membrane 205.

Because the penetration pressure (osmotic pressure) relative to the medium pressure RO membrane is about 3 to 5 MPa, the penetration pressure of the high pressure RO membrane is about 6 to 8 MPa. When it is to penetrate the high pressure RO membrane, it must be used in comparison. Greater power (energy) when pressing the RO membrane.

Further, Patent Document 1 is cited as a prior art document in the specification of the present case.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent No. 4481345

However, among the conventional seawater desalination systems S100 and S200, the following problems exist.

The first problem is that the permeability (permeability) of the UF film and the RO film is highly temperature-dependent with the permeated liquid.

Although the seawater desalination systems S100 and S200 can desalinate seawater, seawater is sometimes low in temperature depending on the country and region. This In the case of the seawater desalination system S100, the permeability of the seawater to the UF membrane 103 and the intermediate pressure RO membrane 105 due to the low-temperature seawater is lowered by factors such as an increase in viscosity. Therefore, in order to allow the low-temperature seawater to penetrate the UF film 103 and the medium-pressure RO film 105, the pumps p103 and p104 must use more power, which is a problem that the power consumption becomes larger.

Similarly, in the seawater desalination system S200, the permeability of the seawater to the UF membrane 203 and the high pressure RO membrane 205 is lowered due to the low temperature seawater. Therefore, in order to allow the low-temperature seawater to penetrate the UF film 203 and the high-pressure RO film 205, the pumps p203 and p204 must use more power, which is a problem that the power consumption becomes larger.

The second problem is that in the seawater desalination system S100, the concentrated water s104 separated by the low pressure RO membrane 102 is pumped by the pump p102, but the pressure energy of the concentrated water s104 is not used. Similarly, in the seawater desalination system S200, the brine s202 separated by the low pressure RO membrane 202 is pressurized by the pump p202, but the pressure energy of the brine s202 is not utilized.

Therefore, it is difficult to say that its energy is being used effectively.

The third problem is that the seawater desalination system S100 and S200 are equipped with four pumps. The manufacturing cost, installation cost, and maintenance cost of the pump are all necessary items, which may cause cost increase.

The present invention has been made in view of the above-described actual circumstances, and an object thereof is to provide a seawater desalination system and a seawater desalination method which can effectively utilize energy, have low energy costs.

In order to achieve the above object, the seawater desalination system of the first invention of the present invention is a seawater desalination system that desalinates seawater and domestic sewage, and is a heat exchanger that exchanges heat between domestic sewage or treated water and seawater.

The seawater desalination method of the third invention of the present invention is a method for achieving the seawater desalination system of the first invention of the present invention.

The seawater desalination system according to the second aspect of the present invention is a seawater desalination system that desalinates seawater and domestic sewage, and includes a membrane separation activated sludge treatment device that treats the domestic sewage by membrane separation activated sludge method, The permeated water which has passed through the membrane separation activated sludge treatment apparatus is re-permeated, and the salt is contained in the first concentrated water to be removed, and the first RO membrane of the industrial water is produced, and the seawater is passed through to the seawater. The UF film to be removed by the particles is passed through the treated water which has passed through the UF film, and the salt of the treated water is removed in the second concentrated water to be removed, and the second RO film of the drinking water is produced. A heat exchanger in which sewage or treated water exchanges heat with the aforementioned seawater.

The seawater desalination method of the fourth invention of the present invention is a method for achieving the seawater desalination system of the second invention of the present invention.

According to the seawater desalination system and the seawater desalination method of the present invention, it is possible to achieve a seawater desalination system and a seawater desalination method which can effectively utilize energy, have low energy costs, and have a seawater desalination system.

The embodiment of the present invention will be described below with reference to the drawings.

[Embodiment 1]

Fig. 1 is a conceptual configuration diagram of a seawater desalination system according to Embodiment 1 of the present invention. In the seawater desalination system S of the first embodiment, in order to produce the industrial water s1 from the domestic sewage, the MBR (membrane bioreactor; Membrane Bioreactor) 1 for treating the domestic sewage by the membrane separation activated sludge method is provided. A low-pressure RO membrane (Reverse Osmosis Membrane) 2 which removes impurities such as salt and ions contained in domestic sewage and desalinates domestic sewage.

MBR1 is subjected to solid-liquid separation to separate and remove activated sludge from domestic sewage.

The RO membrane (reverse osmosis membrane) is a semi-permeable membrane that allows water to pass through, but low molecular substances such as salt and ions are not easily passed. The low-pressure RO membrane 2 is because the salt concentration of the domestic sewage is as low as 0.1%, and the low-pressure RO can be removed by using a relatively low permeation pressure (osmotic pressure) of about 1 to 2 MPa (million Pascal). membrane.

Further, the water desalination system S is provided with a UF membrane (Ultrafiltration Membrane) 3 for removing particles contained in seawater in order to produce drinking water s2 from seawater, and has been penetrated by the UF membrane 3 The stirring tank 4 in which the seawater after the removal of the particles is uniformly stirred, and the salt and ions contained in the seawater after the particles have been removed and stirred in the stirring tank 4 A high-pressure RO membrane 5 which is removed by impurities and is desalinated by seawater. Further, the agitation tank 4 has another function of temporarily accumulating seawater to be supplied to the pump p4, and ensuring stable operation of the pump p4.

The UF membrane (ultrafiltration membrane) 3 performs screening and filtration processing of a molecular size level according to the pore diameter of the membrane and the size of the molecule of the object to be removed in the seawater, and removes the particles to be removed.

Since the high-pressure RO membrane 5 has a salt concentration of 3 to 4%, it is necessary to use a relatively high transmission pressure and a high-pressure RO membrane which removes salt by a pressure of about 6 to 8 MPa (million Pascal).

However, the domestic sewage used in the desalination system S is flowed through the ground, so for example, if it is in a temperate zone, it is warmer, and has a temperature of about 15 to 20 °C. On the other hand, the seawater used in the desalination system S is exposed to the atmosphere and is susceptible to climate change, that is, it is easily affected by temperature changes, so in the autumn, there may be 10 °C or so. The low temperature situation occurs.

As described above, the UF film 3 and the high-pressure RO film 5 used for seawater desalination have high temperature dependence on the permeated liquid, and have low permeability (permeability) at low temperatures and high transmittance at high temperatures. Propensity.

Therefore, in the seawater desalination system S, there is a heat exchanger 6 capable of imparting heat exchange to the seawater by the heat energy retained by the domestic sewage. Specifically, the heat exchanger 6 is configured to flow domestic sewage in the flow path r11 upstream of the MBR 1 for the path for desalination of the domestic sewage, and upstream of the UF film 3 flowing through the path for desalination of the sea water. Flow path r2 The sea water is exchanged for heat to transfer the heat of domestic sewage to the sea by heat exchange.

The heat exchanger 6 is constructed by the following various embodiments.

Figure 2 is a conceptual diagram showing various combinations of heat exchangers in a desalination system. Fig. 2(a) is a conceptual diagram showing a heat exchanger that transfers seawater to a domestic sewage flow path for heat exchange; and Fig. 2(b) shows a flow of domestic sewage to seawater. A conceptual diagram of a heat exchanger for performing heat exchange; and Fig. 2(c) is a conceptual diagram showing a heat exchanger for transferring a heat medium to a flow path of domestic sewage and a seawater flow path for heat exchange.

The heat exchanger 6A shown in Fig. 2(a) is formed by flowing seawater in the flow path r2 upstream of the UF membrane 3 to the flow path r11 of the domestic sewage upstream of the MBR 1, thereby The heat energy of the sewage is imparted to the seawater by heat exchange.

The heat exchanger 6B shown in Fig. 2(b) is formed by flowing the domestic sewage of the flow path r11 upstream of the MBR 1 into the flow path r2 of the seawater upstream of the UF membrane 3, thereby discharging the domestic sewage. The heat is transferred to the seawater by heat exchange.

The heat exchanger 6C shown in Fig. 2(c) is formed such that the liquid which is easy to conduct heat, that is, the heat medium n, is pumped p9 so that it is in the flow path r11 of the domestic sewage upstream of the MBR 1 and the UF film 3 The flow in the flow path r2 of the upstream seawater is circulated, and the thermal energy of the domestic sewage in the flow path r11 upstream of the MBR 1 is transported by the heat medium n to the seawater in the flow path r2 upstream of the UF film 3.

These are referred to as: shell and coil type; or shell and tube type heat exchangers 6.

In addition, in the first figure, the heat exchanger 6 is disposed downstream of the pump p1 of the domestic sewage flow path r11 and downstream of the pump p3 of the seawater flow path r2, but The heat exchanger 6 is not limited to the upstream and downstream of the pump p1 of the flow path r11 of the domestic sewage, and can be disposed without being restricted to the upstream and downstream of the pump p3 of the seawater flow path r2.

Further, in the case of the heat exchanger 6A of Fig. 2(a), on the downstream side of the pump p3 of the seawater flow path r2 (please refer to Fig. 1), the flow of the seawater toward the domestic sewage can be obtained. It is more preferable that the pressure of the path r11 (the pressure of the coil or the like provided in the flow path r11) is higher. In this case, the heat exchanger 6A may be provided on either side of the upstream and downstream of the pump p1 of the flow path r11 of the domestic sewage.

Similarly, in the case of the heat exchanger 6B of Fig. 2(b), on the downstream side of the pump p1 of the domestic sewage flow path r11 (please refer to Fig. 1), it is possible to obtain the domestic sewage toward the seawater. The flow of r2 is the pressure of the pressure, so it is better. In this case, the heat exchanger 6B may be provided on either side of the upstream and downstream of the pump p3 of the flow path r2 of the seawater.

Further, the heat exchanger 6 may be selectively used from any one of a countercurrent heat exchanger, a parallel flow heat exchanger, a straight AC heat exchanger, and the like.

Figure 3 is a diagram showing the location of heat exchange between domestic sewage and seawater in a desalination system.

In the seawater desalination system S, the location where the domestic sewage is exchanged with the seawater may be at the position A of the flow path r11 of the domestic sewage upstream of the MBR1 or the position B of the flow path r12 after the MBR1 is penetrated, or Any position of the flow path r13 of the brine s6 removed by the low pressure RO membrane 2 or the position D of the flow path r14 after passing through the low pressure RO membrane 2 may be used.

However, on the upstream side of the flow path of domestic sewage, since domestic sewage has more heat energy, from the viewpoint of heat energy, the best positions are: upstream position A, position B, position C. , the order of position D.

Next, a water-producing process for producing industrial water s1 from domestic sewage in the seawater desalination system S shown in Fig. 1 will be described.

The domestic sewage system is pumped into the seawater desalination system S by the pump p1, and exchanges heat with the seawater flowing through the flow path r2 via the heat exchanger 6, and heat energy is supplied to the seawater and sent to the MBR 1. The domestic sewage system removes activated sludge scum, bacteria, etc. by penetrating through MBR1.

The MBR permeating water s5a of the domestic sewage after passing through the MBR1 is sent to the low pressure RO membrane 2 by the pump p2, and by passing through the low pressure RO membrane 2, the brine s6 containing impurities such as salts and ions is removed, and is Fresh water, and then produce industrial water s1.

The amount of industrial water s1 available is 1/2 of that of domestic sewage. On the other hand, the remaining amount of domestic sewage, that is, the amount of 1/2 of domestic sewage is an impurity containing salt and ions. The brine s6 is removed.

Next, in the seawater desalination system S, the production water, that is, the water production process of the drinking water s2, is produced from seawater.

The seawater is pumped into the seawater desalination system S by the pump p3, and the seawater is heated by the heat energy of the domestic sewage via the heat exchanger 6, and sent to the UF membrane 3. The seawater heated by the heat exchanger 6 penetrates the UF membrane 3 so that the particles in the seawater are removed. The seawater after the particles are removed by the UF film 3, that is, the UF film is stirred into a uniform state in the stirring tank 4 through the seawater s5b.

Then, the stirred UF membrane passes through the seawater s5b and is sent to the high pressure RO membrane 5 by the pump p4. The UF membrane passes through the seawater s5b, and by passing through the high-pressure RO membrane 5, about half is removed as brine s7 containing impurities such as salt and ions, and the remaining half is desalinated and produced as drinking water. S2.

According to the seawater desalination system S of the first embodiment, in the heat exchanger 6, the low-temperature seawater is heated by the heat energy of the domestic sewage having a higher temperature than the seawater, so that the seawater after being heated can be easily And the UF film 3 and the high pressure RO film 5 are well penetrated.

In this way, the pumps p3 and p4 used to pressurize the seawater can reduce their power separately. Therefore, the energy saving of the seawater desalination system S can be achieved.

[Embodiment 2]

Fig. 4 is a conceptual configuration diagram of a seawater desalination system according to a second embodiment of the present invention.

The seawater desalination system 2S of the second embodiment is provided for recycling: The energy recovery device 21 for the pressure energy of the brine s6 in the seawater desalination system S of the first embodiment.

The other components are the same as those of the seawater desalination system S of the first embodiment. Therefore, the same components as those of the first embodiment are denoted by the same reference numerals, and the detailed description thereof will be omitted.

The seawater desalination system 2S system is provided with an energy recovery device 21 that can recover the pressure energy of the brine s6 removed by the low pressure RO membrane 2 as electrical energy or rotational kinetic energy (mechanical kinetic energy).

In the energy recovery device 21, for example, the pressure energy of the brine s6 is used for small-scale hydroelectric power generation by using a water truck or a gear, and mechanical kinetic energy is converted into electric energy (electric power) to be recovered. The electric power recovered by the energy recovery device 21 is used as electric power for pumping seawater to the pump p3 of the UF film 3 (indicated by a broken line in Fig. 4). Further, it may not be used as the power of the pump p3, but may be used as another power source.

Alternatively, it is also possible to use the energy recovery device 21 to recover the pressure energy of the brine s6 as rotational kinetic energy (mechanical kinetic energy) and apply it to the seawater flowing through the UF membrane 3 without setting the pump p3. .

Alternatively, when the rotational kinetic energy (mechanical kinetic energy) recovered by the energy recovery device 21 is not too large, it may be made that the pump p3 is provided, but the power required for the pump p3 can be reduced.

Alternatively, the pressure recovery device 21 of the conventional direct pressure conversion method may be used to directly apply the pressure of the brine s6 to the UF membrane 3 . The structure of the sea water.

Further, the rotational kinetic energy (mechanical kinetic energy) or pressure energy recovered by the energy recovery device 21 may not be applied to the seawater flowing through the UF membrane 3, but may be applied to other places.

According to the second embodiment, the pressure energy of the brine s6 is recovered by the energy recovery device 21, so that energy saving can be achieved. Therefore, energy costs can be reduced.

Further, in the seawater desalination system 2S of the second embodiment, the case where the heat exchanger 6 is provided is exemplified, but in the zone where the temperature of the seawater is high, the structure of the heat exchanger 6 may not be provided. .

[Embodiment 3]

Fig. 5 is a conceptual configuration diagram of a seawater desalination system according to a third embodiment of the present invention.

The seawater desalination system 3S of the third embodiment is configured to merge the brine s6 separated by the low pressure RO membrane 2 of the seawater desalination system S of the first embodiment into the seawater flow path r2.

The other components are the same as those of the seawater desalination system S of the first embodiment. Therefore, the same components as those of the first embodiment are denoted by the same reference numerals, and the detailed description thereof will be omitted.

The seawater desalination system 3S collects the brine s6 separated by the low pressure RO membrane 2 into the seawater flow path r2, and uses the pressure energy of the brine s6 to obtain the pressure of the seawater toward the UF membrane 3. Therefore, a structure in which it is not necessary to set the pump p3 is employed.

In this case, the produced water s9 made from seawater is used as industrial water. In addition, the production water s9 can also be used as drinking water.

According to the seawater desalination system 3S of the third embodiment, since the pump p3 is not provided, it is possible to solve the problems such as the manufacturing cost of the pump p3, the installation cost, and the maintenance cost, and the cost is reduced.

Further, when the pressure energy of the brine s6 is not sufficiently large and the pressure transmitting force of the seawater to the UF film 3 is insufficient, the structure in which the pump p3 is provided may be changed. In this case, the power of the pump p3 can be reduced, so that energy saving can be achieved. Therefore, energy costs can be reduced.

In the seawater desalination system 3S of the third embodiment, the heat exchanger 6 is provided. However, in a zone where the temperature of the seawater is high, the heat exchanger 6 may not be provided.

[Other embodiments]

Further, in the first to third embodiments, although the domestic sewage and the seawater are separately desalinated to produce industrial water and drinking water, the present invention is also applicable to: domestic sewage and seawater. They are desalinated separately, but they do not produce drinking water and only produce industrial water. It is also applicable to, for example, the case where part of the domestic sewage of Fig. 7 flows into a path for desalinating seawater to produce industrial water.

Therefore, the present invention can be widely applied as long as it is a system for desalination of domestic sewage and seawater.

1‧‧‧MBR

2‧‧‧Low-pressure RO membrane (1RO membrane)

3‧‧‧UF film

5‧‧‧High pressure RO membrane (2RO membrane)

6, 6A, 6B, 6C‧‧ ‧ heat exchanger

21‧‧‧Energy recovery unit

S, 2S, 3S‧‧‧ seawater desalination system

S1‧‧‧Industrial water (treated water for domestic sewage)

S2‧‧‧ drinking water

s5a‧‧‧MBR through water (through water, domestic sewage treatment water)

S5b‧‧‧UF membrane through seawater (treated water)

S6‧‧‧ brine (the first concentrated water, domestic sewage treatment water)

S7‧‧‧ brine (2nd concentrated water)

Fig. 1 is a conceptual configuration diagram of a seawater desalination system according to Embodiment 1 of the present invention.

Fig. 2 is a conceptual diagram showing various combinations of heat exchangers in the seawater desalination system according to Embodiment 1 of the present invention, and Fig. 2(a) shows the flow of seawater to the flow path of domestic sewage for heat generation. Conceptual diagram of the exchanged heat exchanger; Figure 2(b) is a conceptual diagram showing a heat exchanger that delivers domestic sewage to the seawater flow path for heat exchange; Figure 2(c) shows the heat A conceptual diagram of a heat exchanger in which a medium stream is sent to a flow path of domestic sewage and a flow path of sea water for heat exchange.

Fig. 3 is a view showing a position where heat is exchanged for domestic sewage in the seawater desalination system according to the first embodiment of the present invention.

Fig. 4 is a conceptual configuration diagram of a seawater desalination system according to a second embodiment of the present invention.

Fig. 5 is a conceptual configuration diagram of a seawater desalination system according to a third embodiment of the present invention.

Figure 6 is a conceptual block diagram of a conventional desalination system.

Figure 7 is a conceptual block diagram of a conventional other type of desalination system.

1‧‧‧MBR

2‧‧‧Low-pressure RO film

3‧‧‧UF film

4‧‧‧Stirring tank

5‧‧‧High pressure RO membrane

6‧‧‧ heat exchanger

S‧‧‧Water desalination system (desalination system)

S1‧‧‧ industrial water

S2‧‧‧ drinking water

s5a‧‧‧MBR through water

S5b‧‧‧UF membrane through seawater

S6‧‧‧ brine

S7‧‧‧ brine

P1, p2, p3, p4‧‧ ‧ pump

The upstream flow path of r11‧‧‧MBR

Upstream flow path of r2‧‧‧UF membrane

Claims (9)

A seawater desalination system is a seawater desalination system that desalinates seawater and domestic sewage, and is characterized in that it includes a heat exchanger that exchanges heat between the domestic sewage or the treated water and the seawater. A seawater desalination system is a seawater desalination system that desalinates seawater and domestic sewage, and is characterized in that: the membrane separation activated sludge treatment device that treats the domestic sewage by membrane separation activated sludge method, has been worn The permeated water after the separation of the activated sludge treatment device through the membrane is passed through, and the salt is removed in the first concentrated water to be removed, and the first RO membrane of the industrial water is produced, and the seawater is passed through to the particles in the seawater. The UF film to be removed is passed through the treated water which has passed through the UF film, and the salt of the treated water is removed in the second concentrated water to be removed, and the second RO membrane of the drinking water is produced, and the domestic sewage or the aforementioned domestic sewage or It is a heat exchanger that treats heat exchange between water and the aforementioned seawater. The seawater desalination system according to claim 2, wherein the heat exchanger separates the seawater upstream of the UF membrane from the domestic sewage upstream of the activated sludge treatment device, or The permeated water after the membrane separation activated sludge treatment device has passed through, or the first concentrated water or the industrial water produced as described above Which kind of heat exchange. The seawater desalination system according to the second or third aspect of the invention, further comprising: an energy recovery device for recovering pressure energy of the first concentrated water. The seawater desalination system according to the second or third aspect of the invention, wherein the first concentrated water and the seawater upstream of the UF membrane are merged. A seawater desalination method is a seawater desalination method for desalinating seawater and domestic sewage, characterized in that the domestic sewage or the treated water in the desalination process of the domestic sewage is heat-exchanged with the seawater. A seawater desalination method is a seawater desalination method for desalinating seawater and domestic sewage, characterized in that: the domestic sewage or the treated water in the desalination process of the domestic sewage is exchanged with the seawater to make the domestic sewage The industrial water is generated by penetrating the membrane separation activated sludge treatment device and the first RO membrane, and the seawater is passed through the UF membrane and the second RO membrane to generate drinking water. The seawater desalination method according to claim 7, wherein the pressure energy of the first concentrated water removed by the first RO membrane is recovered. The seawater desalination method according to the seventh aspect of the invention, wherein the first concentrated water removed by the first RO membrane is condensed with the seawater upstream of the UF membrane.