JP2015107466A - Circulating water utilization system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a circulating water utilization system which can sufficiently utilize energy in the whole system, when a novel circulating water utilization system is investigated.SOLUTION: A circulating water utilization system 1 built for a specific region includes: a circulation passage 2 through which circulating water flows; a discharge passage 4 discharging discharge water discharged from a water demand body 3 to the circulation passage; a purifier 8 purifying the circulating water; a feeding passage 6 feeding the purified circulating water to a water demand body; methane fermentation equipment 10 making sludge cake generated with purification of the circulation water ferment; at least one among a first power generator 12 for burning methane to generate electricity and a second power generator 14 for burning methane fermentation residue to generate electricity; seawater desalination equipment 16 for desalinating seawater using electric power provided from the at least one; and a fresh water feed pipe 18 to feed the provided fresh water to the water demand body.

Description

  The present disclosure relates to a circulating water utilization system constructed for a specific area.

  In order to effectively use limited water resources, systems that purify and reuse waste water discharged from buildings and homes have been known. For example, Patent Document 1 discloses a wastewater reuse system that can be configured to use drainage of rainwater and rainwater used in general households as washing water for flush toilets and the like to save water. . Further, Patent Document 2 discloses a facility for planting greenery in a building that uses middle water to process miscellaneous wastewater generated in the building to generate middle water and reuse the generated middle water as irrigation water for plants cultivated in the building. Is disclosed.

JP-A-8-19773 Japanese Patent Laid-Open No. 10-286033 JP 2010-188344 A

By the way, the present applicant is studying a new circulating water utilization system that is completely different from the above-described conventional reuse system.
The above-mentioned conventional reuse system basically purifies the drainage of tap water supplied from the public water supply network in one building or one household, and uses it as intermediate water for specific purposes. The used municipal water is discharged into the sewer network. In other words, it is premised on the existence of an existing public water supply network and sewer network, and cannot be a system that replaces this.

  On the other hand, the new circulating water utilization system that the applicant is considering is small-scaled for areas and complex facilities where, for example, 10,000 people live, as will be described in detail later. This system provides integrated water and sewage treatment services, and water is supplied and treated in a cyclical manner within the area and building. In other words, this circulating water utilization system may adopt a configuration that receives a limited supply from the water supply, but is basically a small-scale distributed type constructed independently of the existing public water supply network and sewer network. It is an integrated water and sewage treatment system.

In considering such a new circulating water utilization system, as one of the water supply forms, a form in which seawater is desalinated and supplied to water consumers can be considered.
In Patent Document 3, in order to efficiently obtain fresh water in a seawater desalination apparatus, supernatant water obtained by precipitation separation of inorganic wastewater from a metal manufacturing plant such as steel is mixed with seawater as dilution water and diluted. It is described to do. However, since the above-described new circulating water utilization system is not assumed, a configuration for efficiently using energy in the entire circulating water utilization system including a device for desalinating seawater has been studied. Absent.

  The objective which concerns on at least 1 embodiment of this invention is providing the circulating water utilization system which can utilize energy efficiently in the whole system in examining a novel circulating water utilization system.

(1) Some embodiments of the present invention
A circulating water use system constructed for a specific area,
A circulation channel through which the circulating water flows;
Circulating the discharged water discharged from a water demand body composed of a plurality of small water demand bodies consisting of at least one of a residence, a tenant, and an office that uses the circulating water flowing through the circulation channel. A discharge flow path for discharging to the flow path;
A purification device for purifying the circulating water including the discharged water flowing through the circulation channel;
A supply flow path for supplying circulating water purified by the purification device to the water demand body;
A methane fermentation apparatus for methane fermentation of sludge cake generated along with purification of the circulating water by the purification apparatus;
At least one of a first power generation device that generates power by burning methane gas generated by the methane fermentation device, and a second power generation device that generates power by burning methane fermentation residue generated by the methane fermentation device;
A seawater desalination apparatus that desalinates seawater using electric power obtained from at least one of the first power generation apparatus and the second power generation apparatus;
A fresh water supply pipe for supplying fresh water generated by the seawater desalination apparatus to the water demand body;
Have

In the new circulating water utilization system examined by the present applicant, as one of the water supply forms, a form in which seawater is desalinated and supplied to water consumers can be considered. This form is a form that is more likely to be introduced, for example, when it is applied to an area adjacent to a desert where water supply is not yet developed.
When adopting a form in which seawater is desalinated and supplied to consumers as one of the forms of water supply in the new circulating water utilization system, it takes a lot of energy to desalinate seawater. It is desirable to reduce energy consumption in the entire system by efficiently using energy.
On the other hand, in the purification device of the circulating water utilization system, sludge cake is generated along with the purification of the circulating water including the discharged water discharged from the water consumer. When this sludge cake is subjected to methane fermentation, methane gas and methane fermentation residue are obtained. Therefore, at least one of the first power generation device that generates power by burning the methane gas and the second power generation device that generates power by burning the methane fermentation residue. It is possible to obtain electric power from the sludge cake.
Therefore, if the electric power obtained from at least one of the first power generation device and the second power generation device is used for seawater desalination, it is necessary for seawater desalination by the energy recovered from the discharged water in the circulating water utilization system. Can cover at least part of the energy. Thereby, since energy can be efficiently used in the entire circulating water utilization system, it is possible to effectively reduce energy consumption in the entire system.
In addition, as a seawater desalination method using a seawater desalination apparatus, various methods such as an evaporation method, an electrolysis method, and a reverse osmosis method can be used.

(2) In some embodiments, in the circulating water utilization system according to (1) above,
The seawater desalination apparatus is:
A pump that pressurizes the seawater using power obtained from at least one of the first power generation device and the second power generation device;
A reverse osmosis membrane for producing fresh water by filtering seawater pressurized by the pump;
Have

  In the circulating water utilization system described in (2), a method of filtering seawater pressurized by a pump through a reverse osmosis membrane is adopted, and the first power generation device and the second power generation are used as electric power for driving the pump. Electric power obtained from at least one of the devices is used. Therefore, at least a part of the pump drive energy for seawater desalination can be covered by the energy recovered from the discharged water in the circulating water utilization system described in (1) above. Thereby, since energy can be efficiently used in the entire circulating water utilization system, it is possible to effectively reduce energy consumption in the entire system.

(3) In some embodiments, in the circulating water utilization system according to (2) above,
A tank provided upstream of the pump and storing the seawater;
A pipe for dilution that connects the circulation channel and the tank, and dilutes the seawater in the tank using the circulating water from the circulation channel;
It has further.

When seawater is filtered through a reverse osmosis membrane to produce fresh water, the greater the difference between the salinity of the seawater and the salinity of the freshwater to be produced, the greater the pressure required for desalination. The required energy will also increase.
Therefore, in the circulating water utilization system described in (3), a dilution pipe that connects the tank upstream of the pump and the circulation channel is provided, and the seawater in the tank is diluted with the circulating water from the circulation channel. It is configured to do. As a result, the seawater can be diluted using the circulating water from the circulation channel, so the difference between the salinity of the seawater and the salinity to be generated is reduced, and the pressure required for desalination is reduced. can do. That is, the pump drive energy for seawater desalination can be reduced by utilizing the circulating water from the circulation channel.

(4) In some embodiments, in the circulating water utilization system according to any one of (1) to (3) above,
A flow meter for measuring the flow rate of the discharged water in the discharge channel;
A control unit that controls the seawater desalination device to increase the amount of freshwater generated in the seawater desalination device, as the flow rate of the discharged water measured by the flow meter is larger;
It has further.

  In the circulating water utilization system described in the above (1) to (3), the flow rate of the discharged water in the discharge channel increases as the water usage amount of the water consumer increases. Therefore, the flow rate of the discharged water in the discharge channel reflects the water demand of the water demanding body. Therefore, in the circulating water utilization system described in (4) above, a flow meter for measuring the flow rate of discharged water in the discharge channel is provided as described above, and the amount of fresh water generated in the seawater desalination apparatus increases as the flow rate increases. Have a lot. Thereby, with a simple configuration, an appropriate amount of fresh water can be generated according to the amount of water demand. Moreover, when providing the fresh water tank which stores the produced | generated fresh water in order to supply the appropriate amount of fresh water according to the fluctuation | variation of water demand timely, the tank capacity | capacitance can be made small.

(5) In some embodiments, in the circulating water utilization system according to (3) above,
A flow meter for measuring the flow rate of the discharged water in the discharge channel;
A valve for adjusting the flow rate of circulating water in the dilution pipe;
A control unit that controls to increase the amount of fresh water generated in the seawater desalination device as the flow rate of the discharged water measured by the flow meter increases.
Further comprising
The control unit controls the valve so that the flow rate of the circulating water in the dilution pipe increases as the flow rate of the discharged water measured by the flow meter increases.

In the circulating water utilization system described in (3) above, the greater the amount of water used by the water consumer, the greater the flow rate of the discharged water in the discharge channel. Therefore, the flow rate of the discharged water in the discharge channel reflects the water demand of the water demanding body. Therefore, in the circulating water utilization system described in (5) above, a flow meter for measuring the flow rate of the discharged water in the discharge channel is provided as described above, and the amount of fresh water generated in the seawater desalination device increases as the flow rate increases. Have a lot. Thereby, with a simple configuration, an appropriate amount of fresh water can be generated according to the amount of water demand. Therefore, when providing a fresh water tank for storing the generated fresh water in order to supply an appropriate amount of fresh water according to the fluctuation of the water demand in a timely manner, the tank capacity can be reduced.
Moreover, by controlling the valve of the dilution pipe so that the flow rate of the circulating water in the dilution pipe increases as the flow rate of the discharged water increases, an appropriate amount of fresh water is generated according to the water demand, and the seawater fresh water It is possible to reduce the pump drive energy for the conversion.

(6) In some embodiments, in the circulating water utilization system according to any one of (1) to (5) above,
The circulating water utilization system has at least the first power generation device among the first power generation device and the second power generation device,
The first power generation device includes a gas engine for burning the methane gas, and a first generator driven by the gas engine,
The circulating water utilization system is:
A first condensing economizer that heats the heat medium using the latent heat of condensation of the exhaust gas discharged from the gas engine;
A first condensed water supply pipe for supplying condensed water generated in the first condensed economizer to the water demand body;
It has further.

In the circulating water utilization system described in (6) above, the sludge cake generated with the purification of the circulating water is subjected to methane fermentation, and the generated methane gas is burned by the gas engine to drive the first generator.
Further, the first condensing economizer that heats the heat medium using the latent heat of condensation of the exhaust gas discharged when the methane gas is burned by the gas engine, and the condensed water generated by the first condensing economizer to the water consumer Since it has the 1st condensed water supply pipe for supplying, the condensed water which generate | occur | produced in the 1st condensation economizer is effectively utilized within a circulating water utilization system, collect | recovering the thermal energy of the exhaust gas accompanying combustion of methane gas be able to.
In addition, the heat medium heated with the 1st condensation economizer can be utilized for the hot water supply and heating in a water demand body, for example. Moreover, in order to supply condensed water to a water demand body with a 1st condensed water supply pipe | tube, you may perform pH adjustment, purification | cleaning, etc. suitably with respect to condensed water. For example, if condensed water is replenished as make-up water at a position upstream of the purification device in the circulation flow path or in the discharge flow path, the water demand body can be supplied after purification by the purification apparatus. In addition, if condensed water is supplied as dilution water to the tank or the dilution pipe described in (3), the driving energy of the pump can be reduced.

(7) In some embodiments, in the circulating water utilization system according to (6) above,
In order to raise the temperature of the seawater before desalination in the reverse osmosis membrane, the apparatus further includes a seawater temperature raising transfer pipe for transferring the heat medium heated by the first condensation economizer from the first condensation economizer.
According to the circulating water utilization system described in the above (7), the temperature of the seawater is raised by using the heat medium heated by the first condensation economizer, so that the viscosity of the seawater decreases. The required drive energy of the pump can be reduced. Moreover, it can also use for the improvement of the seawater desalination apparatus (water production capacity).

(8) In some embodiments, in the circulating water utilization system according to (6) or (7) above,
A circulating water heating transfer pipe for transferring the heat medium heated by the first condensing economizer from the first condensing economizer to raise the temperature of the circulating water upstream of the purification device in the circulation channel. Is further provided.

  According to the circulating water utilization system described in (8) above, the circulating water in the purification device is heated by heating the upstream side of the purification device using the heat medium heated by the first condensing economizer. The drive energy of the pump used for the purification of can be reduced.

(9) In some embodiments, in the circulating water utilization system according to any one of (1) to (5) above,
The circulating water utilization system has at least the first power generation device among the first power generation device and the second power generation device,
The first power generator is a fuel cell that generates power using the methane gas,
The circulating water utilization system further includes a generated water supply pipe for supplying generated water generated by the fuel cell to the water demand body.

In the circulating water utilization system described in (9) above, the sludge cake generated along with the purification of the circulating water is subjected to methane fermentation, and electric power is obtained from the fuel cell using the generated methane gas. At this time, a solid oxide fuel cell (SOFC) that can directly use methane gas may be used, and the methane gas is reformed into hydrogen by a steam reforming method, a partial oxidation method, or the like. You may use the fuel cell using.
According to the circulating water utilization system described in (9) above, since the generated water supply pipe for supplying the generated water generated in the fuel cell to the water consumer is provided, the generated water generated in the fuel cell Can be effectively utilized in the circulating water utilization system.
In addition, in order to supply the generated water to the water consumer through the generated water supply pipe, PH adjustment, purification, and the like may be appropriately performed on the generated water. For example, if the generated water is replenished as make-up water at a position upstream of the purification device in the circulation flow path or in the discharge flow path, it can be supplied to the water consumer after purification by the purification apparatus. Further, if the generated water is supplied as dilution water to the tank or the dilution pipe described in (3), it is possible to reduce the driving energy of the pump.

(10) In some embodiments, in the circulating water utilization system according to any one of (1) to (9) above,
The circulating water utilization system has at least the second power generation device among the first power generation device and the second power generation device,
The second power generation device includes a boiler that burns methane fermentation residue generated by the methane fermentation device, a steam turbine driven by steam generated in the boiler, a second generator driven by the steam turbine,
Have
The circulating water utilization system is:
A second condensing economizer that heats the heat medium using the latent heat of condensation of the exhaust gas discharged from the boiler;
A second condensed water supply pipe for supplying condensed water generated by the second condensed economizer to the water demand body;
It has further.

In the circulating water utilization system described in the above (10), the sludge cake generated along with the purification of the circulating water is subjected to methane fermentation, and the generated methane fermentation residue is combusted by a boiler to generate steam, via a steam turbine. The second generator is driven.
In addition, the second condensing economizer that heats the heat medium using the condensation latent heat of the exhaust gas discharged when the methane fermentation residue is burned in the boiler, and the condensed water generated in the second condensing economizer A second condensate supply pipe for supplying to the exhaust gas, so that the condensed water generated in the second condensing economizer is recovered in the circulating water utilization system while recovering the thermal energy of the exhaust gas accompanying the combustion of the methane fermentation residue. It can be used effectively.
In addition, the heat medium heated with the 2nd condensation economizer can be utilized for the hot water supply and heating in a water demand body, for example. Moreover, in order to supply condensed water to a water demand body with a 2nd condensed water supply pipe, you may perform PH adjustment, purification | cleaning, etc. suitably with respect to condensed water. For example, if condensed water is replenished as make-up water at a position upstream of the purification device in the circulation flow path or in the discharge flow path, the water demand body can be supplied after purification by the purification apparatus. In addition, if condensed water is supplied as dilution water to the tank or the dilution pipe described in (3), the driving energy of the pump can be reduced.

(11) In some embodiments, in the circulating water utilization system according to (10) above,
In order to raise the temperature of the seawater before desalination in the reverse osmosis membrane, a heating medium transfer pipe for raising the temperature of seawater that transfers the heating medium heated by the second condensation economizer from the second condensation economizer In addition.

  According to the circulating water utilization system described in (11) above, the temperature of the seawater is raised by using the heat medium heated by the second condensation economizer, so that the viscosity of the seawater decreases. The required drive energy of the pump can be reduced. Moreover, it can also use for the improvement of the seawater desalination apparatus (water production capacity).

(12) In some embodiments, in the circulating water utilization system according to (10) or (11) above,
In order to raise the temperature of the circulating water upstream of the purification device in the circulation flow path, the transfer pipe for raising the circulating water temperature for transferring the heat medium heated by the second condensation economizer from the second condensation economizer Is further provided.

  According to the circulating water utilization system described in (12) above, the circulating water in the purification device is heated by heating the upstream side of the purification device using the heat medium heated by the second condensation economizer. The drive energy of the pump used for the purification of can be reduced.

(13) In some embodiments, in the circulating water utilization system according to any one of (1) to (12) above,
It further has a condensed water recovery pipe for recovering the condensed water discharged from the air-conditioning equipment used in the water consumer and using it in the water consumer.

Thereby, the condensed water discharged | emitted from the air-conditioning equipment used with the said water demand body can be effectively utilized within a circulating water utilization system.
Moreover, in order to supply condensed water to a water demand body with a condensed water collection pipe, you may perform PH adjustment, purification | cleaning, etc. suitably with respect to condensed water. For example, if condensed water is replenished as make-up water at a position upstream of the purification device in the circulation flow path or in the discharge flow path, the water demand body can be supplied after purification by the purification apparatus. In addition, if condensed water is supplied as dilution water to the tank or the dilution pipe described in (3), the driving energy of the pump can be reduced.

  According to at least one embodiment of the present invention, in considering a new circulating water utilization system, it is possible to provide a circulating water utilization system that can efficiently use energy in the entire system.

It is the whole schematic diagram which showed the circulating water utilization system concerning some embodiment. It is a figure which shows the specific structural example of the 1st electric power generating apparatus which concerns on some embodiment. It is a figure which shows the specific structural example of the 1st electric power generating apparatus which concerns on some embodiment. It is a figure which shows the specific structural example of the 2nd electric power generating apparatus which concerns on some embodiment. It is a figure which shows the specific structural example of the purification | cleaning means which concerns on some embodiment.

Hereinafter, embodiments of the present invention will be described in more detail based on the drawings.
However, the scope of the present invention is not limited to the following embodiments. The dimensions, materials, shapes, relative arrangements, and the like of the component parts described in the following embodiments are not merely intended to limit the scope of the present invention, but are merely illustrative examples.

FIG. 1 is an overall schematic diagram showing a circulating water utilization system according to some embodiments of the present invention.
The circulating water utilization system 1 is a system constructed for a specific area separately from the public water supply network. The population scale targeted by this system is assumed to be approximately 5,000 to 20,000. The target area includes a condominium that is a collection of residences, an office building that is a collection of offices, a commercial facility that is a collection of tenants, and a complex facility in which these are mixed.

  As shown in FIG. 1, the circulating water utilization system 1 includes a circulation flow path 2, a water demand body 3, a discharge flow path 4, a supply flow path 6, a purification means 8 (purification apparatus), a methane fermentation apparatus 10, a first The power generation device 12, the second power generation device 14, a seawater desalination device 16, a fresh water supply pipe 18, and the like.

  The circulation channel 2 is configured as a pipe network in which water pipes are arranged in a closed loop shape. Devices such as a pump (not shown) and a valve (not shown) are appropriately arranged in the circulation channel 2 according to the terrain conditions so that the circulating water circulates in one direction.

  The water consumer 3 is a main body that uses the circulating water flowing through the circulation channel 2 as domestic water. The water demanding body 3 is constituted by a plurality of small water demanding bodies consisting of at least one of the residence 3a, the tenant 3b, and the office 3c. The dwelling 3a refers to a room in a condominium where one household lives or a detached house. The tenant 3b refers to a store that provides services to general customers in a section of a commercial facility. The business types include, for example, retail stores such as clothing stores, general stores, drug stores, liquor stores, and restaurants, restaurants, cafes, sushi restaurants, taverns, and the like. The office 3c refers to a place where a worker who works in a part of an office building performs office work for a certain purpose.

  Examples of the use of domestic water in the residence 3a include potable water, showers and baths, laundry, dish washing, hand washing and face washing, toilets, and the like. Examples of uses of domestic water in the tenant 3b include potable water, washing, and toilets. Moreover, the amount of water demand varies greatly depending on the type of industry. For example, restaurants use a much larger amount of domestic water than retailers. The use of domestic water in the office 3c is mainly potable water and toilets.

  The discharge channel 4 is a channel for draining the drain water discharged from the water consumer 3 to the circulation channel 2. The discharged water discharged from the discharge flow path 4 includes fresh water generated from seawater by the seawater desalination device 16 and other water derived from outside the system, in addition to circulating water used by the water consumer 3 as domestic water. Is also included.

  The purification means 8 (purification device) is a means for purifying the circulating water including the discharged water flowing through the circulation flow path 2.

  The supply flow path 6 is a flow path for supplying the circulating water purified by the purification means 8 to the water consumer 3 as domestic water. Both the discharge flow path 4 and the supply flow path 6 are constituted by pipe lines. Further, the discharge channel 4 and the supply channel 6 are appropriately set according to the terrain conditions so that the discharged water is drained into the circulation channel 2 or the circulating water is supplied to the water demanding body 3. Devices such as a pump (not shown) and a valve (not shown) are arranged.

  The methane fermentation apparatus 10 is configured to perform methane fermentation of the sludge cake generated with the purification of the circulating water by the purification means 8.

  The first power generation device 12 is configured to generate power by burning the methane gas generated by the methane fermentation device 10, and the second power generation device 14 is configured to generate power by burning the methane fermentation residue generated by the methane fermentation device 10. . In addition, although the exemplary circulating water utilization system 1 shown in FIG. 1 has both the 1st electric power generating apparatus 12 and the 2nd electric power generating apparatus 14, it should just have not only this but at least one.

  The seawater desalination apparatus 16 is configured to desalinate seawater using the power 120 obtained from the first power generation apparatus 12 and the power 140 obtained from the second power generation apparatus 14, and is generated by the seawater desalination apparatus 16. The fresh water thus obtained is supplied to the water consumer as fresh water by the fresh water supply pipe 18 (18a, 18b), or purified to the same quality as commercially available mineral water and used as drinking water. In the middle of the fresh water supply pipe 18, a fresh water tank 29 for storing fresh water generated by the seawater desalination apparatus 16 may be provided in order to cope with fluctuations in the water demand of the water demanding body 3. Various methods such as an evaporation method, an electrolysis method, and a reverse osmosis method can be used as a method of seawater desalination by the seawater desalination apparatus 16.

  As shown in FIG. 1, the seawater desalination apparatus 16 according to some embodiments includes a pump 20 that pressurizes seawater using electric power 120 and 140, and a seawater that is pressurized by the pump 20 by filtering the seawater. A reverse osmosis membrane 22 for generating The exemplary circulating water utilization system 1 shown in FIG. 1 is configured to desalinate seawater using the electric power 120 obtained from the first power generation device 12 and the electric power 140 obtained from the second power generation device 14. However, the present invention is not limited to this, and it may be configured to desalinate seawater using electric power from at least one.

  As described above, in the purification device 8 of the circulating water utilization system 1, sludge cake is generated along with the purification of the circulating water including the discharged water discharged from the water demanding body 3. When this sludge cake is subjected to methane fermentation in the methane fermentation apparatus 10, methane gas and methane fermentation residue are obtained. Therefore, the first power generation apparatus 12 that generates electricity by burning this methane gas, and the second that generates electricity by burning the methane fermentation residue. By providing at least one of the power generation devices 14, electric power can be obtained from the sludge cake.

  Therefore, if the electric power obtained from at least one of the first power generation device 12 and the second power generation device 14 is used for the seawater desalination device 16, the energy recovered from the discharged water in the circulating water utilization system 1 can be used for desalination of seawater. To provide at least part of the energy required for Thereby, since energy can be efficiently used by the circulating water utilization system 1 whole, it becomes possible to reduce the energy consumption in the whole system effectively.

  In some embodiments, the circulating water utilization system 1 may include a seawater tank 24 and a dilution pipe 26 as shown in FIG. The seawater tank 24 is provided on the upstream side of the pump 20 and configured to store seawater. The dilution pipe 26 connects the circulation channel 2 and the seawater tank 24, and is configured to dilute the seawater in the seawater tank 24 using the circulation water from the circulation channel 2.

  When fresh water is generated by filtering seawater through the reverse osmosis membrane 22, the greater the difference between the salt concentration of sea water and the salt concentration of fresh water to be generated, the greater the pressure required for desalination. The energy required for driving also increases.

  Therefore, in the circulating water utilization system 1 shown in FIG. 1, as described above, the dilution pipe 26 that connects the seawater tank 24 on the upstream side of the pump 20 and the circulation flow path 2 is provided, and the seawater in the seawater tank 24 is circulated. It is configured to dilute using circulating water from the flow path 2. As a result, the seawater can be diluted by utilizing the circulating water from the circulation flow path 2, so the difference between the salinity concentration of the seawater and the salinity concentration to be generated is reduced, and the pressure required for desalination is reduced. Can be small. That is, the driving energy of the pump 20 for seawater desalination can be reduced by utilizing the circulating water from the circulation channel 2.

  In some embodiments, the circulating water utilization system 1 may include a flow meter 27 and a control unit 70 as shown in FIG. In this case, the flow meter 27 is configured to measure the flow rate of the discharged water in the discharge channel 4, and the control unit 70 increases the flow rate of the discharged water measured by the flow meter 27 in the seawater desalination apparatus 16. Control to increase the amount of fresh water produced.

  The greater the amount of water used by the water demanding body 3, the greater the flow rate of the discharged water in the discharge flow path 4, so the flow rate of the discharged water in the discharge flow path 4 reflects the water demand of the water demanding body 3. Therefore, as described above, the flow meter 27 for measuring the flow rate of the discharged water in the discharge flow path 4 is provided, and the amount of fresh water generated in the seawater desalination apparatus 16 is increased as the flow rate increases. Thereby, an appropriate quantity of fresh water can be produced | generated with a simple structure according to the water demand of a water consumer. Therefore, when providing the fresh water tank 29 which stores the produced | generated fresh water in order to supply the appropriate amount of fresh water according to the fluctuation | variation of water demand timely, the capacity | capacitance of the fresh water tank 29 can be made small.

  The control unit 70 controls the flow rate adjustment valve 31 provided in the dilution pipe 26 to increase the flow rate of the circulating water in the dilution pipe 26 (seawater tank) as the flow rate of the discharged water measured by the flow meter 27 increases. (Supply amount of dilution water to 24) is increased. Thereby, while producing | generating an appropriate amount of fresh water according to a water demand, the pump drive energy for seawater desalination can be reduced.

  FIG. 2 is a specific configuration example of the first power generation device 12 according to some embodiments. As shown in FIG. 2, in some embodiments, the first power generator 12 includes a gas engine 28 that combusts methane gas and a first generator 30 that is driven by the gas engine 28. In this case, the circulating water utilization system 1 uses the first condensation economizer 32 that heats the heat medium using the condensation latent heat of the exhaust gas discharged from the gas engine 28, and the condensed water generated by the first condensation economizer 32. You may have with the 1st condensed water supply pipe 34 for supplying to the water consumer 3. Thereby, the condensed water generated in the first condensation economizer 32 can be effectively utilized in the circulating water utilization system 1 while recovering the thermal energy of the exhaust gas accompanying the combustion of the methane gas.

In addition, the heat medium heated with the 1st condensation economizer 32 can be utilized for the hot water supply and heating in the water demand body 3, for example. Further, the heat medium may be used for raising the temperature of seawater before being desalinated in the reverse osmosis membrane 22. In this case, as shown in FIG. 2, a heat medium transfer pipe 35 for raising the temperature of seawater for transferring the heat medium heated by the first condensing economizer 32 from the first condensing economizer 32 is provided. Since the viscosity of the seawater is lowered by raising the temperature, the driving energy of the pump 20 necessary for water permeation of the reverse osmosis membrane 22 can be reduced. In addition, the seawater desalination apparatus 16 can be used to improve the water production capacity (water production). In addition, you may comprise so that the temperature of circulating water may be heated in the circulation flow path 2 upstream of the purification apparatus 8, and the drive energy of the pump which is not illustrated arrange | positioned for purification | cleaning of circulating water may be reduced. In this case, as shown in FIG. 2, a heat medium transfer pipe 37 for raising the circulating water temperature for transferring the heat medium heated by the first condensing economizer 32 from the first condensing economizer 32 is provided.
Moreover, in order to supply condensed water to the water demand body 3 with the 1st condensed water supply pipe 34, you may perform PH adjustment, purification | cleaning, etc. with respect to condensed water suitably. For example, if condensed water is replenished as make-up water at a position upstream of the purification device 8 in the circulation flow path 2 or the discharge flow path 4, it is supplied to the water consumer 3 after purification by the purification device 8. can do. Further, if condensed water is supplied as dilution water to the seawater tank 24, dilution pipe 26, etc. in FIG. 1, the drive energy of the pump 20 can be reduced.

  FIG. 3 is a specific configuration example of the first power generation device 12 according to another embodiment. As shown in FIG. 3, in another embodiment, the first power generator 12 is a fuel cell 36 that generates power using methane gas. In this case, the circulating water utilization system 1 may have a generated water supply pipe 38 for supplying the generated water generated by the fuel cell 36 to the water consumer 3. Thereby, the generated water generated in the fuel cell 36 can be effectively used in the circulating water utilization system 1.

  In addition, in order to supply generated water to the water demand body 3 with the generated water supply pipe 38, PH adjustment, purification, etc. may be appropriately performed on the generated water. For example, if the generated water is replenished as make-up water at a position upstream of the purification device 8 in the circulation flow path 2 or the discharge flow path 4, the water is supplied to the water consumer 3 after purification by the purification device 8. can do. Further, if the generated water is supplied as dilution water to the seawater tank 24 and the dilution pipe 26 in FIG. 1, the driving energy of the pump 20 can be reduced.

  FIG. 4 is a specific configuration example of the second power generation device 14 according to some embodiments. As shown in FIG. 4, in some embodiments, the second power generation device 14 includes a boiler 40 that burns methane fermentation residue generated by the methane fermentation device 10, and a steam turbine 42 that is driven by steam generated in the boiler 40. And a second generator 44 driven by the steam turbine 42. In this case, the circulating water utilization system 1 uses the second condensation economizer 46 that heats the heat medium using the condensation latent heat of the exhaust gas discharged from the boiler 40, and the condensed water generated by the second condensation economizer 46 as water. You may have the 2nd condensed water supply pipe 48 for supplying to a demand body. Thereby, the condensed water generated in the second condensation economizer 46 can be effectively used in the circulating water utilization system while recovering the thermal energy of the exhaust gas accompanying the combustion of the methane fermentation residue.

  The heat medium heated by the second condensation economizer 46 can be used for hot water supply or heating in the water demanding body 3, for example. Further, the heat medium may be used for raising the temperature of seawater before being desalinated in the reverse osmosis membrane 22. In this case, as shown in FIG. 4, a heat medium transfer pipe 49 for raising the temperature of seawater for transferring the heat medium heated by the second condensing economizer 46 from the second condensing economizer 46 is provided. Since the viscosity of the seawater is lowered by raising the temperature, the driving energy of the pump 20 necessary for water permeation of the reverse osmosis membrane 22 can be reduced. In addition, the seawater desalination apparatus 16 can be used to improve the water production capacity (water production). In addition, you may comprise so that the temperature of circulating water may be heated in the circulation flow path 2 upstream of the purification apparatus 8, and the drive energy of the pump which is not illustrated arrange | positioned for purification | cleaning of circulating water may be reduced. In this case, as shown in FIG. 4, a heat medium transfer pipe 51 for raising the circulating water temperature for transferring the heat medium heated by the second condensing economizer 46 from the second condensing economizer 46 is provided. Moreover, in order to supply condensed water to the water demand body 3 with the 2nd condensed water supply pipe 48, you may perform PH adjustment, purification | cleaning, etc. with respect to condensed water suitably. For example, if condensed water is replenished as make-up water at a position upstream of the purification device 8 in the circulation flow path 2 or the discharge flow path 4, it is supplied to the water consumer 3 after purification by the purification device 8. can do. Further, if condensed water is supplied as dilution water to the seawater tank 24, dilution pipe 26, etc. in FIG. 1, the drive energy of the pump 20 can be reduced.

  As shown in FIG. 1, the circulating water utilization system 1 according to some embodiments collects condensed water discharged from an air conditioning facility 50 used in the water demand body 3 and uses it in the water demand body 3. Condensate recovery pipe 52 is provided. Thereby, the condensed water discharged | emitted from the air conditioning equipment 50 used with the water demand body 3 can be effectively utilized in the circulating water utilization system 1. FIG.

  Further, in order to supply the condensed water to the water consumer through the condensed water recovery pipe 52, the condensed water may be subjected to pH adjustment, purification, and the like as appropriate. For example, if condensed water is supplied as make-up water to a position upstream of the purification device 8 in the circulation flow path 2 or to the discharge flow path 4, the purification is performed by the purification device 8 and then supplied to the water consumer 3 can do. Further, if condensed water is supplied as dilution water to the seawater tank 24, dilution pipe 26, etc. in FIG. 1, the drive energy of the pump 20 can be reduced.

  FIG. 5 is a specific configuration example of the purifying unit 8 according to some embodiments. The purification means 8 uses a container-type treatment tank in which a treatment apparatus that performs one treatment step among a series of purification steps is stored inside the container. And it is comprised by connecting this container type processing tank in series along the order of a process process. In the embodiment shown in FIG. 5, the purification means 8 includes a screen / flow rate adjusting container L1, an anaerobic container L2, an aerobic container L3, a coarse film container L4, a fine film container L5, an ozone treatment container L6, and a water storage sterilization container L7. The sterilization container L8 is configured by being connected in series in this order.

  The screen / flow rate adjusting container L1 is a treatment tank that removes the inspection and oil contained in the discharged water, and includes equipment such as an oil trap and a screen device. The anaerobic container L2 and the aerobic container L3 are treatment tanks for performing anaerobic treatment and aerobic treatment to remove organic substances contained in the discharged water. As the treatment method, various known treatment methods such as A20 activated sludge method, batch activated sludge method, contact oxidation method, oxidation ditch method and the like can be adopted. The coarse film container L4 is a treatment tank for separating sludge from the discharged water. Various apparatuses and methods such as a precipitation tank, MF membrane, UF membrane, and centrifugal separation can be employed. The fine membrane container L5 is a treatment tank for increasing the quality of the circulating water to the level of water supply. Various devices and methods such as reverse osmosis membrane, activated carbon, sand filtration, ozone generator, ion exchange, and mineral addition device can be employed. The ozone treatment container L6 is a treatment tank for performing ozone treatment on the purified circulating water. The water storage sterilization container L7 is a treatment tank for temporarily storing the purified circulating water while storing and sterilizing the water with ultraviolet rays. The sterilization container L8 is a treatment tank for sterilizing and purifying the purified circulating water with ultraviolet rays, chlorine, ozone, or the like.

  The sludge return / sludge dewatering container L9 is a treatment tank for dewatering and drying sludge. The sludge storage containers L10 and L11 are treatment tanks for storing sludge cake. The sludge cake stored in the sludge storage containers L10 and L11 is supplied to the methane fermentation apparatus 10 shown in FIG.

  In addition, arrangement | positioning and a structure of the processing tank of the purification | cleaning means 8 mentioned above are examples, and can be variously changed according to the water quality of the waste_water | drain discharged | emitted, and the target purification level. Moreover, the code | symbol TW in a figure has shown the flow of the tap water supplied from a public water supply network. Thus, you may comprise so that the supplementary water from the outside of a system may be supplied also to the circulation flow path 2 as needed. The supply position in this case is preferably on the downstream side of the fine membrane container L5 where the purification process of the discharged water is almost completed. Moreover, the code | symbol WW4 in a figure is a return pipeline for sending concentrated water to the screen / flow control container L1.

  Thus, in the new circulating water utilization system 1 which the present applicant is examining, as the purification means 8 for purifying the discharged water, one treatment process in which a series of purification processes is divided into three or more treatment processes is performed. A container-type processing tank in which a processing apparatus to be performed is stored inside a container is used. Then, a container-type processing tank that performs the first processing step, a container-type processing tank that performs the next processing step, and a container-type processing tank that performs the subsequent processing steps are brought into the field, and each is connected in series with a connecting pipe. The purifying means 8 is constructed by connecting to. Such a container-type treatment tank is excellent in portability because it can be loaded and transported on a truck as it is. Moreover, since it is detachably accommodated in the container container, it can be installed and removed freely.

  The processing capacity per processing tank of the container-type processing tank is assumed to be a scale capable of processing about 1,000 people of discharged water. For this reason, for example, when this circulating water utilization system is introduced to an area or complex facility where 10,000 people live, a plurality of (for example, 10) treatment tanks that perform the same treatment process are required. Become. Thus, by providing a plurality of processing tanks that perform the same processing step, the processing capacity per processing tank can be reduced. Therefore, it is possible to flexibly cope with population fluctuations and water demand seasonal fluctuations in the target area. Moreover, it is easy to prepare an alternative processing tank, and the maintenance is excellent.

  As mentioned above, although the preferable form of this invention was demonstrated, this invention is not limited to said form. For example, the above-described embodiments may be combined, and various modifications can be made without departing from the object of the present invention.

  At least one embodiment of the present invention can be suitably used in a circulating water utilization system constructed for a specific area separately from a public water supply network.

DESCRIPTION OF SYMBOLS 1 Circulating water utilization system 2 Circulating flow path 3 Water demand body 3a Residential 3b Tenant 3c Office 4 Discharge flow path 6 Supply flow path 8 Purification means 10 Methane fermentation apparatus 12 1st power generation apparatus 14 2nd power generation apparatus 16 Seawater desalination apparatus 18 Fresh water supply pipe 20 Pump 22 Reverse osmosis membrane 24 Seawater tank 26 Dilution pipe 27 Flow meter 28 Gas engine 29 Fresh water tank 30 First generator 31 Flow rate adjustment valve 32 First condensation economizer 34 First condensed water supply pipe 36 Fuel cell 38 Generated water supply pipe 40 Boiler 42 Steam turbine 44 Second generator 46 Second condensing economizer 48 Second condensed water supply pipe 50 Air conditioning equipment 52 Condensed water recovery pipe 70 Control units 120 and 140 Electric power

Claims (13)

A circulating water utilization system,
A circulation channel through which the circulating water flows;
Circulating the discharged water discharged from a water demand body composed of a plurality of small water demand bodies consisting of at least one of a residence, a tenant, and an office that uses the circulating water flowing through the circulation channel. A discharge flow path for discharging to the flow path;
A purification device for purifying the circulating water including the discharged water flowing through the circulation channel;
A supply flow path for supplying circulating water purified by the purification device to the water demand body;
A methane fermentation apparatus for methane fermentation of sludge cake generated along with purification of the circulating water by the purification apparatus;
At least one of a first power generation device that generates power by burning methane gas generated by the methane fermentation device, and a second power generation device that generates power by burning methane fermentation residue generated by the methane fermentation device;
A seawater desalination apparatus that desalinates seawater using electric power obtained from at least one of the first power generation apparatus and the second power generation apparatus;
A fresh water supply pipe for supplying fresh water generated by the seawater desalination apparatus to the water demand body;
A circulating water utilization system. The seawater desalination apparatus is:
A pump that pressurizes the seawater using power obtained from at least one of the first power generation device and the second power generation device;
A reverse osmosis membrane for producing fresh water by filtering seawater pressurized by the pump;
The circulating water utilization system of Claim 1 which has these. A tank provided upstream of the pump and storing the seawater;
A pipe for dilution that connects the circulation channel and the tank, and dilutes the seawater in the tank using the circulating water from the circulation channel;
The circulating water utilization system according to claim 2, further comprising: A flow meter for measuring the flow rate of the discharged water in the discharge channel;
A control unit that controls the seawater desalination device to increase the amount of freshwater generated in the seawater desalination device, as the flow rate of the discharged water measured by the flow meter is larger;
The circulating water utilization system according to any one of claims 1 to 3, further comprising: A flow meter for measuring the flow rate of the discharged water in the discharge channel;
A valve for adjusting the flow rate of circulating water in the dilution pipe;
A control unit that controls to increase the amount of fresh water generated in the seawater desalination device as the flow rate of the discharged water measured by the flow meter increases.
Further comprising
The circulating water utilization system according to claim 3, wherein the control unit controls the valve so that the flow rate of the circulating water in the dilution pipe increases as the flow rate of the discharged water measured by the flow meter increases. . The circulating water utilization system has at least the first power generation device among the first power generation device and the second power generation device,
The first power generation device includes a gas engine for burning the methane gas, and a first generator driven by the gas engine,
The circulating water utilization system is:
A first condensing economizer that heats the heat medium using the latent heat of condensation of the exhaust gas discharged from the gas engine;
A first condensed water supply pipe for supplying condensed water generated in the first condensed economizer to the water demand body;
The circulating water utilization system according to any one of claims 1 to 5, further comprising:   In order to raise the temperature of the seawater before desalination in the reverse osmosis membrane, a heating medium transfer pipe for raising the temperature of seawater that transfers the heating medium heated by the first condensation economizer from the first condensation economizer The circulating water utilization system according to claim 6 further provided.   Heat for raising the circulating water temperature for transferring the heating medium heated by the first condensing economizer from the first condensing economizer in order to raise the temperature of the circulating water upstream of the purification device in the circulation channel. The circulating water utilization system according to claim 6 or 7, further comprising a medium transfer pipe. The circulating water utilization system has at least the first power generation device among the first power generation device and the second power generation device,
The first power generator is a fuel cell that generates power using the methane gas,
The circulating water utilization system according to any one of claims 1 to 5, further comprising a generated water supply pipe for supplying generated water generated by the fuel cell to the water demand body. . The circulating water utilization system has at least the second power generation device among the first power generation device and the second power generation device,
The second power generation device includes a boiler that burns methane fermentation residue generated by the methane fermentation device, a steam turbine driven by steam generated in the boiler, a second generator driven by the steam turbine,
Have
The circulating water utilization system is:
A second condensing economizer that heats the heat medium using the latent heat of condensation of the exhaust gas discharged from the boiler;
A second condensed water supply pipe for supplying condensed water generated by the second condensed economizer to the water demand body;
The circulating water utilization system according to any one of claims 1 to 9, further comprising:   In order to raise the temperature of the seawater before desalination in the reverse osmosis membrane, a heating medium transfer pipe for raising the temperature of seawater that transfers the heating medium heated by the second condensation economizer from the second condensation economizer The circulating water utilization system according to claim 10 further provided.   Heat for raising the circulating water temperature for transferring the heat medium heated by the second condensing economizer from the second condensing economizer to raise the temperature of the circulating water upstream of the purification device in the circulation channel. The circulating water utilization system according to claim 10 or 11, further comprising a medium transfer pipe.   The condensed water recovery pipe | tube for collect | recovering the condensed water discharged | emitted from the air-conditioning equipment used with the said water demand body, and using it with the said water demand body is any one of Claims 1-12 Circulating water utilization system.

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