JP6339359B2 - Wastewater utilization system and wastewater utilization method - Google Patents

Description

  The present invention relates to drainage utilization technology.

  Conventionally, there are facilities such as production factories and large-sized hot bath facilities that always discharge wastewater with waste heat. For example, warm water used for washing raw materials and containers is discharged from factories that produce and process food.

  In such facilities and nearby facilities, there may be a demand for hot water having an appropriate water quality for cleaning and the like. Conventionally, such hot water has been produced by heating water newly received from a water supply or the like with a boiler using fuel such as gas.

  In addition, in such facilities and nearby facilities, there may be demand for cooling for air conditioning and the like. For example, in a water-cooled air conditioning facility, there is a demand for cold heat for circulating and supplying cold water to an air conditioner. In such an air conditioning facility, cold water is supplied by cooling using a refrigerator that consumes electric power.

  Conventionally, a heat pump system for wastewater treatment facilities using a biological treatment method has been proposed as a technique for treating wastewater (see, for example, Patent Document 1). In addition, techniques for effectively using waste heat have been proposed (see, for example, Patent Documents 2 to 4).

JP 2012-115813 A JP 2011-149562 A JP 2007-202446 A Japanese Patent Publication No. 7-4212

  In the facilities described above, the raw water is simply drained after the intended treatment, or the drainage is not used as a resource, and the drainage is not effective from the viewpoint of resource utilization. In addition, there is room for improvement in the use of other systems for cycles, such as the use of cold heat from waste heat, by the proposed heat pump system for wastewater treatment facilities and the technology for effectively utilizing waste heat. .

  In addition, as described above, it is not preferable to produce hot water by heating newly received water with a boiler from the viewpoint of effective use of resources such as water and fuel, and energy such as electric power. .

  In view of such a situation, it is an object of the present invention to provide an effective wastewater utilization technique that can obtain desired hot water such as cleaning water from wastewater with more resource saving and energy saving.

The present invention employs the following means in order to solve the above-described problems. That is, the present invention provides an air conditioning system having a purification treatment device that purifies wastewater and generates treated water, and a heat source system that receives cooling water from a cooling tower and circulates and supplies cold water for air conditioning. A heat exchanger that circulates between the tower and the heat source unit and that has a higher temperature than the treated water is introduced, and heat-exchanges the treated water with the cooling water to raise the temperature, and the heat A heat recovery heat pump that absorbs the treated water that has been heated by the exchanger and flows in from the cold water that is returned to the heat source unit of the air conditioning system, further raises the temperature, and supplies the heated treated water to the hot water demand facility. It is a wastewater utilization system.

  According to the present invention, the waste water is purified and the temperature is raised by heat interchange with an air conditioning system that is another temperature utilization system (cold energy demand system). Therefore, it is possible to supply hot water purified by effectively using waste water. In addition, since the cooling of cooling water and cooling water of the air conditioning system, which is the cooling heat medium of the cold energy demand system, and the temperature of the treated water are performed together, energy such as electric power as a whole is compared with the case where each is performed independently. Consumption of resources such as fuel and fuel is further suppressed. Therefore, the waste water can be effectively used, and the air conditioning system can be operated and desired hot water can be supplied with less resources and more energy.

  In a water-cooled air conditioning system, the cooling capacity of the cooling tower is reduced in summer when the outside air temperature is higher than in winter, and cooling water that remains hot may be supplied to heat source equipment such as a refrigerator. . In such a case, energy consumption efficiency such as a cooling capacity per power consumption related to the heat source device is lowered. According to the present invention, heat is exchanged between such high-temperature cooling water and treated water, the cooling water supplied to the heat source unit is lowered, and the treated water is heated. Therefore, while improving the energy efficiency of a heat source machine, desired warm water can be obtained using the heat which cooling water contains. Therefore, the operation of the air conditioning system and the production and supply of hot water can be performed with more energy saving.

  Moreover, in the wastewater utilization system according to the present invention, the hot water demand facility may be a washing facility.

  According to the present invention as described above, cleaning water that is warm water heated to a desired temperature and has an appropriate water quality can be supplied with reduced resources and energy.

  Moreover, the waste water utilization system which concerns on this invention WHEREIN: The said purification treatment apparatus may purify the said waste water using a filtration membrane.

  Further, the present invention provides the cooling tower and the heat source in an air conditioning system having a heat source device that purifies wastewater to generate treated water, receives a supply of cooling water from the cooling tower, and circulates and supplies cold water for air conditioning. The temperature of the treated water is increased by exchanging heat with the cooling water having a temperature higher than that of the treated water. It may be a wastewater utilization method that absorbs heat from the cold water that is returned to the heat source unit of the system, further increases the temperature, and supplies the heated treated water to the hot water demand facility.

  ADVANTAGE OF THE INVENTION According to this invention, desired warm water, such as washing water, can be obtained from waste water with more resource saving and energy saving.

FIG. 1 is a configuration diagram illustrating a wastewater utilization system and the like according to the embodiment. FIG. 2 is a diagram illustrating a configuration example for lowering the temperature of the wastewater by heat exchange with the treated water. FIG. 3 is an explanatory diagram illustrating the operation of the wastewater utilization system in the summer. FIG. 4 is an explanatory diagram illustrating the operation of the wastewater utilization system in winter.

  Hereinafter, embodiments of the present invention (hereinafter also referred to as “present embodiments”) will be described with reference to the drawings. The embodiment described below shows an example for carrying out the present invention, and the present invention is not limited to a specific configuration described below. In practicing the present invention, it is preferable to adopt a specific configuration according to the embodiment as appropriate.

  The wastewater utilization system according to the present embodiment is described as a system that collects wastewater discharged from a production facility, generates purified hot water, and supplies the generated hot water to cleaning equipment that is a hot water demand facility. . Note that the wastewater utilization system may use wastewater collected from facilities other than the production facility. The air conditioning system according to the present embodiment is a cold energy demand system having a demand for cold energy, and is described as a water cooling type air conditioning system in which cooling water or cold water is circulated as a cooling heat medium. In the present embodiment, the drainage utilization system and the air conditioning system are described as separate systems, but the drainage utilization system may be implemented as a system including an air conditioning system.

<Configuration>
FIG. 1 is a configuration diagram illustrating a wastewater utilization system and the like according to this embodiment. FIG. 1 shows a wastewater utilization system 1, a production facility 2, an air conditioning system 3, and a cleaning facility 4. Between the wastewater utilization system 1 and the production facility 2, a water channel for supplying wastewater through a wastewater treatment tank 21 is provided. Between the wastewater utilization system 1 and the cleaning facility 4, a water channel for supplying hot water from the wastewater utilization system 1 to the cleaning facility 4 is provided. Between the air conditioning system 3 and the wastewater utilization system 1, a water channel is provided for drawing cooling water and cold water of the air conditioning system 3 from the air conditioning system 3 to the wastewater utilization system 1 and returning it to the air conditioning system 3. In FIG. 1, the direction of the arrow indicates the direction of the water flow in the water channel. In addition, it is preferable that each water channel employ | adopts structures, such as a material with high heat retention and a heat insulating material coating | cover. Hereinafter, the details of the configuration will be described in the order of the production facility 2, the air conditioning system 3, the wastewater utilization system 1, and the cleaning equipment 4.

  The production facility 2 is a facility such as a factory where production activities are performed. The production facility 2 discharges waste water along with production activities. The discharged waste water is temporarily stored in the waste water treatment tank 21. The wastewater stored in the wastewater treatment tank 21 is sent out by the pump P11 and supplied to the UF membrane treatment system 11 of the wastewater utilization system 1. That is, the waste water is purified and collected without being discarded.

  The air conditioning system 3 is a water-cooled air conditioning facility. The air conditioning system 3 includes a refrigerator 31, a cooling tower 32, and an air conditioner 32. The air conditioning system 3 is provided with a cooling water circulation channel in which the pump P34 is installed, and the cooling water flows through the refrigerator 31 and the cooling tower 32. The air conditioning system 3 is provided with a cold water circulation channel in which pumps P33 and P35 are installed, and the cold water flows through the refrigerator 31 and the air conditioner 33.

  The refrigerating machine 31 is a heat source unit that receives electric power or the like as power and circulates and supplies cooling water from the cooling tower 32 and circulates and supplies cold air for air conditioning to the air conditioner 33. The refrigerator 31 lowers the temperature of cold water flowing into an endothermic site such as an evaporator of the refrigerator 31 to a predetermined temperature and supplies the cold water to the air conditioner 33. The cooling water that has flowed into the refrigerator 31 is heated by a heat generating part such as a condenser or a regenerator of the refrigerator 31, and then travels to the cooling tower 32. When the temperature of the cooling water flowing into the refrigerator 31 is higher than a predetermined temperature, the energy efficiency in the refrigerator 31 is lowered.

  The cooling tower 32 is installed outdoors or the like, cools the inflowing cooling water by exchanging heat with the atmosphere or the like, and supplies it to the refrigerator 31. In summer when the temperature is high, the cooling capacity of the cooling tower 32 may decrease.

  The air conditioner 33 performs heat exchange between the supplied cold water and indoor air. An example of the air conditioner 33 is a fan coil unit. The heated cold water after the heat exchange is returned to the refrigerator 31.

  The drainage utilization system 1 is a system that supplies desired hot water using the drainage discharged from the production facility 2 and collected. The wastewater utilization system 1 includes a UF membrane treatment system 11, a treatment water tank 12, a heat recovery heat exchanger 13, and a heat recovery heat pump 14. The wastewater utilization system 1 is provided with a water channel for treated water in which a pump P12 is installed, and treated water supplied from the UF membrane treatment system 11 is treated water tank 12, heat recovery heat exchanger 13, heat recovery. It passes through the heat pump 14 in order and is supplied to the washing facility 4 as warm water.

  The UF membrane treatment system 11 is a purification treatment apparatus. The UF membrane treatment system 11 purifies the wastewater with waste heat supplied from the wastewater treatment tank 21 using a UF membrane (ultrafiltration membrane) to generate treated water of a predetermined water quality. Examples of the UF film include a spiral PVDF (polyvinylidene fluoride) film having a molecular weight cut-off of 150,000 and a diameter of 8 inches. The UF membrane treatment system 11 purifies wastewater and supplies treated water to the treated water tank 12. Instead of the UF membrane treatment system 11, a system that performs purification treatment using an RO membrane (reverse osmosis membrane) or other purification devices may be employed.

  In addition, you may further provide the heat exchanger which heat-exchanges between the waste_water | drain which goes to the UF membrane processing system 11 from the waste water treatment tank 21, and the treated water which goes to the treated water tank 12 from the UF membrane treatment system 11. For example, as shown in FIG. 2, a heat exchanger 15 is provided on the upstream side of the UF membrane treatment system 11, and a heat exchanger 16 is provided on the downstream side, and a heat medium such as water is transferred to the heat exchanger 15 and the heat exchanger by a pump P13. The heat exchange may be performed by circulating between 16. In this case, the heat of the waste water can be absorbed by the heat exchanger 15 and radiated to the treated water by the heat exchanger 16 via the circulating heat medium. By doing in this way, the temperature of the waste water which goes to the UF membrane processing system 11 can be temperature-fallen, and the temperature of the treated water which goes to the treated water tank 12 can be raised by the said heat exchange. Therefore, when the wastewater supplied from the treated water tank 12 to the UF membrane treatment system 11 exceeds the heat resistant temperature of the UF membrane, the temperature of the wastewater is discarded while the temperature of the wastewater is lowered to a temperature within the heat resistant temperature of the UF membrane. It is possible to use it effectively without using it.

  The treated water tank 12 temporarily stores treated water. The treated water tank 12 plays a role of stabilizing the amount of treated water supplied. In addition, for the treated water stored in the treated water tank 12, water quality analysis or water quality confirmation using a turbidimeter is performed. The treated water stored in the treated water tank 12 is supplied to the heat recovery heat exchanger 13 by the pump P12. In addition, it is preferable that the material and structure with high heat retention are employ | adopted for the treated water tank 12. FIG.

  The heat recovery heat exchanger 13 exchanges heat between the treated water supplied from the treated water tank 12 and the cooling water flowing from the cooling water circulation channel in the air conditioning system 3. An example of the heat recovery heat exchanger 13 is a counter flow sensible heat exchanger. The treated water flows into the heat recovery heat exchanger 13 from the water channel shown on the right side in FIG. The cooling water is sent out by the pump P31 and flows into the heat recovery heat exchanger 13 from the water channel shown on the left side. The treated water flows through the heat recovery heat exchanger 13 and then is supplied to the heat recovery heat pump 14. The cooling water flows through the heat recovery heat exchanger 13, is then returned to the cooling water circulation channel, and is supplied to the refrigerator 31.

  According to the heat recovery heat exchanger 13 of the present embodiment, when the inflowing cooling water is at a higher temperature than the inflowing treatment water, the heat exchange causes the cooling water to fall and the treatment water to rise in temperature. . Therefore, while satisfying the cold demand of the air conditioning system 3, the heat recovered from the cooling water can be used to raise the temperature of the treated water.

In this embodiment, the cooling water from the cooling tower 32 toward the refrigerator 31 flows into the heat recovery heat exchanger 13 and exchanges heat with the treated water. However, the cooling water from the refrigerator 31 toward the cooling tower 32 Can be configured to flow into the heat recovery heat exchanger 13 and exchange heat with the treated water. However, since the energy efficiency of the refrigerator 31 can be further improved by lowering the temperature of the cooling water flowing into the refrigerator 31, heat exchange is performed between the cooling water from the cooling tower 32 toward the refrigerator 31 and the treated water. It is desirable to adopt a configuration to do so.

  The drainage system 1 is operated with the pump P31 in operation when the cooling water cooled by the cooling tower 32 is at a higher temperature than the treated water flowing from the treated water tank 12 into the heat recovery heat exchanger 13. . Specifically, such an operation is performed when the cooling capacity of the cooling tower 32 of the air conditioning system 3 is reduced in summer and the like and the cooling water is not sufficiently cooled. In addition, when the cooling water cooled by the cooling tower 32 is not at a higher temperature than the treated water flowing into the heat recovery heat exchanger 13 from the treated water tank 12, the wastewater utilization system 1 is operated in a state where the operation of the pump P31 is stopped. Is done. Specifically, such operation is performed when the cooling capacity of the cooling tower 32 of the air conditioning system 3 is sufficient in winter or the like.

  The wastewater utilization system 1 includes a thermometer that measures the temperature of the treated water flowing into the heat recovery heat exchanger 13 and a thermometer that measures the temperature of the cooling water from the cooling tower 32 to the refrigerator 31. It may be provided. In this case, the wastewater utilization system 1 is provided with an automatic control mechanism that operates the pump P31 when the measured temperature of the cooling water is higher than the measured temperature of the treated water and stops the pump P31 at other times. Good.

  The heat recovery heat pump 14 is a heat pump that raises the temperature of the treated water supplied from the heat recovery heat exchanger 13 by absorbing heat from the cold water flowing from the cold water circulation channel of the air conditioning system 3 (simultaneously releasing heat to the treated water). is there. The treated water flows into the heat recovery heat pump 14 from the water channel shown on the right side in FIG. The cold water is sent out by the pump P32 and flows into the heat recovery heat pump 14 from the water channel shown on the left side. The cold water that flows in here is cold water that is returned from the air conditioner 33 to the refrigerator 31 in the circulation channel of the cold water, that is, cold water after consuming heat. The heat recovery heat pump 14 performs heat transfer from the cold water to the treated water so as to raise the temperature of the treated water to a predetermined temperature (for example, 35 ° C. or higher). The heat recovery heat pump 14 supplies the treated water whose temperature has been raised to the cleaning facility 4. Further, the cold water cooled by the heat recovery heat pump 14 is returned to the circulation channel of the cold water and supplied to the refrigerator 31.

  According to the heat recovery heat pump 14 of the present embodiment, it is possible to satisfy the demand for cold air of the air conditioning system 3 that lowers the temperature of the cold water, and to use the heat absorbed from the cold water to raise the temperature of the treated water. In particular, when the temperature of the treated water is raised in the heat recovery heat exchanger 13, the temperature of the treated water is not raised in the heat recovery heat exchanger 13 and is raised to a predetermined temperature by the heat recovery heat pump 14 alone. Compared to the case, hot water having a desired temperature can be obtained with less heat transfer power. Moreover, since the obtained warm water is purified to an appropriate water quality, it can be used as cleaning water with high detergency.

  The cleaning facility 4 is a cleaning facility that demands hot water as cleaning water. The cleaning equipment 4 uses the heated treated water supplied from the heat recovery heat pump 14 as cleaning water. An example of the cleaning facility 4 is a facility for cleaning a transport container for food or the like with warm water of about 35 ° C. Note that the temperature of the object to be cleaned and the temperature of the hot water are not limited to such examples. The cleaning equipment 4 may clean vegetables, industrial products, and other things, for example. Although the cleaning equipment 4 is installed outside the production facility 2 in FIG. 1, it may be installed inside the production facility 2. In this case, the hot water used for cleaning in the cleaning facility 4 may be recovered as drainage and supplied to the drainage utilization system 1 again for use.

The cleaning equipment 4 is not limited to using only hot water supplied from the heat recovery heat pump 14, but also supplies hot water from another system, and adjusts the temperature and supply amount of the hot water from the other system. By doing so, the temperature of the hot water supplied to the cleaning equipment 4 may be adjusted. Further, the temperature may be adjusted by further raising the temperature of the hot water supplied from the heat recovery heat pump 14. Even in this case, the treated water supplied to the cleaning facility 4 is preheated, and consumption of energy such as electric power of the apparatus for separately raising the temperature and resources such as fuel are suppressed. Further, instead of the washing facility 4, other hot water demanding equipment such as a clothes washing machine and a hot water pool may be employed.

<Summer operation>
FIG. 3 is an explanatory diagram illustrating the operation of the wastewater utilization system 1 in the summer. In this example, the wastewater utilization system 1 is operated with the pump P31 operating. Therefore, the cooling water of the air conditioning system 3 is drawn into the wastewater utilization system 1, and the heat recovery heat exchanger 13 performs heat exchange between the cooling water and the treated water. In FIG. 3, treated water at 20 ° C. flows from the treated water tank 12 into the heat recovery heat exchanger 13. On the other hand, 30 ° C. cooling water, which is higher in temperature than the treated water, flows into the heat recovery heat exchanger 13 from the cooling water circulation channel. As described above, the cooling water is not sufficiently cooled because the cooling capacity of the cooling tower 32 is reduced. By the heat exchange between the treated water and the cooling water in the heat exchanger 13 for heat recovery, the treated water is heated to 28 ° C. and the cooling water is lowered to 23 ° C.

  In FIG. 3, the treated water heated to 28 ° C. in the heat recovery heat exchanger 13 flows into the heat recovery heat pump 14. On the other hand, cold water flows into the heat recovery heat pump 14 from the cold water circulation channel. In the heat recovery heat pump 14, the temperature of the cold water is lowered, and the temperature of the treated water is further raised to a predetermined temperature of 35 ° C.

  In addition, the temperature of a treated water, cooling water, and cold water is not limited to the temperature illustrated in FIG.

<Operation in winter>
FIG. 4 is an explanatory diagram illustrating the operation of the wastewater utilization system 1 in winter. In this example, the wastewater utilization system 1 is operated in a state where the operation of the pump P31 is stopped. Therefore, the cooling water of the air conditioning system 3 is not drawn into the wastewater utilization system 1, and the heat exchange between the cooling water and the treated water is not performed in the heat recovery heat exchanger 13. On the other hand, the pump P32 is operating, and the cold water is drawn into the wastewater utilization system 1. Therefore, in the heat recovery heat pump 14, the temperature of the cold water is lowered and the temperature of the treated water is raised to a predetermined temperature of 35 ° C. It should be noted that during the intermediate period such as spring and autumn, the operation similar to that in the winter season may be performed with the operation of the pump P31 being stopped.

  According to this embodiment described above, the waste water is collected, purified, and heated. Therefore, it is possible to generate purified hot water by effectively using the waste water. At this time, the temperature lowering of the cold water of the air conditioning system 3 and the temperature rising of the treated water are performed together. Therefore, as compared with the case where the cooling water temperature of the air conditioning system 3 and the temperature of the treated water are increased independently, the consumption of energy such as electric power, resources such as fuel and water is further suppressed as a whole. Therefore, the waste water can be effectively used, and the air conditioning system 3 can be operated and desired hot water can be supplied with less resources and more energy.

  In summer, heat exchange is further performed between the high-temperature cooling water of the air conditioning system 3 and the treated water. Therefore, the temperature of the cooling water supplied to the refrigerator 31 is lowered and the temperature of the treated water is raised. Therefore, the energy efficiency of the refrigerator 31 can be improved, and desired hot water can be obtained using the heat contained in the cooling water. Therefore, the operation of the air conditioning system 3 and the supply of hot water can be performed with further energy saving.

1 Wastewater utilization system 11 UF membrane treatment system (Purification treatment equipment)
12 Treated water tank 13 Heat exchanger for heat recovery (heat exchanger)
14 Heat recovery heat pump (heat pump)
15, 16 Heat exchanger 2 Production facility 21 Wastewater treatment tank 3 Air conditioning system 31 Refrigerator 32 Cooling tower 33 Air conditioner 4 Washing equipment (hot water demand equipment)
P11, P12, P13, P31, P32, P33, P34, P35 Pump

Claims (5)

A purification device that purifies wastewater and generates treated water;
In an air conditioning system having a heat source system that receives cooling water from a cooling tower and circulates and supplies cooling water for air conditioning, cooling water that circulates between the cooling tower and the heat source apparatus and is hotter than the treated water A heat exchanger that flows in and heat-exchanges the treated water with the cooling water to raise the temperature;
Heat recovery heat pump that heats up the treated water that has been heated by the heat exchanger and that flows back to the heat source unit of the air conditioning system from the cold water, further raises the temperature, and supplies the heated treated water to the hot water demand facility When,
Bei to give a,
The cold water that has been absorbed by the heat recovery heat pump and lowered in temperature is supplied to a heat source unit of the air conditioning system.
Wastewater utilization system.   The wastewater utilization system includes inflow control means for controlling the inflow of cooling water to the heat exchanger according to the temperature of treated water and the temperature of cooling water.
  The wastewater utilization system according to claim 1. The hot water demand facility is a washing facility,
The wastewater utilization system according to claim 1 or 2 . The purification treatment device purifies the waste water using a filtration membrane.
The wastewater utilization system according to any one of claims 1 to 3 . Purify the wastewater to produce treated water,
In an air conditioning system having a heat source unit that receives cooling water supply from a cooling tower and circulates and supplies cooling water for air conditioning, the cooling water that circulates between the cooling tower and the heat source unit and is hotter than the treated water; The temperature of the treated water is increased by exchanging heat,
The treated water that has been heated and flowed in by the heat exchange is absorbed from the cold water that is returned to the heat source unit of the air conditioning system to further raise the temperature, and the heated treated water is supplied to the hot water demand facility ,
The cold water that has been absorbed and lowered is supplied to a heat source unit of the air conditioning system.
Wastewater usage method.

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