JP2000024646A - Waste water discharging section - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a waste water discharging section capable of separating and extracting purified water at high ratio from waste water containing sludge by membrane filtration and efficiently utilizing energy by ice heat storage. SOLUTION: The waste water discharging section is provided with a purifying treatment tank for purifying the waste water, a membrane filtration tank 1, 2 receiving the waste water sent from the purifying tank and provided with a filtration membrane 13 for separating the waste water into sludge and the purified water by the suction force of a pump and a heat combination supply device 20 for concentrating and separating the contained sludge by the difference of the freezing speed by giving cold to the waste water in the membrane filtration tank 12 and for defrosting the frozen waste water and the sludge is separated and discharged by the defrosting operation of the heat combination supply device 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wastewater purification system for treating kitchen wastewater, gray water and sewage discharged from condominiums and the like, and uses the water in the membrane separation tank as a heat storage medium to reduce power supply waste heat and industrial waste heat. The present invention relates to a system for storing ice heat using nighttime electric power and utilizing the energy, and particularly relates to membrane filtration separation of solid matter such as kitchen waste and heat storage.

[0002]

2. Description of the Related Art With the spread of home appliances, computers, air conditioners, etc., the demand for electric power has been increasing rapidly year by year, and the peak load especially in summer has been increasing. However, there are many problems such as environmental conservation and difficulty in locating a power plant. It is also difficult to increase the power. Under these circumstances, in recent years, as a method of storing excess heat during the night by using surplus inexpensive nighttime power and leveling the peak power in the daytime, the method using ice heat storage has been mainly used for newly built commercial buildings. It has been spreading.

[0003] In the conventional ice heat storage method, cold heat is supplied via an external heat source to a coolant or heat storage material such as tap water filled in an ice heat storage tank having an adiabatic closed structure, and cooled to a temperature below ice temperature to perform a freezing process. The basic principle is that the cold energy is stored in the form of ice, and the adiabatic stored ice is melted to recover and use the cold when necessary.

On the other hand, the amount of water used is increasing year by year, and limited water resources are not polluted and drained, but are reused or purified and discharged so as not to have an adverse effect on the environment. There is increasing recognition that conserving water resources is also an important initiative. In recent years, regarding the conservation of water resources, wastewater has been treated in factories, companies, or regions, and purified water has been reused as flush water for flush toilets and sprinkling water. Similar water reuse initiatives have also begun in residential areas such as and residential complexes.

[0005] In addition, kitchen waste such as garbage generated in restaurant kitchens and home kitchens is difficult to burn at high temperature because it accounts for 30% of combustible garbage and has a large amount of water. It is one of the hated things.

[0006] In the treatment of kitchen garbage, a system for purifying kitchen garbage with water and a system for purifying the kitchen garbage together with sewage have been proposed. Therefore, it has been attracting attention as a system that can save the trouble of garbage disposal.

[0007] As described above, the leveling of energy by ice storage and the treatment of wastewater containing kitchen waste are highly effective for environmental preservation and improvement of the living environment, and both systems use or treat liquid. Have in common. Focusing on this common point, a system in which the heat storage function and the water treatment function are docked has already been proposed.For example, a heat storage method for making ice and storing ice by directly using wastewater from a building or the like has been proposed.
It has been proposed in JP-A-6-18069 and JP-A-10-73290.

An ice heat storage method described in Japanese Patent Application Laid-Open No. 6-18069 discloses a method of supplying and circulating a refrigerant from a refrigerant supply device to a heat transfer tube immersed in treated sewage introduced into an ice heat storage tank. It is configured to partially make ice around and discharge remaining unfrozen residual water to the outside of the tank. FIG.

In FIG. 4, the sewage to be treated is a sewage receiving tank 10.
1 and is taken out by the sewage feed pump 102 and sent to the screen device 103 to remove coarse dust and the like. The refuse removed by the screen device 103 is discharged to a drain tank 104. Then, the sewage to be treated from which the refuse is removed is sent to an oil-water separator 105 to separate the oil component, the oil component is discharged to a drainage tank 104, and the sewage to be treated excluding the refuse and the oil component is supplied to a treatment sewage receiving tank. Stored in 106.

In the ice heat storage tank 108, a refrigerant is supplied from the refrigerant supply device to the heat transfer tube and circulated to make ice around the heat transfer tube, and the remaining non-freezing residual water remaining thereafter is discharged out of the tank by the residual water discharge pump 109. . At the stage of discharging the unfrozen residual water from inside the ice heat storage tank 108, a part of the treated sewage is passed from the treated sewage receiving tank 106 through the heat exchanger 110 for recovering residual water cooling heat, and the ice heat storage tank 10
The non-freezing residual water discharged from 8 is subjected to cold heat exchange, and the cold stored in the non-freezing residual water is collected in the treated sewage and stored in the cold treated sewage receiving tank 111 as the cold treated sewage.

[0011] The remaining treated sewage from the treated sewage receiving tank 106 is stored in the chilled sewage receiving tank 111 through the middle water chilled heat recovery heat exchanger 118 and sent to the ice heat storage tank 108 by the chilled sewage feed pump 112. Cold treatment sewage receiving tank 11
After the cold treated sewage from 1 drains the unfrozen residual water from the ice heat storage tank 108, the cold water is injected into the ice heat storage tank 108 from the cold water receiving tank 116 by the cold water circulation pump 121, and the cold water is loaded. Circulating water as a circulating water through a load circulating water line including a cold heat supply heat exchanger 114 and a pump 113,
A heat exchanger 1 for supplying cold energy to the cold stored by the ice around the heat transfer tubes.
14 to a load 115.

The cold water containing the thawed water in the ice heat storage tank 108 from which the cold heat has been completely recovered in the cold heat supply heat exchanger 114 is discharged as cold cold water into the cold cold water receiving tank 116 and stored. Cold and middle water feed pump 1 from the cold and middle water receiving tank 116
The cold water is taken out by 17 and passed through a heat exchanger 118 for recovering cold water from middle water to exchange heat with the treated sewage, and the cold stored in the cold water is recovered in the treated sewage. The cold water from which the cold energy has been recovered is stored in the middle water tank 119 as middle water, and is appropriately taken out by the middle water supply pump 120 and used as toilet water.

On the other hand, the apparatus disclosed in Japanese Patent Application Laid-Open No. Hei 10-73290 is one in which an ice producing unit and a heat storage water tank are separated from each other, and ice is not made in the ice heat storage tank. And accumulate ice in the heat storage water tank,
Wastewater other than ice is discharged from the ice machine. FIG. 5 shows the outline.

Various wastewaters from buildings and the like are stored in a drainage tank 201 and sent to an ice maker 202. Ice machine 2
Numeral 02 is for producing pure ice by nighttime electric power controlled by the monitoring control device 203. Pure ice produced by the ice making machine 202 is accumulated in an ice heat storage water tank 204. The ice maker 202 is provided with a function of separating sewage,
The sewage separated by the ice making machine 202 is supplied to a sewage treatment apparatus 205.
Will be introduced. The condensate used for the load side air conditioner 206 is also introduced into the condensate water storage tank 207, and the condensate is also periodically made into pure ice by the ice maker 202.

[0015]

However, in the above-mentioned conventional heat storage method and waste water treatment apparatus, only a part of the water in the waste water is frozen in the ice heat storage. Therefore, only a part of the water is reused, and the merit of the freezing treatment is not sufficiently utilized from the viewpoint of the wastewater purification treatment. Rather, since conventional wastewater treatment equipment only freezes part of the wastewater, freezing operation is not necessary from the viewpoint of heat capacity to treat kitchen waste etc. in wastewater. Was considered good.

Further, in the conventional heat storage method and waste water treatment apparatus, a waste water treatment tank is required separately from the heat storage tank, so that the structure becomes complicated and a large occupied area must be ensured.

Furthermore, in particular, when performing wastewater treatment of kitchen garbage and sewage, generation of a certain amount of settled solid components is inevitable, and as a final treatment, it is necessary to periodically draw out treated water containing solid components. . For this reason, concentration of treated water is indispensable in order to reduce the operating cost of wastewater treatment and promote effective use of water.

Accordingly, an object of the present invention is to provide a wastewater treatment apparatus capable of separating and extracting purified water at a high ratio from wastewater containing solid components by membrane filtration, and effectively utilizing energy by ice heat storage. .

[0019]

According to the present invention, there is provided a wastewater treatment apparatus, comprising: a purification tank for purifying wastewater; receiving wastewater sent from the purification tank; And a filtration membrane provided with a filtration membrane for separation into purified water, and the solid waste contained in the membrane filtration tank is concentrated and separated by a difference in freezing rate by giving cold heat to the wastewater in the membrane filtration tank, and the frozen wastewater is separated. A co-heating device for thawing, wherein the solid component is separated and discharged by the thawing operation of the co-heating device.

In the present invention, a configuration may be adopted in which a heat exchanger for membrane filtration is disposed inside the filtration membrane, and the freeze-thaw process is performed from inside the filtration membrane.

Further, an aeration device for stirring the inside of the membrane filtration tank may be provided. In this case, a stirring prevention member for suppressing re-stirring by the agitation by the aeration device can be provided.

[0022]

DETAILED DESCRIPTION OF THE INVENTION The invention according to claim 1 is a purification treatment tank for purifying waste water, receiving waste water sent from the purification treatment tank, and purifying the waste water with sludge by suction of a pump. A membrane filtration tank provided with a filtration membrane for separating water and water, and the wastewater in the membrane filtration tank is cooled and concentrated to separate sludge solid components contained by a difference in freezing rate, and the frozen wastewater is thawed. The wastewater treatment device is provided with a co-heating device that separates and discharges the sludge by the thawing operation of the co-heating device, so that the sludge suspended in the membrane filtration tank is easily subjected to membrane filtration. As a result, clogging of the filtration membrane is less likely to occur, and an acceptable concentration of sludge in the membrane filtration tank can be increased. Therefore, there is an effect that the frequency of maintenance such as a solid component extraction operation can be reduced.

According to a second aspect of the present invention, there is provided the wastewater treatment apparatus according to the first aspect, wherein a heat exchanger for membrane filtration is provided in the filtration membrane. Since clean ice grows from the inside of the membrane and freezes outward, sludge and the like adhering to the surface of the filtration membrane can be removed from the filtration membrane surface, eliminating clogging of the filtration membrane and recovering filtration performance. It has the effect of being able to.

According to a third aspect of the present invention, an aeration device for stirring the inside of the membrane filtration tank is provided, and the sludge settled in the membrane filtration tank is prevented from being stirred again by the agitation of the aeration device. The wastewater treatment device according to claim 1 or 2, wherein a stirring prevention member is provided, so that the sludge can be prevented from adhering to the surface of the filtration membrane by agitation of the aeration device, so that the filtration performance of the filtration membrane is reduced. The sludge that has been concentrated and settled by the freeze-thaw process is prevented from re-diffusing upward due to the stirring of the aeration device, and the allowable sludge concentration in the membrane filtration tank can be further increased. Has the effect of reducing the frequency of maintenance.

In the present invention, the concentration separation means that when the wastewater containing sludge or the like is frozen, the water is frozen from the clean water side due to the difference in the freezing speed between the water and the solid component such as the contained sludge. It means that solid components such as contained sludge are gradually concentrated and denatured and agglomerated, and when thawed thereafter, water is easily dehydrated and finally the solid components can be made into a paste.

Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings. FIG. 1 shows an overall configuration diagram of a wastewater treatment apparatus according to an embodiment of the present invention.

In FIG. 1, a wastewater purifying apparatus 1 is connected to a primary storage tank 2 for temporarily storing wastewater containing kitchen waste and sewage and miscellaneous wastewater and adjusting the amount of treatment at a later stage. . The primary storage tank 2 is connected to a sewage pipe 4 through which sewage and miscellaneous wastewater discharged from a washroom, a washing machine, and a bath are connected. The sewage pipe 4 is installed in a kitchen of a building or a home kitchen. 3 for crushing raw garbage
Are connected.

A wastewater supply pump 5 is disposed between the primary storage tank 2 and the anaerobic tank 6 disposed in the wastewater purifying apparatus 1 so that the wastewater from the primary storage tank 2 can be sent to the anaerobic tank 6. An aeration tank 8 is connected to the downstream of the tank 6 by a first communication pipe 7 for transferring wastewater. This aeration tank 8
Is provided with an air blower 9 for blowing air from outside and an aeration nozzle 10 for injecting minute air bubbles. In addition, a wastewater purification device 1 is provided downstream of the aeration tank 8.
Of the membrane filtration tank 12 as a processing tank constituting the second communication pipe 1
Connect via 1 The membrane filtration tank 12 is provided with a filtration membrane 13 for filtering the treated water, a water discharge pump 14 for discharging the purified water filtered by the filtration membrane 13, and a water discharge pipe for discharging the purified water to a reuse destination or the like. 15 is connected. Reference numeral 16 denotes sludge settled toward the bottom of the membrane filtration tank 12.

Further, a cogeneration system 2 for generating and utilizing heat energy for cooling and freezing and heating and thawing the membrane filtration tank 12 mainly.
0 is provided. The cogeneration system 20 is operated and operated by a power supply unit 40, and includes a membrane filtration tank heat exchanger 21 installed in the membrane filtration tank 12, an aeration tank heat exchanger 22 installed in the aeration treatment tank 8, and an air conditioning unit 23. Are connected respectively. That is, the heat exchanger 21 of the membrane filtration tank is
, The wastewater in the membrane filtration tank 12 is frozen and thawed, and the aeration tank heat exchanger 22 receives the supply of heat energy from the cogeneration device 20 to treat the treated water in the aeration tank 8. The air conditioning unit 23 receives the supply of cold and hot heat from the cogeneration system 20 to perform air conditioning in the building and the room.

The heat cogeneration device 20 may be any heat cycle device that can generate and use cold and hot heat. However, if waste heat in a power plant or an industrial area is used, the amount of the power supply unit 40 can be reduced. In such a case, a means such as a heat pump or an absorption refrigeration cycle that can utilize waste heat is desirable because it can reduce the amount of energy and can save energy.

In the above configuration, the discharged garbage is pulverized while being supplied with water by a disposer 3 installed in the kitchen of the building or the kitchen of the home, and is discharged to the primary storage tank 2 as crushed garbage. At the same time, sewage and miscellaneous wastewater from the washroom and the washing machine are also discharged to the primary storage tank 2 via the sewage pipe 4. After the wastewater or the like containing these solids is primarily stored in the primary storage tank 2, the wastewater is supplied to an anaerobic tank 6 as a first-stage treatment tank of the wastewater purification device 1 by operation control of a wastewater supply pump 5.

Here, the purifying means of the waste water purifying apparatus 1 may be any method capable of purifying waste water, such as biological treatment, electrolytic treatment, or chemical treatment. In the present embodiment, an example using the biological treatment method is used. This will be described with reference to FIG.

First, in the anaerobic tank 6, the waste water from the primary storage tank 2 is subjected to anaerobic treatment to purify mainly the removal of nitrogen components. The treated water subjected to the anaerobic treatment in the anaerobic tank 6 flows into the aeration treatment tank 8 through the first communication pipe 7, and the air source generated by the air blower 9 is supplied to the aeration nozzle 1 in the aeration treatment tank 8.
0 is introduced. As a result, air is blown into the treated water as microbubbles in the aeration treatment tank 8, and organic components mainly due to oxidative decomposition and biological solidification are removed.

A filler or a fluidized filter bed for promoting the growth of microorganisms and the like may be introduced into the aeration tank 8, and oxidation or biological treatment may be performed by mixing ozone or the like into the air to be aerated. May be activated.

The treated water subjected to aeration or aerobic treatment in the aeration treatment tank 8 contains sludge generated as a result of biosolidification, and is sufficiently stirred by the aeration treatment. In a diffuse state. Therefore, the treated water in the aeration treatment tank 8 containing the diffused sludge is discharged to the second
The sludge is settled by being supplied to the inflow into the membrane filtration tank 12 through the communication pipe 11.

When there is no mechanism for stirring the treated water in the membrane filtration tank 12 and the treated water is close to a stationary state, the sludge having a specific gravity slightly larger than the water is settled downward by the action of gravity. It becomes sludge 16 and accumulates.
In addition, when utilizing the effect of gravity positively, it may be called a sedimentation tank or a sedimentation tank. In the present embodiment, in addition to the action of gravity, the sludge 16 is positively separated using the filtration membrane 13.

That is, when the water discharge pump 14 is operated to discharge the treated water from the water discharge pipe 15, the inside of the filtration membrane 13 becomes a negative pressure, and tries to suck the treated water around the filtration membrane 13. At this time, sludge 16 remaining and remaining in the treated water
By selecting a filtration membrane 13 that allows the passage of only fine particles having a diameter smaller than the size of purified water, the purified water sucked into the inside through the filtration membrane 13 is below the sludge concentration suitable for the purpose of reuse in the subsequent stage. Is filtered.

Further, the membrane filtration tank 12 in the present invention includes:
The membrane filter tank heat exchanger 21 is disposed and the membrane filter tank heat exchanger 21
Is connected to a cogeneration unit 20 for performing a freezing process at a temperature lower than the ice temperature or a thawing process at a temperature higher than the ice temperature.

The process of freezing and thawing the treated water is performed in a batch system. That is, the cogeneration apparatus 20 is operated at night to send cold heat to the membrane filter tank heat exchanger 21 to start the freezing process and freeze the treated water as the content of the membrane filter tank 12. At this time, the drainage supply pump 5 and the water discharge pump 14
Should be stopped. Then, on the next day, the frozen treated water is thawed while recovering cold heat by the membrane filter tank heat exchanger 21 provided in the membrane filter tank 12. The recovered cold heat is sent to an air conditioning unit 23 installed in a building or a room to be used as a heat source for cooling or the like.

Here, in the membrane filtration tank 12, the freezing process may be controlled so as to start from above or in the vicinity of the membrane and gradually spread downward or farther from the membrane. That is, it is preferable to freeze gradually from the upper side to the lower side or from the vicinity of the membrane to a distant place. In addition, the membrane filter tank heat exchanger 21
May be disposed above the membrane filtration tank 12 or in the vicinity of the filtration membrane 13 or may be configured with two or more heat exchangers in a plurality of arrangements,
It suffices if it is possible to freeze gradually from the upper side to the lower side or from the vicinity of the membrane to a distant place. Further, even if the amount of cooling energy or the amount of expected cooling load on the next day is small and the entire treated water in the membrane filtration tank 12 cannot be frozen, the filtration membrane 13
A certain effect can be obtained if the treated water in the vicinity of where is disposed can be frozen.

As described above, according to the present invention, the sludge in the waste water can be denatured and coagulated, and the solid-liquid separation can be facilitated. Here, the modified aggregation of the sludge in the wastewater will be described.

In a state where sludge and the like are in a suspended state,
There is pore water with weak binding force around the sludge particles. When the wastewater containing sludge having such pore water is frozen, first, freezing is started from water having a high purity and a high freezing point, and frozen as the ice grows. Thereby, the pore water existing between the sludges is easily sucked out by the growing ice and disappears, and as a result, the sludges approach and aggregate. If the freezing temperature is further lowered and the freezing proceeds,
When the internal water of the sludge freezes, the internal water is also sucked out.
This further improves cohesion and dehydration.

As described above, as a result of the freeze-thaw treatment, the sludge in the suspended state is easily aggregated and dehydrated, and therefore, the solid-liquid separation can be easily performed. Conventionally, there is no technical idea about such solid-liquid separation by denatured aggregation, and concentration and separation can be easily and effectively obtained by freezing operation and denatured aggregation.

Next, the state of freezing will be described. In the freezing of the aqueous solution, the freezing start temperature of pure water is 0 ° C. However, in the case of an aqueous solution containing sludge, the freezing point of water is lowered, and the freezing temperature is reduced in correlation with the concentration of sludge.

Now, the membrane filtration tank heat exchanger 2 of the membrane filtration tank 12
When the temperature of 1 is lower than the freezing point, the aqueous solution in the vicinity of the membrane filter heat exchanger 21 tends to freeze. At this time, if the mixture is gently frozen without adding stirring or the like, the freezing starts from the portion of the aqueous solution having a low sludge concentration, that is, a high freezing temperature. As a result, during the freezing process, an ice layer close to fresh water with less sludge is formed in the membrane filter heat exchanger 2.
1 and a layer of ice containing more sludge is formed as the distance from the membrane filter tank heat exchanger 21 increases.

If the membrane filter tank heat exchanger 21 is positioned above the membrane filter tank 3, the freezing process starts from the top and gradually spreads downward while adding the sedimentation effect of the sludge due to gravity. Ice is formed, and ice with a large amount of sludge is gradually formed from the upper side to the lower side.

Further, the sludge is denatured and agglomerated by the freezing treatment, so that the sludge is formed into a larger mass or a group, so that the sludge is apt to settle and settle, and the degree of diffusion of the solid component in the treated water is reduced by that much.

When the treated water in the membrane filtration tank 12 is freeze-thawed as described above, the sludge diffused in the treated water is denatured and agglomerated into a larger mass, and part of the sludge precipitates and precipitates to form a filtration membrane. 13 makes it easy to filter.

After the freezing and thawing treatment, water with relatively little sludge is obtained in the vicinity of the filtration membrane 13, and the deposits on the membrane surface of the filtration membrane 13 deposited and adhered during the filtration treatment are also frozen. As a result, it is possible to obtain an effect that, after thawing, deposits on the membrane surface fall into the surrounding treated water to clean the membrane surface. At this time, it is also effective to carry out backwashing from the inside of the filtration membrane 13 to the membrane filtration tank 12 with the water discharge pump 14 or a separately installed washing pump to further enhance the effect.

In the case where the deposits on the surface of the filtration membrane 13 are sufficiently removed by the freeze-thawing treatment, the backwashing or the like may not be necessary. Further, when the concentration of the sludge in the membrane filtration tank 12 exceeds the allowable level, the sludge 16 is pulled out with a recovery vacuum car or the like.

In general, sludge can be concentrated in the membrane filtration treatment, and the concentration of sludge in the membrane filtration tank 12 is positively increased. Higher concentration can be achieved as compared with the conventional sludge concentration at the time of membrane filtration.

Further, the aeration tank heat exchanger 22 connected to the cogeneration unit 20 is used for heating and keeping the temperature of the treated water in the aeration tank 8 low and unsuitable for biological treatment. Sometimes.

As described above, the treated water in the membrane filtration tank 12 for membrane filtration of the sludge generated in the wastewater purification treatment can be used as a cold storage tank by using the treated water as a heat storage material. It can be concentrated and separated, and it can remove deposits on the membrane surface. Therefore, it is possible to improve the membrane filtration performance and to perform the wastewater purification treatment more efficiently, and the concentration of sludge is also improved. As a result, the wastewater treatment facility can be made very simple and compact, and the amount of sludge water that becomes waste in wastewater treatment can be reduced, the ratio of effective use of water increases, and waste heat is recovered as refrigeration heat. Effective use of waste heat is possible.

In the above embodiment, the membrane filtration tank 1
Although the sludge 16 concentrated and settled in Step 2 is drawn out and disposed of, the sludge 16 may be returned from the membrane filtration tank 12 to the first-stage anaerobic tank 6 and subjected to reprocessing such as removal of nitrogen components. . In this case, when the temperature is low after the thawing, it is preferable to heat the mixture during the return and adjust the temperature to a temperature desirable for anaerobic treatment, and then transport the mixture to the anaerobic tank 6.

FIG. 2 shows a configuration diagram of a membrane filtration tank according to another embodiment of the present invention. In this example, a heat exchanger 30 for a filtration membrane is arranged inside a filtration membrane 13, and the other configuration is the same as that shown in FIG. 1. Detailed description is omitted.

When freezing the inside of the treated water in the membrane filtration tank 12, the cold heat is fed from the cogeneration device 20 to the heat exchanger 30 for the filtration membrane, and the operation is performed so that the inside of the filtration membrane 13 is frozen. . Then, the purified water remaining in the filtration membrane 13 remaining after the filtration is frozen, and accumulated and expanded by the freezing, so that the deposits clogging the outer surface of the filtration membrane 13 and the inside of the filtration membrane 13 are removed from the inside to the outside. By pressing the film, the film is regenerated.

Further, the purified water having a small amount of sludge inside the filtration membrane 13 becomes a nucleus in the initial stage of freezing and the freezing range expands. Get higher.

In the thawing process, it is also possible to start thawing from the inside of the membrane. First, only the vicinity of the filtration membrane 13 is thawed, and the obtained water with little sludge is filtered and separated and extracted. Can also.

As described above, when the filtration membrane heat exchanger 30 is disposed inside the filtration membrane 13 and the freezing and thawing processes are performed from the inside of the filtration membrane 13, the surface for recovering the filtration performance of the filtration membrane 13 is recovered. And the effect of removing adhering matter in the film increases,
After the thawing, the molten water with little sludge obtained in the vicinity of the filtration membrane 13 can be extracted by filtration. Therefore, the sludge can be further concentrated, the wastewater treatment equipment can be made very simple and compact, and the work of extracting sludge water as waste in wastewater treatment can be reduced, and the ratio of effective use of water can be reduced. The waste heat can be recovered and used as refrigeration heat for effective use of waste heat.

FIG. 3 shows a configuration diagram of a membrane filtration tank according to still another embodiment of the present invention. In FIG. 3, the membrane filtration tank 1
2 is provided with a membrane aeration nozzle 10a for aeration in the vicinity of the filtration membrane 13 and agitation by air bubbles, and a sludge chamber 12 as an area for separating and storing the sludge 16 settled and settled.
a, and a re-diffusion prevention panel 12b as a stirring prevention member for preventing the stirring effect of the membrane aeration nozzle 10a from reaching the sludge 16 below the membrane filtration tank 12. Other configurations are the same as those shown in FIG.

When the treated water is filtered using the filtration membrane 13, as shown in the previous example, the treated water is subjected to membrane filtration while sedimentation and sedimentation is caused by the action of gravity. To prevent deposits from accumulating on the surface of the filtration membrane 13 during filtration. In the present embodiment, a freeze-thaw process is performed by the latter method.

In the state before the freezing treatment, the air source from the air blower 9 is supplied to the membrane aeration nozzle 10a so that the flow of the treated water due to the rise of bubbles near the filtration membrane 13 during the filtration treatment and the flow to the filtration membrane 13 The collision of air bubbles is created to prevent the accumulation of deposits on the surface of the filtration membrane 13. In this state, the water discharge pump 14 is operated to filter the treated water in the membrane filtration tank 12, extract purified water, and discharge water from the water discharge pipe 15. At this time, the sludge remaining in the treated water is stirred around the vicinity of the filtration membrane 13.

Then, at night, the generation of air bubbles from the membrane aeration nozzle 10a is stopped, the membrane filtration tank 12 is kept stationary, and the cogeneration system 20 is operated to operate the membrane filtration tank heat exchanger 21 and the heat exchange for the filtration membrane. Cold heat is sent to the vessel 30 to start the freezing process to freeze the treated water as the content of the membrane filtration tank 12.
The method of the freezing treatment and the like are the same as in the previous example, and the next day, the cold water is recovered by the heat exchanger 30 for the filtration membrane and the membrane heat exchanger 21 provided in the membrane filtration tank 12 while the frozen treated water is recovered. Is decompressed. The recovered cold heat is sent to an air conditioning unit 23 installed in a building or a room to be used as a heat source for cooling or the like.

When the treated water in the membrane filtration tank 12 is freeze-thawed as described above, the sludge 1
6 is denatured and agglomerated to form a larger mass. Also,
The sludge 16 is concentrated by the action of the freezing point lowering when the water is frozen, and settles down below the rediffusion prevention panel 12b.

A part of the membrane filtration tank 12 is a sludge chamber 12a which is isolated so as not to receive the stirring action by aeration.
The concentrated sludge that has settled and settled below the re-diffusion prevention panel 12b is stored in the sludge chamber 12a.

As described above, if the sludge 16 after the thawing treatment is isolated and stored by the re-diffusion prevention panel 12b and the sludge chamber 12a, the membrane aeration nozzle 10 during the filtration treatment by the filtration membrane 13 is provided.
Even if aeration treatment is performed from a, the concentrated sludge 16 can be prevented from diffusing again into the treated water, and both the effect of condensing and settling the sludge by freeze-thawing treatment and the effect of maintaining the filtration performance by membrane aeration can be obtained. Can be used successfully.

The sludge chamber 12a also serves to increase the concentration of the extracted sludge and minimize the amount of the extracted sludge by preferentially extracting the concentrated sludge 16 in the operation of extracting the sludge water. Sludge 16
If there is a means that can preferentially pull out the redistribution, only the re-diffusion prevention panel 12b may be provided.

[0068]

According to the first aspect of the present invention, the solid components suspended in the membrane filtration tank are easily filtered by the membrane, and clogging of the filtration membrane hardly occurs. Since the sludge concentration in the inside can be increased, the frequency of maintenance such as sludge water extraction work can be reduced.

According to the second aspect of the present invention, the sludge deposited on the surface of the filtration membrane is removed from the surface of the filtration membrane because clean ice grows from the inside of the filtration membrane and freezes to the outside by the freezing and thawing treatment. It is possible to eliminate clogging of the filtration membrane and recover filtration performance.

According to the third aspect of the present invention, it is possible to prevent the sludge from adhering and depositing on the surface of the filtration membrane by stirring the aeration device, so that the filtration performance of the filtration membrane can be maintained, and the sludge concentrated and settled by the freeze-thaw treatment is aerated. There is no re-diffusion upward due to stirring of the device. Therefore, the allowable sludge concentration in the membrane filtration tank can be further increased, and the frequency of maintenance such as sludge water extraction work can be reduced.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a wastewater treatment apparatus according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a membrane filtration tank according to another embodiment of the present invention.

FIG. 3 is a configuration diagram of a membrane filtration tank according to still another embodiment of the present invention.

FIG. 4 is a diagram showing a conventional technique described in Japanese Patent Application Laid-Open No. 6-18069.

FIG. 5 is a diagram showing a conventional technique described in JP-A-10-73290.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Drainage purification apparatus 2 Primary storage tank 3 Disposer 4 Sewage pipe 5 Drainage supply pump 6 Anaerobic tank 7 First communication pipe 8 Aeration treatment tank 9 Air blower 10 Aeration nozzle 10a Membrane aeration nozzle 11 Second communication pipe 12 Membrane filtration tank 12a Sludge Room 12b Re-diffusion prevention panel 13 Filtration membrane 14 Water discharge pump 15 Water discharge pipe 16 Sludge 20 Cogeneration system 21 Membrane filtration tank heat exchanger 22 Aeration tank heat exchanger 23 Air conditioning unit 30 Filtration membrane heat exchanger 40 Power supply unit

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F24F 5/00 102 B09B 5/00 ZABP F term (Reference) 4D006 GA07 KA01 KA02 KA12 KA15 KA44 KA47 KA72 KB13 KB23 KE16Q PB08 PC63 PC64 4D037 AA11 AB02 BA21 CA03 CA07 4D059 AA06 AA07 BA31 BA52 BE14 BE31 BF03 BF06 BF10 BJ20 CA09 EA06 EB06

Claims (3)

[Claims] 1. A purification tank for purifying waste water, and a filtration membrane for receiving the waste water sent from the purification tank and separating the waste water into sludge and purified water by suction of a pump. A membrane filtration tank, and a cogeneration unit that applies cold heat to the wastewater in the membrane filtration tank to concentrate and separate sludge solid components contained by a difference in freezing speed and defrosts the frozen wastewater. A wastewater treatment apparatus characterized in that sludge is separated and discharged by thawing operation of the apparatus. 2. A wastewater treatment apparatus according to claim 1, wherein a heat exchanger for membrane filtration is provided in said filtration membrane. 3. An aeration device for agitating the inside of the membrane filtration tank, and an agitation preventing member for preventing sludge settled in the membrane filtration tank from being agitated again by the agitation of the aeration device is provided. The wastewater treatment device according to claim 1 or 2, wherein: