JP2022036482A - Sewage treatment apparatus, sewage treatment unit, and sewage treatment method - Google Patents

Abstract

To provide a sewage treatment apparatus, a sewage treatment unit, and a sewage treatment method capable of reducing a cost of treating sewage and stably making the sewage into treated water that conforms to water quality standards.SOLUTION: A sewage treatment apparatus includes a first treatment tank in which sewage is treated by at least one of anaerobic treatment and solid-liquid separation, an intermediate treatment tank for anaerobic treatment, and a final treatment tank for anaerobic treatment or sedimentation separation. The sewage treatment apparatus further includes an airlift pipe with one end located at the bottom of the final treatment tank and the other end located above the first treatment tank, and an air supply pipe with one end which can be connected to an air supply unit located outside and the other end having a branched end. The end of the air supply pipe located in the final treatment tank is connected at one end of the airlift pipe so that air supplied from the air supply unit can be introduced into the airlift pipe.SELECTED DRAWING: Figure 3

Description

The present invention relates to a sewage treatment device, a sewage treatment unit, and a sewage treatment method.

As a device for treating sewage, an anaerobic treatment tank that passes sewage through a filter material to separate solids in the sewage and treats organic substances with anaerobic microorganisms, and aeration of the sewage supplied from this anaerobic treatment tank. A sewage treatment device equipped with an aeration treatment tank for treating with aerobic microorganisms is known.

The aeration in the aeration treatment is performed by supplying air to the aeration treatment tank by an air pump or the like installed together with the sewage treatment device. By reducing the amount of air supplied, it is required to reduce the electric power for operating the air pump and reduce the cost for sewage treatment.

A septic tank equipped with a backwash flow generator has been proposed (Japanese Patent Laid-Open No. 2010-207662). In this septic tank, air is stored in the upper part of the casing of the backwash flow generator, and the treated water in the casing flows in from one end of the extraction pipe by the air pressure and extends to the outside of the filtration tank at the other end. It is pushed out from the part. As a result, when the air pressure in the casing is released, the suction part of the extraction pipe sucks in a certain amount of the treatment liquid at once, and a rapid downward flow of the treatment liquid is generated in the filtration tank and adheres to the filter material. It is said that sludge can be effectively peeled off from the filter medium. Further, it is said that this peeling can be performed at regular intervals by continuously supplying air to the casing.

Japanese Unexamined Patent Publication No. 2010-207662

In the septic tank published in the above publication, at least the casing and the carrier flow tank for aerobic treatment are constantly supplied with air, so that the operating cost of the equipment for supplying air such as the air pump increases, and the sewage is sewage at low cost. It may not be possible to process.

In view of the above circumstances, the present invention can reduce the cost of treating sewage, and can stably make the sewage into treated water that meets the water quality standards, a sewage treatment device, a sewage treatment unit, and a sewage treatment. The purpose is to provide a method.

One aspect of the present invention made to solve the above problems is an anaerobic treatment of sewage in at least one of anaerobic treatment and solid-liquid separation, and sewage treated by the first treatment tank. It is provided with one or more intermediate treatment tanks for treatment and a final treatment tank for anaerobic treatment or sedimentation separation of the sewage treated by the intermediate treatment tank, one end of which is arranged at the bottom of the final treatment tank and the other end. Can be connected to an air lift pipe arranged in the upper part of the first treatment tank and an air supply machine having one end disposed externally, and the other end has a branched end portion, which is branched. The end portion has the first treatment tank, one or more intermediate treatment tanks, and the air supply pipes arranged in each of the final treatment tanks, and the air supply pipes arranged in the final treatment tank. Is a sewage treatment device connected at one end side of the air lift pipe so that the air supplied from the air supply machine can be introduced into the air lift pipe.

The sewage treatment device is arranged in a first treatment tank that treats the supplied sewage at at least one of anaerobic treatment and solid-liquid separation, and downstream thereof, and anaerobically treats the treated sewage. It is provided with a plurality of intermediate treatment tanks and a final treatment tank arranged downstream of the intermediate treatment tank and treating the anaerobic treated sewage by anaerobic treatment or precipitation separation. As described above, since the sewage treatment device treats the sewage a plurality of times, the sewage supplied to the sewage treatment device can be treated relatively easily to meet the water quality standard. Further, the sewage treatment device is connected to an air lift pipe that communicates the final treatment tank and the first treatment tank so that air supplied from an air supply machine arranged outside can be introduced into the air lift pipe. It is equipped with an air supply pipe. One end of the air lift pipe is arranged at the bottom of the final treatment tank, and the other end is arranged at the upper part of the first treatment tank. One end of the air supply pipe is connectable to the air supply machine, the other end is branched and has a plurality of ends, and the plurality of ends are the first treatment tank, one or a plurality of intermediate portions. It is placed in the treatment tank and the final treatment tank. The end of the plurality of ends arranged in the final treatment tank is connected at one end side of the air lift pipe so that the air can be introduced into the air lift pipe. By connecting one end of the air supply pipe to the air supply machine and supplying air into the air lift pipe, the air lift pipe can suck up the sewage from the final treatment tank and return it to the first treatment tank. can. By this reflux, nitrogen and the like in the first treatment tank can be reduced, and it is possible to suppress a decrease in the treatment efficiency of the sewage by the sewage treatment device. Therefore, the sewage treatment device can relatively stably turn the sewage into treated water that meets the water quality standard. The return of the sludge to the first treatment tank is carried out together with the inspection of the sewage treatment equipment specified by law, etc., or is carried out regularly or irregularly as necessary. The sewage treatment apparatus is composed of a first treatment tank for treating at least one of anaerobic treatment and solid-liquid separation, an intermediate treatment tank for anaerobic treatment, and a final treatment tank for anaerobic treatment or treatment by precipitation separation. Therefore, in the treatment of the sewage, it is not necessary to supply the air to any of the treatment tanks. That is, the sewage treatment apparatus does not need to supply the air for the treatment of the sewage, and needs to supply the air only when the sludge is returned to the first treatment tank. Therefore, the operation of the air supply machine can be stopped except when the sludge is recirculated, and the operation cost of the air supply machine can be reduced. That is, since the operating cost of the air supply machine is not incurred when the sewage treatment device normally treats the sewage, the sewage treatment device can reduce the cost of treating the sewage.

It is preferable that the sewage treatment apparatus does not have a treatment tank for aerobic treatment. That is, it is preferable that the sewage treatment apparatus does not aerate the sewage (aeration treatment). In order to treat aerobic sewage, it is necessary to supply air to the microorganisms for aerobic treatment, so that the cost of operating the air supply machine that supplies this air is incurred, and the cost of treating the sewage is high. May increase. By not performing the aerobic treatment, the cost of supplying air for the aerobic treatment is not incurred, so that the cost of treating the sewage can be further reduced.

The first treatment tank and one or more intermediate treatment tanks have a backwashing air diffuser for washing the carrier for anaerobic treatment, and are arranged in the first treatment tank and one or more intermediate treatment tanks. It is preferable that the end portion of the air supply pipe is connected so that the air supplied from the air supply machine can be introduced into the backwash air diffuser pipe. By doing so, for example, when the sludge is returned to the first treatment tank, the air is supplied to the backwashing air diffuser to allow the first treatment tank and one or more intermediate treatment tanks to work. The carrier for anaerobic treatment having the above can be washed. Therefore, the above-mentioned sewage can be made into treated water more stably and conforming to the water quality standard.

The final treatment tank has a backwashing air diffuser that is anaerobic and cleans the carrier for the anaerobic treatment, and the end of the air supply pipe arranged in the final treatment tank is branched. It is preferable that the air is connected to the inside of the air lift pipe and the inside of the backwashing air diffuser of the final treatment tank so that the air can be introduced. By doing so, the anaerobic carrier in the final treatment tank to be anaerobically treated can be washed, and the sewage can be more easily converted into treated water conforming to the water quality standard.

Another aspect of the present invention made to solve the above problems is sewage including the sewage treatment device and an air supply machine connected to the air supply pipe at the start of operation and inspection of the sewage treatment device. It is a processing unit.

The sewage treatment device included in the sewage treatment unit does not need to supply air to any of the treatment tanks in the normal sewage treatment. On the other hand, the air supply machine is connected to the air supply pipe at the time of inspection of the sewage treatment device to supply the air into the air lift pipe, and the sewage in the final treatment tank of the sewage treatment device is discharged to the first treatment tank. Reflux to. Further, the air supply machine is connected to the air supply pipe at the start of operation of the sewage treatment device to supply the air, and promotes the activity of the microorganisms that perform the anaerobic treatment. By doing so, the sewage treatment unit can shorten the period until the sewage treatment apparatus shifts to the normal operation for treating the sewage without receiving the supply of the air. As described above, the sewage treatment unit operates the air supply machine only at the start of operation and at the time of inspection, and does not operate the air supply machine in the normal treatment of the sewage, so that the cost for treating the sewage is reduced. can. Further, the sewage treatment unit can suppress the decrease in the treatment efficiency of the sewage by returning the sewage from the final treatment tank of the sewage treatment apparatus to the first treatment tank at the time of the inspection, thereby stabilizing the sewage. It can be treated water that meets the water quality standards.

Another aspect of the present invention made to solve the above problems is a method for treating sewage by the sewage treatment unit, in which the step of arranging the sewage treatment device and the air supply to the air supply pipe are provided. The machine is connected to supply air to at least the first treatment tank and one or more intermediate treatment tanks, and the sewage is supplied to the first treatment tank, one or more intermediate treatment tanks, and the final treatment tank in this order. The step of passing through and starting the treatment of the sewage, the step of disconnecting the connection between the air supply pipe and the air supply machine, stopping the supply of the air and treating the sewage, and the treatment of the sewage. To inspect the sewage treatment equipment by connecting the air supply machine to the air supply pipe and supplying air to at least one of the first treatment tank, the intermediate treatment tank and the final treatment tank. After the inspection, the connection between the air supply pipe and the air supply machine is disconnected, the supply of the air is stopped, and the treatment of the sewage is restarted.

In the sewage treatment method, in the step of starting the sewage treatment and the step of inspecting the sewage treatment device, the air supply machine is connected to the sewage treatment device to supply air. On the other hand, in the step in which the sewage treatment apparatus normally treats the sewage, the air supply machine is disconnected and does not supply the air. Therefore, the air supply machine can stop the operation of the air supply machine and reduce the cost required for the operation, at least in the step of treating the sewage normally. Therefore, the sewage treatment method can reduce the cost of treating the sewage. Further, in the inspection step, the air supply machine is connected to the air supply pipe and supplies the air to the air lift pipe to return the sewage from the final treatment tank of the sewage treatment device to the first treatment tank. Since it is possible to suppress a decrease in the treatment efficiency of the first treatment tank, the sewage can be easily converted into treated water that meets the water quality standard.

As described above, the sewage treatment device, the sewage treatment unit, and the sewage treatment method of the present invention can reduce the cost for treating sewage and can stably make the sewage into treated water conforming to the water quality standard.

FIG. 1 is a schematic plan view of a sewage treatment apparatus according to an aspect of the present invention. FIG. 2 is a right side view of the sewage treatment apparatus of FIG. FIG. 3 is a cross-sectional view taken along the line AA in the sewage treatment apparatus of FIG.

Hereinafter, the present invention will be described in detail with reference to the drawings. 1 to 3 are schematic views of a sewage treatment apparatus according to an aspect of the present invention.

[Sewage treatment equipment]
In the sewage treatment apparatus 1 according to one aspect of the present invention, the sewage is treated with anaerobic treatment and the sewage treated by the first treatment tank 2 is anaerobically treated. It is provided with one or a plurality of intermediate treatment tanks and a final treatment tank 5 for anaerobic treatment or precipitation separation of the sewage treated by the intermediate treatment tank. In this embodiment, it is assumed that two intermediate treatment tanks 3 and 4 are provided. The first treatment tank 2, the intermediate treatment tanks 3, 4 and the final treatment tank 5 are divided by partition walls 11, 12, and 13 in the sewage treatment device 1, and are arranged so that the sewage passes in this order. The sewage treatment device 1 has three inspection ports 14, 15 and 16 that can be opened and closed at the upper part. The sewage treatment device 1 has an inflow port 17 into which the sewage W flows into the upper part of the first treatment tank 2, and the treated sewage W is discharged to the upper part on the final treatment tank 5 side as treated water conforming to the water quality standard. It has an outlet 18.

[First treatment tank]
The first treatment tank 2 treats the sewage W flowing in from the inflow port 17 at least one of anaerobic treatment and solid-liquid separation. In the present embodiment, the first treatment tank 2 is anaerobic-treated and has a carrier for anaerobic treatment (not shown). The first treatment tank 2 has a lower surface screen 21 for preventing the anaerobic treatment carrier floating in the stored sewage W from flowing out, and a bottom screen 21 for preventing the anaerobic treatment carrier from floating on the water surface of the sewage. It has a top screen 22 to be used. A plurality of the anaerobic treatment carriers are arranged between the lower surface screen 21 and the upper surface screen 22 to form a filtration layer. The sewage W flowing in from the inflow port 17 is anaerobically treated by coming into contact with the plurality of the anaerobic treatment carriers forming the filtration layer (primary treatment). The first treatment tank 2 has a flow path 23 for supplying the primary treated sewage W to the intermediate treatment tank 3. Specifically, the flow path 23 is formed so as to communicate the bottom of the first treatment tank 2 with the discharge port 11a formed on the upper side of the partition wall 11. The sewage W at the bottom of the first treatment tank 2 rises in the flow path 23 due to water pressure, and is discharged from the discharge port 11a to the intermediate treatment tank 3.

The anaerobic treatment carrier carries an anaerobic microorganism that purifies the sewage W. The shape of the anaerobic treatment carrier is not particularly limited, and may be spherical, columnar, or the like, but is preferably tubular. The cylindrical cross-sectional shape is not particularly limited and may be rectangular, polygonal, elliptical or the like, but is preferably circular. By making the shape of the anaerobic treatment carrier cylindrical, the sewage W can pass through the gap formed inside the anaerobic treatment carrier and between the adjacent anaerobic treatment carriers, so that the sewage W can pass through. However, the resistance to pass through the filtration layer can be made relatively small.

[Intermediate treatment tank]
The intermediate treatment tank 3 anaerobically treats the sewage W that has undergone the primary treatment. The intermediate treatment tank 3 has an anaerobic treatment carrier for anaerobic treatment (not shown). The carrier for anaerobic treatment may be the same as that used in the first treatment tank 2, or may be different. Similar to the first treatment tank 2, the intermediate treatment tank 3 has a lower surface screen 31 and an upper surface screen 32, and a plurality of the anaerobic treatment carriers form a filtration layer between them. Further, the intermediate treatment tank 3 has a flow path 33 formed so as to communicate the bottom portion and the discharge port 12a formed on the upper side of the partition wall 12. The intermediate treatment tank 3 discharges the sewage W anaerobically treated (secondary treatment) with the anaerobic treatment carrier to the intermediate treatment tank 4.

The intermediate treatment tank 4 performs anaerobic treatment on the sewage W that has been subjected to the secondary treatment. Similar to the intermediate treatment tank 3, the intermediate treatment tank 4 has a carrier for anaerobic treatment (not shown), a bottom screen 41 and a top screen 42. The intermediate treatment tank 4 performs anaerobic treatment (tertiary treatment) on the secondary treated sewage W with a carrier for anaerobic treatment, and discharges the sewage W to the final treatment tank 5.

[Final processing tank]
In the final treatment tank 5, the tertiary treated sewage W is finally treated by an anaerobic treatment carrier or precipitation separation to obtain treated water conforming to the water quality standard. This treated water is discharged to the outside of the sewage treatment device 1 from the outlet 18. When the final treatment tank 5 anaerobically treats the sewage W with the anaerobic treatment carrier, the final treatment tank 5 has the anaerobic treatment carrier and the bottom screen and the top screen in the same manner as the intermediate treatment tanks 3 and 4. Have. In the present embodiment, the final treatment tank 5 treats the sewage W by precipitation separation.

The final treatment tank 5 precipitates suspended solids in the sewage W tertiaryly treated in the intermediate treatment tank 4, disinfects the supernatant of the sewage W with chlorine or the like, and uses the sewage W as treated water as the treated water from the sewage treatment apparatus. Discharge to the outside of 1. That is, the final treatment tank 5 has a settling section (not shown) for precipitating suspended solids in the sewage W and a disinfecting section (not shown) for disinfecting the supernatant of the sewage W.

The sewage W subjected to the tertiary treatment in the intermediate treatment tank 4 is discharged to the final treatment tank 5 from the discharge port 13a formed at the bottom of the partition wall 13. Therefore, the intermediate treatment tank 4 does not have a flow path for raising the sewage W at the bottom.

It is preferable that the sewage treatment device 1 does not aerobically treat the sewage W. That is, it is preferable that the first treatment tank 2, the intermediate treatment tanks 3 and 4, and the final treatment tank 5 do not have microorganisms that aerobically treat the sewage W. By doing so, it is not necessary to supply the air necessary for the aerobic treatment to the sewage W in the treatment of the sewage W, and the cost of treating the sewage W can be reduced.

The sewage treatment device 1 includes an air lift pipe 6 having one end arranged at the bottom of the final treatment tank 5 and the other end arranged at the upper part of the first treatment tank 2, and an air supply machine having one end arranged outside. Air that is connectable and has a branched end at the other end, and the branched end is arranged in each of the first treatment tank 2, the intermediate treatment tanks 3 and 4, and the final treatment tank 5. It has a supply pipe 7. The air supply pipe 7 introduces air supplied from the outside into the air lift pipe 6. The air lift pipe 6 returns the sewage W at the bottom of the final treatment tank 5 to the first treatment tank 2. At the same time as this reflux, the sludge accumulated at the bottom of the final treatment tank 5 (hereinafter, also referred to as “deposited sludge”) is transferred to the first treatment tank. The above-mentioned reflux may be performed together with the inspection of the sewage treatment device 1 specified by law, etc., or may be performed regularly or irregularly as necessary.

[Air lift pipe]
The air lift pipe 6 is arranged so that one end opens at the bottom of the final treatment tank 5 and the other end opens at the upper part of the first treatment tank 2. The other end of the air lift pipe 6 may be arranged at a place where the accumulated sludge is likely to accumulate, and the other end of the air lift pipe 6 may be arranged above the water surface of the sewage W stored in the first treatment tank 2. preferable. By doing so, the above-mentioned reflux and transfer can be made efficient.

By refluxing the sewage W of the final treatment tank 5 that has been subjected to the tertiary treatment to the first treatment tank 2, nitrogen and the like in the sewage W of the first treatment tank 2 are reduced, and the sewage W is treated by the sewage treatment device 1. It is possible to suppress the decrease in efficiency. Further, by transferring the accumulated sludge of the final treatment tank 5 at the same time, it is possible to suppress the decrease in the treatment efficiency of the final treatment tank 5 and further suppress the decrease in the treatment efficiency of the sewage W by the sewage treatment apparatus 1.

[Air supply pipe]
The air supply pipe 7 is opened at the upper part in the sewage treatment device 1 so that one end thereof is connected to an air supply machine (not shown) arranged outside. The other end of the air supply pipe 7 has a plurality of branched ends, and of these plurality of ends, the end arranged in the final treatment tank 5 is the sewage W stored in the final treatment tank 5. Below the surface of the water, the air supplied from the air supply machine is connected so as to be introduced into the air lift pipe 6. In FIGS. 1 to 3, the one end of the air supply pipe 7 is arranged so as to open upward on the lower side of the inspection port 16.

When the air supply pipe 7 introduces air into the air lift pipe 6, a part of the sewage W in the air lift pipe 6 rises and is discharged to the first treatment tank 2. At the same time, the pressure (atmospheric pressure) in the air lift pipe 6 becomes a negative pressure with respect to the pressure (water pressure) at the bottom of the final treatment tank 5, so that the sewage W in the final treatment tank 5 is sucked into the air lift pipe 6. It is discharged to the first treatment tank 2 and the above-mentioned reflux is performed. Along with the suction of the sewage W, the accumulated sludge in the final treatment tank 5 is sucked into the air lift pipe 6 and discharged to the first treatment tank 2.

The other end of the air supply pipe 7 is preferably connected to the air lift pipe 6 near the bottom of the final treatment tank 5. Specifically, it is preferable to connect the end portion of the air supply pipe 7 to the side wall near the one end portion of the air lift pipe 6 arranged at the bottom of the final treatment tank 5. By doing so, it is possible to easily increase the difference in pressure, and it is possible to efficiently suck the sewage W and the accumulated sludge. In addition, "near the bottom of the final treatment tank 5" is the ratio of the distance from the inner surface to the distance (height) from the inner surface of the bottom of the final treatment tank 5 to the water surface in the normal direction of the water surface of the sewage W. Means that is within 30%. The "distance from the inner surface of the bottom of the final treatment tank 5 to the water surface" means the maximum value when the bottom of the final treatment tank 5 is not formed parallel to the water surface.

[Backwash diffuser]
The sewage treatment apparatus 1 has a backwashing air diffuser in which the first treatment tank 2 and the intermediate treatment tanks 3 and 4 wash the carrier for the anaerobic treatment, and the first treatment tank 2 and the intermediate treatment tanks 3 and 4 have. It is preferable that the end portion of the air supply pipe 7 arranged in the air supply pipe 7 is connected so that the air supplied from the air supply machine can be introduced into the backwash air diffuser pipe.

The backwashing air diffuser has a plurality of air discharge ports, and by discharging air, the carrier for anaerobic treatment is washed. Specifically, the air discharged from the backwashing air diffuser comes into contact with the carrier and removes sludge adhering to the carrier (hereinafter referred to as "adhered sludge"). In addition, the discharge of the air causes the plurality of carriers forming the filtration layer to be agitated between the upper surface screen and the lower surface screen. The adhered sludge is removed by collisions between the carriers due to this stirring. In this way, the backwashing air diffuser cleans the carrier by removing the adhering sludge. In the anaerobic treatment using the carrier, excess sludge is generated due to anaerobic decomposition, and the excess sludge may block the inside of the carrier as the adhered sludge. The above-mentioned cleaning may be performed together with the inspection of the sewage treatment device 1 specified by law or the like, or may be performed regularly or irregularly as necessary. The sewage treatment device 1 provided with the backwashing air diffuser can suppress the decrease in the efficiency of anaerobic treatment by washing the carrier, so that the sewage W can be treated more stably and conform to the water quality standard. ..

The branched ends of the air supply pipes 7 arranged in the first treatment tank 2 and the intermediate treatment tanks 3 and 4, respectively, are connected to the backwash air diffuser pipes 81, 82 and 83, respectively. By doing so, air can be supplied to each of the backwashing air diffusers 81, 82, and 83. It is preferable that the air supply pipe 7 connected to each of the backwash air diffuser pipes 81, 82, and 83 has a valve that can switch between the supply of the air and its stop. By doing so, the air can be supplied only to the treatment tank that requires cleaning of the carrier. Further, the air supply pipe 7 has a valve on the upstream side of the branch that can switch between the supply of the air to the backwash diffuser pipes 81, 82 and 83 and the supply of the air to the air lift pipe 6. It is preferable to have. By doing so, the reflux of the sewage and the washing of the carrier can be performed individually.

The backwash diffuser pipes 81, 82, 83 are arranged near the bottoms of the first treatment tank 2 and the intermediate treatment tanks 3, 4. Specifically, it is arranged under the filtration layer formed of the carrier, and the plurality of air outlets are formed so as to open toward the carrier. In FIG. 3, the backwash diffuser tubes 81, 82, 83 are arranged on the upper surface side of the lower screens 21, 31, 41. By doing so, the discharged air can easily come into contact with the carrier and the carrier can be easily agitated. In addition, "near the bottom of the intermediate treatment tanks 3 and 4" means the distance (height) from the inner surface of the bottom of the intermediate treatment tanks 3 and 4 to the water surface in the normal direction of the water surface of the sewage W from the inner surface. It means that the ratio of the distances is within 40%.

The final treatment tank 5 has a backwashing air diffuser that performs anaerobic treatment and cleans the carrier for the anaerobic treatment, and the end portion of the air supply pipe 7 in the final treatment tank 5 is branched into the air lift pipe 6. It is preferable that the air is connected to the inside of the backwashing air diffuser of the final treatment tank 5 so that the air can be introduced. That is, when the final treatment in the final treatment tank 5 is an anaerobic treatment, it is preferable that the backwashing air diffuser for washing the carrier for the anaerobic treatment is arranged in the final treatment tank 5. By doing so, even when all the treatment tanks are subjected to anaerobic treatment, the sewage W can be stably treated as treated water conforming to the water quality standard. In the air supply pipe 7, the end of the air supply pipe 7 connected to the air lift pipe 6 is branched, one end of the branched air supply pipe 7 is connected to the air lift pipe 6, and the other end is connected. Is connected to the backwashing air diffuser of the final treatment tank 5. By doing so, the above air can be supplied to the backwashing air diffuser of the final treatment tank 5. The air supply pipe 7 preferably has a valve capable of switching between the supply of the air to the air lift pipe 6 and the supply of the air to the backwashing air diffuser pipe. By doing so, the reflux of the sewage W and the washing of the carrier can be performed individually.

[advantage]
The sewage treatment device 1 does not need to supply air to the first treatment tank 2, the intermediate treatment tanks 3, 4 and the final treatment tank 5 in the normal treatment of the sewage W, and the cost for operating the air supply machine is high. Is not generated, so that the cost of treating the sewage W can be reduced. Further, since the sewage treatment device 1 includes an air lift pipe 6 that recirculates the sewage W of the final treatment tank 5 to the first treatment tank 1, it is possible to suppress a decrease in the treatment efficiency of the sewage W. Therefore, the sewage treatment device 1 can stably make the sewage W into treated water that meets the water quality standard. Since the sewage treatment device 1 includes an air supply pipe 7 that introduces the supplied air into the air lift pipe 6, the sewage W can be returned to the first treatment tank 2 relatively easily.

[Sewage treatment unit]
The sewage treatment unit according to another embodiment of the present invention includes the above-mentioned sewage treatment device 1 and an air supply machine connected to the air supply pipe 7 at the start of operation and at the time of inspection of the sewage treatment device 1.

The air supply machine is connected to the sewage treatment device 1 at the start of operation and at the time of inspection of the sewage treatment device 1, and the connection is disconnected except at the start of operation and at the time of inspection to supply air to the sewage treatment device 1. There is no. Therefore, the cost for operating the air supply machine can be reduced.

[advantage]
Since the sewage treatment unit does not require the supply of air in the normal treatment of the sewage W, the operating cost of the air supply machine can be reduced, and the cost of treating the sewage W can be reduced.

[Sewage treatment method]
The sewage treatment method according to another embodiment of the present invention is a method for treating sewage W by the sewage treatment unit, in which the step of arranging the sewage treatment device 1 and the air supply device in the air supply pipe 7 are provided. While connecting and supplying air to at least the first treatment tank 1 and one or more intermediate treatment tanks, the sewage W passes through the first treatment tank 1, one or more intermediate treatment tanks, and the final treatment tank 5 in this order. The step of starting the treatment of the sewage W, the step of disconnecting the connection between the air supply pipe 7 and the air supply machine, stopping the supply of the air, and treating the sewage W, and the treatment of the sewage W. Is interrupted, the above air supply machine is connected to the air supply pipe 7, and air is supplied to at least one of the first treatment tank 5, one or more intermediate treatment tanks and the final treatment tank 5, and the sewage treatment device 1 is used. It mainly includes a step of inspecting and a step of disconnecting the connection between the air supply pipe 7 and the air supply machine after the inspection, stopping the supply of the air, and restarting the treatment of the sewage W.

[Arrangement process]
In the disposing step, the sewage treatment device 1 is disposed. The air supply machine may or may not be arranged together with the sewage treatment device 1. The sewage treatment device 1 is mainly arranged in the ground, and the sewage supply pipe for supplying the sewage W to the sewage treatment device 1 is connected to the inflow port 17, and the sewage W finally treated by the sewage treatment device 1 is discharged. The sewage discharge pipe to be treated and the outlet 18 are connected.

[Processing start process]
In the treatment start step, the air supply machine is connected to the air supply pipe 7, and the sewage W is supplied while supplying air to at least one of the first treatment tank 2, the intermediate treatment tanks 3, 4 and the final treatment tank 5. The first treatment tank 2, the intermediate treatment tanks 3 and 4, and the final treatment tank 5 are passed in this order to start the treatment. That is, the treatment start step is a step of starting the operation of the arranged sewage treatment device 1. In this step, the air is supplied from the air supply machine to the anaerobic treatment tank among the plurality of treatment tanks, and the activity of the microorganisms carried by the carrier for the anaerobic treatment is promoted. Specifically, one end of the air supply pipe 7 of the sewage treatment device 1 is connected to the air supply machine, and the first treatment tank 2 and the intermediate treatment tanks 3 and 4 are connected from the branched end of the air supply pipe 7. Supply air to. When the sewage treatment device 1 has backwashing air diffusers 81, 82, 83, the air may be discharged from the backwashing air diffusers 81, 82, 83.

It is not always necessary to supply the above air in the treatment start step, but if the above air is not supplied, the activity of the above microorganisms becomes sufficient and the sewage W can be treated as treated water conforming to the water quality standard. It takes a long time to do so. By supplying the air and promoting the activity of the microorganisms, the sewage treatment device 1 shifts to a normal operation in which the sewage W can be stably treated as treated water conforming to the water quality standard without receiving the supply of the air. It is possible to shorten the period until it is done.

[Processing process]
In the purification step, the connection between the air supply pipe 7 and the air supply machine is disconnected, the supply of the air is stopped, and the sewage W is treated. The treatment step is a state in which the sewage treatment device 1 is in normal operation. The first treatment tank 2 and the intermediate treatment tanks 3 and 4 anaerobically treat the sewage W with microorganisms that have been made to be able to perform sufficient activities in the purification start step. Since the sewage treatment apparatus 1 does not have a treatment tank for aerobic treatment with aerobic microorganisms, the above air supply is not required in the treatment step (normal operation). Therefore, in the normal operation of the sewage treatment device 1, the cost of operating the air supply device is not incurred. In addition, "disconnecting" means not only the state in which the one end of the air supply pipe 7 and the air supply machine are separated, but also the state in which the one end of the air supply pipe 7 and the air supply machine are connected. It also includes a state in which the supply of air by the air supply machine is stopped.

[Inspection process]
In the inspection process, the treatment of the sewage W is stopped, the above air supply machine is connected to the air supply pipe 7, and air is supplied to at least one of the first treatment tank 2, the intermediate treatment tanks 3, 4 and the final treatment tank 5. Then, inspect the sewage treatment device 1. The inspection process may be performed together with the inspection of the sewage treatment device 1 specified by law or the like, or may be performed regularly or irregularly as necessary. If possible, the sewage W treatment may be performed while continuing the sewage treatment without stopping.

In the inspection step, the sewage W of the final treatment tank 5 is returned to the first treatment tank 2 by the air lift pipe 6. Specifically, the air supplied from the air supply machine is introduced into the air lift pipe 7 via the air supply pipe 7, and the sewage W of the final treatment tank 5 is sucked by the air lift pipe 7 to be the first treatment tank. Discharge to 2.

It is preferable that the sewage treatment apparatus 1 includes backwashing air diffusers 81, 82, 83, and the inspection step includes a step of cleaning the anaerobic treatment carrier with the backwashing air diffusers 81, 82, 83.

[Washing process]
In the washing step, the anaerobic treatment carrier is washed with the backwashing diffuser tubes 81, 82, 83. Specifically, the air supplied from the air supply machine is introduced into the backwashing air diffuser pipes 81, 82, 83 via the air supply pipe 7, and this air is introduced into the backwashing air diffuser pipes 81, 82, 83. It is discharged to remove the adhering sludge of the carrier. Further, the carrier is stirred by the discharged air, and the adhered sludge is removed from the carrier by this stirring.

[Processing restart process]
In the treatment restarting step, after the inspection, the connection between the air supply pipe 7 and the air supply machine is disconnected, the supply of the air is stopped, and the treatment of the sewage W is restarted. The treatment restart step is a step of restarting the normal operation of the sewage treatment device 1.

[advantage]
In the sewage treatment method, air is supplied to the sewage treatment device 1 only in the treatment start step and the inspection step, and the above air is not supplied in the treatment step as the normal operation of the sewage treatment device 1. Therefore, the sewage treatment method can reduce the cost of treating the sewage W. Further, in the sewage treatment method, since air is supplied to the anaerobic treatment carrier in the treatment start step to promote the activity of microorganisms, the operation start period of the sewage treatment device 1 is shortened and the sewage treatment is performed in a relatively short period of time. The device 1 can be put into normal operation. Further, in the sewage treatment method, the sludge in the final treatment tank 5 is returned to the first treatment tank 2 in the above inspection step, so that it is possible to suppress a decrease in the sewage treatment capacity. Therefore, the sewage W can be stably treated as treated water that meets the water quality standard.

[Other embodiments]
It should be considered that the disclosed embodiments are exemplary in all respects and not restrictive. The scope of the present invention is not limited to the configuration of the above embodiment, but is indicated by the scope of claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims. To.

In the above-described embodiment, the final treatment tank 5 has a settling section for precipitating suspended solids in the sewage W and a disinfecting section for disinfecting the supernatant of the sewage W. It may have a storage section for temporarily storing the sewage W and the disinfection section.

As described above, the sewage treatment apparatus, the sewage treatment unit, and the sewage treatment method of the present invention can stably perform sewage treatment at low cost, and are therefore suitably used as a sewage treatment facility or the like.

1 Sewage treatment equipment 11, 12, 13 partition walls 11a, 12a, 13a Outlet 14, 15, 16 Inspection port 17 Inlet 18 Outlet 2 First treatment tank 21 Bottom screen 22 Top screen 23 Flow path 3 Intermediate treatment tank (upstream) side)
31 Bottom screen 32 Top screen 33 Flow path 4 Intermediate treatment tank (downstream side)
41 Bottom screen 42 Top screen 5 Final treatment tank 6 Air lift pipe 7 Air supply pipe 81, 82, 83 Backwash diffuser pipe W Sewage

Claims (6)

A first treatment tank that treats sewage at least one of anaerobic treatment and solid-liquid separation,
One or more intermediate treatment tanks that anaerobicize the sewage treated by the first treatment tank, and
The intermediate treatment tank is equipped with a final treatment tank for anaerobic treatment or precipitation separation of treated sewage.
An air lift pipe having one end arranged at the bottom of the final treatment tank and the other end located at the top of the first treatment tank.
One end can be connected to an air supply machine disposed outside, the other end has a branched end, and this branched end is the first treatment tank, one or more intermediate treatment tanks. And with air supply pipes located in each of the final treatment tanks,
A sewage treatment device in which the end of the air supply pipe arranged in the final treatment tank is connected at one end side of the air lift pipe so that the air supplied from the air supply machine can be introduced into the air lift pipe. .. The sewage treatment apparatus according to claim 1, which does not have a treatment tank for aerobic treatment. The first treatment tank and one or more intermediate treatment tanks have a backwashing air diffuser for washing the carrier for anaerobic treatment.
Claim 1 or claim, wherein the ends of the air supply pipes arranged in the first treatment tank and one or more intermediate treatment tanks are connected so that the air can be introduced into the backwash air diffuser pipe. Item 2. The sewage treatment apparatus according to item 2. The final treatment tank has a backwashing air diffuser that is anaerobic and cleans the carrier for anaerobic treatment.
A claim in which the end of the air supply pipe arranged in the final treatment tank is branched and connected to the inside of the air lift pipe and the backwashing air diffuser of the final treatment tank so that the air can be introduced. Item 3. The sewage treatment apparatus according to Item 3. The sewage treatment apparatus according to any one of claims 1 to 4.
A sewage treatment unit provided with an air supply device that can be connected to the air supply pipe at the start of operation and inspection of the sewage treatment device. The method for treating sewage by the sewage treatment unit according to claim 5.
The process of arranging the above sewage treatment equipment and
The air supply machine is connected to the air supply pipe to supply air to at least the first treatment tank and one or more intermediate treatment tanks, and the sewage is treated by the first treatment tank, one or more intermediate treatment tanks. The process of starting the treatment by passing through the tank and the final treatment tank in this order,
The process of disconnecting the connection between the air supply pipe and the air supply machine, stopping the supply of the air, and treating the sewage.
The sewage treatment is interrupted, the air supply machine is connected to the air supply pipe, and air is supplied to at least one of the first treatment tank, the intermediate treatment tank and the final treatment tank to inspect the sewage treatment device. And the process of doing
A sewage treatment method comprising a step of disconnecting the connection between the air supply pipe and the air supply machine after the inspection, stopping the supply of the air, and restarting the treatment of the sewage.

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