JP2014161764A - Private sewage treatment tank including air lift pump and operational method of the private sewage treatment tank - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem in which: a combined private sewage treatment system having treatment object persons of 5-50 adopts a treatment mode in which anaerobic treatment and aerobic treatment are combined, and is mounted with a circulation function of transferring a part of aerobically treated treatment water to anaerobic treatment and further a cleaning function of transferring excess sludge generated by decomposing a suspended solids (SS) and a polluted matter captured in a filter bed of aerobic treatment to anaerobic treatment as cleaning waste water; an air lift pump that is inexpensive, simple structure and hardly breaks down is frequently employed for transferring circulation water and cleaning waste water, however, circulation water and cleaning waste water have different transfer water amounts, thereby there is a case in which transfer is performed by respective different air lift pumps, and cost is taken, and operation at a maintenance inspection time becomes complex.SOLUTION: In the present invention, circulation water and cleaning waste water can be transferred by the same air lift pump, so that cost reduction and reduction of maintenance inspection operation can be achieved.

Description

  The present invention relates to a sewage septic tank for treating domestic wastewater discharged from ordinary households and a method for operating the same.

  In a small-scale merged treatment septic tank corresponding to 5 to 50 people to be treated, many treatment methods combining anaerobic treatment and aerobic treatment have been seen (for example, Patent Document 1). The sewage septic tank that combines anaerobic treatment and aerobic treatment is an anaerobic treatment tank (anaerobic filter bed tank, precipitation separation tank, solid-liquid separation tank, etc.), aerobic treatment tank (contact aeration tank, carrier fluidization tank) in order from the upstream side. , Biological filtration tanks, etc.).

Such a small-scale merged treatment septic tank has a configuration in which a part of the treated water treated in the aerobic treatment tank is transferred to the anaerobic treatment tank as circulating water.
By transferring the circulating water to the anaerobic treatment tank, the treated water that has been treated in the anaerobic treatment tank can be transferred to the aerobic treatment tank and processed in the aerobic treatment tank even during the time period when there is no inflow of sewage. it can. Therefore, more efficient processing is possible than when there is no transfer of circulating water. Furthermore, the treated water transferred as circulating water contains nitrite nitrogen and nitrate nitrogen that have been nitrified in the aerobic treatment tank. When this treated water is transferred, the denitrification reaction is carried out in the anaerobic treatment tank. Therefore, nitrogen is removed from the treated water.
In view of these advantages, a function of transferring a part of the treated water in the aerobic treatment tank to the anaerobic treatment tank as circulating water is employed in a treatment method combining anaerobic treatment and aerobic treatment.

By the way, in biological treatment, purification proceeds by converting pollutants such as organic matter contained in sewage into organisms regardless of anaerobic treatment or aerobic treatment. Therefore, it is necessary to draw out the biologically increased organisms, that is, excess sludge, outside the treatment tank.
In particular, in an aerobic treatment tank where the growth rate of microorganisms is high, the amount of conversion to organisms is larger than in an anaerobic treatment tank. In a small-scale merged treatment septic tank that corresponds to 5 to 50 people to be treated, the biofilm attached to the filter medium of the aerobic treatment tank is thickened, and thus cleaning that periodically peels off the biofilm is necessary. In recent years, the number of cases in which a biological filtration tank is employed as an aerobic treatment tank is increasing. In biological filtration tanks, the carrier (filter material) packed in the filter bed in the tank captures suspended solids (SS) in the treated water, so the filter bed should be washed periodically to prevent clogging. Is required. The filter bed can be washed by peeling off the attached biofilm or suspended solids by aeration.

In a sewage septic tank that combines anaerobic treatment and aerobic treatment, the separated biofilm or suspended matter is transferred to and stored in an anaerobic treatment tank serving as a sludge reservoir as washing wastewater. In the anaerobic treatment tank, the growth rate of the organism is slow, so that the sludge containing the washing waste water is stored while being slowly digested. And the sludge stored in the anaerobic treatment tank is finally at the time when the sludge in the anaerobic treatment tank reaches the storage limit or the cleaning frequency (once a year) stipulated in the Septic Tank Law is reached. Pulled out.
In this way, in the sewage septic tank having a treatment system that combines anaerobic treatment and aerobic treatment, the function of transferring the biofilm thickened in the aerobic treatment tank and the suspended solids captured by the filter bed to the anaerobic treatment tank as washing wastewater Is adopted.

  As described above, in the small-scale merged treatment septic tank having 5 to 50 persons to be treated, circulating water and washing waste water are transferred from the aerobic treatment tank to the anaerobic treatment tank. As a means of transport, an air lift pump is adopted from a practical viewpoint, which has few failures, has a simple structure, is easy to maintain, and is inexpensive.

Japanese Patent Laid-Open No. 9-248484

  If the amount of circulating water is too small, the processing efficiency will decrease and the quality of the treated water will deteriorate, but conversely, if too much, the sludge stored in the anaerobic treatment tank as the transfer destination will be rolled up, Sludge flows out into the aerobic treatment tank and the quality of the treated water is lowered. Therefore, it is important to set the amount of circulating water to an appropriate amount, and 3 to 4 times the appropriate amount for the inflowing water amount (daily average sewage amount). When converted in a 5-person tank, the appropriate amount of circulating water is 3,000 to 4,000 L per day. Corresponds to 2.8 L / min.

  There is an appropriate amount of washing wastewater as well as the amount of circulating water. Washing the filter bed is an act of diffusing the thickened biofilm and suspended solids trapped in the filter bed by aeration, etc., and inflow to minimize the effect on processing performance. It is set to be implemented in a short period of time such as late at night when there is little sewage. The transfer amount of cleaning wastewater varies depending on the type and capacity of the adopted aerobic treatment tank, the amount of filter medium filled, the washing speed (washing wastewater amount per sectional area of the aerobic treatment tank), etc. 10 L / min.

  Thus, since the appropriate amounts of water transferred for the circulating water and the cleaning wastewater are different, the air lift pumps for transferring the circulating water and the cleaning wastewater have been conventionally installed separately. As a result, there is a problem that the structure becomes complicated, the cost increases, and the labor for maintenance and inspection increases.

  This invention is made | formed in view of said subject, and it aims at provision of the sewage septic tank provided with the air lift pump which transfers the circulating water and washing waste_water | drain from which the amount of transferred water differs with one air lift pump.

The present invention relates to the following.
(1) A sewage septic tank having a pretreatment tank and an aerobic treatment tank disposed in a subsequent stage, wherein the aerobic washing apparatus cleans the filter bed of the aerobic treatment tank with aeration, and the aerobic treatment A part of the treated water disposed in the tank or in the subsequent stage and treated in the aerobic treatment tank is transferred to the former treatment tank as circulating water, and the washing wastewater generated by the washing by the aeration washing apparatus is treated in the former treatment tank. An air lift pump for transferring to the pump, and the air lift pump supplies the air necessary for pumping the circulating water connected to the pumping pipe and a pumping pipe serving as a transfer path for the circulating water and washing waste water. And a second air pipe connected to the pumping pipe and supplying air necessary for pumping the washing waste water.
(2) The sewage septic tank according to item (1), wherein an orifice or an air adjustment valve for adjusting the amount of air supplied into the path of the first air pipe is provided.
(3) The sewage septic tank according to item (1) or (2), wherein an orifice or an air adjustment valve for adjusting the amount of air supplied into the path of the second air pipe is provided.
(4) The opening portion of the second air pipe is formed at a position deeper than the opening portion of the first air pipe. According to any one of items (1) to (3), Sewage septic tank.
(5) The sewage septic tank according to any one of (1) to (4), wherein a diameter of the second air pipe is larger than a diameter of the first air pipe. .
(6) The sewage septic tank according to any one of (1) to (5), wherein the front-stage treatment tank is an anaerobic treatment tank.
(7) A method for operating a sewage septic tank having a pre-treatment tank and an aerobic treatment tank disposed in a subsequent stage, wherein the sewage septic tank is configured to aerate the filter bed of the aerobic treatment tank with aeration. A cleaning device and a part of the treated water disposed in the aerobic treatment tank or in the subsequent stage and transferred in the aerobic treatment tank are transferred to the preceding treatment tank as circulating water, and washed by the aerobic washing device. An air lift pump for transferring the generated cleaning wastewater to the pretreatment tank, and the air lift pump serves as a transfer path for the circulating water and the cleaning wastewater, and a first air pipe connected to the pumping pipe. And by supplying air to the first air pipe, pumping the circulating water, supplying air to the aeration cleaner and supplying air to the second air pipe. The washing waste water The method of operating septic tank, characterized by water.

The sewage purification tank of the present invention has an air lift pump that transfers circulating water and washing waste water from the aerobic treatment tank or from the subsequent stage to the front treatment tank. The air lift pump is connected to the pumping pipe and the pumping pipe. Two systems of air piping (first air piping and second air piping) are connected.
Therefore, by supplying the air for transferring the circulating water or the air for transferring the cleaning wastewater to these two air pipes, respectively, the transport water having an appropriate amount of water as the circulating water or the cleaning wastewater is pre-treated. Can be transferred to the tank. That is, since the circulating water and the washing waste water can be transferred by one air lift pump, the structure becomes simple, the cost is reduced, and the maintenance and inspection work can be reduced.
In addition, washing wastewater with a larger amount of transferred water than circulating water is periodically passed through the air lift pump, so that the thickening of the biofilm can be suppressed inside the pumping pipe, and the amount of circulating water transferred can be stabilized. Can be

BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic of 1st Example of the wastewater septic tank of this invention, Fig.1 (a) is a top view, FIG.1 (b) is a cross-sectional view, FIG.1 (c) is a longitudinal cross-sectional view. . It is a figure which shows the air lift pump employ | adopted for the sewage septic tank of this invention, and FIG. 2 (a)-FIG. It is a schematic diagram which shows the air supply part employ | adopted as the air lift pump of 1st Example in the wastewater septic tank of this invention, Fig.3 (a) shows the outline of an air supply part, FIG.3 (b) shows air. The outline of a supply amount adjustment mechanism is shown. It is a schematic diagram which shows the modification of the air supply part shown in FIG.

  An anaerobic treatment tank is preferably used as the pre-stage treatment tank described in the present invention. The anaerobic treatment tank is not particularly limited as long as it has a solid-liquid separation function and a sludge storage function. Specifically, a precipitation separation tank, an anaerobic filter bed tank, and the like can be used. .

  When the anaerobic treatment tank has a filter bed, the filter bed may be suitably filled with a filter medium having a low trapping property, such as a filter medium regularly packed in a plate shape, a net-like plate shape, or a net-like cylindrical shape. it can. The filter medium having a weak trapping property prevents sludge from accumulating on the upper part of the filter bed, and prevents sludge from becoming scum and flowing out to the next tank. And the installation position (upper surface position) of a filter medium can also be made into the position close | similar to the water surface above a solid-liquid separation tank, since sludge does not accumulate easily in the filter bed upper part.

In addition, when there is no filter bed inside the anaerobic treatment tank, the solid-liquid separation tank should be disconnected in consideration of the water area load so that solids or sludge is separated from the treated water by sedimentation and floating. It is preferable to secure an area and arrange an inflow pipe and an outflow pipe in the middle portion when viewed in the vertical direction.
Further, the anaerobic treatment tank can be divided into two chambers, and a precipitation separation tank and an anaerobic filter bed tank can be used in combination. In recent years, as shown in Japanese Patent No. 4702748, an aerobic sludge storage part has been devised that is incorporated in a sedimentation separation tank. In the present invention, an aerobic sludge storage part is also anaerobic. It is also possible to combine with a processing tank.

The aerobic treatment tank described in the present invention includes a filter bed, and the filter bed is filled with a filter medium (including a carrier) for inhabiting microorganisms that contribute to the treatment of treated water. There is no particular limitation as long as dissolved oxygen can be supplied to the filter medium, and specifically, a contact aeration tank, a biological filtration tank, or the like can be used.
The aerobic treatment tank can be divided into two chambers, and a contact aeration tank and a biological filtration tank can be used in combination.

  The air lift pump for transferring circulating water and washing waste water according to the present invention includes a pumping pipe, two air pipes connected to the pumping pipe (first air pipe and second air pipe), and the two air pipes. And an air supply device for supplying air. Of the two air pipes, the first air pipe is supplied with air for transferring the circulating water, and the second air pipe is supplied with air for transferring the washing waste water. By having such a structure, it becomes possible to transfer circulating water and washing waste water with one air lift pump. In addition, washing wastewater with a larger amount of transferred water than circulating water is periodically passed through the air lift pump, so that the thickening of the biofilm can be suppressed inside the pumping pipe, and the amount of circulating water transferred can be stabilized. Can be

  There are two methods for connecting the pumping pipe and each air pipe: a method of connecting to the outside of the pumping pipe and a method of connecting to the inside of the pumping pipe so as to be doubled. As exemplified in (a) to (e), the respective methods can be used in combination (details will be described later in Examples). In addition, the immersion depth of the air pipe (distance from the water surface to the opening of the air pipe), the pipe diameter of the pumping pipe, and the pipe diameter of the air pipe should be appropriately selected according to the amount of circulating water or cleaning wastewater transferred. Furthermore, it is possible to obtain a predetermined amount of circulating water and cleaning drainage by supplying an amount of air corresponding to the amount of water transferred to each air pipe.

Each air pipe is preferably provided with an orifice or an air adjustment valve in order to adjust the amount of air, so that the amount of air supplied to each air pipe can be directly adjusted. In particular, an appropriate amount of circulating water can be transferred by providing an orifice and an air adjustment valve in the first air pipe that supplies air for transferring the circulating water.
Japanese Patent Laid-Open No. 11-676 discloses a circulating air lift pump in which two air pipes are connected to a pumping pipe. This circulating air lift pump is provided with a throttle at the suction port in order to adjust the amount of circulating water to a small amount, and the passage through which the pumped water passes becomes narrow by providing the throttle, so that it is blocked by sludge and biological membranes. In order to prevent this, the air is intermittently washed with the air supplied from the second air pipe.
In the present invention, when an orifice or an air adjustment valve is provided in the first air pipe, it is possible to transfer an appropriate amount of circulating water by supplying an appropriate amount of air, so it is necessary to provide a throttle at the suction port. There is no.
The above prior art is for solving the problem caused by providing the throttle part in the suction port, and the premised technique is different from the present invention. The sewage septic tank of the present invention has two types (circulated water and washing waste water) and is intended to transfer waste water having different amounts of water with a single air lift pump, which is completely different from the above-described prior art in purpose and effect. It can be said that.

  The suction port of the air lift pump of the present invention can transfer a part of the treated water treated in the aerobic treatment tank to the upstream treatment tank as circulating water, and further, the washing drainage of the filter bed of the aerobic treatment tank to the upstream stage. If it can transfer to a processing tank, it will not be restrict | limited especially, You may connect to an aerobic processing tank directly, or you may connect to the processing water tank and precipitation tank which are provided in the post process of an aerobic processing tank. However, when connecting to a treatment water tank or a sedimentation tank, since it will become inefficient to transfer cleaning waste water when it is far from the aerobic treatment tank, it is preferable to be close to the advection port of the aerobic treatment tank.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig.1 (a)-(c) shows the schematic sectional drawing of the wastewater septic tank 1 which concerns on 1st Example of this invention.
A sewage purification tank 1 shown in FIGS. 1A to 1C includes an anaerobic treatment tank (pre-treatment tank) 30 in order from the upstream side inside a tank structure constituted by a peripheral wall 1A, a bottom wall 1B, and a ceiling wall 1C. An aerobic treatment tank 31, a treated water tank 6, and a disinfection tank 7 are arranged.
In the sewage septic tank 1, an inlet 24 is formed at one end on the inlet side, an outlet 23 is formed at one end on the outlet side, and partition walls 1D and 1E are formed at intervals from the inlet 24 side to the outlet 23 side. Yes. Moreover, the anaerobic treatment tank 30 side and the aerobic treatment tank 31, the treated water tank 6, and the disinfection tank 7 side are divided by the partition wall 1E.

As the anaerobic treatment tank 30, an anaerobic filter bed tank is adopted, and the anaerobic treatment tank 30 is divided into an anaerobic filter bed tank first chamber 2 and an anaerobic filter bed tank second chamber 3 from the upstream side by a partition wall 1D. .
Furthermore, as shown to Fig.1 (a), the partition walls 1F and 1G are formed in the downstream of the partition wall 1E so that it may parallel, and the area | region partitioned by the partition walls 1F and 1G is a partition wall. A partition wall 1H is provided so as to be orthogonal to 1F and 1G. By the partition walls 1F, 1G, and 1H, the downstream side of the partition wall 1E is divided into four tanks, and two tanks from the upstream side are the aerobic treatment tanks 31. An aerobic filter bed tank is employed as the aerobic treatment tank 31 and is divided into a contact aeration unit 4 and a biological filtration unit 5 from the upstream side. Further, a treated water tank 6 and a disinfecting tank 7 are arranged at the subsequent stage of the aerobic treatment tank.

The anaerobic filter bed first chamber 2 is divided into a filter bed 8 and an advection section 25 by a partition wall 8B. Above and below the filter bed 8, there are provided filter medium outflow prevention plates 8A and 8A through which the treated water is passed, although the mesh-like cylindrical filter medium filled as a filter medium is not passed.
Similarly, the second chamber 3 of the anaerobic filter bed tank is divided into the filter bed 9 and the advection section 26 by the partition wall 9B, and the skeletal spherical filter medium filled as the filter medium is not passed above and below the filter bed 9. In addition, filter medium outflow prevention plates 9A and 9A through which treated water is passed are provided.
By passing the treated water through these filter beds 8 and 9, solids contained in the treated water (sewage) are captured, and further, microorganisms attached to the mesh-like cylindrical filter medium and the skeletal spherical filter medium cause Decompose organic substances and trapped solids.
In the first chamber 2 of the anaerobic filter bed tank, a scum storage part 2a is provided above the filter bed 8 for storing sludge floating together with gas generated by biological reaction as scum. The sludge storage part 2b which stores the sludge which became fine and settled as deposited sludge is provided.
Similarly, in the second chamber 3 in the anaerobic filter bed tank 3, a scum storage part 3 a is provided above the filter bed 9 to store sludge floating together with gas generated by biological reaction as scum. A sludge storage portion 3b is provided for storing the sludge that has become fine and settled as accumulated sludge.

As shown in FIGS. 1A and 1B, the flow rate adjusting device 10 is provided in the advection section 26 of the second chamber 3 of the anaerobic filter bed tank. As the flow rate adjusting device 10 of the present embodiment, a combination of an air lift pump and a flow rate adjusting mass (distribution mass) can be adopted.
In addition, as a space to be stored when a large amount of water flows in a short time, such as bathtub drainage, the anaerobic treatment tank 30 (anaerobic filter bed tank first chamber 2 and anaerobic filter bed tank second chamber 3). A flow rate adjusting unit 11 is provided in the upper part.
The sewage subjected to the anaerobic treatment in the anaerobic treatment tank 30 is transferred by the flow rate adjusting device 10 to the contact aeration unit 4 of the aerobic treatment tank 31. The amount of sewage stored in the anaerobic treatment tank 30 by adjusting the amount of sewage transferred by the flow rate adjusting device 10 is shown in FIG. W. From L (low water level) to H. W. Sewage treatment can be performed while adjusting during L (high water level). That is, it becomes possible to temporarily store the treated water in the flow rate adjusting unit 11, and to reduce the load of the influent water (flow rate adjusting function or peak cut function).
In addition, although the sewage septic tank 1 of a present Example has a flow volume adjustment function, the sewage septic tank of this invention does not have a flow volume adjustment apparatus, but is very good.

The aerobic treatment tank (aerobic filter bed tank) 31 includes a contact aeration unit 4 and a biological filtration unit 5. As shown in FIG. 1 (c), advection ports 12 and 13 are provided at the upper and lower portions of the partition wall 1 F that separates the contact aeration unit 4 and the biological filtration unit 5, respectively. The treated water is circulated between the contact aeration unit 4 and the biological filtration unit 5.
The contact aeration unit 4 of the aerobic treatment tank 31 is provided with a filter bed 27 and filled with a loofah-like plate-shaped filter medium as a filter medium. An aeration tube 14 is installed at the bottom of the contact aeration unit 4, and the contact aeration unit 4 is in an aeration state during normal processing.

The biological filtration unit 5 of the aerobic treatment tank 31 is provided with a filter bed 16 and filled with a granular carrier as a filter medium. If the normal operation is continued, the particulate carrier of the filter bed 16 is clogged by the trapped suspended solids and the grown biofilm, so that the filter bed 16 needs to be periodically cleaned. An aeration tube (aeration washing device) 15 is installed at the bottom of the biological filtration unit 5. By supplying air from the aeration tube 15 (backwashing), the trapped suspended matter and the biofilm are in a granular carrier. It will be peeled off and flow.
Moreover, the advection port 17 is provided in the lower part of the partition wall 1G which separates the process water tank 6 of the back | latter stage, and the contact aeration part 4 of the aerobic treatment tank 31. As shown in FIG.

The treated water tank 6 stores the effluent water (treated water) from the biological filtration unit 5 of the aerobic treatment tank 31 and serves as a conduit for reaching the disinfection tank 7 at the subsequent stage. Further, the disinfection tank 7 contacts the chlorinated solid disinfectant contained in the chemical cylinder with the treated water transferred from the treated water tank 6 and reacts in the disinfecting tank 7, and then the outside of the wastewater purification tank 1 from the outlet 23. It has come to leak.
The treated water tank 6 is provided with an air lift pump 18A for transferring the stored treated water to the first chamber 2 of the anaerobic filter bed tank of the anaerobic treatment tank 30. The air lift pump 18 </ b> A is provided to transfer the circulating water and the washing waste water from the treated water tank 6 to the anaerobic filter bed tank first chamber 2.

  By transferring the treated water stored in the treated water tank 6 to the anaerobic treatment tank 30 as circulating water, it facilitates the transfer of treated water from the anaerobic treatment tank 30 to the aerobic treatment tank 31 even in a time zone where there is no inflow of sewage, Sewage can be treated efficiently. Further, since the treated water transferred as circulating water contains nitrite nitrogen and nitrate nitrogen that have been nitrified in the aerobic treatment tank 31, a denitrification reaction occurs in the anaerobic treatment tank 30 and nitrogen is removed from the treated water. Can be removed.

  In the biological filtration part 5 of the aerobic treatment tank 31, in order to prevent clogging due to suspended substances and biological membranes, it is necessary to periodically clean the filter bed 16 by aeration. The suspended matter and biofilm separated from the filter bed 16 by washing are transferred to the anaerobic treatment tank 30 by the air lift pump 18A as washing waste water.

FIG. 2 (a) shows a schematic diagram of an air lift pump 18A provided in the sewage septic tank 1 of the first embodiment of the present invention.
The air lift pump 18A includes a pumping pipe 21 serving as a transfer path for circulating water and cleaning waste water, a first air pipe 20A and a second air pipe 22A connected to the pumping pipe 21, respectively, and the first air pipe 20A and the first air pipe 20A. It is mainly composed of an air supply device 40 (see FIG. 3A) for supplying air to the two-air pipe 22A.

The pumping pipe 21 is composed of a vertical pumping portion 21a extending in the vertical direction and a horizontal introduction portion 21c connected to the vicinity of the upper portion 21b of the vertical pumping portion 21a.
As shown in FIGS. 1 (a) to (c), a suction port 19 is provided at the lower end of the vertical pumping portion 21a, and the circulating water or washing waste water in the treated water tank 6 is sucked from the suction port 19, Water is pumped through the vertical pumping section 21a extending vertically along the partition walls 1E and 1G. The pumped circulating water or washing wastewater passes through the horizontal introduction part 21c formed across the partition walls 1E and 1A, and is transferred to the filter bed 8 in the first chamber 2 of the anaerobic filter bed tank of the anaerobic treatment tank 30.
The suction port 19 of the air lift pump 18 </ b> A is disposed in the vicinity of the advection port 17 connected to the biological filtration unit 5 of the aerobic treatment tank 31 in the treated water tank 6. The suction port 19 is preferably positioned as close as possible to the advection port 17 in order to more reliably suck the suspended matter contained in the cleaning wastewater and transfer it to the anaerobic treatment tank 30.

  As shown to Fig.2 (a), the 1st air piping 20A is connected to the air lift pump 18A in a present Example from the upper part 21b of the vertical pumping part 21a. The first air pipe 20 </ b> A extends downward so as to be installed in the vertical pumping portion 21 a of the pumping pipe 21, and constitutes an opening 20 a above the suction port 19 of the pumping pipe 21 and below the water surface. Further, the second air pipe 22A of the air lift pump 18A is a side part of the vertical pumping part 21a of the pumping pipe 21 and below the opening part 20a of the first air pipe 20A, and from the suction port 19 of the pumping pipe 21. An opening 22a is formed and connected to the upper region.

Air necessary for pumping the circulating water is supplied to the first air pipe 20A. Further, the air necessary for pumping the cleaning waste water is supplied to the second air pipe 22A.
When air is supplied from the first air pipe 20A or the second air pipe 22A, the air rises as bubbles inside the vertical pumping portion 21a of the pumping pipe 21. At this time, the circulating water or the washing waste water located above the bubbles is pushed up by the air, rises in the vertical pumping portion 21a together with the bubbles, and reaches the connection portion with the horizontal introduction portion 21c. Furthermore, it advances along the horizontal introduction part 21c with air, and is discharged above the filter bed 8 in the anaerobic filter bed tank first chamber 2 of the anaerobic treatment tank 30.
In addition, the bubbles rise in the vertical pumping portion 21a of the pumping pipe 21, and new treated water (circulated water or washing drainage) is drawn from below the suction port 19.

  In normal operation, that is, in an operation state in which part of the treated water stored in the treated water tank 6 is periodically circulated as circulating water, air is supplied to the first air pipe 20A and air is supplied to the second air pipe 22A. Without operating the air lift pump 18A. Thereby, circulating water flows through the air lift pump 18 </ b> A, and the circulating water is transferred to the first chamber 2 of the anaerobic filter bed tank of the anaerobic treatment tank 30.

  When the filter bed 16 of the biological filtration unit 5 in the aerobic treatment tank 31 is washed, aeration is performed by an air diffuser (aeration washing device) 15 installed at the bottom of the biological filtration unit 5, and the filter bed 16 is then aerated. The attached suspended matter and biofilm are peeled off (see FIG. 1C), and at the same time, air is supplied to the second air pipe 22A without supplying air to the first air pipe 20A, and the air lift pump 18A is operated. . The suspended solids and biofilm separated by aeration are sucked from the suction port 19 of the air lift pump 18A together with a part of the treated water, and transferred to the filter bed 8 in the first chamber 2 of the anaerobic filter bed 30 of the anaerobic treatment tank 30. Is done.

By the way, the optimum amount of transferred water per unit time differs between the circulating water and the washing waste water. As an example, when converted in a 5-person tank, it is appropriate that the circulating water is 2.1 to 2.8 L / min, and the washing wastewater is appropriate to be several tens of L / min.
Based on the design theory of the air lift pump, the first air pipe 20A and the second air pipe 22A are arranged from the water surface to the openings 20a and 22a of the first and second air pipes 20A and 22A so as to have the above-mentioned transfer water amount. The parameters such as the immersion depths h ₁ and h ₂ , the pipe diameters d ₁ and d _{2 of} the first and second air pipes 20A and 22A, and the pipe diameter D of the vertical pumping portion 21a of the pumping pipe 21 are appropriately set. .

Next, the air supply unit 50 that supplies air from the air supply device 40 to the first air pipe 20A and the second air pipe 22A will be described with reference to FIG.
As shown in FIG. 3A, the first and second air pipes 20 </ b> A and 22 </ b> A are connected to the air supply device 40. Air supply amount adjustment mechanisms 41 and 42 are provided in the middle of the first and second air pipes 20A and 22A, respectively.
In this embodiment, the air supply amount adjustment mechanism 41 provided in the first air pipe 20A is composed of an orifice 41a and an air adjustment valve 41b, as shown in FIG. The supply amount is greatly adjusted, and further fine adjustment is performed by the air adjustment valve 41b.
Similarly, the air supply amount adjusting mechanism 42 provided in the second air pipe 22A includes an orifice 42a and an air adjusting valve 42b.

As described above, the pumping amount per unit time of washing wastewater is larger than the pumping amount per unit time of circulating water (circulating water is 2.1 to 2.8 L / min when converted by a 5-person tank, It is appropriate to drain several tens of liters per minute. In order to pump up the circulating water, the first air pipe 20A is used as a route, and the amount of air per unit time supplied to the pumped pipe 21 is used to pump the cleaning wastewater, and the second air pipe 22A is used as a route. The amount of pumped water per unit time between the circulating water and the washing waste water can be changed by increasing the amount of air supplied per unit time.
Therefore, the air supply amount adjustment mechanism 42 (that is, the orifice 42a and the orifice 42a and the air adjustment valve 41b) that is provided in the second air piping 22A is different from the air supply amount adjustment mechanism 41 (that is, the orifice 41a and the air adjustment valve 41b) that is provided in the first air piping 20A. The air regulating valve 42b) has a structure that allows more air to flow. Specifically, the orifice 42a of the air supply amount adjusting mechanism 42 is formed to have a larger hole diameter than the orifice 41a of the air supply amount adjusting mechanism 41 so that more air flows.

The air supply amount adjustment mechanisms 41 and 42 provided in the first and second air pipes 20A and 22A can be either an orifice or an air adjustment valve as long as the amount of air supplied to the pumping pipe 21 can be appropriately controlled. Or one.
Further, when the output of the air supply device 40 matches the supply amount for pumping the cleaning waste water, the second air pipe 22A is not provided with the air supply amount adjusting mechanism 42, and the first air pipe 20A. The air supply amount adjusting mechanism 41 may be provided only in the case.

As the air supply device 40, a diaphragm type blower can be preferably used.
First and second air pipes 20A and 22A are connected to the air supply device 40, respectively. The air supply device 40 is provided with a switching valve 40a, and the air supply destination can be switched to either the first air pipe 20A or the second air pipe 22A. As the switching valve 40a, an electromagnetic valve, an electric valve or the like can be employed.

The switching valve 40a is connected to the switching valve control unit 40b. The switching valve control unit 40b has, for example, a timer function. When a predetermined time elapses, the switching valve control unit 40b causes the switching valve 40a to function, and the air supply device 40 switches the air piping through which the air is supplied, thereby increasing the pumping amount of the air lift pump 18A. It can be changed.
In addition, it is preferable to perform control of the switching valve 40a by the switching valve control part 40b synchronizing with the blower which sends air to the diffuser tube (aeration washing | cleaning apparatus) 15 shown to FIG.1 (b), (c). That is, air is sent to the air diffusion pipe 15 to clean the filter bed 16, and at the same time, the switching valve 40a is operated to supply air to the pumping pipe 21 through the second air pipe 22A. This makes it possible to immediately transfer the cleaning wastewater generated by the cleaning. Further, simultaneously with stopping the supply of air to the air diffuser 15, by operating the switching valve 40 a, the supply of air to the pumped water pipe 21 through the second air pipe 22 </ b> A is stopped, and the first air pipe 20 </ b> A is connected. Switching to air supply to the pumped water pipe 21 serving as a path can start the transfer of circulating water in a normal operation state.

In FIG. 4, the air supply part 51 which is a modification of the air supply part 50 mentioned above is shown. The air supply unit 51 of the modification has a configuration including two air supply devices 43 and 44. That is, the first air supply device 43 is connected to the first air pipe 20A, and the second air supply device 44 is connected to the second air pipe 22A. The first and second air supply devices 43 and 44 are electrically connected to the air supply device controller 45. The air supply device control unit 45 has, for example, a timer function, and can switch the operation of the first and second air supply devices 43 and 44 to change the pumping amount of the air lift pump 18A when a certain time elapses. it can.
However, in the air supply unit 51 of the modified example, two air supply devices 43 and 44 are required. Accordingly, in consideration of cost, the first air pipe 20A and the second air pipe 22A are connected to one air supply device 40 that supplies constant air, and the air supply path can be switched by the switching valve 40a. It is desirable to employ three air supply units 50.

As a result, the air supply device 40 sends an air amount corresponding to the amount of circulating water and cleaning water transferred from the opening 20a or the opening 22a through the first air pipe 20A or the second air pipe 22A as a route. A predetermined amount of transferred water can be obtained. Further, in the middle of the path of the first and second air pipes 20A and 22A, air supply amount adjustment mechanisms 41 and 42 (orifices or air adjustment valves) for adjusting the amount of air to be supplied are provided, so that the circulating water and the washing are cleaned. The amount of discharged water can be adjusted.

2B to 2E show air lift pumps 18B, 18C, 18D, and 18E of second to fifth embodiments that can be employed in the sewage septic tank 1 according to the present invention.
In the air lift pumps 18B, 18C, 18D, and 18E of the second to fifth embodiments shown in FIGS. 2B to 2E, the same components as those of the air lift pump 18A of the first embodiment are denoted by the same reference numerals. A description of the same elements is omitted. In these air lift pumps 18B, 18C, 18D, and 18E, the air supply units 50 and 51 described with reference to FIGS. 3 and 4 can be employed as the air supply unit including the air supply device 40.
The air lift pumps 18B, 18C, 18D, 18E of the second to fifth embodiments have a difference in the configuration of the first and second air pipes as compared with the air lift pump 18A of the first embodiment.

  In the air lift pump 18B of the second embodiment shown in FIG. 2B, both the first and second air pipes 20B and 22B are connected from the upper part 21b of the vertical pumping part 21a of the pumping pipe 21, and are connected to the vertical pumping part 21a. It extends downward so as to be installed, and constitutes openings 20a and 22a above the suction port 19 of the pumping pipe 21 and below the water surface. The opening 20a of the first air pipe 20B is formed above the opening 22a of the second air pipe 22B.

  In the air lift pump 18C of the third embodiment shown in FIG. 2 (c), the first and second air pipes 20C, 22C are both sides of the vertical pumping section 21a of the pumping pipe 21, and are the suction ports of the pumping pipe 21. Openings 20a and 22a are formed and connected above 19 and below the water surface. The opening 20a of the first air pipe 20C is formed above the opening 22a of the second air pipe 22C.

  In the air lift pump 18D of the fourth embodiment shown in FIG. 2 (d), the first and second air pipes 20D and 22D join at a joining point 33D and are connected to the pumped pipe 21 as a joining pipe 32D. The merge pipe 32D is connected from the upper part 21b of the vertical pumping part 21a of the pumping pipe 21, extends downward so as to be embedded in the vertical pumping part 21a, and opens above the suction port 19 of the pumping pipe 21 and below the water surface. 32a is constituted.

  In the air lift pump 18E of the fifth embodiment shown in FIG. 2 (e), the first and second air pipes 20E and 22E join at a confluence point 33E as in the air lift pump 18D of the fourth embodiment and join pipe 32E. As shown in FIG. The merge pipe 32E is connected to the side of the vertical pumping portion 21a of the pumping pipe 21 by forming an opening 32a above the suction port 19 of the pumping pipe 21 and below the water surface.

In the air lift pumps 18B and 18C of the second and third embodiments described based on FIGS. 2B and 2C, the immersion depth h ₁ of each air pipe is similar to the air lift pump 18A of the first embodiment. By appropriately selecting parameters such as h ₂ , the pipe diameters d ₁ and d _{2 of} each air pipe, and the pipe diameter D of the vertical pumping section 21a, a predetermined amount of transferred water corresponding to the circulating water and the washing waste water can be obtained. . Similarly to the air lift pump 18A of the first embodiment, an orifice and an air adjustment valve (air supply amount adjustment mechanisms 41 and 42) for adjusting the amount of air sent along the path of each air pipe can be provided.

In the air lift pumps 18D and 18E of the fourth and fifth embodiments described based on FIGS. 2D and 2E, the first and second air pipes 20D and 22D (or 20E and 20E) are joined at a junction 33D (33E). ) And is connected to the pumped water pipe 21 as a joining pipe 32D (32E).
Therefore, the air lift pumps 18D and 18E of the fourth and fifth embodiments have the immersion depth h ₃ that is the distance from the water surface to the opening 32a of the merge pipe 32D (32E), the first and second air pipes 20D and 22D (or 20E, 20E) by appropriately selecting parameters such as the pipe diameters d ₁ and d ₂ , the pipe diameter d _{3 of} the merging pipe 32D (32E), the pipe diameter D of the vertical pumping portion 21a of the pumping pipe 21, and the like. It can be designed so that the amount of each of the circulating water and the washing wastewater is transferred.
Similarly to the air lift pump 18A of the first embodiment, an orifice for adjusting the amount of air to be supplied and an air adjustment valve (air supply amount adjustment mechanisms 41, 42) can be provided. In this case, the junction 33D (33E) ) By supplying it in the middle of the path of the previous first and second air pipes 20D and 22D (or 20E and 20E), air corresponding to the circulating water and the washing waste water is supplied from the opening 32a of the merge pipe 32D (32E). can do.

Next, a process for treating treated water (sewage) will be described.
First, the treated water flows into the first chamber 2 in the anaerobic filter bed tank inside the sewage purification tank 1 through the inflow port 24. In the first chamber 2 of the anaerobic filter bed, when the treated water passes through the filter bed 8, solid matter is captured, organic matter is decomposed by microorganisms adhering to the filter bed 8, nitrite nitrogen and nitrate nitrogen. Denitrification is performed. The treated water treated in the anaerobic filter bed first chamber 2 is transferred to the advection section 25 and is transferred to the anaerobic filter bed second chamber 3.

  In the second chamber 3 of the anaerobic filter bed tank, as in the first chamber 2 of the anaerobic filter bed tank, the solid matter is captured, the organic matter is decomposed by the microorganisms adhering to the filter bed 9, and nitrite nitrogen and nitrate nitrogen. Denitrification is performed. The treated water treated in the anaerobic filter bed second chamber 3 is transferred to the advection section 26 and is transferred to the aerobic treatment tank 31 via the flow rate adjusting device 10. In the transfer by the flow control device 10, the amount of water is limited, and when there is a peak inflow such as bathtub drainage, the treated water that could not be transferred due to the limitation is anaerobic filter bed first chamber 2 and anaerobic. It is temporarily stored in the flow rate adjusting unit 11 provided on the upper part of the filter beds 8 and 9 in the second filter bed chamber 3. The stored treated water is sequentially transferred to the aerobic treatment tank 31 by the flow rate adjusting device 10 after the peak inflow is finished.

  The treated water transferred to the aerobic treatment tank 31 is subjected to the circulation treatment of the contact aeration unit 4 and the biological filtration unit 5. The filter bed 27 of the contact aeration unit 4 is filled with a loofah-like plate-shaped filter medium so that it opens up and down, and the inside of the contact aeration unit 4 is formed by the air supplied from the diffuser pipe 14 installed at the bottom. When the microorganisms adhering to the loofah-like plate-shaped filter medium of the filter bed 27 come into contact with the treated water, decomposition of organic matter (BOD) and nitrification of ammonia nitrogen proceed.

  The treated water treated in the contact aeration unit 4 is sequentially transferred from the upper transfer port 12 to the biological filtration unit 5. The filter bed 16 of the biological filtration unit 5 is filled with a granular carrier having a specific gravity slightly larger than 1, and carrier discharge prevention plates 28 and 29 for passing the treated water are disposed above and below the granular carrier, but the granular carrier is not passed therethrough. It is. In normal operation, since the aeration from the diffuser 15 installed at the bottom of the biological filtration unit 5 is not performed, the filter bed 16 is formed in a state where the granular carrier settles on the lower carrier outflow suppression plate 29 side. . The treated water passes through the filter bed 16 in a downward flow and comes into contact with microorganisms attached to the filter bed 16, whereby decomposition of organic matter (BOD) and nitrification of ammonia nitrogen proceed. At the same time, suspended substances contained in the treated water are captured by the filter bed 16 and the treated water is clarified.

  The treated water treated in the biological filtration unit 5 is re-transferred from the lower advection port 13 to the contact aeration unit 4 and repeatedly subjected to the treatment in the contact aeration unit 4 and the treatment in the biological filtration unit 5. Become. The treated water thus subjected to the circulation treatment in the aerobic treatment tank 31 is equivalent to the amount of transferred water from the flow rate adjusting device 10 (the amount of circulating water transferred from the treated water tank 6 to the first chamber 2 of the anaerobic filter bed tank). The amount of water corresponding to the amount of water is also transferred to the treated water tank 6 through the advection port 17 provided in the lower part of the partition wall 1G of the biological filtration unit 5 and the treated water tank 6.

The treated water transferred to the treated water tank 6 is temporarily stored in the treated water tank 6 and finally transferred to the disinfection tank 7. A part of the stored treated water is transferred to the first chamber 2 of the anaerobic filter bed tank by the air lift pump 18A. In this embodiment, the air lift pump 18A has an upper part 21b so that the first air pipe 20A for pumping the circulating water is installed in the vertical pumping part 21a of the pumping pipe 21 as shown in FIG. The second air pipe 22A for pumping cleaning waste water is connected from the side of the vertical pumping section 21a.
In normal operation, air is supplied to the first air pipe 20A and air is not supplied to the second air pipe 22A, and the treated water is circulated in the first anaerobic filter bed chamber 1 of the transfer destination. Water is transferred so that the amount of inflow water (daily average amount of sewage) is about three times as much.
The treated water transferred to the disinfecting tank 7 is disinfected by coming into contact with the chlorinated solid disinfectant housed in the medicine cylinder, and flows out of the waste water purification tank 1 from the outlet 23.

  On the other hand, if the normal operation is continued, the particulate carrier of the filter bed 16 of the biological filtration unit 5 is clogged by the trapped suspended matter and the grown biofilm, so that it is necessary to periodically clean the filter bed 16. The filter bed 16 is washed by being supplied from an air diffuser (aeration cleaning device) 15 installed at the bottom of the biological filtration unit 5, and settles on the carrier outflow suppression plate 29 below the filter bed 16. The granular carrier becomes a fluid state between the upper and lower carrier outflow prevention plates 28 and 29, and the trapped suspended matter and the biofilm are separated from the carrier and flow. Simultaneously with the air supply to the air diffuser 15, the air is also supplied to the second air pipe 22 </ b> A connected to the air lift pump 18 </ b> A, so that the water pump installed near the advection port 17 with the biological filtration unit 5. Washing wastewater containing suspended solids separated from the suction port 19 is transferred to the first chamber 2 of the anaerobic filter bed tank.

<Example>
The effect of the present invention was confirmed using the air lift pump 18A described as the first embodiment based on FIG.
The air lift pump 18A used in this example is a PVC pipe (VP30) having a pipe diameter D (inner diameter) of 30 mm as the pumping pipe 21, and pipe diameters d ₁ and d ₂ (inner diameter) as the first air pipe 20A and the second air pipe 22A. ) A 13 mm PVC pipe (VP13) was used. These are assembled, and with respect to the water surface of the treated water tank 6 (water level 1240 mm from the bottom wall 1B of the sewage purification tank 1), the immersion depth of the pumping pipe 21 is 1190 mm, the lifting height is 160 mm, and the immersion depth h of the first air pipe 20A ₁ is 1100 mm, (so the connection between the riser pipe 21 at right angles, the display at the center of the second air pipe 22A) immersion depth _{h 2} of the second air pipe 22A is 1150mm was.
The first air pipe 20A is provided with an orifice 41a having a diameter of 1.4 mm as the air supply amount adjusting mechanism 41. The second air pipe 22A is provided with an orifice 42a having a diameter of 2.3 mm as an air supply amount adjusting mechanism 42.

In this air lift pump 18A, by supplying air from the air supply device 40 to the pumping pipe 21 through the first air pipe 20A as a route, it was possible to transfer 2.4 L / min of circulating water. Furthermore, by supplying air from the air supply device 40 to the pumping pipe 21 through the second air pipe 22A as a path, 11.5 L / min of washing waste water could be transferred.
Thus, according to the present invention, it was confirmed that one air lift pump 18A can transfer the transfer water having an appropriate amount of water as circulating water or washing waste water.
In addition, since the water level of the aerobic treatment tank 31 and the treated water tank 6 falls along with progress of operation time and the amount of transferred water also declines in connection with this, the washing waste_water | drain was shown with the water quantity immediately after a washing | cleaning start.

  In addition, the sewage septic tank 1 (five-person tank) equipped with this air lift pump 18A is installed in a detached house (five actual use personnel), and the circulating water is always transferred, and the cleaning wastewater is transferred three times a day. As a result, the amount of circulating water and the amount of washing wastewater change within the specified setting range for 4 months, which is the maintenance inspection interval defined by the Septic Tank Law, and exhibit a stable transfer function. I was able to.

DESCRIPTION OF SYMBOLS 1 ... Waste water purification tank, 1A ... Perimeter wall, 1B ... Bottom wall, 1C ... Ceiling wall, 1D, 1E, 1F, 1G, 1H ... Partition wall, 2 ... Anaerobic filter bed tank 1st chamber, 2a, 3a ... Scum storage part, 2b, 2b ... sludge storage part, 3 ... anaerobic filter bed 2nd chamber, 4 ... contact aeration part, 5 ... biological filtration part, 6 ... treated water tank, 7 ... disinfection tank, 8, 9, 16, 27 ... filtration Floor, 8A, 9A ... Filter medium outflow prevention plate, 8B, 9B ... Bulkhead, 10 ... Flow rate adjusting device, 11 ... Flow rate adjusting unit, 12, 13, 17 ... Advection port, 14 ... Air diffuser, 15 ... Air diffuser (aeration Cleaning device), 18A, 18B, 18C, 18D, 18E ... air lift pump, 19 ... suction port, 20A, 20B, 20C, 20D, 20E ... first air piping, 22A, 22B, 22C, 22D, 22E ... second air Piping, 20a, 22a, 32a ... opening, 21 ... pump, 21a ... lead Pumping section, 21b ... upper part, 21c ... horizontal introduction section, 23 ... outlet, 24 ... inlet, 25, 26 ... advection section, 28, 29 ... carrier outflow suppression plate, 30 ... anaerobic treatment tank, 31 ... aerobic treatment Tank, 32D, 32E ... Junction piping, 33D, 33E ... Junction point, 40 ... Air supply device, 40a ... Switching valve, 40b ... Switching valve control unit, 41, 42 ... Air supply amount adjustment mechanism, 41a, 42a ... Orifice, 41b, 42b ... air control valve, 43 ... first air supply apparatus, 44 ... second air supply device, 45 ... air supply device controller, 50, 51 ... air supply, D ... tube _diameter, d 1, _{d 2} , D ₃ ... tube diameter, h ₁ , h ₂ , h ₃ ... immersion depth

Claims (7)

A sewage septic tank having a front treatment tank and an aerobic treatment tank disposed in the subsequent stage,
An aerobic cleaning device for cleaning the filter bed of the aerobic treatment tank by aeration;
Washing wastewater that is disposed in the aerobic treatment tank or in the subsequent stage and is transferred to the preceding treatment tank as a part of the treated water that has been treated in the aerobic treatment tank and is washed by the aeration washing apparatus. An air lift pump for transferring the water to the pre-treatment tank,
The air lift pump serves as a transfer path for the circulating water and washing waste water;
A first air pipe connected to the pumping pipe for supplying air necessary for pumping the circulating water;
A sewage septic tank, comprising: a second air pipe connected to the pumping pipe for supplying air necessary for pumping the washing waste water.   The sewage septic tank according to claim 1, further comprising an orifice or an air adjustment valve for adjusting an amount of air supplied into the path of the first air pipe.   The sewage septic tank according to claim 1 or 2, further comprising an orifice or an air adjustment valve for adjusting an amount of air supplied into a path of the second air pipe.   The sewage septic tank according to any one of claims 1 to 3, wherein the opening of the second air pipe is formed at a position deeper than the opening of the first air pipe.   The sewage septic tank according to any one of claims 1 to 4, wherein a pipe diameter of the second air pipe is formed larger than a pipe diameter of the first air pipe.   The sewage septic tank according to any one of claims 1 to 5, wherein the front-stage treatment tank is an anaerobic treatment tank. It is a method for operating a sewage septic tank having a pretreatment tank and an aerobic treatment tank arranged in the subsequent stage,
The sewage septic tank is
An aerobic cleaning device for cleaning the filter bed of the aerobic treatment tank by aeration;
Washing wastewater that is disposed in the aerobic treatment tank or in the subsequent stage and is transferred to the preceding treatment tank as a part of the treated water that has been treated in the aerobic treatment tank and is washed by the aeration washing apparatus. An air lift pump for transferring the water to the pre-treatment tank,
The air lift pump serves as a transfer path for the circulating water and washing waste water;
A first air pipe and a second air pipe connected to the pumping pipe;
Pumping the circulating water by supplying air to the first air pipe;
A method for operating a sewage septic tank, wherein the cleaning waste water is pumped up by supplying air to the aeration apparatus and supplying air to a second air pipe.

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