JP4002115B2 - Septic tank - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a septic tank that purifies sewage such as human waste and household wastewater.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a septic tank that purifies sewage discharged from households and the like such as human waste and household wastewater is known. Among these septic tanks, a so-called merger processing septic tank has, for example, a shell structure, and includes four chambers: an anaerobic filter bed first chamber, an anaerobic filter bed second chamber, a contact aeration tank, and a sedimentation tank. (Hereinafter, these are also referred to as “purification chambers”). These four purification chambers are each formed by being partitioned by a partition plate disposed inside the purification tank. Water is stored in each of these purification chambers, and the sewage is gradually purified by circulating through each chamber.
[0003]
In such a septic tank, strength is imparted to the partition plate in order to prevent deformation of the partition plate based on the water pressure of the water stored in each septic chamber. For example, Japanese Patent Application Laid-Open No. 2001-97481 discloses a septic tank that uses a partition plate having reinforcing ribs in which three ribs are connected by linear ribs.
[0004]
[Problems to be solved by the invention]
By the way, after the septic tank is installed at a predetermined place, maintenance is performed after a certain period of time, and when the maintenance is performed, water stored in each septic chamber is temporarily discharged by an underwater pump. Here, when water is discharged from only one chamber, there is a concern that the partition plate is deformed due to the water pressure of the adjacent chamber. In particular, when only the water in the second anaerobic filter bed chamber 2 was discharged, the water pressure in the adjacent anaerobic filter bed first chamber and the contact aeration tank was subject to great concern.
[0005]
However, in the septic tank disclosed in the above publication, the water pressure applied to the partition plate is supported only by the rigidity of the partition plate having a predetermined rib structure. For this reason, there is a problem that the partition plate needs a certain thickness and has an excessive rib structure, but its reliability is low.
[0006]
Therefore, the object of the present invention is to increase the strength of the partition plate without using an excessive rib structure even if the plate thickness of the partition plate in the septic tank is reduced, and to prevent the partition plate from being deformed by water pressure, especially during maintenance. Is to be able to.
[0007]
[Means for Solving the Problems]
In the present invention that has solved the above problems, a plurality of partition plates are disposed inside a hollow septic tank body, and the interior of the septic tank body is partitioned by the plurality of partition plates to form a purification chamber. In the septic tank in which the upper mesh member and the lower mesh member sandwiching the purification material from above and below are disposed, ribs are formed on each of the facing surfaces of the adjacent partition plates among the plurality of partition plates, An upper reinforcing member made of a long material having a L-shaped or U-shaped cross section made of fiber reinforced plastic is disposed above the upper mesh material between the partition plates to be operated, and below the lower mesh material between the adjacent partition plates. the lower reinforcing member in which the fiber-reinforced plastic cross section formed of an elongated member which is L-shaped or U-shaped is provided, end portions of the upper reinforcement member and the rib, and the lower reinforcing member and Li DOO are fixed respectively, the reinforcing member may be to impart strength to the adjacent partition plates.
Moreover, the long material can also be made into the aspect manufactured by pultrusion molding.
[0008]
As described above, in the present invention, a reinforcing member made of a long material having an L-shaped cross section made of fiber reinforced plastic is disposed between adjacent partition plates, and gives strength to each partition plate. ing. For this reason, it is possible to effectively prevent the adjacent partition plates from being deformed. For example, even when the purification chamber sandwiched between these partition plates receives water pressure from the adjacent purification chamber during maintenance, the partition plates Deformation can be prevented.
[0009]
The “L-shaped cross section” in the present invention is a member having a bottom plate and a side plate, and the bottom plate and the side plate are in a bent state. Accordingly, the bottom plate and the side plate are not in a right angle relationship, and the bent portion is not limited to a sharp one, and may be chamfered, for example.
[0010]
Further, in the septic tank in which a plurality of partition plates are arranged inside the hollow septic tank body, and a plurality of septic chambers are formed by partitioning the inside of the septic tank body by the plurality of partition plates, among the plurality of partition plates. A rib is formed on each of the opposing surfaces of the partition plate, and a reinforcing member made of a long material having a U-shaped cross section manufactured by fiber reinforced plastic is disposed between the adjacent partition plates, and an end portion of the reinforcing member The ribs are fixed, and the reinforcing member imparts strength to each of the adjacent partition plates.
[0011]
When a U-shaped reinforcing member is used as the reinforcing member, it is possible to give the partition plate greater strength than the L-shaped reinforcing member. For this reason, a deformation | transformation of a partition plate can be prevented further suitably.
[0012]
Here, the “cross-sectional U-shape” referred to in the present invention means a plate having a bottom plate and side plates erected along both side edges. Therefore, the bottom plate and the side plate do not have to be in a right angle relationship, and the bent portion is not limited to a sharp one, and may be chamfered, for example.
[0013]
In addition, a plurality of partition plates are disposed inside the hollow septic tank body, the inside of the septic tank body is partitioned by the plurality of partition plates to form a purification chamber, and a purification material is disposed in the purification chamber. In the septic tank in which the upper mesh material and the lower mesh material sandwiching the purification material from above and below are arranged, ribs are formed on each of the facing surfaces of the adjacent partition plates among the plurality of partition plates, and the upper mesh material between the adjacent partition plates An upper reinforcing member made of a long material having an L-shaped cross section manufactured by fiber reinforced plastic is disposed above, and a U-shaped cross section manufactured by fiber reinforced plastic below the lower mesh material between adjacent partition plates. A lower reinforcing member made of a long material having a shape is disposed, and an end portion and a rib of the upper reinforcing member, and an end portion and a rib of the lower reinforcing member are respectively fixed, and the reinforcing member , Characterized in that impart strength to the adjacent partition plates.
[0014]
In the present invention, a U-shaped reinforcing member that provides a relatively large strength is disposed at a lower position, and an L-shaped reinforcing member that provides a lower strength than the U-shaped reinforcing member is disposed. It is installed. In the septic tank, since a high water pressure is applied below, it is preferable to give high strength to the lower position. In this regard, in the present invention, since the U-shaped reinforcing member that imparts high strength is disposed, deformation of the partition plate can be more suitably prevented.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In addition, the same code | symbol shall be used for the same element and the overlapping description is abbreviate | omitted.
[0016]
FIG. 1 is a partially broken perspective view showing the inside of a septic tank according to the present invention, and FIG. 2 is a front sectional view of the septic tank according to the present invention.
[0017]
As shown in FIGS. 1 and 2, the septic tank 1 according to the present embodiment is a so-called merged septic tank and has a shell structure including a hollow septic tank body 2. The top plate portion 2A of the septic tank body 2 is provided with a plurality of, in the present embodiment, four inspection ports 3, 3,. The maintenance of the septic tank 1 is performed by opening the inspection ports 3, 3. In addition, an inlet 4 through which human waste or household wastewater flows in is formed on one side 2B of the septic tank body 2, and an outlet 5 through which purified purified water is discharged is formed on the other side 2C. ing.
[0018]
Inside the septic tank body 2, a plurality of, in this embodiment, three partition plates 6, 7, 8 are arranged so as to extend in the vertical direction. Among these, the 1st partition plate 6 is arrange | positioned in the position nearest to the one side 2B of the septic tank main body 2, and between the one side 2B of the septic tank main body 2 and the 1st partition plate 6, the anaerobic filter bed tank 1st is shown. One chamber 11 is formed. A second partition plate 7 is disposed at a position closer to the other side 2C side of the septic tank body 2 than the first partition plate 6, and anaerobic is provided between the first partition plate 6 and the second partition plate 7. A filter bed tank second chamber 12 is formed. A third partition plate 8 is disposed on the other side 2C side of the septic tank body 2 further than the second partition plate 7, and a contact aeration tank is provided between the second partition plate 7 and the third partition plate 8. 13 is formed. Furthermore, a settling tank 14 is formed between the third partition plate 8 and the other side 2C of the septic tank body 2, and a disinfection tank 15 is provided above the settling tank 14.
[0019]
In addition, a flow channel 6A that communicates in the vertical direction is formed on the first partition plate 6 on the first chamber 11 side of the anaerobic filter bed tank, and the flow channel 6A communicates with an upper center portion of the first partition plate 6. A communicating hole 6B is formed. The sewage purified in the anaerobic filter bed tank first chamber 11 flows into the anaerobic filter bed tank second chamber 12 through the flow channel 6A and the communication hole 6B. The second partition plate 7 has an anaerobic filter tank second chamber 12 side formed with a flowing water channel 7A that communicates with the vertical direction, and the upper central portion of the second partition plate 7 communicates with the flowing water channel 7A. A hole 7B is formed. The sewage purified in the second chamber of the anaerobic filter bed tank flows into the contact aeration tank 13 through the flow channel 7A and the communication hole 7B. A narrow water channel 8 </ b> A is formed in the lower center portion of the third partition plate 8. The sewage purified in the contact aeration tank 13 flows into the settling tank 14 through the flowing water channel 8A.
[0020]
In the anaerobic filter bed first chamber 11, a large number of filter media 21, 21. A large number of anaerobic bacteria (not shown) adhere to the filter media 21, 21, and the organic matter in the sewage is decomposed to purify the sewage. These filter media 21, 21... Are placed on the lower net 22, and the upper net 23 is placed on the filter media 21, 21. The mesh of these upper and lower nets 22, 23 is set smaller than the diameter of the filter media 21, 21. For this reason, the filter media 21, 21,... In this way, the filter media 21, 21... Are sandwiched from above and below by the lower net 22 and the upper net 23, so that the filter media 21, 21.
[0021]
In the anaerobic filter bed second chamber 12, a large number of filter media 24, 24. A large number of anaerobic bacteria (not shown) adhere to the filter media 24, 24..., And further decompose organic substances in the sewage flowing from the anaerobic filter bed first chamber 11 to purify the sewage. The filter media 24, 24... Are placed on a lower net 25 that is a lower mesh material, and the upper net 26 that is an upper mesh material is placed on the filter media 24, 24. The mesh of these upper and lower nets 25, 26 is set smaller than the diameter of the filter media 24, 24. Therefore, the filter media 24, 24... Do not come out from between the upper and lower nets 25, 26. Thus, the filter media 24, 24... Are sandwiched from above and below by the lower net 25 and the upper net 26 so that the filter media 24, 24... Are accommodated in the second chamber 12 of the anaerobic filter bed tank. Further, lower reinforcing members 31 and 32 (FIG. 3) are disposed below the lower net 25, and upper reinforcing members 33 and 34 are disposed above the upper net 26. Details of this will be described later.
[0022]
A large number of contact materials 27, 27... Are arranged in the contact aeration tank 13. A large number of aerobic bacteria (not shown) are in contact with the contact material 27, and organic substances in the sewage flowing from the second chamber 12 of the anaerobic filter bed are further decomposed to purify the sewage. In addition, air is sent to the contact aeration tank 13 by a blower (blower) (not shown), and by supplying sufficient air (oxygen) to the water in the contact aeration tank 13, the activity of aerobic bacteria is promoted and purified. Is promoting. These many contact materials 27, 27... Are placed on the lower net 28, and the upper net 29 is placed on the contact materials 27, 27. The contact members 27, 27... Are sandwiched from above and below by the lower net 28 and the upper net 29 so that the contact members 27, 27.
[0023]
In the sedimentation tank 14, the sewage purified in the first chamber, the second chambers 11 and 12, and the contact aeration tank 13 flows in, and sludge contained in the sewage is precipitated. The supernatant water flows into the disinfection tank 15. The disinfection tank 15 is connected to the discharge port 5, and after disinfecting the supernatant water flowing in from the settling tank 14 as appropriate, it is discharged from the discharge port 5 to a river or the like.
[0024]
In addition, in the second chamber 12 of the anaerobic filter bed tank of the septic tank 1 according to the present embodiment, as shown in FIGS. 3 and 4, two lower reinforcing members 31, 32 and two upper reinforcing members 33, 34 are provided. Is arranged. Of these, the lower reinforcing member 31 is made of a long material having a U-shaped cross section made of fiber reinforced plastics (hereinafter referred to as “FRP”), and includes a bottom plate 31A and side plates 31B and 31C. The lower reinforcing member 31 is manufactured as a glass fiber reinforced plastic by pultrusion molding which has a high glass content and is effective in strength. The other lower reinforcing member 32 is manufactured in the same manner. Lower reinforcing members 31 and 32 has its longitudinal direction arranged to extend in the detaching direction of the first partition plate 6 and the second partition plate 7, the lower portion of the first partition plate 6 and the second partition plate 7 Deformation is prevented.
[0025]
The upper reinforcing member 33 is made of a long material having an L-shaped cross section manufactured by FRP, and includes a bottom plate 33A and side plates 33B. Similar to the lower reinforcing member 31, the upper reinforcing member 33 is also manufactured by pultrusion which has a high glass content and is effective in strength. The other upper reinforcing member 34 is also manufactured in the same manner as the upper reinforcing member 33. Upper reinforcing member 33 has its longitudinal direction arranged to extend in the detaching direction of the first partition plate 6 and the second partition plate 7, the upper portion of the first partition plate 6 and the second partition plate 7 Deformation is prevented.
[0026]
Furthermore, four ribs 6D to 6G and ribs 7D to 7G are disposed on the opposing surfaces 6C and 7C of the adjacent first partition plate 6 and second partition plate 7, respectively. The four ribs 6D to 6G formed on the surface 6C of the first partition plate 6 are long materials having a rectangular cross section extending in the depth direction, and all have the same shape. These ribs 6D to 6G are spaced apart in the vertical direction. On the other hand, each of the four ribs 7D to 7G formed on the surface 7C of the second partition plate 7 is a long material having a rectangular cross section extending in the depth direction, and all have the same shape. These ribs 7D to 7G are arranged at the same height positions as 6D to 6G arranged on the surface 6C of the first partition plate 6, respectively.
[0027]
Both end portions of the bottom plates 31A and 32A in the lower reinforcing members 31 and 32 are fixed to the upper surfaces of the ribs 6D and 7D arranged at the same height position by rivets R and R, respectively. At this time, the lower reinforcing members 31 and 32 are disposed so that the side plates 31B, 31C, 32B, and 32C extend upward. Further, both end portions of the bottom plates 33A and 34A in the upper reinforcing members 33 and 34 are fixed to the upper surfaces of the ribs 6F and 7F arranged at the same height position by rivets R and R, respectively. At this time, the upper reinforcing members 33 and 34 are disposed so that the side plates 33B and 34B extend upward. The lower reinforcing members 31 and 32 and the upper reinforcing members 33 and 34 arranged in this way are all in a horizontal state. Further, the lower net 25 is placed on the lower reinforcing members 31 and 32, and the upper net 26 is arranged below the upper reinforcing members 33 and 34. The lower net 25 is supported by the lower reinforcing members 31 and 32, and the upper net 26 is prevented from being lifted by the upper reinforcing members 33 and 34.
[0028]
Next, the manufacturing procedure of the anaerobic filter bed second chamber 12 which is a characteristic part of the present embodiment in the septic tank 1 having the above structure will be described.
[0029]
First, as shown in FIG. 5, the ribs 6 </ b> D to 6 </ b> G are disposed on the surface 6 </ b> C of the first partition plate 6 in the septic tank body 2, and the ribs 7 </ b> D to 7 </ b> G are disposed on the surface 7 </ b> C of the second partition plate 7. Next, when these ribs 6D to 6G and 7D to 7G are arranged, the lower reinforcing members 31 and 32 are installed between the ribs 6D and 7D. The lower reinforcing members 31 and 32 are arranged such that both end portions of the bottom plates 31A and 32A are placed on the ribs 6D and 7D, respectively. Subsequently, as shown in FIG. 6, one end portion of the bottom plate 32 </ b> A of the lower reinforcing member 32 is fixed to the rib 6 </ b> D by the rivet R. Here, since the bottom reinforcing member 32 is fixed to the rib 6D by the rivet R is the plate-like bottom plate 32A, the lower reinforcing member 32 can be easily fixed to the rib 6D. Similarly, the other end of the bottom plate 32A of the lower reinforcing member 31 is fixed to the rib 7D with a rivet. Also, one end of the bottom plate 32A of the lower reinforcing member 32 is fixed to the rib 6D and the other end is fixed to the rib 7D by rivets. Thus, the lower reinforcing members 31 and 32 are fixed to the ribs 6D and 7D.
[0030]
When the lower reinforcing members 31 and 32 are fixed to the ribs 6D and 7D, the lower net 25 is placed on the lower reinforcing members 31 and 32 as shown in FIG. At this time, although the lower net 25 has a certain degree of strength, it is merely placed on the lower reinforcing members 31 and 32, so that the strength between the first partition plate 6 and the second partition plate 7 is reinforced. It does not play a role.
[0031]
When the lower net 25 is placed on the lower reinforcing members 31, 32, as shown in FIG. 8, a large number of filter media 24, 24... Are placed, and the upper net 26 is placed on these filter media 24, 24. Place. Here, the number of filter media 24, 24... To be placed on the lower net 25 can be adjusted so that the upper net 26 is substantially at the same height as the ribs 6 F and 7 F in the partition plates 6 and 7. . The upper net 26 prevents the filter media 24, 24... From being lifted, and the filter media 24, 24.
[0032]
When the upper net 26 is placed on the filter media 24, 24..., The upper reinforcing members 33 and 34 are installed between the ribs 6F and 7F. The upper reinforcing members 33 and 34 are arranged in such a manner that both end portions of the bottom plates 33A and 34A are placed on the ribs 6F and 7F, respectively. Subsequently, as shown in FIG. 9 representing a portion surrounded by an imaginary line in FIG. 8, one end of the upper reinforcing member 33 is fixed to the rib 7 </ b> F by a rivet R. Here, since the upper reinforcing member 33 is fixed to the rib 7F by the rivet R is a plate-like bottom plate 33A, the upper reinforcing member 33 can be easily fixed to the rib 7F. Similarly, the other end of the bottom plate 33A of the upper reinforcing member 33 is fixed to the rib 6F with a rivet. Further, one end of the bottom plate 34A of the upper reinforcing member 34 is fixed to the rib 7F and the other end is fixed to the rib 6F by rivets. Thus, the upper reinforcing members 33 and 34 are fixed to the ribs 6F and 7F.
[0033]
By fixing the upper reinforcing members 33 and 34 to the ribs 6F and 7F, the upper reinforcing members 33 and 34 are disposed above the upper net 26. For this reason, it can support from the upper part of the upper net 26, and can prevent the floating. Therefore, it is possible to prevent the upper net 26 from floating and the upper net 26 from floating or the filter media 24, 24.
[0034]
Thus, in the anaerobic filter bed second chamber 12 in the manufactured septic tank 1, the reinforcing members 31 to 34 are disposed between the first partition plate 6 and the second partition plate 7, and the first partition plate 6. Further, the second partition plate 7 is given strength. For this reason, even if the plate thickness of the 1st partition plate 6 and the 2nd partition plate 7 is made thin, it can be set as sufficient intensity | strength. Therefore, for example, during the maintenance of the septic tank 1, only the water in the anaerobic filter bed tank second chamber 12 is discharged, and the side of the anaerobic filter bed tank second chamber 12 is within the side of the anaerobic filter bed tank second chamber 12. The first partition plate 6 and the second partition plate 7 can be prevented from being deformed even when the water pressure in the contact aeration tank 13 is applied. Thus, since the thickness of the partition plates 6 and 7 can be reduced, the weight of the partition plates 6 and 7 can be reduced, so that it is easy to carry in and attach the partition plates 6 and 7. became.
[0035]
Further, since the upper reinforcing members 33 and 34 are disposed above the upper net 26, the upper reinforcing members 33 and 34 provide strength to the first partition plate 6 and the second partition plate 7 and support to prevent the upper net 26 from being lifted up. It is also used as a material. For this reason, it is not necessary to separately provide a support member for preventing lifting in addition to the reinforcing member, which can contribute to a reduction in the number of parts. Further, the upper reinforcing members 33 and 34 are L-shaped in cross section, and the lower reinforcing members 31 and 32 are U-shaped in cross section having a strength higher than that of the L-shaped cross section. For this reason, since high intensity | strength can be provided with respect to the downward position with a large water pressure, the deformation | transformation of the 1st partition plate 6 and the 2nd partition plate 7 can be prevented suitably.
[0036]
Here, the present inventors conducted an experiment for confirming the effect of the present invention. The experiment was performed using a septic tank having a width of 3600 mm, a depth of 1600 mm, and a height of 2000 mm. Here, when the reinforcing member in the present invention is not provided and the reinforcing plate in the present invention is provided when a 6.5 mm partition plate is used, the same strength can be obtained even if the partition plate is 4.5 mm. I was able to. For this reason, it turned out that the board thickness of a partition plate can be made thin.
[0037]
The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment. For example, in the said embodiment, in order to make the process of the reinforcement members 31-34 easy, it has arrange | positioned so that the side plates 31B, 31C, 32B, 32C of the lower reinforcement members 31 and 32 may extend upwards. On the other hand, as shown to Fig.10 (a), it can also arrange | position so that the side plates 31B and 31C of the lower reinforcement member 31 may extend upwards. In this case, it is preferable to cut part of the side plates 31B and 31C of the lower reinforcing member 31 to form the notch 31E. The lower reinforcing member 31 can be fixed to the rib 7D easily and reliably by fitting the notch 31E to the rib 6E. Similarly, the side plates 33B and 34B of the upper reinforcing members 33 and 34 are arranged so as to extend upward. On the other hand, as shown in FIG.10 (b), it can also arrange | position so that the side plates 33B and 33C of the upper reinforcement member 33 may extend upwards. In this case, it is preferable to cut part of the side plates 33B and 33C of the upper reinforcing member 33 to form the notch 33E. The upper reinforcing member 33 can be easily and reliably fixed to the rib 7F by arranging the notch 33E so as to fit into the rib 6F.
[0038]
Moreover, in the said embodiment, the lower reinforcement members 31 and 32 and rib 6D, 7D were fixed with the rivet R so that attachment might become easy, and the upper reinforcement member 33, 34 was fixed to rib 6F, 7F. On the other hand, it can also be set as the aspect which fixes these by screwing, for example with screwing members, such as a screw and a volt | bolt.
[0039]
On the other hand, in the above embodiment, in order to give higher strength to the lower position of the septic tank, a U-shaped reinforcing member is disposed below, and an L-shaped reinforcing member is disposed above. On the other hand, a reinforcing member having a U-shaped cross section or an reinforcing member having an L-shaped cross section may be used for both the upper and lower sides.
[0040]
【The invention's effect】
As described above, according to the present invention, even if the thickness of the partition plate in the septic tank is reduced, the strength of the partition plate is increased without using an excessive rib structure. It is possible to prevent deformation.
[Brief description of the drawings]
FIG. 1 is a partially broken perspective view showing the inside of a septic tank according to the present invention.
FIG. 2 is a front sectional view of a septic tank according to the present invention.
FIG. 3 is a cutaway perspective view showing the inside of the septic tank body.
FIG. 4 is an enlarged perspective view of a joint between a rib and a reinforcing member.
FIG. 5 is a diagram for explaining a manufacturing procedure of the second chamber of the anaerobic filter bed.
6 is a diagram showing a step following FIG. 5. FIG.
7 is a diagram showing a step that follows the step of FIG. 6. FIG.
FIG. 8 shows a step shown in FIG. 7;
FIG. 9 is an enlarged perspective view of a joint portion between an upper reinforcing member and a rib.
FIGS. 10A and 10B are enlarged perspective views showing a modified example of a joint portion between a rib and a reinforcing member.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Septic tank, 2 ... Septic tank main body, 2A ... Top plate part, 2B ... One side, 2C ... Other side, 3 Inspection port, 4 ... Inlet, 5 ... Outlet, 6-8 ... Partition plate 6, D-6F , 7D-7F ... ribs, 11 ... anaerobic filter bed first chamber, 12 ... anaerobic filter bed second chamber, 13 ... contact aeration tank, 14 sedimentation tank, 15 ... disinfection tank, 21, 24 ... filter medium, 22, 25 ... Lower net, 23, 26 ... upper net material, 27 ... contact material, 31, 32 ... lower reinforcing member, 31A, 32A ... bottom plate, 31B, 31C, 32B, 32C ... side plate, 33, 34 ... upper reinforcing member, 33A, 34A ... bottom plate, 33B, 33C, 34B, 34C ... side plate.

Claims (2)

A plurality of partition plates are disposed inside the hollow septic tank body, the inside of the septic tank body is partitioned by the plurality of partition plates to form a purification chamber, and a purification material is disposed in the purification chamber, In the septic tank in which the upper netting material and the lower netting material sandwiching the purifying material from above and below are arranged,
Among the plurality of partition plates, a rib is formed on each of the facing surfaces of the adjacent partition plates,
Above the upper mesh material between the adjacent partition plates , an upper reinforcing member made of a long material having a cross-sectional shape made of fiber reinforced plastic having an L shape or a U shape is disposed,
Below the lower mesh material between the adjacent partition plates , a lower reinforcing member made of a long material whose cross-sectional shape made of fiber reinforced plastic is L-shaped or U-shaped ,
The end of the upper reinforcing member and the rib, and the end of the lower reinforcing member and the rib are fixed, respectively.
The septic tank, wherein the reinforcing member imparts strength to the adjacent partition plate.   The septic tank according to claim 1, wherein the long material is manufactured by pultrusion molding.

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