JP2005199277A - Septic tank - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a septic tank in which a discharging pipe bottom can be made shallow and thereby construction work becomes easy. <P>SOLUTION: In the septic tank, an internal part is divided into two or more chambers, a solid-liquid separator 11 in which almost all solid matters in water to be treated are separated and are dropped to a lower part of a sludge storage tank 1 being a first chamber is provided at an upper part of the sludge storage tank 1 and the water to be treated flows in the solid-liquid separator 11 from an inflow pipe 6 for making the water to be treated flow in the septic tank. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a septic tank for treating sewage.

  Examples of conventional septic tanks include those listed in Non-Patent Document 1 below. As shown in FIG. 8, the septic tank shown in Non-Patent Document 1 includes an anaerobic filter bed first chamber 101, an anaerobic filter bed second chamber 102, a biological filtration tank 103, a treated water tank 104, and a disinfection tank 105. It has. The anaerobic filter bed first chamber 101 and the anaerobic filter bed second chamber 102 are a primary treatment tank S10 that performs a primary treatment of sewage (treated water) that flows in from the inflow pipe 106, and the biological filtration tank 103 and The treated water tank 104 is a secondary treatment tank S20 that performs a secondary treatment of the treated water subjected to the primary treatment. The biological filtration tank 103 has a two-layer structure in which the upper part is a carrier flow tank 103a and the lower part is a biological filtration tank 103b. The blower 110 constantly supplies air to the carrier flow tank 103a, and the blower 111 supplies air to the biological filtration tank 103b for backwashing once a day.

  A substantially constant amount of treated water is transferred from the anaerobic filter tank first chamber 101 to the anaerobic filter bed second chamber 102 by a flow rate adjusting device 108 using an air lift pump regardless of fluctuations in the amount of inflow of sewage. Is done. As described above, in the septic tank, the flow rate is generally adjusted by the pump in order to stabilize the water quality. Further, the water to be treated is transferred from the second chamber 102 of the anaerobic filter tank to the biological filtration tank 103 through the advection port 112. Accordingly, during normal operation, the water levels in the second chamber 102 and the biological filtration tank 103 are the same.

The treated water subjected to the secondary treatment is transferred from the treated water tank 104 to the sterilization tank 105, sterilized, and discharged from the discharge pipe 107. In addition, a part of the treated water in the treated water tank 104 is always returned to the first anaerobic filter bed tank 101 by the circulating water transfer pipe 109, and again, the anaerobic filter bed tank second chamber 102, the biological filter tank. It flows into the treated water tank 104 through 103. Thus, in general, in the septic tank, the water to be treated is constantly circulated. By this circulation, denitrification of the water to be treated occurs, the burden on the biological filtration tank 103 is reduced, and the water quality is improved. .
Japan Environmental Maintenance Education Center, “Advanced treatment type (nitrogen removal type, small capacity type, membrane separation type) small merged treatment septic tank maintenance management workshop text”, 1st edition, Japan Environmental Education Center, Heisei February 2013, p. 142-175

  An object of the present invention is to provide a septic tank that can be easily constructed because the bottom of the discharge pipe can be shallow.

  The septic tank of the present invention is a septic tank whose interior is partitioned into a plurality of chambers, and substantially separates solids in the water to be treated at the top of the first chamber (hereinafter referred to as the first chamber) counted from the upstream side. A solid-liquid separation device for dropping to the lower part of the first chamber and configured to allow the water to be treated to flow into the solid-liquid separation device from an inflow pipe through which the water to be treated flows into the septic tank. Features.

  Here, a primary treatment tank in which the first chamber is provided to primarily treat the treated water, a secondary treatment tank for secondary treatment of the treated water subjected to the primary treatment, and the primary treatment tank A pumping means for pumping water to be treated into the secondary treatment tank, and the secondary treatment tank is preferably set to a higher water level than the primary treatment tank by the pumping means during normal operation. .

  If it does in this way, since the water level of a secondary processing tank can be made high, the position of a discharge pipe bottom will become shallow, it will become easy to attach the gradient when connecting a discharge pipe to a side ditch, etc., and construction will become easy.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  As shown in FIGS. 1 and 2, the septic tank of this embodiment includes a tank T having three openings H1, H2, and H3 that serve as inspection ports on the upper surface, and a lid L1 that opens and closes the openings H1, H2, and H3. , L2 and L3, and the inside of the tank T is partitioned by the partition walls 10, 20, and 30, so that the sludge storage tank 1 as the first chamber, the preliminary filtration tank 2 as the second chamber, the third A carrier flow tank 3 as a chamber and a biological filtration tank 4 as a fourth chamber are formed. The sludge storage tank 1 and the preliminary filtration tank 2 are primary treatment tanks S1 that perform primary treatment (anaerobic treatment in this embodiment) of the water to be treated, and the carrier fluidization tank 3 and the biological filtration tank 4 are 2 of the water to be treated. The secondary processing tank S2 performs the next processing (aerobic processing in the present embodiment). In addition, a disinfection tank 5 is disposed above the biological filtration tank 4 inside the tank T.

  The sludge storage tank 1 includes a solid-liquid separation unit (also referred to as a solid-liquid separation device) 11 disposed in the upper part and a sludge concentration storage part 12 disposed in the lower part. The solid-liquid separation device 11 is a device that roughly separates impurities (solid matter) and liquid in sewage. The solid-liquid separator 11 is disposed below the opening H1 that is an inspection port. In the solid-liquid separator 11, the outlet 61 of the inflow pipe 6 through which sewage flows is arranged at the upper part of the central front part 15, and the outlet 81 of the backwash drainage return pipe 8 is arranged at the upper part of the central rear part 16. .

  As shown in FIG. 3, the solid-liquid separator 11 is a substantially box body surrounded by a front wall portion 11 a, a rear wall portion 11 b, a right wall portion 11 c, and a left wall portion 11 d and opened upward and downward. This is fixed to the partition wall 10. In addition, let the front and rear, right and left in the septic tank and the solid-liquid separator 11 of this embodiment be the directions shown by the arrows in FIG.

  An insertion hole 11k through which the inflow pipe 6 is inserted is formed in the upper part of the front wall portion 11a. A concave portion 11p for arranging the backwash drainage return pipe 8 is formed at the upper end portion of the rear wall portion 11b. An advection port 11r is provided on the upper left side of the rear wall portion 11b, and the advection port 11r passes through the partition wall 10 to communicate the solid-liquid separation unit 11 and the preliminary filtration tank 2. The lower part of the front wall part 11a is bent backward and inclined, and the lower part of the rear wall part 11b is bent forward and inclined, and between them, the solid-liquid separation part 11 and the sludge concentration storage part A lower opening 11q that communicates with 12 is formed. In addition, the lower part of the rear wall part 11b is extended below rather than the lower part of the front wall part 11a.

  Inside the solid-liquid separator 11, a partition plate 11j is disposed between the center front portion 15 and the center rear portion 16, and the center front portion 15 is provided with an inclined plate 11e below the insertion hole 11k. ing. A baffle plate 11f extending in a substantially vertical direction is disposed between the central front portion 15 and the central rear portion 16 and the right side portion 17, and the front portion 11u of the baffle plate 11f extends downward from the lower end of the inclined plate 11e. It is arrange | positioned so that it may extend. The reason why the corners 11s and 11s at the lower end of the baffle plate 11f are notched is to increase the flow area in the lower part and slow down the flow of water to be treated. Moreover, between the central front part 15 and the central rear part 16, and the left side part 18, it prevents that the to-be-processed water which flowed in flows out from the advancing port 11r without passing the lower part of the solid-liquid separator 11. FIG. Therefore, a baffle plate 11g extending in a substantially vertical direction is provided.

  In the preliminary filtration tank 2, as shown in FIG. 2, a filter bed 26 is formed by filling the center part sandwiched between the net members 23 and 24 with a filter medium to which anaerobic microorganisms are attached. . In addition, a baffle portion 21 is formed in the central portion of the rear portion of the preliminary filtration tank 2 by being partitioned by a partition wall 20 that partitions the carrier flow tank 3 and a partition wall 27 having a substantially U-shaped cross section. Has been. The lower end of the partition wall 27 is disposed above the bottom wall of the preliminary filtration tank 2, and the baffle portion 21 communicates with the lower portion 28 of the preliminary filtration layer 2 located below the filter bed 26.

  A fixed amount transfer device 22 that is a pumping means is fixed to the baffle portion 21 at a predetermined position by a fixing angle 29. The fixed-quantity transfer device 22 is a well-known air lift pump, and when the water level of the preliminary filtration tank 2 is lower than the low water level (LWL) shown in FIG. Transfer to 3. The fixed amount transfer device 22 is connected to a blower (not shown) via an air supply pipe P1. The pumping pipe 22a of the fixed-quantity transfer device 22 extends through the partition wall 20 to the carrier flow tank 3, and the outlet of the pumping pipe 22a is above the water level (WL) during normal operation of the carrier flow tank 3. It arrange | positions at the upper part of the support | carrier flow tank 3 so that it may become.

  Further, as shown in FIG. 1, the baffle portion 21 is provided with an overflow port 201 in the partition wall 20 for allowing the water to be treated that has overflowed when an abnormality such as a pump failure occurs to the carrier flow tank 3. As shown in FIG. 7, the lower edge position of the overflow port 201 includes a high water level (HWL) during normal operation of the preliminary filtration tank 2 and a water level (WW during normal operation of the carrier fluidized tank 3). .L.).

  The carrier fluid tank 3 is filled with a plastic carrier to which aerobic microorganisms adhere. The carrier has a shape (in the present embodiment, a gear shape) that makes it difficult to block an orifice 92 described later. Further, in the carrier flow tank 3, an air diffuser 32 is extended to the vicinity of the bottom. The air diffusion pipe 32 is connected to a blower (not shown) through an air supply pipe P1. A transfer pipe 9 as a circulation device is inserted into the partition wall 20 so as to extend in a substantially horizontal direction, and the carrier flow tank 3 and the prefiltration tank 2 are communicated with each other by the transfer pipe 9, that is, a secondary treatment. The tank S2 and the primary treatment tank S1 are in communication.

  As shown in FIG. 4, an orifice 92 and a rotating member 94 are provided in the inflow side portion 90 that is a portion on the inflow side of the transfer pipe 9. The transfer pipe 9 has a substantially circular cross section, a cap member 9a, a short pipe member 9b fitted to the cap member 9a, a long pipe member 9c connected to the short pipe member 9b, a short pipe member 9b and a long pipe member The connecting member 9d is connected to the cap member 9c, and the rotating member 94 is pivotally attached to the cap member 9a. A small-hole orifice 92 is formed in the cap member 9a.

  Specifically, as shown in FIGS. 4 and 5, the transfer pipe 9 is provided with an orifice 92 at the end surface 91 on the inflow side, and a portion other than the orifice 92 on the end surface 91 is closed. The opening surface of the orifice 92 has a shape and a size such that the carrier cannot pass (in this embodiment, a substantially elliptical shape with a concave upper edge). The end face 99 on the outflow side of the transfer pipe 9 is fully open.

  Further, the end surface 91 is provided with a rotating member 94 that rotates on the end surface 91 about the center 93 of the end surface 91. The rotating member 94 corresponds to a flow rate adjusting means. As shown in FIG. 5C, the rotating member 94 is a long and narrow plate-like member having a width slightly larger than the lateral width of the orifice 92 and capable of closing the orifice 92. The upper end portion (the upper end portion in the state of FIG. 5C) of the rotating member 94 is bent at a substantially right angle so as to be hooked on the upper surface 95 of the transfer tube 9 to form a guide portion 94a. As shown in FIG. 4A, a linear mark M1 is attached to the guide portion 94a, and a plurality of scales M2 are attached to the upper surface 95 so as to be aligned with the mark M1. The upper surface 95 is provided with an opening 96 for cleaning.

  As shown in FIG. 2, the transfer pipe 9 has an end surface 91 provided with an orifice 92 disposed in the carrier flow tank 3, and an end surface 99 having a high water level (HWL. ). Since the end surface 91 forms an angle of approximately 90 ° with respect to the horizontal plane, the opening surface of the orifice 92 forms an angle of approximately 90 ° with respect to the horizontal plane.

  In the partition wall 30, advection ports 33, 33 are opened on both upper side portions. The lower edge position of the convection ports 33 and 33 is a position slightly lower than the lower edge position of the orifice 92.

  In the biological filtration tank 4, a filter bed 45 is formed by filling a center part sandwiched between the net members 42 and 43 with a carrier attached with aerobic microorganisms. In addition, the central portion of the front portion of the biological filtration tank 4 is partitioned by a partition wall 30 that partitions the carrier flow tank 3 and a partition wall 46 having a substantially U-shaped cross section, thereby providing a treated water storage section. 41 is formed. The lower end of the partition wall 46 is disposed above the bottom wall of the biological filtration tank 4, and the treated water storage unit 41 is communicated with the lower part 47 of the biological filtration layer 4 located below the filter bed 45. As shown in FIG. 1, the partition wall 46 is provided with an overflow port 401 for escaping water that has overflowed in the event of an abnormality.

  The treated water storage unit 41 is provided with an air lift pump 48 for returning the backwash waste water, and the lower end portion of the air lift pump 48 is arranged in the lower part 47. In the biological filtration tank 4, a backwash pipe 49 is extended to the vicinity of the bottom through the treated water storage part 41. The air lift pump 48 and the backwash pipe 49 are connected to a blower (not shown) via an air supply pipe P2. Further, the backwash drainage return pipe 8 is connected to the air lift pump 48, and the backwash drainage return pipe 8 extends to the central rear part 16 of the solid-liquid separation part 11.

  A disinfection tank 5 is disposed above the treated water storage unit 41. A transfer pipe 51 is inserted through the rear wall of the treated water storage unit 41 and extends substantially in the horizontal direction, and the treated water storage unit 41 and the disinfection tank 5 communicate with each other. Both ends of the transfer pipe 51 are fully opened. The lower edge position of the inlet 51 a of the transfer pipe 51 is higher than the lower edge position of the inlets 33 and 33, and is higher than the upper edge position of the orifice 92. The lower edge position of the overflow port 401 is higher than the lower edge position of the inflow port 51a. A medicine cylinder 52 is disposed on the upper part of the sterilization tank 5. In the rear wall of the sterilization tank 5, a discharge pipe 7 for discharging the purified treated water is inserted. The lower edge position of the inlet 71 of the discharge pipe 7 is a position lower than the lower edge of the outlet 51 b of the transfer pipe 51. The discharge pipe 7 penetrates the rear wall of the tank T and extends outside the septic tank.

  Next, the operation of the septic tank configured as described above will be described. FIG. 6 shows the flow of treatment in the septic tank, and FIG. 7 shows the flow of water to be treated by arrows.

  First, the water to be treated flows from the inflow pipe 6 into the central front part 15 of the solid-liquid separation part 11. Then, the water to be treated flows down along the inclined plate 11e, that is, the water to be treated flows in the longitudinal direction of the solid-liquid separator 11 and reaches the right side portion 17 and sinks downward. At this time, since the water to be treated flows down along the inclined plate 11e and the flow speed becomes slow, the sludge stored in the sludge storage unit 12 is rarely rolled up.

  Relatively heavy impurities in the water to be treated fall from the lower opening 11q to the sludge concentration storage part 12. At this time, since the contaminants descend along the inclined lower portion of the front wall portion 11a and the lower portion of the rear wall portion 11b, the falling speed of the contaminants is slowed and sludge winding is suppressed.

  The fallen foreign matter is stored in the sludge concentration storage part 12 as sludge. Here, the lower opening 11q of the solid-liquid separation device 11 opens longer in the left-right direction of the septic tank, and the lower portion of the rear wall portion 11b extends below the lower portion of the front wall portion 11a and tilts forward. Therefore, sludge is deposited almost uniformly in the sludge concentration storage section 12, and the possibility of clogging due to sludge bias can be reduced.

  The treated water from which relatively heavy impurities have been removed by the solid-liquid separator 11 flows into the preliminary filtration tank 2 from the advection port 11r.

  The treated water that has flowed into the preliminary filtration tank 2 descends and passes through the filter bed 26, and the remaining contaminants are supplemented (physical filtration) by the filter medium in the filter bed 26, and decomposed by anaerobic microorganisms (anaerobic). It is processed. And it flows in into the baffle part 21 from the lower part 28, is pumped up by the fixed quantity transfer apparatus 22, and flows in into the support | carrier flow tank 3 from the pumping pipe 22a.

  The carrier fluid tank 3 is a tank in which an aeration process is performed. During normal operation, air is constantly ejected from the air diffuser 32, so that the carrier flows in the tank. The organic matter in the water to be treated is decomposed (aerobic treatment) by the aerobic microorganisms adhering to the carrier. Then, the water to be treated flows into the biological filtration tank 4 from the advection ports 33 and 33. Moreover, a part of to-be-processed water is returned to the preliminary filtration tank 2 through the orifice 92 so that it may mention later.

  The treated water that has flowed into the biological filtration tank 4 descends and passes through the filter bed 45, and suspended matter is captured (physical filtration) by the carrier in the filter bed 45, as shown by the light arrow in FIG. 7. Then, it enters the treated water storage section 41 and flows into the disinfection tank 5 from the outlet 51 b of the transfer pipe 51. In addition, in this specification, the to-be-processed water after the step which flowed into the treated water storage part 41 shall be called treated water.

  In the biological filtration tank 4, air is ejected from the backwash tube 49 once or twice a day to peel off the suspended matter captured by the carrier, and the water in the tank is pulled out by the air lift pump 48. The treated water in the treated water storage unit 41 is caused to flow backward, and the filter bed 45 is washed (backwashed). In addition, since the withdrawn backwash drainage contains a large amount of suspended solids, it is returned to the central rear portion 16 of the solid-liquid separator 11 by the backwash drainage return pipe 8 and reprocessed.

  In the sterilization tank 5, the treated water is sterilized with chemicals. The treated water after disinfection is discharged from the discharge pipe 7.

  Next, the water level of each tank will be described. The water level of the sludge storage tank 1 is determined by the lower edge position of the advection port 11r and becomes the position of W.L. in the sludge storage tank 1 shown in FIG. The lower edge position of the transfer port 11r is set higher than the high water level (HWL) in the preliminary filtration tank 2, and is lower than the lower edge position of the inlet 51a of the transfer pipe 51 provided in the treated water storage unit 41. Set low.

  The water level of the preliminary filtration tank 2 varies with time variation of the influent sewage, but is designed to vary in the range from the high water level (H.W.L.) to the low water level (L.W.L.) shown in FIG. This range is determined according to a predetermined standard, and the water level of the preliminary filtration tank 2 varies within this range during normal operation. Normal operation means when normal operation is performed under normal operating conditions, except when there is an abnormality such as a malfunction or when the user has used the product more than planned. Shall.

  The water level of the biological filtration tank 4 including the treated water storage section 41 is determined by the lower edge position of the inlet 51a of the transfer pipe 51, and the lower edge positions of the inlets 33 and 33 are higher than the lower edge position of the inlet 51a. Since it is low, the water level of the carrier fluidized tank 3 becomes the same level as the water level of the biological filtration tank 4 and becomes the position indicated by WL in the carrier fluidized tank 3 shown in FIG.

  And the end surface 99 of the transfer pipe 9 is higher than the high water level (HWL) in the preliminary filtration tank 2, the lower edge position of the inlet 51a of the transfer pipe 51 is the upper edge position of the orifice 92 of the transfer pipe 9, and Since it is higher than the lower edge position of the advection port 11r of the sludge storage tank 1, the water level of the carrier flow tank 3 is higher than the high water level (HWL) in the preliminary filtration tank 2, and moreover than the water level of the sludge storage tank 1. Also gets higher. That is, during normal operation, the secondary treatment tank S2 has a higher water level than the primary treatment tank S1.

  The water level of the disinfection tank 5 is a position that is lower by about 50 mm or more than the lower edge position of the outlet 51 b of the transfer pipe 51, and is determined by the lower edge position of the inlet 71 of the outlet pipe 7.

  Since the orifice 92 is disposed at a position lower than the lower edge position of the inflow port 51a, the orifice 92 is disposed at a position lower than W.L. in FIG. On the other hand, the end surface 99 of the transfer pipe 9 is disposed at a position higher than the high water level (HWL) in the preliminary filtration tank 2, so that the water to be treated in the carrier flow tank 3 through the orifice 92. A part of the water is returned to the preliminary filtration tank 2, and the water to be treated is constantly circulated without power by utilizing the water level difference.

  The flow rate of the water to be treated returned from the orifice 92 is determined by the opening area of the orifice 92 and the height from the orifice 92 to the water surface of the carrier flow tank 3. During normal operation, since the water level in the carrier fluidized tank 3 is substantially constant, the flow rate of the treated water returned from the orifice 92 is substantially constant, and the flow rate of the circulated treated water is substantially constant. The treatment becomes stable and the water quality becomes stable.

  In addition, since the orifice 92 is disposed in the carrier flow tank 3 in which the aeration process is performed, the orifice 92 is always washed by the carrier flowing in the tank, so that clogging with deposits hardly occurs. For this reason, the flow rate of the treated water to be circulated is kept substantially constant.

  Further, in general, in the septic tank, it is necessary to change the flow rate of the circulating water depending on the capacity (human tank), but as shown in FIG. 5, the circulating member 94 is rotated to change the opening area of the orifice 92. The flow rate of the water to be treated can be easily changed. In FIG. 5, (a) shows a 5-person tank, (b) shows a 10-person tank, and (c) shows a case where circulation is stopped.

  In the septic tank, confirmation, operation, cleaning, and the like are performed from the openings H1, H2, and H3 on the upper surface. As shown in FIG. 4, the rotating member 94 is provided with a guide portion 94a extending on the upper surface 95. Therefore, the rotation member 94 can be rotated by holding the guide portion 94a from above, and the degree of rotation can be confirmed by visually recognizing the position of the guide portion 94a from above, and adjustment is easy. In particular, if a mark M1 and a scale M2 are provided and these are combined, adjustment is easier. It should be noted that the scale M2 may be accompanied by a number indicating a human tank or capacity. The mark M1 and the scale M2 may be marks other than a line, and the scale M2 may be any mark indicating at least one of a human tank, a capacity, a flow rate, a rotation angle, or an opening area. What is necessary is just the mark for adjusting to the scale M2. The mark M1 may be a protrusion.

  As described above, the septic tank according to the present embodiment is configured so that the water level of the secondary treatment tank S2 is higher than the water level of the primary treatment tank S1 during normal operation, and the secondary treatment tank is transferred by the transfer pipe 9 using the water level difference. Since the water to be treated is returned from S2 to the primary treatment tank S1, it is not necessary to always operate the return pump, and the power can be reduced. In addition, by using the quantitative transfer device 22, a substantially constant amount of water to be treated per hour is transferred to the secondary treatment tank S2, so that the treatment is performed stably and the water quality is stabilized. As described above, since the flow rate of the circulating water is kept substantially constant by the orifice 92, the water quality can be stabilized.

  Moreover, by raising the water level of the secondary treatment tank S2, the capacity of the secondary treatment tank can be utilized to a maximum extent, and the septic tank can be downsized. And it is necessary to make the water level of the disinfection tank 5 lower than the water level of the secondary treatment tank S2, but if the water level of the secondary treatment tank S2 is increased, the water level of the disinfection tank 5 can also be raised, so it is connected to the disinfection tank 5. The position of the discharge pipe 7 can be increased (that is, the bottom of the discharge pipe 7 can be made shallow). For this reason, it becomes easy to give a gradient when connecting the discharge pipe 7 to a side groove or the like, and a pump for raising the position of the discharge pipe 7 is not necessary.

  Further, the solid-liquid separation device 11 is provided with the insertion hole 11k of the inflow pipe 6 in the front wall portion 11a along the longitudinal direction of the solid-liquid separation apparatus 11, so that the longitudinal direction of the solid-liquid separation apparatus 11 and the inflow pipe 6 are The inflow pipe 6 can be arranged so that the axial direction is substantially orthogonal. Here, the axial direction of the inflow pipe 6 substantially coincides with the longitudinal direction (front-rear direction) of the septic tank. That is, in the solid-liquid separation device 11, the longitudinal direction of the solid-liquid separation device 11 substantially coincides with the short direction (left-right direction) of the septic tank, and the short direction of the solid-liquid separation device 11 substantially coincides with the longitudinal direction of the septic tank. Thus, the space in the tank can be used effectively, and it can be installed in a septic tank with a small capacity and a short length in the front-rear direction. Further, as in the case where the longitudinal direction of the solid-liquid separator 11 is made coincident with the longitudinal direction of the septic tank, the solid-liquid separator 11 does not occupy substantially the entire surface of the opening H1 of the tank T in a plan view, It can be arranged with a slight offset with respect to the opening H1, and as shown by the symbol S in FIG. 1, since the space for cleaning the sludge concentration storage section 12 can be secured, the sludge concentration storage section 12 can be easily cleaned. is there. And since management, such as cleaning of the solid-liquid separation apparatus 11, is also possible from the opening part H1, the maintenance management of a septic tank becomes easy as a whole.

  In addition, by providing the solid-liquid separation device 11, a filter medium that has conventionally been arranged in the tank on the front side of the primary treatment tank for removing contaminants becomes unnecessary. No outflow of filter media due to inflowing water flow.

  In the present embodiment, the opening surface of the orifice 92 is set at an angle of approximately 90 ° with respect to the horizontal plane. However, this angle is 45 to 90 with respect to the horizontal plane so that the opening surface of the orifice 92 faces obliquely downward. It may be changed in the range of °. This is because when the opening surface of the orifice 92 faces obliquely downward, the orifice 92 is easily washed by the carrier and is more difficult to close. In order to change the angle of the opening surface of the orifice 92, the angle of the end surface 91 of the cap member 9a may be changed. Moreover, the shape of the orifice 92 may take various shapes such as a circle, an ellipse, a rectangle, or a combination of these shapes. Moreover, the rotation member 94 should just be able to open and close at least one part of the opening surface of the orifice 92 with a rotation angle.

  Further, the transfer pipe 9 may be disposed so as to be lowered toward the primary processing tank S1 without being disposed horizontally. Moreover, you may make it lengthen the transfer pipe | tube 9 and return circulating water to the sludge storage tank 1 which is the tank of the front part of primary treatment tank S1. Further, the return destination of the backwash waste water may be the central front portion 15 of the solid-liquid separator 11.

  Alternatively, the orifice 92 may be directly drilled in the partition wall 9 as a circulation device without providing the transfer pipe 9, but the orifice 92 is drilled in the transfer pipe 9, and the transfer pipe 9 is connected to the opening of the tank T. By disposing it directly under H2, adjustment operations and cleaning can be easily performed, and the circulating water can be returned directly above the filter bed 26 while avoiding the pump 22 and the baffle portion 21.

  Furthermore, in the septic tank of the present embodiment, the primary treatment tank S1 is composed of the sludge storage tank 1 and the preliminary filtration tank 2, and the secondary treatment tank S2 is composed of the carrier fluidization tank 3 and the biological filtration tank 4, The configuration of the primary treatment tank S1 and the secondary treatment tank S2 is not limited to this, and the primary treatment tank S1 is composed of an anaerobic filter bed first chamber and an anaerobic filter bed second chamber. Can also be composed of a carrier flow / biological filtration tank and a treated water tank for storing treated water. The carrier flow / biological filtration tank is a tank having a two-layer structure in which the upper part is a carrier flow tank 3 and the lower part is a biological filtration tank 4. Moreover, secondary treatment tank S2 can also be comprised from the biofilm filtration tank and the treated water tank equivalent to the treated water storage part 41 of this embodiment. The orifice 92 may be provided in the treated water tank that is the rear tank of the secondary treatment tank S2 or the treated water storage part 41 of the biological filtration tank 4.

  Further, a baffle plate extending in a substantially horizontal direction is disposed at the right end portion of the right side portion 17 of the solid-liquid separator 11 so as to connect the front wall portion 11a and the rear wall portion 11b while being in contact with the right wall portion 11c. It is good as well. Such a baffle plate suppresses sludge winding and changes the water flow in a substantially horizontal direction. Further, a baffle plate that extends in a substantially horizontal direction so as to connect the left wall portion 11d and the baffle plate 11g while being in contact with the rear wall portion 11b under the advancing port 11r of the left side portion 18 of the solid-liquid separator 11. It may be arranged. By such a baffle plate, the flow from right below is prevented, and a substantially horizontal water flow is formed. Thus, if the water flow direction is changed by the baffle plate, the flow path of the water to be treated can be lengthened, so that the separation performance can be improved.

  Furthermore, the angle formed by the longitudinal direction of the solid-liquid separation device 11 and the longitudinal direction of the septic tank is preferably about 90 ° in plan view as in the present embodiment from the viewpoint of effective use of space, but about 90 ° in plan view. An angle of 45 ° or more and about 90 ° or less (that is, from the state where the longitudinal direction of the solid-liquid separation device 11 coincides with the longitudinal direction of the septic tank, the solid-liquid separation device 11 is rotated about 45 ° or more and about 90 ° or less in the horizontal direction. If it is the state), the cleaning space of the sludge concentration storage part 12 can be secured, and the maintenance management of the septic tank becomes easy.

  That is, the present invention can adopt various configurations without departing from the scope of the claims.

It is a schematic cross-sectional view of one embodiment of the septic tank of the present invention. It is a schematic longitudinal cross-sectional view of the septic tank of FIG. It is a schematic perspective view of the solid-liquid separator which displayed the front wall part and the right wall part with the dashed-two dotted line. (A) is a top view of a transfer pipe, (b) is sectional drawing of a transfer pipe. It is a rear view of a transfer pipe, (a) is a 5-person tank, (b) is a 10-person tank, and (c) is a state where an orifice was closed. It is a figure which shows the flow of a process of the septic tank of FIG. It is a figure which shows the flow of the to-be-processed water of the septic tank of FIG. It is a schematic longitudinal cross-sectional view of the conventional septic tank.

Explanation of symbols

1 Sludge storage tank (first room)
6 Inflow pipe 9 Transfer pipe (circulation device)
11 Solid-liquid separator 22 Fixed-quantity transfer device (pumping means)
90 Inflow side 91 End face 92 Orifice 93 Center 94 Rotating member (flow rate adjusting means)
94a Guide part S1 Primary treatment tank S2 Secondary treatment tank

Claims (2)

In the septic tank whose interior is partitioned into multiple chambers,
A solid-liquid separation device is provided at the top of the first chamber (hereinafter referred to as the first chamber) counted from the upstream side to substantially separate the solid matter in the water to be treated and drop it to the lower portion of the first chamber.
A septic tank characterized in that the sewage water flows into the solid-liquid separator from an inflow pipe through which the sewage water flows into the septic tank. A primary treatment tank in which the first chamber is provided to primarily treat the treated water;
A secondary treatment tank for secondary treatment of the treated water subjected to the primary treatment;
Pumping means for pumping water to be treated from the primary treatment tank to the secondary treatment tank;
Have
The septic tank according to claim 1, wherein, during normal operation, the secondary treatment tank is set to a higher water level than the primary treatment tank by the pumping means.

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