JP2006075839A5 - - Google Patents

Description

Wastewater septic tank

  The present invention relates to a sewage purification tank for treating organic sewage, and more particularly, to a primary treatment method and apparatus for organic sewage that contributes to downsizing and compactness of a primary treatment tank that performs the primary treatment.

  Conventionally, in order to primarily treat organic sewage flowing into the sewage septic tank, an anaerobic filter bed equipped with a sediment separation tank (also called a contaminant removal tank) that separates and separates the inflow sewage, and an anaerobic filter bed that anaerobically treats it. The combination of the tank and the combination of the first chamber and the second chamber of the anaerobic filter bed equipped with the anaerobic filter bed remove solid matters, solids, suspended solids, etc. Liquid sludge treatment, sludge generated in the primary treatment, contact aeration tank and sedimentation tank in the secondary treatment process, or the specification and drawings of Japanese Patent Application No. 10-180388 related to the prior application In addition, the return sludge generated in the secondary treatment process such as a biological filtration tank filled with a fluidized bed filter medium and a treated water tank is stored.

  However, in the case of this kind of sewage septic tank, the pumping process once per year is obligated, and the processing performance that sufficiently maintains the roles of the solid-liquid separation function and the sludge storage function is guaranteed. Moreover, since the treatment of organic sewage in recent years is intended for the combined treatment of domestic wastewater including manure sewage, the capacity of the sewage septic tank is much larger than the conventional single septic tank. .

  However, when considering the housing situation in Japan, it may be difficult to embed an enlarged sewage septic tank in a limited installation space, and when considering replacement with an existing single septic tank, It is required to ensure that the sewage septic tank with a larger size is equal to or smaller than the capacity of a conventional single septic tank, and the processing performance is equal to or higher than that.

On the other hand, in the patent publication related to Japanese Patent No. 2568729, the agglomeration tank for anaerobically stirring the inflowing anaerobic sewage and the agglomerated floc are submerged to the settling tank and the sludge floc is returned to the agglomeration tank. A sewage treatment device is proposed, which has a comparatively simple structure, excellent cohesiveness, reduced generation of excess sludge, and the superiority of the structure that is excellent in primary treatment of organic sewage. Proven.
Japanese Patent No. 2568729

  However, in the sewage treatment apparatus shown in the above-mentioned patent gazette, daily wastewater flows into the coagulation tank in a relatively short time, or an actual wastewater septic tank in which manure sewage having a density different from that flows randomly. However, in order to incorporate it as it is, it is necessary to solve the following problems.

  For example, when sewage with different density and specific gravity, such as domestic wastewater and manure sewage, or influent sewage with a high density flows in from the inlet of a flat bottomed coagulation tank, the inflow sewage flows into the coagulation tank vertically. This causes the phenomenon of `` bottom density flow '' that circulates from the wall to the sedimentation tank and transfers it to the sedimentation tank.Therefore, anaerobic sludge is sent to the sedimentation tank more than necessary, or stirring and mixing by anaerobic sludge is not required. If it is sent to the next secondary processing step in a sufficient situation, it causes the occurrence of processing spots in the primary processing or causes variations in processing performance in the secondary processing.

  Therefore, in order to prevent the above-described adverse effects, there is a need to increase the capacity of these primary treatment tanks and to increase the depth of the water, and the present invention intends to reduce the capacity of the primary treatment tank. It will not be along.

  Further, in the sewage treatment apparatus shown in the above-mentioned patent publication, anaerobic stirring in the coagulation tank is mechanically performed by the submerged stirring blade and the water surface stirring blade, or the surface of the sewage treatment apparatus floats on the settling tank. Although the technical content of collecting the collected scum with a scum collector is disclosed, in practical use, these points can be handled in a maintenance-free manner, and the sludge flocs that have settled after being agglomerated can be effectively reduced in volume. The need to take appropriate measures is recognized.

Therefore, in the present invention, a rational sewage septic tank different from the structure of the sewage treatment apparatus described in the above-mentioned patent publication is provided.

Specifically, as described in claim 1, a sewage purification tank comprising a biological filtration tank filled with a fluidized bed carrier and a baffle wall separation tank provided upstream from the biological filtration tank. The baffle wall separation tank is partitioned by a first baffle wall, a second baffle wall provided downstream of the first baffle wall, and the first baffle wall and the second baffle wall. A separation chamber, a scum baffle wall formed on the upper side of the baffle wall in each of the first baffle wall and the second baffle wall, and sludge formed on the lower side of the baffle wall And a convection opening formed between the scum barrier wall and the sludge barrier wall, the scum barrier wall floating in the treated water upstream of the scum barrier wall. The scum accumulated in the state is prevented from flowing out to the downstream side of the scum blocking wall, and the sludge blocking wall is the sludge blocking wall. The sludge floc and sediment sludge contained in the upstream treated water are prevented from flowing out to the downstream side of the sludge baffle wall, and the advection port and the second baffle in the first baffle wall The advection ports in the wall are formed at the same height so that the treated water is advected in the horizontal direction in the separation chamber .

According to a second aspect of the present invention, the baffle wall separation tank according to the first aspect is formed at a lower part of the latent flow partition and a latent flow partition that divides the downstream region of the second baffle wall in a plane U shape. An overflow port formed between the latent flow port, a rear advection chamber formed on the rear side of the latent flow partition, and the biological filtration tank, and the second obstruction by moving the separation chamber in a horizontal direction. The treated water that flows out from the advection port of the wall to the downstream region of the second baffle wall flows into the advection chamber from the latent flow port and once rises up the advection chamber, and then from the overflow port to the biological filtration tank. It is configured to overflow into the river .

According to the present invention, the first baffle wall and the second baffle wall that define the baffle wall separation tank can prevent the outflow of scum, sludge flocs, and accumulated sludge. Provided is a rational sewage septic tank that can particularly prevent the outflow of sludge flocs by the combination of the second baffle wall and the latent flow partition, the latent flow port, the advection chamber, and the overflow port.

  Hereinafter, the embodiment of the present invention will be described based on a longitudinal sectional view and a plan view of the septic tank T shown in FIGS. 1 and 2, a partially cutaway perspective view of the anaerobic contact tank of FIG. To do.

  The inside of the sewage septic tank T is divided into a plurality of treatment tanks according to the order of the sewage treatment process from the inflow pipe 1 side into which organic sewage such as manure sewage and domestic wastewater flows into the treated water discharge pipe 2 side. Specifically, an anaerobic contact tank A on the inflow pipe 1 side and a baffle wall separation tank B in which the inside of the tank is divided into three separation chambers B1, B2, and B3 by baffle walls 3 and 4 are provided. A primary treatment tank, a biological filtration tank C filled with a fluidized bed carrier V, and a secondary treatment tank provided with a treated water tank D and a disinfection tank E.

  The anaerobic contact tank A has a width of about half of the width of the septic tank T and a vertical overflow wall 6 and left and right side walls 7 at a central position inside the main body front wall 5 of the sewage septic tank T. The lower half of the overflow partition wall 6 is an inclined bottom wall 8 formed so as to be forwardly lowered toward the lower end corner of the main body front wall 5, and the lower half of the side wall 7 is The body front wall 5 and the inclined bottom wall 8 have a substantially V-shaped, wedge-shaped wall shape, and the tank bottom portion of the anaerobic contact tank A is substantially V-shaped, wedge-shaped, or hopper-shaped. It is in the form of stenosis. Accordingly, an appropriate amount of anaerobic sludge X that becomes seed sludge when being agglomerated is intensively collected and stored in the bottom of the anaerobic contact tank A, and the anaerobic sludge X and the influent sewage The anaerobic sludge X is floated and dispersed at the time of mixing or stirring and mixing with the fumarole.

  Reference numeral 9 is an inflow guide pipe connected to the rear end of the inflow pipe 1, and the lower end of the inflow guide pipe is inclined obliquely toward the front side so as to be near the upper and lower middle of the main body front wall 5 of the sewage septic tank T. Yes. 10 is an outlet formed in the left and right sides of the lower end portion of the inflow guide tube 9, 11 is a rectifying plate for closing the lower end portion of the inflow guide tube 9, and inflow sewage flowing down the inflow guide tube 9 is While colliding with the current plate 11 and reducing its inflow force, it is divided into a lateral direction including the left and right oblique directions of the anaerobic contact tank A and flows out from the immediately preceding outlet 10.

  12 is a latent flow partition that divides the anaerobic contact tank A into the front and rear, and the front side thereof is about two-thirds in plan view, the contact chamber A1 having a capacity of about three-quarters, and the rear side is three minutes. A partition is formed in the advection chamber A2 having a capacity of about 1 and a quarter of the capacity. Reference numeral 13 denotes a latent flow port opened between the lower end portion of the latent flow partition wall 12 and the inclined bottom wall 8, and reference numeral 14 denotes an advection port opened at a height position above the intermediate portion of the latent flow partition wall 12. An opening is formed in the water below the water level line WL of the anaerobic contact tank A at a position above the height of the outlet 10 of the pipe 9.

  15 is an air diffuser piped to the bottom of the constricted tank of the contact chamber A1, and 16 is an air supply pipe descending along the inner wall surface of the contact chamber A1, which is anaerobic stored in the tank bottom by these blower devices. The stored anaerobic sludge Z is intermittently levitated toward the upper part of the tank by injecting into the sludge X intermittently, specifically, for a very short time of about 3 to 5 seconds every 30 minutes. Disperse. Then, anaerobic sludge X that rises and disperses, anaerobic sewage that stays in the contact chamber A1, and newly mixed organic sewage are efficiently stirred and mixed, so that the cohesiveness to sewage and sludge is dramatically increased. As a result, the sedimentation rate of the coagulated sludge floc is remarkably increased, and specifically, the measured sedimentation rate is 10 CM / MIN or more.

  In the case described above, the anaerobic sludge X is agitated by the fumarole from the maintenance-free fumarole apparatus, but the fumarole duration is extremely short and intermittent. Therefore, the anaerobic property in the tank of the anaerobic contact tank A is properly maintained, and the inhabitants of the anaerobic microorganisms are not impaired.

  Thus, the coagulated sludge floc Y slowly settles down to the bottom of the contact chamber A1 and moves to the advection chamber A2 from the latent flow port 13 of the latent flow partition 12 along with a new inflow of sewage. It flows into the first separation chamber B1 of the next baffle wall separation tank B through the overflow port 17 opened on the water level line WL of the flow partition 6.

  Further, a part of the sludge floc Y that has flowed into the advection chamber A2 does not pass through the overflow port 17 and settles down in the advection chamber A2 and accumulates in the inclined bottom wall 8, and eventually in the inclined bottom wall 8 By sliding down along, it is returned to the bottom of the contact chamber A1, that is, the bottom of the anaerobic contact tank A. As a result, an appropriate amount of anaerobic sludge X is always stored as anaerobic contact seed sludge at the bottom of the anaerobic contact tank A, and this is mixed well with the inflow sewage, or intermittently from the fuming device. By being lifted and dispersed by the blowing action, the stirring and mixing with the sewage in the contact chamber A1 is repeated. Thus, the agglomeration process is repeated for the sludge that flows into the anaerobic contact tank A, the stored sludge, and other solid content and SS content, and is agglomerated to a sludge floc having a high sedimentation speed.

  In the above case, the inflowing sewage passing through the inflow guide pipe 9 is weakened by the rectifying plate 11 so that it does not flow straight down as it is, and the outflow direction from the outflow port 10 is inclined left and right. Directionality is given so as to be substantially horizontal including the direction. Therefore, anaerobic sludge Z stored at the bottom is prevented from being sent out from the advection chamber A2 to the baffle wall separation tank B by the bottom density flow caused by the inflow sewage flowing into the bottom of the contact chamber A1 at a stretch. Thus, an appropriate amount of anaerobic sludge X is constantly maintained.

  Of course, the inflowing sewage containing the manure that flows out from the outflow port 10 almost laterally begins to settle slowly, mixes appropriately with the anaerobic treatment water that has been subjected to the agglomeration treatment before, and the squirting action from the squirting device causes the tank to Aggregating treatment with high efficiency is performed by stirring and mixing with the anaerobic sludge X which is dispersed and floats inside.

  In the above case, the action in the case where the inflowing sewage is human waste has been mainly described. However, the inflowing sewage to the anaerobic contact tank A is drained in a large amount in a relatively short time such as bath water and washing water. In the case of the domestic wastewater that is produced, most of the inflow is provided for coagulation contact with the anaerobic sludge X in the same manner as in the case of the above-mentioned manure. The part rises upward from the outlet 10 without sinking, and a part thereof flows from the advection port 14 of the latent flow partition 12 into the advection chamber A2. That is, after the latent flow port 13 is short-cut and directly flows into the advection chamber A <b> 2, it passes over the overflow port 17 of the overflow partition 6 and is sent to the first separation chamber B <b> 1 of the next baffle wall separation tank B. Accordingly, by bypassing the shortcut advection port 14 described above, the anaerobic sludge X stored at the bottom of the contact chamber A1 is pushed out more than necessary due to domestic wastewater flowing in a large amount in a relatively short time. I am trying not to. In particular, in the case of domestic wastewater, since the degree of contamination of inflow sewage is usually low and the load is small, it is possible to cope with efficient primary treatment with respect to inflow sewage by transferring the advection port 14 as a shortcut. ing.

  Next, the baffle wall separation tank B is divided into three chambers of a first separation chamber B1, a second separation chamber B2, and a third separation chamber B3 by the first baffle wall 3 and the second baffle wall 4. The first separation chamber B1 is laid out in a U-shape so as to surround three sides of the anaerobic contact tank A, and the relatively small-capacity anaerobic contact tank A is part of the zone of the first separation chamber B1. It is built in.

  The first baffle wall 3 is provided at the boundary between the first separation chamber B1 and the second separation chamber B2, and at a height position on the upper side from the intermediate portion, the first baffle wall 3 is 70 of the water level line WL of the baffle wall separation tank B. An advection port 18 is opened in the underwater portion at a depth of about -80%, and a communication port 19 is formed at the lower end portion in consideration of convenience when pumping up the accumulated sludge. If the lower portion and the upper portion of the first baffle wall 3 from the advection port 18 are described based on the functions described later, the lower portion of the first baffle wall 3 extends from the overflow port 17 to the first separation chamber B1. In the sludge blocking wall 3B for preventing the sludge floc Y contained in the treated water flowing into the water from flowing out and settling in the first separation chamber B1 and preventing the accumulated sludge from being anaerobically treated to be stored. There is a scum blocking wall 3A for preventing the outflow of the scum Z accumulated in a floating state in the surface layer portion of the first precipitation chamber B1. Moreover, in the case of the advection port 18 opened to the 1st baffle wall 3, the treated water which flowed into the 1st separation chamber B1 from the overflow port 17 and the treated water anaerobically treated in the said 1st separation chamber B1 are used. Also, it has a role to regulate or control the outflow direction for flowing into the next second separation chamber B2 as a substantially horizontal flow.

  In the above case, the advection port 18 is formed at a position above the tank middle position of the first first baffle wall 3, but the upper side is a single scum baffle wall 3A and the lower side is a single baffle. By dividing each by the sludge blocking wall 3B, the advection port 18 can also be formed as a result between the lower end part of the scum blocking wall 3A and the upper end part of the sludge blocking wall 3B. In addition, the upper scum baffle wall 3A can be slightly moved forward as compared to the lower sludge baffle wall 3B, and the advection port 18 can be formed therebetween.

  Further, the second baffle wall 4 is provided at the boundary between the second separation chamber B2 and the third separation chamber B3, and the advection port 20 is opened in water at substantially the same depth as the advection port 18. A communication port 21 is formed at the lower end portion in consideration of the convenience at the time of pumping the accumulated sludge in the same manner as described above. The lower part and the upper part of the second baffle wall 4 from the advection port 20 will be described based on the function in the same manner as described above. Sludge blocking flow for preventing the sludge flock Y contained in the treated water flowing in the horizontal flow in the second separation chamber B2 from flowing out, and preventing the stored sludge from flowing out in the second separation chamber B2 The upper part of the wall 4B is a scum blocking wall 4A for preventing the scum Z floating on the surface layer of the second separation chamber B2 from flowing out.

  In the above case, the advection port 20 is formed at a position above the tank middle position of the single second baffle wall 4. However, as in the above case, the upper side is a single scum baffle wall 4A. Thus, by dividing each lower side by a single sludge baffle wall 4B, the advection port 20 is consequently formed between the lower end portion of the upper baffle wall 4A and the upper end portion of the lower baffle wall 4B. Can also be formed. Furthermore, the scum baffle 4A on the upper side can be slightly moved forward toward the front side of the sludge baffle 4B on the lower side, and the advection port 20 can be formed between them.

Further, the opening height of the advection port 20 and the distance between the sludge baffle wall 3B in the first baffle wall 3 and the sludge baffle wall 4B in the second baffle wall 4 are sludge that has been agglomerated in the anaerobic contact tank A. The relationship between the sedimentation speed of the flock Y and the advection speed that flows into the second separation chamber B2 from the advection port 18 and flows upward from the middle portion of the second separation chamber B2, that is, the upper layer flows as a horizontal flow. Determined by For example, in the above-described baffle wall separation tank B, in particular, the advancing speed of the treated water that flows in a horizontal flow from the first baffle wall 3 to the second baffle wall 4 is obtained by V = Q / A. Here, when the opening of the advection port 18 of the first baffle wall 3 has a height of 10 CM and a width of 70 CM, the opening area of the advection port 18 is 0.1 × 0.7 M ^2. . Further, it is assumed that a maximum of 250 L of treated water flows from the advection port 18 in 12.5 minutes. When these numerical values are substituted, the advection velocity V = 0.250 / 12.5 × 0.1 × 0.7 = 0.286... About 30 CM / MIN. On the other hand, since the sedimentation rate of the sludge floc Y that has been agglomerated as described above is 10 CM / MIN from the experimental results, if the interval between the first baffle wall 3 and the second baffle wall 4 is 30 CM or more, In addition, the sludge floc settles over 10CM. Then, temporarily, one of the sludge flocs Y contained in the treated water flowing in from the advection port 18 of the first baffle wall 3 is directed from the upper edge of the advection port 18 toward the advection port 20 of the second baffle wall 4. As it flows as a horizontal flow, it sinks by 10 cm or more, so that it does not flow out of the advection port 20 opened to almost the same height as the advection port 18 but is captured by being settled in the second separation chamber B2. .

  In FIGS. 1 and 2 and FIG. 4, reference numeral 22 denotes a latent flow partition wall in which the rear upper position of the third separation chamber B3 is partitioned in a plane U shape, and 23 is a transfer chamber formed on the rear side of the latent flow partition wall 22. , Between the underflow partition wall 22 and the overflow partition wall 24 of the next secondary treatment tank. Reference numeral 25 denotes a rearward tilt formed on the lower end portion of the submerged partition wall 22 so as to be inclined obliquely rearwardly, and reference numeral 26 denotes a forward tilter provided so as to project obliquely forwardly downward toward the rearward tiltable wall 25. 24 is fixed. Reference numeral 27 denotes a latent flow port formed between the rear tilting ridge 25 and the front tilting ridge 26, which prevents the sludge flock Y from flowing out from the third separation chamber B3 and raises the advection chamber 23 once. The sludge flock Y that settles or sinks or sinks without overflowing the overflow port 28 formed in the overflow partition wall 24 slides down to the third separation chamber B3 and proceeds to the secondary treatment step. The sludge flock Y is prevented from being taken out.

  Thus, the anaerobic treated water containing the sludge flock Y flowing into the first separation chamber B1 from the overflow port 17 of the anaerobic contact chamber A once flows into the first separation chamber B1 and flows by an appropriate flow in the tank. At the same time, the anaerobic treated water in the first separation chamber B1 flows out from the advection port 18 opened at a height position above the intermediate portion of the first baffle wall 3. At that time, a part of the sludge floc Y contained in the anaerobic treated water heading toward the advection port 18 of the first baffle wall 3 sinks toward the advection port 18, or by the first baffle wall 3. Since the advection passage from the advection port 18 is blocked, the liquid settles on the tank bottom of the first separation chamber B1. Anaerobic microorganisms adhere to the settled sludge flock Y, and the sludge content is gradually reduced by being subjected to anaerobic treatment on the sludge flock Y. Then, the sludge content O after the anaerobic treatment is gradually accumulated and stocked at the bottom of the first separation chamber B1 as shown in FIG.

  On the contrary, the scum Z in the sludge flock Y is blocked by the scum blocking wall 3A on the upper side of the advection port 18 and floats to the surface layer portion of the first separation chamber B1, and the first separation chamber B1. Collected at the surface layer portions on both the left and right sides of the anaerobic contact tank A, which has little influence on the outflow from the water, and gradually floats and accumulates in a consolidated state.

  Subsequently, the anaerobic treated water containing the sludge flock Y flowing into the second separation chamber B2 from the advection port 18 of the first baffle wall 3 is opened at a position substantially the same depth as the advection port 18. In this case, the sludge floc Y contained in the anaerobic treated water is gradually settled toward the advection port 20 or flows into the advection port 20 of the wall 4. Outflow is blocked by the sludge blocking wall 4B on the lower side of the liquid and settles. Of course, a part of the anaerobic treated water that has flowed into the second separation chamber B2 is mixed by an appropriate flow in the tank formed along with the flow into the second separation chamber B2. Therefore, the outflow from the advancing port 20 of the second baffle wall 4 is prevented, so that the sludge floc Y settled on the bottom of the second separation chamber B2 is subjected to anaerobic treatment by anaerobic microorganisms as described above. As a result, the volume of sludge is gradually reduced. Then, the sludge content O after the anaerobic treatment is gradually accumulated and stocked at the bottom of the second separation chamber B2 as shown in FIG. On the contrary, the scum Z in the sludge flock Y gradually rises to the surface layer portion of the second separation chamber B2, or rises by being blocked by the scum baffle wall 4A on the upper side of the advection port 20, 2 It gradually accumulates in the surface layer part of the separation chamber B2 and floats and accumulates.

  The anaerobic treated water flowing into the third separation chamber B3 from the advection port 20 of the second baffle wall 4 flows into the third separation chamber B3 and is mixed by an appropriate flow in the tank. The anaerobic treated water in the three separation chamber B3 flows into the advection chamber 24 from the latent flow port 27 between the rear tilting ridge 26 of the latent flow partition 22 and the forward tilting 26 projecting from the overflow partition 24 of the next tank C. From the overflow port 28, it is sent to the next secondary processing step. At that time, the anaerobic treated water that has flowed into the third separation chamber B3 and the sludge floc Y contained therein are introduced into the latent flow outlet 22 by the latent flow partition wall 22, the back tilt 25 of the lower end thereof, and the forward tilt 26 of the overflow partition 24. Ascending passage from 27 is blocked and settles to the bottom of the tank, and is subjected to anaerobic treatment to gradually reduce the volume of sludge. Then, the sludge content O after the anaerobic treatment is gradually accumulated and stocked at the bottom of the third separation chamber B3 as shown in FIG. In addition, the scum Z gradually rises to the surface layer portion of the third separation chamber B3, gathers at the surface layer portion, and gradually becomes a compacted state and is stocked.

  As described above, the first baffle wall 3 and the second baffle wall 4 provided in the baffle wall separation tank B rectify and flow the anaerobic treated water containing the sludge floc Y in the horizontal direction, Unlike the case of the sedimentation separation tank, the generation of bottom density flow is prevented, the sedimentation sludge is prevented from being rolled up, and the effect of the blocking wall such as prevention of re-floating of the sedimentation sludge is exhibited. Solid-liquid separation with respect to the primary treated water in the baffle wall separation tank B is efficiently performed. In addition, the sludge separated from the solid and liquid and precipitated at the bottom of the tank is subjected to anaerobic treatment by anaerobic microorganisms flowing out from the anaerobic contact tank A, thereby significantly reducing the volume of the sludge. As a result, the primary treatment performance of organic sewage is remarkably enhanced, and the volume reduction of sludge can be dramatically improved, so that the primary treatment tank is remarkably reduced in size and size. In particular, at that time, the treated water flowing from the advection port 18 flows in a substantially horizontal flow, so that a bottom density flow due to the treated treated water does not occur, and the accumulated sludge O that has been anaerobically treated is rolled up and advected. It is not taken out from the mouth 20. As a result, the deposited sludge O after the anaerobic treatment is placed at the bottom of each chamber B1 to B3 of the baffle wall separation tank B at the lower imaginary line shown in FIG. 1 (for example, a virtual line when 3 to 4 months have elapsed). After being accumulated gradually like an imaginary line (for example, an imaginary line when 10 to 12 months have elapsed), the pumping is handled once a year.

  In the above-mentioned embodiment, the case where the number of persons to be treated is a standard specification of about 5, 6 to 10 persons is targeted, and the baffle wall separation tank B is formed by the first baffle wall 3 and the second baffle wall 4. Although the case where it is divided into three rooms has been described, in the case where the number of persons to be processed is relatively small, such as about 5 or less, the baffle wall separation tank B is divided into two baffles 4 by one baffle wall 4. It can also be dealt with by dividing it into rooms. For example, in the case of the balance of tank capacity as shown in FIGS. 1 and 2, the first blocking wall 3 shown in FIGS. 1 and 2 is eliminated, and the blocking wall separation tank B is formed only by the second blocking wall 4. Can be divided into two chambers. Conversely, in the case of a sewage septic tank where the number of persons to be treated is more than the standard specification case, the number of partition walls of the baffle walls 3 and 4 in the baffle wall separation tank B is appropriately increased to 3 or more. By doing so, the sludge floc Y is settled in multiple stages.

  In the above-described case, the advection ports 18 and 20 are opened in the water above the middle portion of the baffle walls 3 and 4, and the scum baffle walls 3A and 4A above the advection ports 18 and 20 are used. Although the scum Z is prevented from flowing out, the flocculation effect due to the anaerobic sludge X in the anaerobic contact tank A becomes more efficient, and when the sedimentation rate of the sludge floc Y increases dramatically, the floating scum The generation of Z is remarkably suppressed. In such a case, the scum baffle wall 4A on the upper side from the advection port 20 in the second baffle wall 4 out of the first baffle wall 3 and the second baffle wall 4 is not necessary. For example, the underwater portion from the depth position corresponding to the advection port 20 to the lower side may be a baffle wall separation tank B having a structure defined by only the sludge baffle wall 4B as shown in FIG. In this case, the primary treated water flowing in from the advection port 18 of the first baffle wall 3 of the baffle wall separation tank B becomes a horizontal flow from the second separation chamber B2 to the upper layer portion of the third separation chamber B3. When flowing, sludge flock Y contained in the primary treated water is prevented from flowing out by the sludge blocking wall 4B that partitions both chambers B2 and B3 in the underwater portion, and the sedimentation thereof is promoted. Of course, the scum Z generated slightly stays in the surface layer portion of the third separation chamber B3 from the second separation chamber B2 and is stocked, and does not flow out by being blocked by the advancing partition wall 22 of the third separation chamber B3.

  In the above-described embodiment, the anaerobic contact tank A is a tank structure in which the anaerobic contact tank A is incorporated in the first separation chamber B1 of the baffle wall separation tank B. As a modification thereof, as shown in the plan view of FIG. In addition, the overflow partition 16 of the anaerobic contact tank A is formed by partitioning the main body side wall of the sewage purification tank T from side to side, and the advection partition 12 is bent in a plane arc shape along with it, and the fumes in the contact chamber A1 An anaerobic contact tank A having a structure in which the tube 15 is bent in an arc shape may be used. In short, the layout of the anaerobic contact tank A as shown in FIGS. 7 and 8 does not change the gist of the present invention.

  Next, details of the biological filtration tank C constituting the secondary treatment apparatus are disclosed in Japanese Patent Application No. 10-180388. The biological filtration tank C has the following configuration.

  First, an upper perforated plate 30 for preventing floating of a fluidized bed carrier V (hereinafter also simply referred to as a carrier) and a lower perforated plate 31 for preventing sedimentation are passed between an upper part and a lower part of the biological filtration tank C. Yes. 32 is an air diffuser, and is arranged in a lattice pattern at a position near the lower porous plate 31 between the biological treatment chambers partitioned by the upper porous plate 30 and the lower porous plate 31, The fluidized bed carrier V is packed in an amount of about 70 to 80% of the capacity. Reference numeral 33 denotes a bottom chamber of the biological filtration tank C, and a backwash pipe 34 is piped above the chamber. Reference numeral 35 denotes a latent flow partition wall to the treated water tank D, and aerobic treated water latent flow ports 36 are opened on both left and right sides of the lower end portion thereof.

  Reference numeral 37 denotes a return air lift pipe that pumps backwash water at the time of backwashing. An inlet 38 at the lower end of the airlift pipe is inserted from a latent inlet 36 on one side so as to face the center of the bottom chamber 33, and The tip discharge port of the sewage return pipe 39 connected to the upper end portion faces the contact chamber A1 of the anaerobic contact tank A. Reference numeral 40 denotes an air lift pipe for circulating aerobic treated water that has been subjected to secondary treatment, and is erected at the other side position of the back surface of the latent flow partition wall 35. The front discharge port of the circulation return pipe 42 connected to the upper end portion of the circulation return pipe 42 faces the first separation chamber B1 of the baffle wall separation tank B and is subjected to denitrification treatment of the primary treated water.

  Thus, the primary treated water which has been subjected to multistage treatment in the baffle wall separation tank B and has flowed into the biological filtration tank C from the overflow port 28 of the overflow partition wall 24 is diffused by the diffused stirring action from the diffuser pipe 32. The fluidized bed carrier V in the aerobic treatment zone M on the upper side from the trachea 32 is gently fluidized and biologically treated by aerobic microorganisms attached to the surface of the carrier V or inside the carrier X. In addition, the flowing carriers V come into contact with each other, adhere to the surface of the carrier V, and the biofilm formed by the microorganisms is appropriately peeled off to be maintained in an appropriate amount.

  Next, the aerobic treated water that has been biologically treated by aeration agitation is suspended in the aerobic treated water or the carrier in the filtration treatment zone N by the carrier V filled in the lower side of the aeration tube 32. A physical filtration process is performed by capturing an excessive biofilm peeled from V and other SS components. The treated water that has passed through the filtration treatment zone N descends into the bottom chamber 33 of the biological filtration tank C, and then flows through the latent flow ports 36 formed on the left and right sides of the latent flow partition wall 35 to the next treated water tank D. Sent out.

  At midnight when there is no inflow of sewage, a backwash blower (not shown) is driven and aeration from the backwash pipe 34 of the bottom chamber 33 is ejected. Then, first, the carrier V in the filtration treatment zone N starts to flow at a stretch by the aeration action from the backwash tube 34, and the sludge accumulated in the carrier V in the filtration treatment zone N and inside the carrier V The SS component is fluidized, and moreover it is subjected to fluid aeration and agitation as compared to the normal agitation and agitation, and fluid contact is performed, so that the back washing process for the carrier V in the filtration zone N is performed.

  Backwash treated water containing excess biofilm, sludge, SS, etc. separated by backwash treatment is pumped from the inlet 38 of the return air lift pipe 37, and the contact chamber of the anaerobic contact tank A from the sewage return pipe 39. Returned to A1 for reprocessing. At that time, a slight amount is pumped up from the inlet 41 of the circulation air lift pipe 40 and is returned to the first separation chamber B1 of the baffle wall separation tank B.

  At the time of the backwashing, a part of the carrier V in the filtration processing zone N floats to the upper side of the aeration tube 32 and swirls, and a part of the carrier V in the aerobic treatment zone M is in the aeration tube 32. By the sedimentation flow to the lower side, the carrier V in the filtration treatment zone N and the aerobic treatment zone M is appropriately mixed to be in a mixed state, and the aeration stirring by the diffusion tube 32 is performed again in the aerobic treatment zone N. The filtration process in the filtration process zone N is performed. Therefore, by repeating aeration and stirring by the backwash pipe 34, the carrier V in the filtration treatment zone N and the aerobic treatment zone M is appropriately switched up and down, thereby exchanging the role of the treatment function for the fluidized bed carrier V. This prevents the carrier V from being blocked in the biological filtration tank C, and effectively prevents anaerobic formation of the filtration treatment zone N.

  The secondary treated water that has flowed down to the bottom chamber 33 of the biological filtration tank C flows into the treated water tank D after flowing through the latent flow port 36 with the next treated water tank D, and the supernatant liquid is passed through the disinfection tank E. It discharges from the discharge pipe 2 after disinfecting.

It is a vertical side view of a sewage septic tank. It is a top view of a sewage septic tank. It is a partially cutaway perspective view showing an anaerobic contact tank. It is a perspective view which shows the advection chamber provided in the 3rd separation chamber of the baffle wall separation tank. It is a cross-sectional view which shows a biological filtration tank. It is a perspective view which shows the internal structure of a biological filtration tank. It is the top view which made the anaerobic contact tank into other embodiment. FIG. 8 is a longitudinal side view of FIG. 7, but the second baffle wall in the baffle wall separation tank is not configured to correspond to the scum baffle wall on the upper side from the advection port, and is located on the lower side from the middle part of the tank. The case where the underwater part is divided by the sludge blocking wall is illustrated.

Explanation of symbols

T Wastewater purification tank A Anaerobic contact tank A1 Contact chamber A2 Advection chamber B Block wall separation tank B1 First separation chamber B2 Second separation chamber B3 Third separation chamber C Biofiltration tank D Treated water tank E Disinfection tank X Anaerobic sludge Y Sludge floc Z Scum O Sediment sludge V Fluidized bed carrier M Aerobic treatment zone N Filtration zone 1 Inflow pipe 2 Outflow pipe 3 First baffle wall 4 Second baffle wall 3A, 4A Scum baffle wall 3B, 4B Sludge baffle wall 5 Main body front walls 6, 24 Overflow partition 7 Side wall 8 Inclined bottom wall 9 Inlet guide tube 10 Outlet 11 Rectifier plates 12, 22, 35 Submerged partition walls 13, 27, 36 Submerged ports 14, 18, 20 Advection port 15 Fumarole tube 16 Air supply pipes 17 and 28 Overflow ports 19 and 21 Communication port 23 Advection chamber 25 Back tilt 26 Forward tilt 30 Upper perforated plate 31 Lower perforated plate 32 Air diffuser tube 33 Bottom chamber 34 Backwash tube 37 Return air lift tube 38, 41 Inlet 39 Sewage Return Pipe 4 0 Air lift pipe for circulation 42 Circulation return pipe

Claims (2)

A sewage purification tank comprising a biological filtration tank filled with a fluidized bed carrier, and a baffle wall separation tank provided upstream of the biological filtration tank,
The baffle wall separation tank is defined by a first baffle wall, a second baffle wall provided downstream of the first baffle wall, and the first baffle wall and the second baffle wall. A separation chamber, a scum baffle wall formed on the upper side of the baffle wall in each of the first baffle wall and the second baffle wall, and a sludge baffle formed on the lower side of the baffle wall Having an advection opening formed between the wall and the scum barrier wall and the sludge barrier wall;
The scum baffle wall is configured to prevent scum accumulated in a floating state in the treated water upstream of the scum baffle wall from flowing out to the downstream side of the scum baffle wall,
The sludge baffle wall is configured to prevent sludge flocs and accumulated sludge contained in the treated water upstream of the sludge baffle wall from flowing out to the downstream side of the sludge baffle wall,
The advection port in the first baffle wall and the advection port in the second baffle wall are formed at the same height, thereby allowing the treated water to advancing horizontally in the separation chamber. A sewage septic tank. The sewage septic tank according to claim 1,
The baffle wall separation tank includes a latent flow partition that divides a downstream region of the second baffle wall in a plane U shape, a latent flow port formed at a lower end portion of the latent flow partition, and a rear side of the latent flow partition. An overflow port formed between the formed advection chamber and the biological filtration tank;
The treated water that advancing in the horizontal direction in the separation chamber and flowing out from the advection port of the second baffle wall to the downstream region of the second baffle wall flows into the advection chamber from the submergence port and flows into the advection chamber. The sewage septic tank is configured to overflow from the overflow port to the biological filtration tank after once rising.