JP2007000737A - Solid-liquid separator of combined sewer system and sewage treatment method effectively using existing treatment facility - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a construction term for installation and a cost, while using functions of an existing primary settling tank. <P>SOLUTION: This solid-liquid separator 20 is constructed by reconstructing the existing primary settling tank installed in a combined sewage treatment plant, and is provided with a filtering part 22 filtering treating object water 28 disposed in the upper layer area 11 of the primary settling tank, a thickening part 24 disposed in the lower layer area 12 of the primary settling tank, an opening/closing valve 44 with which the filtering part 22 communicates with the thickening part 24, or they are shut off, and a communication pipe 42 which makes drain from the filtering part 22 flow down to to the thickening 24 by gravity by opening the valve 44. The filtering part 22 is formed by juxtaposing a plurality of upper flow filtering tanks 26 having filtering medium layers 30 of floating filtering medium formed therein, and is provided with air jetting means 32 at the lower parts of the respective filtering medium layers 30. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a solid-liquid separation device and a sewage treatment method, and more particularly to a solid-liquid separation device and a sewage treatment method for a combined sewer that effectively uses an existing treatment facility.

  A combined sewage treatment plant is installed on the terminal side of the combined sewer where sewage and rainwater flow into the same pipe. As shown in FIG. 10, the combined sewage treatment plant generally includes a first sedimentation tank 1, a biological reaction tank 2, and a final sedimentation tank 3. First, in the settling basin 1, the suspended matter in the sewage 4 that has flowed in is settled and separated. In the biological reaction tank 2, organic components, nitrogen, and phosphorus in the sewage 5 are removed by biological treatment. In the final sedimentation basin 3, activated sludge is settled and separated from the treated water 6, and the supernatant water is discharged as treated water 7 into rivers and the sea.

  In this type of sewage treatment plant, the design amount of inflowing sewage is determined based on the time of fine weather, and regular treatment cannot be performed if a large amount of rainwater joins in rainy weather. Therefore, in many cases, the sewage exceeding the design water quantity is discharged through the settling basin 1 at first, or as a simple treatment with chlorination added thereto. However, since the initial sedimentation basin 1 is originally designed with a water area load based on the time of fine weather, it is impossible to perform sufficient sedimentation treatment even if sewage combined with a large amount of rainwater passes through the first sedimentation basin 1 And most of the fine suspended solids will accompany the discharged water. For this reason, in rainy weather, pollution of public water areas due to the discharge of sewage containing a large amount of pollutant that has been simply treated in a formal manner is regarded as a problem.

  Patent Document 1 discloses a sewage treatment method that employs a high-speed filtration tank as a measure for improving the problems of the combined sewage treatment plant. This high-speed filtration tank replaces the conventional first sedimentation basin, and is an upward flow type filtration tank filled with a floating filter medium. This high-speed filtration tank is capable of high-speed filtration with a filtration rate of 100 to 1000 m / day, and can ensure a water area load several to ten and several times that of the conventional first sedimentation basin. Therefore, the sewage treatment method described in Patent Document 1 is considered to be effective as a measure against rain in a combined sewage treatment plant.

Patent Document 2 also discloses an upward flow type filtration tank filled with a floating filter medium, and is considered to be effective as an alternative device for the first sedimentation basin in a combined sewage treatment plant.
JP 2003-136088 A Japanese Patent Laid-Open No. 7-289812

  However, when adopting the high-speed filtration tank described in Patent Document 1 or Patent Document 2 as a countermeasure against rain in an existing combined sewage treatment plant, it is necessary to secure a new site. When it is difficult to secure the site, it is necessary to newly install the high-speed filtration tank in the space where the existing first sedimentation basin has been removed. For this reason, installation of a high-speed filtration tank requires a great construction period and cost. It is conceivable to install a high-speed filtration tank using the body of the existing first sedimentation basin, but it is 50 steps and 50 steps as compared with the case of a new construction.

  The purpose of the present invention is to improve the problems of the prior art, and by making use of the function of the existing first sedimentation basin, by arranging a filtration section having a high filtration rate in the installation space of the first sedimentation basin, It is intended to provide a solid-liquid separation device and a sewage treatment method that are effective as a countermeasure against rain in an existing combined sewage treatment plant.

  In order to achieve the above object, a solid-liquid separation device for a combined sewer system that effectively uses an existing treatment facility according to the present invention was manufactured by modifying an existing first settling basin installed in a combined sewage treatment plant. A solid-liquid separator, a filtration unit arranged in the upper layer area of the first sedimentation basin and filtering water to be treated, a concentration unit arranged in a lower layer area of the first sedimentation basin, the filtration unit and the concentration unit, And an open / close means for communicating or blocking the water, and the open / close means is opened to allow the drainage from the filtration part to naturally flow down to the concentrating part.

  In the solid-liquid separation device according to the present invention, the first sedimentation basin is a two-layer sedimentation basin, and the space after removing the existing upper sludge scraping means installed in the upper layer area of the first sedimentation basin The filtration part is arranged in the above. In the solid-liquid separator having this configuration, it is desirable that the water surface of the concentrating unit is held higher than the bottom surface of the filtering unit.

  Further, in the solid-liquid separation device according to the present invention, the filtration unit is an upward flow type filtration unit in which a filter medium layer of a floating filter medium is formed, and air jetting means is provided below the filter medium layer. Features. The solid-liquid separation device having this configuration preferably includes a control unit that intermittently operates the air ejection unit and opens and closes the opening / closing unit in conjunction with the operation of the air ejection unit.

  Further, the combined sewer sewage treatment method that effectively utilizes the existing treatment facility according to the present invention is a merging of the treated water discharged from the filtration unit and the supernatant water discharged from the concentration unit of the solid-liquid separator having the above-described configuration. Water is supplied to a biological reaction tank disposed in the subsequent stage of the solid-liquid separator. In addition, when the amount of the combined water exceeds the allowable amount of the biological reaction tank, the excess combined water is discharged by bypass without flowing into the biological reaction tank.

  According to the solid-liquid separator according to the present invention, the water to be treated, which is sewage collected by the combined sewer, is first passed to the filtration unit disposed in the upper layer area of the settling basin, and the treated water after filtration is downstream. Sent to the bioreactor. Suspended matter trapped in the filtration unit can be entrained in the wastewater and allowed to flow naturally to the concentration unit disposed in the lower layer area of the first sedimentation basin through the communication unit. In the concentration unit, the suspended matter discharged from the filtration unit is allowed to settle, and the suspended suspended matter (sludge) can be discharged out of the apparatus.

  When an upward flow type filtration unit in which a filter medium layer of floating filter media is formed as the filtration unit, high-speed filtration with a filtration rate (water area load) increased to about 400 m / day is possible. Since the water area load of the existing first sedimentation basin is usually designed at 30 to 40 m / day, the solid-liquid separation device of the present invention can perform high-speed treatment about 10 times as compared with the normal first sedimentation basin. It is. Even when the first settling basin before remodeling is a two-level settling basin, the solid-liquid separation device of the present invention has a processing capacity at least about three times that of the two-level settling basin before remodeling. For this reason, even when the to-be-processed water which a lot of rainwater joined at the time of rain flows in into the said solid-liquid separator, a desired filtration function can be exhibited.

  In addition, the existing sedimentation basin can be partially remodeled, and the concentrating section can be constructed using the existing sedimentation basin structure as it is, so that the construction period and cost for remodeling can be minimized. That is, the solid-liquid separation device of the present invention has a function of the existing first sedimentation basin, and a filtration section having a high filtration rate is arranged in the installation space of the first sedimentation basin. It is effective for measures against rain in the existing combined sewage treatment plant.

  In addition, according to the sewage treatment method according to the present invention, high-speed filtration is possible in the filtration unit of the solid-liquid separator, which is effective as a measure against rain. In addition, the solid-liquid separation device has a structure in which a filtration section is arranged in the installation space of the first settling basin while making use of the function of the existing first settling basin, and the construction period and cost for remodeling can be saved.

  FIG. 1 is a side sectional view showing a first embodiment of a solid-liquid separation device according to the present invention, FIG. 2 is a view taken along the line AA in FIG. 1, and FIG. 3 is a plan view. This solid-liquid separator 20 is manufactured by modifying the existing first sedimentation tank 10 in the combined sewage treatment plant shown in FIG. The existing first sedimentation basin 10 is a two-level sedimentation basin composed of an upper layer area 11 and a lower layer area 12. The upper layer area 11 is equipped with a flight scraper type upper sludge scraper 13 and the lower layer area 12 is equipped with a flight scraper type lower sludge scraper 14. Suspended substances in the sewage flowing into each area settle and deposit on the bottom surfaces 11A and 12A of each area. The sludge accumulated on the bottom surfaces 11A and 12A is scraped to the sludge reservoir 15 side by the upper sludge scraper 13 and the lower sludge scraper 14, respectively. The sludge collected in the sludge reservoir 15 is discharged by the suction pump 16. The supernatant water of the upper layer area 11 is discharged from the overflow basin 17 and the supernatant water of the lower layer area 12 is discharged from the overflow basin 18 and sent to the biological reaction tank 2 shown in FIG.

  The solid-liquid separation device 20 according to the present invention shown in FIG. 1 has a filtration unit in the space after removing the upper sludge scraper 13 installed in the upper layer area 11 of the existing first sedimentation tank 10 shown in FIG. 22 is arranged. In addition, the lower layer area 12 is a concentration unit 24 in which the existing lower layer sludge scraper 14 is arranged as it is. The existing structures of the sludge reservoir 15 and the suction pump 16 are used as they are.

  A plurality of filtration tanks 26, 26,... In each filtration tank 26, a filter medium layer 30 of a floating filter medium having a specific gravity smaller than that of the water to be treated 28 is formed, and the water to be treated 28 is supplied to each filter tank 26 so as to flow upward with respect to the filter medium layer 30. The Below each filter medium layer 30, air ejection means 32 is provided, and compressed air 36 supplied from the blower 34 can be ejected from the air ejection means 32. An electromagnetic open / close valve 38 is attached to each pipeline that guides the compressed air 36, and the open / close valve 38 is opened / closed by an operation signal from the controller 40. One end of the communication pipe 42 is connected to the bottom of each filtration tank 26, and the other end of the communication pipe 42 opens into the concentration unit 24. Each communication pipe 42 is provided with an electromagnetic open / close valve 44, and these open / close valves 44 are also opened / closed by an operation signal from the controller 40.

  A screen 50 is disposed on the upper portion of the filtration tank 26 to prevent the floating filter medium from flowing out. That is, the floating filter medium that has floated due to the upward flow is restricted by the screen 50 from rising further, and the filter medium layer 30 having a fixed height with the screen 50 as the upper surface is stably formed.

  The treated water 28 flows from the inflow trough 46 to the lower part of the filtration tank 26 via the descending flow path 48 of each filtration tank 26 and then changes direction, and passes through the filter medium layer 30 as an upward flow. During this change of direction, suspended substances having a relatively large particle size in the water to be treated settle and deposit in the lower part of the filtration tank. Further, suspended substances having a relatively small particle diameter in the water to be treated 28 are captured by the floating filter medium in the process of passing through the filter medium layer 30. For this reason, most of the suspended solids are removed from the treated water 52 after passing through the filter medium layer 30, and the filtration tank 26 sufficiently exhibits the effect of the primary treatment. The treated water 52 is discharged from the solid-liquid separation device 20 via the outflow tank 54 and sent to a biological reaction tank or the like at the subsequent stage.

  FIG. 4 shows an example of the floating filter medium 60, where (1) is a side view and (2) is a front view. As a material, propylene having a specific gravity of less than 1 and excellent weather resistance is used. The basic shape is a mesh-like cylindrical body having a plurality of protrusions 62 inside. The diameter and height are 10 to 30 mm, the thickness of the wire forming the mesh is in the range of 2 to 4 mm, and the porosity is preferably 80% or more. The height of the filter medium layer 30 is preferably higher. However, in this embodiment, since the filtration tank 26 is installed using the upper layer area of the existing two-level sedimentation tank as described above, there are structural limitations. Therefore, the height of the filter medium layer 30 is designed to be 1 to 2 m.

  The smaller the filtration rate (upward flow rate) of the water to be treated 28 in the filtration tank 26, the higher the suspended matter removal rate in the filtration tank 26. Even if the filtration rate of the water to be treated 28 is increased to about 1000 m / day, the filter medium layer 30 exhibits the function of removing suspended substances. However, in order to perform an efficient and stable filtration operation, it is desirable to operate at a filtration rate of 400 m / day or less.

  As described above, suspended substances having a relatively large particle size in the water to be treated accumulate as sludge at the bottom of the filtration tank 26 in the course of the filtration operation. Sludge discharge operation is performed to discharge the sludge accumulated at the bottom. In this sludge discharging operation, first, the inflow of the water to be treated 28 is stopped. Next, the on-off valve 44 is opened. Then, the water to be treated in the lower part of the filtration tank 26 naturally flows as drainage to the concentration unit 24 side through the communication pipe 42, and sludge accumulated along the drainage at the bottom of the filtration tank 26 also enters the concentration unit 24 side. Transition.

  FIG. 5 is an explanatory view showing the state of the sludge discharge operation in the filtration tank 26. (1) shows an initial stage, and the sludge accumulated at the bottom of the filtration tank 26 is discharged by extracting the drainage from the communication pipe 42. Furthermore, since a downward flow is generated in the filter medium layer 30 and the floating filter medium of the filter medium layer 30 is in a weak flow state due to this downward flow, a part of the suspended matter trapped in the floating filter medium is partly. It moves away from the floating filter and is accompanied by the downward flow, and is accompanied by the drainage and moves to the concentration unit 24 side. This sludge discharging operation is performed until the level of the water to be treated in the filtration tank 26 reaches a predetermined position. (2) shows the final stage of the sludge discharging operation. The upper surface of the filter medium layer 30 coincides with the liquid level, and the filter medium layer 30 also descends as the liquid level decreases, and the upper surface leaves the screen 50. . At this final stage, the on-off valve 44 is closed to end the sludge discharge operation. Next, the flow returns to the filtration operation by restarting the inflow of the water to be treated 28 into the filtration tank 26. The sludge discharging operation is intermittently performed at a frequency of about once every 3 hours.

  When the filtration operation in the filtration unit 22 is continued for a long time, suspended substances gradually accumulate in the filter medium layer 30 of each filtration tank 26, and the filtration action is lowered. Therefore, a filter medium cleaning operation is performed. In this filter medium cleaning operation, first, the liquid level is lowered to the screen 50 and then air is blown out from the air blowing means 32.

  FIG. 6 is an explanatory diagram showing the state of the filter medium cleaning operation. A vortex is formed in the filtration tank 26 by the kinetic energy of the air ejected from the air ejection means 32. Due to this vortex flow, the floating filter medium 60 flows vigorously, and the suspended substances attached and deposited on the floating filter medium 60 are separated from the floating filter medium 60, and the suspended substances move to the liquid side. After the filter medium cleaning by the air ejection means 32 is performed for a predetermined time, the on-off valve 44 is opened while continuing the air ejection by the air ejection means, and almost all of the water to be treated including suspended substances in the lower part of the filtration tank 26 is discharged. It is allowed to flow down naturally as drainage to the concentrating part 24 side through the communication pipe 42. Next, after the on-off valve 44 is closed, the inflow of the water to be treated 28 is resumed and the liquid level is raised to the screen 50. Thereafter, the cleanliness of the floating filter medium 60 is updated by repeating the above-described filter medium cleaning as many times as necessary.

FIG. 7 is a time chart that shows a model of the sludge discharge operation and the filter medium cleaning operation described above. Each time the filtration operation a at time t ₁ is performed, the sludge discharge operation b at time t ₂ is repeated, and then the filter medium cleaning operation c at time t ₃ is performed. When the series of operations of a → b → a → b → a → b → a → c is set to one cycle and the time of one cycle is operated for 12 hours, filtration processing of two cycles per day is performed in the filtration unit 22. . In order to execute this series of operations in one cycle, it is necessary to switch the operation of the inflow and inflow stop of the water to be treated 28, the opening and closing of the on-off valve 44, and the ejection and stop of air from the air ejection means 32. The operation switching is controlled by an operation signal from the controller 40. The treated water inflow d, the opening e of the on-off valve 44, and the air ejection f shown in FIG. 7 generally show a series of operations in one cycle. The controller 40 executes these series of operations based on a predetermined time schedule.

  By the above-described sludge discharging operation and filter medium cleaning operation, waste water containing a large amount of suspended matter from the filtering unit 22 is discharged to the lower concentration unit 24. These suspended substances in the wastewater settle in the concentration section 24. Suspended matter (sludge) settled on the bottom surface of the concentration unit 24 is scraped to the sludge reservoir 15 side by the lower layer sludge scraper 14. The concentrated sludge collected in the sludge reservoir 15 is discharged out of the apparatus by the suction pump 16. The supernatant water 63 clarified by the sedimentation and separation of the suspended matter is discharged from the solid-liquid separation device 20 through the outflow trough 64, and is combined with the treated water 52 from the filtration unit 22 and sent to a biological reaction tank or the like at the subsequent stage. It is done.

  It is preferable to keep the water surface of the concentration unit 24 higher than the bottom surface of the filtration unit 22. The solid-liquid separation device 20 of the present embodiment has a filtration unit 22 installed using an upper layer area in an existing two-layer sedimentation basin, and in this case, an upper layer that separates the upper layer area and the lower layer area of the two-layer sedimentation basin. The bottom surface of the area is used as the bottom surface of the filtration unit 22. However, the bottom surface of the upper layer area is not originally designed to receive the load of the entire filtration unit 22. For this reason, in order to support the load of the filtration part 22 installed by remodeling, there exists a possibility that the bottom face intensity | strength of an upper layer area may be insufficient. If the water surface of the concentration unit 24 is kept higher than the bottom surface of the filtration unit 22 (that is, the bottom surface of the upper layer area), the buoyancy corresponding to the increased water head difference acts on the bottom surface of the filtration unit 22 to eliminate or alleviate the strength shortage. To do. Therefore, the reinforcement work for the bottom surface of the upper layer area can be unnecessary or minimized.

  According to the solid-liquid separator 20 of this embodiment, the to-be-processed water 28 which is the sewage collected by the combined sewer system is first passed through the filtration unit 22 disposed in the upper layer area of the settling basin, and processed after filtration. Water 52 is sent to the biological reaction tank in the subsequent stage. Suspended substances captured by the filtration unit 22 can be naturally flowed to the concentration unit 24 disposed in the lower layer area of the settling basin through the communication pipe 42 along with the drainage. In the concentration unit 24, the suspended matter discharged from the filtering unit 22 is settled, and the settled suspended matter (sludge) is scraped to the existing sludge reservoir 15 side by the existing lower layer sludge scraper 14. The concentrated sludge collected in the sludge reservoir 15 is discharged out of the apparatus by the existing suction pump 16.

  The filtration unit 22 is an upward flow type filtration unit in which the filter medium layer 30 of the floating filter medium 60 is formed, and high-speed filtration with a filtration rate (water area load) increased to about 400 m / day as described above is possible. is there. Since the water area load of the existing first sedimentation basin is normally designed at 30 to 40 m / day, the solid-liquid separation device 20 of the present embodiment is about 10 times faster than the normal first sedimentation basin. Is possible. Even considering that the first sedimentation basin before remodeling is a two-layer sedimentation basin and the site efficiency is higher than that of a single-layer sedimentation basin, the solid-liquid separation device 20 of this embodiment has a two-layer sedimentation before modification. Compared to ponds, it has at least 3 times the processing capacity. For this reason, even when the to-be-processed water 28 which a lot of rainwater merged at the time of rain flows into the said solid-liquid separation apparatus 20, a desired filtration function can be exhibited.

  In addition, the existing two-level sedimentation basin is partially remodeled, and the enrichment unit 24 is a structure that uses the existing sedimentation basin structure as it is, so that the construction period and cost for modification can be minimized. . That is, since the solid-liquid separation device 20 of the present embodiment makes use of the function of the existing first sedimentation basin, the filtration unit 22 having a high filtration rate is disposed in the installation space of the first sedimentation basin. It saves time and cost, and is effective for measures against rain in existing combined sewage treatment plants.

  FIG. 8 is a side sectional view showing a second embodiment of the solid-liquid separation device according to the present invention. In FIG. 8, elements denoted by the same reference numerals as those in FIG. 1 have the same functions as those described in the first embodiment, and the description thereof is omitted. The second embodiment has a structure in which an upper filtration section 22 composed of a plurality of filtration tanks 26 is added to the upper part of an existing single-layer first sedimentation basin. The existing single-layer first sedimentation basin is used as it is as the lower concentration section 24. The configuration of the communication pipe 42 provided with the on-off valve is the same as that of the first embodiment. The solid-liquid separation device of the second embodiment is suitable for the case where the existing first sedimentation basin is a single layer type.

  FIG. 9 is a system diagram showing an embodiment of the sewage treatment method according to the present invention. The solid-liquid separation device 70 is a device manufactured by modifying an existing first sedimentation basin, and includes a filtration unit 72 that is disposed in the upper layer area and filters the treated water 78, and a concentration unit 74 that is disposed in the lower layer area. In addition, an opening / closing means for communicating or blocking the filtering section 72 and the concentrating section 74 is provided, and a communicating section 76 for allowing the drainage from the filtering section 72 to naturally flow down to the concentrating section 74 by opening the opening / closing means. The treated water 78 collected by the combined sewer system is filtered by the filtration unit 72 of the solid-liquid separator 70 to be treated water 80. The suspended substance in the water to be treated 78 removed by the filtration unit 72 is transferred to the concentration unit 74 from the communication unit 76 along with the drainage of the filtration unit 72 and is subjected to a concentration process. The concentrated sludge 82 is discharged out of the system from the sludge reservoir 84 of the concentration unit 74. The supernatant water 86 of the concentrating unit 74 joins with the treated water 80 of the filtering unit 72 and is purified in the subsequent biological reaction tank 88. The treated water 90 in the biological reaction tank 88 is sent to the final sedimentation basin 92, and the sludge 94 is precipitated and separated. The supernatant water of the final sedimentation basin 92 is discharged as treated water 96.

  According to this sewage treatment method, high-speed filtration is possible in the filtration unit 72 of the solid-liquid separator 70, which is effective as a measure against rain. In addition, the solid-liquid separation device 70 has a structure in which the filtration unit 72 is arranged in the installation space of the first settling basin while making use of the function of the existing first settling basin, and the construction period and cost for modification can be reduced.

  In addition, since there is a limit in the filtration capability of the filtration part 72 of the solid-liquid separator 70, it sets and operates the upper limit of the filtration rate as 400 m / day, for example. Therefore, when the amount of treated water 78 flowing from the combined sewer system exceeds the filtration capacity of the filtration unit 72 during heavy rain, the excess treated water 98 is discharged by bypass as an emergency measure. The biological reaction tank 88 also has a limited processing capacity. Therefore, when the amount of combined water in which the treated water 80 of the filtration unit 72 and the supernatant water 86 of the concentrating unit 74 merge exceeds the allowable amount of acceptance in the biological reaction tank 88, the excess combined water 100 In the same way. However, the excess combined water 100 is correspondingly purified by the filtration process in the solid-liquid separator 70 in the previous stage. For this reason, it is possible to minimize contamination of public water areas due to bypass discharge.

It is a sectional side view showing a 1st embodiment of a solid-liquid separation device concerning the present invention. It is an AA arrow line view of FIG. It is a top view of a 1st embodiment. An example of a floating filter medium is shown, (1) is a side view and (2) is a plan view. It is explanatory drawing which showed the sludge discharge | release operation condition in the filtration tank 26, (1) shows an initial stage, (2) shows the last stage. It is explanatory drawing which shows the condition of filter medium washing | cleaning operation. It is the time chart which modeled and showed the situation of sludge discharge operation and filter media washing operation. It is a sectional side view which shows 2nd Embodiment of the solid-liquid separator which concerns on this invention. It is an apparatus system diagram showing an embodiment of a sewage treatment method according to the present invention. It is an apparatus system diagram of a combined sewage treatment plant according to the prior art. It is a sectional side view of the existing two-tiered sedimentation basin which concerns on a prior art.

Explanation of symbols

  10 …… First sedimentation basin, 11 …… Upper area, 12 …… Lower area, 13 …… Upper sludge scraper, 14 …… Lower sludge scraper, 15 …… Sludge reservoir, 16 …… Suction pump, 20 …… Solid-liquid separator, 22 …… Filtering section, 24 …… Concentration section, 26 …… Filter tank, 28 …… Water to be treated, 30 …… Filter medium layer, 32 …… Air ejecting means, 34 …… Blower, 36 .... Compressed air, 38 ... Open / close valve, 40 ... Controller, 42 ... Communication pipe, 44 ... Open / close valve, 46 ... Inlet, 48 ... Down flow path, 50 ... Screen, 52 ... ... treated water, 54 ... spillage, 60 ... floating filter, 63 ... supernatant water, 64 ... spillage, 70 ... solid-liquid separator, 72 ... filtration part, 74 ... concentration part, 76 ... ... communication part, 78 ... treated water, 80 ... treated water, 82 ... sludge, 86 ... supernatant water, 88 ... biological reactor 92 ...... final sedimentation pond, 96 ...... treated water.

Claims (7)

  A solid-liquid separation device manufactured by remodeling an existing first settling basin installed in a combined sewage treatment plant, the filtration unit being disposed in an upper layer area of the first settling basin, and filtering the treated water, A concentrating part arranged in the lower layer area of the settling basin, and a communication means for allowing the drainage from the filtering part to flow down to the concentrating part by opening and closing the opening / closing means for communicating or blocking the filtering part and the concentrating part. A solid-liquid separation device for a combined sewer system that effectively utilizes an existing processing facility.   The first sedimentation basin is a two-level sedimentation basin, and the filtration unit is disposed in a space after removing the existing upper sludge scraping means installed in the upper layer area of the first sedimentation basin. A solid-liquid separator for a combined sewer that effectively uses the existing processing facility according to claim 1.   The solid-liquid separation device for a combined sewer system utilizing the existing processing facility according to claim 2, wherein the water surface of the concentrating unit is held higher than the bottom surface of the filtering unit.   The said filtration part is an upward flow type filtration part in which the filter medium layer of the floating filter medium was formed, and was equipped with the air ejection means under the said filter medium layer, The Claim 1 or Claim 2 characterized by the above-mentioned. A solid-liquid separator for combined sewers that makes effective use of existing treatment facilities.   5. The existing processing facility according to claim 4, further comprising a control unit that operates the air ejection unit intermittently and opens and closes the opening / closing unit in conjunction with the operation of the air ejection unit. Used solid-liquid separator for combined sewerage.   The treated water discharged from the filtration unit of the solid-liquid separation device according to any one of claims 1 to 5 and the combined water of the supernatant water discharged from the concentration unit are disposed downstream of the solid-liquid separation device. A sewage treatment method for a combined sewer that effectively utilizes an existing treatment facility, which is supplied to a biological reaction tank disposed.   When the amount of the combined water exceeds the allowable amount of the biological reaction tank, the excess combined water is discharged by bypass without flowing into the biological reaction tank. Sewage treatment method for combined sewerage that effectively utilizes existing treatment facilities.

Images