JP6652898B2 - Water treatment device and water treatment method - Google Patents

Description

  The present invention relates to a water treatment apparatus and a water treatment method, and more particularly, to a water treatment apparatus and a water treatment method for treating organic wastewater discharged from sewage and food factories using a trickling filter type water treatment apparatus.

  The trickling filter type water treatment technology has the characteristics that it does not require aeration as compared with the standard activated sludge method, so that it consumes less power, generates less sludge, and can reduce the disposal cost of excess sludge. Therefore, in recent years, application to sewage treatment and the like in developing countries such as Southeast Asia where infrastructure such as electricity has not been developed has been studied.

  On the other hand, in the water treatment technology of the trickling filter type, since sludge adheres to the filter medium of the trickling filter bed, the attached sludge rots, resulting in a bad smell. It is known that a kind of Drosophila, called soybean, occurs. There is a problem that the working environment when performing maintenance is deteriorated due to the generation of such bad smells and filter flies.

  For example, Patent Document 1 (Japanese Patent Application Laid-Open No. 58-34088) discloses a method of contacting an alkaline solution with a trickling filter to wash the inside of the trickling filter in order to suppress the generation of offensive odor and filter flies. Has been described.

  Patent Literature 2 (International Publication No. 12/161339) describes a technique in which a sewage treatment system including a solid-liquid separation device and a sprinkling filter bed is provided with a washing means for washing a filter medium packed layer in the sprinkling filter bed. ing.

  Patent Literature 3 (Japanese Patent Application Laid-Open No. 2015-33666) includes a water trickling filter provided with a washing means and a biological treatment tank, and the water trickling filter is heated by warming the water trickling bed in the biological treatment tank. Techniques for heating the floor are described. Non-Patent Document 1 describes that a sprinkling filter section is periodically cleaned in a sprinkling filter type nitrification and denitrification reactor.

JP-A-58-34088 International Publication No. 12/161339 JP 2015-33666 A

“Effects of Psychodidae Generation Suppression by Sprinkling Filter Method by Filter Filter Cleaning”, Proceedings of Annual Meeting of Japan Society on Water Environment 2016, p68

  However, in the technique of Patent Literature 1, a chemical solution is costly due to the addition of a chemical, and the filter bed in the apparatus may be deteriorated by the addition of the chemical. The techniques of Patent Documents 2 and 3 and Non-Patent Documents all wash the trickling filter bed by flooding the trickling filter bed, but other water treatment connected to the trickling filter bed at the time of washing the trickling filter bed. It is necessary to partially stop the operation of the device, and the work efficiency is reduced. Furthermore, in the techniques of Patent Literatures 2 and 3 and Non-Patent Literature 1, a high turbidity cleaning wastewater is generated by submerging and washing the trickling filter bed, and this cleaning wastewater must be separately purified. There is also.

  The present invention has been made in view of the above problems, and provides a water treatment apparatus and a water treatment method that can efficiently suppress the generation of offensive odor and filter bed flies without stopping the operation of the water treatment apparatus.

  In order to achieve the above object, the present inventors have conducted intensive studies. As a result, at least two reaction tanks having both functions of a sprinkling filter type apparatus and a submerged filter type apparatus are connected, and a flow path of raw water supplied to these is connected. It is found that it is effective to switch at a predetermined timing.

  In one aspect, the present invention, which has been completed on the basis of the above findings, includes a first tank provided with a first carrier layer to which microorganisms are attached, and a second carrier layer connected to a subsequent stage of the first tank and to which microorganisms are attached. A second tank provided, a raw water supply path capable of supplying raw water to the first tank or the second tank, and switching means for switching the supply of raw water between the first tank and the second tank. By switching the supply of raw water to the first tank, the first tank treats the raw water by the immersion filter method in which the first carrier layer is immersed in the raw water and biologically treated, and the second tank is obtained in the first tank. The treated water is treated by a sprinkling filter method in which the treated water is sprayed from above the second carrier layer to biologically treat the treated water, and the switching means switches the supply of the raw water to the second tank. Raw water is treated by the immersion filter method in which the second carrier layer is immersed in water and biologically treated, and the first tank is the second tank Water treatment apparatus the treated water obtained by dispersing from the top of the first carrier layer processing the treated water by trickling filter method of biological treatment is provided.

  In one embodiment, the water treatment apparatus according to the present invention includes control means for controlling the switching operation by the switching means based on the degree of contamination of the tank to be treated by the trickling filter method.

  In another embodiment, the water treatment apparatus according to the present invention includes a screen disposed at a treated water outlet of the first tank and the second tank, and the control unit sprays water based on an amount of solids captured on the screen. This includes determining the degree of contamination of the tank to be treated by the filter bed method.

  In still another embodiment of the water treatment apparatus according to the present invention, the control means is treated by a trickling filter method on the basis of the amount of biomass attached to the first carrier layer or the second carrier layer. Determining the degree of contamination of the side tank.

  According to another aspect of the present invention, there is provided an immersion filter tank for immersing a first carrier layer to which microorganisms are attached in raw water for biological treatment, and a second carrier layer having microorganisms attached thereto. Treated water is sprayed from the upper part of the second carrier layer and sprayed and contacted by biological treatment, and a raw water supply path for supplying raw water to the immersion filter tank or the water filter bed tank, Switching means for switching the supply of raw water to the immersion filter tank side or the sprinkling filter tank side, and the switching means switches the supply of the raw water from the immersion filter tank side to the sprinkling filter tank side to thereby sprinkle water. Inject raw water into the filter bed tank, fill the inside of the sprinkler filter tank with raw water to wash the sprinkler filter tank, and supply the washing water of the sprinkler filter tank to the immersion filter tank side for biological treatment. A water treatment apparatus is provided.

  In another aspect of the present invention, raw water is supplied to a first tank provided with a first carrier layer to which microorganisms are attached, and the first carrier layer is immersed in the raw water in the first tank to perform biological treatment. In the second tank provided with the second carrier layer attached to the microorganisms and connected to the subsequent stage of the first tank while treating the raw water by the bed method, the treated water obtained in the first tank is used as the second carrier layer. Treating the treated water by a sprinkling filter method of spraying from the upper part and biologically treating, switching the raw water to be supplied from the first tank to the second tank, and providing the second carrier in the raw water in the second tank. Raw water is treated by the immersion filter bed method in which the layer is immersed for biological treatment, and in the first tank, the treated water obtained in the second tank is sprayed from the upper part of the first carrier layer to perform biological treatment. A water treatment method is provided that includes treating by a bed method.

  ADVANTAGE OF THE INVENTION According to this invention, the water treatment apparatus and water treatment method which can suppress generation | occurrence | production of a bad smell and a filter bed fly efficiently without stopping operation | movement of a water treatment apparatus can be provided.

It is a schematic diagram showing an example of a water treatment device concerning an embodiment of the invention. FIG. 2 is a schematic diagram illustrating an example of water treatment in a case where a treatment by a dipping filter method is applied to a first tank and a treatment by a sprinkling filter method is applied to a second tank in the water treatment apparatus shown in FIG. 1. FIG. 2 is a schematic diagram illustrating an example of water treatment in a case where a treatment by a trickling filter method is applied to a first tank and a treatment by a dipping filter method is applied to a second tank in the water treatment apparatus shown in FIG. 1. It is the schematic which shows an example of the water treatment apparatus which concerns on the modification of the water treatment apparatus shown in FIG. It is the schematic which shows an example of the water treatment apparatus which concerns on the modification of embodiment of this invention, applying the process by the immersion filter method to a 1st tank and a 3rd tank, and watering a 2nd tank and a 4th tank. It is a schematic diagram showing the example of the water treatment at the time of applying the treatment by the filter bed method. It is the schematic which shows an example of the water treatment apparatus which concerns on the modification of embodiment of this invention, applying the process by the trickling filter method to a 1st tank and a 3rd tank, and immersing in a 2nd tank and a 4th tank. It is a schematic diagram showing the example of the water treatment at the time of applying the treatment by the filter bed method. It is the schematic which shows an example of the water treatment apparatus which concerns on another modification of embodiment of this invention, and applies the sprinkling filter method to a 1st tank, and the immersion filter method of an upward flow to a 2nd tank. FIG. It is the schematic which shows an example of the water treatment apparatus which concerns on another modification of embodiment of this invention, When the upflow immersion filter method is applied to a 1st tank, and the sprinkling filter method is applied to a 2nd tank. FIG. 1 is a schematic diagram illustrating an example of a water treatment system incorporating a water treatment device according to an embodiment of the present invention. It is a schematic diagram showing the example of the water treatment system at the time of incorporating the water treatment device concerning an embodiment of the invention into existing water treatment equipment. It is a graph showing the relationship between transition of BOD volume load at the time of device start-up of the water treatment device according to the example and the comparative example and the elapsed days.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The embodiments described below exemplify an apparatus and a method for embodying the technical idea of the present invention. The technical idea of the present invention specifies the structure, arrangement, and the like of the components as follows. It does not do.

  As shown in FIG. 1, the water treatment apparatus according to the embodiment of the present invention includes a first tank 3 having a first carrier layer 31 having microorganisms attached thereto and a second tank having a second carrier layer 41 having microorganisms attached thereto. Switching means 5 for switching between the two tanks 4, the raw water supply paths 12a and 12b capable of supplying raw water to the first tank 3 or the second tank 4, and the supply of raw water between the first tank 3 and the second tank 4. And

  A raw water tank 1 for storing raw water is disposed in front of the first tank 3. A second tank 4 is connected to the subsequent stage of the first tank 3 via a pipe 13. A processing water tank 7 for storing the processing liquid in the second tank 4 via a pipe 14 is disposed downstream of the second tank 4.

  The first tank 3 and the second tank 4 may be reaction tanks that have both the functions of the trickling filter apparatus and the immersion filter apparatus. Specifically, the first tank 3 and the second tank 4 each have a filter bed formed by filling a carrier therein, and can spray a fluid to be treated (treatment fluid) from above the filter bed. The reaction tank is not particularly limited as long as it is a type of reaction tank capable of flooding the filter bed for a certain period. The first tank 3 and the second tank 4 may have the same shape or different shapes.

  As a material of the carrier constituting the first carrier layer 31 and the second carrier layer 41, any material may be used as long as microorganisms adhere thereto. For example, plastic, crushed stone and the like are suitably used. The shape of the carrier may be any shape such as a plate, a sphere, an ellipsoidal sphere, a column, a rectangular parallelepiped, a hollow, and a tube.

  The specific configuration for spraying the processing fluid onto the first carrier layer 31 and the second carrier layer 41 from above the first tank 3 and the second tank 4 is not particularly limited. That is, watering may be performed in any form as long as the treatment fluid is sprayed on the entire filter bed, and may be any of a perforated plate, a sprinkler type or a spiral type nozzle, and a self-propelled rotary watering machine. As the pipe 13 connecting the first tank 3 and the second tank 4, for example, a siphon or the like is employed so that the processing fluid flowing between the first tank 3 and the second tank 4 can flow with little power. it can.

  When one of the first and second tanks 3 and 4 functions as a “watering filter tank”, the other tank functions as a “flooding filter tank”. That is, as shown in FIG. 2, when the raw water is supplied to the first tank 3 via the pump 11, the switching means 5, and the raw water supply path 12a, the first tank 3 Function as a "immersion filter tank" for treating raw water by the immersion filter method in which the carrier layer 31 is immersed and biologically treated, and the second tank 4 uses the treated water obtained in the first tank 3 for the second treatment. It functions as a "watering filter tank" which treats treated water by the watering filter method of spraying from the upper part of the carrier layer 41 and biologically treating it.

  In FIG. 2, part of the treated water flowing out of the second tank 4 may be withdrawn by the pump 17 and circulated from the pipe 13 to the second tank 4 through the pipes 14, 15 a, 15 b and 15 c.

  On the other hand, as shown in FIG. 3, when the raw water is supplied to the second tank 4 via the pump 11, the switching means 5, and the raw water supply path 12b, the second tank 4 Functions as an “immersion filter tank” for treating raw water by the immersion filter method in which the carrier layer 41 is immersed and biologically treated, and the first tank 3 converts the treated water obtained in the second tank 4 into the first tank. Function as a "water sprinkling filter tank" for treating treated water by the sprinkling filter method of spraying from the upper part of the carrier layer 31 and biologically treating the treated water.

  In FIG. 3, a part of the treated water flowing out of the first tank 3 may be withdrawn by the pump 17 and circulated from the pipe 13 to the first tank 3 through the pipes 16a, 16b and 15c. The remaining treated water is sent to the treated water tank 7 through the pipes 16a, 16c, 15a, and 14.

  In the present embodiment, the “immersion filtration method (immersion filtration tank)” refers to immersing a carrier in a treatment fluid (raw water) and bringing the treatment fluid into contact with the treatment fluid from above or below the vessel. It means a method (apparatus) for biologically treating a treatment fluid by contacting the biofilm with the treatment fluid after attaching the biofilm to the surface.

  When the treatment fluid is treated by the immersion filter bed method, it can be operated as an anaerobic fixed bed without blowing air, or can be operated as an aerobic fixed bed by blowing air with a blower or the like. It is also possible to switch between anaerobic and aerobic by switching the blower installed in the immersion filter tank with a timer. As shown in FIGS. 5 and 6, when there are two or more immersion filter tanks, some tanks can be operated as an anaerobic fixed bed and the remaining tanks can be operated as an aerobic fixed bed. The flow direction of the processing fluid may be any of an upward flow and a downward flow. However, considering the combination with the sprinkling filter, the upward flow immersion filter is preferable.

When the immersion filter bed is of the aerobic type, removal of organic substances and nitrification can be promoted as compared with the anaerobic type. When aerating the immersion filter bed, it is preferable to control the amount of aeration air so that DO in the immersion filter bed becomes 0.5 mg / L or more. Since this aeration air volume is not an air washing (aeration for the purpose of washing the filter bed by the flow of the filter bed), a general aeration flow at the time of the air washing (50 to 60 m ³ / m ² / h (high-speed water supply) The amount of air to be aerated may be small compared to the amount of air during backwashing of filtration)), and the power required for aeration can be reduced.

  When the immersion filter bed is an anaerobic type, the denitrification reaction is promoted. In order to promote the denitrification reaction, organic matter and nitrate nitrogen are required, so that the treated water obtained in the sprinkling filter tank connected to the latter stage of the immersion filter tank can be circulated to the immersion filter tank side. preferable.

  The “watering filter method (watering filter tank)” in the present embodiment refers to a method in which a treatment fluid (raw water) is sprayed from the upper part of a filter bed and a biofilm is attached to a surface of a simple substance constituting the filter bed. Means a method (apparatus) for biologically treating a processing fluid by contacting the biological fluid with a processing fluid flowing downward from the top of the apparatus. By performing the trickling filter method for a long time, sludge adheres to the surface of the carrier layer constituting the filter bed, and the adhered sludge rots, thereby generating an odor. Alternatively, due to the sludge, a kind of butterfly fly called filter fly is generated.

  The switching means 5 includes a switching valve and the like, and is connected to a pipe 12a for supplying raw water to the first tank 3 and a pipe 12b for supplying raw water to the second tank 4, as shown in FIG. The switching means 5 can be electrically connected to the control means 6 and receives the control signal from the control means 6 to supply the raw water from the first tank 3 to the second tank 4 or the second tank 4. It is possible to switch from the tank 4 side to the first tank 3 side.

  The control means 6 is configured to control the switching operation (switching timing) by the switching means 5 based on the degree of contamination of the tank to be treated by the trickling filter method. When the degree of contamination in the trickling filter method satisfies a predetermined condition, the control means 6 switches the switching means 5 to switch the supply of raw water from the immersion filter tank to the trickle filter tank. This allows the raw water to flow into the sprinkling filter tank to fill the sprinkling filter tank with raw water and wash the sprinkling filter tank, and the washing water in the sprinkling filter tank is immersed in the filter tank. It can be supplied to the tank side for biological treatment. As a result, it is possible to efficiently suppress the generation of offensive odor and filter bed fly without stopping the operation of the water treatment apparatus. In addition, it is a matter of course that the operator may manually perform the switching by the switching unit 5.

  The timing of switching by the switching means 5 is not limited to the following, but can be based on, for example, the following indices.

(1) Amount of Solids Captured by Treated Water Screen As shown in FIG. 4, screens 32 and 42 each having a mesh width of about 0.5 to 2 mm are arranged at the processing outlets of the first tank 3 and the second tank 4. Since solids are captured on the screens 32 and 42 as the processing proceeds, if larvae, pupae, or adults of filter fly are observed in the captured solids, the screens are treated by the sprinkling filter method. It is determined that the degree of contamination of the tank on the other side is advanced, and the switching direction of the raw water supply is switched by the switching means 5. The confirmation of the solid matter captured on the screens 32 and 42 may be visually performed by the operator, or automatically performed by the control means 6 based on detection means such as a camera, and switched by the switching means 5. The operation may be controlled.

(2) Switching operation every certain period This is a method of periodically switching the operation every predetermined period based on the growth of filter fly, and it is preferable to switch the operation periodically in any period of 3 to 30 days. . The larvae of the filter fly grow on sludge (slime-like microbial clumps). The growth speed varies depending on the temperature and the like, but generally, the eggs become adults after 2 days of eggs, 9 to 15 days of larvae, and 2 to 4 days of pupae, and the survival period of adults is 4 to 14 days. Eggs hatch for three days, eggs attach to the filter bed and become adults, and since it takes about 30 days to lay eggs, switching to three days can prevent the eggs from hatching itself, If the eggs are attached after switching for 30 days, the eggs once grow to adults, but the eggs laid by the adults can be prevented from hatching.

(3) Amount of living organisms adhered to carrier This is a method of switching operation based on the amount of organisms adhered to the first carrier layer 31 or the second carrier layer 41. When the amount of organisms attached to the carrier (the amount of organisms attached to the carrier) is 3000 to 6000 mg-SS / L or more per the effective volume of the filled carrier, the amount of organisms attached to the carrier increases, the filter medium becomes blocked, and flies easily occur. Environment. Therefore, when the amount of organisms attached to the carrier becomes 3000 to 6000 mg-SS / L, the operator or the control means 6 determines that the degree of contamination of the tank to be treated by the trickling filter method is advanced, The switching of the supply of the raw water by the switching means 5 is performed.

  As a method for measuring the amount of organisms attached to the carrier, a predetermined amount of a filter medium (the number of pieces that can be separated one by one such as crushed stones, and a predetermined area if they cannot be separated like a filter cloth) are collected from a reaction tank, After removing the biofilm attached to the filter medium, the SS amount of the biofilm is measured. The biomass per effective volume of the reaction tank can be calculated from the amount of the carrier charged into the reaction tank and the SS amount of the biofilm attached to a predetermined amount of the filter medium.

  The measurement of the amount of organisms attached to the carrier is performed by sampling a part of the carrier at a predetermined timing, and a required period in which the amount of organisms attached to the carrier is 3000 to 6000 mg-SS / L or more is calculated. Switching by the switching means 5 may be performed.

  As described above, according to the water treatment apparatus and the water treatment method according to the embodiment of the present invention, the switching unit 5 switches the raw water supply paths 12a and 12b, which are the raw water inflow pipes, so that the operation of the apparatus can be performed for a long time. Without stopping, the watering filter can be flooded. Therefore, it is possible to prevent the generation of offensive odor and filter flies from the sprinkling filter for a long time, and the maintenance and management of the apparatus becomes easy. Also, compared to the conventional method of stopping the operation of the trickling filter bed and cleaning the filter bed, equipment such as pipes and pumps for washing and draining the trickling filter bed is not required, so that the cost and the installation area of the device are reduced. It also leads to reduction of Further, the washing wastewater generated at the time of washing the sprinkling filter bed can be continuously biologically treated in a later tank, so that it is not necessary to discharge the washing wastewater of high concentration.

(4) Modification As shown in FIGS. 5 and 6, similarly to the first tank 3 and the second tank 4, a reaction tank (third tank) having both functions of a trickling filter type apparatus and a submerged filter type apparatus. 8 and the fourth tank 9) can also be arranged in series. For example, as shown in FIG. 5, when the raw water is supplied to the first tank 3 via the pump 11, the switching means 5, and the raw water supply path 12a, the first tank 3 Functions as an "immersion filter tank" for treating raw water by the immersion filter method in which the carrier layer is immersed and biologically treated, and the second tank 4 uses the treated water obtained in the first tank 3 as a second carrier. The third tank 8 functions as a "watering filter tank" for treating the treated water by the sprinkling filter method of spraying from the upper part of the layer and biologically treating the treated water. The fourth tank 9 functions as a “immersion filter tank” for treating the treated water by the immersion filter bed method in which the carrier layer 81 is immersed and biologically treated, and the fourth tank 9 transfers the treated water obtained in the third tank 8 to the fourth tank 8. Function as a "water sprinkling filter tank" for treating the treated water by the sprinkling filter method of spraying from the upper part of the carrier layer 91 and biologically treating it.

  On the other hand, as shown in FIG. 6, when the raw water is supplied to the fourth tank 9 via the pump 11, the switching means 5, and the raw water supply path 12b, the fourth tank 9 Functions as an “immersion filter tank” in which raw water is treated by the immersion filter method in which the carrier layer 91 is immersed and biologically treated, and the third tank 8 converts the treated water obtained in the fourth tank 9 into the third tank. The second tank 4 functions as a "watering filter tank" for treating the treated water by the sprinkling filter method of spraying from the upper part of the carrier layer 81 and biologically treating the treated water. The first tank 3 functions as a “immersion filter tank” in which raw water is treated by the immersion filter method in which the second carrier layer is immersed and biologically treated. It functions as a "sprinkling filter tank" for treating treated water by the trickling filter method of spraying from the upper part of the carrier layer and biologically treating it. As described above, the number of reaction vessels can be increased in even units.

  As shown in FIG. 7 and FIG. 8, the dipping filter bed at the subsequent stage of the sprinkling filter tank is an upflow dipping filter bed so that the dipping filter bed has a function as a solid-liquid separation tank. Is also possible. Also in this case, similarly to the above-described embodiment, by switching the flow path by the control means 6, the filter bed can be immersed periodically to prevent the generation of filter bed flies. According to the apparatus shown in FIGS. 7 and 8, the SS component contained in the raw water and the biofilm separated from the filter bed are separated into solid and liquid on the immersion filter bed tank side. The sludge accumulated in the immersion filter bed is periodically pulled out to adjust the amount of sludge. This operation makes it possible to reduce the SS concentration in the treated water.

(5) Water Treatment System The water treatment apparatus according to the embodiment of the present invention can be incorporated in a water treatment system as shown in FIGS. 9 (a) to 9 (g). Screens, sedimentation basins, filtration devices, and the like are considered as the "pre-solid-liquid separation" device shown in FIGS. 9A to 9D, and are selected according to the amount and properties of the SS component contained in the raw water. The system shown in FIG. 9A is the simplest system. After removing impurities by solid-liquid separation in the first stage, the system is treated with the water treatment apparatus (the present apparatus) according to the embodiment of the present invention, and treated water is treated. Is released. As shown in FIG. 9 (b) and FIG. 9 (c), a solid-liquid separation device such as a final sedimentation basin or a biological filtration device is provided at the subsequent stage of the water treatment device according to the embodiment of the present invention, and SS in the treated water is provided. A system for separating components, as shown in FIG. 9 (d), may be a system in which an aeration tank and a solid-liquid separation tank are provided after the water treatment apparatus according to the embodiment of the present invention. Alternatively, as shown in FIG. 9 (e) to FIG. 9 (g), a UASB (Up-flow Anaerobic Sludge Blanket) is provided in front of the water treatment apparatus according to the embodiment of the present invention, and raw water is anaerobically prepared in advance. It is also suitably used for processing systems.

  The water treatment apparatus according to the embodiment of the present invention can also be used for existing water treatment systems in a facility-enhancing manner. For example, as shown in FIG. 10A, the treated water obtained in the existing first sedimentation basin is drawn into the water treatment apparatus according to the present embodiment, and the treated water is returned to the existing final sedimentation basin. it can. Alternatively, as shown in FIG. 10B, the treated water obtained in the existing first sedimentation basin may be drawn into the water treatment apparatus according to the present embodiment, and then returned to the aeration tank.

  As described above, the present invention is represented by the invention specifying matters appropriate in the claims based on the above disclosure, and can be modified and embodied in the execution stage without departing from the gist thereof.

  Hereinafter, Examples of the present invention are shown together with Comparative Examples, but these Examples are provided for better understanding of the present invention and its advantages, and are not intended to limit the invention.

(Example 1)
Water treatment was performed using the water treatment device shown in FIG. As raw water, artificial sewage (glucose 160 mg / L, peptone 160 mg / L, monopotassium phosphate 12 mg / L) was used. The components of the raw water were BOD 250 mg / L and CODCr 370 mg / L. The filter medium was filled with a carrier made of polypropylene in both the first tank and the second tank. The dimensions of the filled portion were L200 mm x D200 mm x H860 mm, and the capacity of the filter material filled portion was 34.4 L. After the excess sludge of the sewage treatment plant is brought into contact with the filter medium by circulation operation, the artificial sewage is used as raw water, and the load is increased stepwise in the range of 0.05 to 2.3 kg-BOD / m ³ / d of BOD volume load. The organism was made to acclimate to the filter medium by operating the filter medium (FIG. 11). After the adaptation, the operation was performed at a BOD volume load of 2.3 kg-BOD / m ³ / d. Part of the treated water was circulated such that the watering load in the watering filter tank became 40 m ³ / m ² / d. The sprinkling part of the sprinkling filter bed was sprinkled over the entire filter bed with a perforated plate.

  Table 1 shows the device operation status (switching status). In Example 1, the line was switched every week, and the watering filter tank and the immersion filter tank were switched. In Example 2, the line was switched every two weeks. In Example 3, the line was switched every month. The respective execution periods were set to four weeks, four weeks, and eight weeks for Examples 1 to 3, respectively. In the comparative example, in the water treatment apparatus shown in FIG. 1, the drainage, the carrier, and the operation load of the apparatus were the same as those in Example 1, but the line was not switched.

  Table 2 shows the occurrence of filter bed flies in Examples 1 to 3 and Comparative Example. As shown in Table 2, no filter flies were observed in Examples 1 and 2. In Example 3, the generation of filter bed flies was observed in the second tank during the sprinkling filter operation, but the occurrence of filter bed flies was not confirmed after the operation was switched. In the comparative example, on the 20th day of operation, the occurrence of filter fly was confirmed in the sprinkling filter section of the second tank, and the rear fly and its larva continued to develop until the 120th day after the experiment was completed.

DESCRIPTION OF SYMBOLS 1 ... Raw water tank 3 ... 1st tank 4 ... 2nd tank 5 ... Switching means 6 ... Control means 7 ... Treatment water tank 8 ... 3rd tank 9 ... 4th tank 11 ... Pump 12a ... Raw water supply path (piping)
12b: Raw water supply path (piping)
DESCRIPTION OF SYMBOLS 13 ... Pipe 14 ... Pipe 17 ... Pump 31 ... 1st carrier layer 32 ... Screen 41 ... 2nd carrier layer 42 ... Screen 81 ... 3rd carrier layer 91 ... 4th carrier layer

Claims (7)

A first tank having a first carrier layer to which microorganisms are attached;
A second tank connected to the subsequent stage of the first tank and including a second carrier layer to which microorganisms are attached;
A raw water supply passage capable of supplying raw water to the first tank or the second tank;
Supply of raw water, and a switching means for switching between said second vessel and said first vessel,
The switching means switches the supply of the raw water to the first tank, so that the first tank treats the raw water by an immersion filter method in which the first carrier layer is immersed in the raw water and biologically treated. Two tanks treat the treated water by a trickling filter method in which the treated water obtained in the first tank is sprayed from above the second carrier layer and subjected to biological treatment,
The switching means switches the supply of the raw water to the second tank, whereby the second tank treats the raw water by an immersion filter method in which the second carrier layer is immersed in the raw water and biologically treated. 1 tank treats the treated water by a sprinkling filter method in which treated water obtained in the second tank is sprayed from above the first carrier layer and subjected to biological treatment ,
A water treatment apparatus , wherein the switching means alternately switches between the first tank and the second tank based on the degree of contamination of the tank to be treated by the trickling filter method . The water treatment apparatus according to claim 1, wherein the switching unit switches the raw water every predetermined period in consideration of the growth of the filter fly. The said raw water supply path is connected below the said 1st tank and the said 2nd tank, and includes flowing raw water by an upward flow from under the said 1st tank or the said 2nd tank. A water treatment apparatus according to item 1. A screen disposed at a treated water outlet of the first tank and the second tank ;
Based on the captured solid content before Symbol screen, and control means for controlling said switching means,
Water treatment device according to claim 1 comprising a. The water treatment apparatus according to any one of claims 1 to 4 , further comprising a control unit that controls the switching unit based on a biomass of the carrier adhered to the first carrier layer or the second carrier layer. . An immersion filter tank for biological treatment by immersing the first carrier layer to which microorganisms are attached in raw water;
A sprinkling filter tank provided with a second carrier layer to which microorganisms are attached, and treated water from the immersion filter bed tank is subjected to biological treatment by spraying and contacting the water from the upper portion of the second carrier layer,
Raw water supply path for supplying raw water to the immersion filter tank or the sprinkling filter tank,
Switching means for alternately switching the supply of raw water to the immersion filter tank side or to the trickle filter tank side , based on the degree of contamination of the trickling filter tank,
The switching means switches the supply of raw water from the immersion filter tank to the sprinkle filter tank so that raw water flows into the sprinkler filter tank and fills the sprinkler filter tank with raw water. A water treatment apparatus for washing the sprinkling filter tank with the washing water and supplying the washing water of the sprinkling filter tank to the immersion filter tank side for biological treatment. Raw water is supplied to a first tank provided with a first carrier layer to which microorganisms are adhered, and the raw water is treated by the immersion filter bed method in which the first carrier layer is immersed in the raw water in the first tank and biologically treated. At the same time, in the second tank connected to the subsequent stage of the first tank and provided with the second carrier layer to which the microorganisms are attached, the treated water obtained in the first tank is sprayed from above the second carrier layer. Treating the treated water by a sprinkling filter method of biological treatment,
Switching to supply raw water from the first tank to the second tank;
The raw water is treated by the immersion filter method of immersing the second carrier layer in the raw water in the second tank and biologically treating the raw water, and in the first tank, the treated water obtained in the second tank is subjected to the treatment. Spraying from the upper part of the first carrier layer and treating by a trickling filter method for biological treatment ;
A water treatment method comprising: alternately switching between the first tank and the second tank based on the degree of contamination of the tank to be treated by the trickling filter method.

Images