JP2017042714A - Biological treatment apparatus and method for organic wastewater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a biological treatment apparatus for organic wastewater in which the construction is easy as well as a reduction in high place work and a space saving can be achieved.SOLUTION: Provided is an apparatus for biological treatment of organic wastewater in a biological treatment tank provided in multiple stages, and in which, in a first stage biological treatment tank 50, a first biological treatment water in which dispersed bacteria is increased by the decomposition of organic matter by the dispersed bacteria, is produced, and in a second biological treatment tank 60 in the later stage, the dispersed bacteria is subjected to predation by animalcule. The first biological treatment tank 50 and the second biological treatment tank 60 have tower bodies 10, 20 of the same shape and the same size, and the height of the tower body is 6 to 11 m, and the height to diameter ratio of the tower body is 1.5 to 5.0. The liquid in the second biological treatment tank 60 is circulated through a membrane separation tank 80, and permeated water is taken out from the membrane module 82 as treated water.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a biological treatment apparatus for organic wastewater that can be widely used for the treatment of organic wastewater such as domestic wastewater, sewage, food factories, pulp factories, semiconductor production wastewater, and liquid crystal production wastewater. The present invention relates to a biological treatment apparatus for organic wastewater provided with a biological treatment tower for biologically treating water. Moreover, this invention relates to the biological treatment method of the organic waste water using this processing apparatus.

The activated sludge method used when biologically treating organic wastewater is widely used for sewage treatment, industrial wastewater treatment, and the like because of its advantages such as good treated water quality and easy maintenance. However, since the BOD volumetric load in the activated sludge method is generally about 0.5 to 0.8 kg / m ³ / d, a large site area is required. Moreover, since 20 to 40% of the decomposed BOD is converted into microbial cells, that is, sludge, a large amount of excess sludge treatment is also a problem.

For high load treatment of organic waste water, a fluidized bed method with a carrier added is known. When this method is used, it is possible to operate with a BOD volume load of ³ kg / m ³ / d or more. However, this method has a disadvantage that the amount of generated sludge is about 30 to 50% of the decomposed BOD and is higher than that of the normal activated sludge method.

  In Patent Document 1, organic wastewater is first treated with bacteria in a first treatment tank, and organic matter contained in the wastewater is oxidatively decomposed and converted into non-aggregating bacterial cells, and then in a second treatment tank. It is described that excess sludge can be reduced by predatory removal of the sticking protozoa. Further, this method enables high-load operation and improves the processing efficiency of the activated sludge method.

  In this way, many wastewater treatment methods have been devised that use the predation of protozoa and metazoans located at high levels of bacteria. For example, Patent Document 2 describes a countermeasure against deterioration in processing performance due to fluctuations in the quality of raw water, which is a problem in the processing method of Patent Document 1. As specific methods, “adjust BOD fluctuation of treated water to within 50% from median average concentration”, “measure water quality in first treatment tank and first treated water over time”, The method includes “adding a microbial preparation or seed sludge to the first treatment tank when the quality of the first treated water deteriorates”.

  In Patent Document 3, flocs that are preyed by ultrasonic treatment or mechanical agitation when protozoa or metazoans prey on bacteria, yeast, actinomycetes, algae, molds, wastewater treatment primary sludge or surplus sludge. A method to make the flock size smaller than the animal's mouth is proposed.

  There exists a thing of patent document 4 as a biological treatment method of the organic waste_water | drain by the multistage process of a fluidized bed and an activated sludge process. In this method, the latter activated sludge method is operated at a low load of BOD sludge load 0.1 kg-BOD / kg-MLSS / d, so that the sludge can be self-oxidized and the amount of sludge extraction can be greatly reduced.

  As a tank body of a conventional biological treatment tank, a concrete water tank or a tower-like elevated water tank is used.

The concrete tank has the following problems.
(B) The tank body will be used for civil engineering work, and the tank internal equipment will be installed after the tank construction. Concerns remain in terms of construction and quality control.
(B) Since the water depth is practically up to about 4 m in practice, the installation space at the site becomes large.
(C) Even if it is desired to reinforce equipment in response to an increase in raw water load, it cannot be easily expanded due to local civil engineering work and large installation area.
(D) It is difficult to check for liquid leakage from the bottom.
(E) It is necessary to repair the tank inner lining.

The tower-shaped elevated tank has the following problems.
(F) In order to secure the capacity while suppressing the installation space, it is necessary to increase the tank height, and at least about 7 m is required. In this case, it is necessary to climb to the upper part of the tank during on-site piping construction and daily maintenance, and usually a staircase or a ladder is installed. For this reason, workability | operativity worsens.
(G) The burden of the transition piping work from the upper part of the tank in the field tends to increase.
(H) Depending on the tank material and liquid quality, it is necessary to repair the tank inner lining.

  A membrane separation activated sludge method is known in which organic wastewater is biologically treated and then separated into membranes (for example, Patent Document 5).

Japanese Patent Laid-Open No. 55-20649 JP 2000-210692 A Japanese Patent Publication No. 60-23832 Japanese Patent No. 3410699 JP 2012-206041 A

As described above, the conventional concrete tank or tower-shaped elevated tank has the following problems.
1) The installation area of the concrete tank is large.
2) The construction period will be longer in concrete tanks.
3) It is not easy to reinforce equipment in a concrete tank.
4) Tower-type water tanks with large tank heights have poor work efficiency due to work at high places, and it is necessary to improve workability and prevent falling accidents.
5) In tower-type water tanks with large tank heights, piping from the top of the tank to the outside will be generated, increasing the burden of on-site construction, so it is necessary to simplify on-site construction.

  An object of the present invention is to solve these problems, and to provide a biological treatment apparatus and treatment method for organic wastewater that is easy to construct and can reduce work at high places and save space. .

  It is another object of the present invention to provide an organic wastewater biological treatment apparatus and treatment method that can easily cope with various changes in raw water quality, required water quality, and increased amount of treated water.

  The organic wastewater biological treatment apparatus of the present invention is an apparatus for biologically treating organic wastewater in a biological treatment tank provided in multiple stages. In the first biological treatment tank, the organic wastewater is dispersed by decomposing organic matter by dispersal bacteria. The first biological treatment tank and the second biological treatment tank in the organic wastewater biological treatment apparatus for generating the second biological treatment water in the second biological treatment tank in the subsequent stage, generating the first biological treatment water in which the bacteria increased. Has a tower body of the same shape and size, the height of the tower body is 6 to 11 m, and has a membrane separation tank into which a biological treatment liquid is circulated and introduced from the biological treatment tank at the final stage. It is characterized by.

  In this invention, it is preferable that ratio (H / D) of the height (H) and diameter (D) of a tower body is 1.5-5.0. Moreover, in this invention, it is preferable that the installation height TOP (TOP of pipe) of a manhole and most, for example, half or more of pipe connection parts, is 3 m or less.

  In the present invention, it is preferable that each biological treatment tank is filled with a fluidized bed carrier, and a strainer for preventing the fluidized bed carrier outflow is provided in the treatment liquid outflow portion of the biological treatment tank other than the final stage.

  In the present invention, the membrane separation tank is provided with a separation membrane and an air diffuser in the tank, and the up-flow produced by the air diffused from the air diffuser causes the final stage biological treatment tank and the membrane separation tank to be separated from each other. You may comprise so that a biological treatment liquid may circulate between.

  In this invention, you may install two or more 1st biological treatment tanks and 2nd biological treatment tanks in parallel.

  In the present invention, the tower body is preferably made of FRP and is integrally formed as a whole from the tower bottom to the tower top. In this case, it is preferable that the thickness of the lower part of the tower body is larger than the thickness of the upper part of the tower body. Moreover, it is preferable that at least a part of the vertical piping has a half-cylindrical shape and is bonded to the inner peripheral surface of the tower body.

  The organic wastewater biological treatment method of the present invention uses the biological treatment apparatus of the present invention.

  The organic wastewater treatment apparatus of the present invention is provided with a plurality of water treatment units having towers of standard dimensions (same shape, same size), and each water treatment unit is manufactured in advance in a factory. I can leave.

  In the present invention, by using a separation membrane for solid-liquid separation of biologically treated water, the quality of the treated water can be kept good, and the sludge concentration in the biological treatment tank is kept high and high load treatment is performed. In addition, since a settling tank is not necessary, the apparatus can be made small.

  In particular, when the tower height of the biological treatment tank is large, the water depth becomes deep, the amount of dissolved air increases, the sedimentation method deteriorates the sedimentation property of sludge, and the sludge separation efficiency decreases, but the membrane separation method was adopted. As a result, the sludge can be prevented from flowing out and the quality of the treated water can be improved.

  In the present invention, since the sizes of the tanks are unified, the design and construction of the apparatus are also made common and can be performed easily and quickly. Moreover, the space between tanks can also be made small. Furthermore, it is easy to add a biological treatment tank.

  By constructing the tower body integrally with FRP, the weight is reduced, and transportation and installation work are also facilitated. In this case, the strength, pressure resistance, and durability of the tower can be increased by increasing the thickness of the lower part of the tower. In addition, by making the vertical piping into a half-cylindrical shape and adhering to the circumferential surface of the tower body, the structure inside the tower body can be simplified, and the water circulation flow inside the tower body can be made smooth. Also, the installation strength of the vertical piping is increased.

  In one embodiment of the present invention, the joint locations and manholes of most pipes are provided in the lower part of the tower (the height of the ground is 4 m or less), so the number of work at high places is small.

  In one embodiment of the present invention, biological treatment tanks are provided in multiple stages, the biological treatment tank in the previous stage is a dispersion bacteria tank that converts organic matter into dispersal bacteria, and the last biological treatment tank has an adhesive property that prey on the dispersal bacteria. A carrier is provided as a scaffold for filtered predatory microanimals. In this treatment, the micro-animal can be stably maintained, and the treated water quality can be stabilized.

It is a longitudinal cross-sectional view of the biological treatment apparatus of the organic waste_water | drain which concerns on embodiment. It is the II-II arrow directional view of FIG. It is a longitudinal cross-sectional view of the biological treatment apparatus of the organic waste_water | drain which concerns on another embodiment. (A) is the sectional view on the AA line of FIG. 3, (b) is the sectional view on the BB line of FIG. It is the VV sectional view taken on the line of FIG. It is VI-VI arrow line view of FIG. It is a top view which shows the example of water treatment unit arrangement | positioning in the biological treatment apparatus of the organic waste_water | drain of this invention.

  DESCRIPTION OF EMBODIMENTS Embodiments of an organic wastewater biological treatment apparatus and treatment method of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows an embodiment of a biological treatment apparatus for organic wastewater according to the present invention. A first biological treatment tank 1, a second biological treatment tank 2, and a membrane separation tank 30 stand on a foundation 3. It is installed. The first biological treatment tank 1 and the second biological treatment tank 2 are connected in series by a pipe 4. The second biological treatment tank 2 and the membrane separation tank 30 are configured such that biological treated water is circulated through the pipes 34 and 35.

  The first biological treatment tank 1 is connected to the cylindrical tower 10, the raw water inlet 11 a having a flange structure provided on the lower side surface of the tower 10, and the raw water inlet 11 a, The raw water introduction pipe 11 whose upper end is opened above the outlet 14 a, the air diffusion pipe 12 provided at the bottom of the tower body 10, and the upper side of the air diffusion pipe 12 in the tower body 10 The fixed bed or rocking bed carrier 13 installed in the upper part of the tower body 10 and the treated water outlet 14a provided at the upper part of the tower body 10 are provided. The air diffuser 12 is connected to a blower (not shown) as a gas supply device. Here, as the blower, when the water level is high, a high pressure blower having a capability of a discharge pressure of 60 kPa or more such as a screw blower or a turbo blower is preferable.

  The outflow pipe 14 is connected to the outflow port 14a. The outflow pipe 14 extends downward along the outer surface of the tower body 10, and the lower end is a pipe connection part 14b having a flange structure. As shown in FIG. 2, a crank-shaped bent portion 14c is provided in the middle of the outflow pipe 14 in the vertical direction.

  An opening 15 a is provided at the top of the tower body 10, and one end of the atmosphere communication pipe 15 is connected thereto. As shown in FIG. 2, the atmosphere communication pipe 15 extends downward on the outer surface of the tower body 10 along the tower body 10, and the lower end 15 b is opened downward in the immediate vicinity of the foundation 3. The upper end of the outflow pipe 14 communicates with the laterally extending portion 15b of the atmospheric communication pipe 15 through an inverted U-shaped communication pipe 14d.

  As shown in FIG. 2, a preliminary seat 16 is provided at the top of the tower body 10, and a manhole 17 and a preliminary seat 18 are provided at the lower portion.

  The second biological treatment tank 2 includes a cylindrical tower body 20 having the same shape and size as the tower body 10, a flanged structure inlet 21 provided on the lower side surface of the tower body 20, and the inside of the tower body 20. Are provided with an air diffuser 22 provided at the bottom and an outlet 23 provided on the side of the tower 20. In FIG. 2, although the outflow port 23 is provided in the upper part of the tower body 20, you may provide in the lower side than it. The inflow port 21 is connected to the pipe connection portion 14b through the pipe 4. The air diffuser 22 is connected to a blower (not shown). This blower is shared with a blower for supplying air to the air diffuser 12.

  An opening 25 a is provided at the top of the tower body 20, and one end of the atmosphere communication pipe 25 is connected thereto. The atmosphere communication pipe 25 extends downward along the tower body 20 on the outer surface of the tower body 20, and the lower end 25 b is opened downward in the immediate vicinity of the foundation 3.

  Although illustration is omitted, like the tower body 10, a preliminary seat is provided at the top of the tower body 20, and a manhole, a spare seat, and an air supply pipe to the diffuser pipe are provided at the lower part. A fluidized bed carrier 29 is packed in the tower body 20.

  The membrane separation tank 30 includes a tank body 31, a membrane module (separation membrane module) 32 provided in the tank body 31, and an air diffusion pipe 33 provided below the membrane module 32. Air is supplied to the air diffuser 33 from a blower common to the air diffusers 12 and 22.

  The inlet 35 at the lower part of the tank body 31 is connected to the outlet 23 of the second biological treatment tank 2 through a valve 35 a and a pipe 34.

  A lower end of a pipe 37 is connected to the outlet 36 at the top of the tank body 31 through a valve 36a. The pipe 37 rises upward along the second biological treatment tank 2. The upper part of the pipe 37 is drawn into the upper part of the second biological treatment tank 2 and opens downward toward the second biological treatment tank 2 above the water level of the second biological treatment tank 2.

  The membrane module 32 may be a system in which flat membranes and hollow fiber membranes are arranged in various shapes in the water tank, but a system in which the membrane surface is installed vertically is suitable. Examples of the type of membrane include MF membrane, UF membrane, and NF membrane. The membrane module 32 may be one that allows water to pass therethrough by water pressure, or may be one that sucks the secondary side of the membrane module 32 with a pump and allows water to pass therethrough.

  A treated water extraction pipe 38 is connected so as to communicate with the inside of the membrane module 32. The pipe 38 passes through the tank body 31 and is drawn out of the tank body 31. A valve 38 a is provided in the pipe 38.

  Connected to the upstream side of the valve 38 a of the pipe 38 is a pipe 40 for injecting a cleaning chemical such as backwash water or hypochlorous acid aqueous solution for cleaning the membrane module 32. The pipe 40 is provided with a valve 41.

  A pipe 39 for discharging settled sludge, membrane module washing waste water, and the like is connected to the lower part of the tank body 31. The pipe 39 is provided with a valve 39a. During normal water treatment operation, the valves 35a, 36a, and 38a are open, and the valves 39a and 41 are closed.

  The tower bodies 10 and 20 and the tank body 31 of the membrane separation tank 30 are preferably made of resin such as FRP in order to eliminate the need for lining, but may be a steel plate depending on the water quality. In the case of FRP, it is preferable to apply a weather-resistant paint (for example, a tank stainless coat made by Torch Co., Ltd.) for the purpose of preventing deterioration due to ultraviolet rays and improving corrosion resistance. Moreover, when the tower bodies 10 and 20 are made of FRP, it is preferable to make the thickness of the lower part of the tower body where the water pressure becomes larger than that of the upper part. The upper and lower parts of the tower body may be thicker than the upper part, and the lower part may be thicker than that.

  The first and second biological treatment tanks 1 and 2 are provided with an excess sludge take-out pipe, a drain pipe, an insertion pipe for a monitoring camera in the tank, a wiring insertion opening, a sampling opening (not shown), and the like. Monitoring in the tank is performed by always or appropriately inserting a camera or a photographing device (preferably with illumination or an infrared camera) having a moving image shooting function into the tank. Shooting data is transmitted wirelessly or by wire. The photographing data may be stored in the photographing equipment. A heat insulating material may be wound around the tower in advance.

  If necessary, measuring instruments such as a water level gauge, pressure gauge, flow meter, water temperature gauge, water quality meter, etc. are installed in the water tank or peripheral equipment, piping, etc., and used for monitoring the operation status, operating control, operation management, etc. In addition, it is used for optimizing the treatment in the water tank in combination with incidental facilities (for example, facilities equipped with water supply, heating, chemical injection, aeration, dehydration functions, etc.).

  In order to treat organic wastewater with this organic wastewater biological treatment device, raw water (organic wastewater) is introduced into the first biological treatment tank 1 through the introduction pipe 11 and aerated through the aeration pipe 12 to be dispersible. Bacteria (non-aggregating bacteria) oxidatively degrade 70% or more of organic components (soluble BOD), desirably 80% or more, and more desirably 85% or more. The pH of the first biological treatment tank 1 is preferably 6 to 8.5. However, when the raw water such as food manufacturing wastewater contains a lot of oil, or when the raw water such as semiconductor manufacturing wastewater or liquid crystal manufacturing wastewater contains a lot of organic solvent or cleaning agent, the pH is 8 It is good also as ~ 9.

The water flow to the 1st biological treatment tank 1 shall be a transient type. The BOD volumetric load of the first biological treatment tank 1 is 1 kg / m ³ / d or more, for example 1 to 20 kg / m ³ / d, HRT (raw water retention time) is 24 h or less, preferably 8 h or less, for example 0.5 to 8 h By doing so, it is possible to obtain treated water predominated by dispersible bacteria, and by shortening the HRT, wastewater having a low BOD concentration can be treated with a high load.

Returning a part of sludge from the subsequent biological treatment tank to the first biological treatment tank 1, making the first biological treatment tank 1 a multistage configuration of two or more tanks, or installing a carrier 13. Thus, high load processing with a BOD volumetric load of 5 kg / m ³ / d or more is also possible. A fluid bed carrier may be filled as the carrier.

  When the carrier 13 is a rocking bed carrier, the material is preferably a foamed synthetic resin, particularly a flexible polyurethane foam. When a porous sheet-like oscillating bed carrier such as a thin plate-like or strip-like lightweight polyurethane foam is installed in the first biological treatment tank 1, the oscillating bed carrier has sufficient elasticity, Even if it is thin, it has sufficient mechanical strength and does not break by being bent in the flow of water in the tank. Moreover, by bending, it mixes uniformly, without inhibiting the water flow in a tank, and a sludge containing liquid comes to flow uniformly also into the porous structure of a support | carrier.

  When the filling rate of the carrier in the first biological treatment tank 1 is high, dispersal bacteria are not generated, and bacteria adhere to the carrier or filamentous bacteria grow. Therefore, the filling rate of the carrier added to the first biological treatment tank 1 is 10% or less, for example 1 to 10% in the case of a fluidized bed carrier, and 5% or less in the case of a fixed bed carrier or a rocking carrier, for example, By setting the content to 0.5 to 5%, it is possible to produce dispersal bacteria that are not affected by concentration fluctuation and are easy to eat.

  The dissolved oxygen (DO) concentration in the first biological treatment tank 1 may be 1 mg / L or less, preferably 0.5 mg / L or less to suppress the growth of filamentous bacteria.

  The treated water (first biological treated water) in the first biological treatment tank 1 is introduced into the second biological treatment tank 2 in the subsequent stage through the outlet 14a, the pipes 14, 4 and the inlet 21, and aerated and remains. The amount of excess sludge is reduced by oxidative degradation of organic components, self-degradation of dispersible bacteria, and predation of minute animals.

  In the second biological treatment tank 2, it is necessary to use an operation condition and a treatment apparatus that allow the microanimal and the bacteria to remain in the system in order to use the action of the microanimal having a slower growth rate than the bacteria and the autolysis of the bacteria. . Therefore, in this embodiment, the second biological treatment tank 2 is filled with a fluidized bed carrier 29 to increase the amount of minute animals retained in the tank.

  The shape of the fluidized bed carrier 29 is arbitrary such as a spherical shape, a pellet shape, a hollow cylindrical shape, a thread shape, and a plate shape, and the size (diameter) is about 0.1 to 10 mm. The material of the carrier 29 is arbitrary such as a natural material, an inorganic material, or a polymer material, and a gel material may be used. The carrier is not limited to a fluidized bed carrier, and may be either a fixed bed carrier or a rocking carrier, and two or more kinds of carriers may be used in combination.

  In the second biological treatment tank 2, a large amount of scaffolding for maintaining micro-animals is required. However, if the filling rate of the carrier is excessively high, mixing in the tank, sludge decay, etc. may occur. The filling rate is preferably 0.5 to 50%, more preferably about 1 to 40%.

  In order to promote predation by the minute animals, the pH of the second biological treatment tank 2 may be 7.0 or less.

  In the second biological treatment tank 2, not only the filtration predation type micro-animal that prey on the dispersed cells, but also the aggregate predation type micro-animal that can prey on the flocked sludge grows. Since the latter prey on flocs while swimming, if priority is given, sludge is eaten and becomes sludge in which fine floc pieces are scattered (sludge with poor sedimentation). In addition, this floc piece causes clogging of the membrane particularly in the membrane activated sludge method in which membrane separation is performed in the latter stage. Therefore, in order to thin out the aggregate predatory microanimals, it is desirable to control the SRT to be constant within a range of 60 days or less, preferably 45 days or less. However, if it is less than 15 days, it is unnecessarily frequent, and the number of not only aggregate predation type micro-animals but also filtration predation type micro-animals is excessively reduced.

  In the first biological treatment tank 1, it is necessary to decompose most of the organic matter, that is, 70% or more of the wastewater BOD, desirably 80% or more, and convert it into microbial cells. When the organic substances are completely decomposed, flocs are not formed in the second biological treatment tank 2, and there is not enough nutrients for the growth of micro-animals. Only sludge with poor compaction (sludge with poor sedimentation) is excellent. It becomes an occupied biological treatment tank. Therefore, a part of the raw water is bypassed and supplied to the second biological treatment tank 2 so that the sludge load due to the soluble BOD in the second biological treatment tank 2 is 0.025 kg-BOD / kg-MLSS / d or more. You may drive. The MLSS at this time includes MLSS for the carrier adhering.

  The liquid in the second biological treatment tank 2 is introduced into the membrane separation tank 30 from the outlet 23 through the pipe 34 together with a part of the fluidized bed carrier 29. By performing air diffusion from the air diffusion pipe 33, an upward flow is generated in the membrane separation tank 30. In addition, an air lift action occurs in the pipe 37. Thereby, the liquid introduced into the membrane separation tank 30 rises in the tank 30 and is returned from the outlet 36 to the upper part of the second biological treatment tank 2 via the pipe 37. In this tank 30, part of the water passes through the membrane module 32 and is taken out from the pipe 38 as treated water.

  When the air diffused from the air diffuser 33 strikes the membrane module 32, the adhesion and accumulation of sludge on the membrane surface is prevented.

  When the membrane module 32 is clogged, the valves 35a, 36a, 38a are closed, the valves 41, 39a are opened, and a cleaning chemical such as backwash water or hypochlorous acid aqueous solution is supplied from the pipe 40 to the membrane module. The membrane module 32 is back-washed or chemical-cleaned. The cleaning waste liquid is discharged from the pipe 39. In the case of backwashing with water, the valve 39a may be closed and one or both of the valves 35a and 36a may be opened so that the backwash wastewater is not discharged from the pipe 39. As the backwash water, the permeated water of the membrane module 32 can be used.

  With reference to FIGS. 3-6, the biological treatment apparatus of the organic waste_water | drain which concerns on another embodiment of this invention is demonstrated. As shown in FIG. 3, in this organic wastewater biological treatment apparatus, a first biological treatment tank 50, a second biological treatment tank 60, and a membrane separation tank 80 are erected on a foundation 43. The first biological treatment tank 50 and the second biological treatment tank 60 are connected in series by a pipe 70. In addition, the biological treatment liquid in the second biological treatment tank 60 is circulated through the membrane separation tank 80 via the pipes 84 and 87.

  The first biological treatment tank 50 includes a cylindrical tower body 50a made of FRP, a raw water (treated water) inlet 51a having a flange structure provided on a lower side surface of the tower body 50a, and a continuous from the inlet 51a. The raw water introduction pipe 51, the diffuser pipe 52 provided at the bottom of the tower body 50 a, the air pipe 53 that connects the diffuser pipe 52 to a blower (not shown), and the siphon break pipe 53 A that is connected to the air pipe 53. A plurality of strainers 54, 54 provided in the middle of the vertical direction of the tower body 50 a or lower thereof, a connection pipe 55 connecting the strainers 54, and a treated water outlet communicating with the connection pipe 55 56, a drain pipe 57 extending in the vertical direction along the inner peripheral surface of the tower body 50a, and a defoamer aqueous solution injection pipe 58 provided in the vertical direction in the tower body 50a.

  An opening 50b is provided at the top of the tower body 50a, and the inside of the tower body 50a communicates with the atmosphere through the opening 50b.

  The raw water introduction pipe 51 is provided so as to penetrate the lower side wall of the tower body 50a.

  One end of the air pipe 53 penetrates the lower part of the tower body 50a and protrudes outside the tower body 50a, and an air supply pipe from the blower is connected to the tip of the air pipe 53. The other end of the air pipe 53 is connected to the diffuser pipe 52.

  The air pipe 53 rises above the water surface level in the tower body 50a, and one end of the siphon break pipe 53A is connected to the highest portion 53b of the rise. The siphon break pipe 53A is routed downward in the tower body 50a, and the other end side penetrates the lower part of the tower body 50a and projects out of the tower body 50a. A valve 53a is provided at the tip of the siphon break pipe 53A.

  The strainer 54 is installed near the middle in the vertical direction of the tower body 50a or below it. As shown in FIG. 5, the strainer 54 includes a box 54a attached by being bonded to the inner peripheral surface of the tower body 50a, and a screen 54b made of a wedge wire or the like provided on the front surface of the box 54a. The rear surface of the box 54a is open, and the rear end of the box 54a is bonded to the inner peripheral surface of the tower body 50a.

  In this embodiment, two strainers 54 are provided so as to be separated from each other in the vertical direction, and the inside of each strainer 54 is communicated by a connection pipe 55.

  This connection pipe 55 is also a half cylinder, and is bonded to the inner peripheral surface of the tower body 50a. The treated water outlet 56 communicates with the inside of the connecting pipe 55 through an opening provided in the tower body 50a.

  Although illustration is omitted, in order to maintain the inside of the strainer 54, a hand hole is provided in the tower body 50a.

  The drain pipe 57 extends in the vertical direction along the inner peripheral surface of the tower body 50a. Except for the uppermost part, the drain pipe 57 has a half-cylindrical shape as shown in FIG. 4B and is bonded to the inner peripheral surface of the tower body 50a. The uppermost part of the drain pipe 57 has a cylindrical shape and opens into the tower body 50a above the water level. A lower end portion of the drain pipe 57 communicates with a drain outlet 57a at the lower portion of the tower body 50a.

  The defoamer water injection pipe 58 is routed in the vertical direction in the tower body 50a, and the upper end is bent downward in a substantially U shape, and above the water level in the tower body 50a. It is open. The lower end of the water injection pipe 58 penetrates the tower body 50a and protrudes outside the tower body 50a.

  The second biological treatment tank 60 is connected to the cylindrical tower body 60a made of FRP, the treated water inlet 61a having a flange structure provided on the lower side surface of the tower body 60a, and the treated water inlet 61a. A treated water introduction pipe 61 that extends upward along the inner peripheral surface of the body 60a and whose upper end is opened higher than the water level, and an air diffuser 62 provided at the bottom of the tower body 60a, An air pipe 63 for connecting the diffuser pipe 62 to a blower (not shown), a siphon break pipe 63A continuous in the middle of the air pipe 63, a drain pipe 67 extending in the vertical direction along the inner peripheral surface of the tower body 60a, An antifoaming solution injection pipe 68 provided in the vertical direction in the tower body 60a is provided.

  An opening 60b is provided at the top of the tower body 60a, and the inside of the tower body 60a communicates with the atmosphere through the opening 60b.

  The to-be-treated water introduction pipe 61 is halved cylindrical like the raw water introduction pipe 51, and is bonded to the inner peripheral surface of the tower body 60a. As described above, the upper end of the treated water introduction pipe 61 is open in the tower body 60a above the water surface level. The lower end of the to-be-treated water introduction pipe 61 is sealed. A treated water inlet 61 a provided so as to penetrate the lower side wall of the tower body 60 a communicates with a lower end portion in the treated water introduction pipe 61.

  One end of the air pipe 63 penetrates the lower part of the tower body 60a and protrudes outside the tower body 60a, and an air supply pipe from the blower is connected to the tip of the air pipe 63. The other end of the air pipe 63 is connected to the diffuser pipe 62.

  The air pipe 63 rises above the water surface level in the tower body 60a, and one end of the siphon break pipe 63A is connected to the highest position 63b of the rise. The siphon break pipe 63A is routed downward in the tower body 60a, and the other end penetrates the lower portion of the tower body 60a and projects out of the tower body 60a. A valve 63a is provided at the tip of the siphon break pipe 63A.

  The drain pipe 67 extends in the vertical direction along the inner peripheral surface of the tower body 60a. Although illustration is omitted, the drain pipe 67 has a half-cylindrical shape except for the uppermost portion, and is bonded to the inner peripheral surface of the tower body 60a, like the drain pipe 57. The uppermost part of the drain pipe 67 has a cylindrical shape and is open in the tower body 60a above the water surface level. A lower end portion of the drain pipe 67 communicates with a drain outlet 67a at the lower portion of the tower body 60a.

  The defoamer water injection pipe 68 is routed in the vertical direction in the tower body 60a, and the upper end portion is bent in a substantially U shape so as to face downward, above the water level in the tower body 60a. It is open. The lower end of the water injection pipe 68 penetrates the tower body 60a and protrudes outside the tower body 60a.

  In the second biological treatment tank 60, a biological treatment liquid outflow pipe 69 is arranged in the vertical direction. As shown in FIG. 4B, the pipe 69 has a half-cylindrical shape like the pipe 67 and is bonded to the inner peripheral surface of the tower body 60a. The lower portion of the pipe 69 penetrates the side wall of the tower body 60a, and the end thereof has a flange structure, and the tip of a circulation pipe 84 to be described later is connected.

  The upper end of the outflow pipe 69 is an inflow port 69 a for allowing water in the second biological treatment tank 60 to flow in. The level of the inlet 69a is the water level in the second biological treatment tank 60.

  As described above, in FIGS. 3 to 6, the strainer is not used in the second biological treatment tank 60.

  Two valves 71 and 72 are provided in a pipe 70 that connects the treated water outlet 56 of the first biological treatment tank 50 and the inlet 61 a of the second biological treatment tank 60. An air supply pipe 73 having a valve 74 is connected between the valves 71 and 72.

  In addition, although illustration is abbreviate | omitted, in the 1st and 2nd biological treatment tanks 50 and 60, the extraction pipe | tube of excess sludge, the insertion pipe | tube of a surveillance camera in a tank, a wiring penetration opening, a manhole, a spare seat (not shown), etc. Is provided.

  The first and second biological treatment tanks 50 and 60 are filled with a fluidized bed carrier. As the fluidized bed carrier, the same one as in the above embodiment can be used.

  The membrane separation tank 80 includes a tank body 81, a membrane module (separation membrane module) 82 provided in the tank body 81, and an air diffuser 83 provided below the membrane module 82. Air is supplied to the air diffuser 83 from a blower common to the air diffusers 52 and 62.

  A lower inlet 85 of the tank body 81 is connected to the end of the outflow pipe 69 of the second biological treatment tank 60 through a valve 85 a and a pipe 84.

  The lower end of the pipe 87 is connected to the outlet 86 at the upper part of the tank body 81 through a valve 86a. The pipe 87 is drawn into the second biological treatment tank 60 and rises upward along the inner peripheral surface thereof. As shown in FIG. 4B, the pipe 87 has a half-cylindrical shape like the pipes 67 and 69 except for its upper portion, and is bonded to the inner peripheral surface of the tower body 60a. The upper part of the pipe 87 is bent in a U shape above the water level of the second biological treatment tank 60 and opens downward.

  The membrane module 82 may be a system in which flat membranes and hollow fiber membranes are arranged in various shapes in the water tank, but a system in which the membrane surface is installed vertically is suitable. Examples of the type of membrane include MF membrane, UF membrane, and NF membrane. The membrane module 82 may be one that allows water to pass therethrough by water pressure, or may be one that sucks the secondary side of the membrane module 82 with a pump and allows water to pass therethrough.

  A treated water extraction pipe 88 is connected so as to communicate with the inside of the membrane module 82. The pipe 88 passes through the tank body 81 and is drawn out of the tank body 81. A valve 88 a is provided in the pipe 88.

  Connected to the upstream side of the valve 88 a of the pipe 88 is a pipe 90 for injecting a cleaning chemical such as backwash water or hypochlorous acid aqueous solution for cleaning the membrane module 82. The pipe 90 is provided with a valve 91.

  A pipe 89 for discharging settled sludge, membrane module washing waste water, and the like is connected to the lower portion of the tank body 81. The pipe 89 is provided with a valve 89a. During normal water treatment operation, the valves 85a, 86a, and 88a are open, and the valves 89a and 91 are closed.

  In order to treat organic wastewater with this organic wastewater treatment apparatus, raw water (organic wastewater) is introduced into the first biological treatment tank 51 via the introduction pipe 51 of the first biological treatment tank 50, and the diffuser pipe 52. And 70% or more, desirably 80% or more, more desirably 85% or more of the organic component (soluble BOD) is oxidatively decomposed by dispersible bacteria (non-aggregating bacteria). Note that the valve 53a of the pipe 53A is closed during aeration. Suitable conditions such as pH, BOD volume load, carrier filling rate, dissolved oxygen (DO) concentration, etc. of the first biological treatment tank 50 are the same as those in the embodiment of FIGS.

  The treated water (first biological treated water) in the first biological treatment tank 50 is introduced from the outlet 56 into the second biological treatment tank 60 in the subsequent stage through the pipe 70, aerated, and the remaining organic components are oxidized. Reduce excess sludge by decomposition, self-degradation of dispersible bacteria and predation of micro-animals. At this time, the valves 71 and 72 of the pipe 70 are opened, and the valve 73 is closed.

  The air during aeration in the first and second biological treatment tanks 50 and 60 is discharged outside the tower from the openings 50b and 60b at the top of the tower. Bubbles generated during aeration are discharged to drain pits outside the tower bodies 50a and 60a through pipes 57 and 67. A foam sensor is provided in this drainage pit, and when there are many bubbles, an antifoaming agent or water is injected.

  The liquid in the second biological treatment tank 60 is introduced into the membrane separation tank 80 from the outflow pipe 69 through the pipe 84 together with the fluidized bed carrier. By performing air diffusion from the air diffusion tube 83, an upward flow is generated in the membrane separation tank 80. Further, an air lift action is generated in the pipe 87. Thereby, the liquid introduced into the membrane separation tank 80 rises in the tank 80 and is returned from the outlet 86 to the upper part of the second biological treatment tank 60 through the pipe 87. In this tank 80, a part of water permeates the membrane module 82 and is taken out from the pipe 88 as treated water.

  When the air diffuser from the air diffuser 83 strikes the membrane module 82, adhesion and accumulation of sludge on the membrane surface is prevented.

  If the membrane module 82 is clogged, the valves 85a, 86a, 88a are closed, the valves 91, 89a are opened, and a cleaning chemical such as backwash water or hypochlorous acid aqueous solution is supplied from the pipe 90 to the membrane module. The membrane module 82 is back-washed or chemical-cleaned. The cleaning waste liquid is discharged from the pipe 89. In the case of backwashing with water, the valve 89 a may be closed, one or both of the valves 85 a and 86 a may be opened, and the backwash wastewater may not be discharged from the pipe 89. As the backwash water, the permeated water of the membrane module 82 can be used.

  In this embodiment, when the screen 54 b of the strainer 54 of the first biological treatment tank 50 is clogged, the valve 72 is closed and the valve 74 is opened, and air is supplied from the air supply pipe 73 to the strainer of the first biological treatment tank 41. 54 is supplied and backwashed with air.

  When the operation of the biological treatment apparatus is stopped, the valves 53a and 63a are opened to prevent the water in the biological treatment tanks 50 and 60 from flowing back through the pipes 53 and 63 due to the siphon phenomenon.

  The above embodiment shows an example of the embodiment of the present invention, and the present invention is not limited to the illustrated one. For example, in the present invention, the strainer in the first biological treatment tank is omitted, and instead, a membrane separation tank through which the liquid in the first biological treatment tank is circulated is provided, and the permeated water in this membrane separation tank is supplied to the second biological treatment tank. You may comprise so that it may introduce into a biological treatment tank.

  In the present invention, the biological treatment tank may be provided in three or more stages by providing a third biological treatment tank after the first biological treatment tank 1, 50 or the second biological treatment tank 2, 60.

  FIG. 7 is a plan view showing various arrangement patterns of the first biological treatment tank 1 and the second biological treatment tank 2. FIG. 7A shows the first biological treatment tank 1 and the second biological treatment tank 2 installed one by one and connected in series. FIG. 7B shows one first biological treatment tank 1 installed and a plurality of second biological treatment tanks 2 arranged in parallel. FIG. 7C shows a case where a plurality of first biological treatment tanks 1 are installed in parallel and one second biological treatment tank 2 is installed. FIG. 7 (d) shows a series of connected bodies of the first biological treatment tank 1 and the second biological treatment tank 2 arranged in parallel.

  FIGS. 7E and 7F show a plurality of first biological treatment tanks 1 installed in parallel and a plurality of second biological treatment tanks 2 arranged in parallel. In FIG. The number of tanks 1 is greater than that of the second biological treatment tank 2, and the number of second biological treatment tanks 2 is greater than that of the first biological treatment tank 1 in (f). Although illustration is omitted, the first biological treatment tank 1 and the second biological treatment tank 2 may be the same number.

  FIG. 7G shows a plurality of second biological treatment tanks 2 and 2 'installed in series. FIG. 7 (h) shows a configuration in which a plurality of those shown in FIG. 7 (g) are installed in parallel.

  When the first biological treatment tank or the second biological treatment tank is installed in parallel, the remaining first biological treatment tanks are maintained while being stopped and maintained in some of the first biological treatment tanks or the second biological treatment tanks. The operation of the organic wastewater treatment apparatus can be continued using the second biological treatment tank.

  As shown in FIG. 7, according to the present invention, the first biological treatment tank 1 and the second biological treatment tank 2 can be installed in various patterns, and the desired arrangement according to the amount and quality of raw water at the site. can do. In addition, at least one of the first biological treatment tank and the second biological treatment tank is additionally installed in parallel or in series with the existing organic wastewater treatment apparatus of the present invention structure to cope with an increase in raw water flow rate and water quality fluctuation. be able to.

  In the present invention, since the tower bodies of the first and second biological treatment tanks 1, 2 and 50, 60 have the same shape and the same size, even when many biological treatment tanks are installed, the tower bodies are close to each other. Installed, the space between the towers can be reduced, and the installation space of the entire organic wastewater treatment apparatus can be reduced. In addition, the manufacturing cost of the tower is also low. When installing multiple towers in parallel, the structure of each tower is the same, so the installation work of the towers and the pipe connection work of each tower are the same, improving work efficiency and shortening the construction period. be able to.

  Each tower 10, 20, 50a, 60a has a diameter of 2.2 to 3.6 m, especially 2.4 to 3.3 m, a height of 6 to 11 m, particularly 8 to 11 m, and a height H And the ratio H / D of the diameter D is preferably 1.5 to 5.0, particularly 3.0 to 4.5. Moreover, it is preferable that the height from the foundation of the main pipe connection part, the manhole 17, the carrier 13, the strainer 54, the diffuser pipes 12, 22, 52, 62, etc. is 4 m or less, particularly 3.0 m or less. Thus, by providing the connecting portion, the manhole 17, the carrier 13, the strainer 54, the diffuser pipes 12, 22, 52, 62, etc. at a low position, pipe connection work, equipment installation work, and various maintenance work are not high place work. , Work efficiency and safety are improved.

  In this invention, you may make it install an anaerobic processing tank in the front | former stage of the 1st biological treatment tank 1 and 50, and introduce the treated water of an anaerobic treatment tank into a 1st biological treatment tank. The size of the tower body of the anaerobic treatment tank may be the same as that of the tower bodies 10 and 20 or the tower bodies 50a and 60a.

  In this invention, you may install an adjustment tank in the front | former stage of an anaerobic or aerobic processing tank. Examples of the adjustment tank include, but are not limited to, a raw water tank for leveling the raw water flow rate, a settling tank for settling solid matter, and a pressurized flotation device.

  In the present invention, it is preferable that each biological treatment tank is preliminarily attached to a tower with attached equipment such as an air diffuser at the factory, transferred to the site, and installed on the foundation. As a result, the number of work on site can be reduced, the construction period can be shortened, and the assembly accuracy can be improved.

  In the present invention, the distance between the inlet of raw water (treated water) and the outlet of treated water into the biological treatment tank, that is, the distance between the upper end of the raw water introduction pipe 11 and the outlet 14a in FIGS. 3-6, it is preferable that the distance of the upper end part of raw | natural water or to-be-processed water introduction pipes 51 and 61 and the strainer 54 or the inflow port 69a shall be 1.5 m or more, especially 2 m or more. By configuring in this way, the ratio of the short-circuit flow is reduced, and the COD decomposition time can be sufficiently secured.

DESCRIPTION OF SYMBOLS 1,50 1st biological treatment tank 2,60 2nd biological treatment tank 10,20,50a, 60a Tower 12,22,52,62 Aeration pipe 13 Fixed bed or rocking bed support | carrier 15,25 Atmospheric communication pipe 29 Flow Floor carrier 30,80 Membrane separation tank 32,82 Membrane module

Claims (6)

An apparatus for biological treatment of organic wastewater in a biological treatment tank provided in multiple stages,
In the first-stage biological treatment tank, the first biological treatment water in which the dispersal bacteria are increased by the decomposition of the organic matter by the dispersal bacteria is generated,
In the biological treatment apparatus for organic wastewater that generates the second biological treatment water in the second biological treatment tank in the latter stage,
The first biological treatment tank and the second biological treatment tank have towers of the same shape and size, and the height of the tower is 6 to 11 m.
An organic wastewater biological treatment apparatus comprising a membrane separation tank into which a biological treatment liquid is circulated and introduced from a final biological treatment tank.   The biological treatment apparatus for organic wastewater according to claim 1, wherein the ratio (H / D) of the height (H) of the tower body to the diameter (D) is 1.5 to 5.0.   The biological treatment apparatus for organic wastewater according to claim 1 or 2, wherein the installation height of more than half of the pipe connection portions is 3 m or less.   4. The fluidized bed carrier according to any one of claims 1 to 3, wherein each biological treatment tank is filled with a fluidized bed carrier, and a strainer for preventing fluidized bed carrier outflow is provided at a treatment liquid outflow portion of a biological treatment tank other than the final stage. An organic wastewater biological treatment device characterized by   5. The membrane separation tank according to any one of claims 1 to 4, wherein a separation membrane and an air diffuser are provided in the tank, and an organism in the final stage is generated by the upward flow generated by the air diffused from the air diffuser. A biological treatment apparatus for organic wastewater, wherein a biological treatment liquid is circulated between a treatment tank and a membrane separation tank.   The biological treatment method of the organic waste water using the biological treatment apparatus of any one of Claim 1 thru | or 5.

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