WO2016132881A1 - Biological treatment tank, method for operating same and method for treating organic wastewater - Google Patents

Abstract

Provided are: a method for operating a biological treatment tank, whereby a carrier can be fluidized at an early stage of a step for loading the carrier, e.g., at the start of the operation so that the operation can be started in a short period of time; a method for treating organic wastewater; and a biological treatment tank. A device for biologically treating organic wastewater in a biological treatment tank, wherein, at a step for loading a carrier to the biological treatment tank, air is diffused exclusively from a half side of air diffusion tubes to form a circulation flow within the tank, and then air is diffused from all of the air diffusion tubes. The biological treatment tank is provided with a tower of 6-11 m in height, wherein the ratio of the height of the tower to the diameter thereof is 1.5-5.0.

Description

Biological treatment tank, operation method thereof, and organic wastewater treatment method

The present invention relates to a biological treatment tank 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, its operating method, and organic wastewater treatment method. About.

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. Further, since 20 to 40% of the decomposed BOD is converted into bacterial 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.

Many wastewater treatment methods have been devised that use predation of protozoa and metazoans located at a high level 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 is a method described in Patent Document 4 as a biological treatment method of organic wastewater by a multi-stage treatment of fluidized bed and 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.

A concrete water tank is used as a tank body of a conventional biological treatment tank.

The concrete tank has the following problems.
(I) The main body of the tank will be civil engineering work, and the internal equipment will be installed after the tank construction. Concerns remain in terms of construction and quality control.
(Ii) Since the water depth is practically up to about 4 m for practical use, the installation space at the site becomes large.
(Iii) 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 a large installation area.
(Iv) It is difficult to check for liquid leakage from the bottom.
(V) It is necessary to repair the tank lining.

When a fluidized bed type aerobic biological treatment tank is newly installed and the operation is started, a new fluidized bed carrier is introduced into the tank and aeration is started. At this time, if the entire amount of the carrier is put into the tank at a time, most of the carrier remains floating and hardly flows. Furthermore, a gas phase layer is formed between the surface of the carrier group that floats on the water surface due to the entire explosion and the water surface, so that the carrier is not in contact with water and the surface of the carrier is hydrophobic. It is estimated that it takes a long time to get used to. This is because the carrier is made of a material having a bulk specific gravity smaller than 1, such as a sponge. For this reason, conventionally, the carrier is gradually introduced into the tank at different timings, and the carrier is caused to flow by aeration while suppressing the floating of the carrier, so that it takes a long time to introduce the whole amount of the carrier. Similarly, when the carrier is replenished or replaced, there are the same problems as described above.

JP-A-55-20649 JP 2000-210692 A Japanese Patent Publication No. 60-23832 Japanese Patent No. 3410699

The present invention solves such a problem, and allows the carrier to flow quickly at the start of operation or at the time of replenishment or replacement of the carrier, the biological treatment tank having a short start-up time, its operating method, and organic property It aims at providing the processing method of waste water.

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

The biological treatment tank of the present invention is a biological treatment tank provided with an air diffuser at the bottom of the tank, and as the air diffuser, at least a first air diffuser provided on one half side of the bottom of the biological treatment tank And a second air diffuser provided on the other half side, the first supply mode for supplying gas only to the first air diffuser, and the gas to both the first and second air diffusers It is characterized by comprising a gas supply switching means for switching between the second supply mode for supplying gas.

The operation method of the biological treatment tank of the present invention is an operation method of the biological treatment tank in which the carrier is caused to flow by aeration from an air diffuser provided at the bottom of the biological treatment tank containing a fluidized bed carrier having a bulk specific gravity smaller than 1. The step of performing aeration from an air diffuser provided on one half of the bottom of the biological treatment tank to form a vertical circulation flow in the tower, and the step of performing air from all the air diffusers. Features.

In one aspect of the present invention, when a carrier is introduced into the tower, aeration is performed from an air diffuser provided on one half of the bottom of the biological treatment tank to form a vertical circulation flow in the tower.

In the present invention, water may be sprayed into the tower. You may sprinkle defoamer containing water.

In the present invention, the biological treatment tank is preferably a cylindrical tower having a ratio (H / D) of height (H) to diameter (D) of 1.5 to 5.0. .

The organic wastewater biological treatment method of the present invention is a method of biologically treating organic wastewater in a biological treatment tank provided in one or more stages, and at least one biological treatment tank is activated by the operation method of the present invention. It is characterized by that.

In the present invention, in the first-stage biological treatment tank, the first biological treatment water in which the dispersal bacteria are increased is generated by the decomposition of the organic matter by the dispersal bacteria, and the second biological treatment water is produced in the second-stage biological treatment tank. It is preferable to make it. The first biological treatment tank and the second biological treatment tank have towers of the same shape and size, and the height of the towers is preferably 6 to 11 m.

In the present invention, a plurality of first biological treatment tanks and second biological treatment tanks may be installed in parallel.

In the biological treatment tank and the operation method thereof according to the present invention, when the fluidized bed carrier is put into the biological treatment tank, aeration is performed from the air diffuser provided on the half of the bottom of the biological treatment tank, and the biological treatment tank is vertically moved. Since a circulating flow is formed, even a fluidized bed carrier having a bulk specific gravity smaller than 1 is quickly immersed in water and flows. For this reason, starting of a biological treatment tank can be accelerated.

¡By spraying water into the biological treatment tank at the time of activation, the fluidized bed carrier can be submerged and fluidized faster. In this case, by sprinkling the antifoaming agent-containing water, the wettability of the carrier is improved, and aeration bubbles can be prevented from being entangled with the carrier and rising of the carrier.

If a baffle such as a baffle plate or draft tube is installed inside, it will be mixed well by air lift action during single-sided aeration, but it will interfere with mixing when the whole surface is aerated, so the baffle will be installed in the biological treatment tank. It is preferable to have a structure that does not.

The method of the present invention is suitable for application when the specific height (H / D) of the biological treatment tank is large.

The organic wastewater treatment apparatus used in one aspect of the present invention includes a plurality of water treatment units having towers of standard dimensions (same shape, same size), and each water treatment unit is in advance in a factory. Can be produced. In addition, since the size of each tank is unified, the design and construction of the apparatus are made common and can be performed easily and quickly. The space between the tanks can also be reduced. It is easy to add biological treatment tanks.

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.

FIG. 1 is a longitudinal sectional view of an organic wastewater treatment apparatus according to an embodiment. 2a to 2h are plan views showing examples of arrangement of water treatment units in the organic wastewater treatment apparatus of the present invention. FIG. 3 is an explanatory view of water circulation in the biological treatment tank.

Embodiments of the organic wastewater biological treatment apparatus of the present invention will be described in detail below 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 and a second biological treatment tank 2 are erected on a foundation 3 and are connected by a pipe 4. Connected in series.

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 open above the water surface level, the diffuser pipes 12a and 12b provided at the bottom of the tower body 10, and the lower part of the tower body 10 are provided. A screen box 13, a lower end connected to the screen box 13, a riser pipe 14 whose upper end is opened higher than the water surface level, and a side wall near the upper end of the riser pipe 14. And an outflow pipe 15 drawn out of the tower body 10 at the lower part of the tower body 10, a water sprinkler 16 provided at the upper part of the tower body 10, and the like.

The level of the upper end 15a of the outflow pipe 15 is the water level in the tower body 10. The pipe 4 is connected to the end 15 b of the outflow pipe 15.

The tower body 10 is filled with a fluidized bed carrier C. In the screen box 13, the front surface directed toward the center side in the tower body 10 is a screen surface made of a wedge wire or the like. The carrier C does not pass through the screen surface.

The diffuser tube 12a is disposed on one half side of the bottom surface of the tower body 10, and the diffuser tube 12b is disposed on the other half side of the bottom surface. When the bottom surface of the tower body 10 is divided into two with the middle of the one half side where the diffuser tube 12a is arranged and the other half side where the air diffuser tube 12b is arranged as a boundary, the area of the half side region is the area of the bottom surface of the tower body 10 15 to 50%, preferably 20 to 45%.

An opening 17 is provided at the top of the tower body 10, and one end of the atmosphere communication pipe 17 is connected thereto. The atmosphere communication pipe 17 extends downward through the tower body 10, and the lower end is drawn out of the tower body 10 in the immediate vicinity of the foundation 3 and is open toward the atmosphere.

Although not shown in the drawings, a reserve seat that can be opened and closed is provided at the top of the tower body 10, and a manhole and a reserve seat are provided at the bottom.

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. Diffuser pipes 22a and 22b provided at the bottom of the column, a strainer 23 installed slightly below the middle in the vertical direction in the tower body 20, a lower end connected to the strainer 23, and an upper end higher than the water level. A riser pipe 24 that is opened and a branch pipe 25 that branches off from the side surface near the upper end of the riser pipe 24, falls inside the tower body 20, and is drawn out of the tower body 20 at the lower part of the tower body 20; The water sprinkler 26 provided in the upper part of the tower body 20 is provided.

The level of the upper end portion 25a of the outflow pipe 25 is the water level in the tower body 20.

The tower body 20 is filled with a fluidized bed carrier C. The carrier C does not pass through the strainer 23.

The diffuser tube 22a is arranged on one half side of the bottom surface of the tower body 20, and the diffuser tube 22b is arranged on the other half side of the bottom surface. When the bottom surface of the tower body 20 is divided into two with the middle of the one half side where the diffuser tube 22a is arranged and the other half side where the diffuser tube 22b is arranged as a boundary, the area of the half side region is the area of the bottom surface of the tower body 20 15 to 50%, preferably 20 to 45%.

The diffuser tubes 12a, 12b, 22a, and 22b are connected to blowers (not shown) through valves (not shown). By operating each valve, the air supply mode (first supply mode) only to the diffuser tubes 12a and 22a, the air supply mode (first supply mode) to both the diffuser tubes 12a and 12b, and the diffuser tubes 22a and 22b (first) 2 supply modes). That is, by opening the valve of the air diffuser 12a and closing the valve of the air diffuser 12b, air can be supplied to only the air diffuser 12a and one-sided explosion can be performed, and both the valves of the air diffusers 12a and 12b are opened. By doing so, it is possible to supply the air to the diffuser tubes 12a and 12b and to blast the entire surface. 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.

An opening 27a is provided at the top of the tower body 20, and one end of the atmosphere communication pipe 27 is connected thereto. The atmosphere communication pipe 27 extends downward in the tower body 20, and the lower end 27 e is drawn out of the tower body 20 in the immediate vicinity of the foundation 3 and is opened toward the atmosphere.

The top of the tower body 20 is provided with an openable / closable spare seat, and the lower portion is provided with a manhole and a spare seat.

The tower bodies 10 and 20 are preferably made of resin such as FRP in order to eliminate the need for lining, but may be steel plates depending on the water quality. In the case of FRP, it is preferable to apply a weather-resistant paint for the purpose of preventing deterioration due to ultraviolet rays and improving corrosion resistance.

The first and second biological treatment tanks 1 and 2 are provided with an excess sludge extraction pipe, a drain pipe, a wiring insertion port, a sampling port (not shown), and the like. The inside of the tank is monitored with a camera or a photographing device (preferably with illumination or an infrared camera) having a moving image photographing function. 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, install water level gauges, pressure gauges, flow meters, water temperature gauges, water quality gauges, and other measuring instruments in water tanks or peripheral equipment, piping, etc., and use them for monitoring operating conditions, operational control, operational 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.).

<During normal operation>
In order to treat organic wastewater with this organic wastewater treatment device, raw water (organic wastewater) is introduced into the first biological treatment tank 1 through the introduction pipe 11, and aerated and diffused by the diffuser pipes 12a and 12b. 70% or more, desirably 80% or more, more desirably 85% or more of the organic component (soluble BOD) is oxidatively decomposed by a sex bacterium (non-aggregating bacterium). 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 can be ~ 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 residence 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.

By returning a part of the sludge from the subsequent biological treatment tank to the first biological treatment tank 1 or by configuring the first biological treatment tank 1 in a multistage configuration of two or more tanks, a BOD volumetric load of 5 kg / m High load processing of ³ / d or more is also possible.

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, by setting the filling rate of the carrier added to the first biological treatment tank 1 to 10% or less, for example, 1 to 10% in the case of a fluidized bed carrier, the dispersal bacteria that are easy to prey without being affected by the concentration fluctuation. Generation is possible.

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) of the first biological treatment tank 1 is introduced into the second biological treatment tank 2 in the subsequent stage via the pipes 14, 15, 4 and the inlet 21, aerated, and remains. Reduce excess sludge by oxidative degradation of organic components, self-degradation of dispersible bacteria, and predation of micro-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 the fluidized bed carrier C to increase the amount of micro-animal retained in the tank.

The shape of the fluidized bed carrier C 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 C is arbitrary such as a natural material, an inorganic material, or a polymer material, and a gel material may be used. The carrier C has a bulk specific gravity of less than 1 in a dry state, and specifically, a sponge carrier is suitable.

The second biological treatment tank 2 may be further filled with a rocking bed carrier in addition to the fluidized bed carrier.

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 about 0.5 to 30%, particularly about 1 to 10%.

In order to promote predation by 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 floc 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). This floc piece causes clogging of the membrane particularly in the membrane activated sludge method in which membrane separation is performed at a later 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.

For the treated water taken out from the second biological treatment tank 2 through the strainer 23 and the pipes 24, 25, any of solid separation and membrane separation, coagulation sedimentation, and pressurized flotation to obtain a higher quality of treated water May be performed. When performing coagulation sedimentation or pressure levitation, the amount of coagulant added can be reduced. The sedimentation water from the second biological treatment tank 2 may be agglomerated in a coagulation tank, and then precipitated in a solid-liquid separation tank (sedimentation tank) to separate into treated water and sedimented sludge.

In the first and second biological treatment tanks 1 and 2, when foaming occurs due to aeration, it is preferable to spray the defoamer aqueous solution from the sprinklers 16 and 26 to prevent foaming.

FIG. 1 shows an example of an embodiment of the present invention, and the present invention is not limited to the illustrated one. For example, 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 and the second biological treatment tank 2. Conversely, the biological treatment can be only a one-stage treatment using a fluidized bed carrier, for example.

FIGS. 2 a to 2 h are plan views showing various arrangement patterns of the first biological treatment tank 1 and the second biological treatment tank 2. FIG. 2a shows a first biological treatment tank 1 and a second biological treatment tank 2 installed one by one and connected in series. FIG. 2b shows one first biological treatment tank 1 installed and a plurality of second biological treatment tanks 2 arranged in parallel. FIG. 2c shows a plurality of first biological treatment tanks 1 installed in parallel and one second biological treatment tank 2 installed. FIG. 2d shows a series connection of the first biological treatment tank 1 and the second biological treatment tank 2 arranged in parallel.

2e and 2f show a plurality of first biological treatment tanks 1 installed in parallel and a plurality of second biological treatment tanks 2 installed in parallel. In FIG. 2e, the number of first biological treatment tanks 1 is the same. More than the second biological treatment tank 2, and the number of the second biological treatment tank 2 is larger than that of the first biological treatment tank 1 in FIG. Although illustration is omitted, the first biological treatment tank 1 and the second biological treatment tank 2 may be the same number.

FIG. 2g shows a plurality of second biological treatment tanks 2 and 2 'installed in series. FIG. 2h shows a plurality of FIG. 2g 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 FIGS. 2a to 2h, according to the present invention, the first biological treatment tank 1 and the second biological treatment tank 2 can be installed in various patterns, depending on the amount and quality of raw water at the site. It can be an array. 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 this embodiment, since the tower bodies 10 and 20 have the same shape and the same size, even when many tower bodies 10 and 20 are installed, the tower bodies are installed close to each other, and the space between the tower bodies is increased. It is possible to reduce the installation space of the entire organic wastewater treatment apparatus. Moreover, the manufacturing cost of the tower bodies 10 and 20 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 of the towers 10 and 20 has a diameter of 2.2 to 3.6 m, particularly 2.4 to 3.3 m, a height of 6 to 11 m, particularly 8 to 11 m, and a height H and a diameter D. The ratio H / D is preferably 1.5 to 5.0, more preferably 3.0 to 4.5. Moreover, it is preferable that the height from the foundation 3 is 4 m or less, particularly 3.0 m or less, for the main pipe connection part, the manhole, the strainer 23, the diffuser pipes 12a, 12b, 22a, 22b and the like. By providing the pipe connection portion, manhole, strainer 23, diffuser pipes 12a, 12b, 22a, 22b and the like in this way, pipe connection work, equipment installation work, and various maintenance work are not high place work, and work efficiency is improved. And safety is improved.

In the present invention, an anaerobic treatment tank may be installed in front of the first biological treatment tank 1 and the treated water of the anaerobic treatment tank may be introduced into the first 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.

In the present invention, an adjustment tank may be installed in the forefront of the anaerobic or aerobic treatment 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 the tower with attached equipment such as a diffuser pipe 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.

<When loading the carrier and starting operation>
Next, a method for charging the fluidized bed carrier C when starting the operations of the biological treatment tanks 1 and 2 will be described.

When the carrier C is a sponge carrier or the like, it remains floating even if it is put into the tower body 10 or 20, and is hardly submerged even if aeration is performed simultaneously from each air diffuser.

Therefore, in this embodiment, after the carrier is introduced into the tower body 10 or 20, (or prior to the introduction), aeration (single-sided aeration) is performed only from the diffusion tube 12a or 22a. Since the diffuser pipes 12a and 22a are arranged to be biased to one half of the bottom of the tower bodies 10 and 20, when aeration is performed from the diffuser pipes 12a or 22a, bubbles are mainly formed on the inner peripheral surface of the tower body 10 or 20. Of these, since it rises along the inner peripheral surface on one half side, an upflow along the half side is formed in the tower body 10 or 20, and a downflow is formed on the other half side. A circulation flow in the vertical direction is formed in 20. The carrier C introduced into the tower body 10 or 20 is drawn into the water by this downward flow, and becomes compatible with water and flows in the tower bodies 10 and 20.

This point will be described in more detail with reference to FIG.

When a fluidized bed carrier having a bulk specific gravity of less than 1 (when dry, to which no microorganisms have adhered yet) is added to the biological reaction tank and the operation is started, the carrier floats when the entire surface is aerated. Perhaps the surface of the carrier is hydrophobic, and if it is left as it is, a foam film is formed on the surface and floats, and a gas phase layer is formed by aeration between the carrier layer and the water surface, so that the carrier touches the water. It will not be in a state. Therefore, a large eddy current is formed in the tank by performing single-sided aeration. The fluidized bed carrier is mixed to the inside of the tank while being drawn into the downward flow of the vortex. If the water depth of the tank is deep, a plurality of vortex flows may be formed in the vertical direction as shown in FIG. In the present invention, one or more of these vertical vortex flows are collectively referred to as “vertical flow”.

In the present invention, by forming a downward flow temporarily in the tank and forcibly pulling the carrier into the tank, the carrier becomes easy to become familiar with water, especially when the carrier surface is hydrophobic. It is presumed that when the carrier is a porous carrier such as a sponge carrier, water is forcibly soaked into the carrier and the gas inside the carrier is easily replaced with water. In addition, it is considered that the porous carrier is increased in bulk specific gravity (when wet) due to substitution of water in the gas inside the carrier and accumulation of moisture in the carrier, thereby improving sedimentation.

According to the start-up method of the present invention, even if the entire amount of the carrier is put into the towers 10 and 20, the carrier is quickly dispersed in water and starts to flow. The carrier is introduced during single-sided aeration, and the carrier flows into the water after a predetermined time (for example, 5 minutes to 4 days) from the time when the single-sided aeration is started after the introduction of the carrier or after the introduction of the carrier. Then, immediately or after continuing the operation for a while at a low load (for example, 5 minutes to 10 days), the whole blast gas is transferred from all the diffuser tubes 12a and 22a.

When the operation is stopped (water flow stop, aeration stop), the carriers may settle and stick to each other. When this operation is resumed, many of the air bubbles are taken up and floated and mixed sufficiently. Although there is a possibility that it cannot be done, by diverting the present invention, when resuming operation, temporarily aeration on one side and mixing while loosely adhering the fixed carrier, mixing thoroughly and switching to full explosion after switching to full explosion Mix well while preventing. Even when a full-scale explosion is performed, when a carrier is newly put into the tower body 10 or 20, single-sided aeration may be performed, and then the full-scale explosion may be resumed.

At the time of this start-up, water can be sprinkled from the water sprinkler 16 and water can be poured onto the carrier to promote the submergence of the carrier. That is, by sprinkling water onto the carrier, the surface can be dried and the carrier in a hydrophobic state can be forcibly adapted to water, and weight can be applied by attaching or penetrating water to the carrier. . This water may be raw water or treated water.

By sprinkling the antifoaming agent-containing water from the water sprinkler 16 at the time of starting, the effect of coarsening the aerated bubbles and preventing the fine bubbles from being entangled with the carrier and floating the carrier is also obtained. By adding an antifoaming agent, the wettability of the carrier is improved and the water becomes more familiar. That is, when bubbles in the carrier are associated and become larger, the bubbles are discharged out of the carrier and water easily enters the carrier. In addition, the composition of an antifoamer is not specifically limited, The antifoamer composition containing an oil-in-water emulsion can be used.

After the carrier starts to flow, the entire aeration is performed to diffuse from all the diffuser tubes 12a and 12b and the diffuser tubes 22a and 22b. The amount of air diffused during the entire surface aeration is preferably 320 to 600 Nm ³ / h. Single-sided aeration is less diffused than full-surface aeration. For example, when the area of the half-side area by single-sided aeration is 50% of the tower bottom area, the amount of diffused air from single-sided aeration is 160 to 300 Nm ³ / h, half.

[Example 1]
Into the tower 10 having the configuration shown in FIG. 1 having an inner diameter of 2.5 m, a height of 10 m, and a water surface height of 9 m, a 3 mm square sponge carrier 704 kg having a bulk specific gravity of 0.04 g / cm ³ is introduced. When aeration was performed at an aeration amount of 240 Nm ³ / h, all carriers started to flow within 10 min. The area of the region on the half side where the diffuser 12 a is arranged is 50% of the bottom area of the tower body 10.

[Example 2]
In Example 1, when a higher alcohol emulsion type antifoaming agent “Kurires 653” (manufactured by Kurita Kogyo Co., Ltd.) was sprinkled at 100 L / min from the water sprinkler 16 as an antifoaming agent, all the carriers flowed within 5 min. Started.

[Comparative Example 1]
In Example 1, when aeration was performed from the diffuser tubes 12a and 12b at a total aeration amount of 240 Nm ³ / h, most of the carrier floated above the water surface and did not flow even after 7 days.

[Comparative Example 2]
In Example 2, when aeration was performed from the diffuser tubes 12a and 12b at a total aeration amount of 240 Nm ³ / h, it took 7 days for all the carriers to start flowing.

[Comparative Example 3]
In Comparative Example 1, when the total amount of aeration from the diffusing tubes 12a and 12b was 480 Nm ³ / h, most of the carrier floated above the water surface and did not flow even after 7 days.

[Comparative Example 4]
In Comparative Example 2, when the total amount of aeration from the diffusing tubes 12a and 12b was 480 Nm ³ / h, it took 5 days for all the carriers to start flowing.

From the above Examples and Comparative Examples, it was confirmed that the start-up of the biological treatment apparatus when the carrier is loaded can be significantly accelerated according to the present invention.

Although the present invention has been described in detail using specific embodiments, it will be apparent to those skilled in the art that various modifications can be made without departing from the spirit and scope of the invention.
This application is based on Japanese Patent Application No. 2015-027727 filed on February 16, 2015 and Japanese Patent Application No. 2015-183054 filed on September 16, 2015, which is incorporated by reference in its entirety. .

DESCRIPTION OF SYMBOLS 1 1st biological treatment tank 2 2nd biological treatment tank 10,20 Tower 12a, 12b, 22a, 22b Air diffuser 23 Strainer

Claims (10)

1. In the operation method of the biological treatment tank in which the carrier is flowed by aeration from an air diffuser provided at the bottom of the biological treatment tank containing a fluidized bed carrier having a bulk specific gravity smaller than 1.
   Characterized in that it includes a step of aerating from an air diffuser provided on one half of the bottom of the biological treatment tank to form a vertical circulation flow in the tower, and an aerating step from all the air diffusers. To operate the biological treatment tank.
2. In Claim 1, when a support | carrier is injected | thrown-in to the tower body, it aerates from the diffuser pipe provided in the half part of the bottom part in this biological treatment tank, The vertical flow is formed in a tower body, It is characterized by the above-mentioned. Operation method of biological treatment tank.
3. 3. The method for operating a biological treatment tank according to claim 1 or 2, wherein a rectifying mechanism is absent in the tower.
4. 4. The method for operating a biological treatment tank according to any one of claims 1 to 3, wherein the tower is sprinkled with water.
5. 5. The method for operating a biological treatment tank according to any one of claims 1 to 4, wherein the defoamer-containing water is sprinkled.
6. The biological treatment tank according to any one of claims 1 to 5, wherein the biological treatment tank has a cylindrical shape having a ratio (H / D) of height (H) to diameter (D) of 1.5 to 5.0. A method for operating a biological treatment tank, comprising:
7. In a method of biologically treating organic wastewater in a biological treatment tank provided in one or more stages,
   A biological treatment method for organic waste water, wherein at least one biological treatment tank is activated by the method according to any one of claims 1 to 6.
8. In claim 7, in the first-stage biological treatment tank, the first biological treatment water in which the dispersal bacteria increased by the decomposition of the organic matter by the dispersal bacteria,
   A biological treatment method for organic waste water, wherein second biological treatment water is generated in a second biological treatment tank at a subsequent stage.
9. 9. The organic body according to claim 8, wherein the first biological treatment tank and the second biological treatment tank have the same shape and the same size tank body, and the height of the tank body is 6 to 11 m. Biological treatment method for effluent.
10. In a biological treatment tank equipped with an air diffuser at the bottom of the tank,
    As the air diffuser, it comprises at least a first air diffuser provided on one half side of the bottom of the biological treatment tank and a second air diffuser provided on the other half side,
    Gas supply switching means for switching between a first supply mode for supplying gas only to the first diffuser tube and a second supply mode for supplying gas to both the first and second diffuser tubes is provided. A biological treatment tank characterized by that.

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