JP5700537B2 - Air diffuser system and air diffuser cleaning method - Google Patents

Description

  The present invention relates to an aeration system capable of eliminating an increase in aeration resistance due to an adhering substance in an air diffuser of an air diffuser to an aerobic tank having an aerobic microorganism in water treatment using organic matter decomposition by microorganisms. The present invention relates to a method for cleaning an air diffuser.

Conventionally, treated water such as organic wastewater is introduced into an aerobic tank in a water treatment facility such as a sewage treatment plant, and oxygen is diffused into the aquarium to dissolve oxygen by supplying oxygen to the aerobic microorganisms. A diffuser system is known.
In the air diffuser system, an air diffuser is used as a device for dispersing air in the water to be treated in the form of fine bubbles and efficiently dissolving oxygen in the water to be treated.

The air diffusion system is composed of an air blowing means, an air diffusion device, and a pipe connecting both.
The air diffuser includes an air diffuser having air diffuser holes for generating fine bubbles, and is configured to be fixed to a gantry placed in the treatment tank via a holder.
In the air diffuser, the air diffuser has a diffuser plate or diffuser cylinder formed of, for example, ceramics, stainless steel, hard resin, or a resin having elasticity (for example, polyurethane resin) or rubber (for example, EPDM, A membrane diffuser (a diffuser plate type, a diffused cylinder type) formed of neoprene, silicon rubber, or the like is known.

  Depending on the usage environment (treated water quality, etc.) during long-term use, the diffuser is subject to treatment of suspended solids, inorganic precipitates, biological metabolites, etc. in the treated water with the air blown from the diffuser. It adheres to the air diffuser so that it gradually grows from the treated water side of the air diffuser toward the air supply side of the air diffuser from the portion where the water attracted or the water to be treated stays. Ventilation resistance may increase due to narrowing of the road. When the airflow resistance of the air diffuser increases, the power load of the air supply source increases, and energy is wasted. Therefore, there is a need for a method for reliably removing deposits on the air diffuser.

Accordingly, several methods have been reported as means for eliminating the increase in ventilation resistance.
One is to pull up the diffuser from the water to be treated or pull the treated water from the treatment tank to empty it, expose the diffuser, and spray high pressure water directly on the diffuser to remove deposits. This is a cleaning method to be removed.
Another method is to inject the cleaning liquid from the air supply pipe to the air diffuser, fill the air diffuser, that is, the air supply side with the cleaning liquid, and then add the air supply pipe with compressed air from the upstream side of the injection of the cleaning liquid. This is a cleaning method that removes deposits by pressing and discharging the cleaning liquid from the air supply side of the diffuser hole to the treated water side. (For example, refer to Patent Document 1).

Still another method is an operation method in which the humidity of the air supplied to the air diffuser is humidified to a specified value (relative humidity 70% at the water temperature to be treated) or higher (see, for example, Patent Document 2).
According to the air diffusion method and apparatus described in Patent Document 2, it is disclosed that prevention and elimination of adhesion of suspended solids and precipitates in the water to be treated to the air diffusion holes by ejecting humidified air from the air diffusion holes. Has been. It is also disclosed to improve the detergency of aeration holes by adding a chemical to the humidifying water.

Japanese Patent No. 4153250 Japanese Patent No. 4004874

However, as described above, in the method in which high pressure water is directly sprayed on and removed from the deposits on the diffuser, it is necessary to expose the diffuser from the water to be treated. Therefore, the function of the diffuser system is stopped for a long time. In addition, in the water treatment facility, it becomes impossible to decompose organic substances contained in the water to be treated which constantly flows in, and the work becomes complicated.
Also in the method described in Patent Document 1, the function of the target aeration apparatus system must be temporarily stopped in the injection and discharge processes of the cleaning liquid, and the activity of the aerobic microorganisms is greatly reduced. . In addition, since a large amount of cleaning liquid is required to fill the diffuser and the cleaning liquid is pushed out by compressed air and introduced into the aerobic tank, the influence of the cleaning liquid on the water treatment function (for example, the acidity of the cleaning liquid) There is a concern that the degree of alkalinity will cause a decrease in biological treatment function due to changes in pH.

  In the operation method described in Patent Document 2, even under the specified humidity conditions, the amount of cleaning water or the like supplied to the adhering matter in the diffuser holes is supplied in a gasified form such as water vapor, so that the amount is small. Therefore, since peeling due to the swelling effect cannot be expected, the removal of the adhering matter is not sufficient, and the adhering matter to the air diffuser is not removed depending on the use environment (the quality of the water to be treated), and the ventilation resistance increases due to growth. There is a fear. Further, when air of the specified humidity is supplied to the diffuser whose ventilation resistance has been increased, a conveying force for the latent heat of air (water vapor component) is required, and the conveying power may further increase.

In addition, even in the case of an operation method in which a chemical solution is added to the water for humidification, the amount of chemicals that can be vaporized and entrained in the supply air to the air diffuser is limited by gasification. The amount of chemicals that can act on is small. For this reason, the washing water supplied to the adhering matter of the diffused pores is supplied in a gasified form such as water vapor, so the amount is small, and the swelling effect and the dissolving action by the chemical reaction cannot be expected, and the adhering matter can be removed. If the ventilation resistance is not sufficient, the elimination effect is small.
Therefore, the humidifying operation method is intended to prevent deposits from adhering to the air diffuser by always applying it during the time when the air diffuser is operated, and the effect of removing the adhering matter to the air diffuser is small. It is.

  The present invention has been made to solve such a conventional problem, and an object of the present invention is to provide an air diffusion system that can reliably achieve elimination of increase in ventilation resistance due to deposits in the air diffusion holes in a short time. And providing a method of cleaning the air diffuser.

The invention according to claim 1 is an air diffusion system that diffuses air into the water to be treated including organic waste water and biological sludge, and a blower that supplies air, and a dispersion that ejects fine bubbles into the water to be treated. The air diffuser having pores is a gas diffuser film having elasticity, and is provided with a membrane air diffuser that expands when air is supplied to form an air chamber with the support material, from the air supply side of the air diffuser An aeration means for generating fine bubbles in the treated water by jetting air to the treated water side ; and a header pipe or an air main pipe connected to the membrane aeration apparatus and extending upward from the treated water surface It is connected to the discharge side of the blowing means through a flow path, and is connected to the chemical liquid storage means, the compressed air supply means, the chemical liquid storage means and the compressed air supply means, so that the chemical liquid does not stay in the pipe. From the air blowing means And a chemical spraying cleaning means constituted spray particle size for conveying by entrained air in the fine particle spraying means is a two-fluid spray nozzle is 2Myuemu～100myuemu, ventilation resistance due to deposits to the diffusing pores When the flow rate rises , the mist-like chemical solution with a water content ratio of 1.6 to 1.9 with respect to the saturated water vapor amount (relative humidity 100%) at the temperature of the water to be treated is supplied to the flow path having an in- pipe flow velocity of 2 m / s to 5 m / s. In the air chamber of the membrane air diffuser, the mist-like chemical liquid is filled in the membrane air diffuser, and the adhering matter of the air diffuser is dissolved by the chemical liquid and peeled off at a feed pressure. It is characterized in that the adhering matter of the air diffuser is washed from the air supply side of the membrane air diffuser to eliminate the increase in the airflow resistance.

The invention according to claim 2 is the diffusing system according to claim 1, wherein the chemical liquid is a mist that does not stay in the pipe by spraying a liquid composed of an acid, an alkali, an oxidant, or an enzyme alone or a combination of them sequentially. Then, the air is conveyed along with the air from the blowing means.

In the invention according to claim 3 , the air diffuser that diffuses air into the water to be treated containing organic waste water and biological sludge is a diffused film having elasticity and expands when air is supplied. In the method for cleaning a membrane air diffuser that forms an air chamber therebetween, air supplied from the air supply side of the air diffuser hole of the air diffuser by the blowing means is ejected from the air diffuser hole to the treated water side. The flow rate in the pipe is 2 m / s to 5 m / s while maintaining the generation of fine bubbles in the water to be treated at the time of generating air bubbles due to the step of generating fine bubbles in the water to be treated and the increase in ventilation resistance due to the adhering matter to the air diffuser. s, a pipe having a particle size of 2 μm to 100 μm in a water amount ratio of 1.6 to 1.9 with respect to a saturated water vapor amount (relative humidity of 100%) at the water temperature to be treated The mist-like chemical liquid that does not stay inside the blower Entrained with the air from the stage, the mist-like chemical solution is filled in the air chamber of the membrane air diffuser, and the dissolved matter by the chemical solution and the delamination and removal effect at the supply pressure are given to the adhering matter of the air diffuser And the step of cleaning the adhering matter of the air diffuser from the air supply side of the membrane air diffuser to eliminate the increase in the airflow resistance.

Invention, claim 3 Te cleaning method odor diffuser according, washing by prior Symbol mist of drug solution, acid, alkali, alone chemical consisting of oxidizing agents or enzymes or sequentially combining these according to claim 4 It is characterized by performing.

According to the present invention, the chemical liquid is made into a mist with a high cleaning effect by making it mist, and can easily reach each part of the air diffuser by being accompanied by the air, and can be supplied to the air diffuser. Without filling the inside of the apparatus with the chemical solution, the chemical solution can be efficiently brought into contact with the adhering matter in the air holes as droplets having a high cleaning effect. Therefore, the action of dissolving the deposits with the chemical solution and the action of peeling and removing the deposits whose adhesion force decreases with this dissolving action at the air supply pressure ensure that the increase in the airflow resistance due to the deposits of the diffused holes is reliably shortened. It can be solved in time.
In addition, by applying the spray cleaning method, the misted chemical liquid is made into droplets with a high cleaning effect, and the misted chemical liquid is easily accompanied by air to reach each part of the aeration means, thereby improving efficiency. Since it can be distributed to the air diffuser well, the cleaning effect can be obtained with the minimum required chemical solution, and the adverse effect on the water treatment function due to the discharge of the cleaning chemical solution to the treated water (for example, from the degree of acid alkalinity of the cleaning solution) It is possible to carry out cleaning with a minimum of biological treatment function due to pH fluctuation.

Further, during cleaning, the chemical spray cleaning means can be operated only by turning ON / OFF the generation of mist while maintaining the diffuser in a normal diffused state, so that the diffuser can be continuously operated.
In addition, by making the chemical liquid fine particles, the dispersibility of the chemical liquid in the air supply pipe and the air entrainment to the diffused pore adhering site, which is a blocking location, are improved. Even when the apparatus is installed, it is possible to distribute the minimum chemical liquid necessary for cleaning to each air diffuser without filling the pipe with the chemical liquid fed.

It is a key map showing an aeration system concerning one embodiment of the present invention. It is a general | schematic sectional drawing which shows the principal part of FIG. 1 at the time of applying to a diffuser plate type membrane diffuser as a diffuser. It is a figure explaining an effect | action at the time of applying a diffuser plate type membrane diffuser as an example of the diffuser in FIG. It is a general | schematic sectional drawing which shows the principal part of FIG. 1 at the time of applying to a diffused cylinder type membrane diffuser as a diffuser. It is a figure explaining an effect | action at the time of applying a diffused cylinder type membrane diffuser as an example of the diffuser in FIG. It is a schematic diagram which shows the test apparatus for comparing the cleaning method of the diffuser by chemical | medical solution washing | cleaning which concerns on this invention, and the cleaning method of the diffuser by the conventional humidification driving | operation. (A) The figure which shows the condition of the mist confirmation part at the time of a non-humidification driving | operation or a humidification driving | operation, (B) The figure which shows the condition of the mist confirmation part at the time of chemical | medical solution washing | cleaning.

Hereinafter, the present invention will be described based on embodiments shown in the drawings.
1 to 3 show an air diffusion system 1 according to an embodiment of the present invention.
As shown in FIG. 1, the air diffusion system 1 according to the present embodiment includes a treatment tank 10 that is an aerobic tank having aerobic microorganisms used in water treatment facilities such as a sewage treatment plant. In the processing tank 10, for example, three sets of aeration device groups 11 are arranged. The three sets of diffuser groups 11 are configured by connecting a large number of diffuser plate type membrane diffusers 11a in parallel to both sides of one header pipe 19 via connecting pipes 18 respectively.

In the present embodiment, as shown in FIGS. 2 and 3, the diffuser plate type membrane diffuser 11a is made of a resin (for example, polyurethane resin) or rubber (for example, EPDM, etc.) in which the diffuser has elasticity. Neoprene, silicon rubber, etc.).
The diffuser plate type membrane diffuser 11a has a diffuser film 12 formed by forming a stretchable elastic film in a sheet shape on the upper surface of a base plate (for example, stainless steel, hard resin, etc.) 15a. The periphery of the diffuser membrane 12 and the base plate 15 a is configured to be fastened and fixed in a watertight manner by a fixing frame (for example, made of stainless steel) 16. For example, an air supply port (for example, made of stainless steel) 17 is provided in the air diffusion membrane 12 so as to penetrate a part thereof in a watertight manner. The air supply port 17 may be opened on the base plate 15a side. A connection pipe 18 connected to the header pipe 19 is connected to the air supply port 17.

When the air is supplied from the air supply port 17, the diffuser plate type membrane diffuser 11 a expands in a dome shape to form an air chamber 14 between the base plate 15 a and the supply. A large number of air holes 13 for ejecting the generated air are formed, and aeration by the fine bubbles 11 c having a diameter of about 1 mm can be realized in the water to be treated 10 a through the air holes 13.
For example, when the air diffuser 13 has a plurality of small holes formed in a slit shape in the air diffuser membrane 12 and air is not supplied, the air diffuser 13 is formed in the base plate 15a by the elasticity of the air diffuser membrane 12 and the water pressure due to the liquid level of the treated water 10a. Since the air diffuser membrane 12 shrinks along the flat plate, the many small holes are closed, and when air is supplied and the air diffuser membrane 12 expands, the membranes around the small holes follow the expansion of the air diffuser membrane 12. The slit-shaped small holes are opened by being pulled, and a large number of small holes form the air diffusion holes 13.

Each header pipe 19 is connected to an air main pipe 21 via a riser pipe 20. The air main pipe 21 is connected to the blower 22.
Each riser tube 20 is connected with a chemical spray cleaning device 30 as chemical spray cleaning means. In FIG. 1, the chemical spray cleaning apparatus 30 is connected to only one riser pipe 20 and the remaining riser pipes 20 are omitted, but the remaining riser pipes 20 are also located at the positions indicated by the arrows X. It is possible to perform cleaning by connecting the chemical spray cleaning device 30.

The chemical spray cleaning device 30 includes a fine particle spray device (two-fluid spray nozzle) 31 that is a fine particle spray means. The fine particle spray device (two-fluid spray nozzle) 31 atomizes a liquid with a high-speed air flow such as compressed air, and mists (mist or dew) having an average particle diameter of about 2 μm to 100 μm at a low pressure. And can be sprayed.
The state of the produced mist-like chemical liquid corresponds to, for example, dry mist (2 μm to 10 μm) to drizzle (50 μm to 100 μm).

The fine particle spray device (two-fluid spray nozzle) 31 has a jet port 31 a connected to each riser pipe 20. The fine particle spray device (two-fluid spray nozzle) 31 is provided with two fluid connection ports 31b and 31c.
A cleaning chemical liquid supply pipe 34 that supplies the cleaning chemical liquid stored in the cleaning chemical liquid storage tank 32 by the cleaning chemical liquid constant supply device 33 is connected to the one fluid connection port 31b. In the cleaning chemical solution supply pipe 34, a back pressure valve 35 is installed between the cleaning chemical solution fixed supply device 33 and the fine particle spray device 31 in order to set the discharge pressure of the cleaning chemical solution fixed supply device 33 to a predetermined value or more. . In addition, a pressure gauge 36 for checking the discharge pressure of the cleaning chemical liquid supply device 33 is installed.

A compressed air supply pipe 38 that supplies compressed air from the compressed air supply device 37 is connected to the other fluid connection port 31c. The compressed air supply pipe 38 is provided with a pressure reducing valve 39 for adjusting the supply pressure, a flow rate adjusting valve 40 for adjusting the supply amount, and a flow meter 41 for checking the supply amount.
The cleaning chemical liquid is an acid, an alkali, an oxidizing agent, an enzyme, or the like, and is used alone or in combination according to the deposit A. For example, washing with an alkali (caustic soda, etc.) or an oxidizing agent (sodium hypochlorite, hydrogen peroxide) mainly targeting organic substances in the deposit A, and an acid (formic acid, mainly targeting inorganic precipitates) In combination with cleaning with acetic acid or the like, it is possible to reliably obtain an effect against an increase in airflow resistance due to adhesion of a complex of an organic substance and an inorganic substance that is difficult to resolve with one kind of chemical solution. .

Next, based on FIG. 1 thru | or FIG. 3, the effect | action of the air diffusion system 1 which concerns on this embodiment is demonstrated.
In a normal operation, the air diffuser plate type membrane diffuser from the air supply port 17 to the diffuser plate type membrane diffuser 11a through the air main pipe 21, the riser pipe 20, the header pipe 19 and the connecting pipe 18 from the blower 22. When air is blown against the water pressure of the treatment tank 10 in which the apparatus 11a is installed, for example, as shown in FIGS. 2 and 3, the diffuser plate type membrane diffuser 11a has the diffuser film 12 as shown in FIG. The air chamber 14 is formed between the base plate 15a and the base plate 15a, and a large number of air holes 13 for ejecting the supplied air are formed. Through the air holes 13, fine bubbles 11c are formed in the water to be treated 10a. Realize aeration.

In this way, by generating the fine bubbles 11c in the water to be treated 10a in the treatment tank 10, an aeration process is performed in which air is diffused and aerated in the water to be treated 10a. And oxygen is supplied to the microorganisms in the to-be-processed water 10a, and the to-be-processed water 10a biological treatment is performed.
During this normal operation, depending on the usage environment (the quality of the water to be treated, etc.), for example, the deposit A may be generated in the air diffusion holes 13 due to inorganic precipitates or the like from the water to be treated 10a.

In this embodiment, when an increase in ventilation resistance due to the deposit A of the air diffuser 13 is detected, the adhering matter of the air diffuser 13 is maintained while maintaining the air diffuser plate type membrane diffuser 11a in a normal air diffused state. In order to eliminate the increase in ventilation resistance due to A, the chemical spray cleaning device 30 is driven.
The cleaning chemical solution stored in the cleaning chemical solution storage tank 32 is supplied to the fluid connection port 31 b of the fine particle spray device 31 by the cleaning chemical solution supply device 33 via the cleaning chemical solution supply pipe 34.
At the same time, compressed air is supplied from the compressed air supply device 37 to the fluid connection port 31 c of the fine particle spray device 31 through the compressed air supply pipe 38.

In the fine particle spray device 31, for example, as shown in FIG. 2, a cleaning chemical solution and compressed air are mixed to make fine particles, and the chemical solution is mist having an average particle diameter of about 2 μm to 100 μm from the jet port 31a into the riser tube 20. And spray.
The sprayed chemical liquid particles are distributed and transferred to a plurality of diffuser plate type membrane diffusers 11a installed in the header pipe 19 along with the supply air from the blower 22 to the diffuser plate type membrane diffuser 11a. Is done. During the spraying of the chemical solution, the chemical solution does not stay in the riser pipe 20, the header pipe 19, and the connection pipe 18, and is transferred to the air diffuser plate type membrane diffuser 11 a along with the supply air from the blower 22. The Then, in the air chamber 14 of the diffuser plate type membrane diffuser 11 a, the supply air is filled with the mist M of the chemical solution and comes into contact with the deposit A of the diffuser holes 13.

Therefore, from the inner side (air supply side) of the diffuser membrane 12 to the deposit A of the diffuser hole 13, the dissolving action by the chemical solution and the supply pressure to the deposit A having a reduced adhesion force accompanying this dissolving action. It is possible to provide an exfoliation and removal effect and to wash efficiently.
At this time, the chemical solution is used alone or in combination, with the acid, alkali, oxidizing agent, enzyme, etc., in accordance with the deposit A.

  As described above, according to the present embodiment, the chemical spray cleaning device 30 is driven to maintain the diffuser plate type membrane diffuser 11a in the normal diffused state during cleaning, and the fine particle spray device 31 The cleaning chemical liquid is made into fine particles from the jet nozzle 31a and sprayed into the riser pipe 20, the header pipe 19 and the connecting pipe 18, and the chemical liquid which has been made mist using air as a transfer medium is used as air in the diffuser plate type membrane diffuser 11a. In the air chamber 14, the supply air is filled with the mist M of the chemical solution so as to be in contact with the deposit A of the diffuser hole 13, and the deposit A of the diffuser hole 13 is made of the chemical solution. Dissolving action and separation and removal action at the air supply pressure for the deposit A whose adhesion force has decreased due to the dissolving action are given, and air diffuser holes from the inside (air supply side) of the air diffuser plate type membrane air diffuser 11a 13 It can be cleaned.

  In this embodiment, the dispersibility of the chemical liquid in the riser pipe 20, the header pipe 19, and the connection pipe 18 is improved by making the chemical liquid into fine particles by using a fine particle spray device 31 such as a two-fluid spray nozzle. Even when a large number of diffuser plate-type membrane diffusers 11a are installed in the header tube 19, the diffuser plate-type membrane diffuser without filling the riser tube 20 and the header tube 19 with cleaning chemicals. Since the cleaning chemical liquid can be efficiently transferred and acted on the deposit A of the air diffuser 13 of the device 11a, it is possible to reliably obtain a cleaning effect by a short time cleaning with the minimum necessary chemical liquid. .

4 and 5 show another example in which a diffuser cylinder type membrane diffuser 11b is used instead of the diffuser plate type membrane diffuser 11a.
As shown in FIGS. 4 and 5, the diffuser type membrane diffuser 11 b is made of a resin (for example, polyurethane resin) or rubber (for example, EPDM, neoprene, silicon rubber, etc.) in which the diffuser has elasticity. It is comprised by the cylindrical diffuser film 12 formed by.
The diffusion cylinder type membrane diffuser 11b is provided with an air supply port 17 screwed into a large number of holes (not shown) provided in the header pipe 19 on one side, and the other side by a closing body 15c. The cylindrical diffuser membrane 12 is arranged on the outer periphery of the closed support cylinder 15b, and both ends of the diffuser membrane 12 are fastened and fixed.

  The diffuser cylinder type membrane diffuser 11b configured as described above is connected to the air supply port 17 from the blower 22 via the air main pipe 21, the riser pipe 20, and the header pipe 19 in the same manner as the diffuser plate type membrane apparatus 11a. When air is blown into the diffusion cylinder type membrane diffusion device 11b against the water pressure of the treatment tank 10 in which the diffusion cylinder type membrane diffusion device 11b is installed, for example, as shown in FIGS. The diffuser-type membrane diffuser 11b forms an air chamber 14 between the diffuser membrane 12 and the support tube 15b, and a large number of diffuser holes 13 for ejecting the supplied air. Aeration by the fine bubbles 11 c is realized in the water to be treated 10 a through the air diffusion holes 13.

In this way, by generating the fine bubbles 11c in the water to be treated 10a in the treatment tank 10, an aeration process is performed in which air is diffused and aerated in the water to be treated 10a. And oxygen is supplied to the microorganisms in the to-be-processed water 10a, and the to-be-processed water 10a biological treatment is performed.
During this normal operation, depending on the usage environment (the quality of the water to be treated, etc.), for example, the deposit A may be generated in the air diffusion holes 13 due to inorganic precipitates or the like from the water to be treated 10a.
Also in this example, as in the case of the diffuser plate type membrane diffuser 11a, when an increase in ventilation resistance due to the deposit A of the diffuser hole 13 is detected, the diffuser cylinder type membrane diffuser 11b is changed to a normal diffuser. In order to eliminate the increase in ventilation resistance due to the adhering matter A of the diffuser holes 13 while maintaining the gas state, the chemical spray cleaning device 30 is driven. In the fine particle spray device 31, for example, as shown in FIG. The cleaning chemical solution and compressed air are mixed and made into fine particles, and the chemical solution is made into a mist having an average particle diameter of about 2 μm to 100 μm and sprayed into the riser pipe 20 from the ejection port 31a.

The sprayed chemical liquid particles are distributed and transferred to a plurality of diffused cylinder type membrane diffusers 11b installed in the header pipe 19 along with the supply air from the blower 22 to the diffused cylinder type membrane diffuser 11b. . During the spraying of the chemical solution, the chemical solution does not stay in the riser pipe 20 and the header pipe 19 and is transferred to the air diffuser type membrane diffuser 11b with the supply air from the blower 22. Then, in the air chamber 14 of the diffusion cylinder type membrane diffuser 11b, the supply air is filled with the mist M of the chemical solution and comes into contact with the deposit A of the diffuser holes 13.
Therefore, from the inner side (air supply side) of the diffuser membrane 12 to the deposit A of the diffuser hole 13, the dissolving action by the chemical solution and the supply pressure to the deposit A having a reduced adhesion force accompanying this dissolving action. It is possible to provide an exfoliation and removal effect and to wash efficiently.

In the above embodiment, the diffuser plate type membrane diffuser 11a and the diffuser cylinder type membrane diffuser 11b have been described as the diffuser. However, the present invention is not limited to these, for example, the diffuser unit. Alternatively, an air diffuser equipped with an air diffuser plate or an air diffuser using a porous body (aggregate of air diffuser holes) of a non-stretchable material (for example, ceramics, stainless steel, hard resin, etc.) may be used.
A diffuser plate that uses a porous body made of a non-stretchable material (for example, ceramics, stainless steel, hard resin, etc.) for the diffuser, and the porous body, holder (for example, stainless steel, synthetic resin, concrete, etc.) In a state where a synthetic rubber (for example, EPDM) packing is installed between the porous body and the holder, and is fastened and fixed in a watertight manner by a fixing bracket (for example, stainless steel). It is configured. The holder is provided with an air supply port (for example, made of stainless steel). A connection pipe that communicates with the header pipe is connected to the air supply port.

A diffuser using a porous body made of a non-stretchable material (for example, ceramics, stainless steel, hard resin, etc.) for the diffuser part is supplied with air supplied from the blower from the porous body (aggregate of diffuser holes) of the diffuser part. Fine bubbles are generated by jetting.
Even in a device using a non-stretchable material (for example, ceramics, stainless steel, hard resin, etc.) in a diffused part (aggregate of diffused pores), depending on the usage environment (treated water quality, etc.) There is a risk of increased ventilation resistance due to deposits.

Next, based on FIG.6 and FIG.7, the cleaning method of the diffuser by chemical | medical solution washing | cleaning which concerns on this invention, and the clogging prevention of the diffuser by the humidification operation currently disclosed by patent document 2 etc. and elimination Differences from the method will be explained by comparative tests.
A test apparatus 50 for performing this comparative test includes a heater 51, a temperature / humidity meter (TH1) 52, a blower 53, an air supply pipe (corresponding to a riser pipe) 54, an air flow meter 55, and a pressure gauge from the upstream side toward the downstream side. 56, fine particle spraying device (used for humidification operation and chemical cleaning) 57, thermohygrometer (TH2) 58, air cooling double pipe (in the treatment tank so as to correspond to the latter half of the riser pipe and header pipe located in water) Reproduction of cooling of supply air by water to be treated in 59), temperature / humidity meter (TH3) 60, air cooling double pipe (water to be treated in the treatment tank so as to correspond to a header pipe and a connecting pipe located in water) 61), temperature and humidity meter (TH4) 62, sight glass (acrylic transparent tube) 63, laser visualization device 64, air flow pressure control valve (air is blown out against this pressure loss against water pressure) The And a set) 65 to reproduce the air pressure loss in the membrane air diffuser 11a of the case was.

  The two air cooling double pipes 59 and 61 are connected to the circulating water pipe 66a and are connected to the circulating water pipes 66b and 66c for circulating the cooling water in the water circulating tank 70 sent by the cooling pump 68, so that the pipe cooling device is connected. 71 is constituted. A thermometer 69, a heater 67, and a pump 68 are provided in the water circulation tank 70, and the water temperature is adjusted to be maintained at the water temperature to be treated (25 ° C.).

In this comparative test, the following three tests were performed.
(1) Test (non-humidified operation)
Under the condition where air is supplied from the blower 53 to the air supply pipe 54, the temperature in the air supply pipe 54 during the non-humidifying operation in which water is not sprayed into the air supply pipe 54 from the fine particle spraying device 57 installed on the air supply pipe 54. The change in humidity was measured by three thermohygrometers (TH2 to TH4) 58, 60, 62.

(2) Test (humidification operation)
In a situation where air is supplied from the blower 53 to the air supply pipe 54, an amount equivalent to humidification (relative humidity 70 at the water temperature to be treated (25 ° C.)) is supplied into the air supply pipe 54 from the fine particle spraying device 57 installed on the air supply pipe 54. The change in temperature and humidity in the air supply tube 54 when spraying water (% to 100% equivalent) was measured with three thermohygrometers (TH2 to TH4) 58, 60, and 62.
(3) Test (chemical solution cleaning)
In a situation where air is supplied from the blower 53 to the air supply pipe 54, an amount equivalent to chemical cleaning (for example, at a water temperature to be treated (25 ° C.) in the air supply pipe 54 from the fine particle spraying device 57 installed on the air supply pipe 54. The temperature and humidity changes in the air supply pipe 54 when spraying water with a water content equivalent to 1.6 to 1.9 times the water content of saturated air with a relative humidity of 100% were measured with three thermohygrometers ( (TH2-TH4) 58, 60, 62.

  At the same time, the sight glass (acrylic transparent tube) 63 and the laser visualization device 64 installed at the end of the air supply tube 54 correspond to immediately before the air supply port 17 for supplying air to the membrane air diffuser 11a during air supply. The presence or absence of mist at the site was confirmed, and the state during humidification operation was compared with the state during chemical cleaning. The presence of mist was confirmed in a state where fine particles passing through a 45-degree vertical section (with respect to the air flow direction) of the sight glass (acrylic transparent tube) 63 were visualized with laser light.

In the comparison test, the air flow rate (flow velocity) and the air supply pressure are adjusted by the air flow pressure adjustment valve 65 at the end of the air supply pipe 54, and the equipment conditions of the aeration system used in the aerobic tank of a general sewage treatment facility are determined. Performed under reproducible conditions.
In addition, the general air supply volume and air supply pressure equipment conditions were defined as follows.
General air supply rate: Air supply rate at which the flow velocity in the riser pipe is 2 m / s to 5 m / s
Flow rate 2 m / s : Equivalent to the minimum operating flow rate of the membrane diffuser
Flow velocity 5 m / s : Equivalent to the design standard flow velocity (equipment design value) of the riser pipe General air supply pressure: Air supply pressure 55 kPa (air supply pressure during membrane diffuser operation)
Breakdown: Aeration water depth 4.0m (about 40kPa)
Loss of piping, etc. (valves, flow meters) 4 kPa
Membrane diffuser pressure loss 11kPa
Total: 55kPa

The pipe cooling devices 59 and 61 installed downstream of the position of the fine particle spraying device 57 set the length corresponding to the diffused water depth, and circulates the water to be treated (25 ° C.) to circulate the treatment tank 10. It was installed to reproduce the cooling of the air by the water to be treated 10a.
The test results are shown in Tables 1 and 2.

At the time of reproduction of the humidification operation under the conditions of a flow rate of 2 m / s and a flow rate of 5 m / s , the measurement result of the thermohygrometer (TH4) 62 installed at the end of the test apparatus 50 is the specified value of the humidification operation (water temperature to be treated ( In order to confirm the inside of the air supply pipe 54 in a state where the water content ratio with respect to 100% relative humidity at 25 ° C. is 0.97 and 0.98), as shown in FIG. When the fine particles passing through the 45-degree vertical section (with respect to the air flow) of the (acrylic transparent tube) 63 are visualized with laser light, the mist confirmation part a in the sight glass (acrylic transparent tube) 63 As in the non-humidified operation, the presence of stagnant water and mist was not confirmed.
In addition, when the measurement results of the thermohygrometers (TH1 to TH4) 52, 58, 60, and 62 during the humidification operation and the balance of the amount of spray water were confirmed, the consistency of the moisture balance in this test was confirmed.

On the other hand, at the time of reproduction of chemical solution cleaning under conditions of a flow rate of 2 m / s and a flow rate of 5 m / s , the assumed result of the thermohygrometer (TH4) 62 installed at the end of the test apparatus 50 is the relative humidity detection upper limit (99.9% ), A 45-degree vertical section (with respect to the air flow) of the sight glass (acrylic transparent tube) 63 is taken as shown in FIG. 7B. When the passing fine particles were visualized by laser light, no stagnant water was seen in the mist confirmation part a in the sight glass (acrylic transparent tube) 63, and the presence of a large amount of mist M was confirmed.
Since the presence of stagnant water was not confirmed in the air supply pipe 54 after the chemical cleaning was reproduced, the non-evaporated portion of the water sprayed in the air supply pipe 54 was accompanied by mist during the air supply and transferred outside the test apparatus. It was shown that

As described above, from the result of the comparative test between the cleaning method of the diffuser by the chemical cleaning according to the present invention and the cleaning method of the diffuser by the conventional humidifying operation, both types of the presence of mist being supplied It was confirmed that there was a clear difference in the presence or absence.
From this, it was considered that in the conventional method for cleaning an air diffuser by a humidifying operation, water (gas) is the only water that acts on the deposits in the diffuser holes, and the dissolution action of the deposits is small. In addition, even when chemicals are added to the water for humidification, the chemicals that act on the deposits are in a gas or solid state, and the amount of chemicals that can act is the amount that can be entrained as a gaseous state during air supply. Due to the limitations, it was thought that the action of dissolving the deposits was small and it took a long time for cleaning.

  On the other hand, in the method for cleaning an air diffuser by chemical liquid cleaning according to the present invention, the misted chemical liquid can be transferred along with the air supply, so that the misted chemical liquid is dispersed in the membrane air diffuser. It can be efficiently supplied in a state with high properties. For this reason, the chemical solution that has been misted is brought into direct contact with the deposit, and the deposit is dissolved by the chemical in a short period of time. Therefore, it is possible to surely eliminate the increase in ventilation resistance due to the attached matter.

DESCRIPTION OF SYMBOLS 1 Air diffusion system 10 Treatment tank 10a Water to be treated 11 Air diffuser group 11a Air diffuser plate type membrane air diffuser 11b Air diffuser cylinder type membrane air diffuser 11c Fine bubble 12 Air diffuser membrane 13 Air diffuser hole 14 Air chamber 15a Base plate 15b Support cylinder 19 Header pipe 20 Riser pipe 21 Air main pipe 22 Blower 30 Chemical liquid spray cleaning apparatus 31 Fine particle spray apparatus (2 fluid spray nozzle)
32 Cleaning chemical liquid storage tank 33 Cleaning chemical liquid fixed supply device 34 Cleaning chemical liquid supply pipe 37 Compressed air supply apparatus 38 Compressed air supply pipe A Deposit M Mist of chemical liquid

Claims (4)

In the diffuser system that diffuses air into the treated water containing organic wastewater and biological sludge,
The air chamber between the support member and the blowing means for supplying air and the air diffuser having air diffuser holes for ejecting fine bubbles in the water to be treated are a diffused film having elasticity. An air diffuser for generating fine bubbles in the water to be treated by ejecting air from the air supply side of the air diffusion holes to the water to be treated.
It is connected to the discharge side of the blowing means via a flow path that is a header pipe or an air main pipe that is connected to the membrane diffuser and extends upward from the water surface to be treated , a chemical solution storage means, a compressed air supply means, A two-fluid spray nozzle connected to the chemical solution storage means and the compressed air supply means, and having a spray particle diameter of 2 μm to 100 μm that is conveyed in the form of a mist that does not stay in the pipe with the air from the blowing means. A chemical spray cleaning means comprising a fine particle spray means ,
Moisture ratio 1 to saturated water vapor (relative humidity 100%) at the temperature of the water to be treated into the flow channel having a flow velocity in the pipe of 2 m / s to 5 m / s when the airflow resistance increases due to the deposits on the air diffusion holes 6 to 1.9, the mist-like chemical liquid is entrained in the air from the air blowing means , the mist-like chemical liquid is filled in the air chamber of the membrane air diffuser, Dispersing action by a chemical solution and peeling and removing action at air supply pressure are given, and the adhering pores are washed from the air supply side of the membrane air diffuser to eliminate the increase in the airflow resistance. Qi system. The aeration system according to claim 1.
The chemical solution is characterized in that it is sprayed with a liquid consisting of an acid, an alkali, an oxidant, or an enzyme alone or a combination thereof in order to form a mist that does not stay in the piping, and is carried along with the air from the blowing means. Air diffuser system. A membrane that diffuses air into treated water containing organic wastewater and biological sludge is a diffused membrane with elasticity, and expands when air is supplied to form an air chamber between the support material and the membrane In the method of cleaning the air diffuser,
  A step of causing fine air bubbles to be generated in the water to be treated by blowing air supplied from the air supply side of the air diffuser of the air diffuser by the blowing means to the water to be treated from the air diffuser;
  To the discharge-side flow path of the blowing means having an in-pipe flow velocity of 2 m / s to 5 m / s while maintaining the generation of fine bubbles in the water to be treated at the time of increase in ventilation resistance due to deposits on the air diffusion holes, A mist-like chemical solution that does not stay in the pipe and has a water content ratio of 1.6 to 1.9 with respect to a saturated water vapor amount (relative humidity of 100%) at the water temperature to be treated is 2 μm to 100 μm. The mist-like chemical liquid is filled in the air chamber of the membrane air diffuser, and the adhered action of the air diffused hole is given a dissolving action by the chemical liquid and a peeling removal action at a feed pressure, Cleaning the adhering matter from the air supply side of the membrane air diffuser to eliminate the increase in the airflow resistance;
  A method for cleaning an air diffuser characterized by comprising: In the washing | cleaning method of the aeration apparatus of Claim 3,
  The cleaning with the mist-like chemical solution is performed by using a chemical solution composed of an acid, an alkali, an oxidizing agent or an enzyme alone or in combination.
  A method for cleaning an air diffuser.

Images