JP3328139B2 - Method and apparatus for producing activated sludge - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the production of activated sludge for treating organic wastewater such as household wastewater, livestock wastewater, processed marine wastewater, and processed agricultural wastewater.

[0002]

2. Description of the Related Art Hitherto, as a biological treatment method of various wastewaters, an activated sludge method, an aerobic treatment method such as a trickling filter, an anaerobic treatment method of decomposing under anoxic conditions, and the like have been adopted. . In any of these treatment methods, treatment is performed using only microorganisms that naturally occur in the process of treating organic wastewater. However, treating these microorganisms with organic wastewater in an artificial environment has reached the limit in various aspects, and the following problems have occurred.

(1) In the process of treating organic wastewater, malodorous substances such as low molecular weight organic acids, ammonia, hydrogen sulfide, and mercaptan are generated, and the surrounding environment is deteriorated. (2) The amount of sludge generated by the treatment of organic wastewater has increased, and a great deal of expense has been spent in treating the sludge. (3) The generated sludge regenerates an odor and is difficult to handle due to poor concentration, poor dehydration, and the like.

Various apparatuses have been developed to solve such problems. As a typical apparatus, a reactor type activated sludge producing apparatus is disclosed in Japanese Patent Application Laid-Open No. 7-124580 and Japanese Patent Publication No. 5-10999. Etc.
These are mixed contact of a microorganism culturing agent (a culturing agent or a microorganism metabolic circuit inducer) housed in a reactor with a liquid to be cultured (or an organic wastewater) to form useful bacteria having a high purification ability. It is a device for efficiently culturing and converting the metabolic reaction of microorganisms into a metabolic circuit that is efficient for purification of organic wastewater. By utilizing microorganisms cultured in these devices for various organic wastewater treatments, it is possible to solve the above-mentioned problems such as the bad odor and the deterioration of the quality of sludge.

[0005]

However, these devices have a problem of clogging. All of these devices directly contact the microbial culture medium and the medium to be cultured, and with the passage of time, the surface of the microbial culture medium, the gap between the microbial culture medium, and a wire mesh or punching metal for holding the microbial culture medium In the gaps of the culture medium, the adhered substance and the lump substance in the culture solution gradually accumulate. As the accumulation progresses, clogging also progresses synergistically, resulting in poor contact between the liquid to be cultured and the microbial culture medium and the uneven oxygen concentration in the liquid to be cultured, resulting in a decrease in the processing efficiency of the reactor. Will come. Periodically clean the clogged microbial culture media and wire mesh
It is necessary to replace the battery, which leads to complicated maintenance and running costs.

Another problem is that the microbial culture is depleted. This is a problem particularly found in the device disclosed in Japanese Patent Publication No. 5-10999. This device performs aeration from the lower side of the microorganism culture agent, and has a structure in which the flow of air bubbles directly collides with the microorganism culture agent, so that the depletion of the microorganism culture agent is accelerated. Therefore, it is necessary to newly replenish the depleted amount of the microorganism cultivation agent, so that maintenance and management are troublesome and the running cost is also increased.

[0007] The present invention has been made in view of the above-mentioned problems of the prior art, and has as its object to improve the cultivation efficiency by eliminating the risk of clogging and minimizing the depletion of the microorganism culture medium. Another object of the present invention is to provide a method and an apparatus for producing activated sludge, which enable simplified maintenance and reduced running costs.

[0008]

According to the present invention, in order to solve the above-mentioned problems, an extract is produced by bringing a solvent for an extract into contact with a microorganism culturing agent in an extraction tank. Into an incubation tank, where it is mixed with the liquid to be cultured and cultured under aerobic conditions to produce activated sludge, a method for producing activated sludge, an inlet for an extractant solvent and an outlet for an extract. And an extraction tank in which a microbial culture medium is stored, an extractant inlet connected to the extract outlet, and a culture inlet, and an air diffuser is provided therein. An apparatus for producing activated sludge comprising a culture tank.

The "activated sludge" in the present invention is not a "sludge having a high microbial activity" used in the activated sludge method, but a culture solution in which the microbial activity of a liquid to be cultured is increased by the action of a microbial culture agent. It refers to a culture solution in which useful bacteria are cultured, a culture solution in which microorganisms whose metabolic circuit is converted are cultured, and the like.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described with reference to the drawings showing embodiments, but it is needless to say that the present invention is not limited to the embodiments. In FIG. 1, 1
Denotes an extraction tank, 2 denotes a culture tank, and both tanks are connected by an extract transfer pipe 3. Reference numeral 4 denotes a cylindrical extraction tank main body, and reference numeral 5 denotes a cylindrical body which is disposed inside the extraction tank main body 4 so as not to have a gap with its inner wall, and is filled with a microorganism culturing agent 6. The upper and lower ends of the cylindrical body 5 are open, and a bottom plate 7 and a top plate 8 made of wire mesh or punched metal are attached to the upper and lower ends thereof, and serve to store the microorganism culture agent 6 in the cylindrical body 5. .

The microorganism culturing agent 6 filled in the cylindrical body 5 is
A substance containing an effective ingredient for producing activated sludge.Specifically, it is a useful microbial culture agent in the form of pellets, far-infrared ceramics, rocks, minerals, substances containing humus, and antibacterial against microorganisms other than useful bacteria. Suitable substances include substances having an effect and mixtures thereof, but are not limited thereto. On the upper side of the extraction tank main body 4, an inflow port 10 through which the solvent 9 of the extraction liquid flows, an overflow drain port 11 for discharging excess solvent or extract from the extraction tank main body 4, and an extraction tank main body 4. A water level sensor 12 for setting the inflow amount of the flowing solvent 9 is provided.

The solvent 9 used here is a microorganism culturing agent 6
It works to extract effective components from water, specifically, water or treated water in a sewage treatment facility, raw sewage, a mixed solution in an aeration tank, a mixed solution in an anaerobic tank, and the like, alone or mixed. Used. In particular, in the case where mainly organic components are extracted from the substance containing the humus, the extraction efficiency is improved by setting the pH of the solvent to a neutral or alkaline side.

Reference numeral 13 denotes a circulating flow generator provided outside the main body 4 of the extraction tank, which is connected to circulating flow pipes 14 and 15 connected to the main body 4 of the extraction tank at upper and lower positions of the cylindrical body 5. The circulating flow generating device 13 has a function of forcibly generating a circulating flow in the extraction tank main body 4 and effectively bringing the solvent 9 and the microorganism culturing agent 6 into contact with each other, thereby greatly improving the extraction efficiency. . FIG. 1 shows an example in which the circulating flow is in a counterclockwise direction (arrow), but may be in a clockwise direction. Examples of the circulating flow generator include an air lift pump and a water flow pump, but any device can be used as long as it can generate a circulating flow. Of course, when a microorganism culturing agent having high extraction efficiency is used or when it is desired to perform extraction slowly, the extraction may be performed in a stationary state without installing the circulating flow generator.

Further, as shown in FIG. 2, when the stirring device 16 is provided inside the extraction tank main body 4, the extraction efficiency is further improved. As shown in FIG. 3, a stirrer is installed in the center of the hollow portion inside the donut-shaped cylinder 17 to generate a forced rotational flow in the solvent, so that the contact between the solvent and the microorganism culturing agent is efficiently performed. It can also be done.

The extract 18 obtained in the extraction tank 1 is transferred to the culture tank 2 through an extract inlet port 28 by an extract transfer pipe 3 to which a water flow pump 19 is connected. Reference numeral 20 denotes a culture tank main body formed in a cylindrical shape, and an inflow port 2 through which a culture liquid 21 such as sludge flows into an upper portion of the culture tank main body 20.
2. An overflow drain 23 for discharging excess culture liquid 21 to the outside of the culture tank 2 and a water level sensor 24 for regulating the flow rates of the culture liquid 21 and the extract 18 are provided. Is provided with an outlet 25 for taking out the generated activated sludge to the outside of the culture tank 2.

In order to adjust the inside of the culture tank 2 to an aerobic environment, an air diffuser 26 is mounted on the lower side of the culture tank 2. A stirrer 27 for uniformly circulating the culture solution 21 in the culture vessel main body 20 is attached to the lower center of the culture vessel 2. The culture tank 2 does not basically contain the microorganism culture agent 6, but may be appropriately charged with a microorganism culture agent when the production capacity of activated sludge is to be increased or when the production time is desired to be reduced.

Next, the operation of the apparatus for producing activated sludge of this embodiment will be described. In FIG. 1, a solvent 9 is caused to flow from a solvent inlet 10 into an extraction tank 1 by a pump (not shown) at a flow rate set by a water level sensor 12. When the solvent 9 in a specified amount or more flows into the extraction tank 1 due to malfunction of the water level sensor 12, an extra amount of the solvent 9 is discharged from the overflow drain 11 to the outside of the extraction tank 1. After a specified amount of the solvent 9 flows into the extraction tank 1, the circulating flow generator 13 is operated to bring the solvent 9 into contact with the microorganism culture agent 6 for a time set by a timer. The solvent 9 passes through the inside of the microbial culture medium 6 and the gap between the microbial culture medium 6, contacts the microbial culture medium 6, circulates while dissolving the active ingredient of the microbial culture medium 6, and generates the extract 18.

Next, a culture liquid 21 such as sludge is caused to flow into the culture tank 2 from the inflow port 22 by an amount not specified by the water level sensor 24 by a pump or the like (not shown). Water level sensor 2
When the culture medium 21 having a predetermined amount or more flows into the culture tank 2 due to the operation failure of Step 4, an excessive amount of the culture medium 21 is discharged out of the culture tank 2 from the overflow drain 23. After a specified amount of the culture solution 21 flows into the culture tank 2, the generated extract 18 is supplied to the culture tank 2 by the water flow pump 19 via the extract transfer pipe 3 by an amount specified by the water level sensor 24. Transfer. Also in this case, when the extract 18 in a specified amount or more flows in due to the malfunction of the water level sensor 24, an extra amount of the extract 18 is discharged from the overflow drain 23 to the outside of the culture tank 2.

After the specified amount of the extract 18 has been transferred to the culture tank 2, the amount of the extract transferred to the culture tank 2 is reduced in the extraction tank 1. The solvent 9 is newly replenished to the extraction tank 1 from 10, and the extraction is started again. Next, the culture solution 21 and the extract 18 are
In order to efficiently culture the mixed solution under the aerobic condition, the air diffuser 26 and the stirring device 27 are operated. Incubate for the time set by the timer to generate the desired activated sludge.

The generated activated sludge is taken out from the take-out port 25 to the outside of the culture tank 2 and used for purifying various organic wastewater. In this case, the amount of the activated sludge to be taken out is preferably about half the capacity of the culture tank 2 to leave seed sludge. The activated sludge reduced in the culture tank 2 is replenished by the liquid to be cultured 21 and the newly generated extract 18. This series of steps is repeated every time set by the timer.

The amount of the microbial culture agent 6 to be stored in the extraction tank 1 is appropriately adjusted depending on the type of the microbial culture agent 6. It is preferable to set the weight ratio of the tank 1 to about 1:50. Further, the extraction time and the culture time can be appropriately adjusted according to the microorganism culture agent 6 to be used. In particular, when a substance containing a humic substance is used as the microorganism culturing agent 6, it is preferable that both the extraction time and the culturing time be 24 hours or more. Of course, it is not necessary to make the extraction time and the culturing time the same, and when the culturing time is shorter than the extraction time, the number of culturing times: the number of culturing times can be appropriately set to 2: 1 or the like. The ratio between the amount of extract and the amount of sludge in the culture tank 2 is preferably set between 1:10 and 1: 1, but is not limited to this.

Further, in the embodiment described above, one kind of these processes has been described by the batch system, but may be a continuous system. That is, the solvent 9 is continuously flowed into the extraction tank 1, the extract liquid overflowing from the extraction tank 1 is continuously transferred to the culture tank 2, and the activated sludge overflowing from the culture tank 2 is continuously taken out. It can also be used to purify various organic wastewaters.

Next, FIG. 4 shows an example in which the activated sludge production apparatus of the present invention is installed in a wastewater treatment facility. The organic wastewater that has flowed into the wastewater treatment facility is separated into treated water and sludge in the sedimentation step via a screen, a sedimentation pond, and a reaction step for performing treatment with microorganisms and the like. Part of the treated water is taken into the extraction tank to be used as a solvent for the extract,
After the sludge is concentrated in the concentration step, a part of the sludge is taken into the culture tank to be used as a liquid to be cultured. The activated sludge activated and produced by the extract is returned to each treatment tank in the reaction step, and as a result, the concentration of the activated sludge is increased in all the steps, thereby increasing the treatment efficiency.

[0024]

As is apparent from the above description, according to the method and apparatus for producing activated sludge of the present invention, clogging of a microorganism culture agent, reduction of culture efficiency due to clogging, and consumption of the culture agent can be achieved. It can be as small as possible. Therefore, the present invention is extremely practical because it is possible to greatly reduce human resources, time, and the like having a cleaning operation and a replacement operation of a culture medium, which greatly contributes to simplification of maintenance and reduction of running costs. It is.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an apparatus for producing activated sludge, showing one embodiment of the apparatus of the present invention.

FIG. 2 is a longitudinal sectional view showing another example of the extraction tank in the apparatus of the present invention.

FIG. 3 is a vertical sectional view showing still another example of the extraction tank in the apparatus of the present invention.

FIG. 4 is a schematic diagram illustrating a case where the apparatus of the present invention is used in a wastewater treatment facility.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Extraction tank 2 ... Culture tank 3 ... Extract liquid transfer pipe 4 ... Extract liquid main body 5 ... Cylindrical body 6 ... Microorganism culture agent 7 ... Bottom plate 8 ... Top plate 9 ... Solvent 10 ... Inflow port 11 ... Overflow drain port 12 ... Water level sensor 13 ... Circulating flow generator 14 ... Circulating flow tube 15 ... Circulating flow tube 16 ... Stirring device 17 ... Doughnut type cylinder 18 ... Extracted liquid 19 ... Water flow pump 20 ... Culture tank body 21 ... Cultivated liquid 22 ... Inlet 23 ... overflow drain 24 ... water level sensor 25 ... outlet 26 ... diffuser 27 ... stirrer 28 ... extract liquid inlet

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-10-486 (JP, A) JP-A-10-487 (JP, A) JP-A-7-256269 (JP, A) JP-A-63- 156598 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C02F 3/12 C02F 3/00 C12N 1/00

Claims (11)

(57) [Claims] 1. A solvent for an extract is brought into contact with a microorganism culturing agent in an extraction tank to produce an extract, and the obtained extract is transferred to a culture tank, where it is mixed with a liquid to be cultured and subjected to aerobic conditions. A method for producing activated sludge, wherein the activated sludge is produced by culturing under activated sludge. 2. The microorganism culturing agent is a useful microorganism culturing agent in the form of a pellet, a substance containing far-infrared ceramics, rocks, minerals, humus, a substance having an antibacterial effect on microorganisms other than useful bacteria, or a mixture of these substances. The method for producing activated sludge according to claim 1, wherein 3. The method for producing activated sludge according to claim 1, wherein the solvent for the extract is water or organic wastewater or a mixture thereof. 4. The method for producing activated sludge according to claim 1, wherein the liquid to be cultured is sludge. 5. An extraction tank having an inlet for an extract solvent and an outlet for an extract and containing a microorganism culture agent therein, and an extract inlet connected to the extract outlet. An activated sludge producing apparatus, comprising: a culture tank having an inlet for a liquid to be cultured and an aeration device provided therein. 6. The activated sludge production apparatus according to claim 5, wherein a device for circulating the liquid in the extraction tank is attached to the extraction tank. 7. The activated sludge production apparatus according to claim 5, wherein a liquid stirring device is provided in the extraction tank. 8. The microbial culture medium is a useful microbial culture medium in the form of a pellet, a substance containing far-infrared ceramics, rocks, minerals, humus, a substance having an antibacterial effect on microorganisms other than useful microorganisms, or a mixture of these substances. The activated sludge production apparatus according to claim 5, wherein 9. The activated sludge production apparatus according to claim 5, wherein a liquid stirring device is provided inside the culture tank. 10. The activated sludge producing apparatus according to claim 5, wherein an outlet for taking out activated sludge is provided at the bottom of the culture tank. 11. The activated sludge production apparatus according to claim 5, wherein the extraction tank and the culture tank are connected by a transfer pipe via a pump.