JP4062892B2 - Drainage processing method and apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a drainage treatment method and apparatus by aerobic biological treatment of organic drainage, and particularly relates to a drainage treatment method and apparatus provided with sludge reduction means.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in order to reduce the volume of excess sludge in activated sludge treatment, a technique is known in which sludge is oxidized and decomposed by reacting ozone with biological sludge such as excess sludge (hereinafter sometimes simply referred to as sludge). In this method, sludge is reduced to be easily biodegradable by oxidative decomposition, and then the ozone-treated sludge is introduced into the aeration tank together with the liquid to be treated for aerobic biological treatment. it can.
In the ozone treatment, a sludge-containing liquid is introduced into a reaction tank, an ozone-containing gas is blown into the sludge-containing liquid and brought into gas-liquid contact, and a sludge is decomposed. In such an ozone treatment apparatus, when ozone treatment is performed by blowing ozone-containing gas into the sludge-containing liquid, the ozone treatment sludge foams and bubbles are taken out of the tank, and the surroundings are contaminated. Sometimes.
[0003]
As an apparatus for coping with such a problem of foaming of the ozone treatment liquid, Japanese Patent Application Laid-Open No. 8-267099 has separated an ozone treatment tank for performing sludge ozone treatment, and a gas-liquid separation apparatus for performing gas-liquid separation. An ozone treatment device is disclosed that includes a storage tank that stores ozone-treated sludge and an ozone removal device that removes ozone from exhausted ozone gas, and the lower part of the gas-liquid separator is sealed with the liquid in the tank of the storage tank. Yes.
In this apparatus, foaming can be positively used to increase the ozone treatment efficiency, and foam can be prevented from being taken out of the tank. In such an ozone treatment apparatus, when the gas-liquid separator is provided in the upper part of the drainage tank or the aeration tank and used in a liquid-sealed state, it is not necessary to transfer the separated sludge.
[0004]
However, when the separated ozone-treated sludge is supplied to the aeration tank, foaming occurs with the aeration, so it is necessary to take measures such as spraying an antifoaming agent to eliminate the bubbles. The addition of the antifoaming agent not only increases the operating cost, but also causes a decrease in the oxygen dissolution efficiency of the aeration tank. Further, depending on the flow rate of the defoaming spray, the increase in the amount of water introduced into the aeration tank increases the water area load of the precipitation tank provided next to the aeration tank, which may adversely affect solid-liquid separation.
[0005]
[Problems to be solved by the invention]
An object of the present invention is to efficiently separate gas-liquid mixture of ozone-treated sludge and waste ozone gas at low cost and supply ozone-treated sludge to an aeration tank, and stably treat ozone-treated sludge. It is an object of the present invention to provide a drainage treatment method and apparatus that can be used.
[0006]
[Means for Solving the Problems]
  The present invention provides the following drainage treatment method and drainage treatment apparatus.
  (1) an aerobic treatment step in which an organic waste liquid supplied from a drainage tank is aerated in the presence of activated sludge in an aeration tank;
  An ozone treatment process for treating the sludge extracted from the aerobic treatment process with ozone;
  Gas-liquid separation of the gas-liquid mixture of the ozone-treated sludge obtained in the ozone treatment step and the exhausted ozone gas, and the gas-liquid separation step of supplying the separated sludge to the drainage tank and / or the aeration tank,
  In the gas-liquid separation process, A separation tower that separates ozone-treated sludge in the gas-liquid mixture into the aeration tank or drainage tank connected to the aeration tank by its own weight and separates it from the exhaust ozone gas, and the lower part is in the tank of the aeration tank or the drainage tank Using a plurality of gas-liquid separators having a separation tower sealed with liquid and an exhaust gas path for discharging the separated exhaust ozone gas,Gas-liquid mixtureSpecific amount every predetermined timeSplitting into gas-liquid separatorSwitch toThe wastewater treatment method in which the separated liquid sludge is supplied to different positions along the flow of the liquid in the drainage tank and / or the aeration tank.
  (2)  The gas-liquid separation step is performed by the gas-liquid separation device provided in the upper part of the drainage tank and / or the upper part of the aeration tank.(1) NotesThe drainage treatment method listed.
  (3)  An aerobic treatment system for aerobic treatment by aeration of organic waste liquid supplied from the drainage tank in the presence of activated sludge in the aeration tank;
  An ozone treatment device for ozone treatment of sludge extracted from the aerobic treatment system;
  Gas-liquid mixture of ozone-treated sludge and waste ozone gas obtained with an ozone treatment deviceThe total amount of water is stored in a specific gas-liquid separator every predetermined time.DivertTo switchA shunt device;
  A plurality of gas-liquid separation devices for separating each gas-liquid mixture divided by the flow dividing device and supplying separated sludge to different positions along the flow of the liquid in the drainage tank and / or the aeration tank; IncludingSee
  A gas-liquid separator is a separation tower that drops ozone-treated sludge in a gas-liquid mixture into its aeration tank or drainage tank connected to the aeration tank by its own weight and separates it from exhaust ozone gas. It has a separation tower sealed with liquid in the tank of the liquid tank, and an exhaust gas path for discharging the separated exhaust ozone gasDrainage treatment device.
  (4)  The gas-liquid separation device is provided above the drainage tank and / or the aeration tank(3) NotesMounted drainage treatment equipment.
  (5)  The gas-liquid separators are provided at a distance of 5 m or more from each other.(3) or (4)The drainage processing apparatus as described.
[0007]
The drainage treatment method of the present invention aerobically treats the organic drainage supplied from the drainage tank in the aerobic treatment step by aeration in the presence of activated sludge in the aeration tank, and aerobic treatment in the ozone treatment step. The sludge extracted from the process is treated with ozone, and the gas-liquid mixture of the ozone-treated sludge and exhaust ozone gas obtained in the ozone treatment process is gas-liquid separated in the gas-liquid separation process, and the separated sludge is drained and / or aerated. To supply. In this gas-liquid separation step, the gas-liquid mixture is divided into a plurality of gas-liquid separators for gas-liquid separation, and each separated sludge is different from each other along the flow of the liquid in the drainage tank and / or the aeration tank. Feed position.
[0008]
As a drainage treatment apparatus that can be employed in such a drainage treatment method, the organic drainage supplied from the drainage tank in the aerobic treatment system is preferably aerated in the presence of activated sludge in the aeration tank. The sludge extracted from the aerobic treatment system in the ozone treatment device is subjected to ozone treatment, and the gas-liquid mixture of the ozone treatment sludge obtained from the ozone treatment device and the exhaust ozone gas is separated by the flow dividing device, and a plurality of gas liquids are separated. Drainage that separates each gas-liquid mixture diverted by the diversion device in the separation device and supplies the separated sludge to different positions along the flow of the liquid in the drainage tank and / or the aeration tank A processing apparatus is mentioned. The sludge volume can be efficiently reduced by the treatment using this apparatus.
[0009]
In the aerobic treatment step, the organic drainage supplied from the drainage tank is aerobically treated by aeration in the presence of activated sludge in the aeration tank.
The organic waste liquid introduced into the aeration tank and aerated is a waste liquid containing an organic substance, such as factory waste liquid or human waste. Activated sludge is held in the aeration tank, and the organic waste liquid introduced into the aeration tank is aerobically treated and decomposed by microorganisms in the activated sludge while being aerated. Organic drainage is introduced into the aeration tank via the drainage tank. The aeration tank here can include a re-aeration tank of return sludge and other secondary aeration tanks. Moreover, a partition can be provided in an aeration tank, and a some compartment can be formed in an aeration tank. The partition wall can be provided in any shape such as at the upper part or lower part of the aeration tank so that a part of the liquid in the tank can flow into the next continuous compartment. When a partition is provided, the liquid in a tank is discharged | emitted through each fractionation chamber toward the discharge side of a treated water from the supply side of raw | natural water.
[0010]
Part of the sludge from the aerobic treatment process is extracted and sent to the ozone treatment process. In the ozone treatment, the sludge is decomposed by bringing the ozone-containing gas into contact with the sludge. The sludge to be treated with ozone is preferably composed mainly of biological sludge such as surplus sludge, but may contain some inorganic substances such as coagulated sludge. In the ozone treatment, the foaming can be suppressed and the ozone treatment can be performed, or the foaming can be positively performed and the ozone treatment can be performed. In the ozone treatment, the sludge extracted from the aeration tank can be once introduced into the solid-liquid separation device for solid-liquid separation, and a part of the separated sludge can be treated with ozone.
[0011]
Examples of the ozone-containing gas used in the ozone treatment include ozone-containing air and ozonated oxygen. The amount of ozone introduced is desirably 0.5 to 10%, preferably 1 to 5% with respect to the VSS weight of the biological sludge to be introduced. The flow rate of the ozone-containing gas is 5 to 50 m / hr, preferably 10 to 30 m / hr, as the gas linear velocity of the reaction tank.
[0012]
The gas-liquid mixture in which the ozone-treated sludge obtained from the ozone treatment step and the exhaust ozone gas are mixed is divided by the flow dividing device. The diversion device can be configured such that, for example, the gas-liquid mixture supply path extending from the ozone treatment tank branches into two or more, and the branched supply paths communicate with different gas-liquid separators. The gas-liquid mixture divided by the flow dividing device is sent to the gas-liquid separation step, and is separated by the gas-liquid separation device.
[0013]
  It is preferable that an introduction amount adjusting valve for adjusting the introduction amount is provided in each branched supply path of the flow dividing device. The introduction amount adjusting valve is a valve that adjusts the inflow amount of the gas-liquid mixture into the gas-liquid separator. By providing the introduction amount adjusting valve, the flow rate of the gas-liquid mixture separated in each gas-liquid separation device can be adjusted.in this case,Multiple gas-liquid separators for the total amount of gas-liquid mixtureOf particular gas-liquid separatorIt is possible to control the introduction amount adjusting valve so that the flow is switched at predetermined intervals.At this timeControl the introduction amount control valve while monitoring the foaming condition in the aeration tank.Butit can.
[0014]
Specifically, the gas-liquid mixture to be gas-liquid separated by the gas-liquid separator is ozone-treated sludge containing exhausted ozone gas bubbles, bubbles in which the ozone-treated sludge is foamed, exhausted ozone gas accompanied by foam, a mixture thereof, and the like. Then, the ozone-treated sludge is separated from such a mixture and introduced into the drainage tank and / or the aeration tank. The exhaust ozone gas separated from the ozone treatment sludge by the gas-liquid separator is discharged and processed. The ozone-treated sludge introduced into the drainage tank is sent to the aeration tank together with the organic waste liquid, and the ozone-treated sludge introduced directly into the aeration tank is mixed with the organic waste liquid in the aeration tank and aerated. The
[0015]
  The gas-liquid separator is preferably provided in the upper part of the drainage tank and / or the upper part of the aeration tank. AlsoThe gas-liquid separator isA separation tower that separates ozone-treated sludge in the gas-liquid mixture into the aeration tank or drainage tank connected to the aeration tank by its own weight and separates it from the exhaust ozone gas, and the lower part is the liquid in the tank of the aeration tank or drainage tank A separation tower sealed with liquid and an exhaust gas path for discharging the separated exhaust ozone gasConfigure as.
[0016]
  Gas-liquid separatorThenThe separation tower receives a gas-liquid mixture of ozone-treated sludge and exhausted ozone gas, drops the ozone-treated sludge into the aeration tank or drainage tank by its own weight, and obtains ozone-treated sludge as separated sludge and exhausted ozone gas as separated gas . Ozone-treated sludge that has fallen due to its own weight comes into contact with the liquid in the tank at the liquid level of the aeration tank or drainage tank, is diluted, and diffuses throughout the tank. When the gas-liquid mixture is continuously introduced into the separation tower, an ozone-treated sludge layer may be formed on the upper part of the liquid surface, which may increase the height, but if the amount of ozone-treated sludge increases, it will be pushed by its own weight. Then, it diffuses into the liquid in the tank and the height decreases. On the other hand, the separated exhaust ozone gas is discharged from an exhaust gas passage provided in the upper part of the separation tower.
[0017]
The gas-liquid mixture is introduced from the liquid sealing surface of the liquid in the tank to the upper end of the separation tower, that is, in the middle part, but at a position 50 cm or higher, preferably 100 to 150 cm higher than the liquid sealing water surface, and the upper end of the separation tower To 50 cm or more, preferably 100 to 150 cm lower. When introduced at such a position, it is possible to efficiently perform gas-liquid separation by dropping its own weight and to prevent the ozone-treated sludge from leaking out of the tower from the exhaust gas passage.
[0018]
Each gas-liquid separator is provided so that the separated sludge is supplied to different positions along the flow of the liquid in the drainage tank and / or the aeration tank. That is, it is only necessary to be spaced from each other with respect to the flow direction of the liquid in the tank (the direction from the waste liquid supply side to the treatment liquid discharge side), for example, the upstream part of the aeration tank, the midstream part, It can be provided in the downstream portion or the like. In this case, the interval between the gas-liquid separators is preferably 5 m or more, more preferably 10 m or more. Thus, by providing the gas-liquid separators at an interval, it is possible to prevent a large amount of ozone-treated sludge from being introduced at one location of the aeration tank and excessive foaming.
[0019]
All of the gas-liquid separator can be installed in the upper part of the aeration tank. All of the gas-liquid separator can be provided in the upper part of the drainage tank, but in order to effectively prevent foaming, it is preferably installed in both the upper part of the drainage tank and the upper part of the aeration tank.
[0020]
When providing in the upper part of an aeration tank, when a partition is provided in an aeration tank and a plurality of fractionation rooms are formed, it is preferred to provide at least one gas-liquid separation device in the upper part of each fractionation room. In this case, it is not necessary to provide a gas-liquid separation device in the upper part of all the fractionation chambers, and it is preferable to provide them in at least two or more fractionation chambers. In this way, the inside of the aeration tank is partitioned by the partition walls, and the ozonized sludge can be introduced into each fractionation chamber by providing the gas-liquid separation device above each partitioned compartment. Therefore, ozone treatment sludge containing exhaust ozone gas is not concentrated and introduced in one place of the aeration tank, and foaming can be reliably suppressed. In addition, when providing a gas-liquid separator in the upper part of each compartment, the space | interval between gas-liquid separators may be 5 m or less.
Furthermore, in this case, it is preferable to control the introduction amount adjusting valve so that the gas-liquid mixture is sequentially introduced into any one of the plurality of gas-liquid separators, since foaming can be prevented more reliably.
[0021]
When the gas-liquid separator is installed in the aeration tank, it is preferable to install it at a point where the rise of the aerated air is small in order to prevent the aerated air from entering the separation tower. Further, a baffle plate can be provided at the lower end of the separation tower to prevent aeration air from entering. When installing in a swirling flow aeration tank, installing a separation tower at a point with downward water flow further improves the efficiency of dilution and diffusion, further improving the efficiency of gas-liquid separation, and lowering the cost. Can be processed.
[0022]
Exhaust ozone gas separated by the gas-liquid separator is preferably subjected to ozone removal treatment. For example, the waste ozone gas can be treated by connecting an exhaust gas path to the waste ozone removal device. Examples of the exhaust ozone removal device include a device in which a packed bed filled with an ozone removal agent such as activated carbon or a catalyst is formed.
[0023]
In the present invention, the gas-liquid mixture is diverted by the diverter, and each of the diverted gas-liquid mixtures is introduced into a plurality of gas-liquid separators for processing. Foaming can be suppressed without providing a defoaming means such as. However, even in the event that a gas-liquid separation device malfunctions and bubbles and foam leak out of the separation tower, a defoaming means such as a spray nozzle for spraying defoaming water or antifoaming agent may be provided in the separation tower. Good.
[0024]
The ozone-treated sludge separated from the gas-liquid separator is mixed with activated sludge in the aeration tank together with the organic waste liquid supplied from the drainage tank and aerated for aerobic biological treatment, and easily biodegradable by ozone. The organic matter converted into is decomposed. By introducing ozone-treated sludge directly into the aeration tank from the gas-liquid separator or via the drainage tank, and introducing aerobic treatment by introducing the organic drainage liquid into the aeration tank, these ozone-treated sludge and organic Organic matter in the effluent is biologically degraded. Thereby, volume reduction of sludge can be achieved.
[0025]
In the present invention, in the aerobic treatment system, the mixed sludge in the aeration tank is sent to the solid-liquid separation device for solid-liquid separation, and a part of the obtained separated sludge is returned to the aeration tank, and a part thereof is treated with ozone. It is preferable to apply to a standard activated sludge method in which the gas-liquid mixture obtained is sent to a tank, treated with ozone, and introduced into a gas-liquid separator. However, the present invention is not limited to such a drainage treatment method. For example, sludge taken out from an aeration tank may be directly introduced into an ozone treatment tank without performing a solid-liquid separation device, and may be subjected to ozone treatment.
[0026]
【The invention's effect】
  The drainage treatment method of the present invention provides gas-liquid separation of a gas-liquid mixture.To a specific gas-liquid separator every predetermined timeDiversionSwitch to have a specific configurationThe gas-liquid separators are installed at different positions along the flow of the liquid in the tank.TheOzone-treated sludge separated from gas-liquid mixture is introduced into different parts of drainage tank and / or aeration tankBecause I didFurther, the foaming caused by the ozone-treated sludge can be suppressed, and the ozone-treated sludge can be stably biologically treated. Therefore, the waste liquid can be aerobically treated efficiently at low cost.
[0027]
  The drainage treatment apparatus of the present invention is a gas-liquid mixture using a diversion device.Switch the total amount of gas to a specific gas-liquid separator every predetermined timeDivert the diverted gas-liquid mixtureHave a specific configurationGas-liquid separation can be performed by a plurality of gas-liquid separators. These gas-liquid separators are provided at different positions along the flow of the liquid in the tank, and the ozone-treated sludge separated from the gas-liquid mixture is discharged from the drain tank and / or Or can be introduced at different locations in the aeration tankBecause I didIn addition, the ozone-treated sludge can be prevented from foaming, and the ozone-treated sludge can be stably biologically treated. Therefore, the waste liquid can be efficiently aerobically treated at low cost.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a system diagram showing a drainage treatment system using the drainage treatment apparatus of the present invention. In FIG. 1, 1 is a drainage treatment apparatus, 2a and 2b are gas-liquid separation apparatuses, 10 is an aeration tank, 14 is a drainage tank, 20 is a solid-liquid separation tank, and 30 is an ozone treatment tank.
[0029]
In the drainage treatment system shown in FIG. 1, the liquid collection path 14 a communicates with the drainage tank 14, and the raw water path 15 extending from the drainage tank 14 communicates with the aeration tank 10. A communication path 16 extends from the aeration tank 10 to communicate with the solid-liquid separation tank 20. In the aeration tank 10, partition walls 11a and 11b are provided, and a first fractionation chamber 10a, a second fractionation chamber 10b, and a third fractionation chamber 10c are formed. A first gas-liquid separator 2a is provided above the first fraction chamber 10a, and a second gas-liquid separator 2b is provided above the second fraction chamber 10b. The first and second gas-liquid separators 2a and 2b are in communication with gas-liquid mixture introduction paths 3a and 3b of the flow dividing device. An ozone treatment sludge transfer path 25 extending from the ozone treatment tank 30 is branched and communicated with the gas-liquid mixture introduction paths 3a and 3b. The gas-liquid mixture introduction paths 3a and 3b are provided with introduction amount control valves 4a and 4b.
[0030]
The treated water is taken out from the treated water channel 21 extending from the solid-liquid separation tank 20. On the other hand, the separated sludge is taken out from the sludge discharge path 22 extending from the solid-liquid separation tank 20. The sludge discharge passage 22 communicates with the extraction sludge passage 24, and the withdrawal sludge passage 24 communicates with the ozone treatment tank 30 through the pump 23. The sludge discharge path 22 also communicates with the return sludge path 17, and the return sludge path 17 communicates with the first fractionation chamber 10 a of the aeration tank 10.
[0031]
The first gas-liquid separation device 2a is configured to introduce a gas-liquid mixture located at an intermediate portion between the separation tower 6a communicated by the gas-liquid mixture introduction path 3a of the flow dividing device and the liquid sealing water surface of the aeration tank 10 and the upper end of the separation tower 6a. The outlet 7a and an exhaust gas passage 9a extending from the upper end of the separation tower 6a are configured.
[0032]
In the first fractionation chamber 10 a, the lower end of the separation tower 6 a of the first gas-liquid separation device 2 a is installed in a state sealed with the liquid in the tank of the aeration tank 10. A baffle plate 8a is provided at the lower end of the separation tower 6a so as to prevent aeration air from entering. The separation tower 6a is installed at a point where there is a water flow in which the liquid in the tank flows downward.
[0033]
Similar to the first gas-liquid separator 2 a, the second gas-liquid separator 2 b is provided in the upper part of the second fractionation chamber 10 b of the aeration tank 10. The second gas-liquid separator 2b has the same configuration as the first gas-liquid separator 2a.
[0034]
A gas-liquid mixture of ozone-treated sludge and waste ozone gas generated by ozone treatment of the biological sludge-containing liquid passes through the first gas-liquid mixture introduction path 3a to the first gas-liquid separation device 2a and also to the second It is sent to the second gas-liquid separator 2b through the gas-liquid mixture introduction path 3b. The first gas-liquid mixture introduction path 3a is provided with the first introduction amount adjustment valve 4a, and the second gas-liquid mixture introduction path 3b is provided with the second introduction amount adjustment valve 4b. The flow rate of the gas-liquid mixture can be controlled by opening and closing the valves 4a and 4b.
[0035]
In order to gas-liquid separate the gas-liquid mixture of ozone-treated sludge and exhaust ozone gas in the first gas-liquid separator 2a, the gas-liquid mixture is continuously introduced into the separation tower 6a from the gas-liquid mixture inlet 7a, To drop. The ozone-treated sludge that has fallen due to its own weight comes into contact with the liquid in the tank at the liquid surface portion of the first fractionation chamber 10a, is diluted, and diffuses throughout the tank. In this case, a baffle plate 8a is provided at the lower end of the separation tower 6a so as to prevent aeration air from entering, and since the separation tower 6a is installed at a point where there is a downward water flow, diffusion proceeds efficiently. . When the gas-liquid mixture is continuously introduced into the separation tower 6a, an ozone-treated sludge layer may be formed on the upper surface of the liquid surface, which may increase the height. However, when the amount of ozone-treated sludge increases, It is pushed and diffuses into the liquid in the tank and the height decreases. On the other hand, the separated exhaust ozone gas is discharged from the exhaust gas passage 9a.
[0036]
The ozone-treated sludge separated by the first gas-liquid separator 2a is the raw water introduced from the raw water channel 15 in the first fractionation chamber 10a of the aeration tank 10, and the activated sludge in the first fractionation chamber 10a. The air is mixed with the return sludge returned from the return sludge passage 17, and the air supplied from the air supply passage 13 is diffused from the aeration device 12 to be subjected to aerobic biological treatment. At this time, the ozone-treated sludge dropped from the first gas-liquid separator 2a is quickly diluted and diffused with the liquid in the tank in the first fractionation chamber 10a and decomposed. This processing liquid is introduced into the second fractionation chamber 10b of the aeration tank 10 through the lower part of the partition wall 11a.
[0037]
The ozone-treated sludge separated by the second gas-liquid separator 2b is mixed with the sludge introduced from the first fractionation chamber 10a and the activated sludge in the second fractionation chamber 10b in the aeration tank 10, Air supplied from the air supply path 13 is diffused from the aeration device 12 and aerobic biological treatment is performed. Similarly to the first fractionation chamber 10a, the ozone-treated sludge that has fallen from the second gas-liquid separator 2b is quickly diluted and diffused with the liquid in the tank in the second fractionation chamber 10b and decomposed. The processing liquid is taken out from the communication path 16 through the third fractionation chamber 10c.
[0038]
The first and second gas-liquid separators 2a and 2b are introduced with the gas-liquid mixture divided by the introduction amount control valves 4a and 4b provided in the gas-liquid mixture introduction paths 3a and 3b. The introduction amount adjusting valves 4a and 4b can reliably adjust the introduction amount of the gas-liquid mixture to be gas-liquid separated in the first and second gas-liquid separation devices 2a and 2b. In the drainage treatment apparatus 1, while the first introduction amount adjustment valve 4a is opened, the second introduction amount adjustment valve 4b is closed and the gas-liquid mixture is introduced only into the first gas-liquid separation device 2a. To do. After a predetermined amount of the gas-liquid mixture has been introduced into the first gas-liquid separator 2a, this time, the first introduction amount adjustment valve 4a is closed, the second introduction amount adjustment valve 4b is opened, and the gas-liquid mixture is opened. Is controlled to be introduced into the second gas-liquid separator 2b. In this way, the opening / closing of the introduction amount adjusting valves 4a, 4b is controlled for each predetermined time so that a predetermined amount of the gas-liquid mixture is alternately introduced into one of the first and second gas-liquid separators 2a, 2b. Then, even if foaming occurs in the aeration tank 10, excessive foaming in the aeration tank 10 can be suppressed by switching the supply destination of the ozone-treated sludge to the other compartment before foaming becomes excessive. It is also possible to introduce the gas-liquid mixture equally into the first and second gas-liquid separators 2a and 2b.
[0039]
As described above, in the drainage treatment apparatus 1, the gas-liquid mixture can be divided and introduced into the gas-liquid separators 2a and 2b by controlling the introduction amount control valves 4a and 4b, so that the gas-liquid separation is stabilized. Can be done. As a result, the amount of foaming in the aeration tank 10 can be suppressed, and biological treatment of the aeration tank 10 can be performed efficiently and stably. In addition, it is not necessary to use antifoaming water or antifoaming agents that have been used in conventional aeration tanks, and even if it is used, a small amount is sufficient, so low-cost processing is possible. is there.
[0040]
The sludge aerated in the aeration tank 10 as described above is introduced into the solid-liquid separation tank 20 part by part through the communication path 16 extending from the aeration tank 10. In the solid-liquid separation tank 20, the separated water and the separated sludge are separated by precipitation, and the separated water is discharged from the treated water channel 21 as treated water. On the other hand, the separated sludge is taken out from a sludge discharge path 22 extending from the lower part of the solid-liquid separation tank 20. Part of the extracted sludge passes through the return sludge passage 17 branched from the sludge discharge passage 22 and is introduced into the aeration tank 10 as return sludge. In addition, when excess sludge arises, it is discharged | emitted from the excess sludge discharge path 28. FIG.
[0041]
A part of the sludge separated in the solid-liquid separation tank 20 is introduced into the ozone treatment tank 30 by the pump 23 through the drawn sludge path 24 branched from the sludge discharge path 22 as drawn sludge. Ozone generated by the ozone generator 31 is supplied from the ozone supply path 32 to the lower part of the ozone treatment tank 30 and is contacted with the extracted sludge to perform ozone treatment. As a result, the sludge in the extracted sludge is converted into readily biodegradable organic matter.
[0042]
The ozone-treated sludge is introduced into the first and second gas-liquid separators 2a and 2b from the ozone-treated sludge transfer path 25 in a state where exhaust ozone gas is mixed, and gas-liquid separation is performed. In this case, the ozone-treated sludge can be transferred to the gas-liquid separators 2a and 2b by the ozone supply pressure introduced into the ozone treatment tank 30, so that a transfer pump or the like is not required and can be processed at low cost. is there. There is no malfunction of the pump due to gas. The gas-liquid separated ozone-treated sludge is subjected to the aerobic biological treatment in the aeration tank 10 as described above, and the organic matter converted to easily biodegradable is decomposed together with the organic matter of the raw water.
[0043]
FIG. 2 is a system diagram showing a drainage treatment system using a drainage treatment apparatus according to another embodiment of the present invention.
The drainage treatment apparatus 1A of FIG. 2 is shown in FIG. 1 in that the first gas-liquid separator 2a is provided at the upper part of the drainage tank 14, and the second gas-liquid separator 2b is provided at the upper part of the aeration tank 10. Different from the drainage treatment apparatus 1.
[0044]
In the drainage treatment apparatus 1A, the first gas-liquid separation device 2a is provided above the drainage tank 14, and a part of the gas-liquid mixture supplied from the ozone treatment tank 30 passes through the ozone treatment sludge transfer path 25. Then, the gas is further introduced into the first gas-liquid separator 2a through the gas-liquid mixture introduction path 3a branched from the ozone treatment sludge transfer path 25. The ozone-treated sludge that has been gas-liquid separated by the first gas-liquid separation device 2 a is introduced into the drainage tank 14. The ozone-treated sludge introduced into the drainage tank 14 is mixed with the organic drainage liquid in the drainage tank 14 and introduced into the aeration tank 10 through the raw water channel 15.
[0045]
Further, the remaining part of the gas-liquid mixture supplied from the ozone treatment tank 30 passes through the ozone-treated sludge transfer path 25, and further passes through the gas-liquid mixture introduction path 3 b branched from the ozone-treated sludge transfer path 25. It is introduced into the gas-liquid separator 2b. The ozone-treated sludge that has been gas-liquid separated by the second gas-liquid separator 2 b is introduced into the aeration tank 10.
[0046]
In the aeration tank 10, the ozone treatment sludge separated by the second gas-liquid separation device 2b provided in the upper part thereof, the mixture of the organic drainage and ozone treatment sludge supplied from the raw water channel 15, and the return sludge passage The return sludge supplied from 17 and the activated sludge in the aeration tank 10 are mixed and aerated. The treated water is sent to the solid-liquid separation tank 20 and treated in the same manner as in the drainage treatment system shown in FIG.
[0047]
In the drainage treatment apparatus 1A, since a part of the gas-liquid mixture is supplied to the drainage tank 14 by controlling the introduction amount control valves 4a and 4b, the ozone treatment sludge does not concentrate on the aeration tank 10, Foaming in the aeration tank 10 can be suppressed. The control of the introduction amount adjusting valves 4a and 4b of the first and second gas-liquid separators 2a and 2b may be any type. For example, the gas-liquid mixture may be introduced into one of the first and second gas-liquid separators 2a and 2b in order as in the embodiment shown in FIG. Or you may control so that a gas-liquid mixture may be equally introduce | transduced into 1st and 2nd gas-liquid separation apparatus 2a, 2b. In addition, while monitoring the amount of foaming in the aeration tank 10, when the amount of foaming in either the drainage tank 14 or the aeration tank 10 increases, the gas introduced into the gas-liquid separation device provided in the other tank It is possible to adjust appropriately such as increasing the amount of the liquid mixture.
[0048]
The present invention is not limited to the above embodiment. For example, in the drainage treatment system of FIG. 1 and FIG. 2, the solid-liquid separation tank 20 is provided to treat the separated sludge with ozone. In these embodiments, the sludge discharged from the aeration tank 10 is directly treated with the ozone treatment tank 30. It may be introduced into the ozone treatment. In this case, the solid-liquid separation tank 20 may or may not be provided. In addition to the aeration tank 10, even if a re-aeration tank is provided on the return sludge passage 17, and one or a plurality of gas-liquid separation devices are installed in the re-aeration tank, the same effect as that obtained in the above embodiment is obtained. Can be obtained.
[0049]
【Example】
Comparative Example 1
Drainage treatment facility (raw water flow rate 123m) as shown in Fig. 2 for organic wastewater of petrochemical factory^Three/ Hr, COD_CrLoad 1.87Kg / m^Three/ Day) However, in the aeration tank, the volume of each compartment is 250 m from the upstream side.^Three500m^Three750m^Three750m^ThreeThe four waste compartments separated by three partition walls so as to be prepared were prepared as a drainage treatment facility arranged in series. This drainage treatment facility is not provided with a gas-liquid mixture diversion device, and the gas-liquid mixture introduction path is not provided with an introduction amount adjusting valve. That is, only one gas-liquid separator is provided in the drainage tank, and no gas-liquid separator is provided in the aeration tank.
When treatment was started in this drainage treatment facility, immediately after the introduction of the ozone treatment sludge, foaming on the liquid surface in the tank in the first and second stage compartments of the aeration tank became stronger and the first stage fraction was removed. Bubbles rose to the top of the room. Therefore, in order to continue the treatment, it was necessary to add 5 ppm of the defoaming agent per raw water (drainage) and to spray the defoaming working water constantly into the first-stage fractionation chamber.
[0050]
Example 1
Wastewater treatment equipment (raw water flow rate 123m) as shown in Fig. 1 for organic wastewater at a petrochemical factory^Three/ Hr, COD_CrLoad 1.87Kg / m^Three/ Day) However, in the aeration tank, the volume of each compartment is 250 m from the upstream side.^Three500m^Three750m^Three750m^ThreeThe four waste compartments separated by three partition walls so as to be prepared were prepared as a drainage treatment facility arranged in series. In this drainage treatment facility, a first gas-liquid separation device is provided in the second-stage fractionation chamber, and a second gas-liquid separation device is provided in the third-stage fractionation chamber. However, no introduction amount control valve is provided.
When the treatment was started in this drainage treatment facility, since the introduction amount control valve was not provided, the ozone treatment sludge flowed to the first gas-liquid separator connected to the second-stage fractionation chamber. For this reason, although considerable foaming occurred in the second-stage fractionation chamber, only the addition of an antifoaming agent was required, and spraying of defoaming industrial water was unnecessary.
[0051]
Example 2
In the waste liquid treatment facility of the first embodiment, a gas-liquid separation device is provided in which gas-liquid mixture introduction paths 3a, 3b are provided with introduction amount control valves 4a, 4b as shown in FIG. The processing was performed in the same manner as in Example 1 while controlling the introduction amount adjusting valves 4a and 4b so that the gas-liquid mixture was alternately introduced into 2a and the second gas-liquid separator 2b. In the control of the introduction amount adjusting valve, 5 m of the gas-liquid mixture is placed in one gas-liquid separator.^ThreeAfter the introduction, the operation of introducing the same amount of gas-liquid mixture was repeated by closing the introduction amount control valve of the gas-liquid separation device and opening the introduction amount control valve of the other gas-liquid separation device ( Alternatively, the introduction amount control valve was opened and closed every 0.5 hour). As a result, the gas-liquid mixture was also introduced into the second gas-liquid separation device connected to the third-stage compartment, and excessive foaming in the second-stage compartment was drastically reduced. Therefore, there was no obstacle associated with foaming, and there was no need to spray an antifoaming agent or industrial water as in Comparative Example 1.
[Brief description of the drawings]
FIG. 1 is a system diagram showing a drainage treatment system using a drainage treatment apparatus of an embodiment.
FIG. 2 is a system diagram showing a drainage treatment system using a drainage treatment apparatus according to another embodiment.
[Explanation of symbols]
1 Wastewater treatment equipment
2a First gas-liquid separator
2b Second gas-liquid separator
3a, 3b Gas-liquid mixture introduction path
4a First introduction amount adjustment valve
4b Second introduction amount adjustment valve
6a, 6b Separation tower
7a, 7b Gas-liquid mixture introduction path
8a, 8b baffle plate
9a, 9b Exhaust gas passage
10 Aeration tank
10a First compartment
10b Second compartment
11a, 11b Bulkhead
12 Air diffuser
13 Air supply path
14 Drainage tank
14a Collection channel
15 Raw waterway
16 connection
20 Solid-liquid separation tank
21 treatment channel
22 Sludge discharge channel
23 Pump
24 Extracted sludge path
25 Ozone-treated sludge transfer path
28 Excess sludge discharge channel
30 Ozone treatment tank
31 Ozone generator
32 Ozone supply path

Claims (5)

An aerobic treatment step in which the organic drainage supplied from the drainage tank is aerated in the presence of activated sludge in the aeration tank;
An ozone treatment process for treating the sludge extracted from the aerobic treatment process with ozone;
Gas-liquid separation of the gas-liquid mixture of the ozone-treated sludge obtained in the ozone treatment step and the exhausted ozone gas, and the gas-liquid separation step of supplying the separated sludge to the drainage tank and / or the aeration tank,
In the gas-liquid separation process, the ozone-treated sludge in the gas-liquid mixture is dropped into the aeration tank or the drainage tank connected to the aeration tank by its own weight and separated from the exhausted ozone gas. Using a plurality of gas-liquid separators having a separation tower sealed with the liquid in the tank of the liquid tank and an exhaust gas passage for discharging the separated exhaust ozone gas, the total amount of the gas-liquid mixture is specified every predetermined time. Liquid-liquid separation by switching to gas-liquid separation device to separate the gas and liquid, and supplying each separated sludge to different positions along the liquid flow in the liquid drainage tank and / or aeration tank Method. Gas-liquid separation step, drainage processing method according to claim 1 Symbol placement performed by the drainage tank top and / or aeration tank gas-liquid separator provided in the upper part. An aerobic treatment system for aerobic treatment by aeration of organic waste liquid supplied from the drainage tank in the presence of activated sludge in the aeration tank;
An ozone treatment device for ozone treatment of sludge extracted from the aerobic treatment system;
A flow dividing device that switches the total amount of the gas-liquid mixture of the ozone-treated sludge and the exhaust ozone gas obtained by the ozone treatment device to a specific gas-liquid separation device every predetermined time ;
A plurality of gas-liquid separation devices for separating each gas-liquid mixture separated by the flow dividing device and supplying separated sludge to different positions along the flow of the liquid in the drainage tank and / or the aeration tank; only including,
The gas-liquid separator is a separation tower that drops ozone-treated sludge in a gas-liquid mixture into its aeration tank or drainage tank connected to the aeration tank by its own weight and separates it from exhaust ozone gas. A waste liquid treatment apparatus having a separation tower sealed with a liquid in a liquid tank and an exhaust gas passage for discharging the separated exhaust ozone gas . The drainage treatment apparatus according to claim 3 , wherein a gas-liquid separation device is provided in the upper part of the drainage tank and / or the upper part of the aeration tank. The drainage treatment apparatus according to claim 3 or 4 , wherein the gas-liquid separators are provided at a distance of 5 m or more from each other.

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