JP3754977B2 - Waste water treatment apparatus and operation method thereof - Google Patents

Description

  The present invention relates to a wastewater treatment apparatus and an operation method thereof, and more particularly, to a wastewater treatment apparatus by a membrane separation method that is relatively small and can be moved as necessary, and an operation method thereof.

  The solid-liquid separation method used in conventional wastewater treatment facilities is mainly a gravity precipitation method, and it has been difficult to reduce the size of the facility. In addition, although a simple structure such as a moat pond that is relatively easy to install and remove is known, relocation requires considerable time and cost. On the other hand, membrane separation methods, which have been rapidly put into practical use in the fields of sewage, manure, and water purification, can be separated into solid-liquid separation in a relatively compact facility compared to gravity precipitation, and can save labor. is there.

  However, it has been difficult to say that the wastewater treatment facilities using the membrane separation method so far still fully utilize the advantages of the membrane separation method.

  Accordingly, an object of the present invention is to provide a wastewater treatment apparatus that can fully utilize the advantages of the membrane separation method, can be miniaturized, and can accommodate relocation, and an operation method thereof.

In order to achieve the above object, the wastewater treatment apparatus of the present invention divides a treatment tank for purifying sewage into a first treatment tank and a second treatment tank by an overflow weir, and flows raw water into the first treatment tank. The first inflow path and the second inflow path for allowing the raw water to flow into the second treatment tank, the first circulation path and the second for agitating the treated water by circulating the treated water in the first treatment tank into the first treatment tank Circulating the treated water in the treatment tank into the second treatment tank and agitating the treated water, and discharging the treated water in the first treatment tank and the second treatment tank through the membrane separation device, respectively. A first drainage path and a second drainage path, a first introduction path for introducing treated water in one treatment tank into the other treatment tank, a second introduction path formed by the overflow weir, and a first treatment Aeration air is introduced into the first aeration path and the second treatment tank for introducing aeration air into the tank. It is characterized in that a second aeration path for.

Moreover, the operation method of the waste water treatment apparatus of the present invention is to divide a treatment tank for purifying the waste water into a first treatment tank and a second treatment tank by an overflow weir, and perform anaerobic operation in one treatment tank, and the other When performing aerobic operation in each of the treatment tanks, raw water is allowed to flow into the treatment tank performing anaerobic operation and part of the treated water derived from the treatment tank performing aerobic operation is routed through the first introduction path. Circulate and flow into the treatment tank performing anaerobic operation, stir the tank, and allow the treatment water from the treatment tank performing anaerobic operation to overflow into the overflow weir. At the same time, the remaining portion of the treated water derived from the treatment tank performing the aerobic operation is circulated into the treatment tank performing the aerobic operation to stir the tank, and the treated water in both treatment tanks is subjected to membrane separation. through the apparatus, the sludge in the respective processing tanks It is characterized by withdrawing from each sludge path.

  As described above, according to the present invention, advanced wastewater treatment can be performed with a simple device configuration, and construction and removal can also be performed quickly.

  Hereinafter, the present invention will be described in more detail with reference to the drawings. FIG. 1 is a system diagram showing an example of a wastewater treatment apparatus of the present invention, and FIG. 2 is an explanatory diagram of an operation method.

  First, as shown in FIG. 1, the waste water treatment apparatus shown in the present embodiment is an example in which a treatment tank 51 is partitioned by an overflow weir 52 to form a first treatment tank 60 and a second treatment tank 70. The first inflow path 61 and the second inflow path 71 through which the raw water flows into the treatment tanks 60 and 70, and the treated water in the treatment tanks 60 and 70 are discharged through the membrane separators 62 and 72, respectively. The drainage path 63 and the second drainage path 73, the first circulation path 64 and the second circulation path for agitating the treated water by deriving the treated water in each of the treatment tanks 60 and 70 and circulating them in each of the treatment tanks 60 and 70. A circulation path 74; a first introduction path 65 for introducing treated water in one treatment tank into the other treatment tank using the first circulation path 64 and the second circulation path 74; and the overflow weir. 52, the second introduction path 75 formed by 52, A first aeration path 66 and a second aeration path 76 for introducing aeration air into the treatment tanks 60 and 70, and a first sludge derivation path 67 and a second sludge derivation path 77 for deriving sludge in the treatment tanks 60 and 70, respectively. And are provided respectively.

  The 1st inflow path 61 and the 2nd inflow path 71 are branched downstream of the screen 2 provided in the raw | natural water inflow path 1, and the 1st drainage path 63 and the 2nd drainage path 73 are post-processes, such as a UV sterilizer They merge at the inlet of the device 3. Further, the first sludge outlet path 67 and the second sludge outlet path 77 merge at the inlet of the sludge storage tank 4, and the excess sludge in the sludge storage tank 4 is dehydrated by the sludge treatment equipment 5 and then containerized. The residue from the screen 2 is also processed by the residue processor 7 and transferred to the container 6b. In addition, a pump (P) and a valve are provided at necessary portions of each path, and a blower (B) is provided at both aeration paths 66 and 76.

  Further, the ejection portions in the first and second treatment tanks 60 and 70 of the first and second aeration paths 66 and 76 are provided in the first and second circulation paths 64 and 74 by an injector method, and aeration air is provided. Is formed so as to be ejected into the treatment tanks 60 and 70 in a state of being dispersed in the treatment water circulating through the circulation paths 64 and 74. Moreover, the installation position is set to a position where the membrane separators 62 and 72 can be cleaned with aerated air. The membrane separation devices 62 and 72 and the ejection unit are provided with a plurality of units in consideration of membrane cleaning described later. In addition, each circulation path 64, 74 is configured to suck and discharge the treated water in the tank by the pumps 64P, 74P to stir the treated water, but instead of this, a normal stirring device can be provided.

  Next, an operation method of the wastewater treatment apparatus of FIG. 1 at the planned water amount will be described with reference to FIG. FIG. 2 shows an anaerobic operation in one treatment tank, for example, the first treatment tank 60, an aerobic operation in the second treatment tank 70, which is the other treatment tank, and the treated water in the second treatment tank 70. The example which performs the waste_water | drain process by the circulation method which circulates a part of this to the 1st process tank 60 is shown.

  First, a predetermined amount of raw water is introduced into the first treatment tank 60 performing the anaerobic operation from the first inflow path 61 and a part of the treated water derived from the second treatment tank 70 through the valve 74V is used. The pump 64P is circulated through the first introduction path 65, the valve 65V, and the first circulation path 64. At the same time, the treated water in the first treatment tank 60 is discharged from the membrane separation device 62 via the pump 63P and the first drainage path 63.

  In addition, the treated water in the first treatment tank 60 flows into the second treatment tank 70 performing the aerobic operation by overflowing the overflow weir 52 (second introduction path 75). As described above, a part of the treated water in the inside circulates to the first treatment tank 60 through the first introduction path 65 and the first circulation path 64, and the remaining part passes through the second circulation path 74 by the pump 74P. It circulates to the 2nd processing tank 70 through, and the inside of a tank is stirred. At the same time, an aeration process is performed by the blower 76B of the second aeration path 76, and the treated water is discharged from the second drainage path 73 and the pump 73P via the membrane separator 72.

  In the wastewater treatment by such a circulation method, since the nitrogen removal rate is determined by the circulation rate of the treated water from the second treatment tank 70 to the first treatment tank 60, a removal rate of a certain degree or more cannot be desired. Stable operation can be performed with a simple operation by setting the rate appropriately.

  Then, the anaerobic operation in the first treatment tank 60 and the aerobic operation in the second treatment tank 70 are switched for an appropriate period, for example, every day, thereby performing membrane separation by aeration treatment during aerobic operation. The deposits (cake layer) on the devices 62 and 72 can be removed.

  Therefore, this circulation method can be selected according to the management level from the intermittent aeration method shown in FIG. 3 described later. If a stable operation state is desired with a certain nitrogen removal rate, the circulation method can When nitrogen removal is required, the intermittent aeration method may be employed.

  FIG. 3 is an example of the intermittent aeration method of the wastewater treatment apparatus of FIG. 1, and shows an operation method when the inflow amount of raw water is the planned water amount of the wastewater treatment apparatus. In this example, sewage is treated by anaerobic and aerobic methods.

  A predetermined amount of raw water is introduced into the first treatment tank 60 and the second treatment tank 70 from the first inflow path 61 and the second inflow path 71, respectively. The treated water in 60 and 70 is circulated in each treatment layer and stirred, and the treated water in each treatment tank is discharged from the first drainage path 63 and the second drainage path 73 through the membrane separators 62 and 27. To do. And the aeration operation by the 1st aeration path | route 66 and the 2nd aeration path | route 76 is made to perform intermittently about both the processing tanks 60 and 70, respectively.

  Thus, in each processing tank 60 and 70, the aerobic process and the anaerobic process of a waste water are performed alternately. This operation method (intermittent aeration method) can improve the nitrogen removal rate by appropriately setting the time allocation between the aerobic operation and the anaerobic operation, and can perform advanced water purification treatment. Moreover, you may make it both the processing tanks 60 and 70 perform anaerobic operation or aerobic driving simultaneously.

  In FIG. 3, the first treatment tank 60 is in a non-aeration operation (anaerobic operation) and the second treatment tank 70 is in an aeration operation (aerobic operation). The valves 61V and 71V of the valves 61 and 71 and the valves 64V and 74V of the first and second circulation paths 64 and 74 are opened, respectively, the pumps 63P and 73P of the first and second drainage paths 63 and 73, and the first and second circulations. The pumps 64P and 74P of the paths 64 and 74 are operating, and the blower 76B of the second aeration path 76 is operating in the first and second aeration paths 66 and 76.

  Further, by alternately performing an aerobic operation and an anaerobic operation, the deposit (cake layer) of the membrane separation device 12 can be removed by aeration processing during an aerobic operation, and a stable operation is performed over a long period of time. be able to.

  The suction and discharge of the treated water from the membrane separation devices 62 and 72 is desirably performed intermittently and is preferably stopped at a time ratio of about 1/5 to 1/10 during the operation time. Furthermore, it is usually preferable to set the permeation flow rate of the membrane in the range of 0.24 to 0.4 m per day.

  FIG. 4 shows an example of the operation state when the amount of water is smaller than the planned water amount in the above operation state, and the waste water treatment by the intermittent aeration method is performed in one of the first treatment tank 60 and the second treatment tank 70. And the other processing tank is set in a standby state.

  For example, when the first treatment tank 60 is set in a standby state, in the second treatment tank 70, raw water is introduced from the second inflow path 71 and the second treatment path 74 is used to circulate the treated water in the tank. The aeration by the two aeration paths 76 is intermittently performed, and the waste water treatment by the above-described intermittent aeration method in which the treated water in the second treatment tank 70 is discharged from the second drainage path 73 through the membrane separator 72 is performed.

  In the first treatment tank 60, the treated water in the first treatment tank 60 is discharged to some extent from the first drainage path 63 via the membrane separator 62 to concentrate the sludge, and then the pump of the first sludge outlet path 67. 67P is operated to remove excess sludge from the tank. Thereby, since excess sludge can be extracted in a concentrated state, the sludge can be easily treated, and maintenance work such as cleaning of the membrane separation device 62 is performed.

  In order to guarantee the performance of the membrane, the membrane separation devices 62 and 72 need to wash the membrane with a chemical solution at an appropriate time. For example, the membrane separation devices 62 and 72 are operated by the operation method at the time of low water amount shown in FIG. Can be done easily when.

  That is, in the operation at the time of low water amount shown in FIG. 3, the membrane separation device in which one unit among the membrane separation devices 62 provided in the plurality of units of the first treatment tank 60 with the low water amount is pulled up and pulled up. The chemical solution in the chemical solution adjusting tank is poured into 62 and left for a predetermined time, for example, about 1 hour, to clean the film. Thereafter, the membrane separation device 62 may be returned to the treated water to start discharging the treated water.

  As shown in this embodiment, this wastewater treatment device performs solid-liquid separation with a membrane separation device, so there is no need to provide a sedimentation basin. It can be done and relocation can be done easily. Moreover, construction and removal can be quickly performed by unitizing the membrane separation device and the aeration device.

  Further, the amount of sludge generated can be reduced by the high concentration MLSS, and nitrogen can be removed by the intermittent aeration method. In addition, the membrane can be cleaned by a simple operation on site and can be automated according to the amount of raw water inflow. In addition, when removing excess sludge, it is possible to reduce the volume of excess sludge by removing the treated water through a membrane to some extent, and by using an ultraviolet sterilizer as a post-treatment device, it is safe and highly advanced. Can be obtained.

It is a systematic diagram which shows an example of the 2 tank type waste water treatment equipment of this invention. It is explanatory drawing which shows the driving | running state of the circulation method of this invention. It is explanatory drawing which shows the aerobic and anaerobic driving | running state at the time of plan water quantity. It is explanatory drawing which shows the driving | running state at the time of low water quantity.

Explanation of symbols

  60, 70 ... 1st, 2nd processing tank, 61, 71 ... 1st, 2nd inflow path, 62, 72 ... Membrane separator, 63, 73 ... 1st, 2nd drainage path, 64, 74 ... 1st , Second circulation path, 65, 75 ... first, second introduction path, 66, 76 ... first, second aeration path

Claims (2)

A treatment tank for purifying the sewage is divided into a first treatment tank and a second treatment tank by an overflow weir, and a first inflow path for inflowing raw water into the first treatment tank and a first inflow of raw water into the second treatment tank. Circulate the treated water in the second treatment tank and the first inflow path and the first circulation path for circulating the treated water in the first treatment tank in the first treatment tank and stirring the treated water. The first circulation path for agitating the treated water, the first drainage path and the second drainage path for draining the treated water in the first treatment tank and the second treatment tank through the membrane separator, respectively, and one treatment A first introduction path for introducing treated water in the tank into the other treatment tank and a second introduction path formed by the overflow weir, a first aeration path for introducing aeration air into the first treatment tank, and a second Drainage characterized by comprising a second aeration path for introducing aeration air into the treatment tank Management apparatus. The treatment tank for purifying sewage is divided into a first treatment tank and a second treatment tank by an overflow weir, and anaerobic operation is performed in one treatment tank and aerobic operation in the other treatment tank. The raw water is allowed to flow into the operating treatment tank and a part of the treated water derived from the aerobic operation treatment tank is circulated into the treatment tank performing the anaerobic operation via the first introduction path. The water inside the tank is agitated, and the treatment water in the anaerobic operation is discharged from the treatment tank in which the treatment water in the anaerobic operation is allowed to overflow and flow into the overflow weir. The remainder of the treated water is circulated and flowed into the treatment tank performing aerobic operation, the inside of the tank is agitated, and the treated water in both treatment tanks is discharged through the membrane separator , respectively, and the sludge in each treatment tank especially that pull out from the sludge path How the operation of the wastewater treatment device according to.

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