JP2000271581A - Membrane treatment type septic tank - Google Patents

Abstract

PROBLEM TO BE SOLVED: To keep the concn. of activated sludge in a secondary treatment tank proper by rationally grasping the generation of excessive sludge regardless of a treatment mode. SOLUTION: In a membrane treatment type septic tank equipped with a primary treatment tank 1 in which water to be treated is charged, a secondary treatment tank 2 performing the membrane treatment of the primarily treated water transferred from the primary treatment tank 1 by a membrane separator 6, a discharge pump 3 discharging the secondarily treated water in the secondary treatment tank 2 to the outside and a sludge withdrawing pump 4 returning excessive sludge in the secondary treatment tank 2 to the primary treatment tank 1, a control part 5 operating the sludge withdrawing pump 4 when integrated water quantity obtained by integrating the quantity of membrane-treated water in the membrane separator 6 reaches a specified quantity is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a membrane treatment / purification tank, and more particularly, to appropriately grasp the generation of excess sludge and to maintain an appropriate concentration of activated sludge in a secondary treatment tank regardless of a treatment mode. It concerns technology.

[0002]

2. Description of the Related Art Conventionally, a primary treatment tank into which water to be treated is charged, a secondary treatment tank in which a primary treatment water is transferred from the primary treatment tank and subjected to membrane treatment by a membrane separator immersed therein, and a secondary treatment tank In a membrane treatment type purification tank equipped with a discharge pump that discharges secondary treatment water in the tank to the outside and a sludge extraction pump that returns excess sludge in the secondary treatment tank to the primary treatment tank,
In order to keep the activated sludge concentration in the secondary treatment tank at an appropriate level, it is necessary to extract an appropriate amount of excess sludge.

Generally, the generation of excess sludge is proportional to the inflow load and the amount of filtered water, and the amount of generated excess sludge is estimated by detecting the amount of filtered water. By the way, when detecting the amount of filtered water, without using a special sensor, the number of times of membrane filtration treatment, that is, the membrane filtration starts from the upper limit set water level, and the lower limit set water level to stop the discharge pump as one cycle. A method of counting and counting the number of counts to a predetermined number and performing sludge extraction is conceivable.

However, a membrane separation type purification tank having a primary treatment tank into which water to be treated is charged, and a secondary treatment tank in which the primary treatment water treated in the primary treatment tank is transferred and intermittently aerated is performed. A normal mode in which aeration and aeration stop are repeated at predetermined time intervals based on upper and lower water level information in the primary and secondary treatment tanks, and water to be treated (sewage) is stored in the impurity separation and storage tank as the primary treatment tank. Energy-saving mode in which only a minimum aeration operation is performed in order to maintain the activity of activated sludge in the membrane separation device during the time when there is no inflow of
And, when the water to be treated flows into the primary treatment tank more than the design value, the primary treatment water is continuously supplied from the primary treatment tank to the secondary treatment tank, and the high-speed mode in which the treatment in the membrane separation device is continuously performed. It is an automatic driving system that automatically shifts to.

As described above, the nitrogen removal type membrane separation / combination treatment septic tank is a system that automatically shifts to any of the normal mode, the energy saving mode, and the high-speed mode based on the water level information of each tank. When the mode is shifted to the high-speed mode, there is a problem that the above-described method of extracting sludge based on the detection of the water level in the normal mode cannot be performed.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of such a problem, and properly grasps the generation of surplus sludge without depending on the treatment mode and removes the excess sludge in the secondary treatment tank. It is an object of the present invention to provide a membrane treatment type septic tank that can be appropriately pulled out to maintain the activated sludge concentration at an appropriate level.

[0007]

According to the first aspect of the present invention, the membrane treatment is performed by a primary treatment tank 1 into which water to be treated is charged, and a membrane separation device 6 in which the primary treatment water from the primary treatment tank 1 is transferred and immersed. Treatment tank 2 which performs the following, a discharge pump 3 for discharging secondary treatment water in the secondary treatment tank 2 to the outside, and a sludge extraction pump for returning excess sludge in the secondary treatment tank 2 to the primary treatment tank 1 And a control unit 5 for operating the sludge extraction pump 4 when the integrated water amount obtained by integrating the membrane treatment water amount in the membrane treatment device 6 reaches a certain amount. It is a feature. According to such a configuration, the amount of membrane treatment water in the membrane treatment device 6 can be integrated in any treatment mode, and the excess sludge withdrawal that increases as the amount of membrane treatment water increases can be appropriately removed. It is something that can be done.

According to a second aspect of the present invention, the integrated amount of water subjected to the membrane treatment is converted by the integrated time obtained by integrating the operation time of the discharge pump 3. According to such a configuration, the configuration can be simplified as compared with the integration of the amount of membrane treatment water.

According to a third aspect of the present invention, there is provided a secondary treatment tank for performing a membrane treatment by a primary treatment tank 1 into which water to be treated is charged and a membrane separation device 6 in which the primary treatment water from the primary treatment tank 1 is transferred and immersed. 2, a discharge pump 3 for discharging secondary treatment water in the secondary treatment tank 2 to the outside, and a sludge extraction pump 4 for returning excess sludge in the secondary treatment tank 2 to the primary treatment tank 1. A treatment-type septic tank, in which the water level in the secondary treatment tank 2 reaches the upper limit set water level H2 at least once per unit time is counted as one time, and when the count reaches a predetermined number, the sludge removal pump is used. Control unit 5 for driving 4
It is characterized by having. According to such a configuration, even if the water level exceeds the upper limit set water level H2 many times per unit time due to, for example, an excessive inflow, the water level is counted as one time, and even in the high-speed mode, excessive sludge extraction is avoided. And can maintain an appropriate activated sludge concentration.

According to a fourth aspect of the present invention, there is provided a primary treatment tank for charging the water to be treated, and a secondary treatment tank for carrying out the membrane treatment by the membrane separation device in which the primary treatment water from the primary treatment tank is transferred and immersed. 2, a discharge pump 3 for discharging secondary treatment water in the secondary treatment tank 2 to the outside, and a sludge extraction pump 4 for returning excess sludge in the secondary treatment tank 2 to the primary treatment tank 1. If the accumulated operation time of the discharge pump 3 reaches the predetermined time once per unit time, the sludge removal pump 4 is operated once, and the discharge pump 3 is operated within the unit time thereafter. If the integration of the operation time was stopped, and if the integrated operation time of the discharge pump 3 did not reach the predetermined time per unit time, the operation time was integrated even in the next unit time and reached the predetermined time. Sludge withdrawal pong at time And it is characterized in that it comprises a control unit 5 for operating a 4.

According to such a configuration, for example, when there are a large number of visitors, the high-speed mode is set and the discharge pump 3
When the accumulated time of the operation reaches a predetermined time per unit time (for example, 24 hours), the sludge extraction pump 4 is operated to extract sludge. However, in the remaining time of the unit time, the discharge pump 3 It does not accumulate the operating time even when the system is operating, avoids sludge withdrawal many times per unit time, avoids excessive sludge withdrawal, and has an appropriate activity Sludge concentration can be maintained.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory diagram of a septic tank, and FIG. 2 is a flowchart showing a normal mode.

As shown in FIG. 1, the septic tank is, for example, an intermittent aeration type nitrogen removal type membrane separation / combination septic tank in which aeration and an aeration stop are performed in a single tank. Once stored in the impurity separation and storage tank (also serving as a flow rate adjustment tank) 1a as the primary treatment tank 1 to make the organic matter concentration of the sewage uniform, the secondary treatment tank is fixedly transferred by a transfer pump 10 in the sewage transfer tank. It is transferred to a membrane separation intermittent gas tank 2 a provided with a membrane separation device 6 as 2. In the intermittent membrane separation gas tank 2a, organic wastewater is biologically treated with activated sludge in the membrane separation device 6, and solid-liquid separation is performed in the immersion type membrane separation device 6. Further, the anaerobic state and the aerobic state are created by repeatedly stopping and operating the blower 7 and nitrogen is removed by controlling the dissolved oxygen amount (DO) of the sewage in the tank. Further, a sludge pulling pump (a lift pump) 4 is provided in the tank, and a certain amount of excess sludge is drawn into the impurity separating / storing tank 1a according to the setting of the control unit 5, and the MLSS
(Activated sludge concentration) is operated within a certain range. Reference numeral 15 denotes an air diffuser, and 17 denotes a blower for extracting sludge.

The outlet pipe 8 for the membrane permeated liquid is connected to a treatment water tank 9 opened at atmospheric pressure in the purification tank, and the membrane separation device 6 performs siphon filtration by the siphon action of the head difference suction force h. It is configured. The membrane permeate is taken out by the discharge pump 3 and discharged through the disinfection tank 12 at a constant flow rate according to the setting of the flow control valve 11.

A water level sensor 13 is provided in the impurity separation storage tank 1a.
Is provided, and L1 (lowest water level) and H1 (highest water level) can be detected. Usually, the tank capacity is designed so that the operation is performed with the flow rate adjustment range between L1 and H1. On the other hand, the membrane separation intermittent gas tank 2a is provided with a water level sensor 14 capable of detecting L2 (lowest water level) and H2 (highest water level), and the amount of filtration in one cycle corresponds to the capacity defined by L2 and H2. . Based on the water level information, the control unit 5 performs the following automatic operation.

That is, the transfer pump 10 operates at the level of the contaminant separation and storage tank L1 (minimum water level) during the abrupt stop time,
The operation is performed until the water level of the intermittent membrane separation air tank 2a becomes H2 (the highest water level). At the end of the aeration time, if the water level of the impurity separation and storage tank 1a is lower than L1, the mode is switched to a mode in which only the minimum aeration operation for maintaining the activity of the sludge (an energy saving mode) is performed, thereby reducing the electricity bill. On the other hand, when the water level becomes higher than the water level H1 (highest water level) of the impurity separation storage tank 1a,
The mode is switched to the high-speed mode, and the sewage is charged into the intermittently-absorbed membrane tank 2a, and the membrane treatment is continuously performed. The discharge pump 3 is operated only during the aeration time, and performs the membrane treatment by operating the water level of the intermittent membrane separation aeration tank 2a from H2 (highest water level) to L2 (lowest water level).

Further, in the normal mode, as shown in FIG.
For example, in the aeration operation in which the aeration blower 7 is operated for 30 minutes based on the detection result of the maximum water level H2 in the intermittent aeration tank 2a, the transfer pump 10 is stopped and the discharge pump 3 is operated. The treated water from the membrane separation device 6 is transferred to the disinfection tank 12, and when the water level in the intermittent membrane separation aeration tank 2a reaches the lowest position L2, the discharge pump 3 is stopped based on the detection result, Membrane separation intermittent aeration tank 2a
Is maintained at the minimum water level L2, the aeration blower 7 is operated for a while and stopped, and the operation shifts to the aeration stop operation.
The transfer pump 10 is operated at the beginning of the aeration stop operation,
The water is transferred from the impurity separation storage tank 1a to the membrane separation intermittent aeration tank 2a up to the highest water level. Such an aeration stop operation is performed, for example, for 30 minutes, and thereafter, the above-described aeration operation is performed, and this is repeated.

In the membrane treatment type septic tank constructed as described above, the invention of claim 1 operates the sludge extraction pump 4 when the integrated water amount obtained by integrating the membrane treatment water amount in the membrane treatment device 6 reaches a certain amount. It was made. Specifically, for example, a water meter may be installed in the discharge water channel 16, the amount of water may be integrated, and the detection result may be input to the control unit 5. Thus, the amount of membrane treatment water in the membrane treatment device 6 can be integrated not only in the normal mode but also in the high-speed mode, and the excess sludge that increases as the amount of membrane treatment water increases can be appropriately extracted. Things.

FIG. 3 is a flow chart showing a second embodiment of the present invention. In the present embodiment, the discharge pump 3 is used to obtain the integrated water amount subjected to membrane treatment by the membrane separation device 6.
Is converted by the accumulated time obtained by accumulating the operation time. The details will be described below.

When the normal mode operation is performed for one day (24 hours), the discharge pump 3 is operated for about 12 hours. In the present embodiment, when the timer for accumulating the operation time of the discharge pump 3 reaches 12 hours, the sludge extraction pump 4 is operated on the assumption that the amount of filtered water has reached the processing amount for one day. [Refer to FIG. 3 (a)]. In this case, the discharge pump 3
When the accumulated operation time reaches a predetermined time (12 hours) [see (b) in FIG. 3B], this is used as a trigger to reset the timer and start the operation of the sludge extraction pump 4 at the start of the next aeration operation. [See FIG. 3 (b)].

Even when the mode shifts to the high-speed mode, the counting of the timer for integrating the operation time of the discharge pump 3 is continued. If the time is up during the high-speed mode [see FIG. At the start of the first aeration time after the mode shift, the operation of the sludge extraction pump 4 is started. That is, in the high-speed mode, since the water to be treated is being transferred from the primary treatment tank 1, the return of the drawn sludge to the primary treatment tank 1 is not performed. By such a method, even at the time of transition to the high-speed mode, sludge extraction according to the amount of treated water can be performed.

Similarly, when the energy saving mode is entered for several hours during one day and reaches a predetermined time during the normal mode [FIG.
(See (a) e)], since the discharge pump 3 does not operate during the energy saving mode, the operation time integration timer is stopped, and sludge can be extracted by integrating the operation time of the discharge pump 3 in the normal mode.

According to the third aspect of the present invention, in the high-speed mode, it is determined that the water level in the secondary treatment tank 2 has reached the upper limit set water level H2 at least once per unit time.
The number of times is counted, and the sludge extraction pump 4 is operated when the counted number reaches a predetermined number.
Therefore, even if the water level exceeds the upper limit set water level H2 many times per unit time due to, for example, excessive inflow, the water level is counted as one time. Therefore, even in the high-speed mode, it is possible to avoid excessive sludge withdrawal. Activated sludge concentration can be maintained.

FIG. 4 is a flow chart showing the fourth embodiment. When the amount of inflowing water to be treated is large constantly, the high-speed mode is frequently entered. For this reason, in the embodiment described with reference to FIG. 3, sludge extraction is performed excessively. There is a possibility that the activated sludge concentration in the tank 2 becomes low and the treatment capacity by the activated sludge is deteriorated. Therefore, in the invention of claim 4,
If the integrated operation time of the discharge pump 3 reaches the predetermined time once per unit time (24 hours), the sludge extraction pump 4 is operated once, and the unit time (2
(4 hours), the integration of the operating time of the discharge pump 3 is stopped, and if the integrated operation time of the discharge pump 3 does not reach the predetermined time within a unit time (24 hours), the next unit time Also in (24 hours), the sludge extraction pump 4 is operated when the operation time is accumulated and reaches a predetermined time. The details will be described below.

After the operation of the 24-hour (unit time) timer is started, the operation of the timer for integrating the operation time of the discharge pump 3 is started.
When the time (predetermined time) has been reached, the operation time integration timer is reset and a trigger for operating the sludge extraction pump 3 is set. The operation timing of the sludge extraction pump 4 is the same as in the embodiment of FIG. 3, at the start of the first aeration time after the trigger is activated (normal mode). By the way, the 24-hour timer keeps measuring time,
The running time integration timer is reset when the 24-hour timer expires, and then both timers are restarted.

On the other hand, if the running time integration timer has not reached the predetermined time within 24 hours and has not timed out, the 24-hour timer is reset and stopped. Thereafter, the time when the operation time integration timer has expired is used as a sludge extraction trigger, and at the same time,
It starts the operation of the time timer.

According to such a configuration, for example, when there are a large number of customers, the high-speed mode is set and the discharge pump 3
When the integrated time of the operation reaches a predetermined time per unit time (24 hours), the sludge withdrawal pump 4 is operated to perform sludge withdrawal. In the remaining time of the unit time, the discharge pump 3 Even during operation, the operation time is not integrated, and it is possible to avoid pulling out sludge many times in a unit time, and it is possible to avoid excessive sludge withdrawal. The concentration can be maintained.

[0028]

According to the first aspect of the present invention, there is provided a primary treatment tank into which water to be treated is charged, and a secondary treatment tank in which the primary treatment water is transferred from the primary treatment tank and subjected to membrane treatment by a membrane separation device immersed therein. A membrane treatment type purification tank comprising a discharge pump for discharging secondary treatment water in the secondary treatment tank to the outside, and a sludge extraction pump for returning excess sludge in the secondary treatment tank to the primary treatment tank, Since the control unit that operates the sludge extraction pump is provided when the integrated water amount obtained by integrating the membrane treatment water amount in the membrane treatment device reaches a certain amount, it is necessary to integrate the membrane treatment water amount in the membrane treatment device regardless of the treatment mode. Therefore, there is an advantage that the excess sludge, which increases with an increase in the amount of membrane treatment water, can be appropriately extracted.

According to the second aspect, the integrated water amount subjected to the membrane treatment is converted by the integrated time obtained by integrating the operation time of the discharge pump. There is an advantage that it can be simplified.

According to a third aspect of the present invention, there is provided a primary treatment tank into which water to be treated is charged, a secondary treatment tank in which the primary treatment water from the primary treatment tank is transferred and subjected to membrane treatment by a membrane separator immersed therein. A membrane treatment type purification tank comprising a discharge pump for discharging secondary treatment water in the secondary treatment tank to the outside, and a sludge extraction pump for returning excess sludge in the secondary treatment tank to the primary treatment tank. The control unit operates the sludge extraction pump when the water level in the treatment tank reaches the upper limit set water level at least once per unit time and is counted as one, and when the count reaches a predetermined number. For example, even if the upper limit water level is exceeded many times per unit time due to an excessive inflow, the water level is counted as one time. Therefore, even in the high-speed mode, it is possible to avoid excessive sludge withdrawal. There is an advantage that it is possible to maintain the sexual sludge concentration.

According to a fourth aspect of the present invention, there is provided a secondary treatment tank in which water to be treated is charged, a secondary treatment tank in which the primary treatment water from the primary treatment tank is transferred and subjected to membrane treatment by a membrane separator immersed therein. A membrane treatment type purification tank comprising a discharge pump for discharging secondary treatment water in the secondary treatment tank to the outside, and a sludge extraction pump for returning excess sludge in the secondary treatment tank to the primary treatment tank. If the integrated operation time of the predetermined time reaches the predetermined time once per unit time, the sludge extraction pump is operated once, and the accumulation of the operation time of the discharge pump within the unit time after that is stopped, and If the integrated operation time of the discharge pump does not reach the predetermined time per unit time, the control unit operates the sludge extraction pump at the time when the operation time is integrated and reaches the predetermined time even in the next unit time. Therefore, for example, when there is a large number of visitors, the high-speed mode is set, and when the integrated time of the operation of the discharge pump reaches a predetermined time per unit time (for example, 24 hours), the sludge extraction pump is operated to activate the sludge removal pump. In the remaining time of the unit time, even if the discharge pump is operated, the operation time is not integrated, and the sludge is not repeatedly extracted in the unit time. This has the advantage that excessive sludge extraction can be avoided and an appropriate activated sludge concentration can be maintained.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a septic tank according to the present invention.

FIG. 2 is a flowchart showing a normal mode according to the first embodiment;

FIGS. 3A and 3B are flowcharts of the first embodiment.

FIG. 4 is a flowchart of the second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Primary treatment tank 2 Secondary treatment tank 3 Discharge pump 4 Sludge extraction pump 5 Control part 6 Membrane separation device

Continuing on the front page (72) Inventor Shin Shin, 1048, Kadoma, Kadoma, Osaka Prefecture Inside Matsushita Electric Works Co., Ltd. (72) Inventor Hiroshi Kano 1048, Oaza, Kadoma, Kadoma, Osaka Prefecture Matsushita Electric Works Co., Ltd. (72) Invention Person Shigeyuki Yamaguchi 1048 Kazuma Kadoma, Kadoma City, Osaka Prefecture Inside the Matsushita Electric Works, Ltd. PC65 4D027 AA01 AA14 4D028 AA08 BC17 BD08 BD11 BD17 CA09 CA15 CB02 CB08 CD00 CD05

Claims (4)

[Claims] 1. A primary treatment tank into which water to be treated is charged, a secondary treatment tank in which a primary treatment water from the primary treatment tank is transferred and subjected to membrane treatment by a membrane separator immersed therein, and a secondary treatment tank And a sludge removal pump for returning excess sludge in the secondary treatment tank to the primary treatment tank. A membrane treatment type purification tank comprising a control unit for operating a sludge extraction pump when the integrated water amount obtained by integrating the water amount reaches a certain amount. 2. The membrane-treated septic tank according to claim 1, wherein the integrated amount of water subjected to the membrane treatment is converted by the integrated time obtained by integrating the operation time of the discharge pump. 3. A primary treatment tank into which water to be treated is charged, a secondary treatment tank in which a primary treatment water from the primary treatment tank is transferred and subjected to membrane treatment by a membrane separation device immersed therein, and a secondary treatment tank. And a sludge extraction pump for returning excess sludge in the secondary treatment tank to the primary treatment tank, wherein the water level in the secondary treatment tank is provided. Is characterized by comprising a control unit that counts at least once per unit time to reach the upper limit set water level as one time, and operates the sludge extraction pump when the counted number reaches a predetermined number. Membrane treatment type septic tank. 4. A primary treatment tank into which water to be treated is charged, a secondary treatment tank for performing a membrane treatment by a membrane separation device in which primary treatment water is advected and immersed from the primary treatment tank, and a secondary treatment tank. A membrane treatment type purification tank provided with a discharge pump for discharging the secondary treatment water to the outside and a sludge extraction pump for returning excess sludge in the secondary treatment tank to the primary treatment tank, and the cumulative operation time of the discharge pump If the predetermined time is reached once per unit time, the sludge pulling pump is operated once, and the accumulation of the operating time of the discharge pump within the unit time thereafter is stopped. If the operation time does not reach the predetermined time per unit time, a control unit is provided that operates the sludge extraction pump when the operation time is integrated and reaches the predetermined time even in the next unit time. To be Membrane treatment type septic tank.