JP2000246245A - Waste water treatment apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a waste water treatment apparatus using a membrane filtering device with a small area of installation and good filtering efficiency. SOLUTION: In a waste water treatment apparatus 1 wherein anaerobic tanks 2 and 3, a membrane filtering tank 25 and a disinfection tank and a treated water tank 35 are provided, an overflow pipe 29 connecting the membrane filtering tank 25 with the anaerobic tank 3 is provided above the membrane filtering device and water to be treated is filtered by water head pressure caused by fall head between the overflow pipe 29 and an outlet 34 of the membrane filtering device and it is ordinarily filtered by water head pressure between the height of an advection hole of the disinfection tank and the water level of the overflow pipe 29.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a sewage treatment apparatus using a membrane filtration device.

[0002]

2. Description of the Related Art Conventionally, the filtration capacity of a conventional membrane filtration device is as follows.
Depending on the difference between the water level of the membrane filtration tank and the head pressure of the filtered water discharge port of the membrane filtration device, the water level of the membrane treatment tank is the highest when adjusting the flow rate of the pretreatment tank. There is a gravity filtration method based on the difference in water level at the outlet. Separate from this, JP-A-9-141277 and JP-A-9-7596
6, JP-A-9-136092, JP-A-9-1740
There is also a method in which transfer between all processing tanks is performed by a pump, as described in Japanese Patent Publication No. 74 or the like.

[0003]

In the case of the conventional gravity filtration method, the membrane filtration speed becomes slow due to a small head difference. Therefore, when a large amount of treatment is required, the filtration area must be increased, which is economically disadvantageous. If the tank is deepened to increase the head pressure difference, the ground will be dug deep, and the workability will be poor. Further, when the projection area is increased in order to increase the membrane area, there is a problem that the installation area of the sewage treatment tank increases. In addition, when a submersible pump is installed in the inflow tank and transferred to the next step as seen in the prior art, there is a possibility that inflow sludge and sediment including impurities are also transferred.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a sewage treatment apparatus using a membrane filtration device having a small installation area and high filtration efficiency. It is.

[0005]

According to the first aspect of the present invention, there is provided a sewage treatment apparatus according to the present invention, wherein an anaerobic tank, a membrane filtration tank in which a plurality of filtration membranes are provided, and a membrane filtration tank are provided. A treatment water tank provided with a disinfecting tank is a sewage treatment apparatus provided by separating the tank body, and the anaerobic tank is provided with a quantitative transfer device at a position higher than the water level of the anaerobic tank. Water is pumped to the quantitative transfer device by an air lift pump, and water is sent from the quantitative transfer device to the membrane filtration tank by a water supply pipe, and an overflow pipe connecting the membrane filtration tank and the anaerobic tank is above the water filtration pipe at a lower level of the water supply pipe. While being provided, the discharge port of the membrane filtration device is provided below the membrane filtration device, and the water to be treated is filtered at the head pressure due to the head drop between the overflow pipe and the discharge port of the membrane filtration device, and is stored in the treatment water tank. Is higher than the outlet of the membrane filtration device. Is intended to be filtered by the advection port height and the water head difference of the overflow pipe water level of disinfecting bath provided sufficiently lower position than the bar flow tube.

In the sewage treatment apparatus according to the present invention, a pump is provided in the treatment water tank, and the water to be treated in the treatment water tank is pumped to the disinfection tank by the pump, and the upper and lower water levels in the treatment water tank. Is controlled by a float switch, and is filtered by the head difference between the water level in the treated water tank and the overflow pipe.

According to a third aspect of the present invention, in the sewage treatment apparatus according to the present invention, the fixed amount transfer device includes a plurality of compartments, and the first compartment has a structure in which an inflow water discharge tip is submerged. The second compartment has a gate capable of adjusting the opening area for returning the excessively-treated water to be treated to the anaerobic tank, and a V-shaped measuring device is provided at the outlet before being sent to the membrane filtration tank. Is provided.

[0010] In the sewage treatment apparatus according to the present invention, an air diffuser and a backwash pipe are provided below a plurality of filtration membranes arranged in parallel in the membrane filtration tank. It can clean the film surface.

[0009]

In the sewage treatment apparatus according to the first aspect of the present invention, the water to be treated is filtered at a head pressure caused by a head drop between an overflow pipe and a discharge port of the membrane filtration device and stored in a treatment water tank. Since the water is filtered by the height of the aeration port of the disinfection tank provided at a position higher than the discharge port of the filtration device and sufficiently lower than the overflow pipe and the head difference of the overflow pipe water level,
By raising the upper manhole part of the membrane filtration tank and raising the water level of the membrane filtration tank, it is possible to increase the head difference between the advection port height of the disinfection tank and the overflow pipe water level, without having to dig deep into the tank The filtration speed can be improved by raising the upper manhole portion of the tank.

[0010] In the sewage treatment apparatus according to the present invention, the water to be treated transferred from the discharge port to the treatment water tank is pumped to the disinfection tank by a pump provided in the treatment water tank. The water level is controlled by a float switch, and the water is filtered by the head difference between the water level and the overflow pipe water level of the membrane filtration tank.If the water level reaches a certain level, the pump operates to pump up the treated water, and if the water level drops to a certain level, The operation can be stopped to automatically control the water level in the treated water tank.
Therefore, the water level at the outlet of the membrane filtration device of the treated water subjected to the filtration treatment is kept at a certain level by pumping the water to the disinfection tank, thereby maximizing the head pressure of the filtration membrane and improving the filtration speed. .

According to a third aspect of the present invention, in the sewage treatment apparatus according to the present invention, the quantitative transfer device includes a plurality of compartments, and the first compartment has a structure in which a discharge port is submerged. The compartment has a gate whose opening area can be adjusted to return excess water to be treated to the anaerobic tank, and a V-shaped measuring device is provided at the outlet before water is sent to the membrane filtration tank. Therefore, the water supply amount can be simply measured by a V-shaped measuring device, and the treated water can be quantitatively transferred to the membrane filtration tank.

In the sewage treatment apparatus according to the fourth aspect of the present invention, a diffuser tube and a backwash tube are provided below the plurality of filtration membranes juxtaposed in the membrane filtration tank, and the air filtration bubbles are optionally provided. Since the membrane surface can be washed, the filtration membrane surface can always be washed,
A solid substance adhering to the surface of the filtration membrane can be removed to prevent a decrease in filtration efficiency.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a vertical sectional view of a sewage treatment tank incorporating the membrane filtration device of the present invention, FIG. 2 is a horizontal sectional view of FIG. 1, and FIG. 3 is an explanatory diagram showing a two-stage air lift pump and a quantitative transfer device. 4 is a cross-sectional view showing an enlarged main part of the sewage treatment apparatus, and FIG. 5 is a perspective view of a disinfection tank.

As shown in FIGS. 1 and 2, a sewage treatment apparatus 1 according to the present invention comprises an anaerobic tanks 2 and 3 and a membrane filtration tank in which a membrane filtration device 25a for filtering water to be treated is filtered by a filtration membrane 26. 25 and a treated water tank 35 provided with a disinfection tank 38 at the top thereof
a is a sewage treatment apparatus 1 provided by fractionating a. The anaerobic tanks 2 and 3 divided into two chambers each have a filter bed 7 at the bottom,
8 are provided. In the present embodiment, the anaerobic tanks 2 and 3 are used as pretreatment tanks, the activated sludge method is adopted as the membrane processing tank, and the anaerobic tanks 3 and 2 are moved from the anaerobic tank 3 to the two-stage air lift pumps 10 and 15.
Using a quantitative transfer device 17 provided at the top of the
It is structured to be transferred to.

The water to be treated, which has flowed into the anaerobic tank 2, sediments and separates impurities therein, and is naturally transferred to the anaerobic tank 3, where the foreign substances and foreign substances clogging the membrane filtration device 25a are completely removed. It has been made to remove. In one chamber adjacent to the membrane filtration tank 25, a fixed amount transfer device 17 is provided at a position higher than the water level of the anaerobic tank 3.

A filter medium receiver 9 is provided at a position about 450 mm from the bottom of the anaerobic tank 2, and the filter medium 7 is filled thereon.
The treated water filtered by the filter medium 7 rises through an outflow pipe / cleaning hole 6 which forms a lower end below the filter medium receiver 9, and is transferred from the transfer port 5 to the anaerobic tank 3. It is further filtered by the filter medium 8 of the anaerobic tank 3, passes upward through the outflow pipe / cleaning hole 6 of the anaerobic tank 3, and is sucked up by the first-stage air lift pump 10. Although the filter media 7 and 8 use a skeleton spherical filter media made of a synthetic resin such as polyethylene, the filter media may be a mesh-like cylindrical or mesh-like plate-like filter material. .
The upper ends of the filter media 7 and 8 are air-lifted so that scum formed on the water surfaces of the anaerobic tanks 2 and 3 remains on the filter media 7 and 8 as the water level decreases and does not block the flow of water through the surfaces of the filter media 7 and 8. The pump 10 is lowered to 50-100 mm below the suction port 10a.

The air lift pumps 10 and 15 pump water to a quantitative transfer device 17 provided at a position sufficiently higher than the anaerobic tank 3 water level, for example, a height of 50 to 100 cm, from the quantitative transfer device 17 to a membrane filtration tank in the next step. 25. The height of the suction port 10 a of the first-stage air lift pump 10 is set to the low water level 43 of the anaerobic tank 3. That is, the low water level 43 of the anaerobic tank 3 is set as a structure that cannot be sucked below this.

The water is pumped from the anaerobic tank 3 to the quantitative transfer device 17 by the air lift pumps 10 and 15. Quantitative transfer device 17
Are high, the two-stage air lift pumps 10, 15
It has become. The to-be-processed water separated and settled in the anaerobic tanks 2 and 3 is pumped by the air lift pumps 10 and 15 to the quantitative transfer device 17 provided at a high position.

The first-stage air lift pump 10 has a suction port 10a located at a higher water level than the surface of the anaerobic tank 3 and is formed in a U-shape. Subsequently, a second-stage air lift pump 15 is combined. The suction side of the air lift pump 10 falls, and the air is pumped from a blower (not shown) to the rising side near the bottom of the U-shape by a U-shaped air lift pipe whose rising side rises high.

The air lift pumps 10 and 15 also have a flow rate adjusting function. Although the anaerobic tanks 2 and 3 have a storage function for adjusting the flow rate, the capacity V for adjusting the flow rate is obtained by the following formula using the flow rate fluctuation and the duration. V ≧ (6 / 16-1 / 24) × 1 × 0.2 × n (n: the number of persons to be treated) Further, the residence time T is set to 8 hours of the daily average sewage amount by the following formula. T ≧ V × 24 / 0.2 / n The capacity of the anaerobic tanks 2 and 3 is stipulated in the structural standards of the septic tank, and when the capacity of the anaerobic tanks 2 and 3 is determined, the water level satisfying the capacity at this time is determined. The maximum water level when adjusting the flow rate. The suction port 10a of the air lift pump 10 has a low water level at a position obtained by subtracting the flow rate adjustment tank capacity. That is, it is located at the suction port 10a of the air lift pump. Generally, high water level 42
Is set at a position 100 mm lower than the inflow pipe pipe low of the anaerobic tank 2, and 8 hours of the daily average sewage amount is calculated and positioned below this position, and the low water level 43, that is, the air lift pump 1 is set.
A suction port 10a height of 0 is determined. The anaerobic tanks 2 and 3 can be used as flow rate adjusting tanks by setting the height of the lower end of the advancing port of the partition walls of the anaerobic tanks 2 and 3 to a low water level 43 or lower.

Since the suction port 10a of the first-stage air lift pump 10 is located at the upper end of the U-shaped falling pipe, the low water level 43 of the anaerobic tank 3 as a flow rate adjusting tank is set. On the other hand, the high water level 42 is set to the height of the advection port 5 from the anaerobic tank 2. Therefore, if the capacity of the anaerobic tank 3 is set to 8 hours of the daily average amount of sewage according to the calculated value, the air lift pump 10
The suction port 10a is a position that satisfies this capacity and is a position lowered from the high water level 42.

Since there is no use during the night, there is no inflow water,
However, since the water is being pumped by the air lift pumps 10 and 15, the water level of the anaerobic tank 3 as the flow control tank drops to the low water level 43. The water to be treated continues to be transported by the air lift pumps 10 and 15 while being intensively ingested and stored the next morning, so that the quantitative transfer device 17 as a whole substantially uniformly transfers the water to the membrane filtration tank 25 in the next step. A sudden change in the water to be treated results in a change in the load on the membrane filtration device 25a, which significantly affects the treatment performance. Since the actual maximum water level is a flow control tank with a sufficient margin, the water level does not generally rise to the design maximum water level even if there is variation due to the inflow conditions.

The fixed-quantity transfer device 1 provided at a position sufficiently higher than the anaerobic tank 3 water level by the air lift pumps 10 and 15
7, and the water is transferred to the membrane filtration tank 25 of the next step. However, the membrane filtration tank 25 has a neck-length structure with an extended upper end to secure the high water level 42 of the membrane filtration device 25a. A tank with a watertight structure is formed. For this purpose, as shown in FIG. 1, the raised portions of the anaerobic layer 3 and the membrane filtration tank 25 are made to protrude from the ground surface GL.

As shown in FIG. 3, the inner wall of the membrane filtration tank 25 is completely joined to the ceiling of the tank main body 1a, and a manhole collar 45 is added along the outer periphery 46 of the manhole opening thereover to completely watertight. The state has been made. An overflow pipe 29 connecting the membrane filtration tank 25 and the anaerobic tank 3 is provided below the water supply pipe 18 above the membrane filtration device 25a.

In this embodiment, a manhole collar 45 or the like, which is usually used for deep filling up to 30 cm, is connected to the manhole outer peripheral portion 46, a table is provided, and the fixed amount transfer device 17 is moved from the position of the high water level 42 to about 30 cm. It is installed above the anaerobic tank 3 which is 600 mm higher. In addition, the manhole shape was rectangular in consideration of taking the filter membrane 26 in and out. In this way, the outer peripheral wall rises at the upper portion of the membrane filtration tank 25 as described above, so that a high water level can be secured.

The water to be treated is put into the membrane filtration tank 25 from the fixed quantity transfer device 17. In the membrane filtration tank 25, the membrane filtration device 2
5a is interpolated. A plurality of filtration membranes 26 are provided side by side in the membrane filtration device 25a, and adjacent filtration membranes 26 are provided.
Are connected to each other by a connecting pipe 33, the connecting water level of the connecting pipe 33 is set at a position sufficiently lower than the water level of the overflow pipe 29, and the discharge port 34 of the membrane filtration device 25a is provided at a position lower than the connecting water level.

The water to be treated is filtered at a head pressure caused by a head drop between the overflow pipe 29 and the discharge port 34 of the membrane filtration device 25a and stored in a treatment water tank 35.
The filter is filtered by the height of the advancing port 39a of the disinfecting tank 38 provided at a position higher than the discharge port 34 and sufficiently lower than the overflow pipe 29 and the head of the overflow pipe 29. The water level in the membrane filtration tank 25 is
The inflow water above a certain water level is returned to the anaerobic tank 3. Therefore, the water level of the membrane filtration tank 25 is determined by this.

As the membrane filtration device 25a, a set of six filtration membranes 26 is used as the membrane filtration device 25a, and a guide groove is provided on the base, and the filtration membrane 26 is housed therein.
A detachable connection tool is provided at the upper end of 6, and is connected to the connection pipe 33. Then, a discharge port 34 is provided from the final connection port of the sixth sheet through a partition wall between the treatment water tank and the discharge port 34 is connected to the treatment water tank 35.

The filtration membrane 26 has a width 61 in a rectangular casing.
Six filtration membranes of 0, height 1060 and thickness 13 mm were juxtaposed, and the pore diameter of the membrane was about 0.5 to 1 micron. The filtration membrane 26 is
A porous spacer made of foamed polypropylene or the like is interposed between a pair of permeable membrane films, and the periphery of the film is heat-sealed, and a plate is attached to the periphery of the periphery. The upper end of the filtration membrane 26 is 200 to
It was set 300 mm lower.

The filtrate which has passed through the filtration membrane 26 installed in the membrane filtration tank 25 which is an activated sludge treatment tank is connected to the connecting pipe 33.
And the water level in the membrane rises, and the discharge port 34 attached to the partition wall from the connection port of the filtration membrane 26 on the treated water tank 35 side.
Through the treatment water tank 35. The head between the discharge port 34 and the water level of the membrane filtration tank 25 becomes the head pressure of the membrane filtration 26,
As the water level in the treated water tank 35 rises, the head between the water level and the water level in the membrane filtration tank 25 becomes the head pressure. Eventually, the head between the position of the advancing port 39a of the disinfection tank 38 provided on the wall of the disinfection tank 38 and the water level in the membrane filtration tank 25 becomes the membrane filtration head pressure.

If the filtration speed of the filtration membrane 26 cannot keep up,
The water level in the membrane filtration tank 25 rises. Therefore, quantitative transfer device 1
7, an overflow pipe 29 is provided at a position lower than the water supply level to always secure inflow water at a filtration speed or higher.
, A high water level in the membrane filtration tank 25 can be secured. On the other hand, the upper end of the filtration membrane 26 is set at a position sufficiently lower than the water level of the membrane filtration tank 25, and each filtration membrane 26 is connected at the middle or lower level. If the position of the discharge port 34 of the connecting pipe 33 of the final filtration membrane 26 is also at the same height as the connecting pipe 33, a head difference corresponding to this height and a water level difference of the membrane filtration tank 25 is generated, and membrane filtration is performed.

The water to be treated which has been anaerobically decomposed in the anaerobic tanks 2 and 3 and flowed into the membrane filtration tank 25 by the air lift pumps 10 and 15 and the quantitative transfer device 17 is subjected to a secondary treatment (aerobic treatment) here. The membrane is filtered. The secondary treatment was activated sludge treatment. MLLS concentration of activated sludge concentration is more than 5000mg,
A diffuser tube and a backwash tube 30 (a synthetic resin tube having a diameter of 13 mm, which is formed in a comb shape at the lower end of the membrane filtration tank 25).
Laying at 0 mm intervals and opening air holes of 1 to 2 mm), and the strength is ³ air / m ^{3 of} water.
It has become a ~5m ^3.

After the water level in the treated water tank 35 rises, the water to be treated that has flowed into the disinfecting tank 38 from the disinfecting tank transfer port 39a opened in the upper wall of the disinfecting tank 38 shown in FIG.
It is naturally released from. The position of the bottom of the discharge pipe and the disinfection tank 38 is determined by setting the height of the discharge destination.
Is determined. Finally, the height of the advancing port 39a of the disinfection tank 38 and the head pressure of the membrane filtration tank 25 determine the membrane filtration speed. Water level of membrane filtration tank 25 and filtration membrane 26
, The actual head difference from the position of the advancing port 39a of the disinfection tank 38 determines the speed of membrane filtration.

As shown in FIG. 5, the disinfection tank 38 is provided with a pre-disinfection water chamber 39 so that the water to be treated stably contacts the chemical. When the water is stored and full, it overflows from an overflow port 40 provided on the ceiling of the pre-disinfection water chamber 39, flows down the overflow gutter section 41, is disinfected by the disinfectant in the medicine cylinder 42, and is discharged into the disinfection tank 38. Is done.

Therefore, the positions of the connection port and the discharge port 34 attached to the filtration membrane 26 do not have to be attached to the lower part. This is for discharging the pump up by a pump or the like in the future, and may be a position slightly lower than the height of the transfer port 39a of the disinfection tank 38 in consideration of maintenance. Connecting pipe 33
The length is set to ensure a necessary length when the filter membranes 26 are taken out one by one, and it is preferable that the connecting pipe is also rotatable and has a detachable structure. In the case of membrane filtration, not only removal of suspended substances and BDD but also denitrification are often required. For denitrification, it is necessary to constantly transfer the wastewater from the treated water tank 35 to the anaerobic tanks 2 and 3.

As described above, in the sewage treatment apparatus 1 of the present invention, the water to be treated is filtered by the head pressure due to the head drop between the overflow pipe 29 and the discharge port 34 of the membrane filtration device 25a and stored in the treatment water tank 35. Usually, the filtration is performed at a height higher than the discharge port 34 of the membrane filtration device 25a and sufficiently lower than the overflow pipe 29 and at a height of the advancing port 39a of the disinfection tank 38 and a head difference of the overflow pipe 29 water level. The upper manhole portion of the tank 25 is raised to raise the membrane filtration tank 2
By raising the water level of No. 5, the head difference between the height of the advancing port 39a of the disinfection tank 38 and the water level of the overflow pipe 29 can be increased, and the filtration speed can be improved without digging deeply into the tank.

In the sewage treatment apparatus 1 according to the second aspect of the present invention, the water to be treated transferred to the treated water tank 35 is supplied to the disinfection tank 3 shown in FIG.
8, the upper and lower water levels of the treated water tank 35 are controlled by float switches 37, 37, and are filtered by the head difference between the water level and the overflow pipe 29 water level of the membrane filtration tank 25. Float switches 37, 37 incorporating a function to control the water surface are attached to the treated water tank 35 by driving the pump to pump the water to be treated when the water level reaches a certain level, and stopping the driving when the water level falls to a certain level. Automatic operation submersible pump 36 is installed. Therefore, the head pressure of the filtration membrane 26 is determined by the positions of the float switches 37, 37.
Is determined by the head pressure between the water level of the membrane filtration tank 25 and the water level of the membrane filtration tank 25 (the low level of the overflow pipe 29).

As described above, when the water level reaches a certain level, the submersible pump 36 operates to pump up the treated water, and when the water level drops to a certain level, the operation is stopped and the water level in the treated water tank 35 can be automatically controlled. . Therefore, the water level of the discharge port 34 of the membrane filtration device 25a of the filtered treated water is adjusted by the submersible pump 36.
To keep it below a certain level by pumping it up to the disinfection tank 38,
The head pressure of the filtration membrane 26 can be maximized, and the filtration speed can be improved. In this way, by securing the water level of the treated water tank 35 at a lower position below a certain level by the submersible pump 36, the head pressure of the filtration membrane 26 of the membrane filtration device 25a can be significantly increased, and the filtration speed can be increased or In addition, the installation area of the expensive filtration membrane 26 can be reduced.

As shown in FIG. 3, the quantitative transfer device 17 of the sewage treatment apparatus 1 according to the present invention comprises a plurality of compartments, and the first compartment 17a has an inflow water discharge tip. 22 has a submerged structure, the second compartment 17b has a gate 23 capable of adjusting an opening area for returning surplus water to be treated to the anaerobic tank 3, and supplies water to the membrane filtration tank 25. Before the discharge, a V-shaped measuring device is provided. The water is transferred from the quantitative transfer device 17 to the membrane filtration tank 25 by the water supply pipe 18.

As shown in FIG. 3, the fixed amount transfer device 17
A first compartment 17a for receiving the water to be treated transferred from the stage air lift 15, a second compartment 17b incorporating an adjusting device for adjusting the transfer amount to the next step, and a V notch 2
4 and a third compartment 17c for simply measuring the amount of water supply and quantitatively transferring it to the membrane filtration tank 25. First compartment 1
An advection port is provided in the partition wall between 7a and the second compartment 17b and enters the second compartment 17b.

The to-be-processed water pumped by the fixed amount transfer device 17 flows into the first compartment 17a. Inflow water discharge tip 2
Numeral 2 is submerged so as to suppress the splash of the inflowing treated water and the violent movement of the water surface. Also, the first compartment 17a
The air discharged from the upper end of the tank is discharged to the treated water tank 35 through the exhaust pipe provided at the highest position. Second compartment 17b
Gate 2 for returning excess water to the anaerobic tank 3
A gate 23 adjusts the amount of the water to be measured to be measured and set by the V notch 24 in the third compartment 17c.

The water to be treated measured and set in the third compartment 17c is transferred to the membrane filtration tank 25 by a water supply pipe. Membrane filtration tank 25
Is returned to the anaerobic tank 3 by an overflow pipe 29 provided at a position about 50 mm lower than the bottom of the water supply pipe. The discharge port that flows from the first-stage air lift pump 10 into the fixed-quantity transfer device 17 is submerged in the water in the first compartment 17a, thereby suppressing the pulsating flow of the water to be treated and fluctuations in the water surface.

In general, the pumping amount is set excessively,
A gate 23 is provided in the second compartment 17b, the opening area is adjusted, and surplus water is returned to the anaerobic tank 2. Adjustment of the gate 23 is performed by the measuring device V in the third compartment 17c.
Adjustment of the return of excess water is performed so that a fixed amount can be sent to the membrane filtration tank 25 according to the scale of the notch 24. The discharge port 18 a of the water pipe 18 is provided at a high position above the membrane filtration tank 25.
In this way, the fixed amount transfer device 17 is
a, the second compartment 17b and the third compartment 17c are used not only for securing a head difference but also for the membrane filtration tank 25 in the next step.
In consideration of the stabilization of the load on the water, the water to be treated can be adjusted.

In the sewage treatment apparatus according to the fourth aspect of the present invention, an air diffuser / backwash pipe 30 is provided below a plurality of filtration membranes juxtaposed in the membrane filtration tank, and is optionally provided with air bubbles. The surface of the filtration membrane can be washed. In the membrane treatment device 25a, a secondary treatment, for example, an activated sludge treatment is performed, and soluble BOD in the water to be treated is decomposed. Therefore, an air diffuser 30 is provided below the filtration membrane 26 and is constantly aerated. In addition, a backwash pipe is provided separately from the air diffuser, or the outside of the filtration membrane 26 is washed as a mechanism that can also be used as the air diffuser to increase the amount of air.

As described above, an air diffuser / backwash tube 30 is provided below the plurality of filtration membranes 26 arranged in parallel in the membrane filtration tank 25a, and the surface of the filtration membrane 26 can be optionally washed with air bubbles. Therefore, the surface of the filtration membrane 26 can be washed at all times, and solid matter adhering to the surface of the filtration membrane 26 can be removed to prevent a decrease in filtration efficiency.

[0046]

In the sewage treatment apparatus according to the first aspect of the present invention, the water to be treated is filtered at the head pressure due to the head drop between the overflow pipe and the discharge port of the membrane filtration device and stored in the final treatment tank. Is filtered at the height of the aeration port of the disinfection tank provided at a position higher than the discharge port of the membrane filtration device and sufficiently lower than the overflow pipe and the head difference of the overflow pipe water level, so that the water level of the membrane filtration tank is raised, The water level at the outlet of the membrane filtration device of the treated water that has been filtered is pumped to the disinfection tank to keep the water level below a certain level to maximize the head pressure of the filtration membrane. The filtration area can be reduced, and the installation area can be reduced.

In the sewage treatment apparatus according to the second aspect of the present invention, the water to be treated transferred from the discharge port to the final treatment tank is pumped to a disinfection tank by a pump provided in the final treatment tank, and is subjected to final treatment. The upper and lower water levels of the tank are controlled by a float switch, and the water is filtered according to the head difference between the water level and the overflow pipe water level of the membrane filtration tank. When it is lowered, the operation is stopped and the water level in the final treatment tank can be automatically controlled.

According to a third aspect of the present invention, in the sewage treatment apparatus according to the present invention, the quantitative transfer device includes a plurality of compartments, and the first compartment has a structure in which a leading end of the inflow water discharge is submerged. The second compartment has a gate capable of adjusting an opening area for returning the excessively-treated water to be returned to the anaerobic tank, and a V-shaped measuring section is provided at the outlet before being supplied to the membrane filtration tank. Since the apparatus is provided, the water supply amount can be simply measured by a V-shaped measuring apparatus, and the treated water can be quantitatively transferred to the membrane filtration tank.

In the sewage treatment apparatus according to the fourth aspect of the present invention, a diffuser pipe and a backwash pipe are provided below the plurality of filtration membranes arranged in parallel in the membrane filtration tank, and the filtration is optionally performed by air bubbles. Since the surface of the membrane can be washed, the surface of the filtration membrane can always be washed, and a decrease in filtration efficiency can be prevented.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view of a sewage treatment tank incorporating a membrane filtration device of the present invention.

FIG. 2 is a horizontal sectional view of FIG.

FIG. 3 is an explanatory diagram showing a two-stage air lift pump and a fixed amount transfer device.

FIG. 4 is a cross-sectional view showing an enlarged main part of the sewage treatment apparatus.

FIG. 5 is a perspective view of a disinfection tank. DESCRIPTION OF SYMBOLS 1 Sewage treatment apparatus 1a Tank main body 2 Anaerobic tank 3 Anaerobic tank 5 Outflow port 10 Air lift pump 10a Suction port 15 Air lift pump 17 Quantitative transfer device 18 Water supply pipe 17a 1st compartment 17b 2nd compartment 17c 3rd compartment 23 Gate 24 V Notch 25 Membrane Filtration Tank 25a Membrane Filtration Device 26 Filtration Membrane 29 Overflow Pipe 30 Aeration Tube / Backwash Pipe 33 Connection Pipe 34 Discharge Port 35 Treatment Water Tank 36 Underwater Pump 37 Float Switch 38 Disinfection Tank 39a Transfer Port 42 High Water Level 43 Low water level

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) C02F 3/28 C02F 3/28 A

Claims (4)

[Claims] 1. An anaerobic tank, a membrane filtration tank in which a membrane filtration device having a plurality of filtration membranes inserted therein, and a treatment water tank provided with a disinfection tank at the top are provided by dividing the tank body. The anaerobic tank is provided with a quantitative transfer device at a position higher than the water level of the anaerobic tank, water is pumped from the anaerobic tank to the quantitative transfer device by an air lift pump, and the quantitative transfer device is a membrane filtration tank. Water is supplied by a water supply pipe, and an overflow pipe connecting the membrane filtration tank and the anaerobic tank is provided above the membrane filtration apparatus at a lower position of the water supply pipe, and a discharge port of the membrane filtration apparatus is provided below the membrane filtration apparatus. The water to be treated is filtered at the head pressure due to the head of the overflow pipe and the discharge port of the membrane filtration device and stored in the treatment water tank, and is usually located at a position higher than the discharge port of the membrane filtration device and sufficiently lower than the overflow tube. Advection height of the disinfection tank provided A sewage treatment apparatus characterized in that the sewage is filtered by a difference in head of the overflow pipe water level. 2. The treatment water tank is provided with a pump,
The water to be treated in the treated water tank is pumped to the disinfection tank by a pump, and the upper and lower water levels in the treated water tank are controlled by a float switch, and are filtered by the head difference between the water level in the treated water tank and the overflow pipe. The sewage treatment apparatus according to claim 1. 3. The fixed-quantity transfer device comprises a plurality of compartments,
The first compartment has a structure in which the inflow water discharge tip is submerged, and the second compartment has a gate capable of adjusting an opening area for returning excess water to be treated to the anaerobic tank. The sewage treatment apparatus according to claim 1, wherein a V-shaped measuring device is provided at an outflow portion before water is sent to the membrane filtration tank. 4. An air diffusion tube and a backwash tube are provided below a plurality of filtration membranes juxtaposed in the membrane filtration tank, and the surface of the filtration membrane can be optionally washed by air bubbles. A sewage treatment apparatus as described in the above.