JP2023069090A - purifier - Google Patents

Abstract

To provide a purifier with a simple structure, yet with excellent processing efficiency and energy saving.SOLUTION: A purifier 1 has a cylindrical septic tank 2, a raw water supply pipe 4 connected to a pump 3 that supplies raw water to the septic tank 2 by pumping with the pump 3, and a discharge pipe 7 that discharges treated water purified by an action of aerobic microorganisms in the septic tank 2. An air inlet 4b is provided in the middle of the raw water supply pipe 4, and a static mixer 6 is installed between the air inlet 4b and the supply port of the raw water supply pipe 4. Raw water and air are mixed and supplied to the septic tank 2 with the static mixer 6.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to a purification system, and more particularly to a purification system using an activated sludge method using aerobic microorganisms.

Wastewater containing contaminants such as high-concentration nitrogen components, phosphorus components, and organic substances that increase biochemical oxygen demand (hereinafter referred to as BOD) and suspended solids concentration (hereinafter referred to as SS) contributes to river pollution and red tides. It is a cause of environmental pollution such as generation. Conventionally, an activated sludge method (biochemical treatment), in which sludge is treated with microorganisms, has been widely used as a method for treating wastewater containing such highly concentrated contaminants.

Generally, the activated sludge method is a method of decomposing and removing pollutants by aerating the inside of a septic tank to promote the activity of aerobic microorganisms. In the activated sludge method, it is important to bring air into contact with aerobic microorganisms as much as possible. For example, in the biological treatment apparatus of Patent Document 1, in order to more efficiently treat organic substances contained in raw water, air bubbles contained in dissolved oxygen water are made finer by a pump and sent to a septic tank, thereby efficiently It is said that it is frequently oxidized by contact.

JP-A-10-151475

In the biological treatment apparatus of Patent Document 1, a carrier is suspended in a septic tank, and activated sludge adheres to and proliferates on this carrier to separate supernatant water and flocs. However, this device requires a carrier to float in the septic tank, a support bed, a mesh plate for preventing the carrier from flowing out, and the like, and the structure of the device tends to be complicated. In addition, an agitation pump is used to make the air bubbles fine and to dissolve them in the water to be treated, but there is room for improvement in terms of energy saving as well.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and an object of the present invention is to provide a purifying apparatus which has a simple structure and is excellent in treatment efficiency and energy saving.

The septic tank of the present invention comprises a cylindrical septic tank, a raw water supply pipe connected to a pump for supplying raw water to the septic tank under pressure by the pump, and treated water purified by the action of aerobic microorganisms in the septic tank. An air inlet for introducing air is provided in the middle of the raw water supply pipe, and between the air inlet and the supply port of the raw water supply pipe. A static mixer is provided, and the raw water and the air are mixed by the static mixer and supplied to the septic tank.

The septic tank has a cylindrical partition wall that divides the space inside the tank, the inside and the outside of the cylindrical partition wall communicate with each other through an opening at the lower end of the cylindrical partition wall, and the raw water supply pipe extends at the height of the septic tank. It is characterized by being inserted into the inside of the cylindrical partition in a direction orthogonal to the direction and arranged along the inner wall surface of the cylindrical partition.

The purification apparatus has a circulation pipe for circulating the water to be treated in the septic tank outside the tank, and the circulation pipe is connected to the raw water supply pipe so that the water to be treated introduced into the circulation pipe is the static The water to be treated in the septic tank is circulated inside the cylindrical partition and above the raw water supply pipe. A funnel is provided for introduction into the tube, the funnel being placed with the opening facing upwards.

The inner diameter of the cylindrical partition is 50% to 80% of the inner diameter of the septic tank.

It is characterized in that the cylindrical partition has a truncated cone shape.

The purification apparatus of the present invention includes a septic tank, a raw water supply pipe, and a discharge pipe. A static mixer is provided between the mouth and the raw water and air are mixed by the static mixer and supplied to the septic tank, so relatively fine air bubbles are generated without using a separate power source. In addition, by obtaining highly-concentrated oxygen water, the activity of aerobic microorganisms can be promoted in the septic tank. As a result, the purifying apparatus has a simple structure and is excellent in treatment efficiency and energy saving.

A septic tank has a cylindrical partition wall that divides the space inside the tank. Since it is inserted into the inside of the cylindrical partition in the direction of A swirling flow occurs at As a result, the water to be treated in the tank can be stirred, the activity of aerobic microorganisms is promoted, and the treatment efficiency is further improved. In addition, since it is not necessary to provide an agitating device for agitating the inside of the septic tank, it is also excellent in energy saving.

The purification apparatus has a circulation pipe for circulating the water to be treated in the septic tank outside the tank, and the circulation pipe is connected to the raw water supply pipe. Since there is a circulation path for re-supply, the treatment capacity can be improved without increasing the size of the septic tank. Furthermore, inside the cylindrical partition and above the raw water supply pipe, a funnel is provided for introducing the water to be treated in the septic tank into the circulation pipe. Since it is installed at the same position, the water to be treated that rises due to the swirling flow is easily introduced into the circulation pipe. As a result, the circulation efficiency of the water to be treated can be improved, and the treatment efficiency can be improved.

Since the cylindrical partition has a truncated cone shape, the settling speed of the activated sludge outside the cylindrical partition can be increased, and the treatment efficiency can be improved.

1 is a schematic diagram of one embodiment of a purification device of the present invention; FIG. It is a height direction sectional view of the septic tank of FIG. It is the top view which looked at the inside of the tank of a septic tank from the top. It is a figure which shows circulation of to-be-processed water and activated sludge in a septic tank. It is a height direction sectional view of the septic tank of other embodiment of the purification apparatus of this invention.

One embodiment of the purifier of the present invention will be described with reference to FIG. FIG. 1 is a schematic diagram of a purifier. The wastewater treatment method using the purification apparatus of the present invention is a method of decomposing and removing contaminants in wastewater by aerating the inside of the septic tank to promote the activity of aerobic microorganisms. The raw water supplied to the purifier 1 may be sewage, industrial waste water, sludge water such as industrial waste water, or primary treated water in which suspended solids have been precipitated and removed by anaerobic microorganisms.

As shown in FIG. 1, the purification device 1 includes a cylindrical septic tank 2, a pump 3, a raw water supply pipe 4 for supplying raw water to the septic tank 2, and treated water purified by the action of aerobic microorganisms in the septic tank 2. , a circulation pipe 10 for circulating the water to be treated in the septic tank 2 outside the tank, and a discharge pipe 11 for discharging activated sludge. In the present invention, the internal volume of the septic tank 2 is not limited, and can be adapted from a small size to a large size. The internal volume is, for example, 1 m ³ to 30 m ³ , preferably 1 m ³ to 15 m ³ .

The raw water supply pipe 4 is connected to the pump 3, and the raw water is supplied to the septic tank 2 from the supply port 4a by the pump 3. As shown in FIG. 1, an air inlet 4b connected to an air pipe 5 is provided in the middle of the raw water supply pipe 4. As shown in FIG. By introducing air from the air inlet 4b, raw water and air are mixed on the downstream side of the air inlet 4b. A structure in which air is supplied by a blower (not shown) may be used, and the raw water supply pipe 4 may have a structure in which air is sucked into the pipe.

The present invention is characterized in that a static mixer 6 is provided in the raw water supply pipe 4 between the air inlet 4b and the supply port 4a. The raw water and air are stirred and mixed by the static mixer 6 to generate relatively fine air bubbles and to dissolve oxygen in the water to obtain high-concentration oxygen water. By supplying the high-concentration oxygen water with fine bubbles to the septic tank 2, the activity of aerobic microorganisms is promoted and the treatment efficiency is improved. The size of the microbubbles is, for example, 10 μm to 100 μm, preferably 10 μm to 50 μm. In addition, when the bubble size is nano-sized (less than 1 μm), the bubble itself is stabilized and thus becomes difficult to dissolve.

In the purifying apparatus of the present invention, the energy consumption can be suppressed by providing the static mixer 6 which is a static stirring means without providing the conventional dynamic stirring means when supplying the water to be treated. In addition, by configuring the static mixer 6 to be detachable from the raw water supply pipe 4, cleaning and maintenance are easier than with dynamic stirring means.

A static mixer is a structure having one or more elements in the form of, for example, a rectangular plate twisted 180 degrees. In the static mixer, the air bubbles in the raw water are made finer and the contact interface is enlarged, so that the dissolution efficiency of the air is enhanced and the oxygen-rich water is obtained. A known static mixer can be used as the static mixer.

Generally, the saturated dissolved oxygen content is 8.84 mg/L at 20° C. and 1 atmospheric pressure. In order to keep the amount of dissolved oxygen in the oxygen-rich water discharged from the supply port 4a after passing through the static mixer in a suitable range, it is preferable to mix raw water and air in an appropriate ratio. The flow rate of the raw water can be measured by flowmeters F1 and F2, and the amount of blown air can be measured by a flowmeter (not shown) provided on the air pipe 5 or the like.

In FIG. 1, the septic tank 2 has a true cylindrical appearance consisting of a base 2a serving as a bottom surface, a cylindrical side surface 2b and an upper surface portion 2c. A raw water supply pipe 4, a discharge pipe 7, a circulation pipe 10, and a discharge pipe 11 are connected to the cylindrical side surface 2b. The connection positions of the cylindrical side surface 2b and each pipe are arranged in the order of the discharge pipe 7, the circulation pipe 10, the raw water supply pipe 4, and the discharge pipe 11 in the height direction of the septic tank 2 from the top. The circulation pipe 10 and the discharge pipe 11 are connected outside the septic tank and further connected to the pump 3 . By operating the pump 3, the water to be treated in the septic tank can be circulated and the activated sludge can be discharged.

Next, the internal structure of the septic tank will be described with reference to FIGS. 2 and 3. FIG. FIG. 2 is a cross-sectional view of the septic tank in the height direction, and FIG. 3 is a plan view of the inside of the septic tank viewed from above. As shown in FIG. 2, the septic tank 2 has a cylindrical partition wall 8 that divides the space inside the tank. The cylindrical partition 8 is suspended from the upper surface 2c of the septic tank 2 and fixed. The upper end of the cylindrical partition 8 is closed and the lower end is opened by an opening 8a. The space inside the tank of the septic tank 2 is divided into an inside (cylindrical inner tank 2d) and an outside (cylindrical outer tank 2e) by a cylindrical partition wall 8, and the cylindrical inner tank 2d and the cylindrical outer tank 2e communicate with each other through an opening 8a. .

A raw water supply pipe 4 is horizontally arranged in the lower part of the cylindrical inner tank 2d. The raw water supply pipe 4 has its supply port 4a arranged sideways. The height position (central position in the height direction) of the supply port 4a is set at a height of 0.1H to 0.3H from the base 2a, where H is the height from the base 2a to the upper surface 2c of the septic tank 2. preferably.

A funnel 9 and a circulation pipe 10 are arranged above the raw water supply pipe 4a and above the cylindrical inner tank 2d. The funnel 9 has a circular opening 9a, and has a shape that expands toward the opening 9a. In the cylindrical inner tank 2d, the funnel 9 is installed with the opening 9a facing upward. The height position of the opening 9a is preferably set at a position higher than the tank height H by 0.8H from the base 2a.

The inner diameter _φa of the septic tank 2 is not particularly limited, but is, for example, 100 to 300 cm. The inner diameter φ _b of the cylindrical partition 8 is preferably 50% to 80% of the inner diameter φ _a of the septic tank 2 . The opening dimension φ _c of the opening 9 a of the funnel 9 is preferably 50% to 80% of the inner diameter dimension _φ b of the cylindrical partition 8 . In particular, the inner diameter dimension φ _b of the cylindrical partition 8 is 60% to 80% of the inner diameter dimension φ _a of the septic tank 2, and the opening dimension φ _c of the opening 9a of the funnel 9 is equal to the inner diameter dimension φ of the cylindrical partition 8. It is more preferably 60% to 80% of _b .

A groove-shaped collection path 12 is provided over the entire circumference of the upper portion of the cylindrical outer tank 2e. The collection path 12 is connected to the discharge pipe 7 . The treated water introduced into the recovery path 12 over the side wall 12 a is discharged from the discharge pipe 7 .

A lower inner surface of the cylindrical outer tank 2e is an inclined surface 2f whose diameter decreases toward the bottom. The inclination angle of the inclined surface 2f in the cross section in the height direction of the septic tank 2 is, for example, 20 degrees to 60 degrees. In addition, the lower end of the cylindrical partition 8 is arranged close to the inclined surface 2f. A sludge sedimentation part is formed at the sloped surface portions arranged close to each other, and the sludge is thickened and the treated water is separated. Also, by arranging the lower ends of the cylindrical partitions 8 close to each other, rapid forced sedimentation of the sludge becomes possible. The distance between the lower end of the cylindrical partition 8 and the inclined surface 2f is preferably adjusted according to the type and amount of sludge.

The activated sludge deposited on the bottom of the cylindrical outer tank 2e is discharged out of the tank through the discharge pipe 11. As shown in FIG. The discharge pipe 11 is arranged with the discharge port 11a facing upward in order to facilitate discharge of the activated sludge.

FIG. 3 is a top plan view of the inside of the septic tank. As shown in FIG. 3, the funnel 9, the cylindrical partition 8, the collection path 12, and the septic tank 2 are arranged concentrically. The raw water supply pipe 4 and the circulation pipe 10 are inserted through the cylindrical side surface 2b of the septic tank 2 and the cylindrical partition wall 8 to the inside of the cylindrical partition wall 8. In FIG. It has become. The end of the raw water supply pipe 4 is arranged along the inner wall surface of the cylindrical partition 8 . With this arrangement, the oxygen-rich water discharged from the supply port 4a flows along the R of the inner wall surface, and a swirling flow is generated in the cylindrical inner tank 2d. The water to be treated in the cylindrical inner tank 2d mixes with the high-concentration oxygen water and has a relatively high dissolved oxygen content.

Here, in a general septic tank, an agitator is provided in the tank, and agitation by the agitator promotes the activity of aerobic microorganisms. On the other hand, in the septic tank of the present invention, a static mixer is used to generate highly-concentrated oxygen water, and the highly-concentrated oxygen water is released to generate a swirling flow, so that a dynamic stirring device is not required. The efficiency of the aerial microbial treatment reaction can be improved.

A waste water treatment method using the purification device 1 will be described below with reference to FIG. FIG. 4 is a diagram for explaining the flow paths of the water to be treated and the activated sludge in the septic tank 2. As shown in FIG. In FIG. 4, the shaded area indicates the area where the concentration of activated sludge is high, and the arrow indicates the circulation direction of the water to be treated and the activated sludge.

In FIG. 4, V1 to V8 are valves for adjusting flow paths and flow rates of raw water and circulating water, and F1 to F2 are flowmeters. The valves V1 to V4 are provided on the raw water supply pipe 4, the valves V5 to V7 are provided on the circulation pipe 10, and the valve V8 is provided on the discharge pipe 11. Note that the discharge pipe 11 is connected to the circulation pipe 10 on the way. In the purification device 1 of FIG. 4, the valves V1 to V8 are opened and closed based on the flow rate of the raw water measured by the flowmeters F1 to F2. Opening and closing of the valve may be performed automatically by a flow controller (not shown).

Raw water containing contaminants whose solid content has been separated by, for example, a wedge wire screen or the like is introduced into the purification device 1 of FIG. The BOD and SS of raw water to be introduced are preferably measured in advance. For example, as raw water, BOD is 800 mg/L or more, chemical oxygen demand (hereinafter referred to as COD) is 300 mg/L or more, and total nitrogen content (hereinafter referred to as TN) is 40 mg/L or more. be done. It is also suitable for treatment of raw water containing normal-hexane-extracted oil concentrations in the range of 50 mg/L or more.

A part of the raw water supply pipe 4 is connected to the pump 3, and the raw water is supplied into the septic tank 2 by operating the pump 3 with the valves V1 to V4 open. At this time, the raw water is agitated and mixed with air in the static mixer 6 to form highly oxygen-concentrated water and discharged from the supply port 4a. The amount of air introduced from the air pipe 5 is adjusted, for example, based on the flow rate of raw water.

As described above, the raw water supply pipe 4 is inserted into the septic tank 2 in a direction orthogonal to the height direction of the septic tank 2 and arranged along the inner wall surface of the cylindrical partition 8 (see FIG. 3). As a result, the oxygen-rich water discharged from the supply port 4a flows along the inner wall surface R of the cylindrical partition 8, generating a swirling flow as shown in FIG. The swirling flow rises slowly while having a relatively high dissolved oxygen state, and comes into contact with aerobic microorganisms in the water to be treated one after another, and the nitrification reaction, which is an aerobic microorganism treatment reaction, proceeds. A part of the activated sludge produced by this reaction settles at the bottom of the septic tank 2 . On the other hand, part of the water to be treated in the cylindrical inner tank 2d (the water to be treated once treated in the septic tank 2) and activated sludge is introduced from the funnel 9 into the circulation pipe 10 as circulating water.

The circulation pipe 10 is connected to the raw water supply pipe 4 via the pump 3, and the circulating water passes through the static mixer 6 and is supplied to the septic tank 2 again. The circulating water is circulated by operating the pump 3 with the valves V5 to V7 and V2 to V4 open. Since the circulating water contains aerobic microorganisms, returning the circulating water to the septic tank 2 can further promote the activity of the aerobic microorganisms. In addition, since the circulating water passes through the static mixer 6, it becomes high-concentration oxygen water and is supplied again.

When circulating the circulating water, the valve V1 of the raw water supply pipe 4 may be opened to mix the circulating water and the raw water. The flow rate of raw water to be mixed is adjusted based on the measured values of flowmeters F1 and F2.

The highly oxygen-concentrated water based on the circulating water discharged from the supply port 4a again generates a swirling flow, and the aerobic microbial reaction proceeds efficiently in the cylindrical inner tank 2d. Part of the water to be treated in the inner cylindrical tank 2d flows into the outer cylindrical tank 2e through the opening 8a of the cylindrical partition wall 8 and rises. In the cylindrical outer tank 2e, the supply of oxygen is cut off, the reaction of aerobic microorganisms stops, and the activated sludge slowly settles and deposits on the bottom. The treated water purified by sedimentation of activated sludge overflows into the recovery path 12 . In the septic tank 2, since the upper part of the tank is divided by the cylindrical partition wall 8, it is possible to prevent the purified treated water from mixing with the water to be treated again. Finally, the treated water is discharged from the discharge pipe 7 and reused as flush water for toilets in the facility. Moreover, you may discharge to a river, a sewer, etc. as needed.

Activated sludge deposited on the bottom of the septic tank 2 is discharged from the discharge pipe 11 by the pump 3 . This activated sludge may be discharged outside the purification apparatus 1 or may be supplied to the septic tank 2 again.

The septic tank 2 contains 5,000 to 12,000 mg/L of activated sludge in terms of solid content, and as the nitrification reaction progresses, the pH of the water to be treated decreases. The pH, oxidation-reduction potential (hereinafter referred to as ORP) and dissolved oxygen content (hereinafter referred to as DO) of the liquid to be treated are measured by a treated water quality measuring device (not shown). The amount of treated water to be circulated is determined. Specifically, the water to be treated is circulated by adjusting the air blowing amount and the like so that the ORP can be maintained at +10 mV or more in the aerobic reaction treatment section (cylindrical inner tank 2d) where the nitrification reaction takes place.

In the case of treatment by the wastewater treatment method according to the present invention, even if the raw water has a BOD of at least 800 mg/L and a T-N of 40 mg/L or more, the BOD of the treated water is usually extremely low, generally 20 mg/L or less. can be operated with a BOD of 10 mg/L or less as the water quality of the effluent.

The purification device of the present invention is not limited to the embodiments shown in FIGS. 1-4. FIG. 5 shows another embodiment of the purifier. FIG. 5 is a cross-sectional view of the septic tank 2' in the height direction. The septic tank 2' in FIG. 5 is the same as the septic tank 2 in FIG. In the septic tank 2 of FIG. 2, the cylindrical partition wall 8 has a right cylindrical shape with the same area on the upper and lower surfaces, whereas in the septic tank 2' of FIG. It has a truncated cone shape.

As shown in FIG. 5, when the cylindrical partition wall 8 has a truncated cone shape, the surface area of the liquid surface A of the water to be treated in the cylindrical outer tank 2e is larger than when it has a right cylindrical shape (see FIG. 2). The sedimentation speed of the activated sludge increases as the surface area of the liquid surface A increases. Therefore, by forming the cylindrical partition wall 8 into a truncated cone shape, the sedimentation speed of the activated sludge in the cylindrical outer tank 2e is increased, and as a result, the wastewater treatment speed can be increased. Further, when the cylindrical partition wall 8 has a truncated cone shape, the inner diameter of the cylindrical inner tank 2d decreases upward. This gradient makes it easier to maintain the swirling flow generated in the inner cylindrical tank 2d, and allows efficient stirring in the inner cylindrical tank 2d. Further, as shown in FIG. 5, even if the inner diameter of the cylindrical partition 8 changes, it is preferable that the inner diameter varies within a range of 50% to 80% of the inner diameter of the septic tank 2'.

Moreover, the wastewater treatment method according to the present invention can be performed in combination with a conventional wastewater treatment method. For example, by connecting an existing anaerobic denitrification tank and the purifier of the present invention and supplying primary treated water treated with anaerobic microorganisms as raw water to the purifier of the present invention, the sludge load can be more effectively reduced. Nitrification as well as denitrification and dephosphorization can be performed.

The purifying apparatus of the present invention has a simple structure and is excellent in treatment efficiency and energy saving. Therefore, it can be used as a purifying apparatus in facilities such as buildings and restaurants.

1 purification device 2, 2' septic tank 2a base 2b cylindrical side surface 2c upper surface portion 2d cylindrical inner tank 2e cylindrical outer tank 2f inclined surface 3 pump 4 raw water supply pipe 4a supply port 4b air inlet 5 air pipe 6 static mixer 7 discharge pipe 8 cylindrical partition 8a opening 9 funnel 9a opening 10 circulation pipe 11 discharge pipe 12 recovery path

Claims (5)

It comprises a cylindrical septic tank, a raw water supply pipe that is connected to a pump and supplies raw water to the septic tank by pumping the pump, and a discharge pipe that discharges treated water purified by the action of aerobic microorganisms in the septic tank. A purification device,
An air inlet for introducing air is provided in the middle of the raw water supply pipe, and a static mixer is provided between the air inlet and the supply port of the raw water supply pipe,
A purifier, wherein the raw water and the air are mixed by the static mixer and supplied to the septic tank. The septic tank has a cylindrical partition that divides the space in the tank, and the inside and the outside of the cylindrical partition communicate with each other through an opening at the lower end of the cylindrical partition,
2. The raw water supply pipe is inserted into the cylindrical partition wall in a direction orthogonal to the height direction of the septic tank and arranged along the inner wall surface of the cylindrical partition wall. Purification device as described. The purification device has a circulation pipe for circulating the water to be treated in the septic tank outside the tank, and the circulation pipe is connected to the raw water supply pipe so that the water to be treated introduced into the circulation pipe is the static It has a circulation path that passes through the mixer and is supplied again to the septic tank,
Inside the cylindrical partition and above the raw water supply pipe, a funnel is provided for introducing the water to be treated in the septic tank into the circulation pipe, and the funnel has an opening. 3. The purifier according to claim 2, wherein the purifier is installed facing upward. 4. The purification apparatus according to claim 2, wherein the inner diameter of said cylindrical partition is 50% to 80% of the inner diameter of said septic tank. A purification device according to any one of claims 2 to 4, characterized in that said cylindrical partition is frusto-conical.

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